Economic Geology and Geochemistry

Mineral resources are Nature's endowment to humanity; they are to be discovered, extracted and used for our economic benefit. However, economic minerals are very 'scarce' and non-renewable resources that require the training and expertise of geoscientists to find, explore and exploit. The insatiable demand for mineral raw materials to meet the needs of a growing world population, and rising standard of living has created the urgent need to train more economic geologists who understand the complex processes responsible for the occurrence, distribution and origin of mineral deposits, and know how to apply the acquired knowledge in the search for new mineral deposits. Economic geology is the scientific study of mineral resources and the application of such knowledge in mineral exploration and mining. This book is an introductory text on the geology of mineral deposits for undergraduate and postgraduate geology and mining students, particularly in Africa. This book "goes back to the basics" of a rapidly-growing applied geoscience, and systematically describes the essential aspects of the distribution, mode of occurrence, characteristics and origin of the major mineral deposit types, including metallic and industrial minerals and rocks, and gemstones, with examples from worldwide , but mainly from Africa-the world's most mineral-rich continent. For the benefit of Mining students, this work integrates mineral deposits geology into a continuum with mineral exploration and mining geology. The book is adequately illustrated with maps and pictures, and written in a simple and concise language that is easily understood, and adapted to the needs students from developing countries where textbooks are scarce, and if available are too expensive to be affordable. The book content is organized into two parts with eight chapters: Part One is focused on the Principles of Economic Geology with five chapters: Chapter 1: Introduction to Economic Geology; Chapter 2: Nature of Mineral Deposits; Chapter 3: Ore Forming Processes and Associated Deposits; Chapter 4: Economic Geology of Metals; and Chapter 5: Industrial Minerals and Rocks, Part Two of the book is dedicated to Applied Economic Geology with three chapters: Chapter 6: Mineral Exploration; Chapter 7: Elements of Mining Geology; and Chapter 8: Environmental Geology in Mining Operations. A Glossary of Common Terms in Economic and Mining Geology is included at the end of the book. The book is intended for Geology and Mining students at "upper" undergraduate and postgraduate levels at Universities and Polytechnics (HND). Also, practicing geoscientists and mining professionals who need to "brush up" their knowledge in economic geology, will find the book very useful. The format of the book is topical and well organized for teaching courses on Mineral Deposits and Mining Geology at undergraduate and postgraduate levels. It is an expanded version of lecture notes used over the years in teaching Economic and Mining Geology at Universities and Community Colleges, augmented by extensive field experience and literature research.

Mineral resources are Nature's endowment to humanity; they are to be discovered, extracted and used for our economic benefit. However, economic minerals are very 'scarce' and non-renewable resources that require the training and expertise of geoscientists to find, explore and exploit. The insatiable demand for mineral raw materials to meet the needs of a growing world population, and rising standard of living has created the urgent need to train more economic geologists who understand the complex processes responsible for the occurrence, distribution and origin of mineral deposits, and know how to apply the acquired knowledge in the search for new mineral deposits. Economic geology is the scientific study of mineral resources and the application of such knowledge in mineral exploration and mining. This book is an introductory text on the geology of mineral deposits for undergraduate and postgraduate geology and mining students, particularly in Africa. This book "goes back to the basics" of a rapidly-growing applied geoscience, and systematically describes the essential aspects of the distribution, mode of occurrence, characteristics and origin of the major mineral deposit types, including metallic and industrial minerals and rocks, and gemstones, with examples from worldwide , but mainly from Africa-the world's most mineral-rich continent. For the benefit of Mining students, this work integrates mineral deposits geology into a continuum with mineral exploration and mining geology. The book is adequately illustrated with maps and pictures, and written in a simple and concise language that is easily understood, and adapted to the needs students from developing countries where textbooks are scarce, and if available are too expensive to be affordable. The book content is organized into two parts with eight chapters: Part One is focused on the Principles of Economic Geology with five chapters: Chapter 1: Introduction to Economic Geology; Chapter 2: Nature of Mineral Deposits; Chapter 3: Ore Forming Processes and Associated Deposits; Chapter 4: Economic Geology of Metals; and Chapter 5: Industrial Minerals and Rocks, Part Two of the book is dedicated to Applied Economic Geology with three chapters: Chapter 6: Mineral Exploration; Chapter 7: Elements of Mining Geology; and Chapter 8: Environmental Geology in Mining Operations. A Glossary of Common Terms in Economic and Mining Geology is included at the end of the book. The book is intended for Geology and Mining students at "upper" undergraduate and postgraduate levels at Universities and Polytechnics (HND). Also, practicing geoscientists and mining professionals who need to "brush up" their knowledge in economic geology, will find the book very useful. The format of the book is topical and well organized for teaching courses on Mineral Deposits and Mining Geology at undergraduate and postgraduate levels. It is an expanded version of lecture notes used over the years in teaching Economic and Mining Geology at Universities and Community Colleges, augmented by extensive field experience and literature research.

