Show the mine output of gold silver copper lead and zinc california in 1912 according to charles G yale of the united E states geological survey was valued bat an increase of over the corre spending sp value for the year 1911 the increase is due mainly to a gain in yield of gold from deep mines increased value from copper and silver and increased output of zinc the greatest gain was in the value of copper and was due to an advance in commercial value of the metal as the quantity produced was materially less in 1912 than in 1911 to a less degree the same may be said of silver and the zinc quantities and values also increased |