Design and first application of special-shaped combined section open-off cut in thin coal seam

To address the challenges of rapid excavation in low-mining-height open-off cuts within thin coal seams and the efficient installation and transportation of fully-mechanized mining support, a design scheme was creatively proposed based on the existing mining and excavation equipment, auxiliary transportation modes, and geological conditions at Jisan Coal Mine. This scheme involved the design of section parameters for the open-off cut, specifically the 'roof bench + floor level' special-shaped combined section open-off cut. The open-off cut section was divided into two distinct areas: a support installation space and a vehicle operation space. The net width×net height of support installation side is 4.0 m×1.5 m, and the net width of vehicle operation side is 4.0 m×2.8 m. Both sides of the floor were horizontal, with the height difference established at the roof level.The excavation horizon for each section of the space was clearly defined. This design scheme has been successfully implemented at the 23_上04 working face, achieving rapid excavation of thin coal seam working faces under existing mining and excavation equipment and auxiliary transportation conditions, as well as the safe and efficient installation of fully mechanized mining equipment.