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The Modified Zincex® Process, developed by Técnicas Reunidas, is highly flexible dealing with a wide range of pregnant leach solutions. No matter if those solutions are produced from primary or secondary raw materials, and/or are based on conventional leaching, pressure leaching, heap leaching or bio leaching the result is always high-purity zinc product. The zinc solvent extraction unit within the process is a very effective barrier for impurities and a buffer for the composition of the pregnant liquor. This unit achieves an extremely pure aqueous extract that can be converted into different final products. All of them are characterized by fulfilling the highest purity standards. Also, there is the possibility to adapt the global process to a wide range of pregnant liquor compositions and various production capacities up to a zinc production limit over 150 000 t/a with a single solvent extraction plant.

Jan 1, 2002

Laboratory and pilot plant investigations aimed at recovering gold as an electroformed sheet from gold eluate and gold leach solutions and slurries are discussed. The electrolytic test work undertaken makes use of high surface area electrodes, in particular nickel-chrome foam metal and activated carbon, as well as ultrasonic activation. The process involves initial gold electrowinning (or adsorption onto activated carbon), followed by gold electroforming, both operations being carried out in a specially designed reactor. The pilot plant work mainly involved the treatment of gold eluate solutions from a South African gold mine containing 600 mg/L Au: some tests were also carried out on gold leach solutions containing 6 mg/L Au. In the former case, very efficient gold extraction onto the foam metal cathode was achieved using electrolysis combined with ultrasonics. The polarity of the gold-loaded cathode was then reversed and, using a replacement electroforming electrolyte, gold was electroformed in situ onto a polished stainless steel mandrel, from which gold sheet was subsequently removed. In the case of leach solutions, pilot plant tests confirmed laboratory findings that in the presence of calcium (resulting from the lime used during the leaching process) no electrowinning is possible. Laboratory tests showed, however, that when sodium (in the form of NaOH or Na2CO3) is added to the leach solution, electrowinning can indeed take place. Alternatively, if a special activated carbon electrode is used (without current), the non-ionic calcium aurocyanide complex is adsorbed on to the activated carbon. When a gold-loaded activated carbon electrode is made anodic in a gold electroforming electrolyte, gold electroforming is feasible, although the efficiency is very low. The possible implications of these developments for gold recovery are further examined.

Jan 1, 2007

By Peter A. Adcock, Rob Fraser

Interest in monitoring nucleation overpotential in electrometallurgical processes dates back some 40 years or more. Conversely, remarkable progress has been made in recent years on describing in detail the processes involved in the formation of thin films by electrodeposition. The newer body of work underscores a need for greater clarity in speaking about the role of nucleation and in the acquisition and interpretation of nucleation overpotential measurements – the aim of this paper. In electrometallurgy, it is generally desirable to form deposits that remain smooth, compact, and relatively fine-grained while the deposit grows to a thickness on the order of 5-10 mm, about 100 times thicker than technological thin films. Hence, we distinguish two kinds of nucleation that can result in formation of new grains:- (1) initial nucleation (onto the substrate surface) of islands that coalesce into growing deposit, and (2) ongoing nucleation of new grains on the deposit surface long after the substrate has been covered and ceases to have a direct influence. Nucleation overpotential of the first type should be measured on an electrode surface truly representative of a real industrial substrate. The second type requires judicious choice of electrode material – an “ideal foreign substrate”. In general neither the industrial substrate nor native metal to be deposited is suitable for measurement of the second type of nucleation overpotential, because of interference by other processes. For the future, clear terminology is needed to distinguish these two types of nucleation potential. The second is the one for which the type of plot dubbed by Moats and Derrick as an “Adcock plot” and by us as a “Kerby-Adcock plot” was first conceived and correlated with relatively thick zinc electrodeposits. The data of Moats and Derrick showing trends for copper electrodeposition on stainless steel and on copper electrodes are interpreted within this framework.

Jan 1, 2016

By R. J. Hundhausen

"INTRODUCTION Preliminary examination of the Blue Ledge mine was made by O. H. Metzger, a Bureau of Mines engineer, in May 1943. A result of his recommendations; a Bureau of Mines sampling and exploration project was begun by J. R. Reynolds in October 1943 and continued to December when it was recessed for the winter. The project was resumed by the auther in May 1944 and was completed in November 1944. The Federal Geological Survey 3/ assisted by mapping the geology of the mine and logging the diamond-drill cores obtained from the Bureau's exploration Company maps, diamond-drill-hole records, several reports, and other data on the property were made available to the Bureau by D. C. Brown, of Towne Securities Corporation, owner of the Blue Ledge group of claims. E. A. White, general manager of the Tacoma Smelter of the American Smelting & Refining Co., supplied statistics for all ore that has been purchased from the Blue Ledge mine by his company."

