Mine transient electromagnetic prospecting method for improving detection accuracy by shielding metal interference

Abstract

The application discloses a mine transient electromagnetic exploration method for shielding metal interference and improving detection accuracy, and comprises the following steps: S1, setting a measuring point at a chamber of an upper and lower gate of a working face; S2, moving a measuring device to the measuring point for detection; arranging an anti-metal interference shielding device at the measuring point during detection, so that the anti-metal interference shielding device is coated behind a measuring coil of the measuring device to shield metal interference; the anti-metal interference shielding device is a concave plate structure, comprising an inner concave surface and an outer edge surface surrounding an outer periphery of the inner concave surface; the anti-metal interference shielding device comprises an inner layer, an outer layer of conductive material layer and a non-conductive material layer between the inner and outer layers; S3, after the arrangement is completed, detection of the measuring point is completed according to a set detection angle; S4, moving the measuring device and the anti-metal interference shielding device to a next measuring point, completing operation and completing the whole detection work in the same way.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mine water disaster prevention, and particularly relates to a mine transient electromagnetic exploration method for shielding metal interference and improving detection accuracy. BACKGROUND

[0002] The mine transient electromagnetic method has strong detection directionality, long detection distance, sensitivity to water-bearing bodies, rapid construction and flexible arrangement, and can detect the internal and external water-rich conditions of the working face, which is superior to other geophysical methods. However, with the development of mine mechanization, intelligentization and informationization and the change of support forms in recent years, a large number of metal bodies and electronic and electrical equipment exist in the mining working face, which brings serious interference to the transient electromagnetic detection environment and easily causes false anomalies.

[0003] When the working face is detected by the mine transient electromagnetic exploration, point-by-point scanning detection is usually used. This detection process cannot avoid the influence of surrounding metals on detection, and can only eliminate the influence by filtering during post-processing. This method cannot truly eliminate metal interference, and the apparent resistivity curve obtained by processing often shows a strip-shaped distribution and produces many false anomalies, which reduces the detection accuracy and seriously restricts the development of the mine transient electromagnetic method.

[0004] Therefore, the present application provides a mine transient electromagnetic exploration method for shielding metal interference and improving detection accuracy to solve the problems in the prior art, which is a problem that needs to be solved by those skilled in the art. SUMMARY

[0005] The present application aims to solve the above problems, and provides a mine transient electromagnetic exploration method for shielding metal interference and improving detection accuracy, which can shield the interference of metal interference on mine transient electromagnetic exploration and completely solve the problems of false anomalies and low accuracy in mine transient electromagnetic exploration.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0007] A mine transient electromagnetic exploration method for shielding metal interference and improving detection accuracy, comprising the following steps:

[0008] S1, setting a measurement point at the chamber of the upper and lower gateways of the working face or the chamber of the upper and lower gateways and the cut, and removing movable metal bodies near the measurement point;

[0009] S2, moving the measuring device to the measurement point for detection, and arranging an anti-metal interference shielding device at the measurement point during detection, so that the anti-metal interference shielding device is wrapped behind the outgoing electromagnetic wave of the measuring coil of the measuring device to shield metal interference;

[0010] The anti-metal interference shielding device is a concave plate structure, comprising a concave surface, an outer edge surface surrounding the outer periphery of the concave surface, and in a cross section; the anti-metal interference shielding device comprises an inner layer, an outer layer of conductive material layer and a non-conductive material layer between the inner and outer layers.

[0011] S3, after the arrangement is completed, the detection of the measurement point is completed according to the set detection angle;

[0012] S4, the measuring device and the anti-metal interference shielding device are moved to the next measurement point, the operation is completed and the whole detection work is completed by analogy.

[0013] As an improvement to the above technical solution, the concave surface of the anti-metal interference shielding device is adapted to the shape of the measuring coil; specifically, the concave surface includes a rectangle, a circle, but is not limited to a rectangle and a circle.

[0014] As an improvement to the above technical solution, the gap between the concave surface of the anti-metal interference shielding device and the measuring coil is 0.1m.

[0015] As an improvement to the above technical solution, when the working face width is <180m, the measurement points are arranged in the chamber of the upper and lower crossheading of the working face, and when the working face width is >180m, the measurement points are arranged in the chamber of the upper and lower crossheading and the cut of the working face.

[0016] As an improvement to the above technical solution, the thickness of the conductive material layer of the inner layer is 2mm, the thickness of the conductive material layer of the outer layer is 2mm, and the thickness of the non-conductive material layer is 3cm.

[0017] As an improvement to the above technical solution, the conductive material is a stainless steel plate, and the non-conductive material is a polystyrene plate.

[0018] As an improvement to the above technical solution, the distance between two adjacent measurement points is ≤70m.

