A longwall N00 mining method includes performing a no-entry excavation and non-pillar mining in N working faces of a new district, and the whole district is provided with an air-return dip, a haulage dip and a track dip, wherein the air-return dip and the track dip are located on one end of the district, and the haulage dip is connected to the other end of the district, and connected to the air-return dip. This method can not only ensure ventilation of the whole coal cutting are, but also when mining is performed in each working face in the district, entries can be automatically formed due to top-cutting pressure release by using a part of a gob area, and thereby it is not required to separately excavate any gateroad entry during mining coal nor need to retain any coal pillar, so as to save resources and improve efficiency.

Various examples are provided related to methane detection in harsh environments. In one example, a method includes drawing a sample of air from at least one first location; delivering the sample to a volume within a sensor block at a second location, where the sensor block includes a gas concentration sensor in communication with the volume; and where a vacuum is applied to the volume within the sensor block to facilitate delivery of the sample to the second location. In another example, a system includes a sampling unit that houses a sensor block, where a sample tube is coupled to an inlet of the sensor block, which includes a gas concentration sensor; an ejector that facilitates delivery of a sample of air from the first location via the sample tube; and a control unit that can receive a gas concentration sensor output from the sampling unit for processing.

A longwall N00 mining method includes performing a no-entry excavation and non-pillar mining in N working faces of a new district, and the whole district is provided with an air-return dip, a haulage dip and a track dip, wherein the air-return dip and the track dip are located on one end of the district, and the haulage dip is connected to the other end of the district, and connected to the air-return dip. This method can not only ensure ventilation of the whole coal cutting are, but also when mining is performed in each working face in the district, entries can be automatically formed due to top-cutting pressure release by using a part of a gob area, and thereby it is not required to separately excavate any gateroad entry during mining coal nor need to retain any coal pillar, so as to save resources and improve efficiency.

The present disclosure relates to the technical field of mine ventilation, and in particular, to a three-dimensional ventilation method and system for mining by 110 construction method in coal and gas outburst mines. The three-dimensional ventilation method comprises: constructing a first process roadway and/or a second process roadway before stopping the working face; forming a first roof-cutting and roadway retaining section by a part of the working face track gate located in the goaf, and/or forming a second roof-cutting and roadway retaining section by a part of the working face transport gate located in the goaf during the stopping process of the working face, so that the air inlet of the first roof-cutting and roadway retaining section enters the gas drainage air return roadway through the first process roadway to form return air, and/or the inlet air of the second roof-cutting and roadway retaining section enters the gas drainage air inlet roadway through the second process roadway to form return air, the three-dimensional ventilation system is constructed by using the gas drainage air inlet roadway and the gas drainage air return roadway, during the conversion from the 121 construction method to the 110 construction method, a complete ventilation system can be formed in the roadway retaining section, real-time monitoring of the roadway retaining section can be carried while eliminating harmful gas accumulation in the retaining section.