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Surface Mining Methods
Underground Mining Methods
Under certain circumstances surface mining can become prohibitively expensive and underground mining may be considered. A major factor in the decision to operate by underground mining rather than surface mining is the strip ratio, or the number of units of waste material in a surface mine that must be removed in order to extract one unit of ore. Once this ratio becomes large, surface mining is no longer attractive. The objective of underground mining is to extract the ore below the surface of the earth safely, economically, and with as little waste as possible. The entry from the surface to an underground mine may be through an adit, or horizontal tunnel, a shaft (see shaft sinking), or vertical tunnel, or a declined shaft. A typical underground mine has a number of roughly horizontal levels at various depths below the surface, and these spread out from the access to the surface. Ore is mined in stopes, or rooms. Material left in place to support the ceiling is called a pillar and can sometimes be recovered afterward. A vertical internal connection between two levels of a mine is called a winze if it was made by driving downward and a raise if it was made by driving upward.
A modern underground mine is a highly mechanized operation requiring little work with pick and shovel. Rubber-tired vehicles, rail haulage, and multiple drill units are commonplace. In order to protect miners and their equipment much attention is paid to mine safety. Mine ventilation provides fresh air underground and at the same time removes noxious gases as well as dangerous dusts that might cause lung disease, e.g., silicosis. Roof support is accomplished with timber, concrete, or steel supports or, most commonly, with roof bolts, which are long steel rods used to bind the exposed roof surface to the rock behind it.
Environmental and Legal Concerns
Associated with mining are many environmental concerns. Large-scale excavation is often necessary to extract a small amount of ore. Ore extraction disrupts the topsoil and can displace local animals and plants, and sometimes native human populations. Runoff can contaminate nearby water sources with pollutants such as the mercury and sodium cyanide used in gold mining. Waste materials and smelters can cause sulfurous dust clouds that result in acid rain. Abandoned strip mines have often been used as unregulated landfills for hazardous wastes. Several pieces of legislation in the United States, the Surface Mining Control and Reclamation Act (1977) and the Comprehensive Environmental Response, Compensation, and Liability Act, or Superfund Act (1986), address these issues, but enforcement has been difficult.
Another act that affects mining in the United States is the 1872 Mining Act. This now controversial act, which was originally designed to encourage settlement of the West, allows mining companies to purchase land for $2.50 per acre. In the late 20th cent., despite many efforts at reform, the law and the $2.50 per acre price still stood, despite the fact that the ore contained in the land could be worth billions of dollars.
See R. Peele and J. A. Church, ed., Mining Engineer's Handbook (3d ed.; 2 vol., 1941); R. S. Lewis and G. B. Clark, Elements of Mining (3d ed. 1964); E. Pfleider, ed., Surface Mining (1968); G. C. Amstutz, Glossary of Mining Geology (1971); C. Gregory, A Concise History of Mining (1981); M. K. Tolba (United Nations Environment Programme), Saving Our Planet (1991); A. Warhurst, Environmental Degradation from Mining and Mineral Processing in Developing Countries (1994).
the branches of science and technology that embrace the processes of extracting minerals from the interior of the earth.
For thousands of years mining was limited to the extraction of only solid minerals (nonmetallic construction materials, ore, and so on). The extraction of petroleum began in the second half of the 19th century; that of natural gas, in the early 20th century.
The extraction of minerals is preceded by prospecting, which is necessary to determine the reserves, ore quality, and economic feasibility of exploiting a given deposit, the production capacity of a mining enterprise, and the methods of working deposits. Geophysical prospecting methods are being used more widely; geochemical and microbiological prospecting methods are in the process of further development. The results of prospecting surveys and stereogeomet-ric measurements are represented on maps, plans, sections, and charts by means of mining-surveying and geometric methods.
When sufficient mineral reserves have been discovered and the technical and economic feasibility of exploiting them has been shown, development of the deposit is begun on the basis of a preliminary plan. This is done by drilling holes or excavating a network of underground or opencut mines according to a specific plan; the necessary surface and subsurface facilities are constructed for stripping the deposit.