Oct 1, 1947

Research on Reduction-Magnetic Separation of Bayan Obo Ore

Sep 13, 2010

By George M. Fowler

DURING 1937 the subject of mining geology was probably given more attention and more mining geologists were usefully employed than at any previous time. Of the many contributing factors the most important were: (1) a higher degree of prosperity in many countries, (2) a. better understanding of geologic phenomena, and (3) the apparently diminishing reserves of several important minerals. Mining companies have come to look upon geology with a growing appreciation of its aid in the more effective exploration and exploitation of mineral deposits. Most of the larger and more active companies have one or more geologists permanently attached to their staffs and some have well organized and efficiently managed geological departments. Even the smaller companies, who feel they cannot afford to employ a geologist on a permanent basis, are seeking the advice of competent men in this field with increasing frequency. One of the most significant trends has been the growing tendency to base exploratory work on more thorough geologic studies instead of empirical "hunches,"on which so much off the work in the past has relied. Likewise, mining companies are apparently more willing to expend larger sums on the basis of geologic possibilities in a district.

Jan 1, 1938

The Subtropolis mine is a room-and-pillar mine extracting the Vanport Limestone near Petersburg, Ohio. In February 2018, mine management began implementing a heading reorientation to better control the negative effects of excessive levels of horizontal stress. The conditions in the headings improved, but as expected, stressrelated damage concentrated within crosscuts. The mine operator has worked to lessen the impact of the instabilities in the outby crosscuts by implementing several engineering controls. With the implementation of each control, conditions were monitored and analyzed using observational and measurement techniques including three-dimensional (3-D) LiDAR surveys.

Jan 7, 2020

By Rob Barber

This paper shares the experience of the Alberta Energy and Utilities Board (EUB) Field Surveillance Branch over the past few years in building relationships with Aboriginal communities. Our goal is to provide and encourage best practices that may benefit you and your organization and result in strong, mutually beneficial relationships with a focus on Aboriginal communities. Historical information provides insight that aids in establishing effective working relationships with Aboriginal communities. An important component is appreciation of the perspective of these communities, which is achieved through awareness training. The use of local Aboriginal resource people as part of the training is recommended. A plan that is supported by management and staff is essential and lays the foundation for successful relationships. However, the plan must be flexible enough to change as circumstances warrant. The concept of having local people in communities address local issues is essential. This ?grass roots? approach, combined with the goal of exceeding a community?s expectations with respect to addressing issues, will go a long way to establish trust and credibility. Measuring the effectiveness of this work is the final building block to complete the picture.

May 1, 2004

By Roger L. Williams

The Bureau of Mines investigated northern New Jersey as a potential future source of yttrium and the rare-earth elements. The studies, consisting of geophysical surveying, sampling, and exploratory drilling, began in the spring of 1959. A total of three and one-half months were spent in the field collecting data. Thirty-three deposits were investigated, of which five demonstrated some potential resources of yttrium and rare-earth minerals. Results indicate that the deposits examined do not contain quantities of yttrium and the rare-earth elements recoverable under present economic conditions. Detailed studies conducted at the Scrub Oaks mine, near Dover, N. J., delineated a yttrium and rare-earth-bearing zone within the magnetite-hematite ore body that represents a potential low-grade deposit. Beneficiation studies on this deposit indicate that a final product, averaging 31.3 percent rare-earth oxides including yttrium, could be produced through amine and fatty acid flotation procedures with 77 percent recovery. Two hundred and eighty-five feet of diamond drill core was obtained from exploration studies conducted at the Bemco prospect in Sussex County. The deposit averages 2.30 percent rare-earth oxides (including yttrium), 0.45 percent uranium and 0.24 percent thorium. Low-grade deposits were identified at the Canfield phosphat2 mine and the Tanners Brook Monazite placers in Morris County, and the Marble Mountain prospect in Warren County.

