https://orcid.org/0000-0002-0638-3693
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ABSTRACT
When developing a process flowsheet, the risks in achieving positive financial outcomes are minimised by ensuring representative metallurgical samples and quality testwork. A case study is presented based on an underground gold operation, where poor metallurgical sampling led to grade and recovery underperformance. Sampling-related issues included: poor liaison between geologists and metallurgists; poor domaining; too few metallurgical samples collected and tested; unrepresentative sample composites and sub-samples; poor laboratory practice; and a lack of documentation and QAQC. These issues led to disruption over four years and are estimated to have cost around US$115M in lost revenue and US$7.5M in corrective expenditure. After an initial characterisation programme, a variability mini-bulk sampling and testwork phase was undertaken. This was followed by a pilot programme, progressing to trial mining and production. The paper emphasises the need for fit for purpose metallurgical sampling and testwork, and the early application of variability sampling.
Acknowledgements
The authors acknowledge OCX Asset Management SA and OCX Gold SA for permission to publish this case study. SCD acknowledges discussions with the late Dr Allan Royle; and Professors Hylke Glass and Kim Esbensen on many aspects of sampling and TOS. The analysis and opinions expressed in this paper are those of the authors and not necessarily those of their given affiliations or the mine operator.
Disclosure statement
No potential conflict of interest was reported by the authors.
ORCID
Simon C. Dominy http://orcid.org/0000-0002-0638-3693
Louisa O’Connor http://orcid.org/0000-0001-8184-3461
Saranchimeg Purevgerel http://orcid.org/0000-0003-0625-9518