[0019] As an improvement to the above technical solution, each measurement point comprises a plurality of detection positions, and each detection position comprises a plurality of detection angles.

[0020] As an improvement to the above technical solution, the included angle between adjacent detection positions in the horizontal plane is 15 degrees; the detection angle of each detection position is an inner slope angle of 45°, an inner slope angle of 60°, an inner slope angle of 75°, a floor angle of 90°, and an outer slope angle of 70°.

[0021] Compared with the prior art, the present application has the advantages and positive effects of:

[0022] The application adopts the fixed-point scanning cross detection and the anti-metal interference shielding device to realize the internal and external cross repeated detection of the working face, increase the data coverage times, increase the data amount, reduce the blank area of the detection, shield the interference of the downhole metal on the transient electromagnetic detection well, and the operation is simple and the detection effect is good. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor under the premise of the drawings.

[0024] Figure 1 is the measuring point layout of the present application;

[0025] Figure 2 is the data point distribution diagram of the present application;

[0026] Figure 3 is the fixed-point scanning cross detection plane schematic diagram of the present application;

[0027] Figure 4 is the fixed-point scanning cross detection profile schematic diagram of the present application;

[0028] Figure 5 is the overall structure schematic diagram of the anti-metal interference shielding device of the present application;

[0029] Figure 6 is the side sectional view structure schematic diagram of the anti-metal interference shielding device of the present application. EMBODIMENT

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, any modification, equivalent replacement, improvement, etc. obtained by those skilled in the art without creative labor should be included in the protection scope of the present application.

[0031] As shown in Figures 1-6 The mine transient electromagnetic exploration method for shielding metal interference and improving detection accuracy of the present application comprises the following steps:

[0032] S1, according to the coal seam inclination of the working face, the buried depth of the aquifer, the width of the working face, and the detection purpose and other factors, the detection angle and the detection direction are set. The set detection angle and detection direction should cover the outside and inside of the working face;

[0033] S2, arranging the position of the measuring point and the interval of the measuring point according to the width of the working face and the set detection angle;

[0034] S3, the measuring point should be selected in the chamber or the roadway, and the movable metal body near the measuring point should be removed before the measuring point in the roadway is detected;

[0035] S4, the anti-metal interference shielding device is installed behind the detection coil during on-site detection, which is used to shield the metal interference near the detection position, and then the detection is completed according to the designed detection angle and detection direction.

[0036] S5, after the detection of the first measuring point is completed, the detection equipment is moved to the next measuring point to repeat the operation of the previous measuring point, and so on to complete the detection of the whole working face.

[0037] Optionally, the measuring point is arranged in the chamber or the relatively empty section of the upper and lower crossheading and the cut of the working face, and the position of the measuring point should also be determined according to the width of the working face. When the width of the working face is less than 180m, the measuring point is arranged in the upper and lower crossheading of the working face, and when the width of the working face is greater than 180m, the measuring point is arranged in the upper and lower crossheading and the cut of the working face.

[0038] Optionally, the interval of the measuring point arrangement should consider the detection capability of the mine transient electromagnetic instrument, and the interval between the adjacent two measuring points should be less than or equal to 70m.

[0039] Optionally, the measurement angle should be determined according to the coal seam inclination in the working face, and the set angle should cover the whole working face and the periphery.

[0040] Optionally, the anti-metal interference shielding device is installed behind the detection coil before detection to shield the metal interference near the detection position.

[0041] Optionally, according to different detection angles, the fan-shaped range of 0°-180° is formed on the fixed measuring point, and multiple measurement angles are sequentially scanned and detected every 15°, so as to form a fan-shaped coverage in and out of the working face.

[0042] In the use of the present application: taking a certain mining face as an example, the face is 500 m long in strike, 120 m wide in inclination, the coal seam inclination is 7°, the water bearing property of the rock stratum under the floor of the No. 2 coal seam is found out, the water rich and poor areas of the rock stratum are divided, the water threat in mining of the face is analyzed, and the mine transient electromagnetic exploration method of shielding metal interference to improve the detection accuracy is used for detection; according to the geophysical purpose, the hydrogeological conditions of the geophysical area, and considering the detection ability of the instrument and the coal seam inclination, the principle of "geophysical exploration covering the whole face interior and periphery" is followed to design five directions of 45°, 60°, 75° of the inner slope dip angle, 90° of the floor dip angle, and 70° of the outer slope dip angle for scanning detection; seven detection points are arranged in the upper and lower crossheading of the face, and the point spacing is 70 m.

[0043] After reaching the detection point, the anti-metal interference shielding device is first installed on the measuring coil, the anti-metal interference shielding device is composed of three layers of materials, the first layer 1 is a 2 mm stainless steel plate formed at one time, the middle layer 2 is a 3 cm polystyrene material, and the outermost layer 3 is a 1 mm stainless steel plate formed at one time, and attention is paid to leaving a 0.1 m gap between the measuring coil and the metal interference shielding device and the measuring coil.

