Technical Talk
Pre-concentration: Case Studies in Testing
THURSDAY, DECEMBER 04, 2025, 08:35 AM - 9:05 AM PST
Increasingly, mining companies are considering pre-concentration through bulk sorting, particle sorting and even simply screening methods. However, the methods available to them are generally through vendors with specialised experience using their respective sensors and equipment. Testing is generally done to evaluate the performance of equipment rather than characterise the material and its potential for upgrading and/or waste rejection.
For some time, SRK Consulting has been working with early-stage projects and operating mines to evaluate the economics of pre-concentration. When the opportunities through grade heterogeneity show clear benefit, we proceed to the testing phase. The SRK test protocol involves coarse particle characterisation in terms of hardness, preferential breakage by metal and sensor response. (The main focus currently is x-ray transmissive sensor using the lab unit at Base Metallurgical Labs.) The results of this testing can be used to simulate a range of pre-concentration circuit options – including use in a dynamic simulator.
This paper will focus on a number of recent case studies and the outcomes of each project. Samples tested include ½ drillcore samples, coarse particles from marginal and low-grade stockpiles and SAG mill pebbles. SRK advocates testing a larger number of small mass samples to quantify differences in response before proceeding to larger mass, performance testing offered by equipment suppliers. SRK’s methodology was designed to eliminate reasons for not considering pre-concentration at an early stage with minimal disruption to the current workflow.
