Ce travail présente les résultats dune étude menée sur la dépollution des tailings de Kipushi (RD Congo) par la valorisation des métaux contenus. Ce sont les rejets anciens dun concentrateur. Ils contiennent de la pyrite et des sulfures résiduels de cuivre et de zinc. Du fait du stockage à lair libre pendant plus de 40 ans, ces sulfures sont partiellement oxydés. Ces tailings présentent une certaine instabilité physique et chimique qui est à la base de la dégradation des milieux environnants les plus proches (rivières naturelles, sols sous-jacents, nappes souterraines, etc.) suite à la migration et à la dispersion dETM (éléments traces métalliques) tels que larsenic, le cadmium, le cobalt, le cuivre, le plomb, le zinc, Linstabilité physique se manifeste par des phénomènes dérosion par les eaux de ruissellement pendant la saison des pluies et par des phénomènes dérosion éolienne pendant la saison sèche. Leur stockage en surface saccompagne dune lente oxydation des sulfures avec production deaux acides qui dans leur neutralisation par la dolomie présente dans les rejets et celle des formations géologiques sur lesquelles ils reposent, contribuent à laccroissement des réseaux karstiques, au durcissement des eaux des nappes et parfois provoquent des phénomènes daffaissements, voire même deffondrements de terrains. Pour réduire les impacts environnementaux majeurs de ces tailings, nous avons effectué ce travail en recherchant un traitement qui combinerait dune part la dépollution par la réduction des ETM et du soufre sulfure et dautre part la valorisation du cuivre et du zinc contenus. Les deux voies qui ont été testées commencent par une flottation globale de tous les sulfures (désulfuration environnementale). Les résultats de nos expérimentations montrent quon peut obtenir un nouveau rejet de flottation dans lequel une majeure partie des ETM facilement mobilisables dans lenvironnement est éliminée ainsi que presque tout le soufre (95 %), ce qui écarte donc tout risque de DMA. Nous avons démontré que pour atteindre ces résultats, il suffit de ne broyer que la fraction la moins libérée de dimension supérieure à 75 μm et dactiver par un prétraitement à pH 6 les sulfures dont la collection par le xanthate est sinon inhibée par laltération superficielle avec formation doxydes ou par les complexes cyanométalliques formés lors de la flottation avec dépression de la pyrite par les ions cyanures ayant produit les tailings étudiés. Nous avons tenté denrichir le concentré global de la désulfuration environnementale par une flottation différentielle avec dépression de la pyrite à pH 11. Cet enrichissement est difficile à réaliser à cause de la finesse des grains et des caractéristiques minéralogiques du concentré global qui contient beaucoup de grains mixtes. Les essais ont alors porté sur la lixiviation chimique acide oxydante (avec Fe3+) et la lixiviation bactérienne du concentré global après son enrichissement en cuivre et en zinc dans un circuit de flottation avec deux finissages. Une étude approfondie des paramètres qui influencent le mécanisme des biolixiviations a été effectuée et les conditions de leur mise en pratique industrielle ont été déterminées. La lixiviation chimique doit être réalisée à des températures élevées (98°C) pour fragiliser la couche de passivation de soufre élémentaire qui se forme à la surface des grains et qui tend à freiner la diffusion des réactifs et des produits de la réaction. Par contre, la biolixiviation donne de bons résultats à température modérée. Elle est techniquement applicable aux tailings de Kipushi. Nous proposons de réaliser la biolixiviation en deux étapes successives, la première avec des bactéries thermophiles modérées (55°C) à une densité de pulpe de 15 % (poids/volume) et la deuxième avec des bactéries mésophiles (33°C) sur des pulpes à 4 % de solides. Dans ces conditions, on réussit à produire deux solutions de lixiviation (PLS : pregnant leach solution), lune à 3 g/l de cuivre et 7 g/l de zinc et lautre à 0,2 g/l de cuivre et 7 g/l de zinc, quon purifie et concentre facilement dans un circuit dextraction par solvant. Lextraction par solvant du cuivre est réalisée avec le LIX984N directement sans modifier le pH des PLS (1,7-1,9) et le zinc est extrait par le D2EHPA après précipitation dions Fe3+ du raffinat cuivre à des pH entre 3 et 3,5. On obtient ainsi des solutions aqueuses de cuivre et de zinc convenant aux installations délectrolyse industrielle. Nous avons proposé un schéma de traitement des tailings de Kipushi qui pourrait fonctionner pendant 20 