Kaolin mine rock among coal is an important nonmetal mine resources of being to exploit a great deal.

煤系高岭土矿岩是尚待大量开发的重要非金属矿产。

youdao

Kaolin mine rock among coal is an important nonmetal mine resources of being to exploit a great deal.

煤系高岭土矿岩是尚待大量开发的重要非金属矿产。

youdao