Host of the Sustut Copper deposit, 230 miles (370 km) northwest of Prince George, is a 600 m thick sequence of volcaniclastic rocks of the upper member of the Upper Triassic Moosevale Formation. This unit strikes northwesterly and dips about 20 degrees to the south. Regional stratigraphic nomenclature has been rather confused but the latest subdivision by Monger and Church (1977) was used for this report. The Moosevale Formation is mostly conglomerate and volcanic breccia with local discontinuous and thin layers of tuffaceous rocks. Fragments in the unit are mainly basic to intermediate volcanic rock. Six relatively common types of fragments are recognizable as being derived from coeval volcanism. Logging of 10,000 ft of diamond drill core representing four cross-sections through the main ore zones was done in a rigorous manner on a coding form designed for input into a computer. Computer output led to a rabid visual and quantitative evaluation of the data, particularly as regards to physical characteristics and internal stratigraphy of the host unit. No stratigraphic subdivision within the upper member of the Moosevale Formation was accomplished. Thin section study of metamorphic mineral assemblages indicated the metamorphic grade of the host rocks is prehnite-pumpellyite facies. This grade is higher than that in other rocks of the same lithologic units at equivalent stratigraphic levels elsewhere. Copper-rich zones with economic potential appear to be restricted to the upper 60 m of the 600 m thick, coarse-grained volcaniclastic host, though there are minor occurrences throughout. The copper minerals, mainly chalcocite, bornite, chalcopyrite and native copper, are epigenetic and occur with quartz, epidote, prehnite, and carbonate in veinlets and in tabular zones parallel to bedding. Pyritized rock surrounds some copper-bearing tabular zones. Veins are negligible in total volume of mineralized rock and formed mainly by open space filling; both open space filling and metasomatism were operative to variable degrees in tabular mineralized zones. A crude vertical zoning is apparent in some tabular zones, where the idealized sequence from margin to core is: pyrite-chalcopyrite-bornite-chalcocite-native copper. Most tabular zones show neither the complete sequence nor a perfectly symmetric distribution of zones about a native copper core, and in some cases there is no semblance of a zonal distribution of ore minerals. Specific ranges of textural parameters (such as sorting, grain size, etc.) of the host rock, have been found to have been particularly amenable to the occurrence of copper minerals. These quantified textural parameters have been.compared statistical1y with copper mineralization and illustrate the correlation of copper minerals with volcaniclastic rocks that have sedimentary features indicating a high porosity and probably a high permeability prior to mineralization. These, porous units within the vol caniclastic pile are represented by the tabular copper zones. Copper minerals and non-metallic metamorphic minerals were precipitated from the same solutions, both in veins and relatively porous tabular zones. A limited geothermometry, based on sulphide phase relations and an interpreted origin to intergrowth textures, is consistent with temperatures of deposition of 250 - 300*C indicated by gangue mineral assemblages. The tabular copper zones and local sets of veinlets appear to have formed interconnected channelways permeable to ore fluids that presumably were derived from below. Age of mineralization is uncertain but vertical mafic dykes that cut the Moosevale Formation stratigraphically above the main mineralized zones are cut by veins and thus are premineralization. The upward flow of the hot solutions within a structural zone defined now by swarms of Cu-bearing veinlets produced a confined geothermal high that resulted in a local node of prehnite-pumpel1yite facies. metamorphism and con-comittent development of copper minerals and pyrite. Tabular zones with interstitial ore fluid represent loci of f1uid-wal1 rock reaction and ore-mineral zoning may be attributed in-part to diffusion outward from these loci. Sequential development of ore minerals as indicated by paragenetic studies and the observed zonal distribution requires an ore fluid initially more oxidizing than the basaltic country rock. Continued reaction to produce first native copper followed" successively by chalcocite, bornite, chalcopyrite and finally pyrite, resulted in the ore solution nearing equilibrium with the host. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 83-86).

