John Meech

Abstract:

Old tailings dams and dumps are receiving increased attention by industry and governments because of the need to remediate legacy sites that are significant liabilities. The opportunity to retreat old tailings dams to generate a valuable product can significantly offset the costs of remediation. Re-processing of old tailings dams can often generate positive cash flows while at the same time improving long-term liabilities. A spreadsheet model has been developed to assess environmental and social benefits that derive from retreatment, together with potential economic positives. The system simulates human decision-making about these matters using fuzzy logic and fuzzy-neural equations in which data can be input as measured numbers or as linguistic terms of relative magnitude. There are four modules in the system: Economic and Design Module; Disposal and Reclamation Module; Risk Assessment Module; and a Decision-Making Module. The system can conceptually design all process activities from re-mining through to reclamation; perform a balanced evaluation of the economic, environmental and social benefits; and assist in multi-criteria decision-making. Four hypothetical cases are described to validate and verify the model.