砂矿开采；淘金

place kicking───n.定位踢；踢定位球

laser machining───[机]激光加工

teacher training───教师培训；师资训练

ascertaining───vt.确定；查明；探知

coal mining───[矿业]煤矿开采

data mining───数据挖掘技术（即指从资料中发掘资讯或知识）

determining───n.决定；测定（determine的ing形式）

extermining───vt.消灭（等于exterminate）

landmining───土地开采

Placer mining is based on the FACT that heavier substances can be separated from lighter ones in water.───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。

I got educated on placer mining, and heard all about the controversy over the use of water cannons.───我得到的教育砂金开采，并听取了所有的争议，使用水炮。

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。

Dredging is the most important placer - mining method today.───挖掘法现在是最重要的砂矿开采的方法.

Placer mining: Oldest method of recovering gold from alluvial deposits.───砂矿开采: 从冲积层回收黄金的最古老方法.

This paper describes basic characteristics of dredging, application of dredging technology in the world beach placer mining, and dredging future.