Jan 1, 1967

By Hamid-Reza Manouchehri

"Sustainability calls for maintenance, rational use and enhancement of natural resources as well as balance consideration of ecology, economy, and social justice. The challenges in mining industry call for a sustained global effort using the leverage of available technologies and emerging new technologies. The industry uses significant amount of energy with the highest portion in comminution. To conserve energy, attempts have been made to improve the efficiency of the conventional crushing and grinding equipment. Nevertheless, the new and energy efficient comminution technologies are favorable through a longer term strategy. Since crushers are more energy efficient than mills, it is logic to conduct part of milling, in the crushing stage. After years of research and development, Sandvik introduces a new crushing technology, VibroconeTM, to change traditional crushing concepts. The new crushing device is able to crush and grind particles with a higher reduction ratio, more than two fold, than that of conventional crushers. By implementation of the new technology, a suitable feed size for milling can be provided to conserve energy as well as media and liner consumption, to reduce milling circulating load or increase mill capacity. There are other benefits associated with this machine, one of them being providing a higher surface area. This paper discusses the performance of the machine and its applications for comminuting different ores."

Jan 1, 2014

By Deon van Tonder, Bert Van Hege

Comparison of various technologies for uranium recovery from sulphuric acid leach solutions shows that Resin-in-Pulp (RIP) and/or Solvent extraction (SX) based processing routes are usually cost effective (11). A combined RIP-SX recovery-purification route and a CCD-SX recovery-purification route were investigated and optimised. The design basis used for the investigation was a production rate of 200 kg/h U3O8 over a solution concentration range of 40 to 1500 mg/L U3O8. The OPEX for the RIP-SX processing route was found to be sensitive to the variation in uranium concentration in the leach liquor. One of the main drivers for this trend is the leach acid concentration. Conversely, the CAPEX of the CCD-SX processing route was sensitive to the uranium concentration in the leach liquor. The leach acid concentration only affected the OPEX of the CCD-SX processing route modestly, as the bulk of the acid is recovered in a pre-leach circuit. Contrary to expectation, the effect of extractant loss assumptions on the overall processing route economics was found to be modest to insignificant. It should be noted that the CCD-SX processing route OPEX was more sensitive to extractant loss assumptions than the RIP-SX processing route OPEX. Economic optimum wash ratios were determined for the CCD-SX processing route and increased with leach concentration ? the increase in wash ratio was less than proportional. A 5-stage CCD configuration was found optimal over the concentration range investigated.

Jan 1, 2007

By T. Jason Hardell

The Victory Bridge project was contracted by the New Jersey Department of Transportation. The project included the construction of two 4000-ft precast segmental concrete bridges to replace the existing Victory Bridge that was built in the 1920's. The existing bridge was a swing span bridge that was in desperate need of replacement. The project was considered high priority due to the large maintenance costs to keep the swing span operating over the busy navigational channel. In March of 2003 construction began on the first bridge and by April of 2005 all of the segments were set for the second bridge. On September 5 of 2005 the second bridge was open to traffic. The total cost of the project was $110-million. The two new bridges required the construction of 24-eight foot and 32-six foot diameter-drilled shafts with rock sockets. All of the shafts were constructed in the tidal Raritan River working from barges. What will follow is a description of the construction techniques that were used to build these drilled shafts, the anticipated and unanticipated challenges that were encountered during the project, and the lessons learned.

Jan 1, 2005

By O. Matwijenko

"1. IntroductionThe Falconbridge Owl Creek open pit gold mine is located 17 km northeast of Timmins and 2.5 km west of the Kidd Creek metallurgical site. Diamond drilling first commenced in 1964 with open pit production commencing in 1982. Other operations within close proximity are the Canamax-Pamour Bell Creek Mine and the Falconbridge Hoyle Pond Mine.Since 1982, 1,216,000 tonnes assaying 4.5 g/t have been processed in six concentrators. This paper summarizes the metallurgy achieved with special emphasis on some of the unique problems encountered in the processing of this refractory ore.2. GeologyThe Owl Creek deposit, located 3 km north of the Porcupine-Destor fault is in easterly trending carbonaceously altered volcanic and sedimentary rocks. The deposit strikes east and dips steeply north.The ore body can be best described as a wedge shaped sandwich of volcanic basalt between the surrounding sedimentary greywacke. The north and south volcanic-sedimentary interfaces are marked by graphitic zones. The south graphitic contact is more continuous with its thickness varying from 5 m to 20 m as compared to 0.5 m to 3 m to the north. Quartz veins occur throughout the deposit with a predominant vein running along the south contact where it is characterized by numerous graphitic inclusions. Some veins carrying gold values intrude into the sediments in the north. With depth the sedimentary and volcanic zones taper while the quartz-graphitic zones appear to become more dominant."

