POVIJEST ISTRAZIVANJA I EKSPLOATACIJE BITUMINOZNIH I KEROGENIH NALAZISTA HRVATSKE

Abstract

It is assumed that the first known sediments of natural bitumen or asphalt in coastal Croatia were exploited as the early moddle ages. Yet authenticated written documents about Vinisce near Trogir derive from no earlier than 1628, about Vrgorac/Paklina from only 1753. By the end of the 18th century, many deposits were discovered in Dalmatia, but it was Skrip on the Island of Brac and Suhi Dolac that were important. The earliest known deposits and occurrences of kerogenous rocks, or bituminous or oil shales, are mentioned as stone or fossil coal in Sovinjak, in the upper course of the River Mirna, and in Rebici in Istria; near Sinj, Slivno not far from the River Neretva, Mirca and near Nerezisce on the Island of Brac. All if these were well known and described in 1804, while Sovinjak was mentioned in the 16th century. In the article, some of new information derived from mining and geological research into bituminous and kerogenous sediments and deposits are provided. [PUBLICATION ABSTRACT]

Headnote

Kljucne rijeci: NalaziSta, Bitumen, Kerogen, Povijest Geologija, Rudarstvo

Najstarija IeZiSta prirodnog bitumena, odnosno asfalta, u primorskoj Hmatskoj, pretpostavlja se da su bila eksploatirana ve6 u srednjem vijeku. Sigurni pisani dokumenti o VlniSCu kod Trogira potjeh iz 1628., a o vrgoratkoj Paklini iz 1753. Do kraja XVIII. stolje6a otkriveno je u Dalmaciji vise nalaziSta,no znatajni su biii hip na otoku BraEu i Suhi Dolac.

Najstarija nalaziSta i l&Sta kerogenih stijena, odnosno "bituminoznih" ili "uljnih Skriljavaca" spominju se kao kameni ili fosilni ugljeni u Sovinjaku u gornjem toku rijeke Mime i u RebiCima u Istri, zatim kod Sinja, Slivna nedaleko Neretve, Mire ("Smirk") i kod NereZiSCa na BraEu. Sva su ona opisana 1804., a Sovinjak se spominje veC u XVI. stoljeCu.

NaSe najstarije nalaziSte oksidiranog zemnog ulja je Peklenica u Medimuju, a pretpostavlja se da je bila poznata vet u XVI. stoljeCu.

IzloZene su i nove spoznaje o rudarsko-geoloSkim istrazivanjima bituminoznih i kerogenih stijena i IefiSta.

Key-words: Deposits, Bitumen, Kerogen, History, Geology, Mining

It is assumed that the first known sediments of natural bitumen or asphalt in coastal Croatia were exploited as the early moddle ages. Yet authenticated written documents about Vinisce near Trogir derive from no earlier than 1628, about Vrgorac/Paklina from only 1753. By the end of the 18th century, many deposits were discovered in Dalmatia, but it was Skrip on the Island of Brac and Suhi Dolac that were important.

The earliest known deposits and occurrences of kerogenous rocks, or bituminous or oil shales, are mentioned as stone or fossil coal in Sovinjak, in the upper course of the River Mirna, and in Rebici in Istria; near Sinj, Slivno not far from the River Neretva, Mirca and near Nerezisce on the Island of Brac. All if these were well known and described in 1804, while Sovinjak was mentioned in the 16th century.

In the article, some of new information derived from mining and geological research into bituminous and kerogenous sediments and deposits are provided.

Uvod

Povijest istragivanja i eksploatacije bituminoznih nalaziSta, odnosno prirodnih asfalta te kerogenih nalaziSta, odnosno "bituminoznih" ili "uljnih Skriljavaca" nekada zamjenjivanim s "kamenim" ili "fosilnim ugljenom", povezuje se u nas, po starim dokumentima za rani novi vijek. Tada su zabiljeZeni prvi podaci o kopanju "pisasfalta" (piss asphaltus) "blizu Hvara nedaleko od Neretve" u Dalmaciji (M at t h i o 1 i, 1565), "zemnog voska" u Panoniji i "pegole" (pakline) u ViniSCu 1628. i 1668. (P r i u 1 i, 1668, B a rb a r o, 1670).

U Hrvatskoj pronalaze se u XVIII. i XIX. stoljeCu nova nalazsta pakline i otvaraju rudnici (Paklina, &rip i dr.). Sredinom XIX. stolieb zapotinje kod nas i prerada pakline (ViniSCe, Skrip i dr.). Pored toga, dio asfalta se izvozi i preraduje u Veneciji. Vrhunac proizvodnje asfalta dostignut je u drugoj polovini XIX. i poktkom XX. stoljeh.

Jeli asfalt kopan u nas i u srednjem vijeku moZe se nagadati , no s asfaltom (pegolom) se svakako trgovalo. 0 tome postoje dokumenti iz XV. stoljeh, poput zapisa u oporuci zadarskog svetenika Zubine iz 1437. (S u r m i n, 1898). Na poledini oporuke zapisano je da mu je 3. RaCiL duZan za "pakaln (bitumen) 39 bolant. U spisu iz 1381. zadarskog biljegnika Petrusa de Sercane, koji je sasluSao kapetana talijanske barke Simon pok. Baghinija de Bertanora, piSe da je isti pokugao prikriti u barci 12 bahi bitumena ("pegola").

IstraZivanja i eksploatacija kerogenih stijena (uljnih Skriljavaca") vezana su sa sigurnoSCu za novi vijek i to za konac XVIII. stoljeh kad je 1782. spomenuto bratko nalaziSte Smrille kod Mirce i neka manja nalaziSta na kopnu, te za konac XIX. stoljeb, kada su otkrivena naSa najveh nalaziSta Ruda kod Sinja kao i pljeSiviCki uljni Skriljavci: Vrelo KoreniEko, Baljevac, Zavalje i dr.

U proSlosti je primjena prirodnih bitumena i umjetnog katrana imala veliko znaknje za hidroizolaciju drvenih brodova i u ratnim potrebama, a "uljnih Skriljavaca" ponajprije u zdravstvu, veterini i dr. Svoju najznabjniju primjenu dosegnula je u XIX. i XX. stoljeCu kao alternativni izvor energije. Cilj je ovih istraBivanja upoznati povijest jedne grane rudarstva koja je u proSlosti bila dosta znabjna u ospodarstvu Hrvatske, a posebice Dalmacije i Like. b ljelo se dobiti vise uvida u naSu ranu rudarsku poduzetnitku djelatnost, a i prikazati iskustva iz obnovljenog rudarsko-geoloSkog istraiivanja bituminoznih i kerogenih nalaziSta Hrvatske.

Prirodni bitumen i kerogen u stijenama

Prema preporuci studijske grupe World Petroleum Congress (M a r t i n e z et al. 1987) "prirodni bitumen je dio nafte koji se nalazi u polukrutom stanju u prirodnim nalazistima. To je smecta do crna ljepljiva i rastezljiva tvar, a sastoji se preteino od ugljikovodika (66%-89%), te od vodika (7%-12%), sumpora (1%-lo%), duSika (<I%) i kisika (1%-2%). Heteroelemenata ima najMCe <lo%. test0 je oneCiSCena mineralnom tvari, a ako infiltrira ilili impregnira stijenu tada je to bituminozna stijena.

Poznati sinonim za bitumen (lat.) je asfalt (grE.). Taj je izraz kasnijom uporabom u Europi poprimio homonimsko znaknje, jer se upotrebljava za stijenu infiltriranu i/ili impregniranu prirodnim bitumenom. Stariji hrvatski izrazi za bitumen supakal (V r a n E i C, 1595) ilipek(e)4 koji S k o k (1972) povezuje s paklom. Paklina ili Paklenica su u nas ponegdje geogralkki nazivi nalaziSta prirodnog bitumena, odnosno asfalta. Izraz bitumen prevodio se i sa smolom (B e 1 1 o s z t en e c z, 1760).

"Bituminozni Skriljavci" su smjese organske i anorganske tvari iz kojih se dobiva ulje, pa odatle naziv i "uljni Skriljavci". Uljne Skriljavce karakterizira vrlo tanki stratiformni poloZaj naslaga. ViSe ili manje su obogaQni s organskom tvari, kasnije nazvanom kerogen, pa odatle i nazivi kerogene stijene (S c h 1 at t e r 1968, Y e n et al., 1976). Naziv ukazuje da se njegovim zagrijavanjem dobiva (parafinski) vosak ili ulje. Kerogen je fosilizirana organska tvar netopiva u uobihjenim organskim otapalima, dok je bitumen topiv (D u r a n d, 1980). Kerogene stijene mogu biti zanimljive za naftno-geoloSka istrafivanja, ako su zrele, jer su matiCne stijene za ugljikovodike.

Ima li u stijeni u organskoj tvari kerogena i bitumena (sl. 1) tada su to bituminozni kerogenci ili kerogeni hitumenci. ovisno &ga ima vise ($ e h e C i C. 1983). Prevladava li pak u ukupnoj organskoj tvari bitumen (>90%) tada su to "Cisti bitumen(c)iN.

Prvu slotenu podjelu bituminoznih karbonatnih stijena naCinio je autor (3 e b e C i C, 1978) prema strukturno-tebturnim svojstvima karbonatnih stijena, ukljuCujuCi njihov mineralni i kemijski sastav, zatim prema podjeli bitumena i pora u stijeni u kojoj se nalazi bitumen.

Potrebno je istaknuti da u jalovim stijenama s vrlo niskim sadriajem organske tvari mogu postojati odnosi bitumena i kerogena u ukupnoj organskoj tvari, kao i u "pravih" bituminoznih, bituminozno-kerogenih i kerogenih stijena, Sto nema praktiCno znaknje u primjeni, izuzev ako se studiraju odnosi u akumulaciji i migraciji navedenih sastojaka.

Osim podjela temeljenim na odnosu sadriaja bitumena i kerogena u ukupnoj organskoj tvari (sl. I), moguCe je u skladu s podjelom S c h m i t z a (1986) jednotipne organolite s asfaltom, koje on naziva "sirovi asfalt" nazvati "a s f a I t a c". Korigirani bi niz tada glasio: Eisti asfalt - asfaltac - asfaltna stijena, Sto bi sa sinonimom '!bitumen" u naSim razmatranjima bilo: bitumen- bitumenac-bituminozna stijena, te niz: kerogen-kerogenac-kerogena stijena. Temelj ovih podjela svodi se na sadrbj mineralne tvari <lo%, 10%-50% i >50%. U sloZenim podjelama s bitumenom i kerogenom naziv se odreduje prema prevladavajukm tipu organske tvari.

Bituminozna IeZiSta i nalazigta

Prema poznatim objavljenim podacima jedno od najstarijih nalazigta smolastog asfalta (pissasphaltus) nalazi se "blizu Hvara nedaleko od Neretve" (M a t th hi o 1 i, 1565), a Sto se mofe odnositi na vrgoratku Paklinu ili neretvljansko Slivno (sl. 2). F o r t i s (1774) pretpostavlja da je vrgoratki rudnik radio prije nego Sto je "rnletaEko o d j e omjilo ovaj kraj". To se i Eini logihim, jer samo je veliko nalaziSte moglo imati dugu povijest eksploatacije. 0 asfaltnom nalazstu Paklina postoje dokumenti iz arhiva (B o 1 d u, 1782) iz kojih je vidljivo da je hrvatsko rudarsko poduzetniStvo u vrgoratkom kraju bilo dobro organizirano ved 1753. (s1.3), a o tomu su pisali N o v a k (1%2), S o 1 d o (1978), P e r i E i C (1980) i dr. K i S p a t i C (1901) piSe, prema navodima F r i e s e a, da su "asfaltni kamen u I Vrhgorcu vet pred 150 god. (tj. 1708, op. ) - vadili, pa da su se radi njega mnoge pravde vodile".

U Dalmaciji je rudarska proizvodnja u 1850, iznosila pribli2no 1000 beEkih centi (bC.c) (56 t) asfalta i preko 40 000 bC.c (2240t) asfaltnih stijena, koje su prevozili u Veneciju na pripremanje asfaltnog mastiksa (F r i e s e, 1852).

Rudarsku aktivnost u Paklini sredinom XIX. stoljeb nastavlja barun R o t s c h i I d, a od njega rudnik preuzima tvrtka L.Konig i sin iz Beb. Rudarilo se na tri revira: Paulina, Marqa i Aleksand(er)rija, prema imenima Konigove djece. Godine 1906. preuzima rudnik Paulina Konig a potom iste godine, t.t. Asphalt Gewerhchaj? "Adria" iz Splita, te 1930. t.t. "Ruda" d.d. iz Sp1ita.- Od 1949.-1950. istraZivanje obnavlja Nafiaplin iz Zagreba, a 1953. osniva se rudarsko poduzefe "Paklina", koje se 1961. integriralo sa specijaliziranim gradevinskim poduzefem "Izolacija~' iz Beograda tiji je, oko 25 godina, bio pogon.

Do 1961. u Paklini se rudarilo podzemno. Poslije se eksploatacija provodila povkinskim kopom. Priblifna proizvodnja asfalta prikazana je u tablici 1.

Utvrdeno je da se poslije dufih prekida, izazvanih svjetskim ratovima, stari jamski radovi dijelom popune prirodnim bitumenom, pa se udjel kvalitetnije sirovine povremeno povetavao (sl. 4).

Cijedenje bitumena iz pukotina i Spiljskih prostora vidljivo je i danas na povrSinskom kopu (s1.5.)

Bitumen ispunjava prsline i druge sitnije Supljine, ali / 1 drobivu sitnef. Ima ga manje ili vise u bituminoznim vapnencima i bituminoznoj vapnenaCkoj tektonskoj breEi. U Paklini se rudarilo kombinacijama okana ilili niskopa te hodnika. Preteino se rudarilo do 50m dubine, gdje je lociran najdublji IV horizont. Niskopom (11) usmjerenim iz I1 horizonta na 25m do dubine 75m-80m, (prema "Izvadku iz starog rudarskog nacrta M 1:1000, koji je natinjen 12.6.1945.g. u Splitu", a nalazi se u arhivi "Saveznog geoloSkog zavoda" u Beogradu) dosegnuta je najveta dubina s podzemnim rudarskim radom u Vrgorcu. Najdublie vertikalno okno nalazi se u reviru Paulina, dubokoje 55m, dok dubina "vjetrenog" ili zratnog okna na rudnom polju Aleksandrija iznosi 40m.

Prema S i n k o v c u (1957) na podruEju bivSeg asfaltnog rudnog tijela "Aleksandar" (prije zvanog "Aleksander" i "Aleksandrija") postoje rezerve B kategorije asfaltne bre& od 45260t te C1 kategorijc od 30000t i to unutar i izmedu "vjetrenog" i popreEnog okna. Sinkovec pretpostavlja da je na podrucju nekadaSnjeg revira "Aleksandar" bilo izvadeno 50000 t asfaltne breEe. On zakljutuje da i na podruEju rudnih polja "Paulina" i "Marija" postoje zalihe asfaltne breCe, no ta mu podruEja nisu bila dostupna istrazvanju. BilanEne rezerve bituminoznih, odnosno asfaltnih stijena su utvrdene 86 300 t (A kategorije 16400 t, B kategorije 25100 t i C1 kategorije 44800 t) s prosjetnim sadrhjem 10%-18% bitumena. Procjenjene su rezerve hk i 340000 t sa 7,2% bitumena s time da 60% rezervi ima 12% bitumena (P a t r 1 j, 1975). Pitanje procjene veCih rezervi povezano je s teSkoCama u usmjeravanju budutih istrativanja, jer su rezultati prije zapotetih istrafnih buSenja vrlo skromni.

Kod Vrgorca je postojao pogon za preradu sirovine. Sastojao se od drobilane, mlina i postrojenja za pripravljanje mastiksa i izolacijskih plob. U proSlosti s dalmatinskim asfaltom prekriveni su mnogi mostovi, terase, izolirana skladiSta, rezervoari i dr. u Europi. VrgoraEkim je asfaltom 1886. asfaltirano nekoliko kristalizacijskih bazena soli u Stonu, od kojih je Sv. Mundo joS pedesetih godina XX. stoljeta bio gotovo neoSteCen. Njime je takoder asfaltiran najveCi dio Sarajeva (An o n i m u s, 1932).

U ViniSeu prirodni je asfalt eksploatiran 1668. (sl. 6) ali i 1628. (B a r b a r o, 1670, S o 1 d o; 1978), a pretpostavlja se i ranije (9 e b e E i C, 1984), jer je prirodni bitumen u srednjem, a dijelom i u novom vijeku rabljen za bitumenizaciju drvenih brodova. Dali je koje od naSih najstarijih lefiSta asfalta bilo poznato u doba h~atskihvl adara, poglavito za kneza Domagoja (IX. stoljeCe), i kralja Zvonimira (XI. stoljete), kada smo raspolagali sa snatnom ratnom drvenom flotom, mo2e se (ne- )pouzdano hipotetizirati. Prema usmenom prioptenju pok. kolege H a n i c h a, ViniSCe je mogla biti luka za popravak brodova, jer je pregledavajuki fotograme u moru viniSkog zaljeva primjetio ostatke stupova za privez brodova. a nalaziSta u ViniSCu su blizu mora. Kako su najstarija nalaziSta prirodnog- bitumena na BraEu i Ciovu bila neznahjna to su nalazigta u ViniStu mogla u daljoj proSlosti imati odgovarajute znaiknje, tim vise Sto se umjetna paklina @atran) ne s~Ominje statutima Bra& i Trogira, kao Sto se u srednjem vijeku, a i kasnije spominje u statutima otoka KorEule i Hvara, gdje se paklina pravila od smreke i jele jer tamo u proslosti nisu nalasista prirodnog asfalta a potrebe za umjretnim bitominum bile su znatne za korculansko hvarsko i venecijansko brodogradiliste (Pederin, 1991)

Vlasnici .su GiniSkih nalaziSta bili Tronirska 1 biskzkpoa, prema kojem je autor nalaziSta na-brdu iznad ViniSh nazvao ViniSCe- Biskupiia (S e b e C i 6, . . 1984) i Tqhka beneaWimka opatija (vink~e-opatija, $ e b e C i C, 1984). JoS 1670. na opelaciju trogirskih biskupa "Vijete desetorice" zabranilo je rudarskim poduzetnicima aktivnost na brdu iznad ViniSCa, jer su uzurpirali zemljiSte Trogirske biskupije. Slitni pokuSaj je uCinjen pribliLno 175 god. kasnije nakon obnavljanja rudarske aktivnosti u ViniSCu - Opatiji :' . kada je nasljednik benediktinske opatije iz Trogira, Splitsko sjemenigte, traZilo zaStitu kod trogirskog suda, koji je zabranio odvoz asfalta iz ViniSCa u Veneciju, dok poduzetnik barun Rotschild nije kupio Cestice zemlje gdje se nalazilo naladte. Uz nalaziSte ViniSCe-Opatija njemaEki inienjer Hermann, , opunomoknik baruna Rotschilda, postavio je nekoliko rnlinova (S 1 a d e-S i 1 o v i C, 1939) za sitnjenje asfaltnog vapnenca te kotao, odnosno ped za zagrijavanje i "topljenje" bitumena, koji se potom cjedio u batvice, ili su iz crne kaSe pravili mastiks pogak, te kao poluproizvod ili pak samo kao sirovinu transportirali jedrenjacima od 1840, a pretpostavlja se do konca XIX stoljeh, u Veneciju i dr.

U ViniSCu je, po B a u E i k u (1943), bila prva hrvatska tvornica asfalta, koja je prestala radom prije I. svjetskog rata. ViniSki asfalt, osim Sto je izvahn zajedno s vrgoraCkim i Skripskim (M a r s c h a 1 1, 1856) u Veneciju, a i drugdje u Italiju, zatim Austriju, Prusku i dr. (T a m b u r i n i, 1852), rabljen je i u Dalmaciji za asfaltiranje sMadiSta, terasa, podzemnih prostorija i dr. SaCuvan je ugovor izmedu E. Hartunga, poduzetnika iz ViniSCa i Financijskog ureda Dubrovnik sklopljen 5.VII1.1874. za asfaltiranje bazena soli Sv. Frano (Francesco) povriine 845 kvadratnih klaftri, a debljine 4-5 cm. Kasnijim ugovorom od 25.V.1876. Hartung se obvezao asfaltirati kristalizaciijski bazen "Mondo" sliCnih dimenzija, t.j. 870 kv.klaf.(3130 m2), a za Sto je nakon primopredaje asfaltnog bazena naplakeno sveukupno 5220,91 fiorina (Arhiv S 1 a d e - 5 i 1 o v i C, Trogir).

Nakon 11. svjetskog rata na Biskupiji procjenjene suzaliheod10000t(Sila i Sinkovec,1955)do 25 000 t (G e m b a C e v et al., 1956), a istrafnim buSenjem izraCunate su bilanCne rezerve od 100 206 t (3 e b e C i C i T r u t i n, 1985) i to B kategorije 97 461 t i Ci kategije 2745t. Potencijalne (C2+D1) rezerve iz tzv. "sjeverne zone", gdje nije buieno, procjenjene su 50 337 t, tako da se svih bilanCnih i izvanbilantnih zaliha procjenjuje 175 OOOt uz stupanj iztraZenosti od 69%. Utvrdena je vrlo sloZena grada najveCeg bituminoznog tijela. To je nepravilno masivno do bankovito tijelo debljine 0.10m-26,20m (Sl. 7). Srednji sadrkj slobodnog toluen - bitumena najvekeg bituminoznog tijela iznosi 3,05% (79 analiza), a gubitaka Zarenjem na 550°c, s kojim je procjenjen sadrfaj kerogena i vezanog bitumena, je 0.58% (76 analiza). ProsjeCni ponderirani sadriaj slobodnog bitumena za nabuseno podruqe iznosi 2,29% (130 analiza), a gubitka iarenjem 0.65% (130 analiza). Ukupno za ViniSCe-Biskupiju srednji sadrhj bitumena (181 analiza) je 2,00%, a gubitka hrenjem na 550'~ 0,76%. Sveukupno iz dosadainjih 213 analiza bitumena srednji sadriaj iznosi 2,24%.

