Tons Of Copper Research Articles

Maritime Archaeology and Trans-Oceanic Trade: A Case Study of the Oranjemund Shipwreck Cargo, Namibia

Routine sand dredging for alluvial diamonds at Oranjemund on the southern coast of Namibia exposed remnants of a long forgotten Portuguese merchant ship believed to have wrecked in the 1530s. The rescue excavations yielded over 40 tons of cargo consisting of thousands of gold and silver coins, tons of copper and lead ingots, and large quantities of ivory together with food refuse, part of personal possessions and the superstructure of the ship. This paper discusses the cargo from the shipwreck. The varying provenances show that overland inter-and intra-regional networks fed into the maritime trade between Europe and the Indian sub-continent. As such, the wreck is a lens through which we can view what was happening on the seas as well as on land. Finally we consider wider issues raised by this discovery relating to the protection and management of such material wherever it may be found in future.

Biooxidation of ferrous iron and sulphide at low temperatures: Implications on acid mine drainage and bioleaching of sulphide minerals

Chilean copper production has been growing in the last 20 years reaching an annual production of 5,557,000 tons of Cu in 2007. For each ton of copper produced, about 200 tons of sterile and low grade ore and 100 tons of tailings are discharged in the environment. Most of these wastes contain significant amounts of sulphide minerals, mainly pyrite, that once submitted to weathering, may produce acid mine drainage. On the other hand, copper high prices raised the interest for processing the low grade ore deposited in large dumps by leaching. An important part of these mining wastes and low grade ores is located in the Andes, where the mean temperature is usually ∼ 5 °C or less. The rate at which bioleaching reactions occur is directly related to the temperature at which the microorganisms (bacteria and archaea) develop. A temperature decrease causes both a decrease on the chemical reactions rates and a decrease or inhibition on microbial growth. The results for microorganism isolation from an old tailing deposit, exposed at low temperatures (5 °C) during most of the winter are presented in this work. Initially the isolated microorganisms showed a limited capacity in oxidizing Fe(II) sulfate (3 g L − 1) at pH 1.6, and tetrathionate (0.01 M), with an initial pH of 4.0 at 5 °C. However, after successive cultures, microorganisms showed a low capacity to oxidize both substrates, as well as the sulphide contained in the tailing samples. The terminal Restriction Fragment Length Polymorphism (tRFLP) of the isolated cells grown in basal medium containing Fe(II) showed a nearly pure culture of Acidithiobacillus ferrooxidans. The present study indicates that, even at very low temperatures, microorganisms play an important role in the acid mine drainage generation and also during the oxidation and leaching of sulphide ores.

A 2000-year record of copper pollution in South China Sea derived from seabird excrements: a potential indicator for copper production and civilization of China

In the Chinese feudal era, copper was widely used in coinage and weapons, and its production was coupled with political stability and economic prosperity. In the smelting process, copper was released into the environment and accumulated in the food web, and it became enriched in animal tissues and in seabird droppings. Here we report a 2000-year record of copper in red-footed booby excrement from Dongdao Island, South China Sea. There exists a striking correlation between the copper content in the seabird excrements and the ancient copper production of China for past two millennia. The increased Cu content corresponds to the flourishing times of dynasties, such as the Tang and Sung Dynasties, and declines in Cu content correspond with dynastic declines. Even some brief (decadal) wars and calamities, such as the Anshi Rebellion in AD 755–763 and the Taiping Heavenly Kingdom in AD 1851–1864, were recorded in the copper content profile. We established an approximate function to model the quantitative relationship between the copper content in the seabird excrement and the ancient copper production. We estimate that a total of ~14 million tons of copper was produced during the past two millennia in China. Among the 14 million tons of copper, about 0.65 million tons was released into the atmosphere.

Early copper smelting at Itziparátzico, Mexico

Archaeological fieldwork and archaeometallurgical analysis have identified a Late Postclassic regional centre of copper production in western Mexico. The total output from a single unit of production at the site of Itziparátzico is an estimated ten tons of copper and nearly forty tons of slag over the lifetime of the installation. It is argued that this smelting was based on slag-tapping furnaces, a technology previously unknown from Mesoamerican archaeological sites. The smelting site is in dense woodland with ample fuel supply, some 125 km from the next mining area with documented contemporary ore extraction; the copper produced would have been passed on to the capital, another 60 km away, for further distribution and working. The scale of production at Itziparátzico indicates that copper smelting was done by part-time specialists embedded in a predominantly agricultural economy, and formed part of a centrally organized network of mining, smelting and processing of copper to supply the Tarascan state.

