Open-pit mine soft rock slope internal row tracking pressure side control engineering：A case study at the south side of the first mining area of Hesigewula south open-pit coal mine

Abstract

Slope stability control is crucial for safe and efficient coal mining in open-pit mines with soft rock. To address the challenge of stabilizing dip soft rock slope rock slopes, the treatment engineering of inner row tracking pressure side of dip soft rock slope in open-pit mine is proposed based on the analysis of the main controlling factors of slope stability. This study takes the south side of the first mining area of Hesigewula south open-pit coal mine as the engineering background and proposes a synergistic treatment scheme for the slope stability of the stope and inner dump, utilizing the combination of limit equilibrium method and numerical simulation to design the spatial form of the stope slope. This treatment scheme maximizes the safe recovery of the coal resources covered by the slope. The research results indicate that the length of exposed weak layer is the primary controlling factor of the stability in inclined soft rock slopes in open-pit mines. Controlling the tracking distance between the stope and the inner dump is an effective way to improve slope stability. With an increase in tracking distance, the slope damage mode transitions from the cut-layer-sublayer-shear-out sliding with an arc as the side interface and the weak layer as the bottom interface to cut-layer-sublayer sliding with an arc as the side interface and weak layer as the bottom interface, leading to a gradual decrease in slope stability. Moreover, the stability of the inner dump and its composite slope with the stope increases exponentially with an increase in the backfill rock range of the weak layer of the failure floor. The study sets the shallow slope of the south slope of the first mining area of Hesigewula coal mine to be 40 m transportation flat and 15 m security flat, and the deep slope angle of the bottom slope is 29°. When the tracking distance is controlled within 50 m, it can meet the safety requirements. When the weak layer of the inner dump base is destroyed, and the inclined length of the backfill rock is 60 m, it can also meet the safety requirements. The study provides new insights into slope stability control in soft rock open-pit coal mines.

Keywords

• open-pit coal mine
• downdip soft rock
• inner row tracking
• pressure governance
• spatial form
• slope stability