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By Dong G. Chae

A model for the leaching of oxide ores is developed and II correlated with laboratory tests for percolation leaching of copper oxide are. Using the model, recovery of metal values and lixiviant concentration of the effluent solution at any time may be evaluated. For the copper oxide ore a simplified version of the model is examined for the leaching mechanism consisting of: 1) a surface flush reaction with the highest rate of lixiviant consumption; 2) penetration of lixiviant to react with copper minerals and gangue constituents; and, 3) slow lixiviant consumption, mostly by residual gangue materials. The simplified model is able to explain reasonably the leaching behavior of copper oxide ore by introducing a concept of effective initial size to correct for packing in a bed of fine particles.

Jan 1, 1979

Surface subsidence that results from longwall mining can be large magnitude and can affect significant areas. Conventional methods for subsidence monitoring include leveling, global positioning system (GPS), and photogrammetric surveys. Remote sensing techniques, including aerial LiDAR, terrestrial laser scanning, and satellite-based differential interferometric synthetic aperture radar (DInSAR), are also used to measure deformation associated with subsidence. DInSAR data are different than data from conventional subsidence surveys. Images capture data over large areas (hundreds of kilometers), and each pixel (data point) in an image quantifies the average displacement over an area of square meters. DInSAR data can have fairly high time resolution; imaging periods typically range from weeks to months.

Jan 7, 2020

By H. H. Schrenk

The purpose of respiratory protective equipment is to prevent the inhalation of harmful or objectionable atmospheres. Although constituents or contaminants that may render an atmosphere irrespirable or objectionable are numerous, they may be classified broadly as follows: I. Gaseous substance: n. A. Toxic. B. Inert (oxygen deficiency). II. Particulate matter (dispersoids). A. Solid. a. Dust (formed by disintegration). b. Pure (formed by condensation). B. Liquid. a. Mist (formed by disintegration). b. Fog (former by condensation).

Jan 1, 1940

By Dr. G. R. Hoey

"Abrasive wear and corrosive wear of carbon-steel grinding balls occurred simultaneously during the wet-grinding of hematite iron ore, and Ni-Cu sulphide ore, in laboratory ball mills. Two corrosion control methods, the use of corrosion inhibitors and pH control, were investigated and found to be effective means of reducing or preventing corrosive wear. Up to 50 % reduction of total ball wear resulted from the use of these methods.Corrosive wear is caused principally by the reaction of oxygen in air with the carbon-steel grinding balls, probably by the following reaction: 2Fe + O2 + 2H20 - 2Fe2 + 40H-.IntroductionA survey of corrosion problems in Canadian sulphide ore mines was completed and the findings were published in 197l(l). The corrosion survey was used to develop the present research program with the objective to find more economical and effective ways and means to reduce the corrosion that occurs in the mining and metallurgical industry. The purpose of this presentation is to review the projects being done by staff members of the Corrosion Section, Extraction Metallurgy Division, on corrosive wear and its control in wet-grind ball mills.Both abrasion and corrosion contribute to metal consumption during wet grinding of ores. The total wear of grinding media in this study is assumed to be equal to the sum of corrosive wear and abrasive wear. A great deal of research and development has been reported in the literature on ways to improve the abrasion resistance of grinding media but only a small number of studies has been reported on the corrosion resistance of conventional grinding media."

Jan 1, 1974

By J. Luxford

The last decade has seen an enormous increase in the use of contractors right across the Australian mining industry. So much so that contractors now operate 33 of the 68 underground metalliferous mines around Australia and are making significant inroads into iron ore in the west and coal in the east. Safety used to be a low priority for many contractors. The picture has changed dramatically in recent years as most contractors take a far more professional approach to safety management. This paper examines the changes that have occurred and the requirements for effectively managing safety in a contracting environment.

