摘要
拉拉铜矿是我国西南地区最大的露天铜矿山,从发现至今经过数十年开采,面临资源枯竭,亟需开展深部找矿工作,以提高矿山资源储量。可控源音频大地电磁法(Controlled source audio-frequency magnetotelluric method,CSAMT)是一种在音频大地电磁法(Audio-frequency magnetotelluric,AMT)和大地电磁法(Magnetotelluric method,MT)基础上发而来的人工源频率域探测方法,近年来在深部找矿领域得到了广泛应用。为实现拉拉铜矿深部和外围找矿突破,结合矿区地质特征,采用CSAMT法进行深部勘查,共布设了13条测线,500个测点,在同一测点分别进行了高频和低频观测。通过对观测数据进行处理以及系列图件处理,结合矿区岩石电性特征与已知矿体分布情况的对比分析结果,优选出-5#、15#线进行典型剖面异常推断解译,并对推断解译剖面进行了钻探验证,在R3、R12异常附近均不同程度地见到铜矿体,品位为0.42%~0.74%、厚度为1.25~19.16 m,赋存标高为1 440~1 570 m。研究表明:钻孔见矿情况与异常解译推断成果吻合度较高,矿化区或蚀变带主要集中于视电阻率低阻条带上部或下部,低阻区中心或高阻区存在矿化蚀变的可能性较小,矿区内主要的含矿层位为天生坝组(Pt_1t)与落凼组(Pt_1n),当该2类地层中出现中高阻或中低阻接触带时,附近存在矿化蚀变带的可能性较大。
Lala copper deposit is largest open-pit copper mine in the southwest of chiua,it has been developed for decades,the phenomenon of resource depletion of the mine is becoming more and more serious. It is necessary to conduct the deep prospecting work of the mine,so as to increase resource reserves of the mine and extent the mine service life. Controlled source audio-frequency magnetotelluric method（ CSAMT） is belongs to the artificial source frequency-domain detection method,which is well developed based on audio-frequency magnetotelluric（ AMT） and Magnetotelluric method（ MT）. In recent years,CSAMT method is widely adopted in deep prospecting area. In order to realize the goal of the prospecting breakthrough of the deep area and adjacent area of the mine,CSAMT method is applied to conduct the deep prospecting exploration work,13 exploration lines and 500 exploration points are set. High frequency and low frequency measurement work is done respectively at the same exploration point. The measurement data is processed and some corresponding maps are drawn,based on the comparative analysis of the electrical characteristics of the rock mass in mining area and distribution features of the orebodies,-5-# and 15-# exploration lines are selected as the typical profiles to interpret the anomalies,besides that,the anomaly interpretation profiles are verified by drilling engineering,the copper ore-bodies are found in the depth of R3 and R12 anomalies that are delineated based on the above study results,grade of the ore-bodies is from 0. 42% to 0. 74%,thickness of them is from 1. 25 to 19. 16 m,and the distribution elevation of them is from 1 440 to 1 570 m. The study results indicated that： distribution characteristics of the ore-bodies is basically consistent to the results of anomaly interpretations,mineralized areas or alteration zones are mainly distributed in the upper or lower of the low resistance belt of apparent resistivity,there is less possibility of the mineralization alteration in the center of low resistance zone or high resistance zone,Tianshengba Formation（ Pt1t） and Luodang Formation（ Pt1n） are the main ore-bearing strata in the mining area,if the medium-low or medium-high resistance contact belts occurs in the strata,it is highly likely that the mineralized alteration belts exist in the adjacent areas of the contact belts.
作者
王毅
刘君
Wang Yi, Liu Jun(403 Geological Team, Sichuan Bureau of Geology ＆ Mineral Resource)
出处
《现代矿业》
CAS
2018年第4期19-25,30,共8页
Modern Mining
关键词
铜矿
CSAMT法
深部找矿
异常解译
矿化蚀变带
找矿突破
Copper deposit
CSAMT method
Deep prospecting
Anomaly interprelation
Mineralizedalteration belt
Prospecting breakthrough
作者简介
王毅（1974-），男，高级工程师，614200四川省峨眉山市兴隆街1号。
