Study on gateway driving technology along goaf applied to layout of displaced layer gateway in ultra thick seam

Based on the less application of the gateway driving technology along the goaf under the layout condition of the displaced layer gateway in the ultra thic k seam, a study was conducted on the gateway driving technology along the goaf in the displaced layer seam. When a mining gateway made in different layer of the ultr a thick seam, different size triangle seam would be left. A theoretical calculation method was applied to the analysis on the stability of the triangle seam. During the mini ng of the 14 m ultra thick seam, the mining gateway was set in a level with 7 m and 10.5 m to the seam floor and the triangle seam under the level of the gateway was i n a stable status. Based on the circumstances, a further study was conducted on the stable triangle seam affected to the stability of the seam under the condition of the gateway support. When the mining gateway layout was determined at a level with a vertical distance of 10.5 m to the seam floor, from the consideration on the stress di stribution and the surrounding rock stability, a layout of the gateway driving along the goaf with non coal pillar could be fully realized. The results showed that under the condition of the displaced layer gateway layout in the ultra thick seam, the gateway driving technology along the goaf could effectively improve the support and the mini ng and driving connection problems of the gateway driving along the goaf.