In the assessment of 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 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.
• Development of mine water resource for agricultural, industrial, potable use and possibly for use as an energy source.
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 usable 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.
In this paper, the geochemical investigation of abandoned mine lands and particularly mine waste and water are described, along with methods of metal recovery derived from an understanding of the geochemistry.
