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

Abstract

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.

Integrated geophysical approach for Coal mine fire in Jharia coalfield, India

“…This collected data are adjusted according to the International Geomagnetic Reference Field (IGRF) in Geosoft Oasis Montaj. Further, reduced to North Magnetic Pole (RTP) anomaly map has been generated in Geosoft for removal of lateral shifts and asymmetries caused by the local orientation of the magnetic anomaly Pal et al 2016Pal et al , 2017. The RTP anomaly map and its residual anomaly map are shown in Fig.5a and 5b.…”

“…They established it from the thermal band of Landsat ETM+ data and in-situ temperature observations using thermal imaging camera. Further, in recent years geophysical studies, mainly, magnetic (Vaish and Pal 2013Kumar et al 2015;Pal et al 2016Pal et al , 2017 , SP (Bharti et al 2014;Singh et. , 2019Srivardhan et al 2016, Mishra et al 2018Kumar and Pal 2020;Srivardhan et al, 2016) and electrical resistivity (Gangopadhyay 2003;Pal et al 2016;Mishra et al 2018) have been carried out to map coal re in the Jharia coal eld and surroundings.…”

Aeromagnetic mapping of fault architecture along Lagos–Ore axis, southwestern Nigeria

“…It also smoothens the residual data by alternating highfrequency or short wavelength anomalies relative to their opposite signatures [68,77]. This technique can be adopted in place of low-pass and high-pass filters [78]. The advantages of continuation technique over low pass and high pass include the following: prominent reduction and separation of near surface (shallow) effects over the deeper ones [68]; its use in the estimation of depth to magnetic sources; and it retains the signatures of the geopotential field anomaly, provided that the continuation does not intrude into the top of the magnetic body [79].…”

“…However, the computation of upward continuation (UC) is stable at higher heights, which accounts for contributions from various sources. The stability of UC and horizontal derivative has made them to be included in computation of downward continuation model [78] using the Taylor's series as presented in equation 2. where T(x, y, h) = potential field at the level of h, T (x, y, 0) = original potential field data, m = mth-order vertical derivative of the potential field, and h = continuation height.…”

“…At higher order, the vertical derivatives become unstable, which can influence the noise effects [82]. Therefore, the Taylor's series, especially equation 3is limited to order 3 [78]. The algorithm used in the two continuations (upward and downward) has been presented by [75].…”