砂金

However, panning cannot be done on a large scale, and industrious miners and groups of miners graduated to placer mining "cradles" and "rockers" or "long-toms"[69] to process larger volumes of gravel.

68然而，由于淘金盘不适用于大规模淘金，一批批勤劳的淘金者们逐步演化出用于砂金开采的&摇篮式洗矿槽&、&淘金摇动槽&或称&长型倾斜淘金槽&[69]以便处理更多砂石。

Especially the ecological environments in the Irtysh River which is the only river in China running into the Arctic Ocean have been seriously damaged by the activity of panning out gold from the sands.

我国境内唯一流向北冰洋的河流——额尔齐斯河流域部分支流砂金矿的开采已造成了严重的生态环境破坏。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。