Methane watchdog system, a cost effective approach to longwall methane monitoring and control

A method to quantify a concentration of gas, the method comprising:

• drawing, via three-way valve, a sample of air from at least one first location via at least one sample tube, the three-way valve allowing for the sample of air to be drawn from a first side of the at least one sample tube when the three-way valve is energized and a second side of the at least one sample tube when the three-way valve is deenergized, thereby allowing the sample of air to be obtained from different sides of the at least one first location;
• delivering the sample to a volume within a sensor block at a second location via the at least one sample tube, wherein the sensor block incorporates at least one combustible gas concentration sensor in communication with the volume, wherein at least one pump establishes at least one sample flow from the first location to the second location;
• and
• communicating a signal from the at least one combustible gas concentration sensor to a control unit at a third location, the signal corresponding to a combustible gas concentration level measured by the at least one combustible gas concentration sensor.

A system comprising:

• a longwall mining machine;
• at least one sample tube extending from a first location to a second location;
• a sampling unit at the second location, wherein the sampling unit houses a sensor block, wherein the sample tube is coupled to an inlet of the sensor block, wherein the sensor block incorporates at least one gas concentration sensor that is in communication with the inlet;
• an ejector enabled by a supply of pressurized water or air, wherein the ejector facilitates delivery of a sample of air, using a three-way valve for entry of the sample of air into the at least one sample tube, from the first location to the second location via the at least one sample tube, the three-way valve allowing for the sample of air to be drawn from a first side of the at least one sample tube when the three-way valve is energized and a second side of the at least one sample tube when the three-way valve is deenergized, thereby allowing the sample of air to be obtained from different sides of the first location;
• and
• a control unit in communication with the sampling unit, wherein the control unit is configured to receive a gas concentration sensor output from the sampling unit and output the gas concentration sensor output.