Search Documents

By Ihor A. Kunasz

Lithium minerals occur predominantly in pegmatites that contain mineral assemblages derived from the crystallization of post- magmatic fluids or from the metasomatic action of residual peg- matitic fluids. They have been the traditional sources of raw material for ceramic and chemical industries. With the discovery of the Searles Lake deposits, brines became new sources of lithium, and, today, two brine deposits satisfy nearly one-half of the free world demand for lithium chemicals. Indeed, lithium production from pegmatites has been superseded by brines sources. In the United States, the brines of Clayton Valley, NV, have been exploited since 1964 by Cyprus Foote Mineral Company, a subsidiary of Cyprus Minerals Company. In Chile, Sociedad Chilena de Litio Ltda., an affiliate of Cyprus Minerals Company, is now producing lithium carbonate from the brines of the Salar de Atacama. Recently identified brine deposits suggest that these may well become the prime sources of lithium chemicals. In Bolivia, the government is negotiating the rights to exploit the brines of the Salar de Uyuni. The Salar del Hombre Muerto in Argentina is being evaluated as a future center of chemical production. The brines of the Great Salt Lake of Utah, the Smackover Formation, and the Imperial Valley geothermal field have been defined as important resources of lithium. In Tibet, high concentrations of lithium have been reported in several saline lakes. In the People's Republic of China, lithium may be produced from the brines of the Dabusan playa in the Qinghai Basin. The 1950s saw a great number of lithium companies develop. However, following the termination of the Atomic Energy Commission purchase program in 1959, several companies, such as Maywood Chemical Co., American Lithium Chemicals, and Quebec Lithium Corp., were forced to close their operations. Nevertheless, with the development of new applications in glass ceramics, air conditioning systems, synthetic rubber, and metallurgy (aluminumpotlines), the lithium industry grew steadily. With the potential application of lithium metal in batteries, nuclear reactors, and fuel cells, a steady growth can be foreseen. New products and new applications are likely to stimulate exploration for expanded reserves as well as the search for new sources from which lithium could be extracted economically. Presently identified reserves and production capacity are sufficient to satisfy the conventional market growth of lithium.

Jan 1, 1994

Most types of nuclear power reactors use uranium dioxide fuel. Power reactors using natural uranium dioxide fuel are of special interest to countries such as Australia that have their own uranium supplies. A wide range of uranium dioxide powders can be fabricated and the ideal one flows readily, presses without the need for binders or lubricants, sinters to the required density and gives low reject rates at all fabrication stages. Sinterable uranium dioxide is usually produced via the ammonium diuranate route.The Australian Atomic Energy Commission is aiming to demonstrate production of nuclear grade uranium dioxide from Australian concentrates, improving technology where possible. Details are given of the dissolution, solvent extraction, precipitation, filtration, drying, and· calcination-reduction steps. Solvent extraction from sulphate media is also under study with a view to developing a process to produce a nuclear grade product at the mine treatment plant site.

Jan 1, 1970

A study was made of zircon powders bonded with phosphoric acid or aluminium orthophosphate. The influence of strength of solution of the phosphatic binders on the modulus of rupture over a temperature range was investigated. Physical properties of three grades of zircon powder bonded with phosphatic binders were studied at various temperatures. Examination of x-ray diffraction data indicated that phosphates ofzirconia are preferentially formed to phosphates of silica. However, zircon in the presence of excess phosphoric acid also forms phosphates of silica upon heating.Resistance to attack by slags from blast and open hearth furnaces was determined on phosphate-bonded zircon mortars in a cup test with industrially made ladle bricks. Zircon powders bonded with phosphates proved to have high P.C.E. values. The first satisfactory results of a plant trial with phosphate-bonded zircon mortar, used in a steel ladle, are now being assessed in larger scale industrial tests prior to accepting the mortar as a steel plant refractory.

Jan 1, 1972

By Hazel J. Stratton

IN THE HALF-CENTURY that has passed since the Bureau of Mines was established in July 1910, the research and technologic investigations conducted by the Bureau's scientists, engineers, and other personnel have helped significantly in improving health and safety in the mineral industries and have contributed substantially in conserving the Nation's mineral resources through improved techniques in the mining, treatment, and use of mineral commodities. From Bureau laboratories have come new materials for industry and better methods of extracting and processing minerals and mineral fuels. Bureau safety investigations-complemented by equipment testing and by programs of mine inspection and education-have brought about safer and more healthful working conditions.

