pitching seam

- Metalloid Toxicant的日志 - 网易博客... ... pitching borer 开眼钎子 pitching seam 倾斜层 pitching vein 急倾斜矿脉 ...

倾斜煤层(pitching seam)定义： 地下开采时倾角25—45°的煤层；露天开采时倾角10—45°的煤层。