Study on division of mining area under influence of production capacity increasing of open-pit coal mine

Abstract

It is of direct and great significance for increasing the economic benefits of mining by improving the production capacity of open-pit coal mines. Based on the mining status of an open-pit coal mine in Zhundong of Xinjiang, in view of the development goal of expanding its production capacity from 20 Mt/a to 50 Mt/a, the development requirements of the mining areas in line with the 50 Mt/a production capacity well be studied, as well as the optimal mining areas division and development relationship will be determined affected by capacity increase. The technically feasible and economically reasonable working face length of the open-pit coal mine is calculated as 2300~2500 m for the capacity expansion, and according to the optimal working face length and the contour map of the stripping ratio of the whole mining areas, four reasonable mining areas division schemes are proposed. By analyzing and determining the disadvantage and advantage of various mining area division schemes, mine indicators are adopted as impact indicators for evaluating mining areas division, such as the average working face length, the secondary stripping amount, the variation trend of the stripping ratio of each mining area, the stripping ratio of the first mining area, the early external-dumping transportation distance, and the difficult degree of internal-dumping, the numbers of mining areas connection, the exploration degree of the first mining area, and the difficult degree of mining areas connection. While the set-valued iterative method is combined for calculating index weight, a comprehensive evaluation model of the mining area division scheme is developed by adopting the method of TOPSIS. The research results show that the mining area is gradually advanced to the southwest for about 4000 m with the current mining position as the first, and then advances to the east through a 90° fan-shaped turning to the east boundary, which is the second mining area, and then the remaining unexploited mining fields are divided into third and fourth mining areas arranged in parallel Area. The stripping ratios from the first mining area to the fourth mining area are 1.85 m3/t, 3.04 m3/t, 3.68 m3/t, and 5.06 m3/t, respectively. The stripping ratio gradually increases with the continuous advance of the mining area, and the stripping ratio is evenly distributed in the four mining areas. In addition, the mining area division scheme can achieve small secondary stripping volume and early discharge distance, less connection times, high exploration degree in the first mining area and uniform working line length in each mining area under the condition of meeting the production capacity of 50 Mt/a, and has the minimum impact on the overall development of the mine and the economy.

Keywords

• open-pit coal mine
• capacity increase
• mining area division
• set-valued iterative method
• topsis evaluation method