Jan 1, 1960

By John G. Peacey, Leoncio Sevilla G., Ford. Kevan J. R., Erling Villalobos C.

"Kinross Gold Corporation’s Mantos de Oro (MDO) gold/silver mine in northern Chile currently processes 15,000 tpd of oxide ores through a mill, whole ore cyanide leach plant followed by a Merrill-Crowe refinery. With the expected depletion of these oxide ores in a few years a new sulphide mineral deposit, Ladera-Farellón has been identified to potentially replace existing ore reserves. The deposit contains approximately 0.5g/t Au, 6g/t Ag and 0.5% Cu. The principal sulphide mineral in the deposit is enargite (Cu3AsS4) which hosts the majority of gold and silver and the copper. Direct cyanidation testwork has shown the sulphide mineral is refractory with a low gold recovery of 36% and silver recovery of 45%. Oxidation of the sulphides is required to liberate gold and silver and allow recovery of copper as an important pay-metal. Therefore, at MDO a new metallurgical process route with oxidation as a pretreatment step is required for viable treatment of such new sulphide mineralized material with acceptable recoveries of pay-metals.Analysis of flowsheet options was completed based on bench-scale and pilot scale metallurgical testwork as well as with reference to existing studies and operations. The process options investigated assume concentration of sulphides by flotation, followed by either pressure oxidation, bacteriological oxidation or roasting. Preliminary evaluation of flowsheet options focused on process risk, operability, technology availability and the economics of the project with emphasis on use of the existing metallurgical plant to reduce capital cost. Operating costs for each process option were also included in the relative analysis.The challenges of treatment of MDO sulphides, principally enargite and pyrite for recovery of gold, silver and copper center on fixation of arsenic and sulphur capture with environmentally acceptable disposal of residue tailings. This environmental focus was included in the process option selection and comparative analysis.This paper presents a review of the process options considered and highlights comparative advantages/disadvantages of each process with associated environmental issues. Preliminary conclusions are drawn on roasting as a potentially favorable process option for the treatment of MDO sulphides."

Jan 1, 2009

By J. E. Nesset

The bubble size, together with the gas rate, determines the bubble surface area flux in flotation machines and, therefore, impacts directly on the kinetics of flotation. Understanding the variables that influence bubble size is one of the keys to understanding flotation recovery. Surprisingly, these relationships are poorly understood, largely due to the difficulties associated with gas dispersion measurements in industrial environments. The McGill gas dispersion sensors (bubble size, gas rate, gas holdup) are capable of reliably making such measurements. This paper reports on a study, using the McGill sensors in a 0.8 m3 Metso RCSTM pilot cell, which investigated the effect on bubble size of frother type and concentration, gas rate, temperature and rotor speed. A Denver laboratory cell was used to investigate the effect of elevation above sea level. Frother concentration proved to have the predominant influence on bubble size, and the effect of frother type can be normalised as a function of the critical coalescence concentration (CCC). Measurements made at many plant sites worldwide are compared to the model developed using the Metso RCSTM unit.

Jan 1, 2007

By Carlos Neira R

Dentro de la minería, el sistema de control tipográfico es importante puesto que guía las labores de exploración a través de las mediciones del terreno y el cálculo de coordenadas. En ese sentido, el presente texto señala una nueva forma de aplicación mediante el uso de un microcomputador y los programas de cómputo, de forma que este apoya los cálculos y graficación de poligonación, así como los cálculos de triangulación compensada por vértices y figura, los de cuadriláteros ajustados por mínimos cuadrados, los de coordenadas y el cálculo de movimiento de tierras.

Aug 26, 1988

Close spatial relationships between the deposits of the Etheridge Goldfield (23 000 kg of bullion) and various regional geological and geophysical features suggest that genesis of the ore deposits was a multi-stage process that started with magmatic and metamorphic stages in the mid-Proterozoic, climaxed with structural and hydrothermal stages in the late Palaeozoic and terminated with an oxidation enrichment stage in the Cainozoic.This hypothesis permits classification of the Georgetown region into areas likely to contain deposits of the Etheridge type and those unlikely to do so; it is concluded that there is little scope for the discovery of extensions of this field.However, the stratigraphic interval between the postulated source rocks of the Etheridge field and stratigraphically higher host rocks of the Croydon field may contain disseminated replacement gold deposits of the Carlin type. The potential host (Pyritic carbonaceous, and locally dolomitic siltstone of the Candlow Formation) is locally faulted and cut by granitoids and the extension of a mineralised, long-standing zone of structural weakness.

