Larry, once again their coc wording is curious. They say the sample were drilled under BD supervision, but they don't say BD coc. Maybe this is not a big deal but it is reminiscent of some previous IPM dealings and press releases about BD.
I also wonder why all of a sudden the standard fire assay woks on this material. The grind to 200 mesh is no big deal. That is part of the procedure for a standard fire assay. It does not necessarily follow that any treatment method will involve 200 mesh grinding.
I doubt that this ore will be a good candidate for heap leaching. There is too much clay. Heap leaching consists of building piles of ore in lifts and spraying leach solution of the surface. This trickles through the material and is collected on a liner and transported to a treatment facility where the gold is removed. This works well on hard rock ore which is blasted and crushed and contains little clay. If clay is present, cement and water are added to the ore and it is agglomorated to cause the clay and cement to form little balls. If this is not done, the leaching process causes the clay to plug the permeability of the leach dump. However, there is way too much clay in playa material for it to be heap leachable.
If the ore does require grinding to 200 mesh, this is not cheap. This is usually accomplished with ball mills or similar equipment. Since this is done with lots of water, again the clay will cause problems. In order to handle high clay tailings a tremendous amount of thickner capacity will be required. In fact, when you start talking ball mills, thickners, tailings, etc, you are talking about a very conventional milling operation. I doubt that .2 oz per ton material would support such treatment.
Tim Hall |
