1. And above 90 % spontaneous combustion occurs in goaf.

2. This paper analyzes the type of drawing off water in goaf, introduces the technology of it at different goaf, and provides the methods of solving the existing questions.

3. Combined with coal characteristics in goaf of fully mechanized top-coal caving, determinant criteria and methods of hazard zone in goaf are determined by theory of coal spontaneous combustion zone.

4. The coal spontaneous combustion in the goaf is one of the main coal disasters.

5. Strata above and below the goaf are de-stressed and fractured by mining activity.