coal seams

  • 网络煤层;号煤层

coal seamscoal seams

coal seams

煤层

WorldWideScience.org Topics : C ... coal reserves( 煤储量) coal seams( 煤层) coal tar( 煤焦沥青) ...

号煤层

4号煤层,No.4 coal... ... ) No.27 coal seam2 7号煤层 ) No 1 and 5 coal seams1 ,5-号煤层 ) No.9 coal seam9 号煤层 ...

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