Geochemical characterisation is done based upon the geology and metallurgical batch testing prior to commencement of the operation of the plant._x000D_
Tailings repository design is based upon geochemical assessment of the waste material, as well as the geomechanical issues associated with storing the waste._x000D_
The resultant conceptual and detailed design is incorporated into the environmental impact statement (EIS), upon which mine approval is based. The entire environmental monitoring and harm mitigation program, which is usually a condition of the Mine Lease approval, is based upon the applicability of the original characterisation._x000D_
Tacit to this process is that there is no change in the geochemistry of the tailings, i.e. no change in the implications for acid & metalliferous or saline/neutral mine drainage (AMD/SNMD) generation. But any changes in milling and processing can have a substantive impact on the geochemical behaviour of the tailings metallurgy, and potentially render an operation non-compliant within the conditions of the mine license._x000D_
Environmental and statutory approval implications for continuous improvements of metallurgy need to be understood because unintended consequences could cost more than the benefits of the improvement, and in some cases cost more than all the profit made from the mine. Examples uncovered during audit and consultant practice will be presented together with a process to ensure implications for adverse environmental harm and license conditions are fully considered._x000D_
*This paper is only available for individual download. It is not included in the conference proceedings* CITATION:Mulvey, P, 2013. Continuous improvement - how changes in metallurgy can have a substantive impact on environmental impact and closure - lessons learnt from environmental auditing, presented to MetPlant 2013 Conference (The Australasian Institute of Mining and Metallurgy: Melbourne).