Lead Mining started at Bwlch Glas started during the 1880's when a level was excavated to intercept two parallel veins of ore, which outcropped further up the hill. Serious production at the mine didn't start until 1909, when an impressive processing mill was constructed and other levels opened. The Scottish Cardigan Lead Mining Company Ltd. finally closed the mine in 1923, having worked there on a fairly intermittent basis for a number of years.