CS252252B1 - Method of coal and gas break-out's danger detection withh yet carried-up opening - Google Patents

Abstract

The way of detecting the risk of bursting coal and gasses of a discarded mine by drilling exploration wells and measurements desorbable gas carrying values and initial values the desorption rate in situ a sample of drill grit and further the initial values gas production and gas pressures in these exploration wells measured. Exploratory wells are drilled from the mine work in the plains perpendicular to its longitudinal axis, in depth 6 to 12 meters. They drill in the coal seam, all in the same direction. Distance adjacent exploration wells is equal the sum of their depths mine workings on either side of each mine exploration wells are unsafe coal and gas bursts if they are in values of the initial diaper less than 3.0 l.min ”1. Doing so there must also be initial velocity values desorption in situ at a depth of up to 4 meters less than 1.5 cm * / 10 g at a depth of 4 meters or more lower less than 1.3 cnr / 10 g. 35 s / _1 and values lower desorbable gas carrying capacity than 9.0 m5t-1 and measured pressure values gases in mines and methane bursts below 13Ο kPa and in mixed mines bursts below 5θ KPa ·

Description

The present invention provides a method for detecting the risk of bursting of coal and gases of an already excavated mine in a deep coal mine, for which, for objective reasons, this was not performed at the time of the excavation.

The risk of bursts of coal and gases of a previously excavated mine has not yet been identified. If the degree of danger in terms of the possibility of coal and gas bursts can be determined retroactively, the mine will be declared unsafe in terms of the possibility of coal and gas bursts. The disadvantage of the prior art is therefore that it is necessary to comply with costly operational safety measures laid down for dangerous mining works even in those cases where these works are not really dangerous. It is known to measure the initial rate of in situ desorption, desorbable gas capacity, initial gas production and gas pressure to determine the possibility of coal and gas bursts, in which a borehole with a diameter of 30 to 50 mm, 5 to 10 m.

The borehole is sampled to determine the initial in-situ desorption rate and desorptible gas capacity, and to measure the initial gas production and gas pressure values. 0.2 meters before reaching the limit of each full one meter borehole length. The drilling is interrupted only when this limit is reached, where the initial gas production is measured first and then the last 0.5 to 1.0 meter borehole is sealed, and the gas pressure is measured in the chamber thus formed, for borehole lengths of 3 meters. time of 1 minute from the interruption of drilling and in each additional meter of the borehole length this time is extended by max. 0.5 minutes.

These shortcomings of the current situation will be eliminated by identifying the risks of coal and gas bursts, of the excavated mine by drilling exploration wells and measuring the values of desorbable gas capacity and the initial in-situ desorption rate.

252 252 samples, drilling chippings. The drill bits shall be taken from exploration wells at meter intervals starting at a depth of 2,8 to 3,0 m. In addition, the values of initial gas production and gas pressures shall be measured at exploration wells at each exploratory well depth, starting at 3, The essence of the invention is that the exploration wells are drilled from the mine in planes perpendicular to its longitudinal axis, approximately in the same direction, in a coal seam, to a depth of 6 to 12 m. The distance of adjacent exploration wells is equal to the sum of their depths. A section of a long mine on both sides of the mouth of individual exploratory boreholes to a distance equal to the depth of this exploratory borehole is without danger of bursting coal and gases, if the measured exploratory borehole values of initial gas production are less than 3.0 l.min ”! and an initial in situ desorption rate of less than 4 m in depth

1.5 cnr / 10g. Or at a depth of 4 m or more less than 3 — nižší

1.3 car / 10g · 35s / a desorbable gas capacities below 9.0 nrt and gas pressures in methane burst mines below 130 kPa and mixed burst mines below 50 kPa.

The advantage of the method of detecting the risk of bursts of coal and gases according to the invention is that we can determine the risk of bursts in a previously excavated mine work, respectively. to exclude sections of the mine that are not dangerous from the point of view of coal and gas bursts.

When driving the mine in the mine, where mixed rupture occurred, the objective was not to predict the rupture of coal and gases for objective reasons. Therefore, it was not in this work at v

punching to detect the risk of bursting coal and gases. Later there was a need to find out if the mine was dangerous. Therefore, exploration boreholes with a diameter of 42 mm were drilled from the mine work into the coal seam. All exploratory wells were 6 meters deep and were drilled in the coal seam perpendicular to the side of the mine. The distance between the individual exploratory boreholes was 12 meters. All exploratory boreholes were sampled, starting at a depth interval of 2.8 to 3.0 meters. Other drill bits were taken at depth intervals of 3.8 to 4.0 meters, 4.8 to 5.0 meters and 5.8 to 6.0 meters. From these samples, the values of desorbable gas capacity and initial rate of desorption in situ were measured. The measured values of desorbable gas carrying capacity were in the range of 4.5 ra t to 8.2 nrt for all 3 -1 -3 -1 samples thus obtained.

3,252,252 and initial in-situ desorption rates ranged from 0.8 to 1.1 cnP / 10g. 35s / ”^. Exploratory wells were drilled almost without interruption. The break was only when the limit of 3.0 was reached; 4.0 and 5.0 and 6.0 meters, respectively, when the initial gas production was measured and then the gas pressures were measured. The gas pressure was measured so that it was sealed by the sealing probe at the last 0.5 m from the bottom of the exploration well (ie 2.5 to 3.0 m; 3.5 to 4.0 IU, 4.5 to 5.0). m and 5.5 to 6.0 m) and the gas pressure was measured in the chamber thus formed. The gas pressure was measured at boreholes of 3.0 and 4.0 µl in the range of 40 to 60 sec. after sealing the chamber and at depths of 5.0 and 6.0 m in the range of 60 to 120 sec. In all exploratory wells the initial gas production values ranged from 1.7 to 2.4 l.min ¹ and gas pressure values ranged from 15 to 45 kPa, only the third exploratory well measured the gas pressure at a depth of 5.0 meters 55 kPa. The entire mine, except for the 12-meter-long section of the mine in the center of which was the third well, was therefore without danger of bursting coal and gases.

Claims (1)

Method for detecting the risk of coal and gas bursts of an excavated mine by drilling exploration wells and measuring desorptible gas capacity and initial in-situ desorption rates from drill bit samples taken at exploration wells at intervals of 2.8 to 3.0 m Initial gas production and gas pressures, measured at each full meter depth of the exploration well, starting at a depth of 3.0 m, that exploration wells are drilled from the mine in planes perpendicular to its longitudinal axis, approximately in the same direction in the coal seam to a depth of 6 to 12 meters, the distance of neighboring exploration wells is equal to the sum of their depths and the section of the mine on both sides of the mouth of the individual exploration wells to a distance equal to the depth of the exploration well is safe if they are in this survey Measured values of initial gas production below 3.0 l.min ^-1 and an in situ desorption rate at depth up to 4 m below 1.5 cm / 10 g. 35s /, optionally at a depth of 4 m and more than 1.3 cnr / 10g. 35s / a desorbable gas capacities below 9.0 nrt and gas pressures in methane burst mines below 130 kPa and mixed burst mines below 50 kPa.