The Methane Rating System and How it is Used to Evaluate South African Methane Contents and Release Rates

The Methane Rating System was developed to give an easy method to the mining industry to determine gas content and release rates during mining, and to measure the rate of change in methane conditions. This is all to ventilate the coal face more effectively. Due to the under-saturated gas conditions of South African coal seams, gas contents are low compared to the rest of the coal producing seams of the world and there are variations within relatively short distances. With this in mind, the authors were given a project to develop and implement a system that would be customized to the South African conditions. The Methane Rating System was developed and implemented, first with Sasol Mining’s Geoscientific Department and later completed by Itasca Africa. The system uses internationally proven direct methods of methane measurement to quantify the contents and emissions combined with an innovative rating system. The method developed is plain and simple to use with relatively inexpensive equipment. The system can be used to give a methane risk rating to mines, in three categories, from the lowest level such as specific area upto a national level. The system has been implemented on 24 collieries in South Africa.