A common theme in evaluating mine sites, even abandoned or closed sites, is the potential for sustainable development either through mining or in a post- mining phase.
The reality is that closing and abandoning mining areas is rarely due to complete consumption of a reliable resource but rather due to diminishing financial returns based on metal or mineral values, or social, political and environmental restrictions that lead to an uneconomic scenario for a resource unit. In assessing a mining area there are several potential sources of economic value, including:
- Previously unidentified resources in the mining area.
- Mining of known in-situ ore and stockpiled unprocessed ore.
- Recovery of value from previously processed waste and previously cited “mine waste”.
- Recovery of value from undeveloped resource, such as processing mine water to recover metals and valuable salts.
- Recovery of new value from mining facilities, such as processing mine sludge to recover ferric oxyhydroxides as a source of iron, pigments and trace metals; developing energy resources from power generation using in-ground heat pumps, high geothermal gradients and/or storing excess CO2.
- Developing mine water resource for agricultural, industrial or even potable water.
In the case of the first two potential sources, unconventional or innovative methods of exploration may be required to identify these resources; additionally, developing water as a resource either for metal or salt recovery or as a source of useable water requires hydrogeochemical investigations. The successful development of these resources and value recovery often requires more efficient metallurgical circuits or new chemical and physical extraction procedures to recover value.
This paradigm shift in thinking has already taken place. High mining costs, increasingly stringent environmental regulations, and the need to reduce liabilities is encouraging the re- assessment of mine wastes as potential “new” resources. Water treatment and management technologies employed by SRK help to provide clean water for alternative use while creating by-products that could be marketable, or disposed of as a non-hazardous material, thereby reducing the cost and long-term liability of disposal. When these recycled or refined materials are found to have a market, a revenue stream is created which can offset ongoing treatment.
Furthermore, extracting resources from mine wastes and marketing these resources contributes to the long-term sustainability of the mining operation. This helps to offset closure issues and costs while allowing continued wealth generation. SRK has been involved in several such studies and continues to develop strategies to mitigate the impacts from mining operations while looking to provide more sustainable practices for mining operations and maximise shareholder value.