Industrial shaft operation specifications require a minimum of two exits from underground mines to the earth’s surface: one for the fresh air supply, and the other for exhaust air. These exits are usually the openings to the deposit and the network of interconnected workings, such as vertical or sloping mine shafts and tunnels. The depth of vertical shafts may exceed 2,000 m in some cases. The methods of sinking shafts and other mine workings depends on the nature and degree of flooding of the rock through which they are cut. To prevent collapses, mine walls are braced in proportion to the amount of rock excavated.
After the deposit has been stripped, so-called development is begun on the mineral with the purpose of preparing the deposit for the cleaning work. Upon completion of the development work, the cleaning work is begun in order to extract the mineral. The faces for performing the cleaning work are called the working faces, and the resulting workings are called excavations. The temporal and spatial procedure of the development and cleaning work, which is established for specific natural, geologic, technical, and economic conditions, is called the system of working the deposit.
The preliminary excavations and the cleaning work for the extraction of the minerals are usually performed by drilling, rock-loading, and cutting-loading machines.
The extracted mineral is delivered from the working face to the earth’s surface by means of a mine conveyor system; loads and personnel are transported along the mine shaft by a mine hoist.
All underground mines are supplied with fresh air. Stationary electric lighting is installed in the underground workings, and the workers are furnished with portable miner’s lamps. The water that accumulates in underground workings is continually removed by a drainage system. Special services monitor the regularity and safety of underground operations, and measures are taken to prevent and extinguish fires and to cope with accidents and their consequences.
Mining had its beginnings at an early stage in the development of human society. During the period of the tribal system underground mines, sometimes supported by wood, were excavated for the extraction of silicon. Stone implements and picks made from antlers were used for mining. The systematic mining of copper and tin ores and the extraction of gold and silver began in slaveowning society. Remains of ancient mines from the Bronze Age have been discovered on the territory of the USSR. Mine workings with traces of supports and ladders from the same period have survived in Central Europe. Mining existed in China, Japan, and regions of the American continent long before the Common Era.
The mastery of the production of iron became the main factor in the development of the productive forces in ancient society. The mines exploited the labor of huge numbers of slaves and convicts. Mining played an important role in the economy of ancient Rome toward the end of the Republic era and during the Empire period (first century B.C. to the third century A.D.).
Significant progress was made in mining with the development of feudal relations. In the 11th to 13th centuries extensive developments began to take place in mining in Central Europe, although rocks were still drilled by hand. Important improvements were made in mining in Europe during the 15th and 16th centuries. The use of the horse drive and the waterwheel for mine hoisting and drainage devices permitted mining operations down to a depth of 150 m. Blasting operations appeared and began to replace the firing method of demolition. Wet ore concentration was introduced, making possible the mining of relatively low-grade ores. In 1512 a charter for a wet stamp mill was granted in Saxony. Timber flooring for the movement of carts loaded with minerals was first installed during that period. The first mining schools were established, and manuals on mining appeared (On Mining and Metallurgy by G. Agricola, 1556). Steam engines, which were used first for pumping water (the Englishman T. Newcomen in 1711–12) and later for mine hoisting, found application in mining earlier than in other industries.
The changeover to the large-scale use of machinery in mining was accomplished in the period of the industrial revolution (late 18th to early 19th century). In 1815 the Englishman H. Davy invented a safe miner’s lamp. Drilling technology was improved, explosives were used more and more widely, and horse-drawn rail hauling was introduced. Steel cables for mine hoisting and hauling were first used in the 1830’s. The first efficient coal-cutting machines appeared in the mid-1850’s.
The conditions for the development of mining underwent a change once again between the late 19th and early 20th centuries because of a huge increase in the demand for minerals. The technology of sinking mine shafts developed intensively. Improved sinking, ventilating, and drainage methods allowed mining depths to be extended to 1,000 m and sometimes to 2,000 m. Highly efficient systems were created for mining coal and ore deposits. Electric drive was introduced for hoisting machinery, pumps, and ventilators, mine transportation was electrified, cutting was mechanized by means of coal-cutting machines, and pick-hammers operated by compressed air were widely adopted. Independent scientific and technical disciplines emerged that were concerned with questions related to the extraction of separate types of minerals, such as coal, ores, petroleum, and peat.
