中非成矿带刚果(金)如瓦西(Ruashi)铜-钴矿床经历了表生成矿作用,但其研究薄弱.在野外地质调查、室内矿物学观察和矿山生产勘探的基础上,对如瓦西铜-钴矿床的表生分带组构与次生富集规律进行研究.结果表明,该矿床原生矿体由黄铜矿、斑铜矿、硫铜钴矿等含铜硫化物矿物组成,矿石品位铜在1%～2%、钴在0.1%～0.3%范围内.矿床在近地表发生表生氧化作用后,上部形成了氧化带,可进一步划分为3个亚带:(1)完全氧化亚带;(2)淋滤亚带;(3)次生氧化物富集亚带.上部完全氧化亚带发育富钴氧化物堆积体"矿帽"(钴品位在1%～3%,部分可达12%),淋滤亚带几乎不含铜、钴金属矿物,次生富集氧化物亚带由孔雀石、硅孔雀石、蓝铜矿、胆矾、水胆矾等氧化物矿物和碳酸盐矿物组成,矿石品位铜在5%～10%、钴在0.8%～1.0%范围内,相对原生矿石富集了3～5倍.下部为次生硫化物富集带,出现蓝铜矿、辉铜矿等次生硫化物矿物,矿石品位铜在3%～5%、钴在0.3%～0.8%范围内,相对原生硫化矿富集了1～3倍.综合分析认为,如瓦西铜-钴矿床表生成矿作用受岩石地层、地质构造和地下水等因素的控制,次生富集作用明显提高了矿石品位和矿床开发价值,形成了氧化物富铜-钴矿、硫化物富铜-钴矿和碳酸盐岩接触带附近的氧化物富铜矿及黑色富钴矿等类型的高-特高品位矿体.经勘探验证,在矿区深边部新揭露高品位矿石资源量256万吨,平均品位铜为3.68%、钴为0.44%,可采储量143万吨,平均品位铜为3.53%、钴为0.32%.该研究可为矿区及区域同类型矿山硫化矿演化成氧化矿的表生富集过程及深边部找矿预测提供科学依据.
The Ruashi copper-cobalt deposit in the Central African Metallogenic Belt has undergone supergene oxidation and secondary enrichment,but the related research is weak.This work analyzed the composition of supergene zoning and its metallogenesis based on geological surveys,mineralogical observations and production resource exploration of this deposit.The primary orebodies contain sulfide minerals of chalcopyrite,bornite,chalcogenite,and the ore grade ranges in 1%～2%for copper and 0.1%～0.3%for cobalt.The upper oxidation belt can be further divided into three sub zones,i.e.,the complete oxidation subzone,the leaching subzone and the secondary oxide enrichment subzone.The complete oxidation subzone develops the"gossan"with cobalt-rich oxide accumulation(cobalt grade is 1%～3%,locally reaching up to 12%).The leaching subzone contains almost no copper and cobalt metal minerals.The secondary enriched oxide subzone includes oxide minerals of malachite,silicomalachite,azurite,chalcopyrite,and water chalcopyrite,as well as carbonate minerals.The ore grade is 5%～10%for copper and 0.8%～1.0%for cobalt,which is enriched by 3～5 times than the primary ore.The lower part is the secondary sulfide enrichment including chalcopyrite and chalcocite.The ore grade is within the range of 3%～5%for copper and 0.3%～0.8%cobalt,which is 1～3 times enriched than the primary sulfide ore.The study reveals that the Ruashi deposit has experienced multi-period and multi-stage metallogenic evolution,and the supergene oxidation zoning is controlled by factors such as rock stratum,geological structures,and groundwater.The secondary enrichment has significantly improved the ore grade and development value,which formed high to ultra-high grade ore bodies such as the Cu-Co-enriched oxide ore,Cu-Co-enriched sulfide ore,Cu-enriched oxide ore near the contact zone of carbonate rock and black Co-enriched ore.Exploration indicates that the newly discovered high-grade ore resources in the deep edge of the deposit are 2.56 million tons,with an average grade of 3.68%copper and 0.44%cobalt.The recoverable reserves are 1.43 million tons,with an average grade of 3.53%copper and 0.32%cobalt.This study can provide scientific basis for the epigenetic enrichment of sulfide deposits evolving into oxide deposits in the same type of mines and region,as well as for deep edge exploration prediction.
陶玻;王涛;李昶;贾宗明;白发青;薛明;田毓龙;邱正杰
金川集团股份有限公司,甘肃金昌 737100||梅特瑞斯如瓦西矿业公司,刚果(金)卢本巴西 20043金川集团股份有限公司,甘肃金昌 737100中国科学院地质与地球物理研究所,北京 100029
地质学
表生氧化;次生富集;找矿预测;高品位矿石;如瓦西铜-钴矿床;刚果(金)
supergene oxidation;secondary enrichment;prospecting prediction;high-grade ore;Ruashi Cu-Co deposit;D.R.Congo
《地质与勘探》 2024 (003)
631-642 / 12
金川集团股份有限公司如瓦西铜钴矿科技项目(编号:JKCCnull2019003)资助.
10.12134/j.dzykt.2024.03.018
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