Jan 1, 2000

By Virgil A. Marple

The primary purpose of this contract was to evaluate methods and techniques by which the size distribution acid concentration of mining-related dusts can be measured. One result has been the development of a portable, battery-operated optical particle counter/ multi-channel analyzer system which can he used to determine the size distribution and concentration of mining aerosols. One important aspect of this program has been the development of a calibration technique which relates the output of the optical particle counter to the penetration of the particles through an impactor: This results in a calibration curve in terms of the aerodynamic or Stokes' diameter or the aerosol particles. Using this technique, calibrations were performed on coal, silica, Arizona road dust, potash, and rock dust (corer ore) aerosols. Another task of this program was the calibration and evaluation of the GCA respirible dust monitors (RMD) 101-1 and 301. The results of evaluation showed that the instruments were within the manufacturer's specification of ±25% of the true mass concentration up to about 15 mg/m , if the dust particles were in a size range from about 0.7 to 10 µm aerodynamic diameter. Particles smaller tan about 0.7 µm were not collected by the instrument and particles larger than about 10 µm were lose in the inlet. Other tasks included performing field studies in cooperative research programs with the Bureau of Mines personnel, development of a portable polystyrene latex generator for use in optical particle counter calibrations in the field. The incorporation of impactor classification devices on the inlets of aerosol mass measuring instruments to give mass size distributions, and a study of the density of coal particles as a function of the particle size.

Jan 1, 1977

By Tomás Chaparro Díaz

El presente trabajo presenta una metodología para evaluar al supervisor de seguridad -en tanto considera el conocimiento y las habilidades personales del mismo. Para ello, se revisa tres maneras de evaluar los factores de eficiencia del supervisor como: conocimento, aceptación y pasión. Dichos factores fueron aplicados exitosamente en la operación I Cerro Corona, (Cajamarca) mediante la fórmula E=QxAxP, basada en la metodología Six Sigma en la operación. De forma que se convierte en una guía para el proceso de selección y genera un marco referencial en la evaluación de las competencias claves del supervisor de seguridad.

Oct 1, 2013

By A. D. Davis, J. L. Sorensen, C. J. Webb

Environmental impacts from acidic mine drainage are growing national concerns that are particularly acute in the headwaters of the Rocky Mountain region. In the Black Hills of South Dakota, approximately one thousand mines are inactive or abandoned, most of them in the headwaters of major drainages. This paper examines the Bear Butte Creek basin, a heavily mineralized watershed with significant historical mining impacts and a surface gold mine permitted in 1997. The watershed loses its surface discharge to swallow holes in the karstic Madison Limestone. The integrity of the aquatic ecosystem was monitored with a suite of sitespecific bio-indicators. Stream surveys covered the entire reach of Bear Butte Creek from near its headwaters to the swallow holes in the Madison aquifer. Data from the stream surveys, water-quality sampling, and bio-indicator surveys clearly showed that water-quality impacts are limited mainly to Strawberry Creek and to the area of Bear Butte Creek near and downstream of the town of Galena.

Jan 1, 1999

By Paul Grady, Martin Froehling, Curtis Mohns, Eliab Roman

"Since the idea of processing rock to unlock the valuable minerals inside was put into practice, efforts to improve production began. Methods have been learned that allow for operation in environments and under circumstances where it would not have been possible until now. All existing operations have experienced at least some form of productivity improvement measures. The objective is simple: generate more product of better quality in less time and at lower unit cost. Since the year 2000, various modifications have been made at the Kemess Concentrator in efforts to improve productivity. The following is a discussion of these modifications and their contributions to the success of the operation.INTRODUCTIONThe Kemess South Mine, a major producer of gold and copper, is located in north-central British Columbia. Kemess was brought into production in May 1998 by Royal Oak Mines with a modern mill controlled by a fully integrated Foxboro IA DCS system and employing 134 people. On February 11, 2000 Northgate Exploration Limited (now Northgate Minerals Corporation) acquired Kemess Mine from receivership. Since acquisition in 2000, Kemess has seen many accomplishments, including the reduction of costs by 40% site wide.The mill has a nameplate capacity of approximately 56,000 tonnes per day which is processed through a Metso (Svedala) 60” x 89” Primary Gyratory Crusher and then conveyed by a 60” conveyor to a stockpile with 48 hours of total storage capacity. The nominal minus 6” rock from the stockpile is fed to two parallel grinding circuits (A & B). Each section consists of a 10.4 m F x 4.7 m SAG mill with dual drive motors (4,480 kW apiece) discharging onto a 2.4 m x 7.3 m Metso (Svedala) single deck vibrating screen to remove the coarse material for recycle to the SAG mill by a Continental 45º high angle sandwich conveyor. Screen undersize is pumped along with ball mill discharge to a cyclopac consisting of twelve Krebs 66 cm F cyclones to classify flotation feed to a size of approximately 65% minus 200 mesh. Cyclone underflow feeds a Metso (Svedala) 6.8 m F x 11.0 m ball mill, also with dual drive motors (4,480 kW apiece). The primary grinding circuit has 35,840 kW available for grinding."