Bacterial Oxidation of Ferrous Iron and RISCs at Low Temperatures: Their Effect on Acid Mine Drainage and Bioleaching of Sulphide Minerals

Chilean copper production has been growing in the last 20 years reaching an annual production of 5,557,000 tons of Cu in 2007. For each ton of copper produced, about 200 tons of sterile and low grade ore and 100 tons of tailings are discharged in the environment. Most of these wastes contain significant amounts of sulphide minerals, mainly pyrite, and once submitted to weathering, may produce acid mine drainage. On the other hand, the high price of copper raised the interest for processing by leaching the low grade ore deposited in large dumps. An important part of these mining wastes and low grade ores is located in the Andes, where the mean temperature is usually ~5°C or less. The rate at which bioleaching reactions occur is directly related to the temperature at which the microorganisms (bacteria and archaea) develop. A temperature decrease causes both a decrease of the rate of the involved chemical reactions and a decrease or inhibition of microbial growth. In this work we present the results of the isolation of microorganisms from an old tailing deposit, exposed at low temperatures (5oC) during most of the winter. The isolated microorganisms initially showed a low capacity to oxidize 3g/L Fe(II) sulfate at pH 1.6, and tetrathionate 0.01 M, with an initial pH 4 both at 5oC. However, after successive cultures, microorganisms showed a slow capacity to oxidize both substrates, as well as the sulphide contained in the tailings samples. The terminal Restriction Fragment Length Polymorphism (tRFLP) of the isolated cells grown in basal medium containing Fe(II) showed a nearly pure culture of Acidithiobacillus ferrooxidans. The present study indicates that, even at very low temperatures, microorganisms play an important role in the generation of acid mine drainage and in the oxidation and leaching of sulphide ores.

Modelling waste generation by the telecom sector in Nigeria: the grey side of the impressive outing

Since the introduction of digital mobile technology into Nigeria in 2001, there has been a phenomenal improvement in mobile subscription, service delivery and in the overall penetration of mobile telecommunication into rural areas in the country. For instance, the country's teledensity increased from less than 1% in 2001 to about 25% in 2006 - an increase of more than 3000%. The aim of this paper is to predict improvements in telephone penetration and waste generation by the Nigerian telecommunications sector. This was achieved by regression analysis of available data on telephone subscription in the country. Our estimations indicate that an average of 3 million phones will be retired annually in the country. Considering an economic phone life of 4 years, the over 32 million phones, (weight estimated at about 3200 tons) in use in 2006 would be at their end-of-life (EoL) by 2010. This volume of waste may contain up to 1800 tons of waste plastics, 15 tons of lead and 124 tons of copper. Our derived regression equation also indicates that mobile phone penetration in the country would be about 40% by 2010. This implies that over 55 million mobile phones would be in use by 2010. The grey side of this impressive statistics is that waste generation by the telecommunications sector will also follow this trend. This paper also highlights the need to introduce a framework for the effective management of waste from this sector considering the toxicity of some of the components of mobile phones and accessories and the prevailing inappropriate disposal practices for such potentially 'toxic' materials.

Power and Restructuring: Canada’s Coastal Society and Environment (review)

