高分辨率大地电阻率法探测废弃煤矿巷道外文文献翻译、中英文翻译

英文原文Detecting Abandoned Coal Mine Entries by High Resolution Earth Resistivity MethodXianxin Shi, ProfessorShu Yan, ProfessorMingsheng Shen, ProfessorXian Branch, CCRI (China Coal Research Institute) Xian, Shaanxi, ChinaABSTRACTIn surface electrical exploration the high resolution earth resistivity method (HRRM) is a very effective method for detecting abandoned drift mines workings. When the abandoned mines are more than 500 ft (150 m) deep, its detection capability reduces greatly and requires more effort to implement. In Yan Quan coal mine, Shanxi province, we tried to adapt this method for underground application. Two survey lines were designed with the spacing of current and potential poles 20 m and 10 m, respectively and measuring points at 2m. The measurement radius of I line and II line were 140 m and 60 m, respectively, and the infinitely far pole was 12002000 m from the survey line. (Note the I and II lines are located on the north and south ribs of main tunnel, respectively). The survey results showed that abandoned workings were located at 25-70m, Survey Line I and at 80-110m, Survey line II. Based on this finding, the longwall panel gateroads and set up entry were properly located thereby providing safe mining of the No. 15 Coal seam.Key Words: Abandoned coal mine, High resolution earth resistivity, Underground electrical explorationINTRODUCTIONThe development of roadways for the 9th mining district for the #15 coal seam, Nanzhuang Coal Group Co Ltd, Yangquan, Shanxi Province are approaching the Hougou abandoned gobs. Since the data regarding the extent and condition of Hougou gobs were not reliable, it is difficult to finalize the panel layout for the #15 coal seam. In order to provide sufficient geological data for rational layout and safe development of mains and setup entry, the Hougou gob conditions (i.e. area and location) must be known clearly first.Based on our experience gained in the past 10 years, when coal seam is less than 150 m deep, the high resolution surface resistivity method can produce better results. But the Hougou abandoned mine gobs were 350 m deep. For this reason, we tried to use the high resolution resistivity method underground to detect the gobs from entry ribs to facilitate the development of #15 coal seam.CHARACTERISTICS OF EARTH RESISTIVITYThe #15 coal is the major coal seam in the reserve. Seam thickness is 5.25-6.63 m averaging 5.89 m and consistent throughout the whole reserve. It is anthracite with low-medium ash, very low-low sulphur and high heating value. Its electric resistivity is relatively low. After mining, if the gob is not flooded with water, its apparent resistivity will increase significantly and behave as a high-resistivity material regardless whether the gob is caved or not. This is the prerequisite of physical property for the application of high resolution resistivity method.UNDERGROUND HIGH-RESOLUTION RESISTIVITY METHODAs mentioned above, good seam quality is the prerequisite for high resolution resistivity method. But what devices are needed to perform the resistivity exploration deserves further study. Due to the fact that a gob is a man-made isolated geological body and its not uniform as a bedded deposit, special devices that can superimpose its electric information and focus on its location such that it can distinguish it from the surrounding rocks, must be used to detect this type of geological body.The underground high resolution resistivity method employs special three-pole devices, i.e. monopole-dipole device densely dispatched that can increase the level of observation and control, add the number of superposition, enlarge the amount of information, and improve the resolution of gob detection so that the gobs can be identified from the surrounding rocks. Figure 1 shows the array of survey stations.The parameters adopted for the underground earth resistivity method are:1.Distance between power supply stations, A and A: 20 m2.Distance between survey stations, C and C: 2 m3.Distance between poles, MN: 10 m4.Radius of survey lines: Line I 140 m, Line II 60 m5.Location of infinite distance pole: 1,200 2,000 m from the lines.Figure 1 Survey array for underground earth resistivity methodUnderground survey data were collected by flameproof microvolt digital direct current resistivity meter. In underground survey, the power supply station was located at 20 m interval. For every power supply station, the voltage difference between both directions of measurements must be recorded. The maximum distance of MN on both sides of each power supply was 140 m, i.e. the maximum offset distance was 140 m. This way double coverage observation can be realized and the exploration area can cover up to 140 m.In order to insure the accuracy of the data obtained underground, the following measures were adopted:1.In order to insure the power supply was well-grounded, a horizontal hole in the coal seam was drilled at its designated location. Mud and salt water were added. After insertion of the pole, the hole was tamped tight.2.The bronze pole must be inserted sufficiently deep, reaching wet spots, and be tamped tight in order to insure data obtained were steady and reliable.3.Batteries