manto
n.— «Deposits of copper-cobalt-manganese-zinc mineralization at Boleo occur within widespread, stratiform clay-rich horizons or beds known as “mantos” (manto is a Spanish term used in mining parlance for a general mineralized layer or stratum).» —“Baja Mining Reports on Initial In-Fill Drilling Results of the Definitive Feasibility Study” in Vancouver, British Columbia Baja Mining Corp. July 24, 2006. (source: Double-Tongued Dictionary)