Bitumen se nalazi u porarna razlitite geneze u senonskim biogenim vapnencima, preteko u biomkuditima i bio@Seude>sparmditima, Gg-PpWw-Pp-Gg vapnenaCke sekvencije, koji se odlikuju boljim kolektorskim svojstvima u odnosu na podinske i krovinske vapnence-biomikrite. Osim istrafnog buSenja (34 istrahe buSotine dubina 20m-66,8m) provedena su i rudarsko-geologka istrativanja raskopima, potkopom te produbljenjem starog okna. Od starih rudarskih radova istiCu se dvije "min(j)eren povezane potkopom te jedno istrafno okno. Iz navedenog moZemo zakljutiti da je na Biskupiji otkopan tek mali dio zaliha.

Bituminozno nalaziSte ViniSke-Opatija je dubinski kop (Sl. 8) dubine 15 m, otkopavan u tri nivoa, a s najdubljim nivoom, gdje je dosegnuta razina mora. Zbog blizine mora i obiteljskih kuda ne sugerira se na tome podruCju obnavljanje istrafivanja. Bituminozni vapnenci su po tipu biomikriti (w), a sadr2e 3,04% bitumena (4 uzorka).

Od trogirskih bituminoznih nalaziSta, osim ViniSb, znabjni su bituminozni gornjokredni vapnenci Balova u Primorskom Dolcu i bituminozni gornjokredni dolomiti Ninkvib Lokve u RadoSiku. Prvo se nalaziSte spominje u proSlosti pod nazivom Suhi do1 (S c h u b e r t, 1909), a joS ranije tj. 1804. kao Suhi Dolac, Sto je stari naziv za Primorski Dolac. To je plih manji povdinski kop na padini brda (sl. 9) prozvan u narodu Paklinka, dok je drugo manje nalazste u RadoSiCu otkriveno kasnije (S c h u b e r t, 1909). Sve ostalo su manja bituminozna nalaziSta ukljuCuju6i i ona na Ciovu, koje je u svome putopisu vrlo detaljno opisao F o r t i s joS 1774. (sl. 10).

Na F o r t 1s o v opis "rudnika smolastog asfalta" na zapadnom rtu Ciova prvi je reagirao nepoznati izvjestitelj Marije Terezije (S o 1 d o, 1978), koji je za tu "pojavu"pakline napisao (pribliZno 1776.) da je odlibe kvalitete, ali da se moZe sakupiti tek nekoliko libara, tj. dvije do tri kile (N o v a k, 1962). P e d e r i n (1991) pretpostavlja da je to tajno inj&& napisao neki bvjek iz blizine Wilhelma Boltsa, Nijemca rodena u Londonu, a Cije su zasluge bile i osnivanje "Wtm-Oshikche HandeIskompanien 1776. u Trstu. Nepoznati izvjestitelj prigovorio je F o r t i s u Sto je krivim informacijama o koliCini rude mletatkoj vladi sugerirao da se upusti u eksploataciju, Sto to ona ipak nije uEinila. Zatim izvjestitelj piSe da joS pondto pakline ima na jednom mjestu kraj Skripa na BraCu, u jednoj uvali prije Vrgorca (nalaziSte Kotezi) te nedaleko Sinja (Dipalovo vrilo) i jugozapandno od Sinja.

U neretvljanskom podruCju u podnoZju brda Rabe tj. u Slivnu Fortis spominje takoder rudnik smolastog asfalta, s pripomenom da ga nije posjetio. Rudnik smolastog asfalta Sv. Ivan u "PuCiSCu" na Brah F o r t i s nije takoder naSao, a dr. Bajamonti mu je pokazao uzorak s tog lokaliteta. F o r t i s je konstatirao da su fosili u tom asfaltnom kamenu drugatiji nego Sto je vidio u drugim asfaltnim nalaziStima u Dalmaciji ( F o r m a l e o n i , 1 7 8 6 ) .

Na s'evernom dijelu otoka B r a E a, nedaleko mjesta 4 krip nalazi se napuSten rudnik (sl. 11) asfalta tj. bituminoznog dolomita koji je otkopavan izmedu 1750. i 1874. Glavni dio rudnika 8ni nekoliko jamskih dvorana u dolomitu koji je dijelom bio obogakn bitumenom (sl. 12). U niskopu i boEnim hodnicima nalazi se samo mjestimicno malo asfalta i to u tankim slojevima ili uprskanjima. Stoga je i razumljivo zaSto se odustalo od rudarenja. Ni naknadno obnavljanje rudarske aktivnosti s dva potkopa u istoEnom dijelu nalazsta, kao i plitko istrabo buSenje, nisu dali pozitivne rezultate. Od starijih rudarskih radova zabiljebno je na istoenom naladtu nekoliko raskopa.

Iz Skripske rude ekstrahiran je bitumen uglavnom u dvjema okruglim pekima. PeCi su razrulene, a jedna je i zatrpana. Zapadni dio nalaziSta je bogatiji bitumenom (2,63%-9,40%) u odnosu na istoEni (0,09%-3,19%). Na temelju 26 analiza bitumena iz 1968. izraEunan je srednji sadrbj od 337% bitumena, a s 50 analiza medu kojima ima i analiza uzoraka bogatijih s bitumenom izraCunan je sadriaj od 5,94% bitumena (K a n a j e t et al., 1995).

Skripski bituminozni dolomiti te tragovi bitumena u rudistnim vapnencima, tj. braCkim "mramorima", prema J e r i n i C u et al. 1994) pripadaju dijelu PuEiSCa formacije. Kerogeni stromatolitni vapnenci Mirce i Brizija na BraEu pripadaju dijelu Sumartin formacije (G u S i C i J e 1 a s k a 1990).

Osim u rudnom polju "$knPn bituminozni je dolomit otkopavan znatno kasnije u rudnom polju "Brap u Pod Badnju. Bituminozni se vapnenci nalaze nedaleko PuEiSea i u Sv. Martinu (Sumartinu), u rudnom polju "Dalmacija", dijelom kod Splitske i Mirce. Kerogeni vapnenci, odnosno "fosilni ugljeni" otkopavani su u rudnim poljima "Wlhelm" juZno od Mirce, "Gustav" i "Herman" na sjeverozapadu Bra&, te u KolaEima jugozapadno od NereZiSCa i u rudnom polju '%lustrijan, juZno od Dratevice na jugozapadu Bralla. Kerogenih vapnenaca ima joS kod Bola, Zekva, Postira i Sutivana (J e 1 a s k a et al., 1983).

Sve rudarske koncesije (T o m a S i C, 1949) dobivene za Austro- Ugarske bile su na snazi i za Kraljevine Jugoslavije, Sto ukazuje na nekadaSnji interes za ekaploataciju i primjenu kako biturninoznih tako i kerogenih stijena. Potrebno je istaknuti da navedena nalaziSta nisu detaljno geoloSki istrakna, bez obzira na stupanj njihovog rudarskog istrafivanja, pa je tdko procjeniti njihove rezerve.

Sredinom XIX. stoljeCa proizvodio se u Skripu prirodni asfalt s 9%-10% bitumena, te izvozio teretnim jedrenjacima zajedno sa vrgoratkim i viniSkim asfaltom u Veneciju (M a r s c h a 1 1, 1856), gdje je preradivan kao sirovina ili poluproizvod. Proizvodi dobiveni preradom prirodnog asfalta iz Dalmacije bili su prikazani na PariSkoj izloZbi 1855., gdje je bilo prisutno 30 izlagata iz Francuske, Austrije, Bavarske, Spanjolske, Portugala Kanade i Meksika.

Povlasticu za kopanje braekih, a i viniSkih asfalta dobio je u drugoj polovicu XIX. stoljeh Heinrich (Enrico)Hartung, poduzetnik iz Trogira, podrijetlom iz NjemaEke. To se obznanjuje u dozvoli za rudarsko istrazivanje temeljeno na austrijskom rudarskom zakonu iz 1854., a odnosi se na kapetaniju Split i Sinj, a koju je H a r t u n g . pribavio 1873. (sl. 13), te produZio 1874. SaEuvan je njegov certifikat iz 1879. za slobodno istraZivanje (asfalta) u ViniSCu.

Prema N i k o 1 i C u (1900) bratka nalazsta u Sv. Martinu, Mirci, Skripu, Splitskoj i NereZiSCu istraZivali su rudarski inknjeri "Steinkohlen-Gewerhchaft-av" et 1840. god. Od svih nalaziSta najviSe je obekavao Skrip. No, unatoE visokoj proizvodnji od 120.10~ bE.c (6735 t) u ktiri godine Skripski je rudnik doSao u teSkode, pa je banka prepustila rudnik privatnicima. Godine 1873. rudnik je zakupila frncuska "L' Asphalteine, Societe Anonyme des Asphaltes et des Bitumes de L' Adriatique", ili "Asfaltena, DioniEko (Anonimno) druStvo za jadranske asfalte i bitumene", iz Pariza od E. Hartunga iz Trogira. Naime, iz dokumenta kraljevskog i carskog biljeZnika dr. A. Hochkoflera iz Trsta od 15.1.1874 moZe se zakljuEiti da se Hartung obvezao prodati "Asfalteni" koncesiju za istraZivanje asfalta. Kako Hartung vjerojatno nije potpisao ugovor, jer ga se opominjalo, pretpostavlja se da je "Asfaltenan uvidjevSi sloZenu rudarsko-geololku situaciju u Skripskom rudniku odustala od kupnje prava prvenstva koriStenja asfaltne rude, a za iskopanih 400 t moli Hartunga da asfalt ostane uskladsten, dok se nade kupac (sl. 14).

Od asfaltnih nalaziSta na BraEu S o h 1 e (1900) najviSe opisuje Skrip, Cija se debljina dolomitnog "pijeska" bogatog s asfaltom maksimalno procjenjuje oko 20m.

Prema P e r i C i C u 1980), G.Billio, jerojatno podrijetlom naS BiliC (op. & ewita) geolog-istraZivaC, ali i rudarski poduzetnik, otkrio je ugljen kod Skradina, na Promini (Siverid, Dubravice i VeluSiC), a fosilni ugljen na Bra& (Smirk), gdje je otkrio i paklinu. Prema D i e d i (S o 1 d o, 1978) Billw je dobio s D. Stressijem 1782. investituru vadenja fosilnog ugljena u cijeloj Dalmaciji Tako je Billio p o b iskapati fosilni ugljen, tj. kerogene stromatolitne vapnence na zemlji Smirk (kod Mirce, op. Sebe~iCa) dva kilometra jugoistoCno od Sutivana, odakle su ih odvozili teretnim jedrenjakom u Rafineriju S e r a u Rijeku. U pismu svome posredniku P.BergaliCu, Billio istik da je poktkom 1791. god. bilo u Sutivanu uskladiSteno oko 12 vagona, t.j. 114t "ugljena".

Godina 1784. i 1785. ~.$imunovic'i ~ . ~ i m u n te I-Srempic' i M.Beros' dobili su od Magistrata dozvolu za iskapanje pakline iz triju "rupa" u Martinici ili SmriCi.

Godine 1781. A.Lovrid iz Sinja zajedno sa KCelio-Cega (S o 1 d o, 1978) dobili su dozvolu za vadenje crnog asfalta na rtu Sv.Ciprijana kod Trogira uz plahnje desetine.

0 pojavi mrlja smole (kao katrana) na brdu Humu nedaleko od benediktinskog samostna i crkve kod KomiZe na Visu izvijestio je pismom 1782. god. Ekonomsko druStvo u Splitu lijeCnik Barbijeri, te istakao da narod zove to mjesto Paklenica i da se tu kopa katran (tj. paklina), koji se rabi za mazanje ribarskih brodova (2 g a 1 j i 6,1984).

Godine 1786, dobila je obitelj M o s c a t t i pravo kopanja asfalta kod Siverida, medutim zbog velikih gubitaka odustala je od daljeg kopanja po isteku dozvole (P e r i C i 6,1980).

Nakon propasti MletaEke Republike, Istra i Dalmacija uSle su u sastav Austrijske Monarhije, pa je njena Hofkammer (Dvorska gospodarska komora) registrirala do tada poznato rudno blago na navedenom podrueju. Tabelarno izvjeSCe ovih istra2ivanja (sl. 15) naanili su P a n t z i G a r a p i c s (1804), Sto gotovo poslije 190 god. spominje E r c e g (1992). Ukupno su opisali 26 lokaliteta od kojih je 7 sa zemnom smolom i to w ~ ~ ~lstrbi, su~hi ~~ n Vrgorac, Slivno na Neretvi, te Ciovo i Braf (Mirca i NereZiSk). Zemna smola, odnosno bitumen nalazi se u vapnencima, a ponegdje u vapnenazkim laporima. Za ve6inu su pregledanih lokaliteta P a n t z i G a r a p i c s utvrdili da nisu vrijedni; nadalje za nalaziSte Slivno su konstatirali da ne sluZi kao korisni prirodni produkt, dok su za nalaziSte Vrgorac pretpostavili da ima malo nade za izddniju eksploataciju, Sto je kasnije demantirano. Za braEka nalazsta su istaknuli da su iztrazivana veC za venecijanske vladavine.

Od mosorskih bituminoznih leZiSta prvo se spominje leute u Dolcu (H a u e r, 1850), odnosno u Krivom Dolcu (S c h 1 e h a n, 1851), gdje su bili izvodeni veCi rudarski radovi, Eiji su troSkovi od 1849. do 1851. zapisani u tekukm rahnu (sl. 16).

Iz tekukg rahna Sto je naEinjen izmedu "Direction der adriatischen Asphalt Werke zu Venedig" i Grossa(1852) iz Splita vidljivo je da su ukupni primici iznosili 15748,52 fl., a izdaci 17519,2 fl. U izdacima navode se meUu inim i oni Sto ih je naCinilo Rudarsko nadldtvo na BraEu (1364,19 fl.) i ViniSCu (530 fl.) te u rudarskom pogonu u Vrgorcu (300 fl.). Najvek troSkove uEinilo je "Upraviteljstvo tvornice za preradu asfalta u Veneciji" tijekom dijela 1849., u 1850. i u dijelu 1851 god. na mosorskom asfaltnom podrucju ukljuCujuCi Krivi Dolac ( 4 6 7 fl.).

Potom su R i t t e r et al, (1855) pisali o jamama sjeveroistoEno od Splita, vjerojatno na dolaEkom podrutju, koje su nazvane "Alleanza" (Savez), "Fedelta" (Vjernost), "Fuiucia" (Pouzdanje) i i"~M adonna delle Grazie" (Gospa od milosti). Kasnije K e r n e r (1916) opisuje asfaltna nalaziSta i leZi3ta i u Donjem Dolcu: Okruglicu, PutiSCa Stan, kasnije nazvane "Staje", Na Privaj, zatim Gornja RoSca i Akrap, a kasnije (1919.) Aupu, Kozicu, DreZnicu, Stikovo, RadoSiC i dr.

Rudno polje "Fedeltan u Krivom Dolcu podijeljeno je 1847. Cerineu i Grossu a potom vjerojatno prodano 1850. Rougieri . Od 1930. vlasniStvo je "Ruda" dd. u Splitu. Obli2nja rudna polja "Vkgirzia" i "Paul" u Okruglici bila su od 1904. vlasniStvo "Bergwerkgesellschafra" iz Hamburga, a od 1930. bili su u zakupu ing. Grochowalskog, I nekadaSnjeg upravitelja vrgoraEkog rudnika

U Gornjim RoScima (Donji Dolac) i Akrapu (Bisko) koncesiju za istrafivanje, prema usmenom prioptenju mjdtana, imali su VdoviC i Sisgoreo iz Splita. U Dolcu Donjem, t.j. Krivom Dolcu rudarska l@?id istraZivanja je financirala i Banska vlast Banovine ' . wtmqry-6- Hrvatske (sl. 17).

U Gornjim RoScima bili su sprovedeni istrahi radovi raskopima te manja eksploatacija dubinskim kopom. Istrafnim je buSenjem utvrdeno da se bitumen nalazi gornjokrednim, ali i eocenskim vapnencima i tektonskim brehma. Nadalje, utvrdena je dubinska VeZa i~medu bliskih povrSinskih Sinjizdanaka. Debljina je bituminoznih tijela prosjeCno 17,7m. Sadrhj je bitumena uglavnom viSi u povrSinskim izdancima nego u nabuSenim . . naslagama.Kvalitetnija je sirovina debela samo 1,5-6m, a tek izuzetno 16m. Za sve nabuSene naslage srednji sadrhj bitumena iznosi 0,76% (70 analiza), dok je za jednu buSotinu viSi, tj. 1,62% (27 analiza) (5 e b e C i 6, 1981.). Srednji sadriaj procjenjene netopive or anske tvari je 1,88% (70 analiza iz 6 buiotina) (! e b e C i C , 1Y7.). Prema odnosu slobodnog bitumena u ukupnoj organskoj Wari u gornjokrednim vapnencirna uktaliji su slabo . kerogeno-bituminozni vapnenci, a u paleogenim vapnencima slabo bituminozno-kerogeni vapnenci i slabo kerogeni vapnenci. Projenjeno je da je samo 10% rezervi kvalitetnija sirovina, tj. 26285 t (3 e b e C i C, 1977.).

U sklopu prikaza bivSih jugoslavenskih, ukljuCivSi dalmatinske asfalte A b r a h a m (1960) izdvaja vrgoraCke, bratke i moroviCke asfalte sa starim analitiekim podacima, dok u crnogorske krivo I uvrStava ili mu je tako sugerirano, dubrovaEke, 1 viniSke, Ciovske i suhodolske (sjeverno - trogirske) ' asfalte, te asfalte izmedu DrniSa i Knina. Abraham . . piSe da moroviCki slabo dolomitizirani vapnenci iz okolice Sibenika sadrZe 10-15% asfalta, dok viniSki kristaliEni vapnenci 9,2%, a dubrovacki (vjerojatno gnjilo-ratski) vapnenci 13,9%. - Naziv asfaltnog lokaliteta MoroviC ili Morovice vjerojatno potjete od imena sela Mokro na granici izmedu Sibenskog i trogirskog kotara (S t o S i C, 1941), a pripada Zupi Danilo-Biranj.

Da je nalaziSte asfalta u Gnjilom Ratu na p0lu0t0ku PeljeSc~ bilo iStraZivan0, ako ne i eksploatirano u XIX. stoljdu, dokumentirano je analizom bitumena od "vjerojatno" 25% (T r i n k e r, 1868). Prema kemijskim analizama (J o h n i E i c h e i t e r, 1901) asfaltni vapnenci "Poljica" (D. Dolca) sadrie 32,94% bitumena, a Vrgorca 31,05%. Kasnije je u vrgoraaom asfaltu odredeno 16,32% bitumena ( E i c h l e i t e r i Hackl,1920).

U Kozici su istraZivani gornjokredni bituminozni dolomiti joS prije I. svjetskog rata. U njima su locirana 2 niskopa po 25 m duiine. Sadrbj bitumena varira od 0,90%-11,20% (x=3,87%, N=20), a debljina biturninozne zone od 1,5 do 3 m.

Kao najznatajnije nalaziste asfalta u nas S c h u b e r t (1909) navodi Vrgorac, koji je ved poznat u XVIII. stoljeku, zatim Kozicu, Dolac, RadoSiC, te Suhi dol, Prapatnicu i dr., a na Brah: Mirca, Pui%Ce, Sv. Martin i Skrip. To su sve gornjo kredna lezista i naladta, od jurskih naWta navodi Stikovo, Kijevo i dr., a od eocenskih Peljdac i ciovo.

Na kraju, ostaje joS nerjdeno pitanje podrijetla okruglastih sekundarnih nakupina pakline (bitumena) u naplavinama na Paklenim otocima. Za sada je neutemeljeno uobitajeno povezivati izdanke pakline sa nazivom Paklenih otoka (2 g a 1 j i C, 1994), jer je kopanje pakline na Paklenim otocima nepoznato hvarskim ribarima. einjenica je da su ribari rabili okruglaste naplavine veliCine jabuke, a ponekad i v&, i da se one nalaze rasprSene po uvalama, znatno vise na sjevernoj strani otoka nego na juinoj. Prema usmenom priopnju N. G a z z a r i a, dipl. ing. brodogradnje, podrijetlom sa Hvara, "grudaste" naplavine su donosene morskim strujama i to s maestralom sa sjeverozapada (ciovo i/ili ViniSCe-Opatija) ili jugom s (jugo-)istoka (iz doline Neretve, ili bli2e s istoCnog dijela Hvara). Osim toga podrijetlo ovih naplavina ne iskljutuje se povezati s nekim manjim podmorskim nalaziStem bitumena ili nafte, Sto bi trebalo ispitati.

IstoCno od Novske, a osobito izmedu potoka Paklenica (sl. 18) i VoCarac, registrirano je vise nalaziSta bituminoznih slabovezanih pjdknjaka, odnosno pijesaka (5 e b e C i C i B u 1 i C, 1983). Debljina im je milimetarska do maksimalno nabuSenih 1,35 m. Na temelju geoloSkih profiliranja, raskopavanja, zasjecanja i prospekcijskog istrdnog buSenja konstatirano je da su bituminozne naslage volumno podredene, jer se izmjenjuju s jalovim naslagama. Tako u buSotinama omjer jalovine i rude varira od 4:l do 151. SadrZaj bitumena u neogenskim Banatica-naslagama Paklenice varira od 0,10% do 10,12% (x= 3,76%, N=37).- GeoloSke rezerve izmedu 3 buSotine su procjenjene na 50000 t, a predvidaju se da s u i v e C e ( 0 r e S k i i D u r & a n o v i C , 1 9 8 3 ) . S obzirom na tankoslojevitost i ustrmljenost bituminoznih naslaga, te nepovoljan njihov odnos prema jalovim naslagama, a uz to i neizbjeku devastaciju Suma, ne sugeriraju se dalja istraZivanja na tom podruCju.