ans avec les 36 684 600 tonnes sèches de rejets stockés à la digue 1 et 2. Le traitement produirait un nouveau rejet plus ou moins dépollué qui représente 66 % en poids des tailings traités, 80 950 tonnes de cuivre et 631 750 tonnes de zinc. The work present results from research study devoted to de-pollution of the stocked tailings in Kipushi (DR Congo) via valorization of the metals contained in the tailings. Pyrite and copper and zinc sulfides present the principal mineral composition of the laid down tailings from the concentrator. Due to the fact that the sulphides have been stocked during more than 40 years, they are partly oxidized. These tailings present a constant risk from physical instability and spillage, which reflects in the deterioration of the surrounding environment (rivers, soil, underground water table, etc). Moreover the migration and dispersion of TEM (trace metal elements) such as arsenic, cadmium, cobalt, copper, lead, zinc, is leading to erosion and mine run-off phenomena during wet season and generate air-borne particles during dry season. The stocking of the tailings is accompanied by slow oxidation of the sulfides with concomitant production of acidic waters which are neutralized by the dolomite present, which finally reflects in hardening of the underground waters and even provoke soil subsidence and ground collapses. In order to reduce the major environmental impacts from the tailings, we have performed a study for their post-treatment which encompasses the cleanup from one side and the reduction of TEMs and sulphur on the other side. Apart from this, the aim was to economically extract the remaining non-ferrous metals, notably Zn and Cu. The approach which has been chosen to accomplish this task has been to re-float by bulk flotation the majority of the sulphides and thus by elimination of the nearly total sulphur (95 %) to eliminate the risk of AMD generation and metals immobilization. We have shown that this is possible to be achieved via grinding the 75 μm oversize fraction in order to facilitate minerals liberation, following by subsequent activation at pH 6 before flotation. Without this pretreatment step, the flotation by use of xanthates is impossible, due to the surface coatings of the grains, which are either of oxide nature or are cyano-metallic complexes formed from the use of potassium cyanide as pyrite depressor in the flotation circuit practiced at the times when the concentrator was operational. The further attempts to produce monometallic flotation concentrates via selective flotation with depression of the pyrite at pH 11 have been unsuccessful due to reasons of complex mineralogy. Therefore chemical (Fe3+) and bacterial leaching of the bulk concentrate enriched in Cu and Zn via two cleaning flotation circuits have been envisaged. The technological parameters for the both leaching options have been studied and the mechanisms of the bioleaching taking place have been proposed in view industrial scale up of the process. It has been found that the chemical leaching should be conducted at very high temperatures (98°C) in order to breakdown the passivation coatings (sulphur). In contrast, the bioleaching has shown good results at moderate temperatures. It has been found that bioleaching is technically feasible to the tailings of Kipushi. We have suggested a bioleaching in two successive stages: the first one with moderate thermophilic microorganisms (55 °C) at pulp density 15 % (weight / volume) and the second one with mesophilic microorganisms (33 °C) at pulp density of 4 % (w/v). Under these conditions two principal PLSs (pregnant leach solution) can be obtained - a one with 3 g/l Cu and 7 g/ l Zn and other one in 0.2 g/l Cu and 7 g/l Zn. The both PLSs could be further processed via solvent extraction. The solvent extraction of Cu is accomplished with LIX984N without modifying the pH of the PLS (1.7 - 1.9), while Zn is extracted using a D2EHPA at pH between 3 and 3,5, after elimination of the iron from the copper raffinate. The aqueous solutions thus obtained are suitable for Cu and Zn electrowinning. Finally, a flow sheet for re-treatment of the Kipushi tailings which could operate during 20 years has been proposed. It could treat about 37 mln tones of dry tailings stocked in the tailing ponds 1 and 2. Preliminary calculations estimate that such treatment would produce new tailings with low environmental risk which will represent about 66 % in weight of the original treated tailings and will yield about 80 950 tons of Cu and 631 750 tons of Zn.

