Search Documents

By P. C. Miller

The paper reports laboratory results from the bioleaching of chalcopyrite ores and concentrates using a mixed moderate thermophile culture. Copper dissolution in excess of 95% was achieved in all cases with the majority of tests indicating copper dissolution in excess of 98%. Aspects of downstream processing are discussed in relation to iron rejection by precipitation. The laboratory results indicate the need for careful control of the pH value to prevent co-precipitation of the copper with iron. A comparison of capital and operating costs is given indicating potential differences between the use of toll smelting and bacterial leaching on site. A discussion is given highlighting the sensitive cost areas of these two process routes.

Jan 1, 1997

The Cadia Mine is located 25kms South West of Orange in the central west of New South Wales (NSW), Australia (Figure 1). Orange is a major regional centre with a population of 35,000 people. Cadia has a history of mining and exploration dating back to 1851 and shortly after the first Australian gold rush at Ophir, north of Orange. Newcrest Mining commenced an exploration program at Cadia Hill in 1992. This identified a substantial zone of copper and gold mineralization. Subsequent resource definition drilling defined an orebody with a mineable reserve of 200 million tonnes of ore with an average gold grade of 0.74g/t and 0.17\ copper. A full feasibility study commenced in 1994, approvals to proceed with development were granted in September 1996 and the processing plant was commissioned in July 1998. The project came in on budget at A$440 million and on time, 24 months from design to construction. The estimated operating cost at the time of commissioning was A$8.85/t of mill feed.

Jan 1, 1999

By James G. McKelvey

Owners have seen several major tunnel projects in recent years fall victim to a general reduction in the number of bidders as well as an erratic range of pricing. It should be noted though that this is not a universal trend and some projects have seen good competitive bids. Contractual terms and conditions are an important factor in attracting good competition. The Front End documents of tunnel projects have come under increasing scrutiny as tunneling contractors in the U.S. industry are looking much more closely at their risk exposure in the contract terms and conditions. Considering the amount of tunnel construction work upcoming in North America, it is important that General and Special Conditions are put together in a way that provides a reasonable basis to execute the Contract and also provide a fair, balanced and swift way to resolve disputes.

Jan 1, 2008

By H. H. Murray

Recently developed clay deposits that will impact regional and world markets are described. These deposits, their location, geology, and physical properties are delineated. Kaolins from the State of Para in Brazil and from Ukraine; bentonites from Argentina and India; and palygorskite and sepiolite from China are world class deposits that when processed using modem technology will produce excellent products. Other deposits that may affect regional markets are kaolins from China, Australia and Indonesia; bentonites from Georgia (formerly USSR) and China; and palygorskite from India and Ukraine. New ball clay deposits that will affect regional markets are in China and Indonesia.

Jan 1, 1999

By Lawrence E. Mannion

In southwest Wyoming lies buried the world's largest source of natural sodium carbonate, or soda ash. Perhaps a hundred billion tons of trona (sodium sesquicarbonate) are contained in ancient lake beds in the Green River basin'). There the Green River Formation encloses more than 40 extensive beds of trona. At least 25 of these exceed 3 feet (1 meter) in thickness and most of them are more than 300 square miles in extent. Five have been exposed in mines and lie between 800 and 1500 feet below the surface. Others lie at depths of from 400 to 3500 feet. Three companies have underground mines that supply trona to adjacent soda ash plants. These are the FMC Corporation, Allied Chemical Corporation, and Stauffer Chemical Company. A fourth, Texasgulf Corporation, has a mine under development. In 1974, annual soda ash capacity in the Green River area was approximately 4,300,000 tons, which requires the mining of about 7,500,000 tons of trona.

