2020-10-072022-02-032020-10-072022-02-03https://hdl.handle.net/11124/175258Caption reads: "18."Donor: Friends of Mineralogy, Colorado Chapter.View of the sheer sides of Iron Mask Gulch.4 1/2 x 3 1/2black-and-white photographsUnderground mining -- ColoradoMine dumpsZinc mines and mining -- ColoradoSilver mines and mining -- ColoradoStillImage