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By Russel Delmar

Construction of Ontario Power Generation?s 12.8-m diameter, 10.4-km long water diversion tunnel in Niagara Falls, Ontario, is underway. The tunnel is being excavated by means of a 14.44-m diameter open gripper Tunnel Boring Machine. The tunnel lining is constructed as a two-pass system with the initial lining consisting of rock bolts, mesh, steel channels or ribs, and shotcrete, and the final lining consisting of pre-stressed cast-in-place concrete with a waterproof membrane. This paper describes salient design and construction aspects as follows: ? Regional and Site Geology ? Tunnel Layout and Design ? TBM Tunnelling and Cast-in-place Concrete Lining Construction

Jan 1, 2008

By William O. Vanderburg

This report3/ gives the results of a reconnaissance of mining districts in Eureka County, Nevada, made from September 25 to October 20 and from October 27 to November 5, 1577. During this time, virtually all the districts were visited and many data obtained on active and inactive properties. This report covers the locations of the various districts, geological background, ownership and brief descriptions of mines and prospects, information on past and current operations, and, other data likely to be useful to those interested in the development of our mineral resources. From the viewpoint of past production in the county, the silver-lead-gold deposits at Eureka have been tie most important, followed by the silver deposits at Cortez and Mineral Hill. The period of greatest activity in the foregoing districts was from 1870 to 1990, when Eureka was one of the principal mining areas in Nevada; the production of lead was sufficient to affect its price in all the commercial centers of the world. Eureka also merits the distinction of being the birthplace of the silver-lead smelting industry in the United States.

Jan 1, 1938

By Tony Lipiec, Greg Gosson

"When it comes to new mines being developed, there is a general industry consensus that most low-hanging fruit has been picked. Many projects currently in the mine development pipeline have been around for decades, but were held back because of technical challenges. Future development of these deposits will likely require access to the public capital markets, and in Canada that means providing scientific and technical disclosure on these deposits in compliance with NI 43-101. As many of these “challenged” projects have metallurgical issues, the companies that own the projects need to ensure their metallurgical Qualified Persons provide transparent disclosure regarding proposed solutions to those issues.This paper provides an overview of the disclosure requirements under NI 43-101 that are pertinent to metallurgists, and other Qualified Persons who prepare technical disclosure regarding the metallurgical characteristics of a mineral project. It lists the triggers for a technical report under NI 43-101 and Canadian stock exchange policies, and identifies the sections of the report that should involve input from a metallurgist or process engineer. It briefly outlines new civil liabilities under Canadian securities laws that increase the possible consequences for not complying with the technical disclosure standards.These materials are provided for general information purposes only and do not constitute legal advice. Readers are advised to seek specific legal advice from their own legal counsel in relation to any decision or course of action contemplated."

Jan 1, 2003

By B. K. Shibler, K. C. Vincent, W. W. Agey

"INTRODUCTION As a part of the investigation of domestic manganese deposits, examining engineers of the Bureau of Mines collected samples of ore from three from three properties in the general vicinity of Tracy, Calif.The Buckeye mine is 23 miles of Tracy, just inside the northeast boundary of Stanislaus County. The mine is owned by K.O. Winship estate of San Francisco and is leased by Verner Allen, also of San Francisco.The ore is principally manganese carbonate occurring in interbedded layers in white chert, with the original,carbonate mineral altered in place. Four samples, representing four types of ore, were submitted, as follows: A, black oxide; B, pink carbonate; C, gray carbonate.The Wilfred Murphy property (also known as the Murmac claims) is approximately 30 airline miles south of Tracy. The property can be reached by road from either Livermore or Patterson and is on the divide separating Santa Clara and Stanislaua Counties Calif. The ore occurs in lenses along a white-chert formation. A 2-ton sample of ore for testing was taken from a dump accumulated from assessment and development work. The Ladd mine, 13 miles from Tracy in San Joaquin County is owned by Pat J. Connolly of Tracy and is leased by Mack C. Lake of San Francisco. The ore is essentially a chert impregnated with manganese oxides and the association is therefore exceedingly intimate and complex. Samples from each of the three adit levels of the mine were submitted for ore-dressing study.As the samples differed widely in physical character and response to ore-dressing methods of treatment, beneficiation of ores from each property was considered as a separate problem. Hence results of the investigations will be prescribed in separate sections of this report."