A desktop study and geological analysis on current Wetar Project datasets were carried out to establish certain key criteria which related to the volcanic massive sulphide mineralization processes and the deposition of economic resources in the Wetar mineralization district. The primary objective is to identify deposit-scale exploration targets with potential to be developed into mineable copper and/or gold reserves within Batutua’s tenements at Wetar Island.

The first stage of the study is the identification of regional tectonic scale structures that may concentrate the flow of fluids (magma and metal-bearing fluids). The intersection of structural zones, characterized by inverted rifts, defines the prospective mineralization belts and determines camp-scale and deposit-scale targets.

Camp-scale and deposit-scale targeting involves analyses and interpretation of more detailed geological and structural datasets, together with geophysical and mineral occurrence data to define specific areas of exploration potential.

All targets are ranked on a technical basis utilizing ASC criteria and a simple numerical scoring scheme. Key criteria comprise favorable geological setting including specific host rocks, uplift and erosion rates, prospect scale faulting, post-mineral cover and mineral occurrences or alteration assemblages. 

Keyword: Area Selection Criteria (ASC), Wetar mineralization district, volcanic massive sulphide (VMS), camp-scale target, deposit-scale target

Mineral resources are Nature's endowment to humanity; they are to be discovered, extracted and used for our economic benefit. However, economic minerals are very 'scarce' and non-renewable resources that require the training and expertise of geoscientists to find, explore and exploit. The insatiable demand for mineral raw materials to meet the needs of a growing world population, and rising standard of living has created the urgent need to train more economic geologists who understand the complex processes responsible for the occurrence, distribution and origin of mineral deposits, and know how to apply the acquired knowledge in the search for new mineral deposits. Economic geology is the scientific study of mineral resources and the application of such knowledge in mineral exploration and mining. This book is an introductory text on the geology of mineral deposits for undergraduate and postgraduate geology and mining students, particularly in Africa. This book "goes back to the basics" of a rapidly-growing applied geoscience, and systematically describes the essential aspects of the distribution, mode of occurrence, characteristics and origin of the major mineral deposit types, including metallic and industrial minerals and rocks, and gemstones, with examples from worldwide , but mainly from Africa-the world's most mineral-rich continent. For the benefit of Mining students, this work integrates mineral deposits geology into a continuum with mineral exploration and mining geology. The book is adequately illustrated with maps and pictures, and written in a simple and concise language that is easily understood, and adapted to the needs students from developing countries where textbooks are scarce, and if available are too expensive to be affordable. The book content is organized into two parts with eight chapters: Part One is focused on the Principles of Economic Geology with five chapters: Chapter 1: Introduction to Economic Geology; Chapter 2: Nature of Mineral Deposits; Chapter 3: Ore Forming Processes and Associated Deposits; Chapter 4: Economic Geology of Metals; and Chapter 5: Industrial Minerals and Rocks, Part Two of the book is dedicated to Applied Economic Geology with three chapters: Chapter 6: Mineral Exploration; Chapter 7: Elements of Mining Geology; and Chapter 8: Environmental Geology in Mining Operations. A Glossary of Common Terms in Economic and Mining Geology is included at the end of the book. The book is intended for Geology and Mining students at "upper" undergraduate and postgraduate levels at Universities and Polytechnics (HND). Also, practicing geoscientists and mining professionals who need to "brush up" their knowledge in economic geology, will find the book very useful. The format of the book is topical and well organized for teaching courses on Mineral Deposits and Mining Geology at undergraduate and postgraduate levels. It is an expanded version of lecture notes used over the years in teaching Economic and Mining Geology at Universities and Community Colleges, augmented by extensive field experience and literature research.

The main aim of this paper is to review and compare the various geochemical assessments that have been carried out on the Nigerian phosphates with a view to encourage local and international investors to develop and exploit these deposits. Nigeria is located on latitude 100 North and longitude 80 East surrounded in the north by Niger and Chad and in the east by Cameroun and in the west by Benin Republic. The comparative geochemical assessments of the Nigerian phosphates show that they compare favourably with deposits from Togo, Morocco, Jordan, USA, Algeria, China, etc. With the current economic reforms and investment incentives in Nigeria, interested investors are highly welcome to take advantage of developing these deposits

