A ball mill gives a consistent particle size that is important in any ore type, Troy was able to get slightly higher recovery from sulphides that oxides using gravity only, but still only around ~50 percent. So basically grind it to very small particle size then dissolve the gold with cyanide, CIL, CIP or such then recover the gold from the solution.. The company you are talking about has a very low head grade,
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They need everything going for them and process over a million tons a year to maybe make a dollar. Our head should be at least ten times that, and that is what makes Cascavel such an attractive project, if they can get it right.