直到目前为止,加拿大所有的黄金基本上都是用重选和/或混汞法回收的。这种方法对于粗粒砂金是很有效的,但是对于较细的砂金,特别是被部分包围在基岩中的金粒则格外无效。十九世纪,在美国、南非、澳大利亚及加拿大都发现了许多大矿囊。各地区丰富的块金和粗粒砂金很快被采完,取而代之的是硬岩脉金矿,在其选矿破碎过程中不可避免的会有较细的金粒损失在选厂尾矿 Until now, all of Canada’s gold has been largely recovered by gravity and / or amalgamation. This method is effective for coarse grained Au, but is especially ineffective for finer grained Au, especially partially submerged gold in the bedrock. In the 19th century, many large mineral capsules were found in the United States, South Africa, Australia and Canada. Abundant gold and coarse grained gold in various regions were quickly collected and replaced by hard dikes and gold mines. In the course of ore dressing and crushing, there will inevitably be smaller gold loss at the mill tailings