Show from short tons of low gradl grade copper ore in maryland and pennsylvania and magnetic iron ore carrying small quantities of copper bearing pyrite in Pennsyl avnia there was an output in 1912 according to H D mccaskey of the UnIted states geological survey of fine ounces of silver and pounds of copper valued in all at the corresponding production in 1911 was valued at the maryland output was derived from concentrates produced at the new london mine in frederick county the pennsylvania output came in small part from low grade matte reported produced and shipped from charmian where a blast furnace has been built to treat the secondary copper ores of the catoctin schist but mainly from the cornwall iron mines in lebanon county where the grondahl process has been in operation for some years raising the purity of the iron ores and at the same time producing as ta a valuable product byproduct by copper bearing pyrite for sale to copper smelters shelters sm elters the total production of copper from these cornwall iron mines in the five years has been pounds 0 one hundred and four cars of concentrates were shipped from telluride station colorado during may |