Almost 10 years ago James Howells threw away a hard drive during a clear out - forgetting about the Bitcoin on it.
Now, with the Bitcoin worth an estimated £150m ($184m), he is planning to spend millions digging up a Newport landfill in a bid to find the lost hard drive.
If recovered Mr Howells said he would give 10% of the proceeds to turn the city into a crypto-currency hub.
But the council said excavating the site would pose an ecological risk.
Mr Howells, an IT engineer, accidentally threw away the hard drive in 2013 after mining 8,000 Bitcoins in the early stages of the currency's development.
Bitcoin fluctuates wildly in value - in January 2021, Mr Howells' was worth around £210m, but with a big crash coming earlier this year, it is now significantly less.
Newport council, which own sthe landfill Mr Howells believes the drive is in, has repeatedly denied him access to dig the site on the grounds of environmental and access concerns.
Mr Howells has now pledged about 10% of the proceeds of the drive, should it be recovered, to fund a range of crypto-based projects.
Any project to dig for the drive would require a huge manual task of digging through thousands of tonnes of compacted landfill that has been accumulated at the site for decades.
But Mr Howells believes he now has the funding and expertise set up to do it in an effective and environmentally beneficial way for the site.
"Digging up a landfill is a huge operation in itself," he said.
"The funding has been secured. We've brought on an AI specialist. Their technology can easily be retrained to search for a hard drive.
"We've also got an environmental team on board. We've basically got a well-rounded team of various experts, with various expertise, which, when we all come together, are capable of completing this task to a very high standard."
Finding the hard drive though is just part of the monumental task. There is no guarantee that, if it is there, it is even in a recoverable state.
But if it is, then its owner is set for a mega-money windfall, although the actual amount will depend on which direction the volatile cryptocurrency goes in.
Either way it is likely to be many millions of pounds.
But the 37-year-old, who has signed away some of the ownership of the coins as part of the funding process, said his donation to the city would be used to promote the use and understanding of cryptocurrency.
"We've got a whole list of incentives, of good cases we'd like to do for the community," he added.
"One of the things we'd like to do on the actual landfill site, once we've cleaned it up and recovered that land is put a power generation facility, maybe a couple of wind turbines.
"We'd like to set up a community owned (Bitcoin) mining facility which is using that clean electricity to create Bitcoin for the people of Newport."
'Significant ecological risk'
Among his other plans are proposals to give £50 worth of Bitcoin to every person in the city and install crypto-based terminals in all shops.
Newport council said it had repeatedly responded to Mr Howells requests for access to the site:
"We have statutory duties which we must carry out in managing the landfill site," a spokesman said.
"Part of this is managing the ecological risk to the site and the wider area. Mr. Howells' proposals pose significant ecological risk which we cannot accept, and indeed are prevented from considering by the terms of our permit."
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