Prema A n o n i m u s u (1920), sjeveroistoCno od BaCidola (sl. 18) prema Cerniku nadene su priliCno laka nafta i smola u nekoliko rudarskih okana. To je ponukalo grupu poslovnih ljudi: grofa Erdiidya, baruna Gmttschreibera i sisazke bgovce da sagrade tvornicu mineralnih ulja radi dobivanja kolomasti za podmazivanje kola i kotija.

U Paklenici kod MikleuSke (sl. 18), gdje je takoder podignuta 1860. tvornica kolomasti i kod Volodera na padinama MoslavaCkog gorja nadena je zemna smola u tercijarnim sedimentima. U vetem nalaziStu u Paklenici dnevno se eksploatiralo vise centi zemne smole i ulja pomjdanih s vodom iz okana dubine 45-60 m. Kasnije je, 1905., druStvo "Vesta" buSenjem utvrdilo zemnu smolu i na 70 m dubine, a zemni plin i na veCim dubinama. Kod Volodera, 4 km zapadno od MikleuSke utvrdeno je na dubini ktvrtog metra, nalaziSte bituminoznih stijena debljine 4-6 m., iz kojeg kaplje tamnozelena nafta.

Kod Velikog Poganca (sl. 18) buSenjem su u Skriljavcu otkrivene gnd' ezdaste nakupine zemnog voska, koji se topi na 70 C. To je nalaziSte otkriveno nakon potresa 1882., medutim potom izvedena istrdna buSenja nisu dala pozitivne rezultate.

U svom "MineraloSkom leksikonu" piSe Z e p ha ro v i c h (1859) da se u Hrvatskoj nalazi paklina i u medimurskoj Peklenici (sl. 18) i to u tercijarnom pijesku na obali jednog potoka i u jednom 3,9 m dubokom oknu. To je ponovio i R a u k a r (1932) navodeCi da je tam0 1836. dobivano tamnosmede zemno ulje za kolomaz.

Kerogena leZiSta i nalaziSta

"Uljnin ili kerogeni sedimenti nalaze se u Hrvatskoj na viSe lokaliteta u Dalmaciji, Lici, Istri i dr. (sl. 18). Iz njih se nekada dobivalo sirovo ulje u Rudi kod Sinja i Baljevcu kod BihaCa, a pretpostavlja se i u BruSanima kod GospiCa. Ulje se primjenjivalo u razliEite svrhe: medicinske, energetske i dr. Prema dosaddnjim spoznajama mo2e se zakljuCiti da se najkvalitetnija sirovina eksploatira u Rudi kod Sinja te u Vrelu KoreniCkom i Baljevcu. Istrafivanjem veCine nalazista konstatirano je da se kakvoh sirovine vedine lokaliteta moZe primnjeniti u niskoenergetske svrhe.

Naknadnim istra2ivanjem kerogenih nalaziSta utvrdeno je da je manji dio sirovine kvalitetan, jer se u njima izmjenjuju jalovi i kerogeni dijelovi naslaga. To znatno smanjuje bilanCne zalihe nalaziSta. DosadaSnjim istrafivanjem nisu registrirani debeloslojeviti i izrazitije kerogeni sedimenti.

Od hrvatskih lefiSta uljnih Skriljavaca najznazlajnije se nalazi u Sinju-Ruda, (sl. 19), jer je bogato uljem (30-40%), a rezerve mu se procjenjuju "nekolikon milijuna tona (L u k o v i 6,1936). Drugo lefiSte je Baljevac s vise tankih slojeva do 0,5m, koje je eksploatirala kraCe vrijeme, tj. 1901-1905, kemijsko-farmaceutska firma "G. Hell" iz Troppaua (R u d a r s k o s a t n i S t v o Zagreb, 1893-1901) te iz njega dobivala "ihtiol". "Za pojave uljnih Skriljavacan u Hrvatskoj konstatira E r c e g o v a c (1990) da su na niskom nivou istrafenosti, jer nedostaju podaci o organsko-petrografskim i geokemijskim svojstvima. To se prije svega odnosi na pojave Trlji i Saini u Istri, zatim na PoStak u Lici te na Svilaju i Ruda u Dalmaciji. Smatra da bi "pojave" na PoStaku i Rudama trebalo detaljnije prouCiti, jer im je kerogen sapropelnog tipa.

Pretpostavlja se da je istragivanje uljnih Skriljavaca u Lici zapoCelo u XIX. stoljeCu, jer se njihova prerada obavljala u Baljevcu 1901-1905. Prema prijevodu njemaCkog teksta nepoznatog autora (A n o n i m u s, ?) moZe se zakljuCiti da je za eksploataciju podjeljeno 5 koncesija: "E3aljevac" (vlasnik ing. LPatta, R e i t t e r, 1926;) "Zavalje", "Vrelo", tlLapac" i "Korenica" sveukupne povrSine 51 400 000m2. Za Liku su navedene rezerve od 20 000 000 t.

U Baljevcu eksploataciju donjokrednog "uljnog Skriljavca" pred 11. svjetski rat izvodilo je "LiCko rudarsko udruienje" a potom i "Gyrodaln- rudarsko udruZenje iz Zagreba. Postojala su 4 manja radiliSta na kojima se radilo poMSinskim kopom, ali i kombinacijom niskopa i preCnika dufine nekoliko metara. Ekstrakcija ihtiol ulja obavljala se u 8 retorti na temperaturi od 520°c/3 h iz zdrobljenog uljnog Skriljavca velicine oraha. Dnevna produkcija ulja iz baljevaekog leZiSta bila je 1,6Ot-1,92t ili maksimalno 700tJgod.

Iz zavaljskog, tj. suhodolskog leZiSta, koje je eksploatirano kombinacijom zasjeka, potkopa i hodnika, pridobivano je 0.2t- 0.8tJdnevno odnosno 180 t ulja J god. (1947.), a iz medudrafkog ili bjelogredskog 0.4t-0.5tJdan. Nedostaju podaci o produkciji iz koreniCkog nalazigta, gdje su istraZni radovi obavljeni s d v ~po tkopa dufine 12m i 6m. "Skriljavci" su preractivani u tvornici ulja u Baljevcu, koji je nakon 11. svjetskog rata pripao Bosni i Hercegovini. Stara je destilerija poruSena u 11. svjetskom ratu, ali je nakon rata obnovljena te radila krak vrijeme punim kapacitetom. Eksploatacija Skriljavaca provodila se povrSinskim kopom, a otkopavalo se i u Hrvatskoj, i u Bosni i Hercegovini unutar ihtiolske dolomitne zone.

U Vrelu Korenitkom su dva nalaziSta gornjojurskih kerogenih stijena: ZuboviCa Draga i Mrsinj Grad (Milanovita Draga), koja su rudarski istraiivana za Austro-Ugarske na prijelazu stoljeh. Kratko su vrijeme eksploatirana nakon 11. svjetskog rata, do zakljuCno 1949. god. Prije deset godina obnovljena su geoloSko-organsko-kemijska ispitivanja, kako koreniCkih tako i zavaljskih, nalaziSta kerogenih stijena (s a b a n i 5 e b e C i C, 1984,s e b e C i C et al., 1990 b i dr.), a ispod Mrsinj Grada obavljeno je prospekcijsko istraZno buSenje (S t o i s a v 1 j e v i C et al., 1988). Utvrdeno je da se sadrhj organske tvari mijenja vertikalno i lateralno (0.06%-6.57%, izuzetno do 68,42% ~"kerogencu",a Sto se moglo ilustrativno uotiti i po donjim toplinskim vrijednostima nabugenih kqogenih stijena Mrsinj Grada (od 0 do 17.401 kJ/kg, x=1986, 10 kJ/kg; 52 uzorka iz 7 busotina, e b e C i C et al. 1989).

BuduCi je energija znatna stavka (40 %) u proizvodnji cigle uCinjen je 1989. pokuSaj utvrdivanja tehno-ekonomske ocjene prve industrijske primjene "uljnih Skriljavaca" u Hrvatskoj: u sirovinu za proizvodnju cigle u ciglani u Zagrebu mijeSano je 5% pa 10 mas.% "uljnog Skriljavca", tj. mase kerogenog dolomita i kerogenog Certa iz leiiSta Zubovita Draga bod Vrela KoreniCkog (sl. 21).

Preliminarnim industrijskim ispitivanjem s (3%-5%) "uljnog mtriljavca" s donjom toplinskom vrijednosti 1421 kJ/kg, te s industrijskim ispitivanjem s 10% "uljnog Skriljavca" s donjom toplinskom vrijednoSCu 1250 kj/kg proizvedene su Suplje blok cigle 250x190~140m m marke 10 i 15 (JUS D1.015). Ekonomskom analizom temeljenom na cijenama iz sijeCnja 1988. izratunato je da je "uljni Skriljavac" kao dodatak rentabilno koristiti kada bi imao donju toplinsku vrijednost 3767 kJ/kg (3 e b e ZI i C et al., 1989). Tome bi zadovoljio tek manji odabrani dio "uljnog Skriljavca", pa se prekinulo s rudarsko-geolos'kim istraiivanjima. Tek kraCi transport do bliie ciglane, npr. u PeruSiCu, moZda bi zadovoljio primjenu nife energetskih uljnih Skriljavaca.

Na PoStaku u Lici kerogene su naslage registrirane na juZnom, zapadnom i sjevernom krilu brahisinlinale koju je J a k i C (1984) fotogeoloSki okonturio. PruZanje kerogenih naslaga je 17km, a debljina im je 30(-50)m. To su gornjojurski kerogeni vapnenci - biomikriti a rjede fosiliferni mikriti i ertovi u izmjeni, te dolomiti. Samo su podruCja DimiCi i Vagan neSto bogatija s organskom tvari. Tako npr. sadrbjjCorg u uzorcima DimiCa varira od 1,93% do 7,12% (x=4,38% za 19 uzoraka).

Rezerve prema T a n c i g u iznose 2 000 OOOt (C u b r a n i C-A j d u k o v i C, 1981) i to na podruCju RastiCeva, odnosno Mijine Glave gdje su 1949. obavljeni istraZni radovi radi otvaranja povrSinskog kopa. Na bogatije predjele s organskom tvari i to Lisinu (DimiCi) i Viline PleCine (Vagan) ukazao je veC P e t u n n i k o f f (1938), te procjenio prevelike rezerve bituminoznih Skriljavac. za cijelo nalaziSte (900 000 000t). PoStak je veliko nalazidte, ali uglavnom niskokvalitetne sirovine.

Kerogeno nalaziSte u Vaganu, zaseoku G. TiSkovca u Lici, poznato je veC od prije 11. svjetskog rata (P e t u n n i k o f f, 1938). To su gornjojurske LemeS naslage, uglavnom slumpirani i laminirani dolomiti s kvarcnim nodulama. Sastavni su dio kerogenih leda kojih se duZina procjenjuje na 10-12m. U le6i ima i kerogenih siltita s radiolarijama. Slobodnog bitumena ima viSe u dolomitu (5,24%) nego u siltitu (0,67%). Ukupno organske tvari u analiziranom dolomitu ima 49,38%.

I. Ulrich, mjernik i rudarski poduzetnik iz Sv. Ju rja u Stajerskoj bio je prijavio istrafivanja i rudarenja u Lici, pa je dobio rovne i samorovne dozvole u GospiCu (BruSani, Medak, Smiljani), PeruSiCu (Kosinj), Grahcu, Donjem Lapcu i Srbu. Nakon odredenog vremena (12.X1.1882.) OreSkovid iz "Kraljevskog rudarskog satniStvan iz Zagreba poslao je upit "Kraljevskom kotarskom sudun u Zagrebu da po dotihim opCinama izvidi, da li je Ulrich rudario? Takoder je, istog datuma, poslao upite i "Kraljevskom poreznom uredun u GospiCu, Grahcu i Ototcu da izvidi je li je Urlich platio samorovne pristojbe, a poglavito zaostatak za 111. ktvrtinu 1882. god. Iz jedinog saEuvanog odgovora iz Grahca moglo se zakljutiti da tam0 Ulrich nije rudario.

IstraZivanjem fosilne faune u Dalmaciji M a r g e t i C (1952), je utvrdio da postoji vise horizonata "talohih bituminoznih (t.j. kerogenih op. Sebe~ih) stijena" gornjojurske, donjokredne, gornjokredne i tercijarne pripadnosti. Time je osporio starije miSljenje beCkih geologa da porijeklo asfalta treba iskljuCivo traiiti u gornjojurskim plohstim vapnencima. Ambijent tvorbe mezozojskih (kerogenih) naslaga po M a r g e t i C u (1952) je morski, starije tercijarnih naslaga brakihn a mlade tercijarnih jezerski. a h n a z a r o v (1941) veC je ranije uoCio razlike u genezi bituminoznih stijena Bra&, pa uz prirodne asfalte istik i pirobituminozne stijene kako ih kasnije M a r g e t i C (1952), a i potom K r a n j e c et al. (1964) nazivaju, talo2no- "bituminozne" stijene, a nalaze se u dva horizonta, dok se prirodni asfalti nalaze izmedu njih. Za BraCke taloZno- biturninone stijene K r a n j e c et al. (1964) zakljuCuju da su zbog svoje vete plastihosti unutar debelouslojenih vapnenaca sekundarno poremhni tj. mikroborani, rmlcrorasjedani i drobljeni PreteZno se odlikuju finoslojevitom, kasnije nazvanom laminiranom strukturom, u kojoj se naizmjeniCno redaju karbonatni i bituminoni slojevi., U bitumenu je mikroskopski utvrdena izmjena svjetlijih i tamnijih 1istiCavih tvorevina te "nepravilna pjegasta nagomilavanja te sitnije crne toCkice nejasna porijekla" (kerogen, op. e b e C i C a). Uokna je i migracija svjetlijeg bitumena u filice i mreZaste nakupine, ali i u romboedarske pore u dolomitima.

Prema M a r g e t i C u (1952) intenzivno se rudarilo u 1950. i 1951. na BraEu (Brizi i Dujiievo), Dre2nici (Mir/illovii Polje), Biteliiu te u Vrdovu i UniStima. U paleogenim gornjo kozinskim kerogenim vapnencima, t.2. "bituminoznim laporima" Plane (kod Vrgorca) izraden je potkop 120 m i nekoliko plitikih okana. U Antunoviiima su izdubljena dva okna dubine 2-7 m.

Prema Schle(c)hanu (F o e t t e r 1 e, 1851) u krovini glavnog ugljenog podinskog sloja kod Siverida, u jami Barbara, nalaze se bituminozni laporoviti Skriljavci, ali ih autor ne spominje.

Ustanovljeno je da smrdljivi "bituminozni Skriljavac" tj., kerogeni vapnenac iz Kremene u blizini Neretve sadrZi 52,7% pepela. Destilacijom je iz njega dobiveno 23%-26% katranskog ulja (A n o n i m u S, 1873)

U tercijarnim sedimentima otkriveni su uljni Skfiljavci u Rudama i tu je prema T u C a n u (1925) osnovan rudnik 1898. god. Plinara u Splitu rabila je te uljne Skriljavce za dobivanje rasvjetnog plina katrana. Nakon 11. svjetskog rata nakratko su obnovljena rudarsko-geoloSka istraBivanja te dijelom izraCunate rezerve 3,5 milijuna tona s time da su industrijske rezerve procjenjene na 2,3 milijuna tona (S e f, 1956). Proratun dijela rezervi za jdni dio sinklinale temeljen je na rezultatima 4 buSotine te na povrSini 1500m x 500m, a debljini rudnog sloja od 2,4m, pa su izrahnane rezerve od 1800000 m3 sirovine. Analizom 4 uzorka jezgri po Fi@erovoj metodi odredeno je od 6,7% do 18,7% ulja (x= 12,5% ulja). T a k S i C je 1948. za Rudu kod Sinja procjenio ukupne rezerve "ugljena", tj. "uljnih Skriljavaca" na 360000t, medutim, on smatra da je najmanje 25% rezervi izvadeno, pa je ostalo joS 270 OOOt. Po nepovoljnijoj varijanti izratunato je samo 100 OOOt sirovine te je uz izvadenih 25% preostalo samo 75 000t. Navodi miSljenje rudara A. Polaske po kome je ugljeni sloj u rudniku bio debeo oko lm, te da su postojala 4 horizonta koja su povezana niskopom. "Bituminozni Skrilja(va)cn Ruda predstavlja po P e t r u n i C u (1951) "prvoklasan objekt s dobrom amortizacijomn Naime, pri tome je mislio na primjenu "Skriljca" u cementnoj industriji.

Od starih rudarskih radova u Rudama nije ostalo niSta pristupaCno, jer su oni zaruSeni ili zatrpani, kao Sto je ulaz posljednjeg potkopa zatrpan tik uz seoski put (s1.19), a gdje je izmjerena 5m debela zona obogatena organskom tvari u kojoj se uzmjenjuju tamnije i svjetlije lamine. Tamnije lamine su bogate kerogenom, dok su svjetlije njime siromaSnije, ili ga gotovo ne sadrfe. Organska je tvar neuela, pa se ove stijene iskljuCuju iz naftno-matiCnih stijena (S e b e- C i C i E r c e g o v a c, 1983). Na dijelu kerogene zone u Rudama izgraden je sada veliki ribnjak Sto dijelom smanjuje moguCnost eksploatacije. Nadalje, zbog ustrmljenosti slojeva i nedefinirane dubine zalijeganja postavlja se pitanje ekonomitnosti i obnavljanja eksploatacije tog kerogenog lefiSta.

Od kerogenih nalazsta na Dinari, istiCu se ona na Golom Brdu kod Vrdova. Istrafivana su pedesetih godina ovog stoljeh (M a r g e t i C 1952, F i 1 j a k, 1951), a posljednji put su istrafivana prije nekoliko godina (3 e b e C i C i S 1 o v e n e c, 1990). Njihovo znatenje je zasada vise sedimentoloSko, naftno-geoloSko i mineraloSko nego ekonomsko. Oko 200t sirovine preradeno je u tzv. majlerima u Sinju do 1951. i dalo je ulje dobre kvalitete. ~akvodas irovine kerogenih stijena ocijenjena je i po gornjim toplinskim vrijednostima. Tako je utvrdeno, da je kvalitetnija sirovina (od 2500kJkg 4800 kJ/kg) uglavnom vezana za kerogena nalaziSta 2 i 3, tj. za stromatolitne karbonatne stijene.

Kerogeno nalaziSte Trlji u Istri otkriveno je za fiancuske okupacije Istre, a otkopavano po Talijanima s istrafnim oknima dubine 7m i 8m izmedu dva svjetska rata. IstraZivanja su obnovljena tek unazad 10 godina (V u C k o v i C i S r n i C, 1983, S e b e E i C et al. 1990). To su cenomanski kerogeni dijelom stromatolitni, vapnenci debljine od 2-3cm do 70cm u vapnenatkoj zoni debljine 5m. Utvrden je vrlo varijabilan stdrhj pirolizirane organske tvari (0.43%-20,74%, x=6,31% od 12 uzoraka) te varijabilan sadrhi gornjih toplinskih vrijednosti (92 kJ/kg-6338 kJ/kg, x=2143 kJ/kg od 7 uzoraka).

U Rebidima, 5,5 km juZno od Barbana u Istri, nalaze se gornjokredni slabo kerogeni vaqnenci s 0,19%-0.66% ukupne organske tvari (x=0.34%, N=9) i mjestimiCno s malo bitumena. Pirolizu organske tvari na 550~~110m in., kojom je procijenjen sadriaj ukupne organske tvari, te pirolizu organske tvari na 3 5 0 ~m~in.~, k0ojo m je procjenjen sadrhj bitumena naCinio je B. $tipak, kem. tehn.

Prema i q d t u Garapicsa i Panka iz 1804. (E r c e g, 1992) ispravno je zakljukno da postojanje "smole" u dubini ne bi naplatilo muku oko kopanja rudak, ali je neispravno zabiljefen naziv nalaziSta "Sebische" umjesto "Rebische" stoga je ono palo u zaborav, pa nije naznakno na "Osnovnoj geoloSkoj karti" list "Labin" (S i k i C et al, 1969). Ipak ostao je oCuvan potkop (sl. 22) pretpostavlja se od prije 150 do 200 godina, dimenzija 5,5m x 1,6m x 1,85-1,05m. U njemu se nalaze turonslu plohsti vapnenci sa sitnim kerogeniziranim foraminiferama. U vapnencima ima kerogenih pjega veliCine 0.05-lmm u mikritnoj osnovi fosilifernih mikrita i biomikrita. Tragove bitumena sadrie uzorci uz rasjede. Organska-kerogena tvar nalikuje ugljenu, a nalazi se preteZno kao prevlake po stijenkama pukotina. Godine 1927. pokuSali su Talijani obnoviti istrazivanja kopajuti raskop, ali bez uspjeha.

Nova- sazoanja iz rudarsko~geolol~hii sraiivanja bituminolnih kerogenih naladSta

Na temelju dosadaSnjih spoznaja o rudarsko-geoloSkim istrdivanjima bituminoznih stijena u Dinaridima Hrvatske autor predlaie da se u "Posebnim kriterijima za utvrdivanje i razvrstavanje rezervi pojedinih hrstih mineialnih sirovina" "Pravilnika o prikupljanju podataka, naCinu evidentiranja i utvrdivanja rezervi mineralnih sirovina te o izradi bilance tih rezervi" (N a r o d n e n o v i n e, 1992) odvoje bituminozne od uljnih tj. kerogenih stijena.

Bituminozna nalazsta u skladu s Pravilnikom moguCe je podijeliti u tri skupine s obzirom na razliEit stupanj infiltracije i impregnacije stijena ugljikovodicima, odnosno bitumenom. U prvu bi se skupinu uvrstila nalaziSta s 300 x l d t bituminozne stijenske mase, dru u skupinu sa 100-300 x l d t i treCu sa <I00 x 10 t bituminozne stijenske mase. Podjela u podskupine je moguda, ali tek nakon opseZnih rudarsko-geoloShh ispitivanja. Za istrazivanje bituminoznih stijena predlak se najdulji razmak izmedu rudarskih istraznih radova prema tablici 2.