Reviewed by: Power and Restructuring: Canada’s Coastal Society and Environment Raymond Rogers Power and Restructuring: Canada’s Coastal Society and Environment. Edited by Peter R. SinclairRosemary E. Ommer. St John’s: Institute for Social and Economic Research, 2006. Pp. 336, illus., $31.95 As the introduction to this very interesting book on life on Canada’s east and west coasts states, ‘This is a book about power in [End Page 286] small places.’ By focusing on Aboriginal communities and coastal resource-based communities – the two most socially engineered groups in Canada – the series of case studies presented here highlight the deep colonial legacy that still exists in governmental agencies such as the Federal Department of Indian Affairs and the Federal Department of Fisheries and Oceans. As Sinclair and Ommer state, ‘Our purpose is to frame and understand the current context through processes of early development [of colonization and resource exploitation] and later restructuring [in the aftermath of collapse].’ As such, this book is part of a larger research project entitled Coasts under Stress: Restructuring and Social-Ecological Health, and the current book is one of three thematic collections that has come out of the research. The other two collections are entitled Making and Moving Knowledge and Resetting the Kitchen Table: Food Security, Culture, Health, and Resilience in Coastal Communities. In a chapter entitled ‘Colonial Territoriality: The Spatial Restructuring of Native Land and Fisheries on the Pacific Coast,’ Douglas Harris provides a graphic analysis of the way the ‘cartographic caging’ of Native people on reserves (and the extension of private property rights to settlers), and the creation of the category of the Aboriginal food fishery (and their exclusion from the extension of licensing in the commercial fishery) worked in conjunction to provide colonial regimes with the capability to enclose the commons so that the land-based and marine-based resources could be subjected to modern forces of production. Harris concludes that the ‘principal instrument of state control was the law’ as it carried out this process of twin marginalization of Aboriginal communities. A sample of quotations from the other case studies in section 1 of the book reflect similar patterns of domination and marginalization: • In the case of White Bay [nl], capitalists in the forestry sector used their power and influence to dominate the overall structure of the industry (Cadigan, 76). • A single mining company oversaw the province’s second largest regional centre [bc’s Anyox mine in the 1930s], which produced tons of poisonous chemicals, millions of tons of copper, and wealth for distant owners (Griffin, 82). • At the same time as settlement grew, missionaries on both coasts delivered Anglo-European ideas of health care infused with [End Page 287] colonial assumptions of the superiority of these practices and ideas (Kealey, Coombs, Turner, and Yeomans, 128). • The story of the past three decades also involves the successive elimination of species from the ecosystem, often by non-resident fishers, thus eroding the ability of Labrador communities to survive (Kennedy, 142). Is there an elected politician or a policy maker in the provincial or federal governments in any of these areas who will speak about these issues in this way? The authors of this book challenge the enclosure of discussion within the categories that have served the more powerful members of Canadian society: ‘Here we offer a new interdisciplinary state-society analysis that should make it easier to highlight those problematic aspects of restructuring that are obvious to coastal communities, but seldom appear on the bureaucratic radar screen’ (Tomblin, Ommer, and Sinclair, 276). Whereas section 1 of the book focuses on ‘power over’ (the capacity to modify, use, consume, or channel outcomes), section 2 focuses on the ‘power to’ (the social relations that are brought into play in response to the exercise of ‘power over’) (MacDonald, Neis, and Grzetic, 188). As neo-liberal initiatives increase poverty and shift demographics, supporters of such things as local schools find it necessary to ‘resist – with their actions and discourse – proposed changes that threaten them. The question remains as to how long the resisters can withstand the new language and its accompanying patterns of action and understanding’ (Harris, Riley, and Robinson, 231). Similar issues confront...

Assessing the long-run availability of copper

This study questions recent research [Gordon, R.B., Bertram, M., Graedel, T.E., 2006. Metal stocks and sustainability. Proc. Natl. Acad. USA 103(5), 1209–1214] that concludes that the world is likely to experience a growing scarcity of copper over this century. In particular, it focuses on the methodology used in this work that assumes the usable copper contained in the earth is a fixed amount. While the fixed-stock paradigm is intuitively appealing—after all the earth is finite so the amount of any commodity it contains must also be finite—and used with some frequency by others as well to assess long-run trends in the availability of non-renewable mineral resources, it is flawed and can lead to overly pessimistic as well as overly optimistic expectations. A more useful and appropriate approach, the opportunity-cost paradigm, assesses long-run trends in availability by real prices or alternative measures of what society has to give up or sacrifice to obtain another ton of copper or barrel of oil. This approach indicates that copper could conceivably become less scarce by the end of the century. Whether this will be the case or whether copper will be more scarce, however, depends on a number of factors, including the future course of technological change, whose influence no one can predict with any degree of certainty decades in advance.