Porphyry copper deposits represent one of the largest copper reserves on Earth. They typically contain large, low-grade reserves of primary ore and higher-grade, supergene enrichment blankets of sulfide and oxide ores. Understanding the mineralogy of porphyry copper ores and ores related to porphyry copper systems is exceedingly important for several reasons, foremost of which are the information provided by ore mineral parageneses, assemblages, and mineral chemistry on evolution of these magmatic-hydrothermal systems, and information on mineral processing characteristics of the ores. The focus of this work is to better understand the mineralogy of supergene copper sulfides in porphyry copper systems and hypogene base metal lodes related to porphyry copper systems, and use this mineralogical knowledge to improve our understanding of the processes responsible for ore formation. The objectives of this study are accomplished by two means: focusing on the crystallography and crystal chemistry of minerals, and then applying this mineralogical knowledge to a supergene sulfide enrichment blanket and hypogene massive sulfides from base metal lodes in southeastern Arizona. The discovery of a new mineral, natropalermoite, NaSr2Al4(PO4)4(OH)4, provided the opportunity to use single-crystal X-ray diffraction to solve a crystal structure, and electron-probe microanalysis (EPMA) to study the crystal chemistry of natropalermoite and how the accommodation of Na in the structure changes lengthens the unit cell along [010] and shortens it along [100] and [001] compared to its lithium analogue, palermoite. Solution of the crystal structure of the mineral nickelskutterudite, (Ni,Co,Fe)As3, allowed for the investigation of anion deficiency in minerals of the skutterudite group, a problem whose solution has eluded researchers for nearly 100 years. Two skutterudite (CoAs3) and two nickelskutterudite samples were analyzed using single-crystal X-ray diffraction, EPMA, and procrystal electron density. The results showed fully-occupied anion sites and a cation surplus, which was accommodated in the icosahedral site, proving that minerals of the skutterudite group are not anion deficient. This mineralogical knowledge was applied to the supergene enrichment blanket in the Western Copper section of the Morenci mine, Greenlee County, and hypogene massive sulfide deposits associated with a porphyry copper deposit at Bisbee, Cochise County, Arizona. This is one of very few studies of supergene sulfide blankets ever completed. One drill hole through the supergene blanket at Western Copper was examined using ore microscopy and EPMA. Results showed dominant (Cu+Fe):S ratios of 1.80 ± 0.05, 1.92 ± 0.03, and 1.10 ± 0.10, with higher (Cu+Fe):S dominant high in the blanket and low ratios dominant near the base of the blanket. These values were interpreted to be controlled by activity of Cu2+, Fe2+, and Fe3+ in solution. Massive sulfide deposits at Bisbee were investigated using ore microscopy and EPMA in order to correct the previous conflicting reports of the mineralogy and paragenesis of this famous district and interpret constraints on conditions of ore-forming fluids. Results show four types of ore: chalcopyrite-rich with hematite and/or pyrite, bornite-rich, chalcocite-rich, and a Zn-Pb association. Chalcopyrite-rich ores formed first, followed by bornite-rich and chalcocite-rich ores. All ores were formed at relatively shallow depths from oxidized, moderately sulfur-rich fluids; early fluids were higher temperature and later fluids were lower temperature and considerably more sulfidized. Zinc-lead ores formed early and were continuously dissolved and reprecipitated distal to Cu-mineralization. These patterns are similar to many other base-metal lode districts worldwide, however Bisbee contains more Zn-Pb ore than other districts with hematite-containing ores and less than those without hematite.