Jan 1, 1975

By Thomas G. Hayes

Track-type tractors remain one of the most cost-efficient stripping tools available to coal miners. Whether they are "sweetening up" a dragline operation with prebenching or serving as the primary tool, dozers are important in driving down mining costs. This article reviews the application zone of track-type dozers. It also provides suggestions for site setup, equipping tractors and machine operation. In recent years, the track-type tractor has become more of a production tool in mining. With the advent of bigger machines, bulldozers have become a typical component in mining operations, removing overburden down to the top seam of coal. Large tractors can also be teamed up with draglines and other systems to maximize the effectiveness of the mining system. Bulldozers remain the tool of choice for topsoil removal, spoil reclamation or any application that demands low ground pressure, or short distance. The introduction of the 523-kW (700-hp) track-type tractor to the mining industry has made the bulldozer a low-cost-per-ton means of removing overburden. The large tractors offer enough productive capability to be considered prime stripping tools. And they can lower mining costs by complementing other mining systems (dragline, cast blasting and loader/truck). Four criteria determine whether a track-type tractor is the right machine for a particular application: ? Production requirements - dozer may fit job requirements better than a second dragline. [ ] ? Product support - availability of parts, service and technical expertise. ? Labor situation - how much of the cost per ton goes to the operator. ? Resale opportunity - recover a percentage of capital cost. Mining efficiency is economically controlling the cost of any system. Most operations rate the most economical means of moving material as cast blasting, dragline and the track-type tractor. All three of these systems share one common value: They are all sensitive to distance. Regardless of the application, all mining systems have an economic range. Exceeding this distance will affect cost and productivity.

Jan 1, 1997

By Betty L. Gibbs

A clear and accurate knowledge of the status of ventilation in an underground mine is essential to continuing safe operation. In a small mine with a few working faces, the problem is simple and can easily be solved by choosing the appropriate fan. In larger, more complex mines the problem of supplying the working faces with fresh air is a problem beyond the scope of 'finger in the wind' analysis. In today's climate of stiffer government regulation and mining company concern for the safety of workers, computer programs which analyze ventilation networks are helping mining companies meet the standards. The development of computer programs for ventilation network analysis is summarized. Early programs were developed at universities or government agencies and required large expensive computers. As computers have become smaller and less expensive, the development or revision of programs for micro computers has become more available. Prices have lowered to the point of affordability even for medium and small companies. A list of ventilation network analysis programs is provided along with a summary of capabilities, costs, and hardware requirements for each program.

Jan 1, 1987

By E.C. Jong

Resumen ¦ Un sistema de comunicaciones “a través del suelo” (TTE) comercial y disponible fue evaluado en una mina de carbón subterránea en la zona Este del Estado de Kentucky. Este estudio de campo fue realizado como parte de una evaluación multisitio mayor de sistemas TTE disponibles. La mina detallada en este estudio se encontraba paralizada al momento de la evaluación, lo que proporcionó la representación más cercana a la realidad del medio ambiente en una mina luego de una operación de cierre. Para este estudio se probaron las comunicaciones superficie a subterráneo y subterráneo a superficie. El despliegue estándar del sistema TTE usando los procedimientos recomendados por el fabricante logró obtener comunicaciones claras y nítidas entre el socavón y la superficie. Otras disposiciones de las unidades arrojaron resultados mixtos. Existen planes para examinar más los fenómenos observados en esta mina.

Apr 1, 2016

By James A. Martin

In relating geology and mineral resources to the nongeologist engaged in planning and zoning, a major hurdle to overcome is often the concept of natural resources. Statements listing such "resources" generally include and often may he limited to such items as "open space", "buildings of historical value", "forest and wilderness areas", and "sites of natural beauty" but seldom mention minerals even where they are of significant economic importance to the area. Unfortunately, mention of mineral resources is often limited to statements calling for tight controls on mining to prevent "ravaging of the land". While, the concept of sequential use involving mining is sometimes acknowledged, it is frequently done in such a manner that this approach is discouraged. In the conflict for land between urban development, recreational open space and mineral extraction, far too often the mineral industry will be the loser. In Missouri, there have long been continuing requests for geologic and resource data for planning purposes from city and county government and from Federal agencies for inclusion in the various river basin studies and Soil Conservation Service projects. These reports vary in detail from concise statements of the geology of an area to rather lengthy reports on mineral and water resources, bed rock and engineering geology characteristics. In most cases, these reports as written were directed to a geologically-oriented reader. Our initial approach to presenting geologic data to the land-use planner was in the area of engineering geology with attempts to show the limitations that bedrock and soil conditions can place on development. The first formal reports, engineering geology studies of urban areas, were released by the Missouri Geological Survey in