BuduCi da nije definiran udio pojedinih kategorija u ukupnim rezervama, predlaZe se da rezerve A+B kategorije Cine 60%-75% ukupnih rezervi, od toga A kategorija 2/3 A+B r e z e ~a, C I kategorija 25%-40%.

Za raEunanje p o t e n c i j a 1 n i h rezervi (C2, Dl i D2 kategorije) treba prethodno izraEunati koeficijent produktivnosti detaljno istraiivanog podrucja (bilanciranog A+B+Cl kategorijama rezervi), kao i odnos bituminoznosti povrSina kojima se procjenjuju kategorije potencijalnih rezervi i (ukupne) bituminoznosti povdina koje su detaljno istraiivane kao korektivnom faktoru za-procjenu rezervi.

Prema sadaSnjem stupnju ktra~enosti, koji je uglavnom nizak, jer se uglavnom temelji na p- roc-j eni potencijalnih rezervi, v&ina prospektGanih, ili pak dijelom ispitanih nalaziSta bi spadala u trdu skupinu nalazi~ta.- U drugu skupinu - bi spadalo nal&i~te ViniSk-Biskupija, a u prvu skupinu pretpostavlja se Vrgorac-Paklina, ukoliko sesljedecim rudarsko-geoloSkim istra5vanjem umde v& rezerve.

Ovisno o kakvoCi sirovine, tj. poglavito sadrhju bitumena moguh je upotreba bituminoznih stijena. Za cestogradnju je povoljan viSi sadrbj bitumena >5%, tj. 6%-10% ili 72%-12,5%, dok sadrZaj bitumena za punilo praktiEki nema donju granicu. Sadrhj bitumena 1%-2% u stijeni predlaie se kao uvjetno bilanEnu kakvoCu, a >2% kao bilanEnu kakvodu.

Kerogene, odnosno uljne stijene svrstavaju se takoder u tri skupine, s neophodnom pripomenom. Ako se u njima nalazi I tip (sapropelni) i I1 tip (sapropelno-humusni) kerogena tada su to "uljni Skriljavci", a nalazi li se u njima I11 tip (humusni) kerogena to su "ugljeviti Skriljavci".

U kerogenim stijenama kerogen moie biti manje ili vise jednoliko koncentriran u cijeloj stijeni. To su homogeni uljni Skriljavci (u nas su rijetki). Kerogen se najWCe nalazi u laminiranim ili tankopl&stim naslagama u izmjeni sa sliCno takvim ali "jalovim" dijelovima s vrlo malo kerogena ili bez njega, ili se nalazi u slojevito-lehstim nakupinama. Prema velizini me& naSim kerogenim nalazgtima treba razlikovati prvu skupinu s ukupnim rezervama viSe od 3 x 10% kerogenih stijena, drugu skupinu sa 3 x 105t-3 x 106t i tretu skupinu sa <3 x 10%k erogenih stijena. Kerogena naladta PoStaka, pretpostavlja se, mogla bi npr. uvrstiti u prvu skupinu, Vrdova-Golo Brdo u drugu skupinu, a Brata-Brizi u treCu skupinu. Po dosadaSnjim spoznajama samo mali dio (1110) kerogenih stijena iz prouihvanih nalaziSta bi se mogao rabiti u energetske svrhe (npr. kerogena nalaziSta u Vrelu KoreniEkom). S obzirom na uglavnom nisku (d.) toplinsku vrijednost ispitivanih srednjih uzoraka, dikla naladta Mrsinj Grad u Vrelu KoreniEkom (x=1986 kJkg od 52 uzorka) utvrdeno je da ispitane stijene mogu biti samo izvor inicijalne energije za poktak gorenja (1650 Hkg). Zato se naSi niskoenergetski kerogeni "Skriljavci" mogu primjeniti samo kao punilo u asfaltnim mjdavinama.

U istra2ivanju kerogenih stijena predlaie se najveti razmak izmedu rudarskih istrainih radova prema tablici 3.

Ovi su razmaci znatno bliii razmacima, koji se primjenjuju u istraiivanju bituminoznih i uljnih stijena (N a r o d n e n o v i n e, 1992). Za istraiivanje lehtih kerogenih nalaziSta primjereniji su razmaci rudarskih istrainih radova koji vrijede za bituminozna nalaziSta. Isto to vrijedi i za mijdana bituminozno-kerogena nalaziSta (Gornja RoSca i Novska-Paklenica).

Pri geoloSkom istraiivanju i kartiranju nalaziSta s izdancima stijena obogatenih s organskom tvari (bitumenom ilili kerogenom) najveCi geoloSki rizici postoje pri procjeni potencijalnih rezervi, zbog nedostatka rudarsko-geoloSkih radova. Ti se rizici smanjuju ulaganjem u istraiivanje. Uz geoloSke znatajni su i ekonomski rizici. Tako npr. cijena industrijskog bitumena povehva se ili smanjuje s promjenama cijena nafte na triiStu. Zato prije odluke o eksploataciji treba naEiniti ekonomsku analizu koStanja dobivanja 1 t prirodnog bitumena iz asfalta i 1 t bitumena iz nafte, ili pak odrediti cijenu koStanja 1 t prirodnog punila s organskom tvari, te 1 t industrijskog punila istog sastava.

Nadalje, treba dakako ocjeniti i eksploatacijske rizike. PNO valja spoznati da se dosadaSnjim kriterijima (N a r o d n e n o v i n e, 1992) moie sa sigurnoSCu raCunati na rezerve koje ielimo odrediti i drugo da li s predloknim novim kriterijima o minimalnom razmaku izmedu rudarskih istrakih radova (tablice 2 i 3) je to ekonomski opravdano, itd.

Na temelju rudarsko-geoloSkih i geofizitkih podataka o debljini bituminoznih IeiiSta i nalaziSta, te debljine izdanaka, pribliZno Sam procjenio zalihe naSih znatajnih leZiSta i nalaziSta. VeCina nalaziSta sadr2i 5-10 000 t prirodnog asfalta, a samo nekoliko nalaziSta ima zalihe 80 000 t (tablica 4).

Medu naSa najznatajnija IeZiSta spadaju Paklina kod Vrgorc., ViniSQ-Biskupija, Primorski Dolac-Balovi, Donji Dolac-G. RoSca i dr., gdje je svuda prekinuta eksploatacija. Neka nalazsta bi trebalo detaljnije rudarsko-geoloSki istraiiti, kao npr. u mosorskoj bituminoznoj zoni (Donji Dolac - Okruglice i MiSetin Dolac), i u biokovskoj bituminoznoj zoni (Kozica, VranjeSi i GrljuSiCi).

Od leZiSta "uljnih Skriljavaca", odnosno kerogenih sedimenata, najinteresantnija se nalaze u Rudi kod Sinja i Vrelu KoreniEkom (Zubovih i MilanoviCa Draga). U Rudi je prekinuta nekadaSnja podzemna eksploatacija, dok su u Vrelu KoreniEkom bila zapokta, pa prekinuta. Od ostalih nalaziSta u kojima su zapokla istrazivanja, pa prelunuta, interesantna su na BraEu (Brizi) i Dinari (Vrdovo), jer sadr2e i poaene sadrhje organske tvari, tj. kerogena, a s time i poviSene toplinske vrijednosti sirovine. Za v&inu nalaziSta moie se zakljuBti da ih je za sada neracionalno istraiivati, jer sadrie uglavnom niske sadrhje organske tvari. U toj je grupi i naSe najvete kerogeno nalaziSte "PoStak". Procjenjuje se da geoloSke zalihe navedenih veCih nalaziSta dostiiu od 300 000 do 2 400 000 t, a manja nalaziSta (na BraEu) oko 60 000 t (tablica 5).

Pretvaranje resursa u rezerve

Uz pronalaienje novih nalaziSta bituminoznih i kerogenih stijena znatajno je i pretvaranje resursa u nekim nalaziStima u rezerve. Do otkrita novih nalazgta dug je put. Povezan je uglavnom s rudarsko-geolodkim te organsko-kemijskim i tehnoloSkim ispitivanjima sirovine.

Transformacija resursa u rezerve moguh je kod vrlo perspektivnih nalaziSta gdje su odredene uvjetno-bilantne zalihe, koje na taj nazin postaju bilanEne, a nalaziSta postaju IeiiSta, ili se pak nekada napuStena nalaziSta s niZe kvalitetnom sirovinom reaktiviraju. Transformacija je dinamibn proces (S i n g h, 1984), a najCeSCe je u svezi s novim tehnologijama primjene sirovine s niZim sadrhjem korisne komponente. Tako je to npr. za bituminozne i kerogene stijene i njihovu primjenu u punilima za cestogradevne sustave, a posebno za kerogene stijene ("uljne SMjavce") za njihovu primjenu za specijalna uljnamaziva(Encic1opedia italiana,1949),ili za njihovo sagorijevanje u fluidiziranom sloju poput nisko kalorihih ugljena i ugljevitih sedimenata, ili pak za njihovo sagorijevanje u Sterlingovu motoru @rema usmenom prioenju prof. A b r a m o v i C a). Nadalje, jaloviSta ugljena i uljnih Skriljavaca postaju zanimljiva u fertilizacijske svrhe, ali ujedno i za rekultiviranje njihovih povrgina u gospodarstvene svrhe i u druge namjene. Na naftnim i/ili plinskim poljima postojeCim buSotinama mogude je provesti otplinjavanje nabuSenih slojeva ugljena odnosno kerogenih sedimenata. Plin metan mogao bi se dobivati i iz rudnika, gdje se nalaze na pr. ugljeni, ugljeviti sedimenti i sl.

R a s p r a v a i zakljuEci

Poznato je da su bituminozne stijene (prirodni asfati), i kerogene stijene ("uljni Skriljavci") obogaCene s organskom tvari. U Hrvatskoj su to uglavnom karbonatne stijene: vapnenci i dolomiti, a manje pjdknjaci, siltiti, Sejlovi, Certovi i dr. U njima sadrhj topivog bitumena i/ili netopivog kerogena, iz kojeg se moEe dobiti ulje, mok znatno varirati. To se odrahva na promjeni kakvote sirovine i veliCini nalaziSta. Ovisno o sadriaju bitumena i/ili kerogena u ukupnoj organskoj tvari ili u stijeni mogude je ispitivanu stijenu uvrstiti u bituminoznu ("bitumenac"), ako sadrZi >50% bitumena u ukupnoj organskoj tvari ili kerogenu ("kerogenac"), ako pak sadrZi >50% kerogena u ukupnoj organskoj tvari. Dalju je podjelu mogu& naCiniti prema slici 1, s 1 ili 2 hibridne stijene, pa se moie razlikovati praktiCna "trodjelna" podjela. Moguta je i Cetverodjelna podjela kao u podjeli hibridnih karbonatnih stijena (5 e b e C i C, 1983). U skladu s time mogu se izdvojiti "kerogeni bitumenac" ili "bituminozni kerogenacW.Uskladu sa S c h m i t z o v o m podjelom (1986) mogude je jednotipne organolite podjeliti na "Cisti bitumenw- "bitumenac" - "bituminozna stijena" te Wsti kerogen" - "kerogenac" - "kerogena stijena".

Rudarsko-geoloSkim istrafivanjima bituminoznih i kerogenih leZiSta u Hrvatskoj doSlo je do spoznaje da je potrebno posebnim kriterijima vrednovati bituminozna, a posebno kerogena nalaziSta. Stoga su i razmaci izmedu istrahih radova (tablice 2 i 3) prilagdeni kategorijama A, B i Cl rezervi. Bituminozua nalaziSta podjeljena su na tri skupine s remvarna >Ya x ldt, 1WYa x l$t, i <lCKkldt, a kerogena nalaziSta s rezervama >3 x 10 t; 3 x 16 - 3 x 10% i ~ 3 x 1 Z6a~ is traZivanje bituminozno-kerogenih i letastih kerogenih nalaziSta primjereniji su razmaci izmedu buSaCih i rudarskih istrainih radova koji vrijede za bituminozna lefiSta. Prije odluke o istraiivanju i eksploataciji nekog starog nalaziSta treba dobro ocijeniti ekonomske i eksploatacijske rizike.

Kako se ne raspolaZe s podacima o eksploataciji prirodnih bitumena u Hrvatskoj u srednjem vijeku, vet samo u ranom novom vijeku, to sva razmiSljanja o moguCem dobivanju pakline u srednjem vijeku u nas poprimaju znaknje bolje ili loSije hipoteze. Pretpostavljam da je bitumen dovaian iz nalaziSta bliskih moru kao Sto je nalaziSte u ViniSCu, zatim na otoku BraCu (PuCiSCe i h i p ) te u blizini rijeke Neretve (Paklina). Da je ViniSde mogla biti luka za izradu i/ili popravak brodova, osim njegove povoljne lokacije izmedu Sibenika i Splita, odnosno blizine Trogira, svjedok ostaci stupova u moru u viniSkom zaljevu.

Od davnina je zabiljekna primjena prirodnog bitumena, odnosno pakline, u hidroizolaciji brodova i hmaca, u podmazivanju, u graditeljstvu, u obrambenoj svrsi pri opsjedanju utvrda gradova, u pomorskim bitkama "grCkom vatrom? dr. Paklina se mogla koristiti iz vlastitih nalaziSta, uvoziti, ili se pak umjesto nje mogao rabiti katran dobiven destilacijom drva.

Povijesni je tijek rudarenja bituminoznih odnosno asfaltnih nalaziSta u Hrvatskoj dulji od 400 godina. Prema M a t t h i o 1 i j u (1565) moiemo konstatirati da se jedno od najstarijih nalaziSta u Dalmaciji nalazi u blizini US& Neretve. Potrebno je istaknuti da se druga vrlo stara nalaziSta nalaze u ViniSCu nedaleko mora (sada "Opatija"), i u brdu ("Biskupija"), zatim na BraCu u Skripu i dr. U Panonskoj Hrvatskoj najstarije nalaziSte bitumena, odnosno oksidirane nafte, zabiljeZeno je u Peklenici u Medimurju. Sredinom XIX. stoljeh zapotinju intenzivna istraZivanja asfalta u mosorskom podruCju (Krivi Dolac), a n&to prije obnavlja se eksploatacija asfalta u ViniSCu ("Opatija"), kada je tu utemeljena prva "tvornica" za preradu asfalta. Vrhunac proizvodnje asfalta dosegnut je koncem XIX. stoljeh.

Eksploatacija kerogenih nalaziSta, odnosno "bituminoznih ("uljnih") Skriljavaca" ranije zvanih "kameni (ili "fosilni") ugljen" zapokla je prije 200 godina u SmirCi na BraCu. Saznanje o tome moiemo zahvaliti naSem istraZivaCu J. BiliCu (Billio), koji je uhtvovao i u istraZivanju prominskih i skradinskih ugljena. BraEki "kameni ug1jen"je odvoien u Rijeku za potrebe rijeCke S&rane. "Uljni Skriljavci" otkriveni su ubrzo i u Istri (Trlji), Sinjskom polju, Slivnu (Kremena), a sredinom XIX. stoljeda ponovno na BraEu (NereiiSk, Splitska i Mirca). Najznabjnije razdoblje za uljne Skriljavce Hrvatske povezuje se na poktak njihove prerade u Baljevcu i Sinju poktkom i sredinom XX. stoljh.

0 "uljnim Skriljavcima", ili kerogenim sedimentima osobito se raspravlja u vrijeme energetskih kriza ili povehnih energetskih potreba, a to je vrijeme svjetskih ratova, gospodarstvenih i politiEkih blokada, zatim nakon vedih skokova cijena nafte i plina na svjetskom trZiStu, a i pri nedostatku novih rezervi osnovnih energetskih sirovina. Razlog Sto se u svijetu malo eksploatiraju u tome je Sto ulje iz "Skriljavaca"j03 ne moZe konkurirati jeftinoj nafti. Prema tome kerogeni sedimenti, kao alternativne energetske sirovine, energetski su resursi budutnosti.

Kako rudarstvo zahtijeva financijska ulaganja u istraZivanje, a k tome i znatno veCa ulaganja u eksploataciju sirovina, mnoga su planirana ili zapokta istrazivanja prekinuta jer niti u proSlosti, a i niti u sadaSnjosti nije bilo odgovarajuEih investitora; bolje r&no velikih glavnihra, kao Sto je to bio u XIX. stoljetu barun Rotschild, koji je nastavio vet prekinute rudarske aktivnosti kao npr. u ViniSCu i Vrgorcu, ili ih je Sam zapoko, Sto je sluhj s kopanjem ugljena u SiveriCu i dr. Nadalje, problem je bio Sto domati poduzetnici, da su i imali kapitala, nisu imali znanja za izvodenje velikih radon. NaMost, situacija se nije bitno promijenila ni dams u XX. stoljeh. Kao izuzetak u tome moZe se istaknuti mjernik A. DeSkoviC iz OmiSa (Ad r i a t i c u s, 1905) koji se uz francusko-talijanski kapital angaZirao na podizanju hidroelektrane "Gubavica", kasnije nazvane "Kraljevac", na slapu rijeke Cetine u Zadvorju 1912., pouten iskustvom gradnje naSe prve hidroelektrane "Krka" na rijeci Krki (Supuk i Meichsner 1895 iz G ar i b o v i t i M o s e r, 1995) energijom poditi industriju asfalta i ugljena u Dalmaciji potetkom XX. stoljeh.

U Hrvatskoj se danas ne eksploatira ni jedno bituminozno ili kerogeno leZiSte. Uz manje prekide za svjetskih ratova, ili istrafivanja, najdulje se rudarilo na podruEju Vrgorca u Paklini i u ViniSCu na nalaziStu Opatija i Biskupija. Sva su druga nalaziSta manjh dimenzija i kraQ su eksploatirana i istrativana. Istrafivanje i rudarenje je obnavljano u viSe navrata, kako su se mijenjali drugtveni sustavi i potrebe. Od poznatih leZiSta vrgoraeka je Paklina eksploatirana sve do 1986. Potrebno je istaknuti da su rudarska istraZivanja pretetno bila prospekcijska, dok je samo nekoliko leZiSta detaljnije rudarski istraZivano, a to su asfalti Pakline, Skripa, ViniSCa i Donjeg Dolca, te "uljni Skriljavci" Rude kod Sinja, Vrela Koreniekog i Baljevca. Izradivana su geoloSka dljenja o kronostratigrafskoj pripadnosti, polohju i naCinu javljanja le%Sta, procjenama rezervi, o kakvoti sirovine, a izuzetno o fiziCkim svojstvima stijena, koje sadr2e organske tvari. Ponegdje se raspravljalo o genezi organske tvari, a u novije vrijeme i o naftno-geoloSkim znahjkama stijena u kojoj je organska War akumulirana primarno ili sekundarno.

Novijim rudmko-geo1oWm istra2hnjem obuhvateno je samo nekoliko leZiSta. To su bituminozna leZiSta iz trogirskog podruija (ViniSCe-Biskupija i Ninkvita Lokva u RadoSitima), jedno bituminozno-kerogeno le2iSte iz mosorskog podrutja (Gornja RoSca u Donjem Dolcu) i jedno iz slavonskog podruEja (Paklenica kod Novske).

Preliminarnim kemijskim i fizitko-kemijskim ispitivanjima bitumena i stijenske mase dobiven je tek uvid u mogutnost primjene i to za punilo za asfaltne mjeSavine, kao dodatak za asfaltni beton, za hidroizolacijsh materijal i sl., medutim prirodni asfalt, valja joS detaljno tehnoloSki ispitati da bi se mogao optimalno iskoristiti.

S novijim rudarsko-geoldkim istraiivanjirna kerogenih stijena, tj. "uljnih ili "bituminoznih Skriljavaca" tek se zapoklo prije desetak godina kod Vrela KoreniEkog na podruCju LiEke PleSivice i kod Dimih na PoStaku, tako da je u ovom trenutku nemoguCe procjeniti potencijalnost ove sirovine u H~atskoj za njenu mogutu uporabu. Naime, prva ispitivanja pokazala su skromne rezultate u svezi kakvok sirovine, pa se stoga mokmo samo prisjetiti kako je uz staru tehnologiju "majlera", vjerojatno odabrane sirovine, dobivena odredena kolitina sirovog ulja u Rudi kod Sinja. Povezano s time znana je i ljekovitost preparata na osnovi estrahiranog ulja iz baljevatkog,odnosno pldivitkog ihtiolskog "Skriljavca".

Na temelju dosadaSnjih istraiivanja bituminoznih i kerogenih stijena Dinarida Hrvatske te analititkih podataka o njihovoj kakvoti mo2e se zakljutiti da je u Dinaridima Hrvatske zabiljekno 173 le2iSta i nalaziSta. Od toga 42 pripadaju bituminoznim, 20 bituminozno-kerogenim, a 111 kerogenim stijenama. Po kakvoti sirovine izvrSena je. selekcija medu navedenim lokalitetima pa je izdvojeno 30-tak letiSta, dok je vetina lokaliteta svrstano u nalaziSta. Od 30 letiSta 15 je bituminoznih, 13 je kerogenih i 2 su bituminozno-kerogena. Pretpostavlja se da bi tek polovina od navedenih 30 leZiSta mogla biti zanimljiva za buduh rudarsko-geoloska istradivanja. Veliki odnos (1:6) izmedu broja le2iSta i nalazista kako bituminoznih, tako i kerogenih stijena odraz je vrlo promjenjive kakvote ispitivanih sirovina. Bituminozna nalaziSta u nas odlikuju se s promjenjivom koncentracijom bitumena te s manjim dimenzijama bituminoznih tijela. Zato eksploataciju bituminoznih nalaziSta treba organizirati tako da se njome zahvati vise nalaziSta na nekom podruEju. TraZeni sadrhj bitumena postiti Ce se mijdanjem sirovina s razlititim sadrZajem bitumena, a po potrebi i dodavanjem industrijskog bitumena. Nadalje, potrebno je imati na umu da je ekonomski opravdana ona eksploatacija koja nije skupa, odnosno optereha dugim transportom sirovine do mjesta primjene. To vrijedi i za niskoenergetske "uljne Skriljavce" koji bi se mogli uporabiti u ciglarskoj industriji i industriji cementa, kao energetski i sirovinski dodatak.

