Improving coal quality estimation through multiple geophysical log analysis

Applications of Geophysical Logs to Coal Mining—Some Illustrative Examples

“…The merits of coal quality parameter estimations using multiple geophysical logs have been demonstrated by Zhou and Esterle [37] and Zhou and O'Brien [7]. Here we will use another example from a mine in New South Wales, Australia, to illustrate the method's performance.…”

“…In these logs, GRDE and GRNP are gamma ray logs from density and neutron loggings, respectively, reflecting the lithology of the coal; DENB and DENL are shortand long-spaced density logs, which have strong correlation with coal ash content; DEPO and RPOR are sandstone-calibrated porosities derived from density and neutron logs; and MC2F and MC4F are 20 cm-spaced and 40 cm-spaced sonic logs, signifying the integrity and the strength of the coal samples. The merits of coal quality parameter estimations using multiple geophysical logs have been demonstrated by Zhou and Esterle [37] and Zhou and O'Brien [7]. Here we will use another example from a mine in New South Wales, Australia, to illustrate the method's performance.…”

“…As illustrated above, geophysical borehole logging measurements can be used for coal seam identification and correlation and geotechnical rock mass characterisation. They can also be used for specific coal-quality assessment [6,7,[34][35][36][37][38][39]. Zhou and Esterle [37] also investigated ways to improve the coal density and quality estimation from geophysical logs.…”

“…Geophysical borehole logging, which consists of measuring various in-situ petrophysical parameters such as the acoustic, radiometric and electric properties of the rocks down boreholes, is carried out routinely at coal mines. The logs provide a rich source of rock property information and can be used for qualitative interpretation such as picking coal seams from density log and strata correlation [1][2][3], in addition to litho-stratigraphic interpretation [4,5], orebody delineation and grade estimation [6,7] and geotechnical and rock mass characterization [8][9][10][11][12][13][14][15].…”

Analysis of well logs for the detection of coal seams - A case study from Rajbar block of Auranga coalfield, Jharkhand, India

“…The conventional well-logs such as density, gamma-ray, single point resistance and resistivity are in vogue for identification of coal seams, variation of their thickness and also lateral correlations. Apart from detection, the parameters that describe the quality of coal such as ash content, volatile matter, specific energy, presence of radioactive minerals (such as pyrite) in coal in addition to economic and engineering parameters, can also be predicted with the combination of sonic, neutron porosity and induced polarization logs (Kowalski and Fertl, 1976;Ghosh, 2016;Zhou et al, 2016). Besides, Caliper log is also used to know the borehole rugosity, which affects the readings recorded by other logs.…”