Medical Geology: An Opportunity for the Future

Our environment is the entire web of geological and biological interactions that characterize the relationship between life and the planet Earth. Essential and toxic elements in bedrock or soils may become a direct risk for human and animal health and may be the underlying cause of both deficiency and toxicity. Some naturally occurring elements are necessary for our wellbeing, while others are detrimental to our health. Naturally occurring elements can have detrimental effects on health when ingested in increasing quantities. Metals have always existed and will forever exist, but we cannot avoid the fact that the health of human beings and animals is influenced by metals and other elements in the environment. Geological processes along with human activities of all kinds have redistributed these from sites where they are fairly harmless to places where they adversely affect humans and animals. Geology may appear far removed from human health. However, rocks are the source of all the naturally occurring chemical elements found on the Earth. Many elements in the right quantities are essential for plant, animal, and human health. Most of these elements enter the human body via food and water in the diet and through the air that we breathe. Through the weathering processes, rocks break down to form soils on which crops and animals that constitute the food supply are raised. Drinking water moves through rocks and soils as part of the hydrological cycle. Much of the dust and some of the gases present in the atmosphere are the result of geological processes. Hence, a direct link exists between geochemistry and health due to ingestion and inhalation of chemical elements. Volcanism and related igneous activities are the principal processes that bring elements to the surface from deep inside the Earth. For example, the volcano Pinatubo ejected in just over 2 d in June 1991, about 10 billion tonnes of magma and 20 million tonnes of SO2 and the resulting aerosols influenced the global climate for 3 y. This event alone introduced 800 000 tonnes of zinc, 600 000 tonnes of copper, and 1000 tonnes of cadmium to the surface environment. In addition to this, 30 000 tonnes of nickel, 550 000 tonnes of chromium, and 800 tonnes of mercury were also added to the Earth's surface environment. Volcanic eruptions redistribute some of the harmful elements, such as arsenic, beryllium, cadmium, mercury, lead, radon, and uranium, plus most of the remaining elements, many of which may have still undetermined biological effects. It is also important to realize that there are on average 60 subaerial volcanoes erupting on the surface of the Earth at any given time, releasing various elements into the environment. Submarine volcanism is even more significant than that at continental margins, and it has been conservatively estimated that there are at least 3000 vent fields on the midocean ridges (1). One interesting fact is that about 50% of SO2 is of natural origin, mainly from volcanoes, and the other 50% is from human sources. The naturally occurring elements are not distributed evenly across the surface of the Earth, and problems can arise when element abundances are too low (deficiency) or too high (toxicity). The inability of the environment to provide the correct chemical balance can lead to serious health problems. The links between environment and health are particularly important for subsistence populations that are heavily dependent on the local environment for their food supply. Approximately 25 of the naturally occurring elements are known to be essential to plant and animal life in trace amounts, including Ca, Mg, Fe, Co, Cu, Zn, P, N, S, Se, I, and Mo. On the other hand, an excess of these elements can cause toxicity problems. Some elements such as As, Cd, Pb, Hg, and Al have no or limited biological function and are generally toxic to humans. Many of these elements are known as trace elements because they generally occur in minute (,g kg-l or ppm) concentrations in most soils. Trace element deficiencies in crops and animals are therefore commonplace over large areas of the world, and mineral supplementation programs are widely practiced in agriculture. Trace element deficiencies generally lead to poor crop and animal growth and to reproductive disorders in animals. These problems often have the greatest impact on poor populations who can least afford nutritional interventions for their animals.

Copper metallurgy at the crossroads

Copper technology changed from the vertical to the horizontal furnace and from the roast reaction to converting towards the end of the last century. However, the horizontal furnace proved to be an inefficient and polluting reactor. As a result many attempts were made to replace it. In the past 50 years new successful melting processes were introduced on an industrial scale that were more energy efficient and less polluting. In addition, smelting and converting were conducted in a single reactor in which the concentrate was fed and the raw copper was produced. The standing problem in many countries, however, is marketing 3 tonnes of sulfuric acid per tonne of copper produced as well as emitting large amounts of excess SO2 in the atmosphere. Pressure hydrometallurgy offers the possibility of liberating the copper industry from SO2 problem. Heap leaching technology has become a gigantic operation. Combined with solvent extraction and electrowinning it contributes today to about 20% of copper production and is expected to grow. Pressure leaching offers the possibility of liberating the copper industry from SO2 problem. The technology is over hundred years old. It is applied for leaching a variety of ores and concentrates. Hydrothermal oxidation of sulfide concentrates has the enormous advantage of producing elemental sulfur, hence solving the SO2 and sulfuric acid problems found in smelters. Precipitation of metals such as nickel and cobalt under hydrothermal conditions has been used for over 50 years. It has the advantage of a compact plant but the disadvantage of producing ammonium sulfate as a co-product. In case of copper, however, precipitation takes place without the need of neutralizing the acid, which is a great advantage and could be an excellent substitute for electrowinning which is energy intensive and occupies extensive space. Recent advances in the engineering aspects of pressure equipment design open the door widely for increased application. .

