A bit more info on Gunkanjima (the slang name for Hashima island). The mine closed in 1974, when demand for coal petered out (and prices stabilized after the big “oil shock” OPEC oil embargo of 1973). A nice article in the nifty magazine Cabinet has some testimony from a Korean guy who was mobilized to work there, and explains how it was a “company town” for Mitsubishi.
The mine was deep under the sea, the workers reaching it by elevator down a long narrow shaft. The coal was carried out from a spacious underground chamber, but the digging places were so small that we had to crouch down to work. It was excruciating, exhausting labor. Gas collected in the tunnels, and the rock ceilings and walls threatened to collapse at any minute. I was convinced that I would never leave the island alive.
The writer of the article gives some specs, too:
Indeed, Mitsubishi owned the island and everything on it, running a kind of benevolent dictatorship that guaranteed job security and doled out free housing, electricity and water but demanded that residents take turns in the cleaning and maintenance of public facilities. Thus the people of Hashima huddled together, all under the wing of “The Company” and all bent on a common purpose.
But coal is not edible. The community depended completely on the outside world for food, clothing and other staples. Even fresh water had to be carried to the island until pipes along the sea floor connected it to mainland reservoirs in 1957. Any storm that prevented the passage of ships for more than a day spelled fear and austerity for Hashima.
The most notable feature of the island was the complete absence of soil and indigenous vegetation. Hashima, after all, was nothing more than a rim of coal slag packed around the circumference of a bare rock. A movie shot there by Shochiku Co. Ltd. in 1949 was aptly entitled Midori Naki Shima (The Greenless Island).