Simulation of Methane Flows in Noncoal Mines

The Bureau of Mines has successfully tested a method to simulate methane (CH4) flows from face areas through the returns of noncoal mines. This technique involves releasing a small quantity of tracer gas at a working area and sampling for that gas downstream in the return airways. By measuring the dilution of the tracer gas, the dilution of any volume of CH4 released at the face can be calculated. This information is useful in selecting locations for CH4 monitors and in deciding the necessity for permissible equipment in the returns.