Sulfur isotopic zonation in the Cadia district, southeastern Australia: exploration significance and implications for the genesis of alkalic porphyry gold–copper deposits

The alkalic porphyry gold–copper deposits of the Cadia district occur in the eastern Lachlan Fold Belt of New South Wales, Australia. The district comprises four porphyry deposits (Ridgeway, Cadia Quarry, Cadia Hill, and Cadia East) and two iron–copper–gold skarn deposits (Big Cadia and Little Cadia). Almost 1,000 tonnes of contained gold and more than four million tonnes of copper have been discovered in these systems, making Cadia the world’s largest known alkalic porphyry district, in terms of contained gold. Porphyry gold–copper ore at Cadia is associated with quartz monzonite intrusive complexes, and is hosted by central stockwork and sheeted quartz–sulfide–(carbonate) vein systems. The Cadia porphyry deposits are characterized by cores of potassic and/or calc–potassic alteration assemblages, and peripheral halos of propylitic alteration, with late-stage phyllic alteration mostly restricted to fault zones. Hematite dusting is an important component of the propylitic alteration assemblage, and has produced a distinctive reddening of feldspar minerals in the volcanic wall rocks around the mineralized centers. Sulfide mineralization is strongly zoned at Ridgeway and Cadia East, with bornite-rich cores surrounded by chalcopyrite-rich halos and peripheral zones of pyrite mineralization. The Cadia Hill and Cadia Quarry deposits have chalcopyrite-rich cores and pyrite-rich halos, and Cadia Hill contains a high-level bornite-rich zone. Distinctive sulfur isotopic zonation patterns have been identified at Ridgeway, Cadia Hill, and Cadia East. The deposit cores are characterized by low δ34Ssulfide values (−10 to −4‰), consistent with sulfide precipitation from an oxidized (sulfate-predominant) magmatic fluid at 450 to 400°C. Pyrite grains that occur in the propylitic alteration halos typically have δ34Ssulfide values near 0‰. There is a gradual increase in δ34Ssulfide values outwards from the deposit cores through the propylitic halos. Water–rock interaction during propylitic alteration caused magmatic sulfate reduction and concomitant oxidation of ferrous iron-bearing minerals, resulting in enrichment of 34S in pyrite and also producing the distinctive reddened, hematite-rich alteration halos to the Cadia deposits. These results show that sulfur isotope analyses have potential applications in the exploration of alkalic porphyry-style deposits, with zones of depleted δ34Ssulfide values most prospective for high-grade mineralization.

English

The Mount Morgan Mine is a historic mine site located in Central Queensland, Australia. Between 1882 and 1981, a total of 7.6 million ounces of gold and 360,000 tonnes of copper were extracted using underground and later open mining methods. The mine closed in 1990 after the re-treatment of 28 Mt of tailings, which were placed into the open cut. Most of the mine waste is acid- generating and acidic runoff and seepage has heavily impacted portions of the adjacent Dee River. A groundwater flow model was developed for the Mount Morgan mine site to evaluate current seepage conditions and assess closure options. The calibrated groundwater flow model indicates that the backfilled (and flooded) Open Cut/Sandstone Gully represents the largest single source of ARD seepage (8.0 L/s) on the site with tailings impoundments representing important secondary sources of seepage. An estimated 80% of all seepage is collected in a seepage interception system (SIS). The remaining 20% (or ~3 L/s) of ARD impacted seepage by-passes the SIS and enters the Dee River and underlying aquifer. The model predicts that seepage from the open cut would increase exponentially with a further increase in the water level in the open cut. The model suggests that a grout curtain or sealing the upstream side of Sandstone Gully Dam using a blanket of low permeability tailings would reduce seepage out of the open cut by about 40%. The amount of seepage reduction in response to placing a dry cover system onto mine waste (tailings and mine rock) is predicted to vary significantly across the site. The modeling results suggest that a combination of rehabilitation measures (including the placement of dry cover system and measures to control seepage out of the flooded Open Cut/Sandstone Gully) will be required to effectively control seepage at Mount Morgan. The calibrated groundwater flow model is currently being used to assess the effects of different closure scenarios (e.g. cover placement versus full relocation) on seepage rates and loading to the Dee River.

