Mining is a necessary component of the world we live in and it has been practiced for thousands of years. The mining industry produces billions of tons of raw product every year. The process of mining is very complicated and involves plenty of physics! Two main components of the mine cycle are: Drilling, and Blasting. Some important factors in mining are the pillars, rock elasticity, and the slope stability of the ground being mined.
A basic method for destroying rock is mechanically induced stress, such as drills and erosion jets. A turbine drill for example, uses a turbine to rotate a diamond faced cutter wheel. The power output, p, can be calculated using the equation p=2 πNT where N is the rotational speed of the turbine and T is the torque on the cutter wheel. As the rotary speed increases, the torque decreases. The maximum power output of a turbine drill is when the rotary speed is between 5,000 and 10,000 rev/min.
Erosion jets can be classified as low speed or high speed. The low speed jets use abrasive particles, such as sand to erode rock at 10 to 200 m/s and the high speed jets use water at 200 to 1,000 m/s. The high speed jets are used for the hardest rock and require pressures up to 5,000 kg/cm²!
In underground, non coal mining, the excavation of rock is done largely by conventional percussive drills. These break the rock by indentation. The drilling machine applies a force to the drill bit, giving it a velocity which hits the rock and causes it to break. The equation for the peak stress induced by the drill bit on the rock is as follows: σ = ρ cv, where σ is the maximum stress induced, and ρ, c, and v are the density, compressional wave length, and velocity of the drill bit, respectively.
In coal mining, ...
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... Now there is an added force from the water called pore pressure and the normal force is decreased making the slope more likely to fail. The following diagram represents this scenario with 'W' as the gravitational force downward of the upper rock, 'p' as the pore pressure from the water, and 'A' as the area that the water affects.
Mines are erected by pillars, which have factors of safety. The factor of safety is the average strength divided by the average stress ratio. When this ration falls below 1.00, there is pillar instability. If one pillar in a mine collapses, the result is greater force acting on the rest which in turn increases their stress and decreases their factors of safety. If all of the pillars are highly stressed, one pillar failure could lead to a domino effect and the collapse of a mine. 1.60 is considered a good factor of safety for pillars.
The Making of a Hardrock Miner written by Stephen M. Voynick, describes his own personal experiences as a hardrock miner in four different underground mines in the western United States, the Climax molybdenum mine in Colorado, Hecla Lakeshore Project a copper mine in Arizona, and two uranium mines in Wyoming. Rather than a book telling of the fortunes gained and lost, this book was about the relationships gained, but then also lost through mining. Stephen M. Voynick’s direct words and simple writing style provided a book that was an easy read and educational about mine work and safety.
hard rock is eroded, it can cause an island of hard rock left of the
Hartman, Howard L., and Jan M. Mutmansky. "Introduction to Mining." Introduction to Mining Engineering. 2nd ed. N.p.: Wiley, 2002. 1-22. Print.
This is related to the blending of the fluids and rocks of the reservoir. Skeletal properties of interest to reservoir engineers include porosity, pore size distribution, compressibility, and absolute permeability of the rod. Interaction or dynamic properties of reservoir rocks are affected by the nature and by its interaction with present fluids, as...
and changing them with the velocities/momentum of a meteor. It attempts to simply model a meteorite or
...e shaped and given a smooth finish by rubbing rock on rock, an abrasive. For gouging and digging, artists used a drill tipped with extremely hard stone and a mounted by a rod weighted down with bags of small stones and rotated by a handle. This method required immense amounts of dexterity and patience.
In a typical year, the mining industry is responsible for almost 20 per cent of Canada's total export earnings3 (See Appendix A). As for the employment rate, over 70 per cent of the mines are owned by Canadians and approximately 108,000 Canadians are directly employed in the mining industry4. Mining is very important in Canadian life. Not only do the products power the family car and heat the family home, the manufacturing sector, the high tech industries and even the better known resource industries are all dependent, in some way, on the mining industry. The mining industry will continue to be an important support to the economy. Mining is taking full advantage of the quick expansion of computers and microelectronics.
The loss of a life is the ultimate tragedy, and over the thousands of years of mining history, the industry has had its share of casualties. Mining deals with the extraction of raw materials like coal, diamond, iron-ore etc. Mining industries can be both open cast mining and underground mining. Although we have improved in the technology and study of the earth, mining industry is a very dangerous job. One of the most dangerous work of mining has been mentioned to be coal mining in which they extract coal from underground. Coal mining hazardous mixture of gas and coal dust can form a fatal explosion. As a matter of fact, I reviewed an article that mention the worst coal mining known as the Benxi Hu colliery disaster in China in 1942. “Cost 1,549 lives and is believed to be the worst coal mining disaster ever.” (Limited, 2014)
The velocity of the rock at any given point can be determined by adding it's translational velocity at the center of mass (the orange arrow) with it's rotational velocity.
Hydraulic fracturing, which is the process of natural gas extraction, has been in debate for the past few years. It was first introduced back in the late 1900s, as a beneficial way to obtain clean fuel, and it also benefitted the economy by providing employment for many. However, recent studies have shown that hydraulic fracturing is causin...
Coal has a very negative impact on the environment, one of the main impacts on the environment is the actual process of extracting the coal from the ground. The two ways that coal is mined, underground and surface, both have different effects on the environment. The first way that coal is mined is by digging tunnels and creating mineshafts underground and then removing the coal from th...
Hydraulic Action, when waves hit the cliff, air is forced into cracks, and then as the wave retreats this air expands explosively. Over time the cracks enlarge, weakening the base of the cliff causing erosion.
Mining is the process or industry of obtaining minerals from the earth. Topics in this paper I’ll be specifically discussing are pros and cons of mining, structures of a mine, mining in general, California gold rush, diamonds in Africa, and comparison of diamond and gold mines.
Though it has had many negative impacts on the environment in the past, mining is a vital industry completely necessary to our economy and lives. Nearly every item we use or encounter in our day to day lives is mined or contains mined products. Without the excavation of such materials things like computers, televisions, large building structures, electricity, and cars would not be possible. Virtually every technological and medical advance uses minded materials, without which millions would suffer. Some examples of minerals in the home include the telephone which is made from as many as 42 different minerals, including aluminum, beryllium, coal, copper, gold, iron, silver, and talc. A television requires over 35 different minerals, and more than 30 minerals are needed to make a single personal computer. Without boron, copper, gold and quartz, your digital alarm clock would not work. Every American uses an average 47,000 pounds of newly mined materials each year, which is higher than all other countries with the exception of Japan, which is a staggering figure representative of our dependence and need for mined minerals. Coal makes up more than half of nation’s electricity, and will continue to be the largest electrical supplier into 2020 & accounting for some 95 percent of the nation's fossil energy reserves – nine of every ten short-tons of coal mined in the United States is used for electricity generation. As the population of the world grows more mineral resources must be exploited through mining in order to support the rising demand for such products. Though it may present a hazard to the environment and those physically located nears the mines, the materials extracted from mines...