Jan 1, 1981

By Shimi Tzobery, Jay Davenport, Raymond Henn, Sam Bandimere

Over the past several decades, the use of cement-based grouts using ultra fine cement as a replacement for portland cement has begun to gain acceptance as an alternative to chemical solution grouts used in permeation grouting. The amount of information currently available on grouts made with ultrafine cement is limited. The authors used a previously developed field testing program to perform additional tests to evaluate the permeation performance of portland and ultrafine cement-based grouts. For the first time, the 2003 testing program included an attempt to determine the 28 day compressive strength of the sand permeated by the grout.

Jan 1, 2005

OneSteel and BlueScope Steel have been working with the CSIRO to develop sustainable carbon fuels and reductants which are suitable for use in the iron and steel industry. One of the initial focuses of this work has been a process called steel recarburisation which is the addition of carbon to liquid steel to produce particular steel grades. This paper reports on the preliminary work and the recent full scale recarburisation plant trials conducted at the OneSteel Sydney Steel Mill.   Preliminary experimental work involved kilogram scale recarburisation of liquid steel with a range of commercial and prepared charcoal products. This work showed that charcoal dissolves into liquid steel very quickly and that carbon recovery to steel was inversely related to the charcoal volatile content. Initial larger scale work focused on the collection of wood, and preparation of low volatile charcoal which is required for steel recarburisation. Approximately three tonnes of charcoal was prepared at the Corrimal coke ovens of the Illawarra Coke Company. This charcoal was dried, crushed, sized and packaged in a form suitable for addition to 80 tonne liquid steel ladles.   The recarburisation trial was conducted over 30 ladle heats during June 2009. The charcoal was manually added to the liquid steel in 5 kg bags using normal plant practice. Conventional commercial recarburiser was also added to the liquid steel in alternate ladle heats. The performance of the charcoal was compared with the conventional recarburiser based on the carbon recovery to steel, hydrogen pick-up by steel and the rate of carbon dissolution into steel.   An analysis of the trial results showed that the charcoal performed at least as well as commercial recarburiser in carbon recovery and rate of dissolution but may have resulted in a slightly higher hydrogen content of steel. This is probably due to the higher moisture content of charcoal. The main challenges in the future include: increasing the charcoal density to improve transport and handling economics, securing a sustainable supply of biomass for the steel industry and developing a charcoal production industry so materials of suitable quality for both production and trials on other applications can be conducted.

Jun 1, 2010

Beneficiation Studies of Dolomitic Rock Phosphate in Pursuit of Zero Waste Technology - A Case Study

Sep 13, 2010

By D. Tsweleng

In the Evraz Highveld production process, iron ore is prereduced in rotary kilns prior to charging into submerged arc furnaces (SAFs). Owing to the highly aggressive slags that are formed within the combustion zones of these kilns, chrome-oxide-containing lowcement castables have been used for some years in the kiln lining. Due to concerns around the potentially harmful effects should Cr(V1) be present in the spent linings, Highveld and its suppliers of kiln castables devoted time to developing alternative chrome-free lining materials. Such materials needed to be cost-effective and ensure good performance and improved kiln availability. This paper discusses all the parameters surrounding this development. Keywords Low-cement castable, chrome-oxide free, chrome (VI), titaniferous magnetite ore, rotary kiln, submerged arc furnace, open slag bath furnace, Evraz Highveld Steel & Vanadium Limited.

