Geophysical-Geological Interpretation and Deep-Seated Gold Deposit Prospecting in Sanshandong-Jiaojia Area, Eastern Shandong Province, China

Integrated gravitational, electrical-magnetic surveys and data processing carried out in the Sanshandao-Jiaojia area, Eastern Shandong Province, northeast China, aim to illuminate the geological characteristics of this shallow-covered area and delineate deep-seated gold prospecting targets. In this region, altogether 12 faults exert critical control on distribution of three types of Early Precambrian metamorphic rock series, i.e. those in the metamorphic rock area, in the granitic rock area underlying the metamorphic rock, and in the remnant metamorphic rock area in granites, respectively. Additionally, the faults have major effects on distribution of four Mesozoic Linglong rock bodies of granite, i.e. the Cangshang, Liangguo, Zhuqiao-Miaojia and Jincheng granites. The Sanshandao and Jiaojia Faults are two well-known regional ore-controlling faults; they have opposite dip direction, and intersect at a depth of 4500 m. Fracture alteration zones have striking geophysical differences relative to the surrounding county rocks. The two faults extend down along dip direction in a gentle wave form, and appear at some steps with different dips. These steps comprise favorable gold prospecting areas, consistent with a step metallogenic model. Six deep-seated gold-prospecting targets are delineated, i.e. Jincheng-Qianchenjia, Xiaoxizhuang-Zhaoxian, Xiyou-Wujiazhuangzi, Xiangyangling-Xinlicun, Panjiawuzi and Miaojia-Pinglidian.

Geophysical Prospecting of Karst Water in Yunnan Province,China

由于岩溶发育的不均匀性，决定了岩溶水的埋藏分布也具有不均匀的特征，含水层富水性的空间差异极大。岩溶水的不均匀性给岩溶水勘查和开发工作带来了很大的困难，以至于裸露型岩溶石山区的供水勘探孔成井率仍然很低。要有效地发挥岩溶水资源的优势，合理有效地开发岩溶水资源，解决岩溶地区严重干旱缺水问题，关键是解决找水难的问题。要解决岩溶地区普遍存在的找水难题，

Application Strategy of Integrated Geophysical Prospecting in the Treatment of a Tunnel Disease

China is a country with complex terrain and complex geological conditions.With the development of economy and society,the demand for transportation is also increasing.There are many railways on the mountainous areas.Geological diseases severely affect the construction quality and safe operation of the tunnel,causing huge economic losses.This paper introduces the principles and application strategies of these technologies.

Application of Environmental Geophysical Prospecting in Environmental Quality Investigation of Reclaimed Land

Traditional geophysical prospecting methods( electromagnetic induction method,high-density resistivity method and ground penetrating radar method) were applied to the environmental quality detection of reclaimed land in the "198" area of Shanghai. According to the results of drilling sampling and laboratory analysis,the accuracy,suitability and consistency of theses geophysical prospecting methods were evaluated.

Time-lapse geophysical technology-based study on overburden strata changes induced by modern coal mining

To study the impact of modern coal mining on overlying strata and its water bearing conditions,integrated time-lapse geophysical prospecting integrating 3D seismic,electrical and ground penetrating radar method were used.Through observing and analyzing the geophysical data variations of all stages of pre-mining,mining and post-mining as well as post-mining deposition stable period,impacts of coal mining on stratigraphic structure and its water bearing were studied and modern coal mining induced stratigraphic change pattern was summarized.The research result shows that the stratigraphic structure and the water bearing of surface layer during modern coal mining have self-healing pattern with mining time;the self-healing capability of near-surface strata is relatively strong while the roof weak;water bearing selfhealing of near-surface strata is relatively high while the roof strata adjacent to mined coal beds low.Due to integrated time-lapse geophysical prospecting technology has extra time dimension which makes up the deficiency of static analysis of conventional geophysical methods,it can better highlight the dynamic changes of modern coal mining induced overburden strata and its water bearing conditions.

