Eden visionary Tim Smit raised the Cornish flag over the entrance to Mount Wellington mine on Monday to signify a new era for the site which has been derelict for over 20 years.

Kensa Heat Pumps, headed up by Cornishman Richard Freeborn, has just bought the mine near Bissoe, ending years of speculation over what is to be done with the £1.5m 20-acre site.

Kensa design and build environmentally friendly ground source heat pumps, some of which draw their energy from deep within the earth. They will move operations from Mabe to Mount Wellington after six months have been spent renovating the site and its extensive buildings.

Mr Smit, who oversaw the transformation of an empty clay mining pit near St Austell in to Eden - one of the most popular visitor experiences in the country - is giving his support to the project because of Kensa's green credentials.

"I am supporting this because I think the technology is absolutely first class," said Mr Smit. "The site is a very interesting one with Mount Wellington being derelict and looking for us in an area of not much labour.

"Trevithick and the mining industry had its hey day in the last 1700s. I think there is renaissance of this sort of technology on the way and I wouldn't be surprised if this company goes from strength to strength."

Company director Richard Freeborn said the new facility was needed because of the continuing growth of the business. "The move will give us world-class facilities, with ample room to grow with the market, and ensure that Kensa's lead at the forefront of this renewable energy technology is maintained.

"We needed somewhere to expand and this is a magnificent facility. The present premises are too small. From tomorrow we are building scaffolding, roofs are coming off and we should move in by the beginning of May."

The site will be used for research and development, sales and marketing and for making all sorts of ground source heat pumps, especially the larger models used in schools, office buildings and factories. Smaller domestic units are being made on Kensa's Far East production line and shipped to the UK for final assembly at the Mount Wellington site.