Aug 1, 2013

By K. K. Murray, D. G. Gelderland

"The pressure oxidation autoclave at the Goldcorp’s Red Lake Gold Mines (RLGM) was commissioned in 1991. Since commissioning, the circuit has been well maintained and its capacity increased to mechanical and gaseous oxygen limitations. With advances in available technology, opportunities to produce more sulphide concentrate and a changing business environment, an optimization project has been initiated at RLGM. A multi-phase approach has been developed to optimize both the operations and economics of the circuit. This paper describes the history and future of the autoclave circuit at RLGM.AcknowledmentsWe would like to thank the operations and maintenance staff at Red Lake Gold Mines for their support and openness of mind to enact changes to enhance the operation. We would also like to acknowledge the members of the integrated team from Red Lake maintence, metallurgy, operations and corporate technical services that did the hard work to push past the status quo in order to advance productivity.OpportunityThe Red Lake Gold Mines (RLGM) pressure oxidation (POx) circuit has been in operation for over 25 years processing the high sulphide content gold bearing minerals. Increased sulphide concentrate production from improved flotation recovery and increasing gold sulphide association at depth has led to the POx circuit becoming a throughput bottleneck. The opportunity exists to process increased tonnages of sulphide concentrates and increase gold production. In order to realize this value, it will be necessary to increase the throughput capacity of the POx circuit.BackgroundThe POx autoclave at the RLGM, commissioned in 1991, was Canada’s first gold autoclave. It was installed to replace the two-stage fluid bed roaster that was built when the Campbell mine and mill were constructed in the late Forties. The circuit was originally designed to process 12.5 t/d sulphide sulphur in about 50 t/d of Campbell flotation concentrate. Following the merger of the Campbell and Red Lake Mines in 2006, the POx circuit started processing flotation concentrate from both Campbell and Red Lake Mills. In recent years, the circuit has been processing about 18 t/d sulphide sulphur in 75-85 t/d flotation concentrate."

Jan 1, 2017

By S. C. Sun

Pennsylvania has ample reserves of high-alumina clays which are potential sources of alumina, but many of these clays contain large amounts of iron, which makes them unsuitable for treatment by acid processes(1). The purpose of this investigation was to determine the optimum conditions for the selective hydrochloric acid leaching of iron (2-4) prior to the sulfuric acid extraction of alumina from Pennsylvania ferruginous high-alumina clays. This was accomplished by first testing the iron-bearing minerals and the clay minerals most often encountered in Pennsylvania clays to determine their rate of dissolution in hydrochloric acid solutions. The results of individual minerals were then based for leaching Pennsylvania clays with a 19% hydrochloric acid solution at the boiling point of the acid for approximately 30 minutes to achieve as high as 90% iron removal and only 2-5% alumina losses.

Jan 1, 1968

By Mats Keisu, Bengt Niklasson

The Sofia project has increased the level of knowledge and technique within tunnelling, drifting and contour blasting.

Jan 1, 1992

By Jim Richards, Eli Choueiry, Brett Robinson, Amanda Elioff

The Los Angeles Metro Gold Line Eastside Extension (MGLEE) extends Metro’s light rail system to the densely populated and growing East Los Angeles communities. Much of the 6 mile alignment consists of at-grade track, but the project also features a1.7 mile underground segment in cut-and-cover and twin-bored tunnel structures. In light of past experiences with open shield construction, The Metropolitan Transportation Authority (Metro) specified, for the first time, use of Pressure Face Tunnel Boring Machines (TBM’s) to advance tunnels through soft ground. This paper describes the history of the tunnel design, construction management, and construction methods adopted that resulted in successfully completing the tunneling segment.

Jan 1, 2007

THE Synthetic Liquid Fuels Act (30 U.S.C., 321-325, and amendments) become law April 5, 1644, and a period of intensive research and development in this field was begun by the Bureau of Mines. As part of this program bulletins were published on a pressure hydrogenation,3 the Fischer-Tropsch synthesis,4 and oil shale.5 The Bureau also has published a short bibliography on coal gasification,6 mostly of a theoretical nature. Because coal gasification is prerequisite to Hither the Fischer-Tropsch or coal-hydrogenation processes, publishing this sizable, collection of technical information in this form will be valuable. The material is presented in three parts, as follows: I. United States Patents. II. United Kingdom, Australian, Canadian, and South African Patents. III. Belgium, French, German, Italian, and Swedish Patents. The domestic patents for this bulletin were collected between 1963 and 1955. Some of the Foreign Patents were collected at the same time and a few of them later in 1961. Part I was published in 1960; Part II was published in 1962.