An integrated ore prospecting model for the Nyasirori gold deposit in Tanzania

The Nyasirori gold deposit,located in the middle-western end of the Musoma-Mara Archean greenstone belt in Tanzania,is a tectonic altered rock type gold deposit controlled by shear tectonic zone.This work conducted high-precision ground magnetic measurements to delineate fault structures and favorable prospecting targets,utilized induced polarization(IP)intermediate gradient to roughly determine the distribution and extension of the tectonic altered zone and gold ore(mineralized)bodies,and further carried out IP sounding and magnetotelluric sounding to locate the tectonic altered zone and gold ore(mineralized)bodies.The anomalous gradient belt of the combination of positive and negative micromagnetic measurements reflects the detail of shallow surface tectonic alteration zone and gold mineralization body.Micromagnetic profile anomalies indicate the spatial location and occurrence of concealed tectonic alteration zone and gold(mineralized)ore bodies.Soil geochemical measurements indicate that the ore-forming element Au correlates well with As and Sb,and As and Sb anomalies have a good indication to gold orebodies.Based on the multi-source geological-geophysical-geochemical information of the Nyasirori gold deposit,this work established an integrated prospecting model and proposed a set of geophysical and geochemical methods for optimizing prospecting targets.

A Critical Analysis of Gold Prospecting Methods

Exploration and prospecting for mineral resources deposits are perceived to not be an easy process due to big deposits being discovered in early times. Numerous gold prospecting methods have been used in gold prospecting. The aim of this research is to critically analyze both traditional and modern gold prospecting methods that are being used in gold exploration. The research objective is to critically evaluate the numerous studies that focus on gold prospecting methods in an effort to provide an effective analysis of gold prospecting methods. In doing so, the study has used a qualitative method to review the existing literature. The study reviews academic journals and articles, books, and periodicals which were published between 2010 and 2019. This study has achieved to critically analyze both traditional and modern gold prospecting methods. The study finds out that the traditional gold prospecting methods include gold panning and dry washing. Additionally, the current gold prospecting methods include biological prospecting, geochemical prospecting and geophysical prospecting methods.

Discussion on the application prospect of the transient electromagnetic method based on the dual launcher and mine advanced detection

The dual transmitter implements the equivalent anti-magnetic flux transient electromagnetic method, which can effectively reduce the scope of the transient electromagnetic detection blind area. However, this method is rarely reported in the detection of pipelines in urban geophysical exploration and the application of coal mines. Based on this, this paper realizes the equivalent anti-magnetic flux transient electromagnetic method based on the dual launcher. The suppression effect of this method on the blind area is analyzed by physical simulation. And the detection experiment of underground pipelines is carried out outdoors. The results show that the dual launcher can significantly reduce the turn-off time, thereby effectively reducing the impact of the blind area on the detection results, and the pipeline detection results verify the device’s effectiveness. Finally, based on the ground experimental results, the application prospect of mine advanced detection is discussed. Compared with other detection fields, the formation of blind areas is mainly caused by the equipment. If the dual launcher can be used to reduce the blind area, the accuracy of advanced detection can be improved more effectively. The above research results are of great significance for improving the detection accuracy of the underground transient electromagnetic method.

Low-altitude geophysical magnetic prospecting based on multirotor UAV as a promising replacement for traditional ground survey

The prospects for expanding the mineral resource base in many countries are linked with the exploration of stranded sites localized at unexplored areas with complex natural and landscape conditions that make any ground survey,including magnetic prospecting,difficult and expensive.The current level of geology requires high-precision and large-scale data at the first stages of geological exploration.Since 2012,technologies of aeromagnetic surveying with unmanned aircraft vehicles(UAV)enter the market,but most of them are based on big fixed-wing UAV and do not allow to substantially increase the level of survey granularity compared with traditional aerial methods.To increase the scale of survey,it is necessary to reduce the altitude and speed of flight,for which the authors develop the methodical and technical solutions described in this article.To obtain data at altitudes of 5 m above the terrain even in a rugged relief,we created heavy multirotor UAVs that are stable in flight and may be used in a wide range of environmental conditions(even a moderate snowfall),and develop a special software to generate flight missions on the basis of digital elevation models.A UAV has special design to reduce magnetic interference of the flight platform;the magnetic sensor is hung below the aircraft.This technology was conducted in a considerable amount of magnetic surveys in the mountainous regions of East Siberia between 2014 and 2016.The results of the comparison between airborne and ground surveys are presented,which show that the sensitivity of the developed system in conjunction with low-altitude measurements can cover any geologically significant anomalies of the magnetic field.An unmanned survey is cheaper and more productive;the multirotor-based technologies may largely replace traditional ground magnetic exploration in scales of 1:10,000−1:1000.