Jan 1, 2005

By Ed Billington, Mike Shields

The trail blaster is faced with a wide range of workrelated challenges, not the least being the work setting itself. It is usually remote, being anywhere from 5 to 30 or more miles (8 to 50 km) from any road. It may be in mountains, high rock desert, or coastal rain forest, and can range from sea level to over 12,000 feet (3700 m) in elevation. The blaster may be part of a 2-person clearing crew, a 4-person maintenance crew, or a 10-person construction crew. The crew will usually be mobile, moving and working up to 10 miles (16 km) or more per day, relying mostly on their own backpacks to move camp, tools and supplies from site to site. Periodic resupply may be by helicopter, aird rop, or even “sherpa” groups, but most often will be by packstrings of horses and mules. The crew goes into the backcountry a n y w h e re from two weeks to three months at a time, and while there, its members “live the job” 24 hours a day, enjoying baking heat, torrential rain or mid-July s n o w s t o rms along with the truly glorious weather that c o m p e n s a t e s . So who is this blaster? Well, “he” may be she, since some of the top trail blasters are women. He/she will also be more than a blaster: Crews are small, so experienced members must be capable of handling the full range of trail work. Thus this blaster is also a driller, and usually also a bucker, snag faller, rigger, dry-stone mason, log and timber carpenter, bridge builder, mule p a c k e r, small-engine mechanic and, not least, camp cook capable of putting out a hot meal from a campfire , in a downpour, in the dark. Being in remote locations, often without reliable communication to the outside world, trail crews enjoy a remarkable degree of independence from “supervision.” With that comes the responsibility to make sound decisions which expedite the work, while promoting crew safety and welfare .

Jan 1, 2004

By Paul C. Schmall, John F. Donohoe, Arthur B. Corwin, Derek Maishman

Ground freezing was utilized to provide complete stability of the excavation face and complete groundwater cut-off for the jacking of the three tunnel boxes for the Interstate 90 / Interstate 93 approach to the Fort Point Channel crossing. Through a wide range of geological conditions and large buried obstructions, the freezing provided complete stability of the face so that a 11.5 m (38 ft) high free standing vertical face could be mined without the need for any additional face support. Obstructions were incorporated into the massive frozen ground matrix, and held in place so that they could be excavated with a minimum of disturbance. The freezing provided an absolute groundwater cut-off, and permitted the work to be done without disturbance to the active rail system immediately above. With the use of instrumentation such as borehole thermocouples, the effectiveness of the freezing was guaranteed and the jacking proceeded with complete confidence and assurance of the ground conditions ahead.

Jan 1, 2001

By Walter D. Holland

This study was undertaken to determine miners' breathing zone concentrations of diesel exhaust components, to investigate any relationships between these concentrations and vehicle type, the presence of emission controls, vehicle usage, and ventilation conditions, and to make recommendations for monitoring and ventilation requirements. Twenty-four mines including two con l mines were surveyed. Sampling was done for CON, NON, SOx, PNA, aldehydes, and particulates. hi most mines, concentrations of at least one contaminant exceeded one half the standard or TLV. The concentrations of gases arc probably sufficiently reduced by a minimum air velocity of 50 fpm. A sufficient reduction of particulate concentrations may require as high as 400 fpm air velocity. Vehicle age, type, or usage appear to have little or no effect on contaminant concentrations. PNA levels were below detection limits in all but a very few samples. Minimum requirements for routine monitoring should include formaldehyde, COx, NO2. It is further recommended that better definition of the minimum ventilation requirement be obtained.

