Mining Introduction to Mining
Mining’s Contribution to Civilization.
Mining may well have been the second of humankind’s earliest endeavors granted that agriculture was the first. The two industries ranked together as the primary or basic industries of early civilization. Little has changed in the importance of these industries since the beginning of civilization. If we consider fishing and lumbering as part of agriculture and oil and gas production as part of mining, then agriculture and mining continue to supply all the basic resources used by modern civilization.
From prehistoric times to the present, mining has played an important part in human existence (Madigan, 1981).
The term Mining is used in its broadest context as encompassing the extraction of any naturally occurring mineral substances – solid, liquid, and gas from the earth or other heavenly bodies for utilitarian purposes.
The history of mining is fascinating. It parallels the history of civilization, with many important cultural eras associated with and identified by various minerals or their derivatives:
- The Stone Age (prior to 4000 B.C.E).
- The Bronze Age (4000 to 5000 B.C.E).
- The Iron Age (1500 B.C.E to 1780 C.E).
- The Steel Age(1780 to 1945)
- The Nuclear Age (1945 to the present).
As one of humanity’s earliest endeavors and certainly one of its first organized industries, mining has an ancient and venerable history (Gregory, 1980). To understand modern mining practices, it is useful to trace the evolution of mining technology. Which has paralleled human evolution and the advance of civilization.
Mining in its simplest form began with Paleolithic humans some 450,000 years ago, evidenced by the flint implements that have been found with the bones of early humans from the Old Stone Age (Lewis and Clark, 1964). Our ancestors extracted pieces from loose masses of flint or from easily accessed outcrops and, using crude methods of chipping the flint, shaped them into tools and weapons. By the New Stone Age, humans had progressed to underground mining in systematic openings 2 to 3 ft. (0.6 to 0.9m) in height and more than 30 ft. (9m) in depth (Stoces, 1954). However, the oldest known underground mine, a hematite mine at Bomu Ridge, Swaziland (Gregory,1980 ), is from the Old Stone Age and is believed to be about 40,000 years old. Early miners employed crude methods of ground control, ventilation, haulage, hoisting, lighting, and rock breakage. Nonetheless, mines attained depths of 800 ft. (250m) by early Egyptian times.
Metallic minerals also attracted the attention of prehistoric humans. Initially, metals were used in their native form, probably obtained by washing river gravel in placer deposits. With the advent of the Bronze and Iron Ages, however, humans discovered smelting and learned to reduce ores into pure metals or alloys, which greatly improved their ability to use these metals.
The first challenge for early miners was to break the ore and loosen it from the surrounding rock mass. Often, their crude tools made of bone, wood, and stone were no match for the harder rock, unless the rock contained crevices or cracks that could be opened by wedging or prying. As a result, they soon devised a revolutionary technique called fire setting, whereby they first heated the rock to expand it and then doused it with cold water to contract and break it. This was one of the first great advances in the science of rock breakage and had a greater impact than any other discovery until dynamite was invented by Alfred Nobel in 1867.
Mining technology, like that of all industries, languished during the Dark Ages. Notably, political development in 1185 improved the standing of mining and the status of miners when the bishop of Trent granted a charter to miners in his domain. It gave miners legal as well as social rights, including the right to stake mineral claims. A milestone in the history of mining, the edict has had long-term consequences that persist to this day.
The greatest impact on the need for and use of minerals, however, was provided by the Industrial Revolution at the close of the eighteenth century.
Along with the soaring demand for minerals came spectacular improvements in mining technology, especially in scientific concepts and mechanization that have continued to this day.
During the last two centuries, there has been great progress in mining technology in many different areas. Such progress is often made in an evolutionary rather than a revolutionary manner. Yet every once in a while, a revolutionary discovery comes along and changes the process of mining profoundly. During the nineteenth century, the invention of dynamite was the most important advance. In the twentieth century, the invention of continuous mining equipment, which extracts the softer minerals like coal without the use of explosives, was perhaps the most notable of these accomplishments.
The first continuous miner was tested in about 1940, with its usefulness greatly enhanced by the development of tungsten carbide inserts in 1945 by McKenna
Metals Company (now Kennametal). By 1950 the continuous miner had started to replace other coal mining methods. The era of mechanized mining had begun.
It is not possible to chronicle all of the developments that made mining what it is today.
Economics of the Mineral Industries
It has been estimated that only a fraction of 1% of the earth’s surface is underlain with mineral deposits of commercial value.
World consumption of minerals has increased to such an extent in modern times that more minerals were used in the twentieth century than were used since the beginning of history. This has occurred because we are now a society that depends on automobiles, trains, and airplanes for transportation; telephones, television, and computers for communications; fertilizers and heavy machinery for our agricultural output; industrial minerals for home building products; and coal-fired and nuclear plants for our electrical power. These human and industrial services in turn depend on the production of minerals and mineral products in great amounts.
The uniqueness of minerals as economic products accounts for the complexity of mineral economics and the business of mining (Vogel, 1985; Strauss, 1986).
