Outburst danger

OUTBURST DANGER (EN: outburst danger, outburst hazard; DE: Ausbruchgefahr; FR: danger de degagements instantanes, aptitude aux degagements instantanes; ES: peligro de erupciones; RU: выбросоопасность) is the probability of the emergence of the outbursts of mainly coal or rock and gas (less often of the certain sandstones from the coal-bearing depositions, and of the potassium salts) during the conducting of the mining works; the outburst danger is identified on the basis of the accounting of the sudden outbursts, which have emerged earlier, and using the means of the forecast.

They distinguish: the regional forecast of the outburst danger, which is based on the geological exploration, on the analysis of the geological situation within the limits of the deposits, of the regions, or of the underground mine fields; the local forecast, which takes into account the signs of the outburst danger, which are found during the process of the conducting of the mining works, and which characterizes mostly the changing of the properties and of the gas-dynamic regime within the coal layers and surrounding rocks; the current forecast, which is performed continuously, with the advancing of the mine workings, which is based on the registration of the harbingers for the outbursts (for example, the acoustic forecast, and the seismic-acoustic forecast), and which characterizes the dangerous status of the productive layer, or of the rocks.

The signs of the outburst danger are the increasing of the rock pressure, the increased gas content of the coal and rocks, the decreased strength of these coal and rocks, the heterogeneity of the structure, which is often confined to the geological disturbances, and others. The outburst danger increases with the increasing of the depth of the mining works. The outburst danger is characterized quantitatively, using the partial indicators, on the basis of the correlational analysis of which, there is computed the comprehensive indicator for the outburst danger.

According to the outburst danger, the coal layers are divided into non-dangerous, threatening, and dangerous; the surrounding rocks are divided into dangerous and non-dangerous. The coal layers and rocks, which are threatening and dangerous because of the outbursts, are developed with the usage of the protective activities (see the "Sudden outburst" article).