Jan 1, 1978

By Ernest M. Spokes

For bituminous and lignite coals the economic picture continued to improve as it has each year since the low of 1961, with production at 480 mil- lion tons in 1964 compared with 1963's 459 million tons. The anthracite industry produced 16.3 million tons in 1964 and 18.3 million tons in 1963. The industry is looking toward a further expansion; among the new developments will be a mining wheel producing 3 million tons of lignite per year in South Dakota. It is expected that electric power generation will continue to provide the market for most of the increase in consumption, with exports second in importance in the expansion. Improvements in methods of mining and transporting coal underground and in strip mines, and the cooperation of carriers in finding ways to reduce transportation costs to distant markets, have made possible these expansions. Research continues to reduce costs of mining, transportation, steam generation of electric power and production of steam for space heating and manufacturing processes, to retain some markets and expand others. Other research seeks to expand markets by developing fuel from coal which will be more attractive than competing fuels, by reducing sulfur and other sources of air pollution. Public relations efforts of the industry are bearing fruit in a greater acceptance of coal as a modern fuel.

Jan 2, 1965

By J. Davis, M. G. Reading

"INTRODUCTIONInternational Minerals and Chemical Corporation (Canada) Limited operates two potash mine/refinery complexes near Esterhazy, Saskatchewan. Annual production of approximately 4.2 million tons is sold in the United States and overseas in five grades according to size and quality.Ore grading 25% K2 0 equivalent is mined from a horizontal bed by continuous boring machines, crushed, and hoisted at 8 inches. The refinery operation consists of the eight basic steps shown in Figure 1. Particle sizes handled are similar to those experienced in other forms of mineral beneficiation: 8 inches to 100 mesh. The ore is crystalline and particles are angular. Fortunately the major mineral constituents, sylvite (KCl) and halite (NaCl), demonstrate relatively low hardness at 2 to 2.5.Therefore, while simple abrasion must be acknowledged, it is not a major problem except, of course, in circuits carrying magnetite.Corrosion, as represented by the classic equations of Figure 2, occurs in all its various forms."

Jan 1, 1983

By John Lindsay

"Although diamond mining is a relative newcomer to the Canadian mining industry, with the first diamond mine coming on stream in 1998, Canada is already a significant producer of high quality diamonds. This paper will review diamond production trends and highlight some of the projects currently under development, which have the potential to enhance Canada’s role as a significant diamond producer.Diamond recovery plants generally incorporate well-established mineral processing and recovery techniques, with issues such as product security, cut-off sizes, and diamond preservation becoming important considerations when developing process flowsheets. A diamond processing plant must achieve three key objectives, namely:• Liberation of the diamonds from the host rock;• Separation of the heavy minerals, which include the diamonds, from the host rock;• Recovery of the diamonds from the heavy mineral concentrates.Processing technologies and equipment commonly utilized in diamond processing plants will be reviewed and some of the significant issues associated with each option briefly discussed.Typical process flowsheets will be presented.Finally, an overview of De Beers’ Victor diamond project, located in northern Ontario, will be provided. This potentially significant diamond producer is currently at a pre-feasibility stage of development.DIAMONDS IN CANADAWorld Diamond ProductionCommercial diamond mining commenced in earnest with the discovery of the Kimberley diamondfields in South Africa in the late 1800s, and this resulted in a dramatic increase in the supply of diamonds. As can be seen from figure 1, world diamond production, mainly from South Africa, Angola, Congo, and Namibia, remained relatively constant through the early 1900s until the development of the large Russian kimberlite pipes in the 1950s. Production increased again in the 1960s and 70s with the development of the Botswana mines, but the most significant increase in global production came from the Argyle mine in Australia, which came on stream in 1983 and produced a peak of almost 43 million carats in 1994, representing approximately 40% of the world market. Production from Argyle has since fallen-off as grades have declined and the strip ratio has increased with the deepening of the open pit."

