A lead-zinc underground mine.
The orebody, Lower Carboniferous rocks, was discovered in the 1960's when significant soil geochemical anomalies were found. More surveys were conducted in the 1980's and finally mineralization was found.
The mine began production in 1997 and various satellite orebodies have been found.
The ore is breccia-hosted and forms, generally stratabound lenses of predominantly massive sulphides consisting of sphalerite, Ag-bearing galena and pyrite/marcasite.
'Room and pillar' extraction methods are used and unfortunately backfilling as well making collecting difficult.
Requests to the geology department for specimens, or access, were refused on the grounds that mineral specimens are "property of the company" and cannot be allowed off site. A policy strongly defended by the chief geologist. They seem to have had no interest in preserving their natural mineralogical heritage for future generations.
The mine closed in summer 2009. Of the three modern Irish zinc mines (Galmoy, Lisheen and Tara) Galmoy was the best for vugs and crystallised material, but for the aforementioned reasons almost nothing has been saved. The few pieces obtained from employees indicate that this mine may have been the greatest Irish mineralogical treasure trove since Silvermines.
Refs.:
- Balassone, G., Rossi, M., Boni, M., Stanley, G., and McDermott, P. (2008): Mineralogical and geochemical characterization of nonsulfide Zn–Pb mineralization at Silvermines and Galmoy (Irish Midlands). Ore Geology Reviews 33, 168-186.
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http://www.arcon.ie/s/GalmoyMine.asp
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http://www.lundinmining.com/galmoy/index.php
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http://www.mining-technology.com/projects/galmoy/28 entries listed. 27 valid minerals.