Jan 1, 1988

By P J. Willems, B J. Junor

Blackwater Mine is in the central-southern Bowen Basin, immediately south of the township of Blackwater on the Capricorn Highway. The current open cut operation extracts coal from three main seams, designated Top, Middle and Lower, in the Late Permian Rangal Coal Measures cropping out on the eastern flank of the Comet Ridge. Complex geological structures, dominated by E-W normal faults and N-S reverse faults, have significant detrimental effects on coal mining operations. Historical exploration before 2010 involved several types of drilling only to understand structure, coal quality and washability. Hence, although drilling data was combined with limited pit mapping and observation, unknown structures were still often encountered during excavations and led to mining surprises. In 2010 BHP completed 200-line km of closely spaced 2D seismic survey to capture gross and detailed structures followed by fit for purpose structural drilling to confirm major structures in the northern part of the mine. In 2018 a high density 9.2 km2 3D seismic survey was completed in the southern part of the mine. Subsequently, a 17.2 km2 survey was completed in 2020 to cover the northern active mining area. It allowed geoscientists to successfully map previously unknown major faults and seam splits, which could potentially impact the mineability of the area. It is important to note, that faults interpreted using modern high-density 3D data can be interpreted with dramatically higher confidence in the fault dip and azimuth orientation in comparison to the legacy 2D data. Along with targeted drilling, pit mapping and structural interpretation, the outcome adds value to mine planning and operations. This paper outlines recent successful seismic 3D data acquisition and interpretation. In detail, the paper presents case studies on how the data can be incorporated into a structural model to improve geological knowledge, enable geotechnical assessment, and support safe and efficient coal mining in a large and structurally complex mine.

Mar 22, 2022

By J. D. Morgan

Introduction In 1986, the US economy passed the $4 trillion mark. However, the value of domestically processed materials of mineral origin fell slightly to $240 billion. The value of metals produced from US ores was unchanged at $5.6 billion, as was recycled scrap at $4 billion, while the value of industrial minerals rose slightly to $17.9 billion. Consumer demand strongly affects mining and the US economy is relatively saturated with longlived products. Moreover, in recent years there has been a steady increase in consumer, mortgage, and federal debt, inhibiting new purchases of goods. Motor vehicles and housing are major traditional markets for mineral materials. However, the 242 million US citizens already possess 170 million licensed motor vehicles and 92 million dwelling units. In 1986, domestic motor vehicle production fell 3%, to 11.3 million units, while new housing starts rose slightly to 1.8 million units. Nearly all mineral commodities move relatively freely in world trade. As detailed in Figs. 1 and 2, in the last three decades world production of major mineral materials has greatly increased. At present, substantial excess productive capacity exists not only in the US but also in many other countries. Consequently, the US mineral industry is encountering increasing competition from other sources, along with increasing competition from newer, engineered materials. For example, US production of plas¬tics has risen from 900 kt (1 million st) in 1950 to 22.7 Mt (25 million st) in 1986 - on a volume basis significantly greater than steel. Plastics, too, are mineral-based materials, some 7% of petrochemicals going to their manufacture. 1986 saw increased calls for protection. But President Reagan, in his 1987 State of the Union Message and Economic Report to the Congress, reaffirmed adherence to a policy of free and fair trade. However, he stressed the need for increased efforts to open foreign markets to US exports and to increase competitiveness of US industry US imports of mineral-based minerals in 1986 were valued at $40 billion and exports at $24 billion. Strategic minerals As detailed in Fig. 3, imports supplied a significant proportion of total US consumption of several important materials, including many classified as "strategic and critical." There were no changes in stockpile policy during the year. Congress debated the President's 1985 proposals to reduce stocks of World War II-type materials and to focus more on high technology materials needed for the cutting edge of future military material. But no final action resulted. However, Congressional concern about apartheid in South Africa did result in increasing pressure to limit imports of South African minerals. Meanwhile, the National Critical Materials Council in the Executive Office of the President intensified its efforts to be better able to advise the President. The Defense Production Act provides authority for priorities and allocations, supply expansions, voluntary agreements, and

Jan 5, 1987

By Harold L. Riley

This Bureau of Mines paper describes the methods and practices used at the Peck quarry of the Crab Orchard Stone Co., Inc., one of the leading producers of dimension stone in the Crossville, Tenn., area. The product is marketed under the registered trademark "Crab Orchard Stone". Another large producer of stone from the Crossville district sells its product under the registered trademark of "Tenn-Quartz". Both companies, and a number of other companies and individuals who quarry and process dimension stone from the same general geological formation, are members of the Quartzite Producers Association of Tennessee. The salable product is shipped throughout the country for use as architectural building stone. In 1959, 653,008 cubic feet of stone was produced in the Crossville area and was sold for $1,414,405. Terms and descriptions used in this report are those of the quarry and building trades. The offices, pitching sheds, wire saws, railroad siding, and storage areas of the Crab Orchard Stone Co., Inc., are on a side road 0.3 mile north from a point 2.2 miles east of Crossville, Tenn., on U.S. Highway 70. The quarry is on this same side road 2.0 miles south of Highway 70. Crossville is 62 miles west of Knoxville and 65 miles northeast of Chattanooga, Tenn.

