Exploration of the Rathdowney Trend during the late 1960s and early 1970s identified sporadic occurrences of lead and zinc, although the first significant mineralisation was not discovered until 1984.

Initially the mine used room and pillar methods exclusively, but subsequent modifications introduced both benching and drift and fill systems where conditions were appropriate, as a means of maximising ore recoveries.

At the same time, the mining method was designed to ensure that no waste rock needed to be hauled to the surface.

Some ore remained unmined and plans were being formulated to recover of some or all of this ore.[3] The mine finally closed in 2012.

[4] The Galmoy ore bodies are breccia-hosted, generally stratabound lenses of mainly massive sulphides consisting of sphalerite, argentiferous galena and pyrite/marcasite in different combinations.