Jan 1, 1976

Some basic terms used in cost management and accounting include: - Cost. A sacrifice made to acquire goods or services, measured by the price paid. Technically, the sacrifice is called a cost until the benefits from the goods or services have expired, at which time the sacrifice is called an expense. In this text, the terms "cost" and "expense" are used interchangeably. - Revenue. An increase in the value of the firm resulting from the sales of goods and services. - Income. The excess of revenues over costs for a specified period. The term is often used with modifiers to indicate specific quantities on an income statement (e.g., pretax income; net income). - Activity. A measure of production work. Traditionally, physical production volume (tons of ore or units of product) has been used as the measure of activity. Other measures include direct labor hours, equipment operating hours, and quantity of materials or supplies consumed. - Responsibility center. A segment of an organization that is responsible for a specified set of activities. In mining, individual operating divisions can be treated as responsibility centers, known as profit or cost centers. Departments within a division are generally treated as cost centers. - Cost center. A portion of an organization having responsibility for achieving specified levels of cost. - Profit center. A portion of an organization having responsibility for achieving specified levels of profit (revenues and costs).

Jan 1, 1999

By F. F. Peng

Fine Coal Cleaning Processes including froth flotation, aggregative flotation or oil agglomeration, depend upon the wettability of coal particles in the aqueous solution. The wettability of coals of various ranks, hydrocarbon oil treated coals and oil-agglomerates have been measured using film flotation, induction timer, and froth flotation. Various hydrocarbon collector dispersion techniques are used to alter the surface wettability of coal particles. Change in wettability behaviors, measured by flotation responses, due to various ranks with or without of hydrocarbon collector modification are explained in terms of surface chemistry modifications as analyzed by induction time, film flotation as well as DRIFT Spectroscopy. The relationship between the wettability of coals and collector treated coals, and floatability are discussed.

Jan 1, 1993

By R. Stanevich

Studies by the National Institute for Occupational Safety and Health (NIOSH) and the Bureau of Mines (BOM) have demonstrated that: (1) 90% of diesel particulate is less than one (1) micrometer in aerodynamic diameter; (2) more than 90% of the respirable mass in electric coal mines was greater than one (1) micrometer in aerodynamic diameter; and (3) in coal mines using diesel equipment, average diesel concentrations can represent up to 53% of the MRE respirable coal dust standard. For mines approaching the 2 mg/m3 standard, compliance may be easier to attain by controls directed at diesel exhaust particulate as opposed to coal dust control. First, however, a Simple instrument is needed to measure diesel exhaust particulate concentrations. This paper describes such a sampler, its construction, and use. While results from this sampler are primarily utilized to identify control areas, NIOSH is also using the sampler for estimating worker exposures in epidemiologic studies.

Jan 1, 1988

By David L. Giles

The alkalic igneous province of Montana consists of centers of laccolithic and stock-like intrusive complexes with associated sills, dikes, and breccia pipes (e.g., Judith, Highwood, Little Belt Mts.); isolated plug-like mafic bodies (e.g., Smokey and Eagle Buttes); and clusters of kimberlitic diatremes and ultrabasic dike swarms (Missouri River Breaks). The province extends in a belt throughout central Montana from the North Absaroka Range in the south to the Sweetgrass Hills on the Canadian border. Intrusive activity ranged in age from Late Cretaceous to late Miocene, peaking at about 50 m.y, ago. Diverse types of significant epithermal gold mineralization occur at many of the laccolithic centers. This mineralization took place in large part during the waning stages of, or following, igneous activity. Large remnant travertine blankets in the region attest to comparatively recent hydrothermal activity. The quartz-pyrite-gold mineralization ranges from igneous- hosted stockworks or fracture sets (Zortman-Landusky and Neihart districts) and breccia pipes (North Moccasin Mts.) to replacement zones in flanking and upwarped Madison Group limestone (Gilt Edge and Kendall districts). The latter are mostly localized by intraformational solution breccias in the upper Madison, notably near porphyry contacts. Gold mineralization in the province was accompanied by varying amounts of silver, base metals, sulfosalts, and tellurides, with quartz, fluorite, carbonate, and barite and gangue. Gold occurs as auriferous pyrite, sylvanite, or in native form. Since the 1880's, primary gold production from numerous scattered deposits in the Judith, Moccasin, and Little Rocky Mountains, along with byproduct gold from the Neihart silver district (Little Belt Mountain), has totalled around 2 million oz. The major deposits were in the 1-2 million ton range at an average gold tenor of 0.3-0.6 oz per ton. Most of the ore was mixed oxide or carbonaceous sulfide ore and was treated either by amalgamation or by roasting-cyanidation. Current activity includes heap-leach operations on bulk- tonnage low-grade (approximately 0.03 oz per ton) ores at Zortman-Landusky, and several small-scale, experimental leach or mining operations on carbonaceous replacement ores, as in the Kendall district and Spotted Horse mine. Current exploration efforts for gold are focused not only in the old established districts, but also in and around other alkalic centers, which have been unproductive to date, such as the Crazy Mountains, Sweetgrass Hills, and Bearpaw Mountains. Target concepts in these efforts are porphyry-hosted stockwork or disseminated gold ores and Carlin-type replacement lodes in the flanking Madison or other favorable carbonate units.