河南省嵩县九仗沟-东湾金矿区深部地球物理特征与找矿预测

深部金属矿探测是目前资源勘查的重要课题和方向,地球物理方法探测深度大、分辨率高,是深部金属矿探测最有效的手段之一。河南省嵩县九仗沟—东湾矿区处于熊耳山—外方山矿集区内的蛮峪—店房金矿带之北段,目前九仗沟—东湾矿区已发现的金矿床主要为500 m以浅深度,深部(500~2000 m)找矿勘查工作基本为空白。为了查明九仗沟—东湾矿区深、边部成矿潜力,实现接替资源找矿突破,在九仗沟—东湾矿区主矿段南北两端延伸方向上,布设EH-4双源大地电磁测深和大功率激电测深剖面。以九仗沟—东湾金矿床为背景,在分析地质背景、岩石物理性质基础上,综合区域重磁资料、物探剖面反演结果,分析各物探方法异常特征,厘清了研究区内与金矿有关的F1构造破碎蚀变带深部空间分布特征等信息,揭示了研究区内深部F1构造带附近的中低电阻、高极化区为找矿有利部位,根据此特征在500~2000 m深度范围内确定了4个深部预测找矿靶区,为下一步找矿勘查提供了相关依据。研究方法和成果为区域上开展同类型金矿床的深部找矿工作提供了思路和方向,具有重要的指导和实践意义。

A Ground Penetrating Radar and Electrical Resistivity Tomography Prospection for Detecting Sterile Bodies in the Phosphatic Bearing of Sidi Chennane(Morocco)

In Sidi Chennane deposits (Morocco), the phosphatic series is composed of regular interbedded phosphatic and marly limestone layers. Exploitation of the phosphate in these deposits collides frequently with problems bound to the existence, in this series, of sterile bodies qualified as derangements. They cause two kinds of problems: 1) as they are hard, compact and masked by a Quaternary cover, they disturb the exploitation in some yards and give bad reserve calculation;2) even the use of wells and mechanical boreholes did not evidence their delimitation. Our study shows that these bodies can be detected and delimited using ground penetrating radar and electrical resistivity tomography methods. It is based on the acquisition and the interpretation of series tests using these methods carried out above visible sterile bodies in a trench of exploitation in order to have geologically valid information. The article concerns to the analysis of the results and of the proceeding for a possible large geophysics survey.

坦桑尼亚恩泽加地区覆盖区选区评价及综合找矿方法研究

恩泽加(Nzega)绿岩带为坦桑尼亚环维多利亚湖八大绿岩带之一,为坦桑尼亚重要的产金区域之一。由于其地表覆盖程度较高,地质调查和勘查工作程度较低,虽然针对隐伏型金矿床尚具备一定的找矿潜力,但同时也面临选区评价和找矿困难的问题。研究表明:在选区评价中,针对太古界尼安萨群条带状铁建造的区域航磁异常解译和研究区地球化学金异常分析是最主要的;而在采用地物化综合找矿方法开展勘查工作中,磁法和激电法结合对于寻找覆盖区下的含铁建造内部或接触带附近或剪切带内的金矿床效果较好。该地区首次使用了取样钻施工采样,对覆盖层下发育的含金矿化蚀变带进行了地质工程揭露,取得了一定的找矿成果,先后发现了伊博罗格罗(Iborogo)、卢素(Lusu)和乔马(Choma)等多个金矿床(点)。

甘肃北山红柳园—辉铜山地区成矿地质条件、地球化学特征及找矿新发现

甘肃北山红柳园—辉铜山地区位于甘肃北山南带,是形成铜、镍、铁、铅锌、钼、金、银等矿床的有利地区,具有较好的找矿潜力。通过开展成矿地质条件分析,总结控矿关键因素,依据水系沉积物地球化学特征,确定Au、Ag、As、Sb、Hg、W、Sn、Ni、Cu为区内主要的成矿(伴生)元素。Ni、Cu异常与基性-超基性侵入岩的分布有关,Au异常受华力西中期似斑状花岗岩及加里东晚期石英闪长岩控制明显,与区域性断裂及其旁侧平行或“入”字斜交的次级断裂关系密切。异常查证新发现铭扬铜镍矿、杨帆金矿等多处矿点及矿化线索,结合区域地质、物探、化探特征,优选出4处具较大成矿潜力的找矿远景区,尤其是早古生代铭杨铜镍矿的发现,实现了北山地区近年来铜镍矿找矿新突破。研究成果可为下一步找矿勘查部署提供重要依据。

