Economic By-Products in copper Porphyries: Silver in the Ascutita Cu-Porphyry, Romania
Economic By-Products in copper Porphyries: Silver in the Ascutita Cu-Porphyry, Romania
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铜斑岩的经济副产品：罗马尼亚 Ascutita 铜斑岩中的银
DOI：
10.1016/j.oregeorev.2022.105135
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发表时间：
2022
影响因子：
3.3
通讯作者：
Eskdale A
中科院分区：
文献类型：
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作者：
Eskdale A
Ascutita斑岩铜钼远景区位于罗马尼亚西南部的Poiana Rusca山脉。目前的评估估计资源量为1.1亿吨，铜当量为0.15%。在这种品位相对较低的矿床中，银（2-3 ppm）等副产品对于确定整个矿体的经济可行性非常重要。铜和银在井下有明显的相关性。在没有其他含银矿物的情况下，或银与其他硫化物的相关性（例如，Pb指示含银方铅矿），这表明硫化铜是银的主要寄主。21个不同钻孔样品的岩石学特征表明，铜硫化物以黄铜矿为主，在空间上与两个阶段的黄铁矿相关。LA-ICP-MS分析确定黄铜矿和3期黄铁矿（较年轻）共同主导银。黄铜矿的银主要以固溶体形式存在，而黄铁矿的银则以各种复杂的亚硫酸盐微包裹体形式存在，在扫描电镜上无法检测到，但在时间分辨的LA-ICP-MS光谱上很明显。这些微包裹体锁住了Cu和Ag，总体中位数Ag含量为0.79 ppm。黄铁矿还含有平均浓度为52 ppm的铋和46 ppm的硒：这两种元素在冶炼厂都是典型的惩罚元素。黄铜矿的银浓度高于黄铁矿（中位数= 30.3 ppm，电位为181 ppm），可能是固溶体。晶格结合的银通过银+对铜+的单价简单取代而进入黄铜矿。银在Ascutita含铜主相的赋存，提高了联合回收的可能性，说明了微量元素分析在矿体地学评价中的价值。
The Ascutita porphyry Cu-Mo prospect is located in the SW Poiana Rusca Mountains, Romania. Current assessment estimates a resource of 110 Mt @ 0.15 % Cu-equivalent. In relatively low-grade deposits such as this, by-products such as Ag (2–3 ppm) are important in determining the economic feasibility of the overall orebody. Assayed Cu and Ag have a clear downhole correlation. In the absence of other silver-bearing minerals, or correlations of Ag with other sulphides (e.g., Pb indicating Ag-bearing galena) this suggests Cu-sulphides are instead the dominant hosts of Ag. Petrography of 21 samples from various drillholes show chalcopyrite is the dominant Cu-sulphide present, spatially associated to two stages of pyrite. LA-ICP-MS analysis determined that both chalcopyrite and Stage 3 pyrite (younger) co-host the Ag. Chalcopyrite hosts Ag mostly in solid solution, whilst pyrite hosts Ag within a variety of complex, sulphosalt micro-inclusions undetectable on an SEM, but apparent on time-resolved LA-ICP-MS spectra. These micro-inclusions lock in Cu and Ag, with a bulk median Ag content of 0.79 ppm. The pyrite also contains mean concentrations of 52 ppm Bi and 46 ppm Se: both typically penalty-incurring elements at smelters. The chalcopyrite has a greater Ag concentration than the pyrite (median = 30.3 ppm with potential for 181 ppm), presumably in solid solution. The lattice-bound Ag partitioned into the chalcopyrite through monovalent, simple substitution of Ag+for Cu+. Occurrence of Ag in the main Cu-bearing phase at Ascutita raises the possibility of combined recovery, and this study demonstrates the value of trace element analysis in geometallurgical assessments of orebodies.