Jan 1, 1962

By Jaime Tumialán de la Cruz

El presente texto busca describir las experiencias adquiridas en la mina de Cerro de Pasco a través del uso del "scooptram" eléctrico "LHD" de 2.2 yds. cú., marca "Jarvis Clark, a fin de mostrar su aplicación en otras minas cuyos problemas y características se asemejan a Cerro de Pasco. Los objetivos del empleo de este equipo son: aumentar la productividad en las áreas minadas por el método corte relleno descendente-mecanizado, mecanizar parte de la mina con equipos "LHD", pese a los problemas de ventilación, las temperaturas altas y reemplazar estos mismos equipos por aire acondicionado. En este sentido, se logró demostrar la eficacia del equipo eléctrico, especialmente en el uso de minas antiguas y de mayor profundidad, así como se mejoró las condiciones ambientales de trabajo y el costo de mantenimiento de los equipos eléctricos resultó más económico que las de diesels.

Nov 20, 1978

By Steve Kral

In the United States, the U.S. Environmental Protection Agency (EPA) is set to implement its Tier 2 air quality standards governing high-horsepower, off-road diesel engines. The regulations take effect in January2006. In Europe, similar standards, called Stages, are due to take effect about the same time. And other markets, such as Japan and Australia, have their own standards on tap. Tier 2 standards will further reduce the amount of nitrogen oxide (NOX), sulfur dioxide (SO2), diesel particulate matter (DPM), carbon monoxide (CO) and hydrocarbons off-highway diesel engines are allowed to emit. And even more restrictive Tier 4 standards are due in 2011. The upshot is that operators of high-horsepower engines, particularly in mining, will begin using in their new off-road haul trucks, excavators, shovels and other mining machines diesel engines that are designed to meet these more stringent standards.

Jan 1, 2004

By Jerry Pyatt

Lead has been used by mankind since before the Egyptian pyramids were built. Its durability provides for a continuum of innovation. As the largest integrated lead producer in the Western Hemisphere, The Doe Run Co. is committed to locating, mining, processing and sup-plying lead in ways that are responsible and sustainable. It takes ingenuity and resolve to successfully operate in the heavy industry field today. Doe Run is committed to applying responsibility through sustainability, lean manufacturing, safety, environmental stewardship, education and workforce development, and com-munity support.

Jan 1, 2008

The distribution or the userul minerals or Tasmania is so closely connected with the geological structure of the island that it will be convenient to briefly recapitulate the principal ract or its geological history, before describing the ore and other deposits. In many cases these present features which are very puzzling in the absence of knowledge of the structure of the districts in which they are found and in all cases it is of benefit to mining engineers to be acquainted with the main facts of the geological·history of the regions in which they have to carry on operations. Moreover, in speculating as to the origin of lodes and other deposits, we have constantly to rerer to the crumplings or the earth's crust by mountain-making movements, and to the igneous rocks which have been thrust throngh the other strata, to explain the origin or the lode fissures, and this discussion cannot be carried on without knowledge of local geology.The oldest rock yet met with in Tasmania are of Archooan age, and consist of highly crystalline quartzites and micaceous schist. They are most extensively developed towards the western side ot the island, forming a belt parallel to the West Coast from South-West Cape to Cradle fountain; but they also crop out here and there to the west and northward of this belt, where the covering strata or later age have been denuded away. Though not seen in situ in the eastern part of the colony, the abundance or pebbles derived from this formation in the conglomerates of the coal measures shows that it must in those day have formed land surfaces there also, and makes it likely that the archooan strata exist at no great depth: below many of the beds of later age now occupying the surface. Lying unconfortably upon these highly metamorphic strata we find next an extensive series of subcrystalline metamorphic conglomerates, grits, sandstones, slates, and limestones,of Cambro-Silurian age. These are well seen in the Gordou River Basin, along the West Coast Range, aloug the North Coast, and in the goldfields of the north-eastern portion of the colony. They are much broken by later intrusive rocks, and covered by younger rormations, but the series is spread more or less over the whole island.