SU1647154A1 - Method of locating outburst-prone face-adjoining zone of coal bed - Google Patents

Abstract

The invention relates to mining promet and m. used in the development of coal seams prone to sudden emissions of coal and gas. The purpose of the invention is to improve the accuracy and reliability of determining the non-hazardous pre-break zones of coal seams during mining operations. The invention relates to the mining industry and can be used in the development of coal seams prone to sudden outbursts of coal and gas. The purpose of the invention is to improve the accuracy and reliability of determination of the emitted hazardous areas of coal seams during mining operations by taking into account changes in the stress state and gas state of the reservoir. The method is carried out as follows. works by taking into account changes in the stress and gas state of the reservoir. From the borehole, drill holes in the interval and seal their mouths. Gas volume is measured during drilling and cleaning of the bore-hole, the output of drilling fines, the time of drilling and cleaning of the bore-hole at a depth of 5–10 m and determine the stabilized value of the maximum effective gas content (EG) before the next extraction cycle. Then, the magnitude of the main compressive stresses, the tensile and compressive strength of the coal, the parameters of the sorption isotherm, the porosity and the temperature of the coal seam are determined. These parameters establish the critical value of the EG by the above formula. The maximum EG value is compared with its critical value, and the outburst hazard of the formation is estimated from the comparison results. If the maximum EG value is greater than the EG critical value, the zone of the reservoir is considered outburst-hazardous, and if the maximum EG value is less critical, the zone of the reservoir is considered non-hazardous. Before each successive nth cycle of coal extraction from the bottom of the preparatory or cleaning development of the drill hole hole. Moreover, in the preparatory development, the determination of the maximum stabilized gas content is made by two boreholes, which are drilled at a distance of 0.5 m to the left and right of the walls of the excavation. And in the sewage disposal sites proceed as follows. With a solid development system, boreholes are drilled in the upper, lower lava clump and in the middle, with a pillar design system СЬ ьл 1

Description

10-15 m of ventilation and haulage drifts and in the middle. Boreholes are drilled in places of geological disturbances. First, drill a hole with a diameter of 70 - 76 mm to a depth of 0.5 - 1.0 m. The hole of the hole is sealed with a PIU-1 device. Then a hole was drilled with a diameter of 42 mm and at each meter interval, starting from the 1st interval, the volume of gas released during drilling and spacing (cleaning) of the interval was measured.

borehole V. gassing before and after drilling H and la, the time of drilling and unstitching t, the mass of the separated stagnant m and determine the effective gas content on each

drilling interval. The maximum value of this lawn is established and its value is compared with the critical value HMKF). which is determined depending on the additional parameters of the stress and

gas state of the reservoir by the formula

Xcr (n) -

where 7i un is the main compressive stress, Pa;

y-specific gravity of rocks, at 2.5 104N / m3; H — depth of mining, m; Rorp (n) is the tensile strength of coal. Pa;

Ксж (п) - ultimate strength of coal for uniaxial compression. Pa;

this is the porosity of coal, unit, determined by the formula

GPO

where d is the apparent specific weight of coal, kg / m3;

d is the true specific weight of coal, kg / m3; about. 1, and g the experimentally determined coefficients, depending on the speed of unloading of the free surface and the structure of the coal, for the outburst coal is taken as 1 0.33; a g 0.022;

lo - depth of entry when excavating coal, m;

q is a constant coefficient q G72.4 J / (K m3);

Zo is the constant of the Langmuir equation, determined by the results of laboratory analysis of coal samples collected in the mine generation by building sorption isotherms or by empirical formulas, m / kg;

b is the constant of the Langmuir equation, determined by the results of laboratory analysis of coal samples sampled at the mine bottom by building sorption isotherms or by empirical formula taking into account the temperature of the coal seam, Pa;

T is the temperature of the coal seam, K;

1k (n) is the distance from the reservoir edge to the maximum concentration of stresses, determined before each nth cycle of coal excavation using hydraulic pressure sensors DDS-1, m.

+ a0

The values included in Xcr, such as the porosity of coal t0. apparent d and true d densities are determined by laboratory analysis of coal samples taken at the bottom of the mine. Depth of entry 10 is accepted according to the mining certificate.

The temperature of the coal seam is determined from geological data, in the case of their absence by the formula

T g

("

N-at at

) +273. TO,

five

0

t

where ti is the average annual temperature over the Earth’s surface, degrees, C;

at - geothermal stage in the basin, m / 1 ° C.

ho — depth of the zone of constant annual temperature, m; .

H - depth of mining management, m

The values of b, ao, to, m0, d, 5, cri, T are determined once for the given geological conditions of the bedding and mining technology. The values of 1k (p), Kszh (p). Rorp (n) are determined before each nth cycle of coal extraction directly at the bottom of the mine using a P-1 strength gauge.

Comparison of the values of Hmaks (p) and Xcr (p) is made and if Hmaks (n) Xcr (n) - the bottomhole formation zone is considered dangerous due to sudden outbursts of coal and gas.

Claims (1)

Claim Method for Determining the Outburst-Hazardous Zone of a Coal Seam, Including Interval Drilling of Bore Boreholes from the Sinking, Sealing the Ust, Measuring the Volume of Gas Released during Drilling and Cleaning the Hole, Drilling Output, Drilling Time the interval of the hole at a depth of 5–10 m and the determination by these indicators of the maximum stabilized value of the effective gas content before the next excavation cycle, the estimation of the outburst risk of the formation. by comparing this gas content with its critical values, characterized in that, in order to increase the accuracy and reliability of determining non-hazardous bottom-hole zones of coal seams , 2G / 14L1 a2 Xcr (p) Ol Rorp (p) (p)) "1 t0 2b4 () +. Vr-; aoM -1 (() ™) where a un is the main compressive stress, Pa; y is the specific weight of rocks, 2.5 104N / m3; I am the depth of mining management, m; Roip (n) is the tensile strength of coal, Pa; Ксж (п) - ultimate strength of coal for uniaxial compression, Pa; t0 - coal porosity, unit; b - apparent specific weight of coal, kg / m3; a 1. and h - experimentally determined coefficients, depending on the speed of unloading of the free surface and the structure of mining operations by taking into account changes in the stress and gas state of the reservoir, additionally determine the magnitude of the main compressive stresses, the tensile strength of coal and compression in the process of unloading the reservoir, the parameters of the sorption isotherm and temperature of the coal seam, and the critical value Xcr (n) of the effective lawn formation of the reservoir is set for each reservoir by the formula .vr-; aoM -1 ) ™) + E0 coal tours, for outburst coal is taken as 1 0.33; “A 0.222; | 0 — depth of entry when excavating coal, m: q — constant coefficient, q 372.4 J / (K – m 3); a0 is the Langmuir equation constant, m3 / kg; b is the constant of the Langmuir equation. Pa; T - coal seam temperature. TO;  k (n) is the distance from the reservoir edge to the maximum concentration of stresses, m and, when the effective gas content is less than its critical value, the bottomhole zone of the coal seam is considered non-hazardous.