澳大利亚昆士兰州西北世纪锌铅银矿床的地球物理特征

GEOPHYSICS OF THE CENTURY ZINC?LEAD?SILVER DEPOSIT,NORTHWEST QUEENSLAND

世纪锌铅银矿床由ＣＲＡ 公司于１９９０ 年发现，并进行勘探。钻探圈定出锌（１０ ．３ ％ ） 、铅（１ ．５ ％ ） 、银（３５ ×１０ － ６） 的矿石量达１１ ６００ 万ｔ。矿床被发现以来，物探技术就应用于帮助确定矿化范围，不同岩性边界和构造的圈定，提供矿石储量的计算和采矿计划的资料以及该区下一步勘探工作帮助。使用的物探方法有重力、地面和航空磁法、地面和航空电磁、ＩＰ／ 电阻率法、钻孔物探测井及地震反射。最为有效的方法是ＩＰ／ 电阻率法。它可以帮助确定在深度至少为１５０ ｍ

The Century Zn Pb Ag deposit, located about 250 km north northwest of Mount Isa,Queensland,was discovered by CRA Exploration in 1990 following several years of regional area selection studies and initial reconnaissance field work.Post discovery drilling has outlined a resource containing 116 Mt of 10.3% zinc,1.5% lead,and 35×10 -6 silver.Geophysical techniques have been applied at Century since the discovery to help define the limits of mineralisation,map lithologic boundaries and structure,provide data for ore reserve estimates and mine planning,and to aid ongoing exploration in the area.Methods used have been gravity,ground and airborne magnetics,ground and airborne electromagnetics,IP/resistivity,downhole geophysical logging,and reflection seismic.The most useful technique to date has been IP/resistivity,which has assisted in mapping the extent of mineralisation beneath limestone and younger cover to depths of at least 150 m.