The major challenges confronting mining in the USSR are the rational use of mineral resources, significant increases in economic efficiency, and the improvement of working conditions (mining is the most difficult and dangerous area of the large-scale use of labor). Intensive searches are underway for new systems of mining deposits, more powerful mechanical equipment, the use of automation, and the construction of an extraction technology based on flow production. The mechanization of the breaking and loading of coal continues to increase; the loading of coal and rock in development workings is performed by cutting-loading and loading machines. Breaking and loading during the extraction of ore is also being mechanized. The use of automation and remote control of machines and equipment is expanding gradually. The mining industry is adopting the use of metal supports (in place of wood supports) and movable powered supports. There is a marked tendency to reduce in every possible way the disconnectedness of mining operations and to speed up excavation in a relatively limited number of faces. In view of this, high-output mines are being put into operation.
Increased mining efficiency is achieved primarily by the wider adoption of opencut deposit mining methods. With the opencut mining method, labor productivity is 7–10 times higher than that of underground mines, and the prime cost of extraction is considerably lower. Extraction by the opencut method increased sharply in the coal industry during the second half of the 1950’s. The relative proportion of quarry-extracted coal rose from 6 percent to 30 percent in the total world balance over the period from 1913 to 1968. In the USSR, 25 percent of the coal extracted in 1968 came from quarries.
In the USSR (1969) the opencut mining method accounted for 77 percent of the iron ore, 64 percent of nonferrous metal ores, 56.4 percent of the manganese, 46.6 percent of mining chemicals, and 100 percent of nonmetallic minerals and construction materials.
A great deal of progress has been made in the study of the physical properties of rocks, making it possible to arrive at the optimal solutions in the design and construction of rock-crushing machinery and tools, as well as in mineral recovery methods.
Theoretical and experimental work is continuing in various areas of mining that offer the possibility of the subterranean extraction of minerals without the use of human labor (by geotechnological methods), as well as the extraction of minerals from the ocean floor.
The extraction of liquid and gaseous minerals, which accounted for approximately 60 percent of the USSR’s fuel balance in 1969, has increased immeasurably, especially during the period from 1960 to 1970. The development of the extraction of these minerals was closely associated with the development of well-drilling technology. The exploitation of petroleum deposits is conducted at great depths in the sea by artificial action on the stratum (for example, by flooding). The gas industry of the USSR is creating efficient gas fields with annual outputs of 75–100 billion cu m and large-diameter main gas pipelines.
REFERENCESBokii, B. V. Gornoe delo, 3rd ed. Moscow, 1959.
Sheviakov, L. D. Razrabotka mestorozhdenii poleznykh iskopaemykh, 4th ed. Moscow, 1963.
Agoshkov, M. I., and G. M. Malakhov. Podzemnaia razrabotka rudnykh mestorozhdenii. Moscow, 1966.
Mel’nikov, N. V. Mineral’noe toplivo, 2nd ed. Moscow, 1971.
Rzhevskii, V. V. Tekhnoiogiia i kompleksnaia mekhanizatsiia otkrytykh gornykh rabot. Moscow, 1968.
Tekhnoiogiia podzemnoi razrabotki plastovykh mestorozhdenii poleznykh iskopaemykh. Moscow, 1969.
N. V. MEL’NIKOV
The taking of minerals from the earth, including production from surface waters and from wells. Usually the oil and gas industries are regarded as separate from the mining industry. The term mining industry commonly includes such functions as exploration, mineral separation, hydrometallurgy, electrolytic reduction, and smelting and refining, even though these are not actually mining operations. See Hydrometallurgy, Metallurgy, Ore dressing
Mining is broadly divided into three basic methods: opencast, underground, and fluid mining. Opencast mining is done either from pits or gouged-out slopes or by surface mining, which involves extraction from a series of successive parallel trenches. Dredging is a type of surface mining, with digging done from barges. Hydraulic mining uses jets of water to excavate material.
