The prediction of environmental risks is an important aspect of mineral resource development, supporting more effective mineral processing, better storage of waste and improving mine closure outcomes.
The Environmental Indicators (EI) project of the Australian Cooperative Research Centre for Optimising Resource Extraction (CRC ORE) focusses on designing accurate tests that yield predictive information on the characteristics of mineral resources, which may potentially impact on the environmental performance of mining operations.
The EI team is a core part of the CRC’s project portfolio. It is led by Prof Bernd Lottermoser and boasts the expertise of leading researchers at the University of Tasmania in Australia and the University of Exeter in the UK.
The EI team’s research focus has recently diversified, with key research projects in the fields of acid rock drainage (ARD) prediction, waste classification, dust characterisation, bioaccessibility testing and sensor technologies. To facilitate research in these areas, several major case study projects were completed that also encompassed the application of geometallurgical datasets for ARD prediction, and the development of an appropriate ARD testing protocol for drill core materials.
The testing protocol activities delivered field-based methods to enable ARD domaining to be performed onsite, thus allowing for waste placement decisions to be made rapidly (i.e. in under 48 hours).
A case study on the characterisation of mineral dust properties identified pathways in which predictive dust characterisation test work could be performed in drill core materials. Subsequently, a bespoke RIMS dust sampler was commissioned, which will be used in a new case study project examining drill core materials from an operational polymetallic mine.
New tests & methods
Successes for the EI team to date, have included the development of new tests and methodologies for use on mining operations.
An extensive array of new environmental indicator tests, as well as validated existing predictive tools that are commonly used in waste classification and management have been developed, in particular, a large-scale validation study was undertaken to determine the best paste pH testing method (where powdered rock and water are mixed to form a paste, the pH of which is tested) to be performed on drill core materials, from which the ASTM method was identified as the most appropriate.
The EI team developed a new computed ARD risk grade protocol utilising automated mineralogy data in a unique manner, by which surface area data of acid forming and neutralising minerals can be calculated quickly and used in ARD risk calculations. The team members based in the UK are also developing a new bioaccessibility test appropriate for drill core, allowing for the early identification of potentially deleterious elements in future waste materials to be predicted.
The microwave assisted thermal energy (MATE) pH test has been developed and patented by the team. This test is a proxy for kinetic trials, which can cost more than A$2,000 per sample for a 30 week test, and is advantageous as it is comparatively rapid, coming in around five days at the lower cost of less than $100 per sample.
To date, the EI team have published the outcomes of their case study projects and method development research programmes through a series of CRC ORE technical reports, as well as peer-reviewed journal articles and conference papers and presentations. These topics range from a review of environmental indicators used by the mining industry, to the development of new testing methodologies for waste, dust and water quality.