The top 10 reasons in support of the Peak Gold theory are: 1. There is a strong downward trend in the rate of major new discoveries The mining sector has been pouring billions of dollars into exploration over the past decade but world-class gold discoveries are not being made at a rate seen in the past. The low hanging fruit have been picked. 2. Increasing development constraints delay or kill new mine construction Environmental and political regulatory regimes around the world are making new mine financing and development increasingly difficult and potentially uneconomic. 3. Very large gold deposits, defined as +10 million ounces, are quite rare Only 15% of all gold deposits are classified as 'very large'. This is a normal population considering a statistical evaluation of nature's abundance of mineral deposits of different types including gold. 4. Average grades of largest gold mines in operation are decreasing Over the past 15 years, mine grades for the top mines have dropped from an average of 4.5 g/t to 1.1 g/t Au. Modern enhanced recovery techniques are allowing for the economic extraction of these lower grade ores, however, development of even lower grade deposits without a significant and sustained increase in the price of gold will not be profitable. 5. Grades of the remaining major undeveloped gold deposits are 30% lower than mines currently in operation One of the reasons that the current portfolio of gold deposits remains undeveloped is largely due to lower than average grades. If grades of these remaining reserves were highly economic, they would have been developed already. These lower grade reserves and resources will have to wait for higher sustained gold prices or new recovery technologies that would make them economic.

Mineral deposit types are usually named or described on the basis of a classification scheme using defined criteria. However, the determination of what type a deposit belongs to is not a casual affair but based on a combination of field observations and rigorous laboratory studies that often include mineralogical examination of the ores, stable isotope geochemistry and fluid inclusion study. There are many ways of grouping mineral deposits, but some geological criteria have been accepted and used for classification including; (1) metal content (commodity); (2) shape or form of deposits (morphology); (3) host rock association; (4) ore forming processes, (5) conditions of deposition (temperature, pressure), (6) tectonic setting, and (7) origin (genesis). Table 1.1 summarizes the important classification schemes and identified groupings. Among these classifications, the most widely accepted by economic geologists is the genetic classification which is broadly based on the supposed origin of the mineral deposits and ore-forming processes. The genetic types include deposits associated with magmatic, hydrothermal, sedimentary, metamorphic and surficial ore-forming processes as described in earlier sections of this book (Table 2.10).

The recently-discovered nickel mineralization in Dangoma, Kaduna State, along the southern margin of the Jos Plateau is rare and unique because it contains high grade native nickel that occurs as metallic pellets or "balls" about 0.1 to 5 mm in size, and dispersed within a deeply weathered regolith overlying a serpentinized ultramafic host rock. The deposit is described as "world class and highly unusual"-a type that has not been previously reported. Field investigation shows that the nickel mineralization is localized within a serpentinite body that occurs within the Precambrian basement complex of north-central Nigeria. The basement rocks comprise of Archean migmatites and gneisses, and Proterozoic metasediments and meta-ultramafites that were intruded by Pan-African granitoids and pegmatites around 500 my ago. The Dangoma serpentine, like other similar rocks within the Proterozoic schist belts are slivers emplaced along transcurrent and associated fault systems. The native nickel occurs as a residual deposit within a thick and deeply weathered regolith in which the native Ni occurs probably as awaruite (Ni3Fe) containing an average of 94%% Ni with Fe, and traces of Cu, Zn, Pb and Co. The origin of this unique deposit is attributed to a combination of initial serpentinization of an ultramafic intrusive rock that produced a hydrated, highly reducing and low sulfur fugacity environment in which Ni in primary olivine was remobilized to form blebs of Ni-Fe alloy that grew in size with increased temperature during progressive low-grade metamorphism. The unique roundness of the Ni pellets as "balls" is intriguing, and probably occurred during lateritic weathering and supergene remobilization within an area undergoing regional tectonic uplift.

The study area is located in the east of Bam city and in the southern part of Lut block. In order to investigate the amount and behavior of uranium and associated elements in an area of ​​10 square kilometers, 616 lithogeochemical samples were taken and sent to the Labustre Laboratory of Australia for ICP-MS analysis. Various statistical studies such as correlation coefficient analysis, cluster analysis and factor analysis have led to the identification of two types of geochemical assemblages associated with the presence of uranium in the rocks of the region, which are assemblages associated with acidic rocks and altered (argillic) intermediate including UW-As- Mo-S-Cu-Ag and related igneous rock assemblages including U-Ni-V-Ag-Co-W-Mo-Cr-Cu-S. Also, four groups of elements due to their geochemical correlation with uranium can be considered, which are: Rare earth elements: Ce, La, Y Polymetallic elements: As, Sb, Ba, Cu, Pb, Zn, Mn, Fe, Se Sr, Elements related to acidic volcanoes: Be, Mo, W, Zr Elements related to mafic magmatic activities: Co, Cr, Ni, V. Based on the study of geochemical anomaly maps of uranium tracer elements in the region, the elements Mo, W, As, Sb, Tl, Pb, Be and Cd have an enrichment trend consistent with uranium anomalies and are the first priority among trace elements. Adapting the uranium alignment curves on the geological map of the region, it can be seen that the mentioned anomalies correspond to the fragmentation zones and fault trends of the region and correspond to rhyolite tuff units (dacitof, rhyolite tuffs, iron ore, sedimentary argon units And in some places are associated with carbonate alteration and manganese mineralization.