Underground mining involves extraction from beneath the surface, from depths as great as 10,000 ft (3 km), by any of several methods.
Fluid mining is extraction from natural brines, lakes, oceans, or underground waters; from solutions made by dissolving underground materials and pumping to the surface; from underground oil or gas pools; by melting underground material with hot water and pumping to the surface; or by driving material from well to well by gas drive, water drive, or combustion. Most fluid mining is done by wells. In one experimental type of well mining, insoluble material is washed loose by underground jets and the slurry is pumped to the surface. See Petroleum engineering
The activities of the mining industry begin with exploration, which, since accidental discoveries or surficially exposed deposits are no longer sufficient, has become a complicated, expensive, and highly technical task. After suitable deposits have been found and their worth proved, development, or preparation for mining, is necessary. For opencast mining, this involves stripping off overburden; and for underground mining, the sinking of shafts, driving of adits and various other underground openings, and providing for drainage and ventilation. For mining by wells, drilling must be done. For all these cases, equipment must be provided for such purposes as blasthole drilling, blasting, loading, transporting, hoisting, power transmission, pumping, ventilation, storage, or casing and connecting wells. Mines may ship their crude products directly to reduction plants, refiners, or consumers, but commonly, concentrating mills are provided to separate useful from useless (gangue) minerals.
A unique feature of mining is the circumstance that mineral deposits undergoing extraction are “wasting assets,” meaning that they are not renewable as are other natural resources. This depletability of mineral deposits requires that mining companies must periodically find new deposits and constantly improve their technology in order to stay in business. Depletion means that the supplies of any particular mineral, except those derived from oceanic brine, must be drawn from ever-lower-grade sources.
Bitcoin(1) For a comparison of the two prominent blockchain platforms, see Bitcoin vs. Ethereum.
(2) In 2009, Bitcoin was launched as a "peer-to-peer electronic cash system" by a person with the alias Satoshi Nakamoto. The first cryptocurrency, Bitcoin spawned a revolution in finance (see Web 3.0). Although merchants increasingly accept Bitcoins as payment, many people buy and hold for speculation because the current price per coin is based on market demand (see hodling). Since its inception, the value of a single coin has skyrocketed, and thousands of other cryptocurrencies have been created. For a complete list, visit www.CoinmarketCap.com or www.CryptoCompare.com. See crypto craze and Bitcoin pizza.
Three Distinct Features
Three things set Bitcoin apart from money such as the dollar or Euro. The first is its decentralized architecture, which means there is no middleman such as a bank or government agency.
Secondly, the reason Bitcoin is called a cryptocurrency is because it uses cryptography to hide the actual identity of both parties. The transaction itself is public; for example, on June 1, 2019, Bitcoin address A sent 2.5 Bitcoins to Bitcoin address B. The parties are considered pseudonymous rather than truly anonymous because, although their names are not public, their Bitcoin addresses are (see Bitcoin address).
Bitcoin's blockchain architecture also uses cryptography to tie all transactions together in such a way that if any were to be altered it would be immediately known. Thousands of volunteers are constantly validating the integrity of the chain. Once a Bitcoin transaction has been confirmed, it cannot be altered and is considered irrefutable. See blockchain and cryptographic hash function.
Lastly, there is a maximum number of Bitcoins that come into existence every year, and as of 2021, there are approximately 18 million. In the year 2140, coin creation ceases. After that, there will never be more than 21 million Bitcoins in the world, and people believe this makes Bitcoin inflation proof. Bitcoin is also called "digital gold," because gold is often said to be a hedge against inflation. See Bitcoin mining and public key cryptography.
Underground and Above Board
Although used for clandestine transactions because of its pseudonymity (ransomware now demands payment in Bitcoin), more than 2,000 legitimate businesses in the U.S. and 15,000 worldwide accept Bitcoin. In 2021, Tesla added Bitcoin to its online order form but removed it soon after claiming the crypto uses too much of the world's electricity (see Bitcoin mining). See ransomware and Dark Web.
