Stope Structure Parameters Research Articles

Optimization of Stope Structural Parameters in Phosphorite Mine and its Stability Analysis

A mine plans to exploit the low dip thin phosphate deposit by room-and-pillar mining. But a township highway is just above the orebody, and its distance is only 80m, in order to better control the ground pressure in stopes and ensure the operation security, the size of room and pillar must be reasonably designed to maintain the stability of stopes and surrounding rock. The 3D-σ numerical simulation method was applied to analyze the surrounding rock stability in different stope structure parameters. The results show that when holding the size of pointed prop unchanged, the surrounding rock stability would decline with the increase of room width and pillar spacing, for security, the mining plan, the pointed prop is 3×3 m, the stope width and pillar spacing is not more than 9 m, were considered to be one of the optimal. In addition, it is important to emphasize that if the mining depth exceeds 300m, some methods, such as decreasing the spacing of stope and pointed props or increasing the pillar size, need to be taken to avoid the stope instability caused by greater ground pressure.

Application of Fuzzy Comprehensive Evaluation in Stope Structural Parameters Optimization

Alternate Room-Pillar Mining Method with Ascending Backfill is now used in deep mining of Sanshandao Gold Mine. In mining practice of the metal mines, the widths of the room and pillar vary from 6m to 15m. In order to improve the production capacity and solve the deep mining safety problems, a fuzzy optimization model containing 11 evaluation indexes was built to choose the optimal structural parameters among 8m×8m, 8m×10m, 10m×10m, 10m×12m and 12m×12m. The fuzzy comprehensive evaluation results prove that the optimal stope structural parameter is 10m×10m for safety and high efficiency mine operation.

Optimization and Tests on the Independent Advance of Ore Breaking with High Sublevel and Large Drift Interval

According to the mining conditions and equipment level of Xingshan iron mine, optimization research on the stope structural parameters of sublevel caving was made, and finally adopted the structure parameters with 15m sublevel height and 20m drift interval. In order to find out the rational independent advance of ore breaking under 15m×20m structural parameters, theoretical arithmetic and industrial tests were carried out. The tests show that the rational independent advance of ore breaking drift interval should be 3.4m, and the optimized structural parameters of 15m×20m×3.4m has excellent effects on reducing mining cost and improving mining recovery rate.

Optimization of Stope Structure Parameters in E’xi Iron Mine Based on Rock Stress Analysis

Underground mining causes the redistribution of surrounding rock stress. The value of rock stress is one of the important factors that should be considered when stope structure size is designed. E’xi iron ore body is gently declined in attitude, thin in thickness, and large in occurrence area. According to mining technological conditions and the selected mining method of E’xi iron mine, a typical section of the mine is selected, and it is abstracted into a plane strain problem. In terms of optional stope structure parameters, 9 calculation schemes are planed. Rock stress distributions of stope caused by mining are simulated by the Finite Element Method. Rational stope parameters are chosen by comparing stress distributions of all calculation schemes. Analysis result shows that 8m net distance between pillars, and 4m pillar width are the optimum stope parameters, which not only stabilize the stope but also improve mining efficiency. Choosing stope parameters based on rock stress distributions calculated with numerical simulations, is provided a scientific analysis method for determining rational mining parameters of underground mines.