Rousseau, PDS 2010, 'Providing context to acid metalliferous drainage assessments', in R Jewell & AB Fourie (eds), Mine Waste 2010: Proceedings of the First International Seminar on the Reduction of Risk in the Management of Tailings and Mine Waste, Australian Centre for Geomechanics, Perth, pp. 333-344, https://doi.org/10.36487/ACG_rep/1008_29_Rousseau
(https://papers.acg.uwa.edu.au/p/1008_29_Rousseau/)
Abstract: The why, what, how, when, where and whom questions with respect to completing an acid metalliferous 
drainage (AMD) assessment are outlined in this discussion. 
Why? AMD has been recognised as the most significant potential long-term liability associated with mining, 
particularly post closure. The requirement to understand AMD is thus driven by corporate governance, 
financing and regulatory considerations. 
What? The current definition (GARD Guide, 2009; and other guideline documents) of what an AMD 
assessment should include is broad. It includes acidity that is released through sulphide oxidation, but also 
covers release of other elements that are mobile under acidic, neutral, or alkaline conditions, as well as 
introduced contaminants. The purpose of these assessments is thus to identify all mining-related sources of 
potential contamination. 
How? To achieve a realistic AMD assessment, specialist knowledge about geochemistry, hydrogeology, 
engineering and management details of a project is necessary to evaluate AMD risk, to model systems in 
question, and to develop mitigation strategies. To evaluate the potential for impacts it is necessary that 
contaminant sources, transport pathways and receptors be identified and that their physical and 
geochemical properties must be adequately quantified. These properties must also be related to the mining 
operation using a suitable site conceptual model. 
When? AMD assessment should commence at the exploration stage, once sufficient geological information 
and sample material is available to obtain a realistic view of ore and waste geochemistry. The earlier the 
evaluation starts, the sooner AMD related liabilities and technical challenges associated with geochemistry 
for a mining project become known. 
Where? The AMD assessment should consider all materials to be disturbed by mining that could potentially 
result in significant geochemical changes and associated mobilisation of acidity or other potentially harmful 
substances. 
Whom? An AMD assessment should be carried out by technical specialists, suitably knowledgeable about 
geochemical and hydrogeological processes. Sufficient geological background is required to conceptualise 
relevant geological factors associated with a mining operation. It is also necessary for geological, mining 
and engineering personnel associated with a project to provide input to these assessments, as their 
information and activities can have a major influence on AMD related outcomes associated with material 
management.