Assessing the recycling efficiency of copper from end-of-life products in Western Europe

Recognizing that the recycling of copper and its alloying elements is often not well documented or fully understood, this paper quantifies the end-of-life recycling efficiency rate of copper using the copper flow model developed by the International Copper Study Group (ICSG). The model is complemented by results from a flow study for Western Europe in 1999. The ICSG model is based on a simultaneous use of a “Lifetime Approach” (based on historical end use data and average product lifetimes), an “End-of-Life Approach” (based on reported, measured or estimated end-of-life product flows) and a “Scrap Balance Approach (based on reported scrap use data). The “Lifetime Approach” predicts a copper reservoir in use of ∼78 million tonnes of copper and alloys for Western Europe. For 1999, it was estimated that the copper scrap availability and the old scrap recovery amounted to ∼2.7 million tonnes and ∼1.6 million tonnes of copper and alloys, respectively. The corresponding end-of-life recycling efficiency rate for end-of-life copper and copper alloy products in Western Europe in 1999 was estimated to be around 63% in the end-of-life approach, 64% in the lifetime approach, and 67% according to the scrap balance approach excluding outflows to other metal loops, and 69%, 70%, and 73%, respectively, including all identified outflows to other metal recycling loops.

Cypress Beams, Kufic Script, and Cut Stone: Rebuilding the Master Narrative of European History

In the year 769 a crisis appeared likely to engulf the Japanese imperial court at Nara. The empress Shotoku, aged fifty-two and childless, indeed never married, gave many signs that she intended to appoint a Buddhist priest named Dokyo as her successor. A noted faith healer, Dokyo was credited with curing the empress of a serious illness, for which she rewarded him with a succession of high offices in the imperial bureaucracy. That he was looked upon with favor by the empress was thus no secret, but there may have been more to their relationship than a magical cure and political rewards. One source from a few decades later says flatly that the two of them shared the same pillow. Dokyo had, in any case, arrived almost to the pinnacle of Japanese power, and yet there stood between him and the very top the inescapable fact that he was a commoner.1 Apart from any personal feelings for Dokyo, Shotoku had a long history of favoring the progress of Buddhism in her country. In this she was following the inclinations and policies of her father, Emperor Shomu, who, for example, decreed that every province must build and maintain an official Buddhist temple, where ceremonies would be carried out on a regular basis and where statues and sutras would be kept and accorded due honor. It was Shomu, moreover, who launched the project for erecting a massive gilded bronze statue of Buddha; its construction consumed over three hundred tons of copper and sixteen tons of gold. The temple enclosing it is the world's largest wooden structure. Before the statue was com pleted, though, Shomu abdicated in favor of his daughter in order to pursue his desire to become a Buddhist priest. She took the name Koken at the start of what turned out to be for her the first of two reigns, and she issued an edict declaring the name of the new era to be Heavenly Peace and Victorious Buddhism. Within a few years the great statue was completed, and she had it dedicated in what is

Geochemistry and microbiology of an impounded subterranean acidic water body at Mynydd Parys, Anglesey, Wales

ABSTRACTAcidic, metal‐rich water that had accumulated within two abandoned, adjacent copper mines in north Wales was removed to prevent its possible catastrophic release. About 274 000 m3 of acidic (pH ∼2.4) mine water was pumped out of the mines over a 14‐week period. Concentrations of dissolved species (iron, sulfate, aluminium, copper, manganese and zinc) increased as water at lower depths within the mines was accessed. The discharged water flowed through a small wetland area, reaching the sea about 3 km north of the mine site. Analysis of the water at three sampling stations revealed that there was very little removal of aluminium and most of the heavy metals present except (ferrous) iron, which was partially removed as a result of oxidation and hydrolysis of the resulting ferric iron. The dominant bacterium in the subterranean mine water, which was essentially devoid of oxygen, was the iron‐ and sulfur‐oxidizer Acidithiobacillus ferrooxidans. The microbial populations in the pumped mine water were monitored using combined cultivation‐dependent (isolation on solid media) and cultivation‐independent (terminal restriction fragment length polymorphism and clone library) techniques. Other bacteria detected in the mine water included other iron‐oxidizers (Leptospirillum spp., ‘Ferrimicrobium acidiphilum’ and Gallionella‐like organisms) and heterotrophic acidophiles (Acidiphilium, Acidisphaera and Acidobacterium). Archaeal clones were also detected; most of these were related to methanogens. Owing to the absence of an effective remediation strategy, an estimated 7.5 tonnes of copper, 3.1 tonnes of manganese, 14.8 tonnes of zinc and 15.3 tonnes of aluminium was discharged into the Irish Sea as a consequence of the dewatering of the mines.