Zahvala

Odabrane dijelove talijanskih tekstova iz arhivskih dokumenata preveli su mi gda L. AntonoviC, prof. iz INA, Razvoj i . istrazivanja i g. R. Sank prof. iz Talijanskog instituta za kultura u Zagrebu na cemu im srdazno zahvaljujem

Prbnjem: 8. III. 1995.

PrihvaCeno: 20. V.1995.

Sidebar

The History of the Exploration and Exploitation of Bituminous and Kerogenous Deposits in Croatia

B Sebecic

Introduction

The history of exploration and exploitation of bituminous deposits, or natural asphalts and kerogenous deposits, respectively "bituminous" or "oil shales", sometimes confused with "stone" or "fossil coal", is connected in Croatia, according to old documents, to the early modem period. It is then that the first data are registered about the extraction of "piss asphaltus" "near Hvar, not far from from the Neretva" in Dalmatia (M a t t h i o 1 i, 1565), "earth wax" in Panonia, and "pegola" (It.: pitch) in ViniS6e 1628, 1668, (P r i u l i, 1668; B a r b a r o, 1670).

In 18th and 19th centry Croatia new occurrences and deposits of pitch were found, and mines started (Paklina (the word itself means pitch), Skrip and other places) and in the middle of the 19th century work started here too on the processing of pitch (ViniSCe, Skrip and other places). As well as this, part of the asphalt was exported to and processed in Venice. Asphalt production reached a peak in the second part of the 19th century and the beginning of the 20th century.

There can be various hypotheses about whether asphalt was extracted in Croatia in the medieval period, but there was certainly trade in asphalt, or pitch, as proved by documents from the 15th century. One such is the testament of the Zadar priest Zubina dated"1437 (S u r m i n, 1898) on the back of wich there was written that S. Ratit, owned him 39 bolanE(coins)for bitumen ("pakal" in archaic Croatian). Another is document from 1381, of the Zadar notary Petrus d e S e r c a n e, who interrogated the captain of an Italian vessel, Simon dec. Baghini de Bertanor who had attempted to hide 12 barrels of "bituminous pitch" on board of his ship.

The exploration and mining of kerogenous rocks (oil shales), or their deposits, are certainly connectyed with the modern age, especially the end of the 18th century (1782), as far as the BraE deposits at Smirk near Mirca are concerned, as well as some small occurrences on the mainland, and the end of the 19th century, when the biggest Croatian deposit was discovered at Ruda near Sinj, as well as the PljeSivica oil shales at Vrelo Korenitko, Baljevac, Zavalje and other places.

While the use of natural bitumens, and artificial bitumens (tars), was very important in the past for caulking wooden boats and for military purposes, the use of "oil shales" was in the past mostly important in health care, veterinary science and such like, finding its most important applications in the 19th and 20th centuries as an alternative energy source.

The aim of this research has been to provide an acquaintance with the history of a branch of mining which was in the past a significant part of the Croatian economy, especially in Dalmatia and Lika. A greater insight was desired into mining entrepreneurship, as was the collection of knowledge from renewed mining and geological exploration into the bituminous and kerogenous deposits of Croatia.

Natural bitumen and kerogen in the rocks

According to the recommendations of a study group of the World Petroleum Congress (M a r t i n e z et al., 1987) "natural bitumen is a component of petroleum that exists in a semi-hard state in natural deposits." This is a brown to black sticky, elastic matter, composed mainly of hydrocarbons (66%-89%), hydrogen (7-12%), sulphur (1-lo%), nitrogen ( ~ 1 % a)n d oxygen 1- 2%). Heteroelements usually account for <lo%. It is otften contaminated with minerals, and if it infiltrates or impregnates rock, this becomes a bituminous rock.

A well-known synonym for bitumen (Lat.) is asphalt (Grk.); however, through later use the expression took on in Europe a homonymic significance, for it was used for rock infiltrated and/or impregnated by natural bitumen. In Croatian, some of the older expressions for bitumen are pakal (V r a n E i 6, 1595) or pekl, which S k o k (1972) links with "hell". Paklenica, which are in Croatia in some places geographical names of deposits of natural bitumen or asphalt. The word bitumen is also sometimes translated asntar"(BeI Iosztenecz,1760).

Bituminous shales are mixtures of organic and inorganic substances from which oil can be obtained, whence the name oil shales. Oil shales are characterized largely by the a very thin stratiform position of the sediments. They are more or less enriched by organic matter, later called kerogen, whence the name kerogenic rock (S c h l a t t e r, 1968, according to Y e n et al., 1976). This term shows that through heating parafin wax or oil can be obtained from it. Kerogen is a fossilized organic substance insoluble in usual organic solvents while bitumen is soluble (D u r a n d, 1980). Kerogen rocks can be interesting for petroleum geology explorations if they are mature, for they are the mother rocks for hydrocarbons. If in the rock in the organic substance there kerogen and bitumen (Fig. 1) they are bituminous kerogens, or kerogenous bitumens, according to which there is more of (3 e b e E i C, 1983). The dominance of bitumen (90%) in the total organic matter of the rock links us to "pure" bitumen(ide)s.

It performed the first (S e b e E i 6, 1978) complex division of carbonate rocks according to structural and textural characteristics of carbonate rocks, including their mineral and chemical composition, and then according to bitumen division and the pores of the rock in which the bitumen is located.

It is necessary to stress that in barren rocks with a very low organic matter content, that is, with low percentage parts of bitumen and/or kerogen, there can be relations of bitumen and kerogen in the total organic matter, as there are In genuine bituminous, bituminous-kerogenous and kerogenous rocks, wich has no practical meaning in application, unless the relations in the acumulation and migration of the contents mentioned are being studied.

Apart from divisions based on the relat~ono f the b~tumena nd kerogen content in the total organic matter (Fig. l), it 1s possible to call, in accord with S c h m i t z' s division (1986) of a monotype organolite with asphalt, which he calls "raw asphalt," "asphaltiden, and his corrected series would run as follows: pure asphalt-asphtaltide-asphaltenous rock, which with the synonym bitumen in our considerations would go" pure bitumen-bitumenide- bitumenous rock. In a similar way it is possible to make the series pure kerogen-kerogenide-kerogenous rock.

The basis for this division comes down to the mineral content contained <lo%, 10%-50% and >50%. In complex divisions with bitumen and kerogen the term is determined according to the dominant type of organic matter.

Bitnminous deposits and occurrences

According to well-known published data, one of the most ancient deposits of pitchy asphalt (pissasphaltus) is found "near Hvar not far from (the) Neretva" (M a t t h i o I i, 1565), which can refer to the Paklina of Vrgorac or the Slivno of the Neretva (Fig. 2) F o r t i s (1774) assumes that the Vrgorac mine worked before the "arms of Venice conquered this region". This seems to be logical too, because only a large deposit could have a long history of exploitation. About the asphalt deposit of Paklina archival documents exist (B o 1 d u, 1782) from which it can be seen that Croatian mining entrepreneurship in the region of Vrgorac was well organized as early as 1753 (Fig. 3), which was also written about by N o v a k (1962), S o I d o (1978), P e r i E i C (1980) and others. According to KiSpatiC (1901), who quotes F r i e s e (1858) it was written that the "asphalt stone in Vrgorac was being worked 1.. 50 years ago (i. e. in 1708), and many cases were held because of I,

In Dalmatia in 1850 production amounted approximately to 1, 000 Viennese cents (or 56 tons) of asphalt and over 2,240 tons of asphalt rock, which were transported to Venice to be made into asphalt mastic (F r i e s e, 1852).

It was Bmon Rokhild who continued mining activity in Paklina in the middle of the 19th century; from him, the company was taken oven by L Konig and son from Vienna. Mining was carried out along three mining districts called Paulina, Maria and Alexand(e)ria, from the names of Konig's children. In 1906, Paufina Konig took over the mine, and later the same year, the Asphalt Gewerkrchafi 'XAdria" from Split, and in 1930, Ruda dd from Split. During the 1949-50 period exploration was renewed by Zagreb's Naftaplin, and in 1953 the mining company "PaWinaUw as formed, which was in 1961 integrated into the specialized building company "Izolacija"f rom Belgrade, a part of which it was for about 25 years.

Up till 1961 in Paklina mining went on underground, while afterwards exploitation went on open-cast mining. The approximate amounts of asphalt produced are shown in Table 1. It was established that after long interruptions brought about by world wars, the old pit works were partially filled up with natural bitumen, and the proportion of high quality raw material increased (Fig. 4). Leaking og bitumen from fissures and cave spaces is visible even today in open cast mining (Fig. 5). Bitumen also fills up cracks and other smaller hollows, crumbling fragments, and it is present more or less in all bituminous limestones and bituminous calcareous tectonic breccias.

In Paklina mining was done through a combination of shafts andlor inclines and galleries. Mining was done mainly at a depth of 50 m, where the deepest 4th working level (gallery) was located. The second incline was directed from the 2nd working level at 25 m towards a depth of 75-80 m (according to "Excerpts from the old mining plan M 1:1000, which was dra'wn up in June 12, 1945, in Split "which is located in the archives of the "Federal Geological Institute" in Belgrade) and thus allowed for the achievement of the greatest depth in the subterranean mining work in Vrgorac. The deepest vertical shaft is found in the Paulina mining districit, 55 m deep, while the depth of the air shaft at the Alexandria mine field is about 40 m.

According to 3 i n k o v e c (1957) in the region of the previous asphalt mine region "Aleksandar" (earlier called Aleksander or Aleksandrija) there are reserves of B category asphalt breccia of 45260 tons, and 30000 tons of C1 category, inside and between the air and the cross shaft. Sinkovec assumes that in the region of the one time "Aleksandar" mining district about 50000 tons of asphalt breccia was taken out. He concludes that in the region of the Paulina and Marija mine fields there are reserves of asphalt breccia, although the fields were not available for him to do research into. The proven reserves of bituminous, or asphalt stone have been established at 86300 tons, including 16400 tons of A, category, 25100, tons of B category and 44800 of C category, with a 10%-18% bitumen content but with an estimated 340000 tons of 7.2% bitumen, with the proviso that 60% of the reserves have 12% bitumen content (P a 1 r 1 j, 1975). The question of the evaluation of reserves is linked with difficulties about the direction of future exploration, for the results before the exploratory drills made are very modest.

At Vrgorac a plant for raw material processing existed, and consisted of a crusher, a mill and a plant for the preparation of mastic and insulated sheets. In the past, many bridges, terraces, insulated warehoues, reservoirs and other things in Europe were covered with Dalmatian asphalt. In 1886, several crystallization salt basins in Ston were covered with Vrgorac asphalt; St Mundo was still almost undamaged in the fifties of the 20th century. The greatest part of Sarajevo was also asphalted with this material (A no n., 1932)

In ViniIh, natural asphalt was being exploited in 1668 (Fig. 6) and in 1628 (B a r b a t o , 1670, S o l d o, 1978) and is assumed to have been earlier too (S e b e E i C,1984), for natural bitumen was mostly used in the middle ages and partially in the modem period for the bitumenization of wooden ships. Only unreliable hypotheses can be made about whether any of our most ancient deposits of asphalt were known in the period of the Croatian rulers, of Prince ~ o h q o(j9t h century) and -King Zvonimir (11th century when there was a powerful navy. According to an oral communication from my late colleague Hanich, ViniSCe might have been a harbour for ship repairs, for reviewing photograms of the sea in the ViniSCe bay he noticed the remains of pillars for tying up ships, and the deposits in ViniSCe are close toJhe sea. Since the occurrences of natural bitumen on Bra? and Ciovo (F o r t i s, 1774) are not significant, the deposits in ViniSCe might well have had an appropriate importance in the distant past, especially since artifical pitch (tar) is not mentioned in the statutes of Brat and Trogir, as it is in the middle ages and later mentioned in the statutes of the islands of KorEula and Hvar and elsewhere, where pitch was made from fir and pine, for there, in the past, no deposits of natural asphalt were recorded, and the needs for artifical bitumen for the ship-yards of Koreula, Hvar and Venice were quite considerable (P e d e r i n, 1990)

The owners of the ViniSCe deposits were the see of Trogir, according to which the deposit en the hill above ViniSCe was called Vinisce-Episcopal (Biskupija) (S e b e E i 6, 1984) and the Trogir Abbey of the Benedictines (ViniSCe-Opatija, S e b e E i 6,1984). As late as 1670, at the appeal of the Trogir see's "Council of Ten" it was forbidden for mining entrepreneurs to do anyth~ngo n the hill above ViniHCe, because they were usurping the lands of the Diocese. Similar attempts where made approximately 175 years later, after the renewal of mining activities in VinS& Abbey (Opatija) when the heritor of the Abbey, the Split Seminary sought protection from the Trogir Curt, whic banned the removal of asphalt from ViniSCe to Venice, while the entrepreneur Baron Rothschild did not buy plots of land where the deposits were found. Alongside the Vinik%-Opatija deposits, the German" engineer Hermann, Rothschild's factor, set up several mills (S l a d eS i I o v i 6,1939) for crushing asphalt limestone, and a vat or stove for heating and melting the bitumen, which was aftemds strained into barrels, or, from the black sluny, mastic cake was made, and was as a semi-hished product or only as a raw material, transported in sailing vessels from 1840 on, and, it can be assumed, until the end of the 19th century to Venice and elswhwere.

In ViniSCe, according to B a u E i C (1943) there was the first Croatian asphalt factory, which stopped operations on the eve of the First World War. ViniSCe asphalt, aparat from being exported together with that from Vrgorac and Skrip (M a r s c h a 1 1, 1856) to Venice, and elsewhere in Italy, Austria, Prussia and elsewhere (Tam b u r i n i, 1852) was used also in Dalmatia for the asphalting of storehouses, terraces, underground rooms and the salt pans in Ston. A contract has been preserved between E. Hartung, an entrepreneur from ViniSCe, and The Financial Office of Dubrovnik, made up on July 5,1874 for asphalting the salt pan St Frano/Francesco/ or St. Francis, whith the area 845 square "Mafters" and 4-5 cm thickness. In a later contract of May 25,1876 Hartung undertook to asphalt the crystallization pan "Mondo" of similar size i.e. 870 square "klafters" (3,130 m2), which was paid 5,220.91 florins (grand-total) after taking over asphalted pan (S 1 a d e-3 i I o v i C archives, Trogir).

After World War 11, it was estimated that at pskupija there were from 10,000 tons of asphalt reserves (S i I a, S i n k o v e c, 1955) to 25,000 tons (G e m b a E e v et al, 1956) and trough exploratory drillings it was calculated that there where proven reserves of 100,206 t (S e b e E i C and T r u t i n, 1985), including 97,461 t of B category reserves, and 2,745 t of C1 category. It was estimated that there were potential reserves (C2+D1) in the northern zone, as it is called, where there has never been any drilling, so that all proven and non-proven reserves are estimated at about 175,000 tons, with a 69% degree of exploration. It has been established that the biggest bituminous body has a very complex structure. This is in fact a massive (Fig. 7) to stratified in thick beds body that is 0.10m - 26.20m thick. The average free toluene-bitumen content of the largest bituminous body comes to 3.05% (79 analyses), and glowing loss to 550°C, by which the kerogen and bound bitumen content were evaluated, was 0.58% (76 analyses). The average weighted free bitumen content for the drilled region was 2.29% (130 analyses), and glowing loss was 0.65% (130 analyses). Altogether for ViniS6e Biskupija the average bitumen content for 181 analyses was 2.00%, and glowing loss to 550°C was 0.76%. Altogether from the 213 analyses so far made average bitumen content has come to 2.24%.

Bitumen is found in various genetic pores of senonian biogenic limestones mainly in biomicmd~tes and bio(pseudo)sparrud~tes Gg- Pp-Ww-Pp-Gg of limestone sequence, which are characterized by better qualit~esa s collectors as compared with underlying and overiymg biomicrite limestone. Apart from the exploratory drilling, in the course of which 34 exploratory drills were made between depths of 20 m and 66.8 m, with an average depth of 32.23 m, mining and geological research was carried out by mining trenchs, adit and deepening the old shafts. Of the old mining works two "minCj)ereU stand out, which are linked by a tunnel and one exploratory shaft. From this we can conclude that only a small amount of the reserves has been extracted from Biskupija.

The bituminous deposits of ViniiCe-Opatija (Fig. 8) have been deep mined, in three levels, with the deepest level at 15 m, where sea level was reached. Because of the proximity of the sea and residential housing it is not suggested that exploration in this region should be renewed. Bituminous limestones are biomicrites in type wackestone (w) and contain 2.04% bitumen (4 samples).

Of the other Trogir bitumen deposits apart from ViniSCe the most important are the bituminous Upper Cretaceous limestones of Balovi in Primorski Dolac and the bituminous Upper Cretaceous dolomites of NinEeviCa Lokva in RadoSiC. The first deposit was mentioned ln the past under the name of Suhi do1 (S c h u b e r t, 1909), and earlier still, in 1804, a Suhi Dolac, which is the old name for Primonki Dolac. This is a shallow, open pit on a hill slope (Fig. 9) known among people as Paklinka, while another, smaller deposit was later discovered in RadoSiC (S c h u b e r t, 1909), with there being a shallower surface mine in the meadow. All the others are smaller bituminous occurrences., including that on Ciovo, which Fort~dse scribed in great detail in his travelogue of 1774 (Fig. 10).

The first response to Fortis'sdescription of a "mine of pitcy asphalt" on the western cape of Ciovo was made by an unknown informant of Maria Theresa (S o I do, 1978), who wrote about this bituminous occurrence (in approximately 1776) that it was of excellent quality, but that only a few pounds could be collected, just two to three kilos (N o v a k, 1962). P e d e r i n (1991) presumes that this secret report was written by some person from the circle of W&eh Bol~sa, German born in London, who is responsible for the founding of the "Triester-Ustindische Handels kornpanie" 1776 in Trieste. The unknown report blamed Fortis for suggesting to the Venetian authorities, on the basis of inaccurate information, that they should go in for exploiting the deposits, which nevertheless they did not do. Then, the infopant writes that there was a bit more pitch at another place, near Skrip, on Brat, in a valley before Vrgorac (the occurrence of Kotezi) and not far from Sinj (Dipalavo vrilo) and south-west of Sinj.

In the Neretvan reglon at the foot of the Raba Mountain, that is in Slivno, Fortis mentions another mine of asphalt, with the proviso that he had not v~sitedit . The asphalt "mine" of St Ivan (as he called it, without evidence) In "PuEiSCe" In BraE was also no1 found by Fortis, although Dr Bajamonn' was supposed to have shown him a sample from the local~tyF. ortis stated that the fossils in this asphalt stone were different than those he had seen in other asphalt deposits in Dalmatia (F o r m a 1 e o n i, 1786).

In the northern part of the island of Brat, not far from the town of Skrip, lies an abandoned asphalt mine (Fig. l l ) , of bituminous dolomite, where there was mining between 1750 and 1874. 'I'he biggest part of the mine is made up of several large cavern halls which were partly filled with accumulations of bitumen (Fig. 12) while in the incline and in the lateral galleries there is in places just a little asphalt, in narrow layers or spatterings. Therefore it is understandable that mining was abandoned. Nor were positive results given by later renewed mining activities with two adits in the eastern part of the deposits or by shaUow exploratory drilling, and so mining was abandoned altogether in this reason. As for more ancient mining works, a few trenchs are recorded at the eastern deposit.

Bitumen was extracted from the .!kip asphalt In two round stoves mainly The stoves were destroyed and one was filled in. The western part of the deposit was richer in bitumen (2.63%-9.40%) than the eastern (0.09%-3.19%). One the basis of 26 bitumen analyses it was calculated in 1968 that the average bitumen content was 3.57%, and out of 50 analyses, among which there were analyses of samples that were richer in bitumen, i t was calculated that there was a 5.94% bitumen content in the Skrip asphlats (K a n a j e t et al., 1995). Skrip bituminous dolomites and traces of bitumen in the mdistic limestones, or "BraE marbles", belong, according to J e r i n i C el al., (1994) belogn to a part of the PuEiSh formation. The kerogenous stromatolitic limestones of Mirca and Briz~o n Brat belong to part of the Sumartin formation (GuSiCandJelask_a,1990).

As well as in the Ship mine field, bituminous dolomite was extracted considerably later in the BraE mine field in Pod Badanj. Bituminous l~mestonesa re found not far from PuEiSCe and in St Martin (Sumartin), in the Dalmacija mine field, partly at Splitska and Mirca. Kerogenous limestones, or "fossil coal" were extracted in the Wilheh mine field south of Mirca, Gwav and Herman, in north west Brat, and in Kolacxi, south west of NereZiSCe, and in field called Ausmja, south of Drawica, in the south west of BraE. There are other kerogenous limestones at Bole, Zetevo, Postira and Sutivan (J e 1 a s k a et al., 1983).

All mining concessions (T o m a S i C 1949) obtained under Austro-Hungary were in orperation in the Kingdom of Yugoslavia, which is an indication of the one-time interest in the exploitation and application of both bituminous and kerogenous rocks It is necessary to stress that the deposits mentioned were never subjected to detailed geological research, irrespect~veo t the level of their mining research, and so it difficult to evaluate thelr geological reserves.

At the beginning of the 19th century there was in Skrip a production of natural asphalt with 9-10% bitumen, which was exported together with the asphalts from Vrgorac and ViniSCe in wind powered merchant ships to Venice (M a r s c h a 1 I, 1856), where it was processed, either in the form of a semi-finished product or in that of a raw material. Product obtalned via the processing of natural asphalt from Dalmatia were shown at the Paris Exhibition of 1855, where there were 30 exhibitors from France, Austria, Bavaria, Spain, Portugal, Canada and Mexico.

