This week’s 30 Seconds of Info is about Reconciliation and heap leach mining

This week’s 30 Seconds of Info is from Ian Glacken our Director of Geology.

Reconciliation and heap leach mining:

For all of its apparent simplicity as an extraction method, heap leaches (progressive extraction of metal from dumped – and perhaps crushed – material through chemical dissolution of valuable components) can cause real problems for reconciliation.  The simple and obvious reason for this is that the metal is not extracted immediately, but over a period of time, often spanning 3, 6, 9 or more reconciliation cycles, while the partially-extracted metal appears on the plant side of the metallurgical balance as saleable product.  During this time the physical appearance of the leach pad has not changed, and it still contains an (essentially unknown) quantity of in situ metal.  So how can we deal with this?  It’s difficult, but working from a ‘model’ or ‘theoretical’ leach depletion curve against time, hopefully based upon bench-scale or larger testing, can give us some idea of the remaining metal.  Sampling of the heap material over time as it is being leached may help, but this then raises issues with the representivity and scale of the required sampling to achieve required levels of precision.

Ian Glacken – Director of Geology
BSc (Hons) (Geology), MSc(Mining Geology), DIC, MSc(Geostatistics), Grad Dip Computing, FAusIMM(CP), FAIG, MIMMM, CEng

Ian is a geologist with postgraduate qualifications in geostatistics, mining geology and computing who has more than 35 years’ worldwide experience in the mining industry.

Ian’s skills are in resource evaluation and due diligence reviews, public reporting, training and mentoring, quantitative risk assessment, strategic advice, geostatistics, reconciliation, project management, statutory and competent persons’ reporting and mining geology studies.

Ian has a strong mining production background and is a regular auditor for the world’s largest mining companies.


If you’d like to learn more about Reconciliation, Ian presents a 1-day Reconciliation course.
Here is a LINK to the course details.

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