Resumo O Complexo de Ferro de Moncorvo localiza-se na região nordeste de Portugal e na última década voltou a ser o foco de interesse de algumas empresas mineiras. Este jazigo é formado por sedimentos de plataforma enriquecidos em ferro pertencentes a uma sequência do Paleozóico Inferior sujeita a deformação e metamorfismo de baixo grau durante a Orogenia Varisca. Vários estudos sobre caracterização mineralógica e petrográfica foram realizados procurando estabelecer um sistema de classificação dos diferentes tipos de minério presentes no jazigo. Este estudo apresenta uma comparação entre os tipos de minérios de ferro da serra de Reboredo e Mua com o minério de ferro presente no flanco sul do sinclinal de Moncorvo. Por fim conclui-se que os minérios presentes do flanco sul são muito semelhantes aos minérios do tipo magnetítico/martítico presentes no flanco norte do sinclinal de Moncorvo. Palavras-chave: minério de ferro, Moncorvo, magnetite, martite Abstract The Moncorvo Iron Complex is located in the northeastern region of Portugal and, in the last decade, it became again the focus of interest of some mining companies. This deposit is hosted in Lower Paleozoic sediments enriched in iron and deposited in a marine platform. Deformation and low grade metamorphism affected the sedimentary sequence during the Variscan Orogeny. Several studies were developed trying to establish a classification system for the different ore types based on the mineralogical and petrographic characteristics present in the deposit. This study presents a comparison between the iron ore from the Reboredo and Mua ridges with the iron ore located in the southern limb of the Moncorvo syncline. Lastly it is possible to conclude that the iron ores from the southern limb area are very similar to the magnetite/martite ore types present on the northern limb of the Moncorvo syncline.

Understanding how mineral deposits are formed (ore genesis) is the "centerpiece" of economic geology. Due to the facts that most mineral deposits were formed long time ago and at great depths below the surface; it has been quite difficult to decipher all the processes involved in their formation. However, it is well established that "ore-forming fluids" are the main agents of ore deposition, and that most ore deposits were formed when ore fluids from various sources, transport, concentrate and precipitate metals in abundance mostly as sulfides and oxides within favorable geological environments. Ore-forming processes are the offshoots of geological processes that form and modify rocks. These processes are classified and described in five groups: magmatic, hydrothermal, metamorphic, sedimentary and surficial.

Host rocks of the iron oxide- apatite deposits (IOA) in the Bafgh mining district are composed of plutonic and volcanic rocks that originated from enriched mantle. The high amount of LREE/HREE ratio in these deposits indicates a progressive magmatic differentiation. Study of rocks and minerals of the iron ore deposits in Central Iran combined with the results of other researchers related to the rare earth elements in this region showed that monazite, xenotime and allanite are the most abundant REE-bearing minerals. These minerals are commonly found as fluid inclusions within the apatites however, allanite occurs as an automorphous and zoned crystal in syenites of the Ghoghart mine. Both monazite and allanite minerals contain La, Nd, and Ce but monazite is more abundant than allanite. The xenotime, britholite, synchysite and bastnasite minerals are less common. The distribution model of REE in Esfordi ,Choghart and Chadormalu deposits is similar to Kiruna in Sweden, indicating the same origin of their formation. The only difference is the higher amount of total LREE in Choghart and Esfordi ores in comparison to lesser quantity in Kiruna’s but the host rocks are poor in these elements.

Keywords : Rare earth elements, iron oxide- apatite deposits, Bafgh, Central Iran

The main aim of this paper is to review and compare the various geochemical assessments that have been carried out on the Nigerian phosphates with a view to encourage local and international investors to develop and exploit these deposits. Nigeria is located on latitude 100 North and longitude 80 East surrounded in the north by Niger and Chad and in the east by Cameroun and in the west by Benin Republic. The comparative geochemical assessments of the Nigerian phosphates show that they compare favourably with deposits from Togo, Morocco, Jordan, USA, Algeria, China, etc. With the current economic reforms and investment incentives in Nigeria, interested investors are highly welcome to take advantage of developing these deposits

The main aim of this paper is to review and compare the various geochemical assessments that have been carried out on the Nigerian phosphates with a view to encourage local and international investors to develop and exploit these deposits. Nigeria is located on latitude 100 North and longitude 80 East surrounded in the north by Niger and Chad and in the east by Cameroun and in the west by Benin Republic. The comparative geochemical assessments of the Nigerian phosphates show that they compare favourably with deposits from Togo, Morocco, Jordan, USA, Algeria, China, etc. With the current economic reforms and investment incentives in Nigeria, interested investors are highly welcome to take advantage of developing these deposits