(NEWSER) – Sitting beneath about four feet of garbage in an area of a Welsh landfill the size of a football field sits a fortune—in the form of a computer hard drive that James Howells threw out this summer while cleaning up his workspace. On it: the cryptographic "private key" he needs to access 7,500 Bitcoins. And since the digital currency hit a major milestone yesterday, with a single coin now worth more than $1,000 on the most popular exchange, that tossed hard drive is worth more than $7.5 million. Unfortunately, Howells doesn't have a firm sense of when he sent it to its resting place in the Docksway landfill near Newport, Wales, though he's been racking his brain since Friday, when he realized his error: "between June 20 and Aug. 10. Probably mid-July" is the best he can come up with.