They are employed by coal, metal and non-metallic mineral mines and quarries.

他们受雇于煤炭，金属和非金属矿物矿场和采石场。

Kaolin is a very important use of a very wide range of non-metallic minerals.

高岭土是一种非常重要、用途十分广泛的非金属矿物。

The sealing ring by a similar to the rubber or plastic non-metallic materials.

该密封圈由一种类似于橡胶或塑料的非金属材料制成。

The penpoint fracture is main due to non-metallic inclusions and center segregation.

笔尖状断裂主要由非金属夹杂和中心偏析造成；

Application materials: Laser marking of metal and a variety of non-metallic materials.

适用材料：可雕刻金属及多种非金属材料。