Nov 1, 1947

By Parker JB

The Channar Iron Ore Mining Project (the Project) is a joint venture involving the Hamersley Holdings group (Hamersley) and the China Metallurgical Import and Export Corporation (CMIEC). The Project represents the first new iron ore mine development in Australia since 1971/72 and is the first major overseas mining investment by the People's Republic of China (PRC). The Channar mine is being constructed in the Pilbara region of Western Australia and will operate for more than 20 years supplying the PRC with 200 M tonne of high grade iron ore. The Project is configured to take advantage of Hamersley's existing production and support facilities. The Joint Venturers will invest A$280 million to achieve an initial production rate of 3 M tonne/yr and an additional A$120 million over the next 8 years to achieve full capacity of 10 M tonne/yr. Financing the Project to meet the requirements of both Hamersley and CMIEC, with the dependance of the Project on Hamersley's infrastructure, and in a depressed iron ore market, required an innovative financial structure to be arranged in a limited period. This paper describes both the financial structure and its implementation, and draws a number of conclusions regarding the financing of resource projects.

Jan 1, 1989

By W. F. Boericke

WORLD production of silver in 1929 totaled 256 million ounces. In 1928 production was 258 million ounces, and in 1927, 254 million ounces. With an actual decrease in the amount of silver produced last year, as compared with 1928, and an increase over 1927 of less than one per cent, obviously there has been no overproduction of the metal in the popular sense. But the price of silver tells a different story. For 1927, the average quotation was 56.37 cents; it was 58.17 in 1928, and 53.0 in 1929. During the last year it reached a high point of 57 cents in January, and fell steadily, without interruption to the downward trend, to a low of 47 cents in December. Since then it has dropped to an all time low of 43 cents on February 6.

Jan 1, 1930

By A. C. Fieldner, W. A. Selvig

Information concerning the fusibility of coal ash has become of considerable value to the consumer of coal, mainly in connection with the troublesome formation of clinker resulting from the melting of the ash constituents of the burning coal. The growing interest in such data has led the Bureau of Mines to make a general survey of the "fusing" or "softening" temperatures of the ash from coals of the United States. It is hoped that this information when used together with the large number of coal analyses published 1 by the bureau will assist the consumer of coal in comparing different coals, and in selecting the coal best adapted for his purpose.

Jan 1, 1922

By Paul Miranda, Corby Anderson

"The Center for Advanced Mineral and Metallurgical Processing (CAMP) has recently obtained a Mineral Liberation Analyzer (MLA). CAMP has utilized the technology for several projects with excellent results. The MLA is able to both analyze size and quantify mineral phases. Therefore, the MLA is becoming the Sherlock Holmes of the mining and metallurgical industry. For this presentation, four projects have been evaluated and data was collected using the MLA. The first project involved tungsten mine. Previous mining practices have yielded poor tungsten results and recoveries. By using the MLA, tungsten mineral phases, along with possible contaminants, were verified and the results used to try to increase overall tungsten recoveries. The second project evaluated a molybdenite/chalcopyrite concentrate with surprising results. The third project is a silver project. Initial flotation scoping tests were performed by attempting to separate silver from gangue material. Because of the poor recovery results (less than 5%), MLA was used to determine possible scenarios for increasing silver recovery. Finally, the last project involves gold evaluation in tailings. For all projects, MLA application results will be presentedand discussed.INTRODUCTIONThe Center for Advanced Mineral and Metallurgical Processing (CAMP) has recently received a software add-on to a scanning electron microscope (SEM) located at Montana Tech. The Mineral Liberation Analyzer (MLA) technology was developed by Dr. Ying Gu of the JKTech Center of the University of Queensland. Since August 2006, CAMP has received and processed over 50 samples. These samples include a total mineralogy of tungsten ore samples, gold tailings, lead zinc tailings pile, molybdenite concentrates, copper concentrates, as well as others. During analysis of these received samples, the technology allows the samples to be quantified mineralogically with some surprising results.For analysis, the samples were initially sieved between 170 to 200 screen sized mesh. This ensures that received samples mineral size is fairly uniform. The samples are then placed into epoxy and allowed to harden. Next, the samples are polished and carbon coated for MLA analysis."

