ABSTRACT:

There is a large burning area in Xinjiang Laojunmiao open pit coal mine. To ensure the slope safety, characteristics of surrounding rock after baked and burnt were understood through the geological investigations and the rock mechanics tests. The typical profiles of burning area were selected according to the engineering geological characteristics. The safety factors of the profiles in the different final slope angles and the different states were computed through the limit equilibrium method, then the stabilities were analyzed to determine the reasonable final slope angle. The results show that strengths of burnt rock decrease compared with original rock. When the final slope angle of Laojunmiao mine is 36°, the slope safety can be ensured.

1 INTRODUCTION

Due to the dry climate and shallow coal seam in Xinjiang, coal-field fire are very serious. According to statistics (Cai & Wei 2008), there are currently 50 coal-field fire areas in Xinjiang, and the total area is about 570m2, which lead to the loss of more than 15 million t coal. A large burning area is formed after the coal spontaneous combustion, causing a serious impact on safety production of mine. Many scholars have studied the coal spontaneous combustion, burning area and burnt rock and achieved certain results. Ide et al. (2011) delineated the range of coal fires in underground area by magnetic method, and the geomagnetic characteristics were studied and reported. Heffern & Coates (2004) made a detailed study on distribution and cause of the geologic history coal fires in the Powder River Basin of the United States and used a variety of dating methods to date burnt rocks. Hoffman et al. (2004) used differential interferometric synthetic aperture radar to detect the coal fires in northern China. Christian et al. (2009) detected the range of coalfield fires using thermal infrared remote sensing technique. Voigt et al. (2004) conducted a survey to detected and analyzed coal seam fires in north China using integrating satellite remote sensing techniques.

This content is only available via PDF.
You can access this article if you purchase or spend a download.