Minerals are unevenly distributed and, unlike agricultural or forest products, cannot reproduce or be replaced. A mineral deposit may therefore be considered a depleting asset whose production is restricted to the area in which it occurs. These factors impose limitations on a mining company in the areas of business practices, financing, and production practices. Because its mineral assets are constantly being depleted, a mining company must discover additional reserves or acquire them by purchase to stay in the mining business.
Other peculiar features of the mineral industries are associated with operations.
Production costs tend to increase with depth and declining grade. Thus, low-cost operations are mined first, followed by the harder-to-mine deposits.
In addition, commodity prices are subject to market price swings in response to supply and demand, which can make the financial risk of a long-term minerals project quite risky. A change in mining or processing technology can also drastically alter the economic landscape. The pattern of usage, in terms of intensity of use (lb. /capita or kg/capita) and total consumption of metals on the world market for the nonferrous metals, shows that the intensity of usage of many of these metals continues to go down while overall consumption goes up
(Crowson, 1998). Any swing in the intensity of use due to substitution or recycling can greatly affect the market price of a metal. Mining companies must therefore keep their prices low through further improvements in productivity, or market price drops can easily create great economic hardships.
Some minerals, such as precious metals, iron, and most of the base metals, can be recycled economically, thereby affecting the markets for freshly mined metals. This is good practice and favorable for the future of humankind, but it can create economic problems if the market price is adversely affected.
Substitutes for a particular mineral may be developed, particularly if the price of the mineral remains high. For example, aluminum and plastics have often been substituted for copper, and plastics have been substituted for a variety of other metals as well as for glass.
At times in recent history, certain minerals have been exceptions to economic laws because their prices have been fixed by government decree or cartels.
Official prices of gold, silver, and uranium have been regulated by government action, although they now fluctuate in free world markets. Cartels controlling industrial diamonds, oil, mercury, and tin have strongly influenced their market prices during certain time periods. However, many of these cartels have weakened or collapsed because of competition from new suppliers.
There are many terms and expressions unique to mining that characterize the field and identify the user of such terms as a ‘‘mining person.’’
The following three terms are closely related:
Mine: an excavation made in the earth to extract minerals.
Mining: the activity, occupation, and industry concerned with the extraction of minerals.
Mining engineering: the practice of applying engineering principles to the development, planning, operation, closure, and reclamation of mines.
Some terms distinguish various types of mined minerals. Geologically, one can distinguish the following mineral categories:
Mineral: a naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal form, and physical properties.
Rock: any naturally formed aggregate of one or more types of mineral particles.
Economic differences in the nature of mineral deposits is evident in the following terms:
Ore: a mineral deposit that has sufficient utility and value to be mined at a profit.
Gangue: the valueless mineral particles within an ore deposit that must be discarded.
Waste: the material associated with an ore deposit that must be mined to get at the ore and must then be discarded. Gangue is a particular type of waste.
A further subdivision of the types of minerals mined by humankind is also common. These terms are often used in the industry to differentiate between fuels, metals, and nonmetallic minerals. The following are the most common terms used in this differentiation:
Metallic ores: those ores of the ferrous metals (iron, manganese, molybdenum, and tungsten), the base metals (copper, lead, zinc, and tin), the precious metals (gold, silver, the platinum group metals), and the radioactive minerals (uranium, thorium, and radium).
Nonmetallic minerals (also known as industrial minerals): the nonfuel mineral ores that are not associated with the production of metals. These include phosphate, potash, halite, trona, sand, gravel, limestone, sulfur, and many others.
Fossil fuels (also known as mineral fuels): the organic mineral substances that can be utilized as fuels, such as coal, petroleum, natural gas, coalbed methane, Gilsonite, and tar sands.
Mining is never properly done in isolation, nor is it an entity in itself. It is preceded by geologic investigations that locate the deposit and economic analyses that prove it financially feasible. Following extraction of the fuel, industrial mineral, or metallic ore, the run-of-mine material is generally cleaned or concentrated. This preparation or beneficiation of the mineral into a higher-quality product is termed mineral processing. The mineral products so produced may then undergo further concentration, refinement, or fabrication during conversion, smelting, or refining to provide consumer products. The end step in converting a mineral material into a useful product is marketing. Quite frequently, excavation in the earth is employed for purposes other than mining. These include civil and military works in which the object is to produce a stable opening of the desired size, orientation, and permanence.
Examples are vehicular, water, and sewer tunnels, plus underground storage facilities, waste disposal areas, and military installations. Many of these excavations are produced by means of standard mining technology. Professionally, the fields of endeavor associated with the mineral industries are linked to the phase or stage in which an activity occurs. Locating and exploring a mineral deposit fall in the general province of geology and the earth sciences.
Mining engineering, already defined, encompasses the proving (with the geologist), planning, developing, and exploiting of a mineral deposit. The mining engineer may also be involved with the closure and reclamation of the mine property, although he or she may share those duties with those in the environmental fields. The fields of processing, refining, and fabricating are assigned to metallurgy, although there is often some overlap in the mineral processing area with mining engineering.