".The former Harvey Hill mine is located in the municipality of Saint-Pierre-de-Broughton. It is the oldest copper mine in Quebec. Its deposit discovered in 1856, the mine is exploited since 1858 by the Mégantic Mining company, formed by Dr. James Douglas (1800-1886). This mine was operated intermittently until 1981. The mining took place underground to a depth of about 120 meters. The underground network has up to four levels of depth. This deposit is very rich, it can contain contents up to 30% copper. The ore is located in quartz-calcite-dolomite veins that intersect shale."

http://www.patrimoine-culturel.gouv.qc.ca/rpcq/detail.do?methode=consulter&id=201032&type=bien#.XOdOHejYrnE