This clock representation shows some of the major units of geological time and definitive events of Earth history. The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4. Other subdivisions reflect the evolution of life; the Archean and Proterozoic are both eons, the Palaeozoic, Mesozoic and Cenozoic are eras of the Phanerozoic eon.
The two million year Quaternary period, the time of recognizable humans, is too small to be visible at this scale. Application for reconnaissance permit, prospecting licence or mining lease for major minerals shall be submitted in relevant forms as prescribed in the Mineral Concession Rules, to the Deputy Commissioner of the concerned district. On receipt of the application and enquiry report from the Deputy Commissioner, the Directorate of Mineral Resources will scrutinize and examine the technical aspects of each case and then forward it along with comments, if any, to the Department of Mining and Geology.
It is the negative logarithm of hydrogen ion concentration and it gives a measure of acidic or basic nature of waterbodies in general or any solvent or solution in question. Huge limestone deposits often results in the development of intricate and beautiful cave systems which in turn results in the development of these caves as Geo-tourism spots.
In Meghalaya, there are a number of such geo-tourism spots like Syndai cave, Krem Lymput cave, Siju cave and many more. Gemstones are not just used in jewelry. Diamonds are used to cut and polish other materials, such as glass and metals, because they are so hard.
The mineral corundum, of which ruby and sapphire are varieties, is used in products such as sandpaper. Minerals are used in much less obvious places. The mineral gypsum is used for the sheetrock in homes. Window glass is made from sand, which is mostly quartz. Halite is mined for rock salt. Copper is used in electrical wiring, and bauxite is the source for the aluminum used in soda cans. Skip to main content. Search for:.
Describe how metals are made from mineral ores. Summarize the ways in which gemstones are used. Identify some useful minerals.
Vocabulary gemstone ore ore deposit placer reclamation Introduction Some minerals are very useful. Aluminum is made from the aluminum-bearing minerals in bauxite.
Acid drainage from a surface coal mine in Missouri. However, most gold is used to create jewelry. For thousands of years, gold ore was mined as a basis for currency , or money. Most nations stopped valuing their money on the gold standard in the twentieth century. Iron ore has been mined for thousands of years. Iron, the second-most abundant metal on Earth, is the main component of steel.
Steel is a strong, valuable building material. Metals are often associated with particular ores. Aluminum , for example, is usually found in the ore called bauxite. Aluminum found in bauxite is used in containers, cosmetics, and medicines. When miners find rock containing mineral ore, they first extract the rock from the earth.
This can be a huge process, sometimes displacing millions of tons of dirt. The rock is then crushed by powerful machinery. Metal is extracted from the crushed ore by one of two major methods: smelting or electrolysis. Smelting uses heat to separate the valuable metal from the rest of the ore. Smelting usually requires a reduction agent, or another chemical, to separate metal from its ore.
In the earliest smelters, the reduction agent was carbon in the form of charcoal. Charcoal burned with hematite ore, for instance, smelts iron. Electrolysis separates metal from ore by using acid and electricity. Aluminum, which burns at a very high temperature, is extracted from bauxite by electrolysis. Bauxite is placed in a pool of acid, and an electrical current is run through the pool.
The electrons in the current attach to oxygen and hydrogen , the other elements in bauxite, leaving the aluminum. Earth contains a finite amount of ore.
Ore genesis, the process by which a deposit of ore is created, is estimated to take millions of years. There are three major types of ore genesis: internal processes, hydrothermal processes, and surficial processes. Ore can accumulate through geologic activity, such as when volcanoes bring ore from deep in the planet to the surface.
This is called an internal process. This is called a hydrothermal process. Rocks may contain mineralisations , which is the occurrence of valuable minerals in a large quantity. Mineralisations or mineral deposits are formed by many complex geological processes.
If a mineralisation can be mined with profit, it is called an orebody. The size and economic potential of an orebody is calculated using national or international reporting standards as mineral resource and mineral reserve. The geological processes forming orebodies are complex, concentrations of valuable minerals are rare and orebodies never share the same set of characteristics. Trying to find ore is called mineral exploration , or just exploration.
Exploration is done in many steps, and it often takes several years or even decades to find and define an ore body that can be potentially mined. Few exploration projects lead to opening of a mine. Exploration means looking for mineral deposits that are commercially exploitable. Exploration usually starts in the office by studying all literature and data that is available for of an area of interest.
Field work is then conducted by mapping the surface, studying the properties of the soils and rocks with geophysical methods, and looking for elevated metal contents anomalies in soils, water or rocks.
If the area is deemed interesting enough for further investment, exploration drilling can be commenced to examine and sample soil and rock cores.
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