Rights to extract asphalts from Brat and ViniSCe were gained in the second half of the 19th century by Heinrich (Enrico) Hartung, an entrepreneur from Trogir, of German origin. This IS given in the mining exploration license based on the Austnan mining law of 1854. This relates to the area covered by the Spl~ta nd Sinj port authorities. Hartung obtained it in 1873 (Fig. 13), and extended it in 1874. His 1879 certificare for free asphalt exploration in ViniSCe IS also preserved. A-ding to N i k o 1 i C (1900) the BraE deposits in St. Martin, Mirca, Skrip, Splitska and NerdiSCe were explored by the mining engineers of the Steinkohlen WerFchafr in 1840. Of all the deposits, most was promised by that in Sknp. Howwwer, in spite of a high production of 6.735 tons in four years, the Skrip mine got into difficulties and the bank let the mine out to private enterprises. In 1873 the mine was leased by the French LJAsphaheine, Societe Anonyme des Asphaltes et des Binunes de L'Adriatique, of Paris, from H. Hartung of Trogir. From documents of the Royal and Imperial notary Dr A. HocNcofler From Trieste dated January 15, 1874, it can be seen that Hartung promised to sell Asphalteine concessions for asphalt exploration. Since Hartung probably did not sign a contract, for he was given a reminder, it can be assumed that Asphalteine, seyng the complexity of the mining and geological situation in the Skrip mine gave up the right to priority exploration of the asphalt ore, and asked Hartung to keep 400 tons of asphalt already extracted in storage until a purchaser should be found (Fig. 14). As far as the asphalt deposits on Bra6 are concerned, S o h I e (1900) most of all describes &rip, the thickness of whose dolomite "sand", rich in asphalt, was estimated at about 20 m.

According to P e r i 6 i C (1980), G. Billio, probably Croatian Bilik originally, a geological explorer and mine entrepreneur discovered coal near Skradin, at Promina Mt. (SiveriC, Dubravice and VeluSif) and fossil coal on BraE (Smirk), where he also discovered asphalt. According to Diedo (S o I d o, 1978), Billio obtained together with D. Sami in 1782 the right to extract fossil coal throughout Dalmatia. Thus Billio began to mine fossil coal, that is kerogenous stromatolitic limestone on the terrain of Smirk (near Mirca, author) two kilometers south east of Sutivan, from which it was taken in sailing ships to the Rijeka sugar refinery. In a letter to his factor P. Bergalit, Billio said that at the beginning of 1791 there were about 12 waggons, or approximately 114 tons of "coal" stored in Sutivan.

In 1784 and 1785, M. &rnunoviC and N. ~imunovia~s, w ell as I. Srempit and M. Berd obtained from the magistrates a license to extract pitch from three "holes" in Martinica or Smirk. In 1781, A. LovriC from Sinj, together with t: Celio-Cega (S o 1 d o, 1978) obtained a License to mine black asphalt on the St Ciprijan Cape by Trogir, on payment of tithes, but it is not known whether extraction of asphalt was actually done here. In 1782 the Economic Society of Split was informed by letter about the occurrence of patches of tar on the mountain of Hum not far from the Benedictine monastery and church in KomiZa, on Vis by the Split physician Barbier; who said that the people called the place Paklenica, that tar (i.e. pitch) was dug up in this place and used for caulking the fishermen's boats (2 g a 1 j i 6, 1984). In 1786, the Moscatfi family gained the right to extract asphalt at Siveric; however, because of great losses, they gave up further extraction when the license expired (P e r i E i f, 1980).

After the downfall of the Venetian Republic, Istria and Dalmatia became parts of the Austrian Monarchy. The mining wealth in this region then known was registred In the Hofkammer (Court Chamber of Commerce). A tabular report about these explorations (Fig. 15) was drawn in in 1804 by P a n t z and G a r a p i c s; it was published, almost 190 years later, by E r c e g (1992). In total, they described 26 localities, of which 7 had earth pitch, that is: Barban in Istria, Suhi Dolac, Vrgorac, Slivno on the Neretva, Ciovo and Bra6 (Mirca and NerdiSCe). Earth pitch, or bitumen, lies in limestones and sometimes in lime marls. Pantz and Garapics determined that most of the localities had no value; the Slivno deposit was determined to have no useful natural product, while the Vrgorac deposit was assumed to have little expectation of being economically exploited, which was later contradicted. As for the deposits on Brat, they said that they had been explored during the the period of Venetian rule.

Among the Mosor bituminous deposits the first to be mentioned is the deposit in Dolac (H a u e r, 1850), or, in more detail, in Krivi Dolac (S c h I e h a n, 1851) where large mining works were carried out, the expenses of which for the period 1849-1851 were included in the current accounts (Fig. 16).

From the current account made up between Direction der adriatischen Asphalf Werke zu Venedig and Andrja Gross (1852) from Split it can be seen that the total earnings amounted to 15,748.52 fl., while expenses were 17,519.2 fl. In the expenses mention is made of those incurred by the Mining. Authority on Brat (1364.19 fl.) and in ViniSCe (530 fl.) and in the mining works in Vrgorac (300 fl.); hower, the major costs were incurred by the "Management of the Venetian Asphalt Processing Co.," during part of 1849, in 1850 and part of 1851 in the Mosor asphalt region, including Krivi Dolac (-4,967 fl.)

Afterwards R i t t e r et a1 (1855) wrote of pits north east of Split, probably in the Dolac region, which were called Alleanq Fedelta, Fiducia and Madonna delle Grazie. Later, K e r n e r (1916) described the asphalt deposits and occurrences in Donji Dolac: Okruglice, PutiSCa Stan, later calledStaje, Na Privaj, Gornja RoSca and Akrap, and later (1919) also Zupa, Kozica, Dretnica, Stikwo, RadoSif etc.

The Fedelta mining field in Krivi Dolac was assigned in 1847 to Cerineo and Gross; and later in 1850, very likely sold, to Rougieri. From 1930 on it was owned by Ruda dd Split. The neighbouring mine fields Paul and Virginia in Okruglice were from 1904 owned by the Hamburg Bergwerkgesellschafr, and from 1930 on were leased out to Engineer Grochowakki, the one time manager of the Vrgorac mine. In Gornja Rosca (Donji Dolac) and Akrap (Bisko), VidoviC and Sisgoreo of Split had, according to local oral information, an exploration concession. In Dolac Donji, i.e. Krivi Dolac, the mining exploration was financed bu the Vice- Regal (Banovina) Govennent in Zagreb too (Fig. 17).

In Gornja RoSca exploratory works were undertaken by trenching, and a little exploitation by deep mining. Through test drills it was established that the bitumen lay in the Upper Cretaceous and in the Eocene limestones and in tectonic breccias. Further, it was established that there was a deep link between nearby surface occurrences. The thickness of the bituminous bodies was on average 17.7 m. The bitumen content was on the whole grteater in the outcrops than in the drilled sedimentary layers, the higher quality raw material was only 1.5-6 m thick, and only exceptionally 16 m. For all sediments drilled the average bitumen content amounted to 0.76% (from 70 analyses): while it was for one drilling higher, that is, 1.62% for 27 analyses (S e b e E i 6, 1981). The average estimated insoluble organic matter content was 1.88% for 70 analyses from 6 dritlings (S e b e E i 6, 1977). According to the relation of free bitumen in the total organic matter in Upper Cretaceous limestones weakly kerogenousbituminous limestones are more common, while in palaeogenic limestones there are weakly bituminous-kerogenous limestones and weakly kerogenous limestones. It has been calculat~dt hat only 10% of the reserves contain good quality raw material (S e b e E i 6, 1977).

In the context of a review of Yugoslav, or Dalmatian natural asphalts, A b r a h a m (1960) distinguished the Vrgorac, Bra? and Morovice asphalts wilh old analytical data, while he erroneously put into Montenegran (it was perhaps suggested that he should do so) the deposits of asphalt in Dubrovnik, ViniSCe, Ciovo, and Suhi Do1 ac (North Trogir) asphalts, as well as asphalts betqween DrniS and Knin. Thus for example he writes that the Morovice weakly dolomitized limestones from the region of Sibenik contained 10-15% asphalt, while the VinidCe crystalline limestones have 9.2%, and the Dubrovnik (probably Gnjili Rat) limestones had 13.9% asphalt. The term for the asphalt locality MoroviC or Morovice probably derived from the name of the village Mokro on the border between the Sibenik and Trogir disticts (S t o S i C, 1941), and comes within the Danilo-Biranj parish.

That the asphalt deposit in Gnjili Rat on the PeljeSac peninsula was explored, if not exploited, in the 19th century is documented by the bitumen analysis of "probably" 25% (T r i n k e r, 1868). According to chemical analyses (J o h n and E i c h l e i t e r, 1901) the asphalt limestones of "Poljica" (D. Dolac) contained 32.94% bitumen, those of Vrgorac 31.04%. Later, a bitumen content for the Vrgorac asphalt of 16.32 was arrived at (E i c h I e i t e rand H a c k, 1920).

In Kozica Upper Cretaceous bituminous dolomites were explored before the First World War. There were two inclines of 25 m in length them. The bitumcn content varies between 0.90% and 11.20% (;;=3.87%, N=20), and the thickness of the bituminous zone was 1.5-3 m.

Sc h u b e r t (1909) says that the most important asphalt deposits in Croatia are in Vrgorac, which was well known in the 18th century, and after that, Kozica, Dolac, RadoSiC and Suhi Dol, Prapatnica and others, and on BraE there were Mirca, PiBSCa, St. Martin and Skrip. These are all Upper Cretapous deposits and occurrences. Of Jurassic deposits he mentions Stikovo, Kijevo and others, and those in Peljdac and Ciovo from the Eocene period.

At the end, there is still the unsolved problem of the origin of the spherical, secondary clusters of pitch (bitumen) washed up on the Pakleni Islands. For the moment it is ungroundedly common to link the occurrences of pitch with the name of the Pakleni Islands (Ag a I j i C,1994), for Croatian fishermen know nothing of mining for pitch on the Pakleni Islands. It is a fact that the Fiihermen used this spherical, apple-sized flotsam, sometimes even biger, and that they were found scattered over the bay beaches, much more over the northern than the southern sides of the islands. According to an oral communication from N. Gum& shipbuilding engineer from Hvar, the "ball-shaped" flotsam was brought by the currents, with the maestral wind from the north-west (Ciovo and/or Vinigk-Opatija) or from the south or south west (the Neretva valley, or clmer, from the eastern part of Hvar). Apart from this the possibility should not'be excluded that there some submarine occurrence of bitumen or oil that should be investieated.

East of Novska, especially between the ~aklenicas tream (Fig. 18) and VoCarac, several deposits of bituminous weakly bonded sandstones have been registered (S e b e E i C and B u 1 i 6,1983). They are about mm to m thick (maximum drilled 1.35 m). On the basis of geological cross sections trenching, cutting and prospectingexploring drilling it has been concluded that the bituminous sediments are limited in volume, because they alternate with barren sediments. In drillings, thus, the ratio of barren rock to ore varies from 4:l to 15:l. The bitumen content in the neogenic sediments of Banatica beak of Paklenica varies from 0.10 to 10.12% (x=3.76%, N=37). The geological reserves between the three drillings are estimated at 50,000 tons, and it is predicted that they might even be greater (OreSki and DurdanoviC, 1983). Because of the thinness of the layers and the steepness of the bituminous sediments, and their unfavourable relation to the barren sediments, not to mention the destruction of forest that would be required, it is not recommended that there should be further research in this region.

According to A n o n (1920), north east of BaEindol (Fig. 18) towards Cernik a fairly light oil pitch was found in several mine shafts. This encouraged a group of business people, Count Erdody, Baron Gwchreiber and traders from Sisak to build, in 1858, a factory of mineral oils, to obtain train-oil and lubricants for trains and coaches.

In Paklenica, MikleuSka, where a train oil factory was also built in 1860, and at Voloder on the slops of the Moslavacka hills, pitch was found in tertiary sediments. In a larger deposit in Paklenica several Viennese cents a day of pitch and oil mixed with water were extracted from a shaft 45-60 rn in depth. Later, 1905 the Vesta Co., showed by drilling the presence of pitch at a depth of 70 m, and earth gas at even greater depths. At Voloder, 4 km west of MikleuSka, the presence of bituminous rocks 4-6 m thick was demonstrated in a drilled sedimentary layer at a depth of four metres, from which a dark green oil oozed.

At Veliki Poganac (Fig. 18), drilling revealed nest-like gatherings of earth wax in shale, which would melt at 70°C. An occurrence of oil was discovered in this region after the earthquake of 1882; however, the exploratory drillings performed subsequenly did not give positive results.

Z a p h a r o v i c h (1859) wrote in his Mineral Lexicon that there was pitch in Peklenica (Fig. 18) in Medimuje, in tertiary sand on the bank of a brook, and in a shaft 3.9 m deep. This was repeated by R a u k a r (1932), who said that in 1836 a dark brown earth oil was obtained for train oil.

Kerogenous deposits and murences

Oil, or kerogenous sediments are found in various localities in Croatia in Dalmatia, Lika and Istria, and elsewhere (Fig. 18). Once upon a time crude oil was obtained from them, in Ruda, near Sinj, and Baljevac, near BihaC; it can be assumed that it was too in BruSani near GospiC. The oil was used for various purposes: medical, for power, and so on. According to knowledge to date, it can be concluded that the most high quality raw material was exploied at Ruda near Sinj and at Vrelo KoreniEko and Baljevac. By research into the majority of the occurrences and deposits it has been stated that the quality of the raw material in most localities can be used for low-energy requirements.

Subsequent exploration of the kerogenous deposits showed that a small part of the material was of good quality, because barren and kerogenous parts alternated in them, which considerably reduced the proven reserves of the deposits. Current exploration has not shown that there are any thicker-layered and stronger kerogenous sediments.

Of the Croatian deposits of oil shales the most important is found in Sinj - Ruda (Fig. 19), because it is rich in oil (30- 40%), and its reserves are estimated at several milion tons (L u k o v i C, 1936). The other deposit is Baljevac, with thin layers of up to 0.5 m, which were exploited for a short time, between 1901-1905. chemical and pharmaceutical company "G. Helf" from Troppan (Mining captaincy Zagreb, 1893-1901), From them, "ichthyol" was produced. As for oil shale occurrences in Croatia, E r c e g o v a c (1990). concluded that they had been only slightly explored, because there were no data about organic-petrographic and geochemical characteris9cs. This refers above all to the occurrences of Trlji and Saini in Istria, to PoStak in Lika, and to Svilaja and Ruda in Dalmatia. He considered that the occurrences of Pdtak and Ruda should be studied in detail, because the kerogen in them is of the sapropelic type.

It is assumed that oil shales were begun to be explored in Lika in the 19th century, for they were being pocessed in Baljevac 1901-1905. According to a translation of an anonymous German author we can conclude that the exploitation was divided into 5 concesions: Baljevac, owned by J. Pam (R e i t f e r, 1926) Zavalje Vrelo, Lapac and Korenica, with a total area of 51400000 m z' Resewes of 20000000 tons are quoted for Lika.

In Baljevac, exploitation of the Lower Cretaceous oil shales which was prior to the World War I1 performed by the Lika Mining Association and the "GyrodaP: Zagreb. There were four minor works (Fig. 20) at which mining was done by strip-mining, and by a combination of incl~nes and lateral galleries of some metres in length. The subsequent extraction of ichthyol was done in 8 retorts at a temperature of 520°C for 3 hours from pieces of crushed 011 shale the size of walnuts. Daily production of oil from the Baljevac deposits were 1.60 t - 1.92 t, or maximum of 700 t a year.

From the Zavalje, or Suhi Do1 deposit, which was exploited by a combination of cuttings, adits and galleries, about 0.2 t to 0.8 ton a day was obtained, or about 180 tons of oil a year (19471, and from the MedudraZje or Bijela Greda deposits 0.4 t to 0.5 t daily. There are no figures for production of the Korenica deposits, where exploratory works were done with two tunnels 12 m and 6 m in length.

Shales were processed in the oil factory in Baljevac, which after World War I1 belonged to Bosnia-Hemegovina. The old distillation plant was destroyed in the war, but after the war it was renewed and for a short time worked at full capacity. The exploitation of oil shale was done with strlp mining, and the mining was done partly by Croatia, and partly by Bosnia-Herzegovina inside the ichthyological dolomite zone.

In Vrelo KoreniEko there are two deposits of Upper Jurassic kerogenous rocks: Zubovib Draga and Mrsinj Grad (MilanoviCa Draga) for which mining exploration was done under Austro-Hungary at the turn of the century, and which were exploited for a short time after World War I1 up to and including 1949. Ten years ago, geological, organic-geochemical investigations were renewed again, of both the Vrelo KoreniEko and the Zavalje deposits of kerogenous rocks (S a b a n and S e b e E i 6,1984, S eb e E i 6, et al, 1990 and others), while below Mrsinj Grad exploratory prospecting drilling was canied out (S t o i s a v I j e v i C et a1 1988). It was found that the organic matter content changed both vertically and laterally (0.06% - 6.57%, exceptionally 68.42% ("kerogeonoides") which was rather strikingly visible from the lower thermal values of th_e drilled kerogenous rocks of Mrsinj Grad (0 to 17,401 Wkg, x=1986, 10 k.J/kg; 52 samples from 7 drills, S e b e E i C et al, 1989).

Since energy is an important input in the production o brick (40% )in 1989 we attempted to determine the technical and economical aspects of the first industrial application of oil shales in Croatia as follows: 5% or 10% mass of oil shale i.e. mass of kerogeonous dolomite and kerogenous chert from the ZuboviC Draga deposit by Vrelo KoreniEko was mixed into the raw material for brick production at Zagreb Brickworks.-The preliminary industrial testing with (3%-5%) oil-shale with a lower thermal value of 1421 kJ/kg, and industial testing with 10% oil shale with a lower thermal value of 1250 k.J/kg produced a hollow brick of dimensions of 250x190~140 mm grade 15 and grade 10. An economic analysis based on prices in January 1988 showed that it was profitiable to use oil shale as an addition if it had a lower thermal value of 3767 U/kg (3 e b e E i C et al. 1989) which could be provided only by a smaller selected part of the oil shale, and so these mining and geological explorations were abandoned. Only a shorter transportation route to closer brickworks, in PeruSiC for a m p l e , could justiFy the use of oil shales of lower energy values.

In Postak in Lika kerogen sediments are registred in the south, west and north wing of the brachysyncline which has been photogeological countoured by J a k i C (1984). The kerogenous sediments extend for 17 km in length, and their thickness is 30(- 50) m. These are Upper Jurassic kerogenous limestones - biomicrites, and more rarely fossiliferous rnicrites and cherts alternating, and dolomites. Only the regions of DimiCi and Vagan are somewhat richer in organic matter. For example, the C org content in DimiCi samples varies from 1.93% to 7.12% (x=4.38% from 19 samples).

According to T d g reserves amount to 2000000 tons (C u b r an i 6-A j d u k o v i C, 1981), in the region of RastiCevo that is, or Mijina Glava, where in 1949 exploratory works were carried out for the purpose of starting up open cast mining. P e t u n n i k o f f (1938) had already shown that there were richer regions with more organic matter, in Lisine and Viline PleCine (Vagan); he calculated excessive reserves of bituminous shales for the whole deposit (900 million tons). Pdtak is a large deposit, but largely of low quality raw material.

A kerogenous occumence in Vagan, in the village of G. TiSkwac in Lika was known before World War I1 (P e t u n n i k o f f, 1938). It is composed of Upper Jurassic Lemd sediments, largely slumped and laminated dolomites with quartz nodules. A component part is made up of the kerogenous lenses the length of which is estimated at 10 m - 12 m. In The lenses there are kerogenous siltstone with radiolarians. There is more free bitumen in the dolomite (5.24%) than in the siltstone (0.67%). The total organic matter in the analysed dolomite amounts to 49.38%.

I. Ukich, surveyor and mining entrepreneur from Sv. Juraj (St. Georg) in Styria had registered explorations and mining in Lika, and obtained ditching licenses in GospiC (BruSani, Medak, Smiljani), Perusit (Kosinj), GraEac, Donji Lapac and Srb. After a certain time &&:kov2 from "Royal Mining Captaincy" from Zagreb sent on Nov. 12, 1882 a question to the "Royal Distnct Court" in Zagreb asking it to find out if the given communes Ulrich had actually done mining. On the same date he also sent an enquiry to "Royal Tax office" in Gospi6 Grahc and Otohc and to see whether Ulrich had paid the ditching taxes, especially the arrears for the 3rd quarter of 1882. From the one answer preserved, from Grabc, it could be concluded that Ulrich did not doing any mining there.

By investigation into the fossil fauna of Dalmatia, M a r g e t i C (1952) showed that there are several working levels "of sedimented bituminous (i.e. kerogenous) rocks" of Upper Jurassic, Upper Cretaceous, and Tertiary provenance. Thus he called into question the older opinion of the Viennese geologists that the origin of asphalt should be sought in the Upper Jurassic limestone plates. The environment for the creation of the mesozoic (kerogenous) sediments according to M a r g e t i C (1952) was marine, of the older tertiary sediments brackish, and of the younger tertiary lagoonal. a h n a z a r o v (1941) had even earlier noticed differences in the genesis of the bituminous rocks of BraE, and as well as natural asphalt, saying that there are pyrobitumrnous rocks, as M a r g e t i C (1952) and later K r a n j e c et al. (1964) were to call them subsequently, sedimentary bituminous rocks lying in two working levels with natural asphalt coming between them.

In connection with the sedimetary bituminous rocks of BraE, K r a n j e c et al. (1964) conclude that because of their greater plasticity within the thickly layered limestones they are secondarily disturbed, that is, micro folded and micro faulted and crushed. Mainly they are charactenzed by a fine-layered, later called laminated, structure, in which there are alternate layers of carbonate and bituminous rocks. In the bitumen it has been microscopically determined that there is an alternation of lighter and darker leaf formations and "irregular speckled agglomerations and smaller dark dots of unclear origin (i.e. kerogen)". A migration of lighter coloured bitumen into the veins and reticular accummulations was noticed, and also into the rhombohedra1 pores in the dolomites.