Jan 1, 2013

By Alan H. Goode

Of the 15 million tons of glass discarded in municipal wastes annually, about 2 million tons pass through incinerators and can be recovered by ore processing techniques. Although the primary use for this recovered waste glass would be as cullet in the manufacture of new glass containers, this approach is not always practical because of long shipping distances, high freight costs, and high purity requirements. Alternatives to the use of waste glass as cullet would be either as landfill or in secondary products. Although glass is considered a good landfill material, it is still wasteful of potentially valuable raw materials. Secondary products that can be made from waste glass1 include a variety of industrial and construction items. As part of the Bureau of Mines' program in secondary materials recovery, the Tuscaloosa Metallurgy Research Laboratory has conducted research concerned with the development of ceramic building products from waste glass. Materials employed in this research were obtained from municipal incinerator residues fractionated in the Bureau's continuous residue processing plant, College Park Metallurgy Research center.' The studies reported herein3,4 present research results using waste glass in the formulation and production of clay bricks, not only to produce improved products, but to reduce production costs, conserve natural raw materials, and most important, to reduce manufacturing energy requirements.

Jan 1, 1974

By Yousef Ghorbani, Abolfazl Danesh, Fatemeh Kazemi, Ataallah Bahrami, Morteza Abdollahi, Mohammad Raouf Hosseini

This study aims to investigate the effects of operational variables on concentrate grade, recovery, separation efficiency, and kinetic parameters of the copper flotation process. For this purpose, the effects of the pulp solids content, collector and frother dosage, and preparation and concentrate collection time were studied using a Taguchi experimental design. The results of statistical analyses indicated that the concentrate collection time and pulp density were the most influential parameters on concentrate grade. Considering copper recovery, concentrate collection time, collector dosage, and pulp density were the most significant variables, in decreasing order of importance. Also, the separation efficiency was mostly influenced by the concentrate collection time. Furthermore, kinetic studies showed that the second-order rectangular distribution model perfectly matched the experimental flotation data. The highest kinetic constant of 0.0756 s−1 was obtained from the test, which was performed with 35% solids content and 40 and 20 g/t collector and frother, respectively. The highest predicted copper recovery of 99.57% was obtained from the test at 30% solids content, and the collector and frother dosages of 40 and 15 g/t, respectively

By Richard Belair, John Read

Ask someone what they can tell you about the Royal Canadian Mint and most likely the first thing that they will mention, is coinage. The Royal Canadian Mint manufactures Canada's one-cent coins, nickels, dimes and quarters - over 1 billion per year. Most of these coins use copper and nickel as base material, and all of this metal is mined, refined and processed in Canada prior to being shipped to the mint for coin production. In 1985 alone, 1270 metric tons of Canadian nickel and 2160 metric tons of Canadian copper were absorbed in circulating coinage. July 1987 will have marked the introduction of Canada's new one dollar coin, an important new addition to Canada's monetary system. The first phase of this program will consume about 2,235 metric tons of Canadian nickel in the initial production run. Annual requirements in subsequent years are estimated at 225 metric tons. The Royal Canadian Mint is also a major producer of circulating coinage for foreign countries. Since the state-of-the-art Winnipeg plant swung into full production in 1976 the Mint has struck more than 5.2 billion coins for some 35 nations around the world. 1985 sales have increased almost 6 fold over 1984. 1987 already shows commitments for a further significant increase in volume in this business. The use of Canadian metals in export to foreign nations as coinage adds still more to the Royal Canadian Mint's key role as a major market maker for Canada's mining industry. The success of the Mint in this realm can be directly traced to it's 75 years as one of the world's most important refiners of gold. Today, the Royal Canadian Mint is the largest refiner of gold in the Western Hemisphere, and the third largest, by volume, in the world. The R.C.M. hallmark on kilo bars, 100 troy ounce comex bars

