A Canadian exploration company has claimed that Northern Ireland has the seventh richest undeveloped seam of gold in the world.
Dalradian Gold plans to start digging under a mountainous area of Co Tyrone next year and vowed to turn the region into a mining centre of excellence.
The firm says it has identified a 4km deposit through drilling and another 12km through scientific examination.
Chief executive officer Patrick Anderson said: "This will be a generational project; we will be here for a very long time."
The Curraghinalt deposit is ranked seventh in the world among undeveloped reserves in terms of the grade of the precious metal, Mr Anderson said.
That means the proportion of gold to rock is high so there is less cost in extracting it.
Dalradian Gold floated on the London Stock Exchange this morning. Around 3.5 million ounces of the precious metal had been identified near Gortin, Co Tyrone, under the remote Sperrin Mountains.
The firm said it is enough to sustain the local industry for 18 years.
The planning process is still to be passed so it is hard to tell what value the precious metal will eventually fetch on the market, analysts said.
Around 20,000m of drilling are due to be carried out to support planning requirements. The firm has already completed 50,000m of drilling.
Mr Anderson said: "This is a mining industry we are trying to build here. We are already talking to colleges in Omagh to put together courses to train people to become miners.
"We don't want to build a mine, we want to build a centre of excellence for mining."
The hole in the landscape will be 5m by 5m and most of the work will be carried out underground.
The chief executive added: "There will be some surface works but nothing on the scale of some of the quarries that we have seen in Northern Ireland."
Other forms of proposed underground exploration in Northern Ireland, notably fracking for natural gas in Co Fermanagh, have faced vehement opposition from local residents.
But Dalradian plans to step up consultation with local residents.
The firm launched on the stock exchange in London, on a market which is designed for less-established ventures, only the third Northern Ireland-based business to do so.
Ibukun Aiebyo, the exchange's head of emerging markets, said: "It is an astonishing feat that is testament to the work that you as a business have done and that your advisers have done, adding to the emerging potential of Northern Ireland; indeed continuing to create the jobs and the scope for industry across the country."
The firm has already been floated in Canada and this venture is designed to raise interest among investors in Great Britain and Northern Ireland.
Dalradian expects to employ 200 people eventually. Some £35 million has been ploughed into exploration and other processes. Feasibility studies are to begin next year, Mr Anderson said.
The market capitalisation or value of the firm when it floated was 80 million Canadian dollars.
Gold mining in Ireland dates to the Irish Bronze Age of approximately 2500BC.
Exploration has taken place in the Gortin area since at least the 1600s.
Dalradian purchased the mineral rights to the Curraghinalt Gold Project in late 2009 and has carried out prospecting in the area.
Mr Anderson added: "It is a very special deposit. We are confident that this will move forward."
Office of the First Minister and Deputy First Minister (OFMDFM) junior minister Jonathan Bell said Northern Ireland's level of foreign direct investment by some measures outstripped London.
He said the salaries would be around £33,500.
"These are quality jobs coming to the west, an experienced company with experienced personnel and a track record."