WHY ARE ORES OF METALS WHERE THEY ARE? Because Mother Nature created them there, delivering selectively more metals to some settings than what is the geochemical average of metals in the Earth´s crust. Certain rock associations permit the presence of ores of certain metals-this is studied by the science of metallogeny that can establish suitability of an area for possible ore presence. This is the first step in modern mineral exploration. When metal anomaly is detected, it is sampled and when promising, drilled. Less than one drilled site in one hundred ever becomes a mine, an economic ore-producing facility. The mined ore is then treated and concentrate refined.
MINERALS-RICH REGIONS are called mineral belts or mineral provinces, and many “specialise” in certain metal, making their country a significant producer. So, Western Australia and Victoria “specialise” on gold, Mount Isa has Cu, Pb and Zn, South Australia copper and uranium. Exceptionally large deposits are called “giant” (or “world-class”) deposits. Single deposit Olympic Dam in South Australia contains around 30% of world´s uranium in ores, South African Witwatersrand basin over 40% of world´s gold.
GEOLOGICAL EXPLORATION FOR METALS and MINING. 100 years ago prospectors found ore deposits on the surface, visually or by simple techniques (e.g. panning for gold). Most easy to discover ores have by now been found, so increasingly deeper ores are now being discovered by geophysics, geochemistry, then drilled. Grades (metal contents) also rapidly decrease. Is humanity going to run out of metals in the future? Not really, as all metals are in all rocks, but in low concentrations. The extraction technology will become more sophisticated, costly and the volume of waste will grow. Better recycling will help.