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Single Market, creating more opportunities for people and business. This article is about the mining term. Sketch painting of miners stoping at the Burra Burra Mine, Burra, Australia, 1847. From the 19th century onward, various other explosives, power-tools, and machines came into use. In old mines, stopes frequently collapse at a later time, leaving craters at the surface.
They are an unexpected danger when records of underground mining have been lost with the passage of time. A stope can be created in a variety of ways. The specific method of stoping depends on a number of considerations, both technical and economical, based largely on the geology of the ore body being mined. It is common to dig shafts vertically downwards to reach the ore body and then drive horizontal levels through it. Stoping then takes place from these levels. A common method of mining such vertical ore bodies is stull stoping, see below.
Open stoping is generally divided into two basic forms based on direction: overhand and underhand stoping, which refer to the removal of ore from above or below the level, respectively. It is also possible to combine the two in a single operation. Underhand stoping, also known as horizontal-cut underhand or underbreaking stoping, is the working of an ore deposit from the top downwards. Like shrinkage stoping, underhand stoping is most suitable for steeply dipping ore bodies. In overhand stoping, the deposit is worked from the bottom upward, the reverse of underhand stoping. With the advent of rock blasting and power drills, it became the predominant direction of stoping.
In combined stoping, the deposit is simultaneously worked from the bottom upward and the top downward, combining the techniques of overhand and underhand stoping into a single approach. Breast stoping is a method used in horizontal or near-horizontal ore bodies, where gravity is not usable to move the ore around. Breast stoping lacks the characteristic “steps” of either underhand or overhand stoping, being mined in a singular cut. The method requires that the hanging wall and often the footwall be of competent rock as the stulls provide the only artificial support. Cornwall was caused by failure of the stulls holding up a huge weight of waste rock. Square set timbers are set into place as support and are then filled with cement. The cement commonly uses fine tailings.
This is a highly specialized method of stoping requiring expert input. 1860s, and they utilized the waste rock to fill the stopes. Once the top of the stope is reached all the ore is removed from the stope. Long hole stoping as the name suggests uses holes drilled by a production drill to a predetermined pattern as designed by a Mining Engineer. It differs from manual methods such as timbered and shrinkage as once the stope has begun blasting phase it cannot be accessed by personnel.
Holes drilled underground are generally drilled perpendicular, in a radial pattern around the drive. For the blastholes to successfully extract the ore material they must be able to fire into a void in front. A slot is required in every stope to provide the initial void. The slot is often the most difficult, costly and highest risk component of mining a stope. Raise bore, a circular shaft mined bottom up using mechanical rollers to achieve shaft profile. This method works well in larger stopes however requires both access to top and bottom of stoping block. Raise bores work most effectively between 45 and 90 deg.
This method works well for shorter raises between 45 and 90 deg, however it is prone to freezing and may require remedial drilling to extract slot to full height. This method has the advantage of giving geological and geotechnical teams further analysis of the stoping block prior to mining. Boxhole boring, similar to raise boring but less productive as broken material is extracted from the same location as the drill, is used to bore vertically with no top level access required. United States Department of the Interior, Bureau of Mines. When the Bottom of Dolcoath Fell In”.
This page was last edited on 21 September 2017, at 07:49. WOT Community Badge for updatestar. XP, 32 bit and 64 bit editions. Simply double-click the downloaded file to install it. You can choose your language settings from within the program.
Please forward this error screen to sharedip-1666228125. Чтобы выполнить поиск, нажмите “Ввод”. These deposits form a mineralized package that is of economic interest to the miner. Mining operations usually create a negative environmental impact, both during the mining activity and after the mine has closed. Hence, most of the world’s nations have passed regulations to decrease the impact. Unless future end-of-life recycling rates are stepped up, some rare metals may become unavailable for use in a variety of consumer products.
One of the complexes is shown in one of the earliest known maps. The miners crushed the ore and ground it to a fine powder before washing the powder for the gold dust. Mining in Europe has a very long history. Although they had over 20,000 slaves working them, their technology was essentially identical to their Bronze Age predecessors.