Jan 1, 2007

By John Plecash

This paper comprises a general outline of all of the developments, including the history, geology, mining, milling, power and transportation installations, at the gold mining operation of La Luz Mines Limited and the copper mining operation of its wholly-owned subsidiary, Rosita Mines Limited, both located in north-central Nicaragua. The low-grade, gold-bearing ore-bodies of La Luz Mines, contained in highly fractured and folded Lower Cretaceous sedimentary rocks, were from 1909 to 1928, mined and treated by primitive methods by the La Luz and Los Angeles Mining Company. The abandoned property was acquired by La Luz Mines Limited in 1936, and was equipped with modern machinery and put into production in 1939. Between 1939 and 1948, the daily rate of production was in-creased from 300 tons per day to 2,-000 ton per day. The ore reserves available for open-pit mining were depleted in 1954. Since then, the entire production has come from under-ground operations.

Jan 1, 1963

By R. E. Vivas, J. A. Villa

"Located in the state of Colima, Peña Colorada is one of the largest iron ore operations in Mexico. The project is owned in equal parts by ArcelorMittal and Ternium. Though boasting a production capacity of 4.1 Mt/a (4.5 million stpy) of concentrate per year, Peña Colorada is faced with declining ore grades. In order to respond to this situation, Peña Colorada had to expand production even further. This expansion created various challenges that were overcome by the adoption and application of new technology. Examples of these technological innovations are discussed in detail in this article and include improvements in geo-modeling, mine planning, and mine operations. The successful implementation of these technologies paid for itself many times over, and has led to significant improvements in production and performance, while lowering the operating costs and reducing the variance between planning and execution.Project overviewPeña Colorada is a mining company that produces about 30 percent of the iron ore in Mexico. This project generates about 1,200 direct jobs and 3,000 indirect jobs, making a significant contribution to the local economy. Similarly, Peña Colorada invests in its local communities through numerous educational programs, scholarships, university agreements, social development, environmental agreements, etc. Peña Colorada’s operations consist of an open pit mine located in Minatitlán and a pellet plant located in the port city of Manzanillo, as shown in Fig. 1. Technological innovationsMost mining projects around the world typically follow the logic of “mining the next best ore.” Consequently, head grades tend to decline over the life of the mine. In the case of Peña Colorada, a decline in head grade combined with a decline in iron ore prices forced the operation to adapt to a new business environment and adopt new technologies to face these challenges. However, the first step along this process was to increase the confidence and reliability of the resource model. This task involved additional drillhole campaigns coupled with more detailed modeling techniques. Once the block model was completed, new optimization studies and production schedules were evaluated with new optimization tools that improved many aspects of the mine plan. The Peña Colorada block model has undergone 3 expansions to reflect additional information not available in the past. The model has expanded to the East and Southwest. The latest model expansion increased the total number of benches to 98 as a result of positive exploration results. Similarly, new geotechnical studies were prepared, which provided new guidelines for pit slope design, and new technology was implemented to monitor ground movement and slope stability. Two sectional block model views in Hexagon Mining’s MineSight 3D, along with the pit designs and geologic solids are shown in Fig. 2."