[0044] As shown in Figure 3 and 4 , after the anti-metal interference shielding device is installed, the inclination is adjusted to the first detection angle of 45° of the inner slope dip angle, as shown in Figure 4 ①, facing the face direction, the left side of the parallel roadway direction is 0°, and in the 0°-180° sector range, 13 directions are detected at an interval of 15°, the measurement of the first detection angle is completed, and then the inclination is adjusted to the second detection angle of 60° of the inner slope dip angle, as shown in Figure 4 ②, the detection is carried out according to the first detection angle method to complete the detection of the second detection angle, and the five angles of the first detection point are detected in turn, and the following angles are shown in Figure 4 ③, ④, ⑤, and the detection of all detection points is further completed according to the method of the first detection point.

[0045] After the detection of all angles of the first detection point is completed, the detection equipment is moved to the next detection point to repeat the operation of the previous detection point, and the detection of the whole face is completed in this way.

[0046] As shown in Figure 5 and 6As shown, the anti-metal interference shielding device of the present application is a concave plate structure, the shape of the concave surface is adapted to the shape of the measuring coil, for example, when the measuring coil is rectangular, the concave surface is rectangular, when the measuring coil is circular, the concave surface is circular. Adaptation means that the concave surface is equal to or slightly larger than the maximum diameter of the measuring coil. Of course, two common cases of the anti-metal interference shielding device are described here, but when the measuring coil is of other shapes, the concave surface of the anti-metal interference shielding device is preferably adapted to it to have the best anti-metal interference effect. The outer edge surface surrounds the concave surface and is inclined to the coil direction to form a half-enclosed structure, so that the rear of the measuring coil is completely shielded, avoiding metal interference with the measurement of the measuring coil, and the front of the measuring coil is not shielded, without affecting the measurement of the measuring device. Figure 6 1 is the inner layer of stainless steel plate, 2 is the middle layer of polystyrene plate, and 3 is the outer layer of stainless steel plate.

Claims

1. A transient electromagnetic exploration method for mines that shields against metallic interference and improves detection accuracy, characterized in that: It comprises the following steps: S1, setting measuring points at the chamber of the upper and lower gateways of the working face or the chamber of the upper and lower gateways and the cut of the working face, and removing movable metal bodies near the measuring points; S2, moving the measuring device to the measuring points for detection, arranging the anti-metal interference shielding device at the measuring points during detection, and shielding metal interference by covering the measuring coil of the measuring device behind the outgoing electromagnetic waves of the anti-metal interference shielding device; The anti-metal interference shielding device is a concave plate structure, comprising an inner concave surface and an outer edge surface surrounding the outer periphery of the inner concave surface, and in the cross section; the anti-metal interference shielding device comprises an inner layer, an outer layer of conductive material layer and a non-conductive material layer between the inner and outer layers; S3, after the arrangement is completed, the detection of the measuring point is completed according to the set detection angle; S4, moving the measuring device and the anti-metal interference shielding device to the next measuring point, completing the operation and completing the entire detection work in the same way; When the width of the working face is less than 180m, the measuring points are arranged at the chamber of the upper and lower gateways of the working face, and when the width of the working face is greater than 180m, the measuring points are arranged at the chamber of the upper and lower gateways and the cut of the working face; Each measuring point comprises a plurality of detection positions, and each detection position comprises a plurality of detection angles; The included angle between adjacent detection positions in the horizontal plane is 15 degrees; the detection angles of each detection position are 45°, 60°, 75° of the inner slope, 90° of the floor and 70° of the outer slope.

2. The method of claim 1, wherein: The inner concave surface of the anti-metal interference shielding device is adapted to the shape of the measuring coil.

3. The method of claim 1, wherein: the mine transient electromagnetic surveying method is a transient electromagnetic method (TEM) surveying method. The gap between the inner concave surface of the anti-metal interference shielding device and the measuring coil is 0.1m.

4. The method of claim 1, wherein: the mine transient electromagnetic surveying method is a transient electromagnetic method (TEM) surveying method. The thickness of the inner layer of conductive material layer is 2mm, the thickness of the outer layer of conductive material layer is 1mm, and the thickness of the non-conductive material layer is 3cm.

5. The transient electromagnetic exploration method for mines as described in claim 4, characterized in that: The conductive material is stainless steel plate, and the non-conductive material is polystyrene plate.

6. The method of claim 1, wherein: the mine transient electromagnetic surveying method is a transient electromagnetic method (TEM) surveying method. The distance between two adjacent measuring points is less than or equal to 70m.

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