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Entry Category: Mining - Starting with B

Bauxite Mining

Bauxite is the principal ore of aluminum and is a mixture of aluminum oxides and hydroxides that formed from intense chemical weathering of a soil in tropical environments. Soils formed under these conditions are termed laterites. In Arkansas, the aluminum-enriched soils are the result of the decomposition and lateritic weathering of nepheline syenite, an intrusive igneous rock. During the weathering process, leaching by rain, groundwater, and salt spray decomposed the original syenite minerals (feldspar and nepheline). Weathering removed much of the silica and concentrated the newly formed aluminum oxides and hydroxides as the rock termed bauxite. Geologically, the soils formed from syenite and weathered to laterites in the Paleocene Epoch (65–55 million years ago) along the west edge of a …