RU2541347C1 - Method of forecast of location of lower boundary of explosive gas zone in stope - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method of forecast of location of lower boundary of explosive gas zone in working face is proposed, comprising the driving of bypass in working area, implementation of well into the top of layer, and measurement of methane concentration along its length by the moving gas metering probe. At that the well into the top of layer is carried out from the junction of lava with adjoining air release working in the direction of the worked-out area of the current working area to placement of immediate mine roof to the length equal to its pitch of placement, at an angle of unloading of roof rocks from moving boundary of the stope. The measurement of methane concentration is made along the length of the well with the forward and reverse movement of gas measuring probe in preassigned intervals of length of the well, and the lower boundary of explosive gas zone is set from the top of layer along the lower concentration limit of explosibility of gas-air mixture.

EFFECT: implementation of the method enables to establish, in each specific case of mining coal bed, the location of the lower boundary of explosive gas zone in the working face in the most dangerous part of it, to make recommendations to eliminate accumulations of explosive gases, and to improve the safety of stoping on the gas factor.

Description

The invention relates to mining, mainly to the coal industry, and can be used to develop measures to improve the safety of treatment work on the gas factor.

A known method for predicting the location of the lower boundary of an explosive gas zone in the worked out working face of a methane-rich coal mine, including conducting degassing wells from producing coal in the roof of a coal seam with periodic collapse of roofing rocks, measuring methane concentration in wells at various distances from the working seam roof ( Gas emission control in coal mines during cleaning works / I.V. Sergeev, V.S. Zaburdyaev et al. - M .: Nedra, 1992. - 256 p.).

The disadvantage of this method is the complexity of the process of experimental determination of the location of the lower boundary of the explosive gas zone in the worked out face of the working face by the concentration of methane in degassing wells.

There is another method for predicting the location of the lower boundary of an explosive gas zone in a production face, including conducting a degassing well from a local mine in the formation roof, measuring the methane concentration in the well along its length with a movable gas probe using gas-air mixture sampling tools and determining methane concentration in them (Methodical recommendations on the procedure for the degassing of coal mines (RD-15-09-2006). Series 05. Issue 14 / Coll. Aut. - M.: Scientific and Technical Center for Safety in Industry, 2007. - 256 from.).

The disadvantages of this method include the duration and difficulty of performing operations to measure methane concentrations along the length of the well.

The closest is a method for predicting the location of the lower boundary of an explosive gas zone in a mining face at a mining site prepared by parallel workings, including conducting a well into the roof of the formation, measuring the methane concentration along its length with a movable gas probe (Instruction for the degassing of coal mines. Series 05. Issue 22 . - M .: CJSC STC for Research on Industrial Safety Problems, 2012. - 250 p., Prototype).

The disadvantage of this method is the duration and complexity of operations in a well disconnected from the vacuum network for measuring methane concentration in the intervals of the well along its entire length.

The aim of the invention is to reduce the number of intervals along the length of the well and to reduce the time it takes to establish the location of the lower boundary of the explosive gas zone in the roof of the formation face when its rocks collapse.

According to the invention, the goal is achieved by the fact that in the method for predicting the location of the lower boundary of the explosive gas zone in the working face, which includes driving parallel workings in the excavation section, conducting the well into the roof of the formation and measuring the methane concentration along its length with a movable gas probe, the well is carried out into the roof of the formation from the interface of the lava with the adjacent air outlet in the direction of the mined space of the current excavation section, while the well is carried out to planting a direct roof to a length equal to the step of its landing, at an angle of unloading of roof rocks from the movable face of the face, measuring the methane concentration along the length of the well is carried out with forward and reverse movement of the gas probe in predetermined intervals of the length of the well, and set the lower boundary of the explosive gas zone from the roof of the reservoir at the lower concentration limit of the explosiveness of the gas-air mixture.

The method is as follows.

In the extraction section of the gas-rich mine, prepared by parallel workings, a well is drawn into the roof of the formation from the interface between the lava and the adjacent exhaust outlet in the direction of the worked out space of the existing extraction section. In this case, the well is carried out before planting the rocks of the immediate roof to a length equal to the step of planting it, at an angle of unloading of the rocks of the main roof from the movable boundary of the working face.

The concentration of methane along the length of the well is measured by sensors placed in the gas probe during its forward and reverse motion with measurements at the predetermined points of the length of the well, determined by the length of the components of the casing, that is, at the joints of the pipes.

The lower boundary of the explosive gas zone is established from the top of the formation according to the lower concentration limit of the explosiveness of the gas-air mixture, which is set for methane or a mixture of explosive gases (hydrogen, methane homologs, etc.) by sampling and determining the gas composition in them according to standard methods for exploration or during the operation of the field. The parameters of gas-air mixtures (pressure, flow rate, methane content) are determined in accordance with the regulatory document.

The implementation of the method will allow to establish, in each specific case of coal seam mining, the location of the lower boundary of the explosive gas zone in the face in the most dangerous part of it, that is, on the interface of the lava with the air outlet during the return-air ventilation scheme, develop recommendations for eliminating the accumulation of explosive gases and increase safety of gas treatment.

Claims (1)

A method for predicting the location of the lower boundary of an explosive gas zone in a mining face, including driving parallel workings in a mining area, conducting a well into the formation roof and measuring methane concentration along its length with a movable gas probe, characterized in that the well is carried out from the interface between the lava and the adjacent air exhaust in the direction of the worked out space of the existing excavation section, while the well is carried out until the immediate roof is planted at a length of equal to the pitch of its landing, at an angle of unloading of the roof rocks from the mobile boundary of the working face, the methane concentration is measured along the length of the well with direct and reverse movement of the gas probe in predetermined intervals of the length of the well, and the lower boundary of the explosive gas zone is set from the top of the formation at the lower concentration explosive limit of air-gas mixture.