Longwall Mining Under Linear Structures--A Case Study

In a longwall section that consisted of 7 longwall panels, there were two high pressure gas transmission pipelines across the panels burying from 3 to 10 ft. below the surface. One pipeline was 20 in. in diameter while the other was 24 in. in diameter. In order to investigate the stress conditions sustained by the pipelines during underground longwall mining, strain gages were mounted on the pipelines above panel #3, #4, and #5. Survey monuments were also installed along but near the pipelines. This paper presents a subsidence prediction method and the preliminary results of the pipelines' stress conditions as affected by underground longwall mining.