Pre-concentration opportunities are available for most operations to improve the grade of their mill feed and eliminate fine/soft contaminants or coarse/hard material.
For a greenfield project, pre-concentration is difficult to evaluate due to a lack of standardized testing methods and sample top-size constraints. This is exacerbated by our current testing practices where sample preparation involves stage-crushing down to a manageable size-destroying the opportunity to evaluate coarse beneficiation methods. This paper covers recent progress by the authors to develop a standardized ranking test using half drill core samples. The objective is to consider pre-concentration at an early study stage and quantify the impact on project economics.
The laboratory test can be done on 10kg to 50kg of half core samples, measuring the metal deportment by size at different levels of impact breakage, comparable to primary/secondary stage crushing. By incorporating this test protocol with an established comminution test, it can be inserted into current metallurgical testwork programs with minimal disruption. As well as estimating the grade by size response to crushing and screening, coarse particles are tested for sensor response; at this time, typically dual-energy XRT. SRK Consulting is collaborating with Base Metallurgical Labs in Kamloops BC to provide an independent evaluation of pre-concentration at the laboratory scale before committing to the cost and sample mass requirements of manufacturer's performance tests.
