THE VALUE of unharvested ore deposits at South Crofty could be more than £1.5 billion.
According to a report by industry experts, London-based Micromine Intuitive Mining Solutions, the mine contains almost eight million tonnes of unexploited tin, plus a selection of other ores, including cobalt, indium, wolfram and silver.
Using current metal prices, which include tin at about £12,700 a tonne, calculations suggest the mine's resources are hugely valuable.
The report was commissioned by Celeste Copper Corporation, which hopes to start ore production within three years.
Chief executive officer, Alan Shoesmith, said: "This is a report prepared by an independent expert who, under Canadian regulations, is deemed a qualified person.
"Perhaps the most important element of the report is the qualification of exploration targets.
"They are a reappraisal of remaining mineralisation after historic mining activities."
South Crofty closed in 1998 when tin prices hit rock bottom at about £3,000 per tonne.
Baseresult Holdings took over the mine, intent on restarting tin production, eventually becoming Western United Mines.
Rising tin prices in recent years, caused by increasing demand, attracted the interest of Celeste Copper Corporation.
The Canadian company, which now owns approximately 25 per cent of the mine, has identified Crofty as its number one priority worldwide. It is expected to eventually acquire a 100 per cent interest in the mine.
Next year the company plans to spend about £8 million as it works towards production.
Its 2013 programme includes pumping water from the shallow workings in the Dolcoath section of the mine, and extending the Tuckingmill decline.
The Crofty operation has attracted about £15 million of investment over the past decade.
However, it is expected to cost between £75 million and £100 million to get the mine back into full production, when more than 220 full-time jobs should be created.
During the summer, the mine appointed a new chief operating officer.
Former Camborne School of Mines graduate Chris Davie, who has more than 40 years' mining experience, said Crofty had "tremendous potential".