Tin, copper, zinc and other metals yet to be extracted from South Crofty mine have been valued at £1.5billion.
An independent report published yesterday estimates that deposits of unexploited tin alone could amount to nearly 8 million tonnes.
Celeste Copper Corporation, which hopes to resume full mining operations at the site in West Cornwall by 2015, confirmed that the £1.5bn figure was calculated on the basis of current world metal prices.
The report also stated that Celeste will be spending £7.8million in the next 12 months on making the site ready for mining. This will include £1.1m on drilling and £2.6m on pumping water from a vast network of old flooded levels and shafts.
The Canadian-owned company – which has a number of US investors – already employs 40 staff who are working round the clock to prepare the mine for full production. And hopes were high across Cornwall last night that the company's promise of some 220 full-time jobs would be achieved within two years.
Crofty's closure in 1998 was seen by many as the death knell on 4,000 years of metal mining in Cornwall. However, the dogged determination of a team led by Kevin Williams and Alan Shoesmith kept the business – and the hope – alive. Yesterday's report appears to have rewarded their faith.
Alan Shoesmith, who was appointed Celeste CEO earlier this year, said: "This report was prepared by an independent expert and perhaps the most important element of the report is the quantification of exploration targets."