综合物探在矿山深部资源勘查中的应用

Application of Comprehensive Geophysical Exploration in Deep Mines Resource Exploration

矿产资源是社会和经济发展必不可少的物质基础,目前国内多数老矿山面临已探明储量枯竭的严峻形势,现有的勘查知识和技术难以解决矿山找矿勘查所遇到的特殊难题。针对矿山找矿的特殊性,本文结合安徽省霍邱某矿区的地质及物探资料,在采矿区选取典型剖面进行重磁、微动及可控源音频大地电磁法(Controllable Source Audio Magnetotelluric Method,CSAMT)。以微动和音频大地电磁数据分析推测浅部矿体采空及塌陷区;在深部将微动勘探与重力数据结合,取长补短,通过剪切模量将微动视横波速度与地下介质密度直接联系起来,经已知矿体位置剪切模量的分布规律并结合重磁反演在300 m以深推测了两条近平行层状分布的矿体,矿体长200~250 m,最厚处约50 m;在标高100~200 m的类似S形褶皱拐点处可能为成矿有利位置;同时推测已知主矿体在底板以深还有延伸。通过本次工作,证实了在当前老矿区内,将新技术微动勘探与传统物探方法相结合,各取其长,能提高矿山深边部及外围隐伏矿床(体)定位预测的有效性,挖掘新的找矿潜力。

Mineral resources are an essential material foundation for social and economic development.Currently,most old mines in China are facing a severe situation of reserves depletion,tengh problems are hardly tackled using current technologies.In response to the particularity of mining exploration,based on geological and geophysical data from a certain mining area in Huoqiu,Anhui province,this paper selects typical profiles in the mining area for gravity,magnetism,micro motion and controlled source audio magnetotelluric method(CSAMT).Using micro motion and audio magnetotelluric data analysis to speculate on the goaf and collapse areas of shallow ore bodies,taking advantage of integrating micro motion exploration with gravity data in depth to compensate for weaknesses,and directly linking micro motion apparent shear wave velocity with underground medium density through shear modulus,based on the known distribution pattern of shear modulus at the location of the ore body and combined with gravity and magnetic inversion,this paper inferred two nearly parallel layered ore bodies with a length of 200~250 m and a thickness of about 50 m at depths of 300 m.The inflection point of a similar S-shaped fold at an elevation of 100~200 m is a favorable location for mineralization.At the same time,the main ore body is speculated to be extending beyond the bottom plate.The work has confirmed that new micro motion exploration technology combinedwith traditional geophysical methods in the current mining area can improve the effectiveness of locating and predicting hidden deposits(bodies)in the deep and peripheral areas of the mine,and tap into new prospecting potential.