Anyone Can Buy, Transfer and Sell Bitcoins
Users access their coins from a digital wallet in their own device or employ the services of a cryptocurrency exchange. Once an account is established, coins are bought with national currencies, and a fee is paid for every Bitcoin transaction. See Bitcoin wallet, Bitcoin exchange and Bitcoin ATM.
Like a share of stock, the value of a Bitcoin fluctuates on the crypto exchanges with huge volatility. However, even with the gigantic dip in 2018, a single coin rose from virtually nothing to more than $60,000 in 10 years, creating a market cap of more than $1 trillion. It since dropped into the $40-50,000 range. See Bitcoin pizza.
In 2017, Bitcoin split into three versions, and the original Bitcoin was enhanced for performance (see Bitcoin Cash, Bitcoin Gold and SegWit).
Bitcoins Are Mined!
The unusual thing about Bitcoins is the way they come into existence. Bitcoin "miners" compete with each other to update the blockchain with new transactions, and they are rewarded with Bitcoins created "out of the blue" for their own account. See Bitcoin mining.
Traction - Then Hacking
In late 2010, Bitcoin was becoming popular in the open source and underground communities. By mid-2011, there was an attack on the Japan-based Mt. Gox exchange, and a hacker extracted coins worth nearly $450M. See Mt. Gox.
Who Is Satoshi Nakamoto?
Nakamoto's true identity has never been disclosed. However, no matter who Satoshi Nakamoto is, in order to commemorate the developer, the smallest fraction of a Bitcoin is called a "Satoshi." See Satoshi and Satoshi Nakamoto.
Government Printing vs. Bitcoin Generation
When people argue that Bitcoins are no less valid than the U.S. dollar, there is a distinction to note. Bitcoins have nothing to back them up but the faith of the people using them. Although the same might be said of U.S. currency, the United States has the IRS and other federal agencies to ensure that people pay taxes. Nevertheless, proponents claim that Bitcoin and other blockchain-based platforms are revolutionizing all kinds of transactions worldwide. For more information, visit www.Bitcoin.org, www.Bitcoincharts.com, www.blockchain.info and http://en.Bitcoin.it. See BIP, Bitcoin transaction, Bitcoin vs. Ethereum, stablecoin, Silk Road and crypto glossary.
Nakamoto's Own Words
Perhaps nobody can describe Bitcoin better than its inventor. The following abstract appeared online on October 31, 2008, shortly before Bitcoin was launched.
Bitcoin: A Peer-to-Peer Electronic Cash System
"A purely peer-to-peer version of electronic cash would allow online payments to be sent from one party to another without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as a majority of CPU power is controlled by nodes that are not cooperating to attack the network, they'll generate the longest chain and outpace attackers. The network itself requires minimal structure. Messages are broadcast on a best effort basis, and nodes can leave and rejoin the network at will, accepting the longest proof-of-work chain as proof of what happened while they were gone." See double spending.
|Essential Reading for Enthusiasts|
|Books by Andreas Antonopoulos are incredibly thorough, and this one is no exception. If you want to know the ins and outs of Bitcoin, this is must reading.|
Bitcoin miningBitcoin mining is the process that adds new Bitcoin transactions to the distributed ledger known as the "blockchain." Mining is also how new coins come into existence as a reward for being the first miner to add the next block of transactions to the blockchain.
Like a gold mine, which takes work and time to produce results, Bitcoin mining requires "digital work" and "processing time" to bring coins into creation. Hence the "mining" metaphor. However, this processing time uses an enormous amount of electricity worldwide (see cryptographic hash function). See blockchain.
While there are tens of thousands of nodes in the Bitcoin network that verify transactions, a smaller number are mining nodes. New transactions reside in the Bitcoin memory pool (mempool) until a miner retrieves them, verifies the integrity of their format and is the first to complete a mathematical puzzle, which takes about 10 minutes. The winning miner places the transactions in a block and adds them to the blockchain. Each new block provides more confirmation of the previous transactions (see Bitcoin confirmation).
Miners Are Rewarded with Bitcoins
The mathematical puzzle takes a gigantic amount of calculations to solve and ensures that miners spend time and resources, thus providing "proof-of-work" (PoW). The first miner to solve the puzzle and publish the block to the blockchain is rewarded with fees and new Bitcoins (see block reward). If two miners solve the puzzle at the exact same time, the miner that did the most computational work is the winner. The massive digital processing required also keeps fraudulent miners away. See proof-of-work algorithm.
