河流自然重砂法取样工作,一般是沿水系上游或沿含金的中小支谷由下而上进行。其优点是:工具简单(只要一把锹、一个淘洗盘),取样工作量小(挖浅坑0.3-0.5m深,样重20-40kg),简便易行,一个人也可以干,很快就可以直接获得近地表处的砂金信息。缺点是:由于样品取在浅近地表处,不能反映深处的砂砾层含金情况,而砂金通常主要富集于砂砾层下部靠近基岩处,因此近地表处的河流重砂测量结果,在找矿中一般只有定性意义。
The river placer sampling work, are generally small branch valley along the river upstream along the gold or the next. The utility model has the advantages are: simple tools (as long as a spade, a buddle) and sampling work small (dig shallow 0.3-0.5m deep, heavy 20-40kg) and simple, a person also can dry and soon can be obtained directly from the placer gold information near the ground surface. Disadvantage is that due to sampling in the shallow surface, does not reflect the deep gravel layer of gold and placer gold is usually the main enrichment in the gravel layer at the lower part of the bedrock near the, so the near surface of river placer mineral survey results, only qualitative significance in prospecting.
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