Geoelectric Determination of Quality Changes and Tectonic Disturbances in Coal Deposits*

Abstract

A new underground geoelectric method is presented for the determination of small tectonic disturbances and barrenings in coal seams. The distribution of the apparent resistivity can be mapped from the measured apparent resistance data by using a recently developed geoelectric imaging method. The applicability of the methods are proved by in situ measurements and by a model experiment. IN-SEAM GEOELECTRIC METHODSTwo new methods called ' geoelectric seam-sounding and transillumination ' allow the determination of tectonic and stratigraphic disturbances of coal beds. Both are

Parameter Estimation and Fault Detection by Three‐component Seismic and Geoelectrical Surveys in a Coal Mine*

“…The recorded current and potential values of the geoelectrical survey were converted to apparent resistivity curves, taking into account the electrode configurations (Csokas et al 1986a). Figure 4 shows the traveltime-reduced seismogram sections recorded on the y-and z-components of the upper and lower geophone-triplet.…”

“…For the geoelectrical survey, seam-and drift-soundings (Csokas 1974;Gyulai 1979;Csokas et al 1986a;Csokas et al 1986b) were executed.…”

“…Geoelectrical in-mine surveys were theoretically developed and brought into practice in Hungarian coal mines. Csokas (1974), Gyulai (1979Gyulai ( , 1982, Csokas, Dobroka and Gyulai (1986a) and Csokas, Dobroka, Gyulai and Ormos (1986b) published both an outline of the method for the determination of the in situ apparent resistivities and of seam obstructions and numerical calculations of sounding curves for the interpretation of geoelectrical in-mine measurements. However, an effective combination of seismic and geoelectrical in-mine investigations has not previously been achieved.…”

“…To meet these objectives underground VSP and an in-seam seismic amplitudedepth distribution and transmission survey were carried out, using body waves for the first survey and channel waves for the latter two surveys. For the geoelectrical survey, seam-and drift-soundings (Csokas 1974;Gyulai 1979;Csokas et al 1986a;Csokas et al 1986b) were executed.…”

Study on the detection technology of DC penetration in coal mine

“…At present, mining DC penetration electrode arrangement and observation methods tends to approached perfection (Gyulai et al,2013;Sasaki et al,1993;Takacs,2012;Csokas et al,1986), however, due to the lack of research on electric field distribution and the relationship between response characteristics of electrical penetration curve and spatial location of anomalous body, lead to the existing data processing and interpretation methods are single and lack of accuracy. The author deduce the electrical penetration potential equation of measuring point in point-source current field from the case study of conductive sphere, aiming at typical groundwater inrush models of fractured zone on working face floor , using 3-D finite element method for numerical simulation, analyzed and summarized the relationship be-tween response characteristics of electrical penetration curve and spatial location of anomalous body, and try to use 3-D resistivity inversion for electrical penetration data processing and interpretation, dis-cussed the feasibility of effective exploration depth of electrical penetration detection technology and the method of data processing and interpretation of the combination based on 3-D resistivity inversion and electrical penetration curve.…”