适应川西地区复杂油气地质条件的物探技术探讨

川西地区以负向构造为主,多期构造演化叠加,断裂发育、储层致密,气水关系复杂,物探采集、成像及储层预测技术适应性较差。概要介绍了分公司在川西地区油气勘探开发历程,总结了随着地质目标变化而形成的物探关键技术及其发展过程,分析了现有采集、处理、解释技术对地质目标的适用性及优缺点,剖析了侏罗系近源薄互层致密砂岩气藏、须家河近源致密气藏以及山前带超深层碳酸盐岩气藏等下一步重点勘探开发目标的研究难点,展望了高精度成像、低频资料储层预测、多尺度断裂系统刻画以及油气水识别等关键物探技术的发展和应用前景,对应用物探前沿技术支撑川西复杂油气区高效勘探开发具有一定的指导意义。

矿井探地雷达背景杂波抑制方法综述

随着中国煤炭安全高效智能开采需求的不断提升,矿井探地雷达(ground-penetrating radar, GPR)作为一种高精度物探方法,在煤矿井下探测中有广阔的应用前景。由于探地雷达目标回波信号受系统内部噪声、外部电磁干扰、巷道回波、地下介质不均匀等干扰影响,虚警率较高。尤其对于小尺寸目标,其回波信号为弱信号,容易淹没在强烈的背景杂波中,成为目前制约探地雷达探测性能的主要因素之一,进一步实现井下煤层、构造探测、提高探测精度的关键在于对背景杂波的抑制。从对消法、滤波法、分解法和网络法出发,综述这些杂波抑制方法的基本原理、优缺点及其在探地雷达干扰抑制领域的研究进展,并探讨各种方法的适用范围和发展潜力。杂波抑制技术的不断创新将进一步提高探地雷达的信噪比与灵敏度,使其在煤矿井下探测中发挥更大的应用价值。

物探测井在贵州省瓮安县草塘镇地热勘查井中的应用研究

通过贵州省瓮安县草塘镇地热井的地球物理测井案例,综合分析了自然伽马、电阻率、自然电位、补偿时差、井径等物理参数在不同岩石上的测井响应特征。对井中的实测曲线进行了综合地质解释,解译了地层层位、岩性、井斜、井温、典型标志层和含水层等,为地热井下实管、下筛管等提供了科学依据,提高了地热井勘探的成井率,从而确定了地球物理测井是提高开发地热井成井率的一项重要措。

基于高斯混合聚类的综合物探方法及其在岩溶勘探中的应用

综合物探是一种有效的岩溶勘探技术,但其预测结果中存在人为影响大、溶洞边界模糊等缺点.首先,基于机器学习技术,采用高斯混合模型,分别对高密度电法和面波法勘探数据做分类处理;然后,提出Category-boundary算法,进一步细分上述分类得到的边界,提高高斯混合模型分类精度;最后,根据专家经验与地勘资料制定分类融合规则,在勘察数据驱动和工程地质知识引导的有机结合下,形成一套综合物探的高精度分类融合新方法.将新方法应用于浙南某岩溶勘探工程,获得了边界清晰的溶洞探测结果,与实际钻孔信息对比高度吻合,验证了新方法的有效性.

综合地球物理方法在中深层地热资源勘查中的应用综述

地热能作为一种清洁低碳、可循环利用的稳定能源,其开发利用对于推动温室气体减排,实现碳中和、碳达峰目标具有重要意义。目前,中国资源开发利用主要集中在浅层地温能方面,中深层地热能勘探受储层埋深大、勘查手段单一等影响勘查难度较大,为提高地热勘查效率,需引入成本低、环境破坏性小、施工效率高、探测深度大的地球物理技术。本文介绍了近年来中深层地热资源调查采用的重、磁、电、震等多种地球物理方法的基本原理与应用概况,并对不同地球物理方法的特点和适用条件进行了对比分析,为不同的地质背景条件与地热勘探阶段物探方法的选择提供借鉴经验。

机器学习在地球物理勘探中铀矿资源勘查的应用研究进展

机器学习有自动性、高准确性、可扩展性等优势,适用于大数据处理和自适应任务。在地球物理勘探中运用,可大幅提高勘探效率和准确性,促进技术进步,实现地球物理向智能化解译的发展。文章首先介绍了机器学习在地球物理领域的常用先进方法,如深度学习、深度神经网络、BP神经网络、支持向量机和随机森林的基本原理和分类特点。其次介绍了放射性勘探、地球物理测井、成矿预测和联合反演的基本原理,同时对前人在机器学习应用到这4方面地球物理领域的实际应用进行综合分析,结果表明,机器学习在这4个领域中的应用均取得了显著的效果。通过机器学习技术的应用,地球物理勘探能够取得更加全面、精准和高效的成果,同时也能推动这项技术的不断进步。