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| lignite mining Extraction of brown coal from natural deposits; lignite is a brownish-black solid fuel in the second stage in the development of coal. It has a little over half the heating value of bituminous or anthracite coal | |||
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| lignite mining Extraction of brown coal from natural deposits; lignite is a brownish-black solid fuel in the second stage in the development of coal. It has a little over half the heating value of bituminous or anthracite coal | |||
