LOCATION OF DAMAGE ZONES IN COAL SEAMS BY UNDERGROUND RESISTIVITY PROSPECTING

The distributed point source method (DPSM) can be used to locate secondary charges induced at interfaces of media with different conduction in rock masses. The method allows delineating zones of low-amplitude discontinuity by the data of underground resistivity prospecting. DPSM is based on the fundamental solution of the Laplace equation. By electrical measurements, a system of linear equations is built; the number of the equations is governed by the number of measurement points in the electrical survey line, which limits the location domain of secondary charges. The location domain is selected based on the assumption of adjacency to the maximum anomalous signal which is determined as a difference of measured potentials on the electrical survey lines in the damaged and intact rock mass. A low-amplitude discontinuity changes resistance at the coal–enclosing rock interface; thus, it is assumable that the secondary charges locate in the plane of seam. For the obtained electrical data, a system of equations is constructed. The correct solution of the system is possible if the minimum distance R between the measurement point and the calculation domain in nonzero. The system solution provides values of secondary charges the coordinates of which are pegged to centers of cells in the meshed calculation domain. The number of cells equals the number of equations in the system. The calculated data are compared with a certain threshold and the lower values are nulled, which allows a more distinct delineation of the anomalous zone. Using DPSM together with the analytical extension method improves efficiency and reliability of resistivity section of a test area in coal seam. The analytical extension method determines the anomalous zone center and, thus, the calculation domain location, while DPSM delineates the latter domain. All calculations are performed in MatLab.


For citation: Gaysin R.M., Tsarikov A.Yu. Location of damage zones in coal seams by underground resistivity prospecting. MIAB. Mining Inf. Anal. Bull. 2019;(6):19-26. [In Russ]. DOI: 10.25018/0236-1493-2019-06-0-19-26.

Keywords

Low-amplitude tectonic discontinuity, distributed point source method, fundamental solution of the Laplace equation, underground resistivity prospecting, equatorial dipole electric sounding, analytical extension method, continued fractions, Matlab.

Issue number: 6
Year: 2019
ISBN: 0236-1493
UDK: 550.837.31
DOI: 10.25018/0236-1493-2019-06-0-19-26
Authors: Gaysin R. M., Tsarikov A. Yu.

About authors: R.M. Gaysin, Cand. Sci. (Eng.), Assistant Professor, e-mail: rmgaisin@mail.ru, A.Yu. Tsarikov, Graduate Student, e-mail: zarikov92@mail.ru, National University of Science and Technology «MISiS», 119049, Moscow, Russia. Corresponding author: R.M. Gaysin, e-mail: rmgaisin@mail.ru.

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