US2319394A - Beneficiation of low grade coal - Google Patents


US2319394A US376448A US37644841A US2319394A US 2319394 A US2319394 A US 2319394A US 376448 A US376448 A US 376448A US 37644841 A US37644841 A US 37644841A US 2319394 A US2319394 A US 2319394A Authority US United States Prior art keywords coal concentrate low grade pyrite mesh Prior art date 1940-04-05 Legal status (The legal status is an assumption and is not a …
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