The coal ranges from a sub-bituminous to bituminous and locally will yield a low- grade coke. Copper deposits are ... Sulfur occurs in very small deposits, formed by fumaroles and springs in proximity to volcanoes of recent age. The deposits have ... During World War II, quartz crystals were procured from Boyaca, Antioquia, and several other departmentos. Some 2, 430 pounds ... Railroads and highways are costly to build and, during the rainy season, difficult to maintain.aquot; The authoranbsp;...
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