Local, Regional, and Global Implications of Elemental Mercury in Metal (Copper, Silver, Gold, and Zinc) Ores: Insights from Lake Superior Sediments

Anthropogenic inventories for copper (229 ± 89 ug/cm 2, N = 30), and mercury (470 ± 307 ng/cm 2, N = 25) in Lake Superior sediments are much greater than inventories in remote lakes (Cu 50 ± 31 ug/cm 2, Hg 64 ± 34 ng/cm 2, N = 16) that receive inputs largely from long-distance atmospheric sources. Whereas the absolute concentration of mercury in Lake Superior sediments is not high (80–110 ng/g), enrichment ratios along coastal margins indicate industrial sources. An example of previously unreported mining-related inputs comes from native copper mining on the Keweenaw Peninsula. Around the peninsula, sediment inventories for mercury, silver, and copper are highly correlated and can be traced back to shoreline tailing piles, smelters, and parent ores. Elemental mercury occurs as a natural amalgam or solid solution substitution in native metal (copper, silver, gold) deposits and associated gangue minerals (e.g., sphalerite, ZnS) at μg/g or higher concentrations. Native copper stamp mills discharged more than 364 million metric tons of “stamp sand” tailings, whereas copper smelters refined five million metric tons of copper, liberating together at least 42 metric tons of mercury. Release of trace mercury from Lake Superior mining deserves regional attention as preliminary estimates resemble EPA Region #9 patterns and could help explain the 4–7 fold sediment inventory discrepancies. We show that the Keweenaw situation is not unique geographically, as mineral-bound trace mercury is commonplace in U.S. and Canadian Greenstone Belts and of worldwide occurrence in precious (gold, silver) and massive base metal (copper, zinc) ore deposits.

Mercury as a useful pathfinder for the Chinkuashih enargite-gold deposits, Taiwan

The Chinkuashih is a group of dacite-related hydrothermal enargite-gold deposits of the Quaternary age, which produced 94 tons of gold and 119,101 tons of copper from 1895 to 1987. It has remaining reserves of 656 tons of gold with an average grade range of 1.5–3.5 g/ton of Au for all orebodies discovered. Mercury content in different media such as stream sediments, heavy minerals in stream sediments, soils, rocks/ores, and pyrite samples was analyzed by a gold–film mercury detector to evaluate whether mercury is a good pathfinder for these types of deposits at Chinkuashih. The gold film technique is more rapid and cheaper than the traditional fire assay or fire assay/ICP-MS gold and trace element analyses. Mercury in stream sediments and soils indicated the border zone of gold mineralization 12 km away from the center of mineralization at Chinkuashih. Mercury in heavy minerals of the stream sediments distinguished the intermediate zone with gold veins and gold/gold–copper breccia pipes from the core or inner zone with the gold–copper zone. It has been found that contours of 1000 or 500 ppb Hg of soil samples can delineate the outcropping gold orebodies. The gold ores generally contain 1000 ppb or more Hg.

Mine size and the structure of costs

The number of operating mines has fallen sharply for most mineral products, and the average size of mine risen, with the changes gathering momentum during the 1990s. The paper looks at trends in copper, zinc and gold, and then explores the relationship between size and unit costs in copper mining, separately for underground and open-pit mines, in order to ascertain the existence and importance of economies of scale. Changes in mine size have been accompanied by major technological and geographical shifts. There is only a weak relationship between the scale of mines and overall unit costs per tonne of copper produced. The paper discusses the data and explores some of the reasons.

The Donoso copper-rich, tourmaline-bearing breccia pipe in central Chile: petrologic, fluid inclusion and stable isotope evidence for an origin from magmatic fluids

