MBS at GEMG 2016

posted in: News | 0

MBS to attend the 2016 Goldfields Environmental Management Group Workshop in Kalgoorlie, from 18 to 20 May! Dr Michael North will be presenting a technical paper titled Using Chromium Reducible Sulfur for AMD prediction and MBS to share a booth with Outline Global. So look out for the following MBS staff, we look forward to catching up with you!

 

Kristy Profile Photo
Kristy Sell
Mike N Profile Photo
Michael North
Elizabeth Mason
Freea Profile Photo
Freea Itzstein-Davey
Talia Profile Photo
Talia Warda

Paper Abstract

Using Chromium Reducible Sulfur for AMD prediction

  • David Allen, Michael North
    MBS Environmental, 4 Cook Street, West Perth, WA, 6005
  • Silvia Black, Barry Price, Neil Rothnie
    ChemCentre, Resources and Chemistry Precinct, Manning Road Bentley, WA, 6102
  • CRC CARE Project, ATC Building, University of Newcastle, Callaghan NSW

The potential for acid and metalliferous drainage (AMD) from waste rock and tailings in hard rock mining is a key issue requiringattention all stages of mining, from the Mining Approval  to Mine Closure .  DMP are currently as part of an overall review of Mining Proposal guidelines drafting changes to the guidelines for waste characterisation.  In the past waste characterisation in Western Australia has generally been undertaken using standard static and kinetic testing methodologies specified in Australian Minerals Industry Research Association (AMIRA) (2002), the Global Acid Rock Drainage (GARD) Guide (INAP 2009) and the Commonwealth Department of Industry, Tourism and Resources (DITR 2007).  However in recent years, some companies have used different analytical methods focused on a single test, chromium reducible sulfur (CRS), rather than multiple tests.  The main driver for this being reduction in analytical costs and time savings. .

MBS Environmental participated with the ChemCentre as part of a Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE) funded project to determine whether the CRS method could be reliably used for waste rock characterisation for hard rock samples from Western Australia.  The CRS method was originally developed for use in coal mine and acid sulfate soils studies, but has recently been used in various assessments of AMD potential from hard rock mine waste in WA, despite limited validation data.  This paper outlines the results of a comparative laboratory study of 54 mine waste samples (from gold, iron ore, copper, nickel and lead/zinc mines) and pure mineral specimens from WA for AMD potential.  Key findings are:

  • CRS appears generally suitable for application in many instances – especially for common iron sulfides at low to moderate concentrations. Examples include iron ore, mineral sands and gold mining operations.  This means there are opportunities to use this method to reduce analytical costs and time.
  • Caution and a full knowledge of the properties of minerals present must be applied for high concentrations of iron sulfides or sulfides other than iron (especially lead, zinc, copper and nickel sulfides).
  • Arsenopyrite, which is often present in various mine wastes as an accessory sulfide, did not give a result by the CRS method, but did produce acid when oxidised in the laboratory.
  • There was evidence for substantial inter-laboratory bias (and intra-laboratory variation) in CRS results from commercial laboratories in WA. This raises concerns about its use alone to predict AMD.
  • Unlike most other test methods, there appears to be no available standard reference material for CRS analysis by laboratories to limit bias or errors. Inter-laboratory trials for low level acid sulfate soils are not considered appropriate for hard rock mine samples.

The results suggest that care needs to be taken when commissioning waste characterisation studies to make sure the analytical methods are appropriate for the project and that potential cost and time savings do not jeopardise the technical validity of the data being used for mine waste management planning.