坦桑尼亚Maheiga金矿地球物理特征与找矿标志

Geophysical characteristics and prospecting indicators of the Maheigagold deposit in Tanzania

坦桑尼亚Maheiga金矿属于隐伏的条带状铁建造型金矿,与条带状含铁建造(BIF)密切相关;通过对区域上和矿区内的岩(矿)石磁性参数和磁力异常特征的分析研究,表明赋矿的条带状含铁建造和金矿石具强磁特性,两者会在地表引起变化幅度较大的异常响应,由此归纳提取出呈带状展布的ΔT强负磁异常为Maheiga金矿的地球物理找矿信息标志,确定磁力勘探是寻找隐伏的条带状铁建造型金矿的最佳首选方法,其勘查组合流程为:(1)利用航磁异常发现和圈定BIF聚集分布区;(2)利用地面高精度磁测寻找隐伏—半隐伏含铁建造体;(3)利用精测剖面正反演拟合计算,确定BIF的连接关系、形态及赋存部位.此模式,已成功应用于坦桑尼亚Maheiga金矿外围的物探勘查中,有效地指导了该地区此种类型的金矿勘查,目前矿区与外围已探明(332+333)金金属资源量34吨.

The Maheigagold mining belongs to concealed iron formation type gold deposit in Tanzania,It is closely related to banded iron formation（BIF）in the country;by the analysis on magnetic parameters and magnetic anomaly characteristics of the rock（ore）in the region and mining area,it suggests that gold ore and banded iron formation related to gold deposit are with strong magnetic properties,only banded iron formation and gold ore body can cause abnormal response of large variations in the surface,so the scale and intensity of magnetic anomaly on the ground magnetic survey should be caused by banded iron formation;thus,it can be concluded that ΔT strong negative magnetic anomaly in banded distribution for geophysical prospecting indicators of Maheigagold mine,to determine that magnetic exploration is the best preferred method for prospecting concealed the banded iron formation modelling gold deposits,its exploration combination process is：（1）using aeromagnetic anomalies to find and delineate the BIF gathered area;（2）to find concealed-half concealed iron formation body by using the ground high-precision magnetic survey;（3）making the use of precision profile in forwardinversion calculation, to determine the BIF connection relations,shape and occurrence position.Seting up this model,It has been applied to the Maheigagold deposits in peripheral area,effectively guide for this type gold ore exploration in the region in Tanzania, At present,the mining area and the periphery have proved gold metal resources of 34 tons（332＋333）.