SU1209861A1 - Method of current forecasting and monitoring of outburst hazard of rock body - Google Patents

Description

The invention relates to a mining section and can be used to estimate the stress state of a coal seam, predict the potential outburst hazard of a seam, to combat rock bursts and sudden outbursts of coal and gas.

The aim of the invention is to improve the accuracy and speed of control.

FIG. 1 shows the placement of the sensor on the surface of the formation during the measurement; in fig. 2 shows the layout of the sensors in the preparatory development; in fig. 3 is a diagram of the placement of sensors in the clearing making; in fig. 4 is a graph showing the change in potential of a geoelectric zero measured at the bottom of a vent shchreka (horizon 740 m), where with dynamic explosives a gas-dynamic phenomenon with a capacity of 185 tons occurred.

The method is carried out as follows.

Sensor 1, measuring the sign and magnitude of the potential of the geoelectric field, is alternately located at the edge of the formation 2 alternately at different points 3 depending on the formation thickness iio, and along the bottom length in accordance with the selected E1M measurement scheme option. The frequency of measurements across the reservoir is chosen so as to exclude possible penetration of the danger zone, and is equal to the interval between 1 in the prediction of the initial rate of gas release, for example 10 m. For detecting a dangerous pack, the number of points of reservoir power must be at least the number of packs smoothing the reservoir. The sensor-to-distance distance is chosen so as to eliminate the influence of the electric fields of the host rocks on the sensor readings, and remains unchanged during the production of the measurement cycle. The elimination of the influence of electric fields in the sense of independent breeds is achieved by using an input diaphragm in the sensor design that limits the field of view of the device. The sensor reads on the display unit 4. After moving to the bottom, the measurements are repeated. The potential value at each measurement point is compared with the value before the advancement at the same points, and when exceeding the potential: 1a geoelectrical floor, measured after the advancement, to the value measured before advancement

five

0

five

0

0

five

The NOY value of the plot is referred to as being released.

The threshold value of the change in the potential of the geoelectric field per cycle of the opening is established experimentally or by calculation. Experimentally, the threshold value is set on the schachton layer according to the actual outburst hazard at the bottom with competitive blasting m. According to the graph of the change in the potential of the geoelectric field in the excavation, when starting the bottom of FIG. 4, the ejection during the explosive blasting of the nozzle occurred after the start of a sharp change in the growth slope of the potential of point 5–8. According to the potential values at point 6, it was 0.6, at point 7 - 0.7, at point 8 - 2.25 per step of movement. After the last increase, with the explosive blasting, the projection eaten out. Based on this, over the threshold value, an increase in the potential of the geoelectric field per pushing cycle of 2 times is taken.

The theoretical calculation of the reference value from the potential of the geoelectric potentials; 1 is based on the idea of localizing the sources of the field in the zone of the reference pressure, 1 and the inversely proportional dependence of the magnitude of the field from the distance to the sources. If, with the advancement of the slaughter in separate areas of the reservoir, the support pressure zone approaches the face, then the potential of the geo-e-floor field increases. The critical value of the ratio of potentials is selected from the condition of the dangerous proximity of the non-stressed section of the reservoir to the bottomhole equal to 3 m. Since the reference pressure zone for the reservoirs is on average 6–10 m from the reservoir edge, the reference potential ratio is 2.

The diagrams for the exchange of sensors may differ from those presented and take into account the features of specific workings. For the production of measurements, a single sensor can be used and a system for moving it down the face (manual, mechanized) or a system of sensors, each of which controls a certain area of the face. Electrometers such as a capacitance probe, a dynamic capacitor, etc. can be used as sensors, allowing you to measure the sign and size of the field formed in the formation of surface reservoirs.

Fg / g.2

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Claims (1)

METHOD FOR CURRENT FORECAST AND CONTROL OF EMISSIONS OF ROCK MASS, including measuring the value of the potential of the geoelectric field in front of the face of the treatment and preparation workings, characterized in that, in order to increase the accuracy and efficiency of monitoring, the value of the potential of the geoelectric field is measured along the bottom line before and after it is moved by the sensor installed at a given distance from the bottom, and then compare the ratio of potential after moving to the value of potential before moving with a given reference value HAND, wherein portions of a rock mass, in which the ratio is equal to or above a predetermined value, referred to outburst. g FIG. 1>