短語(yǔ)詞組短語(yǔ)gassy y seam 瓦斯煤層thick gassy coal seam 含瓦斯厚煤層high gassy coal seam 高瓦斯煤層high gassy seam 高瓦斯煤層gassy seam mining method [鑛業(yè)]瓦斯煤層採(cǎi)煤法 返回 gassy seam