The closure and abandonment of mining areas is rarely caused by complete consumption or extraction of a resource but rather is typically associated with diminishing financial returns based on metal values, or social, political, and environmental restrictions that lead to an uneconomic scenario for a resource unit. With regard to legacy mine sites, the removal and concentration of metals is a logical step in improving environmental water quality and in producing saleable products that can assist in offsetting water treatment costs.
Each mine site requires a site-specific evaluation to determine the potential for recovering metals and to identify suitable technologies. In assessing a mining project 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 the processing of mine water to recover metals and valuable salts;
- Recovery of new value from mining facilities such as mine sludge processed to recover ferric oxyhydroxides as a source of iron, pigments and trace metals; and
- Development of 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, the development of 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.
SRK has been involved in developing new technologies, the transfer of existing technologies to new applications, and in assessing abandoned or closing mines and mine waste at existing operations with the challenge of recovering value. These projects are typically multi-disciplined and often are developed to fit in the scope and operations of existing mining or closure activities. Successfully developing them has a number of benefits: removing or isolating potential pollutants from waste, recovering value that otherwise would be lost, generating revenue, and/or off-setting closure and reclamation costs. Each operation is unique and requires a unique approach and SRK has experience in doing exactly this.