Jan 1, 2003

By Fulvio Tonon

And Rabcewicz said ?tunnels should be driven full face whenever possible.? ADECO, which stands for ?Analysis of Controlled Deformations in tunnels,? now allows us to fulfll Rabcewicz?s dream in any stress-strain condition. In order to achieve that dream and its consequent control over cost and schedule, however, NATM must be abandoned for the ADECO. The paper presents the basic concepts in the ADECO approach to design, construction and monitoring of tunnels together with some case histories, including: full face excavation for Cassia tunnel (width of 22 m, height of 14 m) in sands and silts under 5 m cover below an archeological area in Rome, Italy; Tartaguille tunnel (face area > 100 m2) advanced full face in highly swelling and squeezing ground under 100 m cover where NATM led to catastrophic failure, France; and 80 km of tunnels (face area > 100 m2) advanced full face in highly squeezing/swelling ground under 500 m cover for the high-speed railway line between Bologne and Florence, Italy (turnkey contract).

By Edwin Anatolio Calderón Vicuña

En la actividad minera, los costos de operación en perforación y voladura son importantes puesto que el logro óptimo de una voladura óptima, no debe afectar la eficiencia física y económica de las demás operaciones (perforación, carguío, transporte, trituración). En este sentido, el presente texto nuevos diseños de perforación y voladura en las vetas angostas donde se elimine la sobreexcavación y el costo de sostenimiento.

Nov 24, 1993

By Philip Bonanno

The first major project in Boston's new access to Logan Airport was an Immersed Tube Tunnel which extended 3,600 ft. from South Boston to East Boston across Boston Harbor. Twelve tube sections, 300 ft. long x 80 ft. wide x 40 ft. high, were lowered into an excavated trench which was then backfilled. The depth of the trench at mid-channel was approximately 100 ft. below mean high tide. At the East Boston end the tube terminated close to the present shoreline. At the South Boston end the tube terminated approximately 600 ft. inland from the shore line where a ventilation building was required. The depth to subgrade from existing ground at the ventilation structure was approximately 85 ft. The soil profile at this location consisted of 50 ft. of miscellaneous rubble fill, 25 ft. of Boston blue clay, and 10 ft. of glacial till. A small amount of weathered argellite existed at the north end of the structure. Part of the Morrison Knudsen, Interbeton, J.F. White, Joint Venture contract to construct the Immersed Tube Tunnel (ITT) was the construction of a cofferdam at the tube/ventilation building interface. The ventilation building was to be built as part of another contract. The construction of the cofferdam and the excavation to the building subgrade was the responsibility of J.F. White Contracting Company.

Jan 1, 1994

Spectrum Resources commenced operations as a public listed mining company in August, 1983, with a variety of precious metal projects in New Zealand. At that time the outlook for most mineral commodities, with the notable exception of precious metals, was decidedly gloomy. Metal prices were depressed and demand forecasts were universally gloomy. Against this background the company reviewed the non-traditional metals sector to try and identify a 'new' metal with an above average demand growth and market value. Lithium, a commodity with exciting new applications in storage batteries and alloys, met both criteria. Annual world consumption of lithium is around 7000 tonnes; current prices are around $NZ40/lb for lithium metal and demand growth is projected at five to seven per cent per annum. Geothermal fluids at Wairakei and elsewhere contain anomalous amounts of lithium and in May, 1984, the Chemistry Division of DSIR was commissioned to carry out a literature survey on the possible recovery of lithium and other minerals from geothermal waters. The survey results were encouraging and the company subsequently negotiated exclusive access rights, for research purposes, to geothermal discharge fluids from the Wairakei and Kawerau geothermal fluids. Most of the subsequent investigations reported here were carried out by Chemistry Division, DSIR, under contract to the company with some assistance from the Industrial Processing Division, DSIR.

Jan 1, 1986

By Pengfu Tan

A thermodynamic model has been developed to predict the distribution behaviors of Cu, Fe, S, O, Pb, Zn, As, and heat balance in a lead blast furnace. The modeling results have been validated by the plant data of a lead smelter in Asia. The model can be used to predict for any set of controllable process parameters such as feed composition, smelting temperature, degree of oxygen enrichment and volume of oxygen-enriched air. The effects of the blast air, industrial oxygen, and coke charge on the distributions of Cu, Fe, S, O, Pb, Zn, As, and heat balance, and on the lead loss in slag have been presented and discussed.

Jan 1, 2005