The geology, petrology and geochemistry of Catface porphyry Cu (Mo-Au) deposit, located on the west coast of Vancouver Island are examined in detail. Detailed core logging and sampling was carried out to characterize the geometry and identity of different intrusive phases and alteration styles prevalent during the emplacement and formation of the deposit, as well as their geochemical affinity. Early- and late-stage potassic alteration is identified, as well as main-stage sodic-calcic and calcic-sodic alteration. Four distinct Paleogene intrusive phases vary from quartz diorite to granodiorite in composition. The rocks are broadly calc-alkaline, weakly peraluminous to moderately metaluminous, and have typical arc geochemical affinity. The timing of emplacement and mineralization is constrained by U-Pb and Re-Os geochronology at 40.4-41.4 Ma and 40.9 ±0.2 Ma, respectively. All four Paleogene Catface intrusive phases were emplaced close in time with a direct temporal correlation to mineralization. The chalcopyrite- and pyrite-bearing miarolitic cavities in the Halo Porphyry intrusive, combined with U-Pb and Re-Os dates suggest this intrusive phase is the most likely source of mineralizing fluids. The intrusions were emplaced at depths of less four kilometers in the crust, as evidenced by the presence of miarolitic cavities and confirmed through amphibole-plagioclase thermobarometry, which record conditions of 615–700 °C and <200 MPa. The lack of primary anhydrite and hematite, and the presence of pyrrhotite in the ore system indicate a reduced magmatic-hydrothermal event. The SO3 contents in apatites are <450 ppm, indicative of a degassed and/or sulphate-free (reduced) magma. The assemblage K-feldspar-quartz-biotite-ilmenite yields oxygen fugacities (fO2) which are 0.5 to 3.0 log units below the quartz-fayalite-magnetite (QFM) buffer at an assumed pressure of 300 MPa; orders of magnitude more reduced than typical porphyry deposits. Parental magmas to the Catface deposit were either derived from intrinsically-reduced mantle, or more typical oxidized arc magma that was subsequently reduced during ascent and emplacement. Further isotopic work is required to determine which process contributed to the reduction of these magmas in an arc setting. Nevertheless, recognition of reduced porphyry-related magmatism on west-central Vancouver Island is of similar age to that of North Fork (~36.8-38.9 Ma) deposit in Washington suggesting a consanguinity of reduced magmatism with the Paleogene Cascade arc. / Graduate

The Kinsevere mine is a copper deposit located in the Democratic Republic of Congo (DRC), within the Central African Copperbelt. This area is situated in the Katangan basin within the SE portion of the Lufilian Arc, which is a large, arcuate structure that extends from SE Angola, across the DRC, and into NW Zambia. The purpose of this study is to characterise the brittle deformation observed around the Kinsevere copper deposit to lead to an understanding of the deformation history of the area. This is accomplished by analysing fault-slip and fold data to help understand the relationship between regional palaeostress, faulting and folding present in the mine vicinity. This study also attempts to characterise fracture-controlled copper mineralisation within the interpreted geodynamic context of the area. The broader objective of this study is to relate the structural observations from Kinsevere to the deformation history of the Lufilian Arc. This study uses the right dihedral method to analyse four categories of brittle structures. The structural types analysed include slickensided faults, mineralised joints, and unmineralised joints and shear fractures. The data suggests that the palaeostress associated with the formation of brittle structures in the Kinsevere area occurred during three deformation events. The first event is characterised by a compressional stress regime which occurred during the early stage of the Kolwezian phase (D1). The second event is characterised by a strike-slip stress regime that formed as the result of clockwise rotation of the earlier (D1) compressional regime. Two fault-slip vectors were observed on the strike-slip fault planes, indicating that a reactivation occurred during the Monwezian phase (D2). The final structural event was characterised by the development of an extensional stress regime. This was associated with North-South oriented extension and is related to the East African Rift System (D3). These interpreted events correlate well with the geodynamic context related to the Lufilian orogeny. Another line of evidence that supports this structural interpretation is the presence of evaporitic minerals observed in the stratigraphic units surrounding the brecciated zones such as the RAT and the CMN. The structural association of these evaporitic minerals may be related to pre-existing, salt-bearing units, which were