medium and thick coal seam

• 中厚煤层

medium and thick coal seam的用法和样例：

例句

1. Introduced the prevention methods and practice experience for the sixth pit in Xingshang Coal Mine adopted longwall inclined slicing experence mining method.
   介绍了兴山矿六井采用倾斜分层走向长壁采煤法开采特厚煤层，防治自然发火的经验。