Investors snapped up more than 7.5 million shares in dual-listed Irish explorer Minmet in London yesterday. The price rose by up to 13 per cent, after the company announced that it had struck gold at its prospect in northern Sweden.

The Dublin and London-quoted company said it had discovered deposits of 11 grammes per tonne at its property in Barsele, northern Sweden.

The find was 13m to 21m below the surface.

Reports suggested yesterday that at this depth, the relatively dense deposits could be exploited by open-cast mining, which is cheaper than extracting underground.

The company itself said that the find was "virtually on the surface and should be taken further". It added that its drilling had also turned up quantities of silver, copper and zinc.

The news sparked a surge of interest in the stock in London, with investors buying almost four million shares in the morning, and a similar amount yesterday afternoon.

The stock closed at 5.78p sterling (€8.38 cent), an increase of 13.24 per cent on its opening quote of 5.10p. A total of 7.85 million shares changed hands on the day, around four times its normal daily volume. It was unchanged in Dublin at eight cents.

Minmet said North American Gold had an option to develop the find jointly.

The American business can claim up to 60 per cent of the property if it puts up €2.8 million for further development.

Another Irish exploration company, oil and gas play, Petroceltic, made further headway yesterday after seeing its price accelerate by 40 per cent on the back of heavy buying in the closing days of last week.

The company closed in London at 6.57p, 23 per cent up on its Friday close of 5.35p. Almost 44 million of its shares changed hands.