In a dim room in Denver, drinking after a snowy SME day, I chanced on a friendly & voluble fellow: Dr. Gus Van Weert. He told me in enthusiastic tones of his work. Intrigued, I begged for a copy of his paper, “Infrared Recognition of High Sulphide and Carbonaceous Rocks After Microwave Heating”. He sent me one, and now I am honored to be able to tell you that a copy is available. Contact him at .

He is clearly an expert, and so vastly more intelligent and knowledgeable than I am in his field , that I dare not review it, comment on it, or write more about it. So to tempt you to read it all, I simply provide right here the abstract:

Ore sorting has been quite successful in providing a separation means in the rock size range of 1 to 6 inches; a range where mineral dressers do not have many options. The industrial minerals and recycling worlds have embraced this technology. However, ore sorting has not found wide application in the base or precious metals mining industry. One reason for this is thought to be the reliance of most sensors on rock surface characteristics, not very useful in the case of sulphides, non-existant in the case of gold. Microwave heating, however, is specific for sulphides and graphite (or carbonaceous matter) embedded in the rocks; washing or even drying does not appear necessary. Separation can be done afterwards by existing ore sorting technology using infrared sensors. Test results on six Nevada gold ore samples are presented in detail. Some simple test procedures are also presented for those wishing to explore the microwave potential of sulphide sorting in their own operations.

In e-mail correspondence, Dr. Van Weert told me that Barrick is interested in sorting both sulphides and carbonaceous matter from gold ores. Microwave heating followed by infrared scanning (MW/IR) does both, simultaneously, but not (yet) separately. Barrick is hopeful somebody, such as an equipment supplier, will commercialize the technology. That is not Barrick's core business. Barrick has no desire to own the technology, but has filed a patent application, so that the developer will have some incentive and protection. Dr. Van Weert is the go-between / facilitator in the latter process.