Les unités ophiolitiques du Queyras (zone Alpes occidentales) représentent des petits massifs de roche vertes dispersées dans les Schistes lustrés piémontais à l'Ouest du Mont Viso. Leur étude permet de reconstruire la structure du substratum d'une partie du segment ligure de la Téthys. Bien que de nombreuses observations de terrain conduisent à envisager une coupure majeure entre la mise en place des ultramafites et gabbros associés et l'épanchement des basaltes, l' analyse pétrographique et géochimique permet de conclure à un assemblage cohérent et comparable avec d'autres massifs ophiolitiques de l' Apennin et de la Corse. Les résultats obtenus soulignent le caractère tholéïtique de la lignée magmatique à l'origine des matériaux basiques, intermédiaires et acides des différentes unités. La typologie des zircons conforte cette hypothèse au niveau des roches acides. La répartition des éléments inertes, Y, Ti, Zr, Nb, montre les liens cogénétiques entre les matériaux basiques et les différenciats acides. La nature du fractionnement ainsi que l'estimation du degré de fusion partielle suggèrent une mise en place dans un environnement géotectonique à caractère transitionnel avec océanisation à proximité de marges continentales passives, ainsi qu'un magmatisme analogues à ceux à l'origine des ophiolites de la Méditerranée occidentale (magmatisme de type I). Les éléments de granitoïdes d'une brèche sédimentaire localisée à l' interface ultramafites-laves, se caractérisent par un cachet calcoalcalin et permettent d'envisager la proximité d'une croûte continentale dont le démantèlement a vraisemblablement été contemporain des stades précoces de l'ouverture de l'océan ligure. Les circulations hydrothermales liées à ce contexte océanique sont responsables des processus de spilitisation et des minéralisations localisées à l'interface substratum océanique / sédiments: le gîte Fe/Cu de Viafiorcia (Val Germanasca, Italie) en est un exemple.

L'étude de la cristallogénèse de deux composés destinés a des applications optiques non linéaires dans l'infrarouge, AgGaS2 et AgGaSe2, a été entreprise. Après avoir presenté et vérifié les propriétés structurales et thermodynamiques de ces matériaux, les paramètres influant sur la qualité des cristaux ont été étudiés et la nature et la répartition des défauts intrinsèques déterminées. Des mesures de tenue au flux laser a 1.06 m sur des monocristaux polis ont été effectuées. Deux expériences de doublage a 10.6m ont été réalisées. Une étude numérique de la convection dans la phase fluide durant la cristallogénèse a été entreprise afin d'interpreter les défauts structuraux et/ou de composition induits par les instabilites hydrodynamiques.

Ionometallurgy is a new trend to utilise ionic liquids as alternative green solvents for oxidic and sulfidic copper minerals. It has broad potential for traditional pyrometallurgy and hydrometallurgy. Ionometallurgy utilises ionic liquids (ILs), highly potent complexing ligands (chloride), to process oxide and copper sulfide minerals. This work focused on using the deep eutectic solvents (DES) of ionic liquids, which and provide alternative options for processing various metals, alloys, and concentrates. For this job, various analytical methods were used to determine the copper concentrate and its residue after leaching (MLA-SEM and XRPD), quantify the elements in the solution (IC and ICP-OES/MS) and explain the oxidation behaviour (CV and UV-Vis spectroscopy). Combining the analytical and electrochemical methods to the leaching experiment provided the control to improve the results and understand its oxidation behaviour. Chosen DES, Oxaline (ChCl + oxalic acid, 1:1), and Ethaline (ChCl + ethylene glycol, 1:2) were tested and enhanced on the actual copper concentrates with and without oxidative additives (FeCl3 and I2). Those oxidative additives are selected for leaching experiments by their redox potential in Ethaline. However, there are many acceptable values; the most exciting result related to Ethaline plus iodine was the potential leaching system for chalcopyrite and copper-gold concentrates leaching. Because ion