Coal mass rating with regards to outburst and coal burst

Outbursts and coal bursts pose significant risks to underground coal mine workers. The burst propensity of a coal seam is represented by the three factors of the burst triangle: coal, energy, and isotropic mass. The most critical factor was determined to be isotropic mass controlling the storage potential and release rate of burst energy. The changing isotropic mass of several coal seams were measured using Coal Mass Rating (CMR). The CMR is a ratio analysis of Uniaxial Compressive Strength (UCS) results that produces three CMR metrics: CMR FROM UCS, CMR from Young’s Modulus, and combined CMR. The first hypothesis tested for a correlation between burst coal with higher CMR values relative to increased carbonate concentrations, where the carbonates fill the fractures in the coal mass. In circumstance, the infilling of the fractures by the carbonates is observed to bond coal clasts. The first hypothesis concluded that elevated carbonate concentration in a coal mass was a primary indicator of bonding but not confirmation of an elevated CMR. The CMR analysis presented a trend between a higher CMR and an increased burst propensity. Based on the CMR trend, the increased burst propensity was correlated to the coal samples' extent of fracturing. Based on the CMR and fracture rating, a positive correlation of the burst samples was achieved with greater than 80% identification, validating the importance of the CMR analysis in the research. A second hypothesis tested the effect of the seam gases carbon dioxide (CO₂) and methane relative to the mobilisation of carbonate in the coal mass fracture networks. The second hypothesis confirmed that CO₂ enabled the mobilisation and deposition of carbonates into the coal fracture networks caused by the groundwater becoming acidic in the presence of CO₂. Numerical modelling was used to test the relationship between a higher CMR and the occurrence of bursts. The numerical modelling concluded that stresses and strain magnitudes concentrated in a mining excavation boundary, when the coal has a higher CMR value. The concentration of in the elevated magnitudes of energy in the free edge of an excavation boundary presents a higher burst potential.

Grantor dc:publisher

UNSW, Sydney

Year dc:date

2025

Author dc:creator

• Anderson, James

• Outburst Coal Burst Isotropic CMR Coal Mas Rating
• anzsrc-for: 40 ENGINEERING

Statement dc:rights

• open access
• CC BY 4.0
• free_to_read

Licence

• https://purl.org/coar/access_right/c_abf2
• https://creativecommons.org/licenses/by/4.0/

Language dc:language

en

Identifier

https://doi.org/10.26190/unsworks/31118

OAI identifier oai:identifier

oai:unsworks.library.unsw.edu.au:1959.4/104851