Treatment Project Evaluation for Bench Pinch-out in Nearly Horizontal Open-pit Mine

The bench will pinch out near the coal seam roof when the bench of working slope is horizontally partitioned if large nearly horizontal open-pit coal mine use cross mining sequence. Bench pinch-out will cause an increase difficulty in mining blasting, an increase in distance for stripping and the decrease in the efficiency of shovel. The article proposed three solutions for the problem and selected seven indicators to establish evaluation index system with the ideal solution. Evaluation model was established dealing with the bench pinch-out in Harwusu Open-pit Mine. The result showed that "flying geese pattern"bench group was the most reasonable, which provided a decision-making basis for the site engineering design and production management.