EXPLORATION:-Mineral exploration is the bed rock of any successful exploitation or extraction of any abundant mineral in a particular or selected area for exploration and mining. In the solid mineral industries exploration has proven to help in the determination of commercially viable concentration of mineral for mining, the depth of deposition of minerals, the quality of mineral, the quantity and even the economic worth of the mineral being sought after. There are also some doubts over the success rate of each exploration done and the question has been raised whether the success rate is actually going down. At least there are indications that this is happening. This might partly be explained by the fact that exploration is getting more difficult because of several factors but there could also be a decrease in exploration efficiency.
AREA OF SELECTION FOR EXPLORATION
Area of selection is a crucial step in professional mineral explorations. Selection of best, most prospective area in a mineral field, geological region or terrain will assist in making it not only possible to find ore deposit but to find them easily, cheaply and quickly. Area selection is based on applying the theories behind ore genesis. The knowledge of known geological regions via the study of geological maps, to determine potential areas where the particular class of ore deposits being sought may exist.
This process applies the disciplines of basin modeling, structural geology, geochemistry, petrology and host of geophysical and geochemical disciplines. Most area of selection for exploration is also influenced by the commodity being sought, exploring for gold occurs in a different manner and within different rocks and areas to explore for oil or natural gas or Iron ore.
Similarly, companies of different sizes (in terms of market capitalization and financial strength) may look for different sized deposits or deposits of minimum size depending on their will and ability to finance construction. Often the major mining houses will not look for deposits of less than a certain size class because small deposits will not meet their criteria for an internal rate of return. This practice may result in larger mining companies relinquishing control of smaller ore bodies they find or may preclude them from entering a terrain which is characterized by deposits of a particular type or style.
Any area selected for mineral exploration also carries various forms of sovereign and other associated risks; that is, the risk that even if a commercially viable deposit is present, political, environmental and social factors make the discovery and development of the mineral resources enviable.
DEPTH OF DEPOSITION
This is determined by various methods, in most solid mineral industries, coring method is basically used in determining the depth of deposition of solid mineral.
The technique of coring long predates attempts to drill into the earth’s mantle by the Deep Sea Drilling Program. The value to oceanic and other geologic history of obtaining cores over wide area of sea floors soon became apparent. Core sampling by many scientific and exploratory organizations expanded rapidly. Coring is a method used in sampling surroundings of ore deposits and oil explorations.
Core sample is a cylindrical section of (usually) a naturally occurring substance. Most core samples are obtained by drilling with special drills into the substance, for example sediments or rock drill. The hole made for the core sample is called the “core hole”. Coring happens when a heated alloy, such as a Cu-Ni system, cools in non – equilibrium conditions.
This causes the exterior of the material to harden faster than the interior. Coring causes the center of the grains to retain more of the higher melting temperature element. In this case, the dendrite arms formed from the exterior have a different composition than the alloy in the inner regions, resulting in local compositional difference.