In recent years, as open-pit mining mines have been transferred to underground mining, in the design and practice of open-pit mining to underground mining, large-scale mining methods are of great significance. Selecting mining methods for large-scale mining, making full use of mineral resources, and safely and efficiently transferring from open mining to ground mining, can obtain the best economic benefits, social benefits and environmental benefits [1-4].
1 The significance of large-scale mining
For mining enterprises, scale generally refers to the establishment of a complete production management system for production, safety, occupational health, environmental protection, etc. under certain resource conditions, investment and financing conditions and technical and economic conditions. The mine has reached an economically reasonable production scale. , to get the best economic benefits, social benefits and environmental benefits. A mining enterprise may adopt different economic and reasonable production scales due to different investment and financing conditions and technical and economic conditions. However, when its own resource conditions, investment and financing conditions and technical and economic conditions are certain, mining enterprises usually have a certain economic and reasonable production scale. Large-scale mining should be carried out in accordance with economic and reasonable production scale.
When constructing a mine, it is generally necessary to carry out construction in accordance with an economically reasonable production scale, and form large-scale mining after production. During the production period, with the changes in resource conditions, investment and financing conditions and technical and economic conditions, the original production scale is no longer economic and reasonable. The mines should be rebuilt or expanded according to the changed conditions to form new large-scale mining.
Tang steel Shirengou iron ore, for example, began construction in July 2001 from open pit to underground mining in a project, the construction scale iron ore 600,000 t / a, achieve economies of scale mining after the completion in 2003. At the same time, the price of ore has risen rapidly, and the investment and financing conditions and technical and economic conditions have changed significantly. In 2003, the second phase of expansion was started, and the new scale was expanded by 700,000 t/a. After the expansion, the total scale of the first and second phases reached 1.3 million t/ a. After the project was put into production in 2005, a large-scale large-scale mining was realized. At the same time, the ore price continued to rise. In 2005, the Tangshi Shirengou iron ore mine began the construction of the third phase, and the iron ore scale reached 2 million t/a. It can be seen that the goal of large-scale mining of mining enterprises is the economic and reasonable production scale under certain conditions.
2 Main mining methods for large-scale underground mining
The ore bodies in the open-pit mining underground mining are all open-pit mining. The surface of the open-pit mining area is generally allowed to fall. In the range where the surface is allowed to fall, the main mining methods for large-scale mining are the caving method and the empty field method.
When the ore is more stable than medium or above, the empty field method can be used. For example, the next phase and the second phase of the Shirengou iron ore open-pit conversion are all carried out by the open field method. The empty field method mining mining column has a large depletion rate of mining loss, and the problems of goaf and ground pressure are prominent, and the treatment is difficult. The problem is more serious when the thickness of the ore body is large. When the open-pit to underground mining, the open-field mining method is generally used for ore bodies with stable or medium-thickness or above in medium and thick ore, and the caving mining method is adopted when thick and medium-thick inclined and steeply inclined ore bodies are used. The caving mining method has low production cost, is safe and efficient, and is widely used. The caving mining method is shown in Figure 1.
The filling method is used when the local table is not allowed to fall, there are environmental requirements, the tailing is limited, or the ore value is high. For example, the Sijiaying Iron Mine North District is not allowed to fall due to the Pingqing Highway, and it is limited by environmental protection requirements. In the long run, the efficient empty field and post-filling mining method will be widely used in open-pit mining. The filling method after the empty field is shown in Figure 2.
3 technical characteristics
According to the statistical analysis of some open-pit mines that have been completed, put into operation, and planned for design, the main technical features of open-pit to underground scale mining methods (including stage height, section height, rock drilling, mining equipment specifications, etc.) See Table 1.
4 Environmental Assessment
The caving mining method with the most application from open-pit to underground mining has the greatest negative impact on the environment. There is surface subsidence, slope collapse, waste rock, wastewater, tailings and other discharges. When mining mining method, the impact on the environment is minimal; The empty field mining method has different impacts on the environment depending on the processing method of the empty area.
When using the caving method to treat empty areas, the impact on the environment is similar to the impact of caving mining on the environment; when filling the goaf, it can effectively protect the environment; using isolation measures to seal and seal the empty area, the impact on the environment Between the two, when the empty area does not fall, similar to the filling method, when the empty area falls, it is similar to the caving mining method. Due to the uncertainty, the measures for isolating the empty area are less used. Where isolation measures are adopted, the environmental impact and safety measures of the isolation of the empty space should be considered.
5 development trend
At present, the main mining method for open-pit to large-scale mining is the caving mining method, which is safe and efficient, but has a great impact on the mine environment. It is easy to cause surface subsidence, slope collapse, waste rock, waste water and tail during the mining process. The mines and other emissions are large.
The overall development trend of open-pit to underground scale mining methods is safety, environmental protection, high efficiency and low consumption. Although the mining method caving low production costs, high production efficiency, but a greater impact on the environment, according to a predetermined number of packets SAWS [2012] 32, the new metal and nonmetal underground mines must be able to demonstrate to the filling method and uses Priority is given to the filling of mining laws. Therefore, in the long run, the number of mines using the filling mining method will increase in the future.
In order to improve production efficiency, reduce costs, and reduce safety accidents, large-scale mining methods will be developed in the direction of high-level, high-stage, high-efficiency mining equipment, and the level of automation will continue to increase.
references
[1] Yang Xu, Jiang Renyi. Demonstration of the overall technical scheme for a large-scale iron ore open-pit underground mining [G]∥王è¿æ•. Ten years of review and prospects of China's mining technology. Beijing: Metallurgical Industry Press, 2012: 110-113.
[2] Jiang Renyi. Similar principle of ore body and design of standard mining method [J]. Modern Mining, 2014(1): 17-21.
[3] Zhang Mingfeng, Jiang Renyi, Su Jianjun. Extension Pukan select lead zinc ore mining method [J] - Arden. Metal Mine, 2012 (11): 49-51.
[4] Zhang Jianyong, Su Jianjun. Selection of mining methods for the third phase of Shirengou Iron Mine [J]. Metal Mine, 2013 (1): 23-26.
Author: Jiang Renyi; CERI (Qinhuangdao) Engineering Technology Co., Ltd;
Article source: "Modern Mines"; 2016.5;
Copyright:
Automatic Film Cutting Machine
Automatic Film Cutting Machine
Flying Man film cutting machine is suitable to cut / die cut for film rolls, including BOPP film, Car window film, PDLC film, PE film, PET film, Plastic film, Polyester film, Protective film, PVC film, PVC shrink film, Stretch film, Sunshine film, Thin film, Tint film, Vinyl film, Window film, etc.
Film die cutting machine, Film die cutter, Film cutter, Film roll cutter, Film roll to roll cutting machine, Film roll to sheet cutting machine, Film sheeter, automatic film cutting machine, auto film cutter, film slitter, film roll cutting machine
Suzhou Flying Man Assembly Automation Co., Ltd. , https://www.flyingmancuttingmachine.com