Jan 1, 1987

By Surendra Kumar Biswal, Sachida Nanda Sahu, B. C. Meikap

The unutilized iron ore fines (IOF, − 10 mm, 45% to < 60% Fe(T)) left at various mine sites during blasting and processing are rich in goethetic-hematite associated with high clay and considered a potential iron ore resource. The variation of loss on ignition (LOI) from mines to mines is based on the goethite and clay mineral content. The clay containing below 45 μm is mostly brittle, causing beneficiation problems. The IOF has an LOI of 7.83%, with high silica (5.52%) and alumina (4.57%), and 57.17% of Fe(T) subjected to both conventional deep beneficiation (CDB) and magnetization roasting using high-ash non-coking coal to adopt the suitable upgradation process. The CDB and magnetization roasting concentrate has 62.61% and 67.58% Fe(T) with 64.69% and 85.19% yield, respectively. However, the presence of 6.40% LOI in CDB makes the ore challenging for pelletization. Characterization like X-ray diffraction(XRD), scanning electron microscope(SEM), and chemical analysis was used to assess the concentrate quality and potential industrial application.

Jun 4, 2022

By G. K. Derby

Paper presents project results investigating current techniques for dragline wire rope removal and the development of less hazardous means of performing the task. The cannon is the most prevalent method used in American surface mines. A cannon test program was conducted that used 40-and 50-grain primer cord to establish force produced using a 56-pound projectile. Socketlwedges were separated to establish separation force data. Two alternative removal methods, pendulum ram and portable hydraulic pusher, were developed and tested. Both provide sufficient force to effect separations under normal conditions on draglines with up to 78- cubic yard buckets.

Jan 1, 1984

By L. Adler

When systematically compared to other engineering fields, mining engineering is distinctive in 1) having a total systems concern. 2) dealing with encumbered space and 3) requiring full spectrum practice. The total systems concern results from having to design and then co-ordinate in space and time several major systems: excavating and bulk handling, ground control, life support and normal support. This requirement favors a generalist rather than a specialist approach. In coping with encumbered space especially in underground coal mining, the uncertainties of geologic conditions are compounded by tightness, roughness, remoteness and hazards. Into this difficult setting the total systems * complex is "stuffed," adding congestion and interference. Because of significant ground deterioration a flexible "rapid in-out" approach is usually vital to mining. Full spectrum practice arises from the need to manage, as well as to plan and design, a labor intensive operation. Since market conditions can also fluctuate most aspects of administration are needed in many respects, mining engineering functions relative to civil engineering in a way similar to industrial to mechanical engineering, with encumbered space being crucial. On this basis stress is placed on: 1) personal relations, 2) field work and 3) entrepreneurship, viewing time as money. Specific recommendations for improving engineering, safety and management and leadership are made. Since most new deposits are marginal, by applying these recommendations with high technology they could possibly now be mined on a widespread basis.

Jan 1, 1985

By P. C. Thakur

Frictional ignitions (also called face ignitions) is defined as the rapid oxidation of a mixture of methane and air with a visible flame that could last from a few seconds to several minutes. These ignitions have a potential to turn into a mine explosion and eventually a large-scale mine fire. Over the last 22 years, U.S. coalmines have had 1566 frictional ignitions. There were no fatalities but serious injuries have occurred. Every effort, therefore, should be made to prevent frictional ignitions. The preventative measures fall under four categories: (a) degasification of coal seams prior to mining, (b) adequate ventilation, (c) wet cutting or water-jet assisted cutting and (d) machine design to minimize ignitions. The paper discusses each of these techniques in detail.

Jan 1, 2006