Gases Emission in Underground Coal Mines and its Controlling Measurements


  • Lingampally Nitish
  • Mr. Vinay Kumar Patel


The amount of methane (CH4 ) released during coal mining depends on a number of factors, the most important of which are coal rank, coal seam depth, and method of mining. Underground coal mining releases more methane than surface or open-pit mining because of the higher gas content of deeper seams. Total national emissions from coal mining, regardless of the selected methodology, should be calculated as the sum of emissions from underground mining, surface mining, post-mining activities, and emissions avoided due to recovery. The Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories (IPCC Guidelines) provide two general approaches to estimating CH4 emissions from coal mining. The first approach, outlined in the Tier 1 and Tier 2 methodology is based on coal production and an emission factor. The second approach, the Tier 3 method, uses mine-specific measurement data from ventilation and degasification systems to develop national estimates for underground mines. For countries with significant underground mining, the Tier 3 method is much more reliable because it takes into account variability in geologic formations and mining practices. The difference between Tier 1 and Tier 2 emissions factors for coal mining is that Tier 2 requires measurement data from underground mines within the country itself. Generally, for both Tier 1 and Tier 2, the uncertainty in the activity data (coal production) is low compared to the uncertainty in the emission factors. Ventilation data from underground mines are much more accurate, typically being accurate to within 20 percent. Important considerations for completeness include emissions from abandoned mines and from waste piles, although currently no methodologies exist and data are difficult to collect. For reporting of emissions, it is important that countries disaggregate fugitive emissions from coal mining and natural gas systems, and also provide information on the method and emission factors used.