Geology Essay Example | Topics and Well Written Essays - 1250 words

Geology - Essay Example After miners have extracted the ores from the ground, they then refine them using other substances to remain with the valuable elements. Extraction and processing of these iron ores is an expensive venture but it largely depends on mineral concentration and the form it occurs in the ground. In order to establish if a mine is commercially viable, the engineers evaluate if it has substantial mineral and metal deposits whose proceeds will generate income over and above the mining costs. In mineral extraction, there are terms that help us understand this whole refining process. Industrial minerals are stones and other naturally occurring substances that are mined and processed because they have an economic value. This is because they are used to produce other compounds and objects that are used for technological advancements. Protolith is the original rock formation that is passed through a series of solutions to come up with the resultant mineral, the process of passing these rocks thro ugh water and other solutions through a chemical reaction is called metasomatism. Gangue is a term that refers to the parts of the ore left after minerals and metals have been extracted. It is the largest contributor to environmental concerns associated with mineral extraction since it forms large debris that is not easily disposed. They also contaminate water meant for commercial and domestic use when it comes into contact with. This is because it has other dangerous minerals which mix with water to form a harmful compound to animal and plant life (Middleton, 2003 p 56)2. Other gases are released to the atmosphere causing air pollution. Occurrences The earth is made up of three components; the air (atmosphere), water (hydrosphere) and land (lithosphere). Minerals form part of the soil underneath our feet. There are numerous geological reactions that happen underground that result in mineral formation and its contents largely depends on the amount of each element taking part in the process. The time taken to form these minerals also ensures huge deposits since some chemical reactions take time to reach full reaction. The time taken and amount of elements forming these minerals and metals determine the quantity and quality of eventual produce. Geologists then determine these considerations before engaging the authorities and locals in preparations for extraction. For instance, to extract commercially viable aluminium from the ground, its composition in the gangue should be at 8.2%, with an acceptable grade of 30%. It is at 5.6% and 50% for iron respectively (Mather, 1967)3. These metals exist in their mineral form in a variety of compounds shown by chemical formulas. Table 1: Mineral occurrences of famous metals Mineral Metal Mineral formula Galena Silver Ag Native gold Gold Au Azurite Malachite Chalcopyrite Copper (exists in three forms) Cu3(CO3)2(OH)2 Cu2CO3(OH)2 CuFeS2 Haematite Magnetite Pyrite Iron(exists in three forms) Fe2O3 Fe3O4 FeS2 Galena Lead PbS Ca ssiterite Tin SnO3 Cinnabar Mercury HgS Geological distribution These metals exist in the ground as sulphides, sulphites, sulphates, silicates and oxides. The choice of chemicals used in purification stage depends on the form parent metal exists in. Copper exists in three forms (Cu, Cu2 and CuO) and together with iron, are mostly found in carbonate rocks which are formed through a prolonged process of chemical reactions. These metals are also found in sandstones and shales which are sub-crustal rock formations (Press, 2004 p 71)4. Evaluating mineral deposits across the globe is an arduous task since it is difficult to effectively determine the presence of a metal in geographically expansive