A risk-based approach using process flow diagrams for operational waste rock classification — case studies

Abstract

Acid and metalliferous drainage (AMD) management plans are generally developed as part of a site's closure plan to inhibit or mitigate the generation and release of AMD for sites with problematic materials. They are typically constructed around a body of knowledge involving multiple geoscience and environmental disciplines. However, despite the volume and degree of scientific investigations completed, if the waste rock classification system and therefore AMD management plan developed is not practical and does not take into consideration other site drivers such as production, its successful implementation and adoption is unlikely. A common weakness of AMD plans developed based on industry best practice is that they often fail the practicality test, as the characterisation process produces ambiguous outcomes such as the classification of material as uncertain with respect to acid generating potential. At the Escarpment Coal Mine, West Coast, New Zealand, a new process flow method for geochemical classification is being trialled. Results indicate that classification by a process flow method results in far fewer samples being classified as uncertain compared to the current resource consent matrix-style classification. Results presented in this paper indicate that ABA data and field column leach trials validate this approach. https://papers.acg.uwa.edu.au/p/1608_48_Pearce/ A risk-based approach using process flow diagrams for operational waste rock S Pearce et al. classificationcase studies 650 Mine Closure 2016, Perth, Australia

Progressive rehabilitation — Martabe Gold Mine as a case study

“…The geochemical classification system is described in detail in Pearce (2015) and summarised in Table 3. Predicted AMD risk is based on conventional NAPP criteria.…”