Applied Geochemistry in Mineral Exploration and Mining

Abstract

T he prosperity of our societies and our standards of living are directly related to our ability to fi nd, exploit, and manage our metal and mineral resources. Metal and mineral deposits are, in fact, geochemical anomalies and, as such, applied geochemistry plays a critical role throughout the mineral resources value chain, from early stage exploration to mine closure. The fundamentals of element mobility (i.e. transport and fi xation) in the near-surface environment are used by geochemists to detect mineral deposits at depth, reveal element distributions in and around deposits, assess the total geochemical environment, and refi ne effective and benign extraction and waste disposal techniques. Both pure-and applied-research ventures play fundamental roles in providing the techniques to manage metal resources and thereby benefi t society. FIGURE 1 Average lifetime consumption of metal and mineral resources for individuals in fi rst-world countries. DATA FROM WWW.MINERALSEDUCATIONCOALITION.ORG.

Future Global Mineral Resources

“…In addition, the availability of high-accuracy Global Positioning System (GPS) data since 2000 has substantially improved the efficiency and location accuracy for regional-to local-scale geological mapping and other exploration activities. (Kyser et al, 2015) Drainage surveys are an extension of panning stream sediments used by the Ancients, old-time prospectors and present-day geologists to trace resistant ore minerals dispersed mechanically into drainages by weathering of ore. Panning to register the presence of alluvial gold or cassiterite was used traditionally to discover gold and tin sources, and is still used in modern stream-sediment surveys as an adjunct to collection and chemical analysis of fine-grained sediment fractions.…”

“…A range of other, usually proprietary, geochemical prospecting techniques, commonly with partial or selective leach techniques, have been used to search for deep mineralisation, often under thick transported recent cover, but with uncertain success. The most effective geochemical techniques are based on careful collection of sample media followed by sample preparation and analysis using continually improving analytical tools (Kyser et al, 2015).…”

“…Vegetation geochemistry, or biogeochemistry (Kyser et al, 2015), in the form of visual observation of plants occurring close to ore, may have been used as much by old-time prospectors to make discoveries as were visible signs of ore in rock and soil. Chemical analysis of plants, known as biogeochemical prospecting, was first used in 1936 to explore for tin, tungsten, lead and zinc in Cornwall and Wales, with Harry Warren pioneering the technique in Canada.…”

“…Exploration geochemistry, or geochemical prospecting (Ginzburg, 1960;Kyser et al, 2015), was developed in western countries in parallel with improvements in trace element analysis in the 1940s (Hawkes, 1957), about 15 years after analytical exploration geochemistry was first carried out on soils in the Soviet Union in 1932. Various types of geochemical survey are employed depending on the type of ore deposit target and its geological setting, using the most appropriate media -e.g., drainage (stream sediment), soil or talus, rock, vegetation and ground water -for the environment (see Appendix).…”

Laser-Induced Breakdown Spectroscopy—An Emerging Analytical Tool for Mineral Exploration

“…Cryptic geochemical footprints such as these may not be not associated with any visual indicators, but tend to be larger than any single mineralogical or geophysical pathfinder at most ore systems [19,22].The identification of geochemical footprints has the potential to greatly increase the size of the exploration target. A large variety of approaches were deployed for geochemical vectoring, such as lithogeochemistry, stable and radiogenic isotopes, indicator minerals, hyperspectral scanning, biogeochemistry, hydrochemistry, and sediment geochemistry [23,24]. Each of these approaches…”