Basic requirements for choosing a mining method
1) The mining method chosen for safety must ensure that workers can be safely produced during the mining process. Good working conditions (such as reliable ventilation and dustproof measures, suitable temperature and humidity) can mechanize heavy work and at the same time Ensure that mines can be produced safely and continuously, such as avoiding damage caused by large-scale ground pressure activities, preventing damage from surface landslides and mudslides caused by large blasting vibrations and post-harvest rock movements, preventing groundwater disasters, fires and other disasters, etc. .
2) Small ore depletion The selected mining method should be depleted and the ore quality is high, which meets the requirements of the processing department for ore quality. Such as mining open-hearth iron-rich ore, waste rock can not mix ratio is too high and too fine ore, the ore can order directly into the open hearth. The impact of ore depletion on the quantity, cost and profitability of mining products (concentrates) is significant. Under normal circumstances, the ore cargoization rate is marked below 15%-20%.
Note: 1 During the mining process, some of the industrial reserves that could not be produced or mined due to some reasons could not be completely transported out of the surface and lost underground. Any reduction in the amount of ore produced during the mining process is called ore loss.
2 The ratio of industrial reserves to industrial reserves lost during the mining process is called the ore loss rate. The ratio of pure ore produced to industrial reserves is called ore recovery rate. Both the loss rate and the recovery rate are expressed as a percentage (%).
3 In the mining process, not only the loss of ore, but also the quality of the ore, called ore depletion. It has two representations: the ratio of the amount of waste rock mixed into the produced ore to the amount of ore produced is called the waste rock mixing rate; it is caused by the amount of waste rock mixed and the loss of high-grade fine ore in individual cases. The percentage of ore grade reduction is called the ore depletion rate. The incorporation of waste rock during the mining process is the main cause of the depletion of ore. It is mainly in the process of falling mine, because the control of the ore body boundary is not good, the stone is not removed and the ore is discharged under the overburden.
The two indicators of ore loss and depletion are the main indicators for evaluating mineral deposits, each indicating the utilization of underground resources and the quality of ore mined. In metal mining deposits, reducing the rate of loss of ore, waste rock mixed rate and dilution rate, it has great significance. This has great significance for making full use of the national underground resources and extending the life of mining enterprises. At the same time, the loss of ore will inevitably reduce the amount of ore produced, which in turn will increase the cost of capital allocated to the ore mined per ton and increase the cost of mining ore. As another example, a 100 * 104 annual copper ore mine t, 1% of the recovered copper ore grade, ignoring losses in the process, excluding, can produce ten thousand tons of copper annually. When the ore grade is reduced by 0.1%, one thousand tons of metal copper is produced less every year. The increase in the rate of waste rock mixing will inevitably increase the cost of ore transportation, upgrading and processing. At the same time, the lower grade of ore will also lead to a reduction in the metal yield and final product quality of the beneficiation process. Therefore, the economic losses caused by the depletion of ore are enormous.
3) High ore mining rate The mineral resources are limited and cannot be regenerated. Mining is an exhaustive production, so mining methods with high recovery rates are required to make full use of underground resources. In addition to having a certain impact on ore costs, ore losses also reduce total profit and shorten mine production time. Generally, the ore recovery rate should be between 80% and 85%. For the rich ore, rare metals and precious metal deposits with high mining value, the mining method with high recovery rate should be selected as much as possible.
4) High production efficiency It is necessary to select mining methods with high production capacity and high labor productivity. Different mining methods, the number of stages of simultaneous mining, the number of nuggets that can be arranged in one stage, and the production capacity of the nuggets are also different. The choice of mining method is generally considered in terms of the number of nuggets arranged in a recovery stage to meet the mine production capacity. The length of the return mining block is preferably less than two-thirds of the length of the stage working line.
High production efficiency can reduce the number of working nuggets at the same time, and it is convenient for the implementation of centralized mining to facilitate production management and mining site pressure management.
5) High economic efficiency The economic efficiency is mainly the level of the three grades of mine products and the profitability. The profit indicators have the most comprehensive nature, such as the cost of ore and the loss of ore, which have an impact on profitability. Choose a profitable mining method.
6) Compliance with relevant regulatory requirements Mining method selection must comply with the relevant regulations of mine safety, environmental protection and mineral resources protection.
The above-mentioned combined requirements are interrelated and a comprehensive analysis of the above requirements must be made when selecting mining methods.
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