3. 1 When the surface state of shallow mined-out area is stable, the possibility of geological disasters is small and the danger is small. However, according to the formula derived by the northern probability integral method, the mining range (that is, the increase range of depth ratio) is predicted and analyzed, but the possibility of inducing geological disasters is medium and the danger is medium; Part of the mined-out area has occupied 2/3 of the mining area, which can be regarded as a large enough trial mining area. The influence of mine geological environment has been fully manifested, and the evaluation opinions on the present situation have been fully representative. When there is no obvious change in the geological mining conditions of the proposed mining area, the corresponding deep or extended mining along the strike should not be predicted and evaluated, otherwise it will be a paradox.
3.2 When "geological disaster bodies (points)", "bad geological bodies" and "buildings (structures) are not found in the evaluation area (including the surface movement and deformation of mined-out areas), it is advisable to make a stable state evaluation, especially in the designated mining influence area. When it is determined that the present situation is basically stable and unstable, and geological disasters are likely, probable, dangerous and dangerous, the basis for such determination must be provided, which should be basically clear: disaster types, location distribution, area and harm objects, with photos attached. Any judgment must be based on sufficient evidence. It is inappropriate to make unfounded judgments.
3.3 When describing geological disasters or unfavorable geological phenomena (bodies) such as dangerous rocks, landslides, mudslides and collapses, the status quo is judged to be stable or basically stable, the possibility of geological disasters is small or medium, and the risk is small or medium. As long as it is on the "medium" line, there should be a basis for the status quo. Generally speaking, the prediction and evaluation are based on the depth ratio and deformation value of surface movement caused by mining. When the possibility of geological disasters induced by mining is medium or large, and the risk is medium or large, the possible disaster types, location distribution, area, harm objects and degree should be analyzed, and the type and distribution of disasters are important. If this analysis and prediction are not carried out, the suggestions of prevention and control measures will lose their foundation; Then the estimation of control cost and compensation (compensation) cost will also lose its basis, which will eventually affect the conclusion of suitability. There is a logical embarrassment.
4. Strengthen on-site investigation to provide sufficient basis for mine disaster assessment.
4. 1 It is the theoretical and professional knowledge preparation that every worker engaged in mine disaster assessment should have to seriously study and study the mining subsidence and the three mining regulations. In the study and application, we should proceed from reality and respect the objective existence. Any empirical theory and formula are limited by the similarity of conditions, so we must overcome the tendency of simplification of "copying" and "applying" and the tendency of being divorced from the actual situation.
4.2 Taking the existing large-scale mined-out areas as experimental areas or trial mining areas for mine exploitation, it is entirely possible to conduct scientific, systematic and comprehensive investigation and study, learn from the existing "theories" and "regulations", and establish a "standard value" reference system for mine disaster assessment in this region. At present, the most important and feasible thing is to strengthen the investigation of the status quo of each evaluation unit, but it is still a weak link.