• Abhay Kumar Bharti

Articles written in Journal of Earth System Science

• Coal fire mapping of East Basuria Colliery, Jharia coalfield using vertical derivative technique of magnetic data

The present study deals with the coal fire mapping of East Basuria Colliery, Jharia coalfield, India, using the magnetic method. It is based on the fact that rise in temperature would result significant changes in magnetic susceptibility and thermo-remanent magnetization (TRM) of the overlying rocks. Magnetism increases slowly with the rise of temperature until the Curie temperature. Generally, rock/overburden loses magnetization and becomes paramagnetic due to heating to Curie temperature, which results with significant reduction in magnetic susceptibility. However, magnetism increases significantly after cooling below the Curie temperature. Several data processing methods such as diurnal correction, reduction to pole (RTP), first and second vertical derivatives have been used for analysis of magnetic data and their interpretation. It is observed that the total magnetic field intensity anomaly of the area varies approximately from 44850 to 47460 nT and the residual magnetic anomaly varies approximately from −1323 to 1253 nT. The range of the magnetic anomaly after RTP is approximately 1050–1450 nT. About 20 low magnetic anomaly zones have been identified associated with active coal fire regions and 11 high magnetic anomaly zones have been identified associated with non-coal fire regions using vertical derivative techniques.

• Downward continuation and tilt derivative of magnetic data for delineation of concealed coal fire in East Basuria Colliery, Jharia coal field, India

The present study deals with the characterization of subsurface coal fires of East Basuria colliery in Jharia coal field, India using tilt derivative and downward continuation of magnetic data. Magnetic data processing methods such as diurnal correction, noise removal, reduction to pole, tilt derivative and downward continuation have been used to process the data and for the interpretation of results on the basis of magnetic properties of overlying materials which change with the temperature variation above or below the Curie temperature. Most of the magnetic anomalies are associated with coal fire and non-coal fire regions which are correlated with tilt-derivative anomaly and corresponding downward-continued anomaly at different depths. The subsequent surface and subsurface characteristics are explained with good agreement. Approximate source depth of principal anomaly inferred from tilt derivatives method are corroborated with multi-seam occurrences, mine working levels and surface manifestation which are also correlated well with 3D model of downward continued anomaly distribution.

• Groundwater prospecting by the inversion of cumulative data of Wenner–Schlumberger and dipole–dipole arrays: A case study at Turamdih, Jharkhand, India

The present study deals with groundwater prospecting in hardrock terrain. Initially, the Wenner–Schlumberger array and the dipole–dipole array data have been acquired using Syscal Junior Switch-48. Furthermore, data acquired using both arrays have been merged using Prosys-II data handling software for the inversion of the cumulative data for possible mapping of water-bearing fracture rock masses with different structural distribution in a complex geological environment. The data have been analysed using RES2DINV software, based on the smoothness constrained least-square technique. Two numbers of 2D electrical resistivity tomography profiles (AA$^{\prime}$ and BB$^{\prime}$) have been selected over an official colony of the Turamdih uranium mine for groundwater prospecting, which is located at about 24 km west of Jaduguda, Jharkhand, India. High-resistivity features associated with a dyke-like structure have been delineated in both the profiles. Three low-resistivity features have been delineated as water saturated alluvium/aquifers in profile AA$^{\prime}$. A low-resistivity feature associated with the water-saturated fracture zone has been identified in profile BB$^{\prime}$, which is well correlated with the surficial location of an ephemeral channel at the bottom of the hill across the slope. It is observed that geoelectric sections generated by the inversion of cumulative data of both arrays provide superior results compared with the Wenner–Schlumberger and dipole–dipole arrays, separately.

• Detection of subsurface cavity due to old mine workings using electrical resistivity tomography: A case study

The present study deals with the detection of underground concealed voids/cavities/galleries in Chinchuria railway station, Raniganjh coalfield in India for ground stabilization using electrical resistivity tomography (ERT) technique. Initially, numerical analysis of ERT data was carried out using Wenner–Schlumberger and dipole–dipole array configurations corrupted by 5–10% Gaussian random noise for better understanding of real field conditions. The two types of voids, i.e., water and air, filled in old mine workings were simulated accordingly in the forward model. The dipole–dipole array provides superior results compared to Wenner–Schlumberger array. Considerable accuracy of voids/cavities/ galleries dimension could be acquired from dipole–dipole array. In Beld, two number of ERT profiles (Profile-AA' and Profile-BB') were conducted over the study area using said configurations. The data was acquired using Syscal-Pro resistivity imaging system with 96 electrodes and the data processing was carried out using the tomographic inversion software RES2DINV to analyse true resistivity based on the robust or blocky regularization inversion technique (L$_1$-norm). High resistivity contrast with backgrounds in the occurrence of possible old mine workings consisting of hard rock and alternative coal pillars interconnected cavities and mining galleries was identified. Considering the indirect approach of ERT method, a borehole was being drilled along the profile-AA' of dipole–dipole array, drilling and resistivity results indicated the presence of air-filled cavity associated with old mine workings. Hence, it is concluded that the technique used in this study is useful in increasing the technical merit of electrical resistivity interpretation for old mine workings areas.

• # Journal of Earth System Science

Volume 131, 2022
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019