Years ago, anyone with a PC could be a miner. However, the Bitcoin algorithm was designed to be more difficult as time passes. Today, it could take a regular PC so long to solve the puzzle that it would never be first to do so. However, PCs can still be used for other cryptos (see pool mining).
Chinese Mining Pools
Organizations create huge mining pools to accomplish the task using specialized "ASIC miner" hardware. Located in China where electricity is less expensive, pools mine roughly 65% of Bitcoin transactions worldwide. In 2021, China started to crack down on Bitcoin trading and mining, and China-based miners are packing up and moving to Central Asia and North America. See miner hardware and cryptographic hash function.
The Maximum Number of Bitcoins Is 21 Million
The Bitcoin algorithm ensures that the number of new coins miners generate for their own accounts slows down over time. At some point in 2140, the total number of coins will be capped at 21 million. Starting with 50 coins in 2009, by 2013, there were 10.6M Bitcoins in existence, and by 2020 roughly 17M. The first four years generated 10 million coins, but the subsequent five years only six million more. After 2140, the only revenue miners will receive is from transaction fees. See block reward.
The Cap Is a Major Feature
Bitcoin proponents claim that the capped total of coins is what makes Bitcoin valid money, similar to having physical gold bars. Just like an ounce of gold, the market may change its daily value, but a devaluation cannot occur due to inflating the money supply. See Bitcoin, cryptojacking and crypto glossary.
|CleanSpark Bitcoin Miner|
|Headquartered in Henderson, Nevada, CleanSpark is a renewable energy company that features residential and commercial solar systems. It also uses its facilities to mine Bitcoin in New York state and Georgia. (Images courtesy of CleanSpark.)|
crypto mining(CRYPTOcurrency mining) The competitive process that verifies and adds new transactions to the blockchain for a cryptocurrency that uses the proof-of-work (PoW) method. The miner that wins the competition is rewarded with some amount of the currency and/or transaction fees. Following are the ways mining is performed. See proof-of-work algorithm.
Anyone can purchase specialized miner hardware and connect to the Internet. This was more feasible in the early 2010s than it is today. However, new currencies come online all the time, and if they employ the proof-of-work (PoW) method rather than proof-of-stake (PoS), regular computers or computers with high-end GPUs may be sufficient for mining. See miner hardware and GPU.
Organizations combine their resources to obtain a huge amount of mining hardware. Mining pools are also open to the public, whereby anyone can add their computers to the network.See pool mining.
People can rent time on a cloud mining service and pay a monthly fee. See cloud mining.
The puzzle that miners attempt to solve for Bitcoin and Ethereum, the two major cryptos, consumes a lot of electricity. Known as the "proof-of-work" consensus algorithm, the Digiconomist website (www.digiconomist.net) says Bitcoin and Ethereum together consume as much energy as Indonesia. However, Ethereum is changing its consensus method, which began in late 2020 (see Ethereum 2.0). Contrast with crypto minting. See consensus mechanism, blockchain, Bitcoin mining and cryptojacking.
|Everything About Mining|
|Peter Kent and Tyler Bain explore crypto mining in depth. For anyone who wants to know the ins and outs of this complicated business, their book is must reading.|
data miningExploring and analyzing detailed business transactions. It implies "digging through tons of data" to uncover patterns and relationships contained within the business activity and history. Data mining can be done manually by slicing and dicing the data until a pattern becomes obvious. Or, it can be done with programs that analyze the data automatically. Data mining has become an important part of customer relationship management (CRM). In order to better understand customer behavior and preferences, businesses use data mining to wade through the huge amounts of information gathered via the Web. See social media mining, data miner, Web mining, text mining, OLAP, decision support system, EIS, data warehouse and slice and dice.
|Doing It Automatically|
|This BusinessMiner analysis determined that the most influential factor common to non-profitable customers was their credit limit. (Image courtesy of SAP.)|