Most of the natural phenomena we study are variable both in space and time. Considering a topographic surface or a groundwater contamination one can observe high variability within small distances. The variability is a result of natural processes, thus deterministic. As most of these processes are sensitive and the conditions under which the they took place are not fully known, it is not possible to describe them based on physical and chemical laws completely. <...>

A large economic mineral deposit, e.g. 200 Mt underlying an area of 2 km2, is minute in comparison with the Earth’s crust and in most countries the easily found deposits cropping out at the surface have nearly all been found. The deposits for which we now search are largely concealed by weathered and leached outcrops, drift, soil, or some other cover, and sophisticated exploration methods are required to find them. The target material is referred to as a mineral deposit, unless we use a more specific term such as coal, gas, oil, or water. Mineral deposits contain mineral resources. What sort of mineral deposit should we seek? To answer this question it is necessary to have some understanding of mineral economics. <...>

Almost every human endeavor is influenced by minerals. Many natural resources used in the manufacture of goods on which civilization and our lives depend begin as minerals in the ground. The crops that we eat are grown in soil composed of minerals. The safety and stability of structures such as buildings, roads, and bridges depend on the mechanical properties of the minerals that make up the rocks and soil on which they are built. In addition, the chemical composition, structure, and texture of the minerals that compose the rocks beneath our feet provide myriad clues that guide geoscientists as they attempt to decipher the history of the earth.