Mining Publication: Measuring the Methane Content of Bituminous Coalbeds
Original creation date: January 1975
The methane content of virgin bituminous coalbed can now be measured accurately in the field with exploration core samples from vertical boreholes. The gas content of the coal per unit weight can be used either to design a mine ventilation system or to determine if degasification of the coalbed will be necessary before mining, and to determine the gas resources in the coalbed. The equipment necessary to conduct the test costs less than $50. The gas content of the coal in place in the ground is determined by summing the gas lost from coring, gas measured during desorption, and the residual gas in the coal. Upon removal from the borehole, the core sample is placed in an airtight container and desorbed for several weeks until the desorption rate is below 0.05 cm3/g for 5 consecutive days. The gas lost from the core while it was being cored and the residual gas are estimated by a new graphical method. The amount of gas remaining depends upon whether the coal is friable or blocky. Friability appears to relate to the depth of the sample below the surface, fixed carbon percentage, Hardgrove grindability index, and proximity to tectonic disturbance. Friable coals emit nearly 96 pct of the total gas during desorption whereas a blocky coal emits only 60 pct of its total gas. Coalbeds that are ill defined as to their blocky or friable nature must be tested in the laboratory for unambiguous analysis.
Authors: CM McCulloch, JR Levine, FN Kissell, M Deul
Report of Investigations - January 1975
NIOSHTIC2 Number: 10000625
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 8043, 1975 Jan; :1-22
- The Borehole Monitoring Experiment: Field Measurements of Reservoir Conditions and Responses in Longwall Panel Overburden During Active Mining
- Coal Mine Methane: A Review of Capture and Utilization Practices with Benefits to Mining Safety and to Greenhouse Gas Reduction
- Methane and Dust Controls for Longwalls: Pocahontas No. 3 Coalbed, Grundy, Va.
- Methane Drainage: Experience With Hydraulic Stimulation Through Slotted Casing
- Methane Gas Content of the Mary Lee Group of Coalbeds, Jefferson, Tuscaloosa, and Walker Counties, Ala.
- NIOSH Research for Monitoring and Controlling Methane at U.S. Underground Coal Mining Operations
- A Numerical Evaluation on the Effects of Impermeable Faults on Degasification Efficiency and Methane Emissions During Underground Coal Mining
- Review of Horizontal Drilling Technology for Methane Drainage From U. S. Coalbeds
- Three Coal Mine Gob Degasification Studies Using Surface Boreholes and a Bleeder System
- Two-Phase Flow in Coalbeds
- Content source: National Institute for Occupational Safety and Health, Mining Program