According to M a r g e t i C (1952) there was intensive miniig on Brae (Brizi and DujiCevo), DreZnica (MiriloviC Polje), BiteliC and Vrdovo and UniSte. In palaeogenic kerogenous Upper Cosina limestones, bituminous marls, of Plana a tunnel of 120 m in length was made, and a number of shallow shafts. In AntunoviCi two shafts of 2 - 7 m in depth were made.

According to Schlechan (F o e t t e r 1 e, 1851) in the roof of the main coal floor layer at SiveriC in the Barbara shaft there are bituminous marly shales, although no description was given. It was establised that the stinking kerogenous limestone or shale from Kremena in the vicinity of the Neretva contains 52.7% ash. By distillation, 23-26% tar oil was obtained from it (An o n y m o u s. 1873).

In tertiary sediments oil shales were discovered in Rude, and here, according to T u C a n (1925), a mine was established in 1898. The gasworks in Split used the oil shale from Rude to make gas for lighting and for tar. After World War 11, for a short time mininig and geological explorations were resumed, and the reserves were partially calculated to be 2.3 million tons (S e f, 1956). An estimate of part of the reserves for the southern part of the syncline was based on the results of 4 drillings over a surface of 1,500 x 1,500 m, with a thickness of ore of 2.4 m; thus reserves of 1,800,000 m3were calculated. Analysis of 4 samples of the nucleus by the Fischer method determined that there was 6.7% to 18.7% oil (x=12.5%). T a k S i C (1948) estimated the total "coal" reserves of Ruda near Sinj, that is of oil shales, of 360,000 t; however he considered that at least 25% of the reserves had already been removed, and so only 270,000 t remained. The least favourable variant gives only 100,000 t of raw material, and if 25% has been extracted, this leaves only 75,000 t of material. He quotes the opinion of miner A. Polaska who thinks that the coal layer in the mine was about 1 m thick,and that there were 4 working levels which were linked by a dip heading. According to PefruniC (1951) the "bituminous shales" of Ruda constituted a "first class facility with good amortization". The use of the shales in the cement industry was being thought of here.

Of the older mine workings, nothrmg has remained that is accessible, for the works were ruined or filled in, just as the entrance to the last tunnel was filled in right next to the village lane (Fig. 19), where I myself measured a 5 m thick zone enriched with organic matter in which dark and light coloured laminae alternated. The darker laminae were rich in kerogen, while the lighter laminae were poorer, or almost without kerogen.The organic matter was immature, and so thee rocks must be excluded from petroleum-bearing rocks (S e b e E i C and E r c e g o v a c, 1983). In part of the kerogen zone in Rude a great fish farm has now been built which in part reduces the opportunities for exploitation. Because of the steepness, the layers and the undefined depth of the slope, it was questionable how economic it might be to resume extraction from these kerogenous deposit.

Of the kerogenous deposits on Dinara. I would lay emphasis on those on Golo Brdo near Vrdovo. These were explored in the fifties of this century (M a r g e t i 6, 1952, F i 1 j a k, 1951), and again only a few years ago (3 e b e E i C and S 1 o v e n e c, 1990). Their srgnificance is for the present more important from sedimentary, petroleum-geology and mineralogical than from economic reasons. About 200 t of raw material was processed in so called "mailers" in Sinj up to 1951, and gave good quality oil. The quality the raw material of kerogenous rocks can also be estimated according to the upper thermal values. It has thus been determined that better quality matertal (from 2.500 to 4.800 kJkg) is largely linked to kerogenous occurrences 2 and 3, that is to stromatolitic carbonate rocks.

The kerogenous deposit Trlji in Istria was discovered during the French occupation of the peninsula, and it was mined by the Italians with test shafts of between 7 and 8 m in depth, between the two world wars. Research was resumed only 10 years ago (V u E k ov i C and S r n i C, 1983 and S e b e E i C el al, 1990) These kerogens are Cenomanian, partially stromatolitic, limestones 2 cm - 3 cm to 70 cm thick, in a limestone zone of 5 m thickness. A very variable pyrolized-organic matter content has been determined (0.43% - 20.74%, x=6,31%, from 12 samples) and a variable upper thermal value content (92kJkg-6338kJkg, x=2143kJkg from seven samples).

In Rebifi, 5.5 krn south of Barban in Istria are Upper Cretaceous weakly kersenous limestones with 0.19% to 0.66% total organic matter (x=0.34%, N=9), in places with a little bitumen. Pyrolisis of organic matter at 550~~1m10in , by which the total organic matter content was determined, and pyrolisis of organic matter at 350'~ for 20 min, by which bitumen content was determined, was performed by chemical technician B. Stipak

According to the tabular report of Garapia and Pantz 1804 (E r c e g, 1992) it was correctly concluded that existence of "tar" at depth would not repay the trouble of digging out the ore, but the name of the occurrence was incorrectly noted as Sebische instead of Rebische. For this reason this occurrence near Barban was forgotte?, and was not noted on the Basic Geological Map, Labin Sheet (S i k i C et al, 1969). Yet the adit (Fig. 22) has remained preserved; it is assumed to be about 150-200 years old, with dimensions 5.5 mx 1.6 m x 1.85-1.05 m. In it there are Touron plate limestones with small kerogenized foraminfers. In the limestones there are kerogenous spots of 0.05 rnm to lmm in size, in the micrite basis of fossiliferous micrites (M-w) and biomicrites (w). Bitumen traces are contained in samples, alongside the fault. The organic-kerogenous matter is similar to coal, and is found mainly in the coating of fissures. In 1927 there was an unsuccessful attempt by the Italians to resume exploration by digging a trench.

New knowledge obtained from mining and geological exploration into bilnminous and kerogenous deposits

On the basis of knowledge so far gained about the mining and geological exploration of bituminous rocks in Dinarid Croatia, author proposes that in the "Special criteria for the determination and categorization of the reserves of individual solid mineral raw materials" of the "Regulations about gathering data, the way of recording and determining the reserves of mineral raw materials and proving reserves" (N a r o d n e n o v i n e, 1992) bituminous should be distinguished from oi1,that is kerogenous rocks.

It is possible to divide bituminous deposits in accord with the Regulations into three groups with respect to their various degrees of infiltration into and impregnation of rocks with hydrocarbons, that is, with bitumen. I place in the first group of deposits those with >300 x lo3 t of bituminous rock mass, into the second grou ? with from 100 - 300 x lo3 tons and into the third those < 100 x 10 tons of bituminous rock mass. Division into sub-groups is possible, but only after wide-ranging mining and geological investigation. For the exploration of bituminous rocks, proposed the following longest distance between drilling and mining exploratory works according to category of reserves (Table 2).

It is not yet defined how great the share of individual reserves in total reserves is, but author proposes, that A+B reserves constitute 60%-75% (with the proviso that A reserves constitute 2/3 of A+B reserves), and that C1 reserves make up 25%-40% of all reserves.

In order to calculate the potential reserves (C2, Dl and D2 categories) one first has to calculate the coefficient of productivity in detail of the explored region (balanced with A-Cl reserves), and the relation between the total bituminousness of the sufraces by which the categories of potential reserves are estiamted and the (total) bitiminousness of the surfaces which are explored in detail as a corrective factor for an estimation of reserves.

According to the present state of explotat~on,w hich is on the whole low, because it is mainly based on an estimation of potential reserves, most prospected or even partially invest~gated deposits would fall within the third group of deposits. The second group would include the ViniSCe-Biskupija deposit, and it is assumed that Vrgorac-Paklina would come in the first group, insofar as the great reserves are confirmed by subsequent mining and geological explorations.

Depending on the quality of the raw material, that is mainly on the bitumen content, the use of bituminous rocks is possible. For road building a fairly high content of bitumen is useful >5%, that is, 6%-10% or 7.5%-12.5%, while the bitumen content for infill has practically no lower limit. I proposed a bitumen content of 1%-2% in rock as a conditional proven reserves limit, and >2% as a proven reserves quality.

I have placed kerogens, that is oil rocks, in three groups with the essential rider that if type 1 (sapropelic) or type 2 (sapropelic-humus) kerogens are found in them, these are oil shales, while if type 3 is found, humus kerogens, then these rocks should be called coaly shales.

In kerogenous shales, kerogen can be more or less un~form concentrated in the whole rock, that is, these are homogenous oil shales; these are rarely found in Croatia. Kerogen is most often found in laminated or thinly sheeted sediments alternating with similar but barren sediments with very little or no kerogen, and finally, in layered-lensed accumulations. I disinguish our kerogen deposits according to size; the first group is composed of deposits of 3 x lo6 t of kerogenous rocks, the second of those of from 3 x 10' to3 x lo6 tons of kerogenous rocks, and the third groups contains deposits of <3 x 10' tons of kerogenous rocks. The kerogenous deposits of Postak, it is supposed, could for example be pit into the first group, Vrdova- Golo Brdo Into the second, and Braca-Brizi into the third. According to our understanding to date, only a small part, for example l/l0 of kerogenous rocks from deposits that have been studied could be used as sources of powcr (for example, the kerogen deposits in Vrelo Korenitko).

Whit respect to the largely low thermal value of the tested average samples of parts of the deposit of Mrsinj Grad in Vrelo KoreniCko (x=1986, kJkg from 52 samples) ~t has been established that the rocks investigated can be used only as a source of initial energy for the onset of combustion (1650 kJ/kg). For this reason our low energy kerogenous shales can be used only as filler In asphalt systems.

For the investigation of kerogenous rocks, I propose the following maximum distance between drilling and mining exploratory works according to reserve category (Table 3). These distances are quite close to the distances determined for the exploration of bituminous or oil rocks (N a r o d n e n o v i n e, 1992). For exploring lenticular kerogenous deposits, destances between drilling and exploratory mining works, it is appropriate to use those that are used for b~tuminous deposits. The same holds true for mixed bituminous-kerogenous deposits (Gornja RoSca and Novska-Paklenica).

During geological exploration and charting of occurrences of rocks enriched with organic matter (wth bitumen and/or kerogen), the greatest geological risks exist during estimating the geological potential (C2 or D) reserves, for there is a lack of min~ng and geological exploratory works. These risks can be reduced by investing in exploration. As well as geological there are considerable economic risks. The cost of industrial bitumen rises or falls with the changes in the price of oil on the market. That is why, before a decision about exploitation is made, a cost analysis should be made for obtaining 1 ton of natural bitumen from asphalt, and 1 ton of bitumen from 011, or perhaps the price of 1 ton of natural fillterwith organic matter, and 1 ton of industrial filler of the same composition.

Further, account should be taken of exploitational risks. F~rsti,t has to be found out whether with previous criteria (N a r o d n e no v i n e, 1992) we can with cartainty count upon the reserves that we wish to determine and secondly whether with the proposed new criteria about the minimal distance between exploratory mining works (Tables 2 and 3 in this work) it is economically justifiable.

On the basis of mining and geological, and geophysical data about the thickness of bituminous occurrences or deposits, and the thickness of the outcrops I have approximately estimated the reserves of the most important Croatian occurrences and deposits. Most occurrences contain 5-10000 t of natural asphalt, and only a few deposits have reserves of >80000 tons (Table 4).

Among the most important deposits in Croatia are Paklina, near Vrgorac, Vinisce Biskupija, Primorski Dolac - Balovi, Donji Dolac, G. RoSca and others, where exploitation has been halted. Some deposits should be worked on in a more detailed way from mining and geological points of view, as for example in the Mosor bituminous zone (Donji Dolac - Okkruglice and Misetin Dolac), and in the Biokovo bituminous zone (Kozica, Vranjesi and Grljusici).

As far as the "oil shale" deposits are concerned, or kerogenous sediments, the most interesting are in Ruda, near Sinj, and Vrelo Koreni£ko (Zubovica and Milanovica Draga). In Ruda, underground exploration was halted, while in Vrelo Korenifiko it was started, and stopped. Of those deposits that have been opened up and closed down, it would ve interesting to explore those on BraC (Brizi) and Dinara (Vrdovo), for they contain elevated organic matter contents, that is kerogen, and with them elevated thermal values of the raw material. It can be concluted about most of the occurrences that it would be irrational to explore them at present, for they contain mostly low organic matter contents. The biggest kerogenous deposit in Croatia, Pos'tak, also comes within this group. It is estimated that the geological reserves of the mentioned biggest deposits (Table 5), go up from 300000 to 2300000 tons, while smaller deposits (on Brae) have about 60000 tons.

Transforming resources into reserves

As well as finding new deposits of bituminous and kerogenous rocks, it is also important to transform the resources in some occurrences into reserves. It is not easy to find new deposits, and it is linked largely with mining and geological, organic chemical and technological investigations of the raw materials of some already well known and promising occurrences or for the discovery of entirely new occurrences, which is a much less frequent matter.

The transformation of resources into reserves happens in connection with very promising occurrences where conditional proven reserves have been determined, or where one-time abandoned deposits with lower quality raw material are reactivated for exploitation. The transformation itself is a dynamic process (Singh, 1984) and in most cases is associaded with new technologies for the application of material with a lower useful component content. This is the case for example with bituminous and kerogenous rocks and their applications in fillers in road building systems, and esepcially with kerogenous rocks (oil shales) in connection with their use as special oil lubricants (Enciclopedia italiana, 1949) or their combustion in fluidized layer such as low calorie coal and carboniferous sediments, or even for combusion in a Sterling motor (accorrding to the oral communication of Prof. Abramovii). Furthermore, the waste heaps of coal and oil shales are interesting for the purposes of fertilization and also for being recultivated and being used for economic and other purposes. In oil and/or gas fields with existing drillings it is possible to bring about the de-gassing of drilled coal layers, or kerogenous sediments. Methane gas can also be obtained from mines where there is for example coal, or carboniferous sediments and so on.

Discussion and conclusions

It is well known that bituminous rocks (natural asphalt) and kerogenous rocks (or oil shales) are enriched with organic matter. In Croatia these are largely carbonate rocks: limestones and dolomites, with a smaller amount of sandstones, siltstones, shales, cherts and others. The soluble bitumen and/or insoluble kerogen content from which oil is obtained can vary considerably, which affects changes in the quality of the raw material and the size of the deposit. Depending on the bitumen and/or kerogen content in the total organic matter or in the rock the investigated rock can be categorized as bituminous, if it contains >50% bitumen in the total organic matter, or kerogenous if it contains >50% of kerogenous matter in the total organic matter. The following division can be made if account is taken of the existence of one or two hybrid rocks (Fig. I), and practically a tripartite (as in this work) or four-part division can be made, as in the division of hybrid carbonate rocks which I published in 1983. In accord with this it is possibel to distinguish "kerogenous bitumenous rock" or "bituminous kerogenous rock". In accord with S c h m i t /.' s division (1986) it is possible to divide organolites into: pure bitumen, bitumenides, bituminous rock, or pure kerogen, kerogenides, kerogenous rocks.

By mining and geological research into the bituminous and kerogenous deposits in Croatia, I have come to the understnding that it is necessary to use special criteria to evaluate bituminous and particulary kerogenous deposits, because one is similar to bauxite deposits, and the other to coal deposits. That is why I adopted the distances between exploratory works (Tabes 4 and 5) to Croatian reserves (A, B, Ci). As far as bituminous reserves are concerned, I distinguished three groups, with reserves >300 x 10 t, 100-300 x 103 t, and <100xl0 t, and with kerogenous deposits another three grups of reserves, > 3 x 106 t, 3 x 105-106 t and <3xl0 t. For the exploration of bituminous-kerogenous and lenticular kerogenous deposits the same distances between drilling and exploratory mining works that are applicable in bituminous deposits are suitable. Before a decision about the exploration and exploitation of some old deposit is made, the exploitational and economic risks should be properly analyzed.

Since data are not available about the exploitation of natural bitumens in Croatia in the middle ages, all considerations about the possible amounts of pitch obtained in this period take on the character of more or less adequate hypotheses. I presume that bitumen was in fact obtained from deposits close to the sea like that in Vinisce, on the island of Brae (Pucisca and Skrip) and in the vicinity of the river Neretva (Paklina). Vinisce might have been a port for the construction or repair of boats, as is witnessed to by its suitable location between Sibenik and Split and by the remains of pillars in the sea in the Vinisce bay. Since ancient times natural bitumen or pitch has been recorded as being used for the hydroinsulation of ships and boats, in lubrication, in building, in defensive actions during the siege of cities, in sea battles with "Greek fire" and so on. Pitch could be used from one's own deposits, or imported, or perhaps tar could be used gained from the distillation of wood.

The history of the mining of bituminous or asphalt deposits in Croatia is more than 400 years long. According to M a t t h i o 1 i (1565) we can conclude that of the oldest deposits in Dahnatia is to be found in the vicinity of the mouth of the Neretva. It is necessary to emphasize that another very old deposit is found in Vinisce not far from the sea (now called Opatija), and in the hills (Biskupija), and also on Brae in Skrip and elsewhere. In Pannonian Croatia the oldset deposit of bitumen, or of oxidised oil, is noted in Peklenica in Medimurje. It was in the middle of the 19th century that intensive exploration for asphalt began in the Mosor region (Krivi Dolac), with exploration of asphalt in Vinisce having been renewed slightly earlier, in Opatija, when the first "factory" for asphalt processing was up. Asphalt production reached a peak at the end of the 19th centuiy.

Mining of kerogenous deposits, or "bituminous ("oil") shales" earlier called "stone" or "fossil" "coal" was begun over 200 years ago at Smirca on Brae, for which the credit should be given to the Croatian explorer/. Bilic (Billio), who played a large part in the exploration of Promina and Skradin coals. "Stone coal" from Brae was taken to Rijeka for the needs of the sugar refinery there. "Oil shales" were soon discovered in Istria too (Trlji), in the Sinj field, in Slivno (Kremena) and in the middle of the 19th century in Brae once again (Nerezisce, Splitska and Mirca). The most important period for oil shales in Croatia is connected with the beginning of their processing in Baljevac and Sinj at the beginning and in the middle of the 20th century.

There is a good deal of discussion of "oil shales" or, as it would be better to call them, kerogen sediments, particularly during the time of energy crunches or increased needs for power, in periods of world wars, economic and political blockades, new jumps in the price of oil and gas on the world market, and when there are no new reserves of basic sources of energy. They are little used at the moment because shale derived oil cannot yet compete with cheaper petroleum. For this reason kerogen sediments, as an alternative source of energy, must be left to the future.

As mining requires financial investment for exploration, and a considerably greater investment to extract the raw material, many plans or inititated explorations were halted for neither in the past nor now have there been suitable investors, big capitalists like Baron Rothschild in the 19th century who went on with works that had previously been abandoned, as in Vinisce and Vrgorac, or began them himself, as was the case with the coal mines in Siveric and elsewhere. Another problem was that even if local people had had the capital, they did not have the required expertise to carry on large-scale works. The situation unfortunately has not greatly changed in the 20th century. As a rare example, we ought to mention the surveyor A. DeSkovid from Omis (A d r i a t i c u s, 1905), who took upon himself the building of a hydroelectric power plant "Gubavica" (Kraljevac) at the falls the river Cetina in Zadvarje (1912), encouraged by French and Italian capital and experience with construction of the first such power station "Krka" on the river Krka (A. Supuk and V. Meichsner, 1895 from Gari-bovic and M o s e r, 1995) Deskovic's aim was to use the energy obtained to build up the coal and asphalt industries of Dalmatia at the beginning of the 20th century

In Croatia today not a single bituminous or kerogenous deposit is being exploited. With smallish interruptions for world wars or exploration, exploitation went on the longest in the region of Vrgorac in Paklina and in ViniSce in the deposits of Opatija and Biskupija. All the other deposits are smaller in size and have been explored and exploited for a shorter period of time. Exploration and mining was done in various separate phases, as social systems and needs changed. Among the Vrgorac deposits, Paklina was exploited right up to =1986. It is necessary to say that mining exploration was mainly of a prospecting nature, while only a few deposits had mining exploration done in detail, including the asphalts of Paklina, Skrip, Vinisce and Donji Dolac, and the oil shales of Ruda near Sinj, Vrelo Korenicko, and Baljevac. Geological opinions about the chronostratigraphic origin were given, about the position and the way in which the deposits appear, about estimates of reserves, the quality of the raw material, and exceptionally about the physical characteristics of the rock that contains organic matter. Occasionally there has been discussion about the genesis of the organic matter, and in more recent times about the petroleum geology features of rock in which organic matter has accumulated primarily or secondarily.

Only a few deposits have been covered in detail by mining and geological explorations: the bituminous deposits of the Trogir region - Vinisce-Biskupija and Nin&vica Lokva in Radosici one bituminous-kerogenous deposit from the Mosor region (Gornja RoSca, D. Dolac) and one from the Slavonian region (Paklenica near Novska). Since there were only preliminary chemical and physical-chemical analyses tests done on the bitumen and the rock mass only a brief view into the possibility of applications was obtained, including for filler for asphalt mixtures and such like; however, natural asphalt should be investigated with much more technological thoroughness to find a way of using it to the full.

Geological and mining exploration of kerogenous rocks, of the so called oil or bituminous shales, were begun only twenty years ago, for Vrelo Korenicko in the area of Licka Pljesivica and for Dimici in Postak, so that at the present time it is not possible to estimate the potentials of these raw materials in Croatia for possible use. The first explorations gave modest results to do with raw material quality, so that we can at the moment only recall that with the old technology (the "mailers"), probably from selected raw material, a certain quntity of crude oil was obtained in Ruda near Sinj. This may be connected whith the once highly valued healing properties of a preparation obtained from oil extracted from the ichtyol-shales of Baljevac, i.e. Pljesivica.

On the basis of explorations made to date of the bituminous and kerogenous rocks of Dinarid Croatia and analytical data regarding their quality it can be concluded that in the Dinarids of Croatia almost 173 smaller and larger deposits have been registered. Of these, 42 belong to bituminous rocks, 20 to bituminous-kerogenous rocks, and 111 to kerogenous rocks. According to raw material quality, selection has been made among the localities mentioned, and about 30 deposits distinguished, while most localities have been classified as occurrences.

