July 11th, 2001

FALMOUTH, United Kingdom - The 1st International Symposium on Magnetic, Electrical & Gravity Separation (MEG's 2001) conference marked the official unveiling of the latest tool in gravity circuit flowsheet development and design; Knelson's proprietary p redictive gravity modeling program, KC*ModPro. The program has been developed over the last four years at Knelson 's Research and Testing Centre (KRTC) under the supervision of Ishwinder Grewal, KRTC Manager.

A standard gravity recoverable gold (GRG) test is conducted to establish a GRG value for the ore in question. This test involves multiple stage grinding and processing with a laboratory scale Knelson Concentrator. This iterative model combines the GRG value with empirical plant data to produce a plant scale GRG recovery estimate. The model also incorporates much of the work done at McGill University to understand the behaviour of gold within grinding circuits.

The scale-up accuracy of the model from the laboratory to the plant is proving to be extremely reliable thanks to the quality of the data that has been used in the development of the program. "We can't say it's absolute, but we can say that in numerous case studies to date the prediction of the model has proven to be accurate to within 1-2% of plant recovery", commented Grewal.

"We are always looking for more operating plants interested in working with us as test cases to help us further verify accuracy; however, thus far we have been very pleased with what we have seen", he added.

The model inputs, which include variables such as gold survival in the mill, cyclone efficiency, unit recovery and tonnage treated, can be manipulated to clearly indicate the optimum circuit design and to assist in the selection of the Knelson unit required.

While not available for sale, access to KC*ModPro is available through Knels on's research & testing centre (KRTC) in Canada.