Abvmachinery is a professional mining equipment supplier in China. We will share the knowledge about the mining methods here. Mining refers to the extraction of natural mineral resources with utilization value by hand or by machine. According to the different depths of the deposits and the requirements of technical and economic rationality, mining is divided into open-pit mining and underground mining. Close to the surface and the shallow part of the deposit is open-pit mining, and the deep part is underground mining.
For an ore body, whether to use open-pit mining or underground mining depends on the state of the ore body. If open pit mining is used, how deep should be used is reasonable, and there is a problem of depth boundary, the determination of which depends mainly on economic efficiency. Generally speaking, the realm of stripping such as less than or equal to the economic reasonable stripping ratio, can be used in open pit mining, otherwise the underground mining method.
(A) open-pit mining
Open-pit mining is the use of mining equipment in the open conditions, in the form of hillside open air or depressed open air, a stage by stage downward stripping of rock and extracting useful minerals of a mining method. Compared with underground mining, open pit mining has many advantages, such as fast construction speed, high labor productivity, low cost, good labor conditions, safe work, high ore recovery rate, small depletion loss and so on. Especially with the development of large-scale high-efficiency open pit mining and transportation equipment, open pit mining will be more widely used. At present, most ferrous metallurgical mines in China use open pit mining.
The whole process of building an open-pit mine generally includes: the construction of ground facilities in the mining area; the dredging and anti-drainage of the ore deposit; the basic construction of the open-pit quarry as well as a series of preparatory work for putting into production.
Open-pit mining infrastructure projects are mainly excavation into the car ditch, out of the car ditch and open section of the ditch, laying transportation routes, construction of soil discharge, stripping rock and construction of water supply and drainage, power supply facilities, etc..
The entry and exit trenches are to establish inclined transportation roads from the ground to the working levels and between each working level. The opening trench is a horizontal trench dug at each level to open the mining workings, the initial workings of the opening phase.
Trenching, stripping and mining are three important parts of the open pit production process. The speed of the decline of the open pit mine and the length of the preparation time for the new level are mainly determined by the trenching speed. In order to ensure that the open-pit mine continues normal production, ditching, stripping and mining between the three, in space and time must maintain a certain degree of ahead of the relationship. Follow the “mining and stripping, stripping first” principle of organizing production.
Open pit mine production process, whether it is stripping or mining ore, the process generally have to go through the perforation, blasting, loading and transportation. At present, China’s ferrous metallurgical mines used by the equipment, piercing is mainly a tusk drill and submerged drilling, impact drilling has been eliminated. Most of the loading equipment using 3 to 4.6 meters 3 electric shovel, 6 meters 3 electric shovels are beginning to use. Most of the transport equipment uses more than 20 tons of heavy-duty vehicles and 80 to 150 tons of motor vehicles, 100 tons of electric wheeled vehicles are also used in some of the mega mines.
(ii) Underground mining
When the ore deposit is buried deep below the surface, the use of open-pit mining will make the stripping coefficient is too high, after technical and economic comparisons that the use of underground mining is reasonable, then the use of underground mining method.
Because the ore body is buried deeper, to extract the ore out, must be cut from the surface to the ore body of the roadway, such as vertical shafts, inclined shafts, ramps, alleys and so on. The focus of the underground mine capital construction is to excavate these shafts and alleys project.
Underground mining mainly includes opening up, mining cut (mining and cutting work) and mining back three steps. Exploitation is in order to access the ore body from the surface and excavated shafts, slopes, ramps, alleys and other shaft excavation works. Mining is based on the pioneering works, the preparation work for the return of the ore, including the excavation stage of the flat road, crossroads and shafts and other mining preparation roadway. Cutting is on the basis of pioneering and quarrying project, according to the mining method must be completed before the mining operation, such as cutting the shaft, cutting the alley, pulling the bottom of the roadway, cutting the rift valley, mine funnel, rock drilling chamber, and so on. Return mining is mining in the quarry and includes operations such as rock drilling and chipping the ore, transporting and moving the ore, and supporting the quarry. These three steps are carried out sequentially at first, and when the mine is in operation, it is still necessary to continue to cut various shafts in order to maintain continuous normal production. Such as the extension of the development of the roadway, excavating a variety of prospecting,
Mining, back to mining roadway. In time, must follow the “open up ahead of mining, mining ahead of mining, to ensure that all levels of production to prepare for the amount of ore to reach a reasonable period of retention” of the law of production. This is summarized through the long-term production practice is more in line with the scientific law of mine production practice.
Underground deposit mining, generally the first mining stage, after mining the next stage. In the stage, along the deposit is divided into blocks (block height is generally 40 to 60 meters, foreign generally 60 to 120 meters, or even up to 200 meters), generally to the block as the basic unit or the block is then divided into mine room and pillar mining.
There are many underground mining methods, mainly divided into the following three categories:
(1) natural support mining methods. The mining area is divided into mining houses and pillars. When mining back to the mining room, the hollow area formed, the use of pillars to support, so the basic conditions for the use of this type of mining method is that both the ore and the surrounding rock need to be stable.
(2) Artificial support mining method. In the mining area, with the advancement of the back-mining face, the artificial support method is used to maintain the hollow area and form the working site.
(3) Avalanche mining method. It is a method to control and manage the ground pressure by filling the mining void area with the crumbling of ore and crumbling surrounding rock. Because the upper and lower disk rock fall will cause the collapse of the ground surface, so the ground surface is allowed to fall is a necessary prerequisite for the use of this type of mining method.
Underground mining, whether it is pioneering, quarrying or mining back, generally through rock drilling, blasting, ventilation, loading, support and transportation and lifting processes.
At present, China’s key underground mines use equipment, rock drilling is mainly used in rock drills, rock drilling carts and quarry with a deep hole and deep hole drilling rigs. Loading is mainly used loader, shoveling machine, electric rake and so on. Flat road transportation and lifting generally use motor cars to haul columns of ore cars to the shaft, inclined shafts, lifting shafts and sites, and then use the cage to lift the ore cars to the ground, large underground mines will be unloaded into the ore mine, and then loaded into the skip lifted to the ground!
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