top coal meaning in English

煤层顶部煤

Fractal study on blasting energy of top coal
综放顶煤爆破能量的分形研究
Analysis on top coal caving mining technology of simple supports
简易支架放顶煤开采技术
Study on mechanism of difficult caving of highly tough top coal
高韧性顶煤难冒性机理研究
Analysis of longwall top coal caving in thick seams with parting band
含夹矸厚煤层综放开采技术分析
Ground pressure in light mechanized top coal caving face in the deep area of mine
深部轻放面矿压规律研究

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