dissolved during an early compressive (D1) phase of the Lufilian orogeny. However, the contact between the Grey RAT and the Red RAT (distal from the breccia zones) does not show any evidence of faulting, and in the Kinsevere area the Grey RAT is always observed above the Red RAT. This suggests that the Grey RAT may be the uppermost stratigraphic unit of the RAT subgroup, which contradicts some previously published interpretations. Thus, the current structural architecture was probably formed from a combination of two separate mechanisms, including compression-related salt extrusion and the development of thrust faults and folding resulting from the shortening of the Katangan basin. Based on an analysis of the fracture-controlled mineralisation in the study area, it is shown here that most of the stress tensors indicate that these fractures were induced within the compressional stress regime generated by the Lufilian orogeny. This conclusion supports studies which suggest a multiphase origin for the mineralizing fluids active in the Katangan basin. Thus, the age of the copper mineralisation associated with fractures is interpreted to correlate with the timing of the folding event that occurred during the Lufilian orogeny between 540-550Ma. / Dissertation (MSc)--University of Pretoria, 2012. / Geology / unrestricted

La nécessité de maximiser la récupération d'une ou plusieurs espèces utiles d'un gisement du cuivre, l´optimisation des consommations d'additifs dans le processus de traitement métallurgique, savoir où laisser les matériaux qui dans le futur pourraient être valorisés par une série de nouvelles opérations etc., conduit à adapter la planification minière aux caractéristiques géologiques et métallurgiques du gisement.Les unités géo-métallurgiques sont déterminées par une combinaison des principaux paramètres géologiques, type de roche, altération, minéralisation, etc. Chaque unité présente un comportement différent au processus de traitement métallurgiques avec des caractéristiques de récupération et de consommation d'acide bien spécifiques.D´une façon générale, on peut définir la planification de la mine comme un outil permettant de faire la liaison entre la géologie et la métallurgie, non seulement selon des paramètres économiques et de teneurs, mais aussi selon des paramètres géologiques et métallurgiques.Pour pouvoir construire le modèle géo-métallurgique ou géo-minier métallurgique (G.M.M) ainsi que mettre en oeuvre la catégorisation des ressources, nous avons utilisé des outils géostatistiquesLe fait de disposer d´un modèle G.M.M est d'une grande aide pour la définition de la fosse finale et la planification à long terme, soit simplement comme une première approche de la réponse du gisement au processus de traitement métallurgique, mais surtout pour optimiser les coûts et définir différentes alternatives pour maximiser la récupération du métal.Cette étude a été appliquée au cas du gisement stratiforme de Cu et Ag de Mantos de la Luna situé dans le Nord du Chili. Il comporte en particulier une comparaison entre l'approche traditionnelle et l'approche qui intègre le concept du modèle G.M.M. qui porte principalement sur les teneurs de coupure. Le concept G.M.M. peut donc influencer les décisions stratégiques comme les décisions opérationnelles. / The present research work concerns the general field of mining project set-up and is aimed at developing a new approach in long term mine planning. The main objective of this work is to incorporate the geo-metallurgical concept to mine planning which is traditionally based only on economic criteria.The need to maximize the recovery of one or more useful elements of a copper deposit, the optimization of reagents consumption in the metallurgical process, to know where to leave the materials which may be valorise in the future by a series of new operations, etc.. lead to fit mine planning and metallurgical geological features of the deposit. The geo-metallurgical units are determined by a combination of the main geological parameters, rock type, weathering, mineralization, etc... Each unit has a different behaviour in metallurgical process with specific values of recovery and acid consumption.The set-up of the geo-metallurgical mining model (GMM) and the resources categorization were made using geostatistical tools.Having a GMM model is a great help for the definition of the ultimate pit and long-term planning, as well as in a first approach of the response of the deposit to metallurgical process, but also to optimize costs and establish alternatives to maximize metal recovery.This work is based on the practical case of the Mantos de la Luna stratabound Cu and Ag deposit located in northern Chile. It proposes a methodology for resources classification of this type of deposit and includes a comparison between the traditional approach and the approach that integrates the concept of the GMM model.