In 2013 James Howells of Newport, Wales mistakenly tossed his hard drive into the trash, and the next day his wife took it to the local landfill. Sometime later, he realized what happened and has been pleading with local officials ever since to allow him to look for it.
From D.T. Max's New Yorker story:
A reporter from the Guardian got wind of Howells's story. At first, Newport officials said that if they found the drive they would of course give it back, but later they adopted a more hard-line stance. How could Howells be sure that the hard drive had been placed in the landfill? In any case, they cautioned, the drive was likely unusable: it would have been destroyed en route to its noxious burial place. And, besides, the environmental risk of a retrieval would be too great.
Howells studied the technology behind hard drives and came to believe that the city officials were wrong. Although the covering of the drive was metal, the disk inside was glass. "It's actually coated in a cobalt layer that is anti-corrosive," Howells told me. He conceded that the hard drive would have been subjected to some compacting when it was layered in with soil and other trash. But, however rough the process, it might not have fractured the disk and destroyed the drive's contents. Howells told me he'd learned that, in 2003, when the Columbia space shuttle plunged to Earth, one of its hard drives was "burned to a crisp," but its data could still be retrieved. "They managed to recover ninety-nine per cent of the data," he said. At one point, Howells reached out to the company that nasa had contracted with: Ontrack, a data-recovery firm based in Minneapolis. According to Howells, the company estimated that, if the disk hadn't cracked, there was an eighty-to-ninety-per-cent chance that the data he needed could be salvaged. Howells's bitcoin folder, which contained only his private key and the history of his transactions on the network, took up a tiny amount of disk space—"just thirty-two kilobytes!" he told me. He was certain that, as long as that part of the disk was undamaged, he could recover his fortune.