mining valuable minerals from a placer by washing or dredging
placer mining 例句
英汉例句
in conducting coastal open air placer mining or shore-based well drilling to exploit seabed mineral resources, effective measures must be taken to prevent pollution to the marine environment.
露天开采海滨砂矿和从岸上打井开采海底矿产资源,必须采取有效措施,防止污染海洋环境。
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。
this primitive form of placer mining is still used in some places for panning gold.