研磨石

对于牧溪谷的每个季节，该小组都已在每个地方设定了GPS，他们记录每一个具有考古价值的陶片，箭头和研磨石被发现的具体位置。

During their four seasons in Range Creek , the teams had plotted the GPS coordinates of every site they 'd found and recorded the location of every potsherd , arrowhead , and metate .

钢球的磨损率随磨机中氧气分压的增加而增大，研磨铁矿石时，增大的幅度较大：研磨石英岩和磷灰石矿时，增大的幅度较小。

The wear rate increases more rapidly in grinding iron ore than in grinding quartzite or phosphorus ore as the oxygen partial pressure in the mill is increased .

在有氧存在的条件下研磨铁矿石，由于其中的硫化矿物与钢球之间形成腐蚀电偶，从而加速了钢球的腐蚀磨损速度。

In the presence of oxygen ( oxygen or air flushed into the mill ), the corrosive wear of steel balls accelerates in grinding iron ore due to form galvanic coupling between sulfide minerals in iron ore and steel balls .