The concern follows a decision by local councillors to abandon an appeal against a Dublin High Court judgment overturning their ban on prospecting in a 300- square-mile area.
The court ruled that Mayo County Council had no powers on environmental grounds to halt mining in the affected zone.
When the ban was imposed earlier this year, it stopped work by two mine companies which had invested more than pounds 2m in the search for a Mayo goldfield with an estimated value of up to pounds 800m. Both companies indicated they would review the project.
Paddy Hopkins, chairman of the Mayo Environmental Awareness Group, has criticised the council decision not to pursue the appeal, and warned that his group would oppose any new mining plans 'every inch of the way'.
He added: 'If the mining companies decided digging in the area was financially viable we would expect the wishes of the people to be taken into account by the planning authorities. Mining scars an area and deters tourists, and this decision puts Croagh Patrick right back into the reckoning.'
Sean McEvoy, chairman of the council, said it had already spent more than pounds 100,000 on the High Court case against efforts to mine Croagh Patrick and a site near Killary Harbour.
'It was not practical or sensible to impose a ban over such a wide area. But I would still oppose mining on Croagh Patrick. We reserve the right to halt these activities in more scenic parts.'
Croagh Patrick is the focal point for 25,000 Roman Catholic pilgrims on the final Sunday of each July. They climb the boulder-strewn mountainside, many barefoot, to worship in a small church at the summit. The pilgrimage marks the 40 days St Patrick is said to have spent on the peak in 441, praying and fasting for the people of Ireland.Reuse content