were changed frequently to insure the voltage of power supply was steady and current was sufficient. This is the key to insure the accuracy of the data obtained.4.During the course of survey, always check if the location of the power supply was accurate and data obtained were steady. Once abnormal conditions were observed, the pole location must be re-confirmed, additional poles added, and measurements repeated until the errors obtained were within the limits allowed by regulations.Due to the fact that the instrument employed was steady and precise. So with proper handling of the poles, the ground resistance was greatly reduced. As a result, the signal was stronger and the accuracy of data increased. During the course of survey measurement, the pole of MN was re-confirmed frequently. If abnormal data appeared, observations were repeated. This way the accuracy and reliability of the collected data were insured. DATA ANALYSISThe high resolution resistivity survey was performed along the survey lines simultaneously for measurements in cross-section and depth. Data analyses were divided into two steps: First, check the voltage difference at every supply pole and see if it decreases gradually with distance away from the pole. If there is an abrupt change, it must be analyzed why so? Then the results are computed and a cross section map of apparent resistivity drawn.Since the small abandoned gobs in this mining district had little water, the cross section map of apparent resistivity should be one that exhibits an obvious high resistivity. In this map, if the rate of change is uniform and steady, it reflects the nature state of the rock strata; But if there are local abnormal changes or inconsistent changes, especially where random changes occur, it represents the existence of gobs. Because voids and fractures resulting from mining-induced stresses interrupt the intrinsic regular rhythm of coal measures strata and increase the resistivity.Figures 2 and 3 are the cross-section apparent resistivity contour maps for Line I and II, respectively. Please note the unit of the vertical and horizontal axes is meter while the intensity of shade denotes resistivity intensity with darker being higher.Figure 2 Apparent resistivity along Survey Line I, 8905 entry, Nan Zhuang Coal Group Figure 3 Apparent resistivity along Survey Line II, 8905 entry, Nan Zhuang Coal GroupIn Figure 1 the area between 25-70 m horizontally and 110-130 m vertically (or deep) and in Figure 2 that between 80-100 m horizontally and 30-50 m vertically (or deep) show obvious abnormal changes in apparent resistivity. They are darker indicating higher resistivity. This is in conflict with the intrinsic regular rhythm of physical property for the coal measures strata in their nature state. They were the results of abandoned gobs!Based on the survey results, mine management drilled in-seam horizontal holes from the entry rib at 50 m location on Line I. When it reached 120.4 m from the rib, coal was soft without resistance and drilling water was completely lost. In addition, methane came out with smell of rotten-eggs. Accordingly it was determined this was the gob of a small abandoned coal mine, approximately 15 m wide. Therefore the survey results were validated. Based on the survey results, mine management selected the proper location of mains and set-up entry and the safe mining operations of #15 coal seam were insured.REFERENCES1Fitch, A.A. Development in Geophysical Exploration Methods-5, Applied Science Publishers, London and New York, 1983. 2Yan, S., and M. Chen. Detecting Underground Openings by High Resolution Resistivity Method. Geology Press, Beijing, 1996.3Shi, X., M. Chen et al. Report on Resistivity Exploration of #15 Coal Seam 9th Mining District, Nan Zhuang Coal Group, Yangquan, Xian Province, Xian Branch of CCRI, 2004.中文译文高分辨率大地电阻率法探测废弃煤矿巷道石先新，晏殊，沈明申（中国煤炭科学研究院西安分院）摘 要：在表面荷电勘探中，高分辨率大地电阻率法是勘探废巷十分有效的方法。但是当废弃煤矿的深度高达500英尺（150m）时，该方法的探测能力很大程度的降低，需要采取更多的措施来进行探测。我们在山西省阳泉煤矿使用此种方法进行地下勘探。探测过程使用两条测线，分别设置20m的极间距和10m的极间距，同时在两m处设置检测点。第条线的检测变径为140m，第条线的为60m，而极远处的极点大概离测线12002000m。（注意：、分别位于掘进大巷处）。试验结果表明：测线的废弃工作面在2570m，测线的工作面在80110m。通过试验结果，对入口进行适当的定位，从而对15号煤层提供了安全的采掘环境。关键词：废弃煤巷 高分辨率大地电阻率法 井下电法勘探1引言 山西省阳泉南庄煤炭集团有限公司的15煤层的9号采区的巷道的推进是靠近后沟废弃采空区的。由于关于后沟采空区的条件和采掘程度数据的可靠性较低，这给15号煤层面板布局的最终确定带来了困难。为了给井巷的合理布局、设置安全入口以及主巷道的发展安全提供可靠性地质资料，后沟采空区的情况必须清楚明了。根据我们过去十年获得的经验，如果煤层的厚度小于150m，高分辨率的表面电阻率法则可以得到更加精确的结果。然而，后沟废弃采空区的煤层厚底却达到了350m。考虑到此种情况，我们在地下从掘进大巷入口处使用了高分辨率电阻率法以探测采空区的位置，从而方便15号煤层的挖掘的推进。2大地电阻率的特征 15号煤层是储备矿中主要的煤层。煤层的厚度主要在5.15m6.63m之间，平均厚度为5.89m，贯穿了整个储存区。煤层中主要为高热值的无烟煤，含有少量的中低组分的灰分以及极低的含硫量。采掘完毕后，如果采空区没有被水淹没，它的表面电阻率将会有明显地增加。无论整个采空区是否塌陷，都会呈现出高电阻率材料的特性。正是基于此种物理条件，我们选择使用高分辨率电阻率法对采空区进行探测。3地下高分辨率电阻率法 如上所述，好的煤层质量是决定高分辨率电阻率法能否使用的关键。需要使用何种设备来进行电阻率的勘探是值得更长远的研究的。事实上，采空区是一个人造的、孤立的地质体，并不是一个统一的层状矿床。因此需要利用一些可以叠加采空区的电子信息，定位采空区坐标，并且能够区分其与周围的岩石的特殊设备来探测这种地质体的类型。地下高分辨率电阻率法需要使用三个特殊的电极。单极偶极装置发射的电波更加的密集，提高了观测和控制的水平、增加了叠加的次数、放大信息量，从而提高了采空区探测的分辨率，使得采空区可以区别于周围的岩石群。图1为调查站的阵列图。图1 地下高分辨率电阻率法调查阵列图地下高分辨率电阻率法所采用的参数分别如下：1)供电站中间的距离为A，A=20m；2)调查站之间的距离为C，C=2m；3)极间距为MN，MN=10m；4)测线的半径为：线为140m、线60m；5)无限远处极杆坐标离测线12002000m远。地下调查数据通过防爆型的微伏数字直流电阻率计收集。在地下探测中，每间隔20m设有一座供电站。对于每个供电站，都需要记录两端电压差的不同。每个供电站两端两极间的最大距离为140m（因为偏移的最大距离为140m）。这样就可以实现双层覆盖观测，并且使得勘探区域可以覆盖到140m。采取以下措施以保证采取自地下数据得可靠性：