Jan 1, 1964

By Fernando Ruiz Díaz

En aplicaciones a elevadas temperaturas como por ejemplo en cámaras de combustión y toberas de vehículos aeroespaciales se requiere el uso de aleaciones que permitan una elevada extracción de calor y buenas propiedades mecánicas. En este trabajo se realiza un análisis comparativo de las aleaciones Cu-Cr-Zr y Cu-Ag-Zr. Las mismas fueron sometidas a ensayos de resistividad eléctrica entre 25ºC y 700ºC y de tracción a 150ºC, 450ºC y 700ºC. Los resultados de los ensayos de resistividad eléctrica fueron convertidos a conductividad térmica mediante la relación de Wiedemann- Franz. A través de este análisis se observa que la aleación con mejor conductividad térmica es la de Cu-Ag-Zr presentando además un cambio de fase que no es observado en la aleación Cu-Cr-Zr. Respecto al ensayo de tracción la aleación Cu-Cr-Zr presenta mayores valores de resistencia a la tracción y tensión de fluencia a las temperaturas estudiadas.

Aug 16, 2017

By John Chadwick

In the drive for faster development advance rates, railbound systems can be advantageous, in the right application. Skanska BS, the contractor to mine-owner VSK Mining, is driving an adit access deep into the Volouské Urchy Mountain in Slovakia to access the Gemerská Poloma talc deposit, some 70 km (43 miles) west of Ko?ice, the economic and cultural center of eastern Slovakia. Skanska began driving the Stolna Elisabeth drift in February 2007, extending 25 kg/m (50 lb/yd) rails (with 750 mm or 30 in. between sleepers) into the mountain to provide the main haulage to bring talc ore and waste out of the new mine once it gets into production. It will also be used for personnel transport, and is now almost complete. As a second egress and for ventilation, a 2.5-m- (8.2-ft-) diameter shaft of about 300-m (984-ft) depth will be sunk from surface down into the orebody. Stolna Elisabeth is a 4.2-km- (2.6-mile-) long drift mined at a cross section of some 11 m2 (118 sq ft). The finished profile is 3.2-m- (10.5-ft-) wide by 3.6-m- (11.8-ft-) high. It has been developed on a very slight incline so that water runs down it to the portal. The portal is 450 m (1,476 ft) above sea level and the end of the tunnel is 475 m (1,558 ft) above sea level. Much of the rock through which it has been developed is magnesite with a compressive strength of 150 MPA. The drilling jumbo is an Atlas Copco twin-boom Boomer 282 Raildrill drilling 42- to 45-mm- (1.6- to 1.7-in.-) diameter holes to a maximum length of 2.5 m (8.2 ft), depending on ground conditions. This is a drill jumbo that Skanska has used successfully on a number of projects during its life. The condition of the rock through which this drift has been driven is extremely variable. Five classifications of A1 and A2 and B1, B2 and [ ] B3, where A1 is the most competent rock and B3 is the worst, have been established. The amount of support used, of which more later is determined by the classification of ground conditions. At the time of the author?s visit, the project it was about 40 days ahead of schedule, thanks to high advance rates. For instance 6 m/day (20 ft/d) was the plan for the advance to be achieved in B1 rock, but sometimes the crews have achieved 8 m/day (26 ft/d) ? which is the average for the whole project ? in those conditions. In A1 the best advance rate achieved is 12 m/day (39 ft/d). The loading unit is a Häggloader 9HR-B on crawler tracks with a pony track to run on the rails. This allows the unit to be towed up and down the drift along the rails. To load from the face, the Häggloader lowers the foot of its onboard conveyor system to the floor and the backhoe pushes material on to it. This digging arm-conveyor combination produces uninterrupted, optimal volume loading of the haulage unit, without spill ? a technique offering load capacities as high as 180 m3/h (6,356 cu ft/hour). Further-more, as an electrically powered machine, it offers great

Jan 1, 2009

By Juan M. Antorena

A pile driving and testing program was undertaken to evaluate installation procedures, assess capacity, particularly in uplift, of 360- and 460-mm (14- and 18-inch) square prestressed concrete piles and provide foundation design parameters for the New Mid-Point Bridge project in Fort Myers, Florida. Nine piles were dynamically monitored during installation, and six piles were monitored during restrike driving to evaluate pile drivability and uplift and bearing capacity including time related capacity increases due to soil "set-up". In addition, two static load tests (tension and compression) were performed to calibrated the results obtain during the dynamic testing. This paper presents descriptions of the pile driving testing program along with findings regarding pile uplift and compression capacities from the static load testing, pile capacities from dynamic testing (CAPWAP® analyses), soil-pile adhesion values, wave equation factors, soil strength vs. time dependency, foundation design (anticipated pile tip elevation) and pile driving recommendations.

Jan 1, 1995