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Demand for minerals (especially from the developing world) Demand for products made from minerals. Why explore for minerals? Predicted demand for copper world wide Source: Courtesy of Queensland Government Dept Mines and Energy

Satellite photographs (remote sensing) Remote Sensing is the science and art of acquiring information without coming into physical contact with the objects. In remote sensing, information transfer is accomplished by use of electromagnetic radiation (EMR). EMR is considered to span the spectrum of wavelengths from 10 mm to cosmic rays up to 1010 mm. Energy Interactions, Spectral Reflectance and Colour Readability in Satellite Imagery All matter is composed of atoms and molecules with particular compositions. Therefore, matter will emit or absorb electro-magnetic radiation on a particular wavelength with respect to the inner state. All matter reflects, absorbs, penetrates and emits Electro-magnetic radiation in a unique way. Electro-magnetic radiation through the atmosphere to and from matters on the earth’s surface are reflected. Therefore, each mineral is highlighted on the satellite imagery at a particular wavelength (colour)

Difficult to find Deeper locations Grades of ore are lower The search begins Satellite Image

Size and quality of the deposit Geographical location Depth at which it is found Environmental impact Marketability Is it worth mining?

Satellite Imagery Magnetometers Aerial Exploration Source: Queensland Resources Council

Magnetic Surveys The orientation and strength of the earth’s magnetic field has been measured and studied in detail at many locations. A magnetic high is where the measured field strength is higher than the value predicted by the global model, and a magnetic low is where the measured field strength is lower than the value predicted by the global model. In most cases these rock masses contain the mineral magnetite. Rocks which contain lots of magnetite include gabbro, diorite, basalt and other “mafic” igneous rocks. These rocks will show up as a strong magnetic high on a map of the total field strength. Felsic igneous rocks, like granite or rhyolite, and most sedimentary rocks are notably non-magnetic except in rare cases. These rocks may show up as distinct magnetic lows.

Measure the earth's magnetic and gravitational and electrical properties Aerial Geophysical Surveys Image courtesy of Queensland Government Dept Mines and Energy

Measure: the earth’s magnetic conditions resistance to the electric current local gravitational effects Geophysicists Image courtesy of Queensland Government Dept Mines and Energy

Indicates a viable spot Maybe worth mining Can lead to aerial surveys Applies computer manipulation to maps to secure more information An anomaly

Land based exploration Source: Queensland Resources Council

Analyse the mineral content of soil, water, vegetation Provide indications on what lies beneath the surface. Geochemists Image courtesy of Queensland Government Dept Mines and Energy

Surface Drilling Source: Queensland Resources Council

Surface and Ground Water Ground water collected from wells, springs, and drill holes may provide clues to the presence of covered deposits. This water moves very slowly through the overburden until it discharges at the surface as a spring or seeps into a body of water. Subsurface flow rates vary from almost zero to over 100 feet per year. The slower rates cause water to have a longer contact time with the subsurface gravels, rocks, and, if present, ore deposits, permitting minute amounts of metals to be leached from the rocks. Detecting gold in a ground-water dispersion pattern requires an extremely sensitive analytical technique which measures gold in water at the one-part-per-trillion (ppt) determination level.

Collate and analyse information from maps, geophysical aerial surveys, satellite images and previous surveys Use information from the geological survey sections of state government mines departments, Geoscience Australia Geologists Source: Queensland Resources Council

Economic Assessment Exploratory Shaft Ore Analysis Further studies Image courtesy of CSIRO

Commercial Viability Environmental Affects Community support The final decision! Distribution of metal deposits in Queensland Image courtesy of Queensland Government Dept Mines and Energy