IVERNIA West and Minorco/ Lisheen have been given the go ahead to build its £120 million lead and zinc mine at Lisheen in north Tipperary.
The exploration group hopes to begin construction by the end of the year.
Tipperary County Council granted planning permission for the project yesterday, subject to 21 conditions, after considering the matter for eight months.
The mine will take two years to build and the developers say it will generate over 700 construction related jobs.
When the mine is fully operational, it will employ 300-350 people.
"The intention to grant planning permission follows a vigorous and comprehensive process undertaken over a number of years by Ivernia West and Minorco Lisheen," the group said in a statement.
Ivernia West managing director, Mr David Hough, said last night that they were delighted planning permission had been granted.
He said they were currently tying up deals with smelters to take between 70 and 80 per cent of the concentrates.
Discussions are also ongoing with banks concerning the debt portion of the project which is $173 million (£107.6 million), which will be financed jointly by Minorco Lisheen and Ivernia.
Mr Hough said the fact that Ivernia would be in a position to finance it jointly meant that it would get very good rates from the banks.
Coincidentally, today is also the closing day for shareholders to avail of the £41 million rights issue which Ivernia shareholders approved to partly fund the company's share in the mine development.
The company will have a debt/ equity ratio of 70:30. When the new shares are taken up, around 102 millions shares will be in circulation.
The mine has a projected lifespan of about 14 years and 18 million tonnes of lead/zinc, but the developers believe its life can be extended.
The Minister for Transport, Energy and Communications, Mr Lowry, in whose constituency the mine will be built, quickly welcomed the planning decision yesterday.
He said it followed a rigorous examination and analysis of the Environmental Impact Statement for the project.
He said the proposal represented a major private enterprise initiative which, if it proceeded, would see the conversion of an unrealised national asset into usable wealth, resulting in economic benefit to the region and the country in terms of job creation potential, foreign exchange earnings and Exchequer revenue.
Third parties have 21 days to appeal the planning decision, while Minorco Lisheen has 28 days to appeal the conditions if it wishes.
The company will consider the planning conditions over the next few days.
The mine is close to another being developed by Arcon International Resources at Galmoy, Co Kilkenny.
That project ran into vigorous and lengthy opposition from local groups, concerned about the impact it would have on their lands.
The Lisheen developers have always been conscious of this and have maintained that they would engage in a very lengthy consultation process with local interest groups.
In the past, Arcon has admitted privately that perhaps it made mistakes along the way.