Some Excellent Reading On The Complexities Of Gold Recovery11 Sep 2020 20:20
This article talks about some of the issues Centamin faces developing Konkera/Batie West
“Unfortunately the metallurgy is often an afterthought. There’s often little metallurgical representation on the boards of mining juniors. They start off with a conceptual study, and management just assumes that they’re going to recover 100% of whatever gold’s there.
“Only later on when they’ve actually done some metallurgical test work, do they realize that it’s not quite as simple as that. And it’s difficult to talk the share price up after that. So, they tend to sell the project on to somebody else. That’s why you see some of these more difficult deposits bandied about. Because yes, the capital required for technologies like POX is not insignificant.”
E&MJ asked if we should be doing more test work early on in the scoping process to help circumvent this issue?
“Yes,” said Flatman unequivocally. “The geometallurgy must be an integral part of the whole program. You don’t have to wait until the definitive feasibility study — the last stage of the project — to start doing the metallurgical and pilot test work, which we quite often see. At that stage you’re almost too far down the line in terms of environmental permitting. For instance, if it comes up that you need higher cyanide additions, then that could affect your environmental permitting and put the project back again. That’s why it’s important.”
“The biggest issue when you’ve got a highly variable orebody is the testing requirements for various ore zones. It makes the whole process of developing the project so much more complex.
“It’s not as simple as selecting a sample and then doing work on it. Often the mining model is developed over time, so you’re always changing the blend that’s going into the plant. If you’ve got a uniform orebody it doesn’t matter that much. But when you get variability it becomes difficult. It means that you’ve tested one zone, but suddenly you’re not going to treat that on its own, you’re going to mix it with something else and you have to do another test program on that.
“Often some of the tests are done at one laboratory and the next set of tests at another and in between the origins of the samples get lost or diluted or there’s different test procedures. Most companies do a lot of test work, but often the management or the planning around that is not coherent over the whole development of the project and management of the data isn’t always that good.
“Again, that’s where modeling programs are coming to the fore; where you can have a set of standard tests on the different ore zones and the software can then integrate that into an overall model based on your feed parameters.”
“Getting back to the point about cost overruns; we’ve certainly seen underperformance on some projects because there was never a proper understanding of the orebody.”
Read the whole article here:
https://www.e-mj.com/features/refining-gold-processing/
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