电磁法在金属矿勘查中的研究进展

Research progress of electromagnetic methods in the exploration of metal deposits

电磁法勘探是以地壳中各种类型的岩石矿体导电性、导磁性等电磁学的性质为基本依据,通过对各类电场及电磁场在空间上的分布规律及时间特征进行观测和研究,找到各种有用的矿体、探明区域地质构造以及解决具体地质问题的一种地球物理勘查方法.地球物理电磁法多年来已在世界各处的铜矿、钼矿、铅锌矿、铝土矿、深部铀矿、海底热液多金属硫化物矿等金属矿产资源勘查中起到了重要作用.为了在未来将该地球物理方法更好地应用于金属矿的勘探开发工作,有必要对各种电磁法在应用时表现出的优缺点及未来发展走势作出详细分析.本文主要针对电磁法在金属矿产资源勘查中的应用与发展,对电磁法勘探的原理、仪器、各种分支方法、数据处理技术、反演解释等方面做出比较全面的论述,同时介绍了电磁法在陆地、空中、海洋等不同环境中的找矿实例与应用效果.未来电磁法勘探仪器将朝着高精度高分辨率、集成化采集、实时处理能力强、便于携带的方向发展,数据处理方面将融合多种地球物理方法进行联合反演及开展多学科交叉研究,而且电磁法的应用领域不再局限于地面和井中,航空电磁法和海洋电磁法在未来金属矿勘查工作中有着广阔的应用前景.

The principle of electromagnetic exploration is based on the difference of conductivity and permeability in the crust of various types of rocks. Measurements to the exploration show the distribution of electric and magnetic fields in space and time domains. The method is applied for mineral exploration or mapping a geological structure or solving the specific geological problems. Electromagnetic method is applied as an important tool for mineral exploration, such as copper,molybdenum, lead-zinc, bauxite, deep uranium, volcanogenic massive sulfide deposits and other metal deposits. In order to improve the electromagnetic method, it is necessary to review the advantages and disadvantages for the electromagnetic method application of mineral exploration. In this paper, we are mainly focusing on the applications and progressing of electromagnetic method in the metal mineral exploration. We also review the development of electromagnetic method for instance, prospecting, equipment, bifurcation method, data processing, modeling, inversion and interpretation. The prospecting examples are reviewed in different environments including land, borehole, aviation and ocean. The electromagnetic prospecting instruments will develope in the direction of high precision, high resolution, integrated acquisition, real-time processing and portability in the future. The data processing will combine multiple geophysical methods for joint inversion and interdisciplinary research. Moreover, the application of electromagnetic data is no longer confined to the ground and the borehole. The airborne electromagnetic method and the marine electromagnetic method have a broad application prospect in the future of metal prospecting.