Brian Hutton

A former Irish senator has unearthed diamonds a week after discovering what is believed to be the biggest untapped gold mine in the UK and Ireland.

Professor Richard Conroy's exploration company found the precious stones after a decade of fruitless drilling at a band of ancient rocks in the Kuhmo region of eastern Finland.

In an extraordinary twist of fortune, the prospector discovered more than one million ounces of gold days ago outside the small village of Clontibret, County Monaghan, close to the Irish border.

"We've been working for 10 years in Ireland and Finland. People were beginning to feel sorry for me," said an astonished Mr Conroy.

The ex-politician began exploring the Finnish side of what is known as a craton - a large section of continental plate - after Russians discovered one of the world's biggest diamond mines on their side of the same rock formation.

The Lomonosov diamond field, which is being mined by the Russian state-owned diamond company Alrosa, is thought to be the richest in the world after the Jwaneng mine, in Botswana.

"The Russians have made huge finds on the Russian side of the craton, so we thought it made sense to look on the Finnish side," said Mr Conroy.

"It's been a long, hard business. Diamonds are difficult to find but they are looking quite good. We are very pleased with them.

"If it works out, we're looking at this running into hundreds of millions (of euro), certainly tens of millions. Diamonds are very, very rare but very valuable when you find them."

Mr Conroy's company, Karelian Diamond Resources, formally announced to the London Stock Exchange yesterday that it had recovered 67 diamonds at its Finnish exploration site, six of which are so-called macro-diamonds.

The chairman said he would not put a commercial value on the stones but their significance allows him to put down more drill holes to get a clearer idea of the scale and quality of the diamonds.

Last week, Mr Conroy announced a feasibility study had started into the economic viability of mining what is thought to be the UK and Ireland's largest untapped gold mine, in the hills of County Monaghan.

The prospector believes it could be worth as much as £450m as the price of the precious metal surges in the present economic uncertainties.