CO2 storage potential of South African coals and gas entrapment enhancement due to igneous intrusions

Changes in optical properties, chemistry, and micropore and mesopore characteristics of bituminous coal at the contact with dikes in the Illinois Basin

“…For example, from CO 2 sequestration point of view, it is expected that both adsorption capacity and injectivity will be modified compared to the zones of the unaltered coal (Saghafi et al, 2008). Understanding of these modifications and their implications, however, requires further rigorous research.…”

Numerical simulation of stress distributions and displacements around an entry roadway with igneous intrusion and potential sources of seam gas emission of the Barapukuria coal mine, NW Bangladesh

“…Intrusions also thermally and geochemically alter coal to form coke and produce methane (CH 4 ) and carbon dioxide (CO 2 ), increasing the threat of spontaneous combustion and outburst (Golab and Carr, 2004). According to Saghafi et al (2008), the presence of an igneous dyke indicates a high intensity of gas emission. High gas emissions occur mainly in the vicinity of igneous intrusions due to an unexpected drop in stress.…”

“…I assume the dyke is linked to igneous intrusion (Islam, 2005) because similar igneous dykes are frequently found in the Gondwana coalfields of India (Singh et al, 2008), Australia (Gurba and Weber, 2001;Golab and Carr, 2004;Golab et al, 2007;Wold et al, 2008), China, Vietnam, Botswana, Uganda, and South Africa. These intrusions are a result of post-depositional volcanism into the rift basins (e.g., Gudmundsson and Loetveit, 2005) and coal seams (e.g., Saghafi et al, 2008). The physical behavior of the dyke material is extremely variable.…”

“…Based on recent geologic studies of gas emission sites, geologic structures have been identified as a major factor in the occurrence of gas emission (Saghafi et al, 2008). Thrusts, strike-slip faults, normal faults, igneous intrusions, and recumbent fold hinges, which are referred to as 'tectonic disturbances,' are related to highlyfractured coal and thought to cause gas emission hazards (Shepherd et al, 1981;Saghafi et al, 2008). Anomalous stress and gas conditions seem to exist in and around these geologic structures.…”

“…Various aspects of minerelated stresses, gases and geologic structures have been examined in a worldwide review of the problem of gas emission in coal mines (e.g., Shepherd et al, 1981;Zhang, 1986;Shen and Stephansson, 1994;Lunarzewski et al, 1996;Clayton,1998;Lunarzewski,1998;Noack, 1998;Bibler et al, 1998;Zhi et al, 2007;Jia et al, 2007;Karacan et al, 2008;Islam et al, 2009). Based on recent geologic studies of gas emission sites, geologic structures have been identified as a major factor in the occurrence of gas emission (Saghafi et al, 2008). Thrusts, strike-slip faults, normal faults, igneous intrusions, and recumbent fold hinges, which are referred to as 'tectonic disturbances,' are related to highlyfractured coal and thought to cause gas emission hazards (Shepherd et al, 1981;Saghafi et al, 2008).…”