The copper-rich, tourmaline-bearing Donoso breccia pipe is one among more than 15 different mineralized breccias in the giant (>50 million metric tonnes of copper) Miocene and Pliocene Rio Blanco-Los Bronces copper deposit in the high Andes of central Chile. This breccia pipe, bracketed in age between 5.2 and 4.9 Ma, has dimensions of 500 by 700 m at the current surface 3,670 m above sea level. Its roots have yet to be encountered, and it is >300 m in diameter at the depth of the deepest drill holes. The Donoso breccia is, for the most part, monolithic, containing clasts of the equigranular quartz monzonite pluton which hosts the pipe. It is matrix supported, with between 5 and 25% of the total rock volume consisting of breccia-matrix minerals, which include tourmaline, quartz, chalcopyrite, pyrite, specularite, and lesser amounts of bornite and anhydrite. An open pit mine, centered on this breccia pipe, has a current production of 50,000 tonnes of ore per day at an average grade of 1.2% copper, and copper grade in the breccia matrix is significantly higher. Measured δ18O for tourmaline and quartz from the matrix of the Donoso breccia at different levels of the pipe range from +6.9 to +12.0‰, and measured δD in tourmaline ranges from –73 to –95‰. Temperatures of crystallization of these minerals, as determined by the highest homogenization temperatures of highly saline fluid inclusions, range from 400 to >690°C. When corrected for these temperatures, the stable isotope data indicate that fluids from which these breccia-matrix minerals precipitated were magmatic, with δ18O between +5.6 to +9.1‰ and δD between –51 to –80‰. These isotopic data preclude participation of a significant amount of meteoric water in the formation of the Donoso breccia. They support a model in which brecciation is caused by expansion of magmatic fluids exsolved from a cooling pluton, and breccia-matrix minerals, including copper sulfides, precipitated from the same magmatic fluids responsible for brecciation. Sericitic alteration of clasts in the breccia was also caused by these magmatic fluids. Different types of fluid inclusions imply that several different magmatic fluids were involved in formation of the Donoso breccia. These include high-temperature, highly saline, non-boiling fluids, trapped in inclusions that homogenize by halite dissolution, which probably exsolved from a magma cooling under relatively high (>1 kbar) lithostatic pressure conditions, consistent with geologic constraints. Other high-temperature, highly saline fluids are trapped in inclusions that homogenize by vapor-bubble disappearance and are spatially associated with vapor-rich inclusions, suggesting either phase separation (boiling) or simultaneous separation of immiscible brine and vapor from a magma cooling at lower hydrostatic pressure conditions. Both types of high-temperature, highly saline fluids circulated intermittently, as pressure fluctuated between lithostatic and hydrostatic conditions because of episodes of sealing and rebrecciation.

Influence of Gelatin on Deposit Morphology During Copper Electrorefining Using Scaled Industrial Cells

This paper discusses the effect of Gelatin (G) on cathode quality during copper electrorefining. Binary system Gelatin-Chloride ions (G-Cl-) and ternary system Thiourea-Gelatin-Chloride ions (TU-G-Cl-) have been investigated using scaled industrial cells and laboratory cells. Concentration of Clwas 40 mg L-1 and temperature 65 °C. In the pilot plant, current densities ranged between 200 and 400 A m-2, Gelatin concentration from 50 to 300 grams per ton of copper produced (g t-1) and Thiourea from 20 to 60 g t-1. Gelatin influences the polarization curves, the deposit morphology (roughness and nodule formation), the crystal structure (columnar or pyramidal) and the copper grain type (round or field oriented). Addition of Gelatin increases cathodic polarization but does not always lead to nodule formation. For the binary system, the cathode surface smoothness is acceptable but edge quality deteriorates as current density increases. In the ternary TU-G-Cl- system, surface smoothness and edge quality are greatly improved while copper growth structure is modified to produce a dense cathodic deposit. However, nodules, dendrites and big porosities appear randomly if G/TU ratio is not appropriate. The best cathodes were obtained when this ratio was higher than 0.8 but lower than 1.7.Cet article traite de l’influence de la Gélatine (G) lors de l’électroraffinage du cuivre. Le système binaire Gelatin-ions chlore (G-Cl-) ainsi que le système ternaire Thiourée-Gélatine-ions chlore (TUG- Cl-) ont été étudiés en utilisant des cellules industrielles réduites et des cellules de laboratoire. La concentration des ions Cl- est 40 mg L-1 et la température 65 °C. Dans les cellules pilotes, la densité de courant varie de 200 à 400 A m-2. La concentration en Gélatine varie de 50 à 300 grammes par tonne de cuivre produite (g t-1) et celle de la Thiourée de 20 à 60 g t-1. La teneur en Gélatine influence la courbe de polarisation, la morphologie du dépôt (rugosité et nodulation), la structure des cristaux (colonnaire et pyramidale) et la structure des grains de cuivre (round ou orienté). L’addition de Gélatine augmente la polarisation cathodique mais ne conduit pas forcément à la nodulation. Pour le système binaire, la qualité de la surface des cathodes est acceptable quoique les bords se détériorent avec l’augmentation de la densité de courant. Dans le système ternaire, la finesse de la surface et la qualité des bords sont grandement améliorées. La structure de croissance du cuivre est également modifiée et assure un dépôt dense. Cependant, des nodules, des dendrites et de grosses porosités apparaissent lorsque le rapport G/TU n’est pas approprié. Les meilleures cathodes ont été obtenues lorsque ce rapport est plus grand que 0.8 mais inférieur à 1.7