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Underground extraction
in mining, the retrieval of minerals from an underground deposit. Underground extraction can be either total or partial; in the latter case, separate types of ore, coal, rock, etc, are removed individually. The excavations that form as a result of such work are called chambers; the sides of these workings are called faces, and the space that forms after the extraction of minerals is called worked-out space. Blasting is used as a preliminary stage to loosen rock formations when extracting rock minerals.
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