chromatography (IC) and UV-Vis’s analysis confirm iodine oxidizes the Cu+ species quickly in Ethaline. Whilst identical results and oxidation behaviour appeared in chalcocite (Cu2S), chalcopyrite (CuFeS2) and copper-gold concentrates leaching. During the iodine reduction to iodide in the system, IC proved that chalcopyrite releases the Fe3+, oxidizing the chalcopyrite particles. Also, iodine oxidized the natural gold in copper-gold concentrate successfully, and gold concentration quantified ICP-MS and MLA-SEM proved there is no visible gold in the leaching residue. Based on the optimal Ethaline + I2 leaching condition, the copper concentrate was carried out with the bottle roller leaching to represent the tank leaching. Thus, DES shows that it has a high potential to be continued to scale up the experiment. Also, water was given to the Ethaline leaching system, and water had a good influence on the leaching due to reducing the viscosity and saving the Ethaline amount. Hence Ethaline plus water is used for the copper ore leaching in the column, and it can be seen that Ethaline + I2 with water (up to 20%) has a high potential to process the low-grade copper sulfide ores.:Acknowledgements Abstract Abbreviations TABLE OF CONTENTS CHAPTER ONE – INTRODUCTION OF COPPER PROCESSING TECHNOLOGIES 1.1. Overview 1.2. Copper 1.3. Gold 1.4. Hydrometallurgy and pyrometallurgy of copper and gold 1.5. Current copper and gold concentrate processing methods 1.6. An alternative copper concentrate processing method Summary of chapter 1 CHAPTER TWO – FUNDAMENTALS FOR PROCESS DEVELOPING 2.1. Introduction 2.2. Effect of temperature and stirring in leaching 2.3. Analytical methods and experimental 2.4. Experimental for leaching 2.5. Discussion of experimental errors CHAPTER THREE: ANALYTICAL EXPERIMENTS FOR LEACHING 3.1. Introduction 3.2. Analysis of copper concentrate 3.3. Cyclic voltammetry 3.4. UV-Vis spectroscopy analysis of target metals 3.5. Metals solubility in DES 3.6. Summary and conclusions CHAPTER FOUR: FUNDAMENTAL LEACHING EXPERIMENT AND INITIAL INVESTIGATION 4.1. Introduction 4.2. Initial study and fundamental leaching experiments 4.3. Study of mineral oxidation 4.4. Deep eutectic solvents leaching 4.5. Chapter summary and conclusion CHAPTER FIVE: LEACHING OF MODEL SYSTEMS IN ETHALINE WITH OXIDATIVE ADDITIVES 5.1. Introduction 5.2. Iodine effect on Cu2S and CuS leaching in Ethaline 5.3. Ferric chloride effect on CuS and Cu2S leaching 5.4. Leaching of natural gold in Ethaline with the presence of iodine 5.5. Cyclic voltammetry investigation of Cu+/2+ sulfides in DES 5.6. Chapter summary and conclusion CHAPTER SIX: LEACHING OF COPPER-GOLD CONCENTRATES IN DES AND WITH OXIDATIVE ADDITIVES 6.1. Introduction 6.2. Effect of ferric chloride (FeCl3) 6.3. Effect of iodine (I2) 6.4. Electrochemical and spectroscopic analysis of copper-gold concentrate leachates 6.6. Chapter summary and conclusion CHAPTER SEVEN: OVERALL CONCLUSION AND FUTURE WORK 7.1. Overall conclusions 7.2. Recommendations for future research CHAPTER EIGHT: APPENDIX 8.1. Chemicals and materials 8.2. Appendix References

Abstract Polymetallic (Pb-Zn-Cu-Ag-Au-Sb-As-Bi-Cd-Te-Se-Ge…) quartz veins occur in an area from Eidsvoll in southeastern Norway to west of LakeVänern in southwestern Sweden. They most likely formed during the waning stage of the c. 1 Ga Sveconorwegian orogeny. In Värmskog parish, Värmland county, several mineralized quartz veins of different types are known. Of these, three of the larger vein deposits, Vegerbol, Karlsbol and Södra Gärdsjön, have been investigated. Despite a history of mining activities (mostly for silver) and exploration from the mid-1800s up until the present day, details about their ore mineralogy have remained essentially unknown. In order to classify and characterize them better, the present study was undertaken. The main ore minerals in the veins are galena, sphalerite, chalcopyrite, tetrahedrite sensu lato and pyrite. Additionally, this investigation showed the occurrence of an array of silver-bearing phases such as argentian tetrahedrite to freibergite, native silver, polybasite, pyrargyrite, jalpaite, aguilarite, cervelleite, hessite and matildite. These are the main and accessory silver carriers in the studied deposits. Gold (argentiferous) was also found, as well as the nickel-cobalt sulphide siegenite.    