1·This primitive form of placer mining is still used in some places for panning gold.
这种原始的砂矿开采形式至今还在一些地方用来淘金。
2·In this paper, the parametric measurement, the control method and the research on equipment in mining and mineral processing for beach placer are described in detail.
本文详细叙述了海滨砂矿采选工艺中这些参数测量及控制的方法和设备的研究。
3·Placer mining is based on the FACT that heavier substances can be separated from lighter ones in water.
较重的物质可在水中与较轻的物质分离，砂矿开采正是利用这个原理。
4·Shore REE placer is one of the most important exogenetic ore deposits of REE.
外生稀土矿床中最重要的是海滨砂矿。
5·Placer deposit is highly developed in USSR.
苏联的砂矿矿床比较丰富。