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Abstract
The scarce data that exist suggest that deep-sea mining will have devastating, and potentially irreversible, impacts on marine life. Since the DISCOL experiment was completed, scientists have returned to the site four times, most recently in 2015. Of the licences granted, 16 are for the CCZ, and these cover about 20% of the total area. Since Thiel's first visit to the region in 1972, scientists have explored it in much more detail. Another concern among researchers is that there are no requirements to test the environmental impacts of the giant mining machines before commercial extraction begins. Since 1970, only 12 small-scale tests have been done on nodule mining, most using a narrow, roughly 2.5-metre-wide instrument to disturb the sea floor. When it does kick off, the scene at the ocean bottom will look something like this: robotic machines as large as combine harvesters will crawl along, picking up metallic nodules and sucking up the top 10 centimetres or so of softsediment with them. Because the nodules grow so slowly, mining them will effectively remove them from the sea floor permanently, say scientists.