The silver contents of the tetrahedrites may vary within one deposit, ranging from tetrahedrite sensu stricto to freibergite. A weak positive correlation occurs between silver and iron in the tetrahedrites. Cadmium was found both in the tetrahedrites and in the sphalerites. Many sphalerites, however, are very pure ZnS. The complex accessory ore mineralogy, including native gold as well as tellurium and selenium-bearing phases (Vegerbol), makes these vein deposits comparable to mineralized veins to the west and southwest of the Värmskog area.    Combining mineralogical and textural observations with previous studies, the vein mineralizations most likely formed during a change in tectonic regime, in recurrently active brittle structures, at temperatures ranging from c. 350 down to below 100°C. The occurrence of pyrite and hematite and the lack of pyrrhotite and magnetite points to an oxidizing ore-forming environment with relatively high sulphur activity.    Finally, in order to assess the possibility of connecting two of the mined vein systems, VLF (Very Low Frequency) electromagnetic measurements were performed across the strike of a possible continuation between the Vegerbol and Karlsbol deposits. The VLF survey showed a significant anomaly where such a continuation was to be expected, thus indicating an overall strike length of at least 1 km for that vein system. / Sammanfattning Polymetalliska (Pb-Zn-Cu-Ag-Au-Sb-As-Bi-Cd-Te-Se-Ge…) kvartsgångar förekom­mer inom ett område från Eidsvoll, Norge i norr, till sydväst om Vänern i Sverige. De tros ha bildats under den svekonorvegiska orogenesens (ca 1 Ga) slutskede. I Värmskogs socken, Värmland, förekommer mineraliserade kvartsgångar av flera olika typer. Bland dessa har tre undersökts med avseende på malmmineralogi. Dessa kallas för Vegerbol, Karlsbol och Södra Gärdsjön, och de har brutits i huvudsak på silver. Trots att brytning och prospekteringsarbeten pågått från 1800-talet fram till i dag har det saknats detaljerade mineralogiska beskrivningar över fyndigheterna. Denna studie har genomförts för att bättre kunna karakterisera och klassificera dessa mineralis­eringar. Huvudmalmmineral vid dessa förekomster är blyglans, zinkblände, koppar­kis, pyrit och för Södra Gärdsjön även tetraedrit. Denna undersökning har påvisat förekomsten av silverförande faser som silverhaltig tetraedrit till freibergit, gediget silver, polybasit, jalpait, aguilarit, cervelleit, hessit och matildit, vilka utgör både huvudsakliga och accessoriska silverbärare i de undersökta förekomsterna. Guld (silverhaltigt) har också hittats, samt ett Ni-Co-förande mineral, siegenit.    Silverinnehållet i tetraedriterna varierar inom en och samma förekomst, några analyser har givit freibergitsammansättningar. En svag positiv korrelation finns mellan silver och järnhalt i tetraedrit. Kadmium förekommer både i tetraedrit och i zinkblände. Många zinkbländen består dock av rent ZnS. Förekomsten av relativt komplexa accessoriska mineral inklusive guld och Se-Te-faser (Vegerbol) visar att dessa gångar är jämförbara med liknande förekomster väster och sydväst om Värmskogs­området.    Genom att sammanföra data från denna undersökning med sådana från tidigare studier gjorda på gångarna kan man anta att de bildats vid vid en förändring av den tektoniska miljön, i upprepat aktiva spröda strukturer och vid temperaturer mellan ungefär 350 till under 100 °C. Förekomsten av pyrit och hematit samt avsaknad av magnetkis och magnetit tyder på att malmbildningen skett under oxiderade förhållan­den och relativt hög svavelaktivitet.      Elektromagnetiska mätningar i VLF-bandet (Very Low Frequency) utfördes tvärs över den förmodade strykningsriktningen för en möjlig fortsättning av gången mellan Karlsbol och Vegerbol. Mätningarna gav en tydlig anomali där en sådan fortsättning kan förväntas vilket skulle kunna betyda att det finns en sammanhängande mineralisering med ca 1 kilometers längd.