Of these 30 deposits, 15 are bituminous, 13 kerogenous, and 2 bituminous-kerogenous. It can be assumed that about one half of these 30 deposits might be interesting for future mining and geological exploration. The high ratio of occurrences to deposits (6:1) in both bituminous and kerogenous rocks shows high variable the quality of the rocks tested is. Bituminous deposits in Croatia feature a variable bitumen concentration, with bitumen bodies of small dimensions. For this reason the exploitation of bituminous bodies should be organized in such a way as to encompass a number of similar deposits in a single area. The required bitumen content can be achieved by mixing materials with various bitumen contents, and if necessary by addition of industrially prepared bitumen. Further, it is necessary to bear in mind that only exploitation which is not expensive, or burdened by heavy transport costs to the place of use, is justifiable. This goes also for the low-energy "oil shales" which could be used in the brick industry and the cement industry, as an energetic and raw material supplement.

Acknowledgements

Certain Italian texts from archival documents were partially translated by Ms L. A n t o n o v i c, from the INA Research & Development, and Mr R. S a r z i, from the Zagreb Italian Cultural Institute, for which I give my heartfelt thanks.

References

LITERATURA

A b r a ha m, H. (1960): Asphalts and allied substances. Vol. 1 (Historical review and natural raw material). Sixth Edition, p192-193. D. van Nostrand Company INC. Princeton, New Jersey, Toronto, New York, London.

Ad r i a t i c u s (1905): UskrsnuCe novih industrija na cetinskom vodopadu kcd OmiSa. "Industrija", 1936-1937, TShnski Lloyd, 111,125, Trst

An o n i m u s (1873): Bituminiiser Kalk an der Narenta (Notizen). Oesterreichische Zeitschrifi Berg und Hiinenwesen m,49 , p. 394, Wien.

An on i m u s (1920): Erdolfunde in Kroatien. Petrolewn Zeicschrih XV4 23, 781, Berlin-Wien.

An o n i m us (1923): VrgoraEki asfalt. Priroda, 226, Zagreb.

An o n i m us (imectu dva svjetska rata): "Ihtiolski uljni Skriljac i proizvodi koji se izvadaju putem destiliranja pri niskoj temperaturi". Prijevod, Fond struEne dokumentacije INAProjekta, pp. 7, Zagreb.

B a u E i 6, F. (1943): Dalmatinski asfalt. TehniEki vjesw 60,9-10, 307-311, Zageb.

B e 11 o s z t en e c z, J. (1760): Gazophylacium latino - illyricum, p. 1288, Zagabriae. Pretisak izdanje "Ognjen Prica" Karlovac, 1972.

C u b r a n i t - ~ j d u k o v i ~ , ~ ( 1 9 8 1 ) : ~ r i l o g p o z n a v a n j u Skriljavaca u Hrvatskoj. Nafa 3512 627-631, Zagreb.

D u r a n d, B. (1980): Kerogen-insoluble organic matter from sedimentary rocks, p. 22-26. Institut Francais du Petrole, Paris.

E i c h I e i t e r, C. F. und H a c k I, 0 . (1920): Arbeiten aus dem chemischen Laboratorium der Geologischen Staatsanstalt, ausgefiirt in den Jahren 1913-1918. Jahrbuch der Geologkhen Reichsanstalt, 69 (1919), 3, Wien.

E n c i c l o p e d i a i ' t a l i a n a di s c i e n z e , I e t t e r e ed a r t i (1949): Asfalto, p. 826-829, Roma, Centro culturale italiano, br. 2078, Zagabria.

E r c e g, I. (1992): IzvjeStaj o mineraldko-rudnim IeZiStima na podrutju Dalmacije i Istre (1804). Acta histon'co-oeconomica 19(1) 105-113, Zagreb.

E r c e g o v a c, M. (1990): Geologija uljnih Skriljavaca. Gradevinska knjiga, p.p. 180, Beograd.

F o e t t e r I e, F. (1851): Vexzeichniss der an die k.-k geologische Reichsanstalt gelangten Einsendungen von Mineralien, Gebirgsarten, Petrefacten u. s. w. Jahrbuch der kk Geologischen Reichamtalf2/4,135-148, Wien.

F o r m a 1 e o n i, V. (1786): Topografia Veneta, 2, p.273-274 Venezia.

F o r t i s, A (1774): Viaggio in Dalmazia. Prijevod Mate Marasa "Put po Dalmaciji", p.p. 303, Pretisak: Globus Zagreb, tisak Delo, Ljubljana 1984.

F r i e s e, F.(1852): Die Bergwerks-Production der dsterreich~schen Monarchie: Asphalt, p. 21, pp. 52, Verlag von Fr. Manz., Wien.

F r i e s e, F. (1858): Die Bergwerksindustrie von Dalmatien, ?.Wien.

G a r i b o v i 6, F. i M o s e r, J. (1995): Aspekti trgovatkog prava na projektu "Krka-Sibenik" u kontekstu dabaSnjih stremljenja u podruEju energetike. Medunarodni simpozij StoljeCe Hrvatske elektroprivrede 1895-1995,153-167, Sibenik.

G u S i 6, I. i J e 1 a s k a, V. (1990): Stratigrafija gornjokrednih naslaga otoka Brah. Djela JAZU, knjiga 69, Razed zaprirodne manosti, pp. 160, Zagreb.

H a u e r, F. (1850): Asphaltstein vom Berge Mossor, Sitzungen am 17. Dezember, 1850. Jahrbuch der kk geologischen Reichanstalt, 1,4,749, Wien.

JeIaska,V.&OgoreIec,B.withcontributionErcegovac, M. (1983): The Upper Cretaceous Depositional Environments of the Carbonate Platform on the Island of Brat. 4 th I.A.S. Regional Meeting, p. 108-112, Split.

J e r i n i 6, G. J e I a s k a, V. and A I a j b e g, A. (1994): Upper Cretaceous Organic-Rich Laminated Limestones of the Adriatic Platform, Island of Hvar, Croatia. Bulletin AAPG, 78, 8. 1313-1321.

J o h n, C. und E i c h I e i t e r, C.F. (1901): Arbeiten aus dem chemischen Laboratorium der k.-k. geologischen Reichsanstalt ausgefuhrt in den Jahren 1898-1900. Jahrbuch der k-k geologischen Reichsanstalr, 50 (I900), 690, Wien.

Ka n a j e t, B., S a ka E, K, i S e b e E i 6, B. (1995): NekadaSnji rudnik asfalta "Skrip" na otoku BraEu. Rud-geoL- nafi. zb., 7, 87-95, Zagreb.

K e r n e r, F. (1916): ~ b eerin ige dalrnatinischen Asphaltvorkommen. Verhandlungen der k-k geologischen Reichsrmstalt. 4, 85-96, Wien.

K e r n e r, v. M a r i l a u n, F. (1919): Ursprung, Vorkommen und Beschaffenheit der dalmatinischen Asphaltlagerstatten. Berg und Hii!tenmannisches Jahrbuch, 67,275- 308, W~en.

K i S pat i 6, M. (1901): Rude u Hrvatskoj 147, asfalti. 94-97 pp. 104, Zagreb.

KranjeqV., CrnkoviC,B. i SikiC,~.(1964):0 bituminoloSkim istrazivanjima na otoku BraEu. Zbornik radova povodom 25. godignjice Rudarskog odjela TehnoloSkog fakulteta 1939-1964,145-153, Zagreb.

L u k o v i C, M.(1936): Oil shales in Yugoslavia. The Anglo- Yugoslav Review. voL I, 1-233-37, Beograd.

M a r g e t i 6, M. (1952): Bituminozne stijene Dalmacije. GeoL vjmik 11-W (1948-1 950), 117-139, Zagreb.

M a r s c h a 1 1, A. Fr. (1856): Die Bau-Materialien des osterreichischen Kaiserstaates auf der Pariser Ausstellung Jahrbuch der k-k Geologischen Reichsamtalt, 714, p. 760-762, Wien.

Martinez.A.R., Jon,D.C., De Sorcy,G.J., Dekker, M. and S m i t h, S. (1987): Classification and Nomenclature Systems for Petroleum and Petroleum Resewes. Study Group Report, Twelfth World Petroleum Congress, p.5, pp. 1-16, Houston.

Ma t t h i o I i, P.A. (1565): Commentarii in sex libros Pedac~i Dioscoridis Anazarbei de Medica materia, Ex Offic~na Valgrisiana, p. 116, Venetiis.

N a r o d n e n o v i n e (1992): Pravilnik o prikupljanju podataka, naEinu evidentiranja i utvrdivanja rezervi mineralnih sirovina te o izradi bilance tih rezervi. Br. 48, p. 1136-1137, Zagreb.

N i k o I i C, E. (1900): Escursioni in Dalmazia. Tipografia Pietro JankoviC, pp. 140, Zadar (Zara). N o v a k, G. (1962): Rudarstvo i iskoriStavanje rijeka i rnora u Dalmaciji u XVIII stoljeh. Starine, JAZU, 52, 5-7, 12-13, 21-22, Zagreb.

P a n 1 z, J.H. und E. G a r a p i c s (1804): Beschreibung aller jener Entedeckung im Mineralreiche auf meiner Reise durch das Konigreich Dalmatien und Istrien. Hofkammerarchiv, Rote Nr. 1665, Wien.

P e d e r i n, (1991): Jadranska Hrvatska u austrijskirn i njemaEkim putopis$na. Nakladni zavod Matice Hrvatske, pp. 385, Zagreb.

P e r i E i C, S. (1980): Dalmacija uoEi pada MletaEke Republike. pp. 266. SveuEiliSte u Zagrebu - Centar za povjesne znanosti, Odjel za hrvatsku povijest, Zagreb.

P e t r u n i C, A. (1951): SpecifiEni uslovi rentabilnog prerad~vanja bituminoznih Skriljaca iz Rude kod Sinja. Nafta, 3, 14-16, Zagreb.

R a u k a r, D. (1932): NalaziSte zemnog ulja u Selnici i Peklenici. Doktotska disertacija, pp. 19+2 priloga. Arhiv Filozofskog fakulteta, br. 470, Zagreb.

Re i t t e r, I. (1926): Prilog poznavanju nekih naSih bituminoznih vapnenaca. Vijesti GeoloSkog zavoda u Zagrebu, I, 52-57, Zagreb.

R i t t e r , F . , Foe!terIe,F.undHaidingeri.W.(1855): Geologische Ubersicht der Bergbaue der Osterreichischen Monarchie. Bau auf Asphalt, pp. 222, k.-k. Central-Comite fur allgemeine Agricultur und Industrie-Ausstellung in Paris, Wien.

R u d a r s k o s a t n i S t v o Zagreb (1893-1901):Rovna knjiga (Schutf Buch V). Hrvatski drbvni arhiv, br. 111, p. 237, Zagreb.

S c h 1 a t t e r, L. E. (1968): Definition, Formation and Classification of Oil Shale. United Nations Symposium on the Development and Utilization of Oil Shale Resources. Tallinn.

S c h l e h a n, G. (1851): Gebirgsarten, Kohlenmuster und Petrefacten aus verschiedenen Localitaten Istnens und Dalmatiens, der Kreide - und der Tertiarperiode angehorig. Jahrbuch der k-k Geobgkchen Reichanstalt, 2, 137. Wien.

S c h m i t z, H.H. (1986): Biturninose Gesteine, p. 385-399. Bender F. 1986 "Angewandte Geowissenschaften, Band IV Untersuchungsmethoden Wr Metall und Nichtmettalrohrstoffe, Kernenergierohstoffe, feste Brennstoffe und bituminijse Gesteine, Enke Verlag, pp. 922, Stuttgart.

S c h u b e r t, R. (1909): Geologija Dalmacije. Asfalt, pp. 181, priijevod F. Koch. Matica Dalrnatinska, Zadar.

S i n g h, V. (1984): Transformation of Resources into Reserves through Improvements in Mining Technology and Resources Appraisal Metods. 12th World Mininig Congress, November 19-23, Technical Session I, p. 3, pp. 103. New Delhi.

S k o k, P. (1972): Etimologijski jeEnik hrvatskoga ili srpskoga jaika,Knjiga 2, pp. 700, JAZU.

S 1 a d e - S i I o v i C, R. (1939): Ruda asfalta u ViniSCu kod Trogira. Hwatskigl& 20.5, br. 118, 9, Split.

S o l d o, J. A. (1978): Rudnik obitelji LovriC i Garanjin na PeruEi kod Sinja (Prilog rudarstvu u Dalmaciji u XVIII st.). Centar JAZU, p. 349-378, Zadar, Nacionalna i sveuEiliSna biblioteka br. 511764, Zagreb.

S oh 1 e, U. (1900): Das Asphaltvorkommen auf der Insel Brazza in Adria (Dalmatien) Starigrad, p. 6, prijepis. Fond strut. dokumentacije, INA-Projekta, Zagreb.

S t a c h e, G. (1889): Die Liburnische Stuffe und deren Grenzhorizonte. Abhandl. der k.-k. geol. Reichanst, 13 B pp. 1- 170, Wien.

S t o S i 6, K. (1941): Sela Sibenskog kotara. Tiskara "KaEiC", pp. 290, Sibenik

S a b a n, M. i 3 e b e E i 6, B. (1984): Organska supstanca u gornjojurskim dolomitima PljeSivice. I jug, simpozijum, Jug. asocijacija za mineralogiju, 345-360, Beograd.

S e b e E i C, B. (1978): Classification of recrystallized dolomitized and bituminous carbonate rocks. Geol. vjesnik, 3012, 711-729, Zagreb.

S e b e E i 6, B. (1981): Bituminozne pojave mosorske zone. Zborndc radova Znamtevog savjeta za naftu JAZU, serija C, knjiga 5, 133-144, Zagreb.

S e b e E i 6, B. (1983): Prijedlog novih naziva za "bituminozne Skriljavce" s osvrtom na njihovo dosadaHnje istrativanje u nas. Geol. vjesnik, 36, 309-318, Zagreb.

S e b e E i f, B. (1984): Bituminozne pojave ViiSCa kod Trogira. GeoL v j W 37, 175-196, Zagreb.

S e b e E i C, B. i E r c e g ova c, M. (1983): Prilog poznavanju stupnja zrelosti kerogena nekih bituminoznih karbonatnih naslaga Vanjskih Dinarida. Nafm, 34(4-5), 183-188, Zagreb.

S e b e E i ~5, B. and B u I i 6, J. (1983): Bituminous Miocene poorly lithificated sandstones at Novska. 4th I.A.S. Regional Meeting, 160-161, Split.

S e b e E i 6, B. and S I ov e n e c, D. (1990): Aragonite in Kerogenous Lower Cretaceous Carbonate Rocks of Mt. Dinara. GeoL vjesnik 43, 91-95, Zagreb.

S e b e E i C , ~ . , ~ l o v e n e ci ,A~l.a jbeg,A.(1990a): Kerogen~ sedimenti Zubovib Drage iz Vrela Korenitkog. Radovi Znanstvenog savjeta za naftu JAZU, serija C, knjiga 9, 251-258, Zagreb.

S e b e E i C . ~V. iteziC,M.iKoIjenSi6,M.(1990b):Kerogene pojave Trlji u Istri. XI1 kongres na geolozi na Jugoslavija, knjiga 111,946-954, Ohrid.

S e f, F. (1956): Prilog poznavanju jugoslavenskih bituminoznih Skriljaca. NaJia, 8, 233-236, Zagreb.

S i k i 6, D., P o l S a k . A. i M a g a S, N. (1969): Osnovna geoloaa karta SFRJ, list Labin 1:100.000. Savezni geoloSki zavod, Beograd.

Su r m i n, D. (1898): Hrvatski spomenici, Sv. I. (od 1100- 1499). JAZU, voL VJ144-145, Zagreb.

T a m b u r i n i, G. (1852): Sulle piu usate coperture delle fabriche esuquelle di asfalto. Milano, coi tipi del dott. Francesco Vallordi, pp. 52. Biblioteka Fanfona-Garanin, Muzej grada Trogira, oznaka XI b 143, Trogir.

T r i n k e r, (1868): Bitumen aus Istrien und Dalmatien. Verhandlungen der k-k geologirchen Reichsansfaldt, 14, 355-356, Wien.

T u C a n, F. (1925): Asfaltni rudnici. Iz: StanojeviCeve Narodne enciklopedije srpsko-hrvatsko-slovenaEke, I knjiga A-H. Bibliografski zavod d.d., Zagreb.

V r a n E i 6, F. (1595): Dictionarium quinque nobilissimarum Europae linguarum, Latinae, Italicae, Germanicae. Dalmatiae & Ungaricae, pp. 128, Nicoluum Morettum, Venetiis, VI izdanje, Novi Liber, pretisak (p. 78) + dodatak (p. 169), pp. 198,1992, Zagreb.

Ye n, T. F. and C h i I i n g a r i a n, G. V. (1976): Oil Shale, prijevod s ruskog "Go juEie slanci", Nedra, pp. 262, Leningrad.

Z e p h a r o v i c h, v o,n V. R. (1859): Mineralogisches Lexicon fiir das Kaiserthum Osterreich, I. Band (1790.-1857.), pp. 284. Naphtha, Croatien. Wien.

2 g a I j i 6, J. (1984): Nafta na naSem tlu. Razvoj naftne privrede, 218-220, Zagreb.

2 g a l j i C, J. (1994): Pet stoljefa hrvatske nafte. INA, Vjesnik industrije nafte br. 1,22, Zagreb.

N e b b j a v l j e n ri a d o v i

B a r b a r o, A. (1670): Libro I(1669-1671) p. 291 i 291 v. Povijesni arhiv Zadar, Zadar.

B o l d u, P. (1782): Libro IV (1781-1783) p.24~-26p; p. 1-275 (r+v). Povijesni arhiv Zadar, Zadar.

GembaEev,D., Silla,A., MuftiC., OniC,D., J o j i f , D . i J o v a n o v i C, M. (1956): IzvjeStaj komisije za pregled nalaziSta prirodnog asfalta na teritoriji FNRJ radi davanja predloga po obimu geo-rudarskih istrdnih radova za 1956; p. 13+2. Vranje.

G r o s s e, A (1852): Conto Corrent zwischen der Direction der adriatischen Asphalt Werke zu Veneding, von Monat Juni 1849 b-is loten Mai, 1851. Spalato am 2ten Marz 1852, Arhiv Slade-SiloviC, Trogir.

F i l j a k, R. (1951): IzvjeStaj o pojavama bituminoznih stijena na polju Vrdovo. Fond struE dokumentacije INA-Projekta, p. 1-3, Zagreb.

J a k i 6, N. (1984): IstraZivanjwe bituminoznih Hkriljevaca podrutja PoStak. Fond strutne dokumentacije INA-Projekta, p. 1- l l + 9 priloga, Zagreb.

P a t r 1 j, D. (1975): GeoloSke prilike i sirovinska baxa asfaltnih breb IetiSta Pakline kod Vrgorca. Fond strut. dokumentacije INA-Projekta, p. 7, Zagreb.

P e t u n n i k o f f, G. (1938): Das Oelschiefer Vorkommen in der Lika, Jugoslawien. Fond strut. dokumentacije Saveznog GeoloSkogzavoda br. 1058, p. 1-11, Beograd.

P r i u l i, A (1668) Spisi op..prov. knjiga I1,p. 525, Povijesni arhiv Zadar, Zadar.

0 r e S k i, E. i D u r d a n o v i 6, D. (1983): Istrativanje bituminoznih pijesaka na podrutju Novske. IstraZno buSenje-I1 faza. Fond strut. dokumentacije INA, Projekta, pp. 1-16, Zagreb.

S e r c a n a d e, P. (1381): Naslov kutije: Petrus de Sercana (1375-1416). Dokumenti od 1375.-1390. Svetanj IIa, sveZnjiC XVII, 24.IV. 1381-15.VIII.1381 protokol 20 i p. 2v. Povijesni arhiv e d a r , Zadar.

S i 1 a, A i S i n k o v e c, B.(1955): Zapisnik o pregledu istratnih radova na asfaltne pojave u ViniSCu. Fond strutne dokumentacije Instituta za geol. istrdivanja br. 2585, p.1, Zagreb.

StoisavljeviC,M.,MatiC,J.iTadej,N.(1988): IstraZivanje kerogeno-bituminoznih naslaga podrutja Korenitkog Vrela. Fond strutne dokumentacije INA -Projekta, pp. 143, Zagreb.

S a h n a z a r o v (1940): Postojeka ashltna rudiSta , Komisijski injdtaj p. 10, Fond strutne dokumentacije INA - Projekta, Zagreb.

S e b e E i 6, B. (1977): IstraZno buSenje prirodnih asfalta u Gornjim RoScima, Fond strutne dokumentacije INA-Projekta, pp. 16, Zagreb.

S e b e E i 6, B. i T r u t i n, M. (1985): Rudarski istraZni radai u ViniSCu-Biskupija (istdno buSenje). Fond strube dokumenecije INA-Projekta, pp. 86, Zagreb.

SebeEi~,~.~ovi~-~orvat,~.,BogdanoviC,M.,iAIajb e g, A. (1989): Uljni Skriljavci Vrela KoreniEkog kao dadatak u proizvodnji opeka. Fond struEne dokumentacije INA-Razvoj i istrdivanje, pp. 52 Zagreb.

S i n k o v e c, B. (1957): Geoldko jamsko kartiranje i proraEun r e z e r~ud nika asfalta u Vrgorcu. Fond struEne dokumentacije Saveznog geoldkog zavoda, pp. 5, Beograd.

T a k S i C, (1948): Prethodni izvjdtaj o pregledu terena Ruda kod Sinja. Fond struEne dokumentacije INA-Projekta, pp. 4, Zagreb.

T o m a S i 6, I. (1949): IzvjeStaj o nalaziStima bituminoznih vapnenaca i asfaltnih pjeSEara na otoku BraEu. Fond struEne dokumentacije INA-Projekta, pp. 2 + karta polobja bituminoznih i asfaltnih nalaziSta na otoku BraEu (M 1:72 OOO), Zagreb.

V u E k o v i C, J. i S r n i 6, M. (1983): IzvjeStaj istrdivanja bituminoznih pojava kod sela Saini-Trlji (Istra). Fond struEne dokumentacije INA-Projekta, 11-C-114, pp. 11, Zagreb.