In the present work, novel dewatering aids and a novel centrifuge configuration were developed and applied for the purpose of dewatering fine particles. Three different types dewatering reagents were tested in different filtration and centrifugation units. These chemicals included low-HLB surfactants, naturally occurring lipids, and modified lipids. Most of these reagents are insoluble in water; therefore, they were used in solutions of appropriate solvents, such as light hydrocarbon oils and short-chain alcohols. The role of these reagents was to increase the hydrophobicity of the coal and selected mineral particles (chalcopyrite, sphalerite, galena, talc, clay, phosphate, PCC and silica) for the dewatering. In the presence of these reagents, the water contact angles on the coal samples were increased up to 90o. According to the Laplace equation, an increase in contact angle with the surfactant addition should decrease the capillary pressure in a filter cake, which should in turn increase the rate of dewatering and help reduce the cake moisture. The use of the novel dewatering aids causes a decrease in the surface tension of water and an increase in the porosity of the cake, both of which also contribute to improved dewatering. A series of batch-scale dewatering tests were conducted on a variety of the coal and mineral samples using the novel dewatering aids. The results obtained with a Buchner funnel and air pressure filters showed that cake moistures could be reduced substantially, the extent of which depends on the particle size, cake thickness, drying time, reagent dosage, conditioning time, reagent type, sample aging, water chemistry, etc. It was determined that use of the novel dewatering aids could reduce the cake formation time by a significant degree due to the increased kinetics of dewatering. At the same time, the use of the dewatering aids reduced the cake moistures by allowing the water trapped in smaller capillaries of the filter cake. It was found that final cake moistures could be reduced by 50% of what can be normally achieved without using the reagents. However, the moisture reduction becomes difficult with increasing cake thickness. This problem can be minimized by applying a mechanical vibration to the cake, spraying a short-chain alcohol on the cake and by adding a small amount of an appropriate coagulant, such as alum and CaCl2 to the coal and mineral slurries. The novel dewatering aids were also tested using several different continuous filters, including a drum filter, disc filter and horizontal belt filter (HBF). The results obtained with these continuous filtration devices were consistent with those obtained from the batch filters. Depending on the coal and mineral samples and the type of the reagent, 40 to 60% reductions in moisture were readily achieved. When using vacuum disc filters, the cake thickness increased substantially in the presence of the novel dewatering aids, which could be attributed to the increased kinetics of dewatering. A dual vacuum system was developed in the present work in order to be able to control the cake thickness, which was necessary to achieve lower cake moistures. It was based on using a lower vacuum pressure during the cake formation time, while a full vacuum pressure was used during the drying cycle time. Thus, use of the dual vacuum system allowed the disc filter to be used in conjunction with the novel dewatering aids. Its performance was similar to that of HBF, which is designed to control cake thickness and cake formation time independently. The effectiveness of using the novel dewatering aids were also tested in a full-continuous pilot plant, in which coal samples were cleaned by a flotation column before the flotation product was subjected to the disc filter. The tests were conducted with and without using novel dewatering aids. These results were consistent with those obtained from the laboratory and batch-scale tests. The novel centrifuge developed in the present work was a unit, which combined a gravity force and air pressure. The new centrifuge was based on increasing the pressure drop across the filter cake formed on the surface of the medium (centrifuge wall). This provision made it possible to take advantage of Darcy s law and improve the removal of capillary water, which should help lower the cake moisture. A series of tests were conducted on several fine coal and mineral particles and obtained more than 50% moisture reduction even at very fine particle size (2 mm x 0). Based on the test results obtained in the present work, two proof-of-concept (POC) plants have been designed. The first was for the recovery of cyclone overflows that are currently being discarded in Virginia, and the other was for the recovery of fines from a pond in southern West Virginia. The former was designed based on the results of the plant tests conducted in the present work. Cost vs. benefit analyses were conducted on the two POC plants. The results showed very favorable internal rates of return when using the novel dewatering aids. Surface chemistry studies were conducted on the coal samples based on the results obtained in the present investigation. These consisted mainly of the surface characterization of the coal samples (surface mineral composition, surface area, zeta potential, x-ray photoelectron microscopy (XPS)), acid-base interactions of the solids and liquids, dewatering kinetic tests, contact angle measurements of the coal samples and surface force measurements using AFM. In addition, carbon coating on a silica plate using palsed laser deposition (PLD) and Langmuir-Blodgett (LB) film deposition tests were conducted on the sample to better understand the surfactant adsorption and dewatering processes. The test results showed that the moisture reductions on the fine particles agree well with the surface chemistry results. / Ph. D.

A quartz diorite intrusion of probable early Tertiary age that crops out over at least 6 square miles in the Palo Verde Ranch area in Pinal County, Arizona was mapped as a distinct intrusion. The quartz diorite intrudes an area comprising Pinal Schist, Oracle granite, andesitic flows, granoaplite, and dike rocks including both pegmatite and diabase. Two major physical features, the Owl Head Buttes and Chief Buttes volcanic areas, both remnants of an extensive early Tertiary series of flows of intermediate composition that covered the area, now remain as lava-capped buttes above the pediment. Weak but persistent fracture-controlled copper mineralization is found in the quartz diorite and the Pinal Schist at or near their mutual contacts in the form of chrysocolla, malachite, black copper oxides, chalcocite, chalcopyrite, and bornite, in decreasing order. Pyrite is rare. Alteration related to northeast and northwest-trending fractures increases in intensity from the common propylitic to argillic to the northeast toward the San Juan claims area. A barely discernible increase in copper sulfides mirrors the alteration zoning, although geochemical sampling showed background copper in the quartz diorite to be more uniform away from fractures.