Feb 1, 2017

By George A. Lawrence, J. C. McHardy

"Field operating experience with an improved flotation mechanism for handling various flotation applications is covered in this paper. Some aspects of designing flotation machines are also presented. Operating data from extensive testing of commercial size equipment under actual plant operating conditions in the following applications is detailed:1. Copper Flotation2. Fine Coal Flotation3. Base Metal Sulfide FlotationDesign features, design improvements, modifications tested, and overall performance data are reviewed. Some mecl1anical performance data as well as metallurgical performance results are presented. Some comparisons with conventional flotation equipment are reported in this paper.Flotation sizing theories are reviewed and an actual equipment selection ex2.mple is presented. Scale-up criteria used for developing large cells are briefly covered.The paper concludes with a brief review of anticipated future flotation equipment design needs. IntroductionThe mining/milling industry is faced with increasing pressure to cut costs while maintaining product quality and indeed, in some instances, expanding production. For copper, nickel, iron, molybdenum, lead and zinc sulphides, coal, phosphate and some other minerals;, flotation remains the primary method of concentration and recovery of the valuable mineral away from the gangue. Cost reduction in flotation can be broadly focused on two areas:1. Flotation Chemicals2. Flotation Equipment"

Jan 1, 1985

By K. L. Paciorek

The primary objective of this final phase of Contract No. H0133004 was to provide a description of all experimental assemblies and procedures used throughout this project in such a detail as to permit duplication of the tests in any other laboratory. A further objective was to summarize and evaluate all results generated throughout the duration of this program and to tabulate all the materials and data in such a manner as to allow this report to be used as a reference index for specific compositions or groups of compositions regarding potential hazards arising from their use .in underground coal mining operations. The report also contains an updated survey of the literature on thermal oxidative degradation of compositions investigated under this contract.

Jan 1, 1978

By S. Ndlovu, M. Malatse

"The Witwatersrand Basin is the heart of South Africa’a gold mining industry. The cluster of gold mines located in the Witwatersrand Basin generates a significant amount of mine tailings, which have adverse effects on the environment and ecological systems. In addition, disposal costs are very high. The exponential population growth in the Witwatersrand area has resulted in pressure on the reserves of traditional building materials. Quarrying for natural construction material is very expensive and damages the landscape. This work therefore examines the use of gold mine tailings in the production of bricks.Different mixing ratios of gold tailings, cement, and water were used. The resulting bricks were then cured in three different environments - sun dried, oven dried at 360°C, and cured in water for 24 hours. The bricks were then tested for unconfined compressive strength, water absorption, and weight loss. The results showed that the mixture with more cement than tailings had a compressive strength of approximately 530 kN/m2. It was also found that the best brick curing system was in a water environment. Bricks made from tailings cost more than conventional bricks because of the higher quantity of cement used, but the manufacturing process consumes less water. Overall, the results indicated that gold mine tailings have a high potential to substitute for the natural materials currently used in brickmaking.Paper written on project work carried out in partial fulfilment of BSc. Eng. (Metallurgyand Materials Sciences)"

Jan 1, 2015

I had hoped when the time came for me to address this meeting that gold mining would be in a much happier position than we find it to-day.As it is, and because of the demands of national security, we find this great and valuable primary industry relegated to the background and in danger of temporary extinction.These notes refer mainly to gold mining in Western Australia, whence comes the major portion of Australia's production, and their purpose is to record a brief review of the industry immediately prior to the general disorganization that is following the call-up of men from the mines.During this period of reduced production the loss of comparable statistical data will make it impossible to follow the progress of the industry, and, since the period may be long, it occurred to me that information might be derived from an examination of the trend of recent production that would indicate what may be expected of the industry when full production is resumed in the future.Since the revival of gold mining, which started in 1931, most of the old-established mines have reorganized and, in some cases, completely renewed and enlarged their equipment in order to achieve maximum production, and old mines hitherto unpayable have been re-opened and equipped. At the same time large sums have been spent in scientific prospecting and in search for new mines, and it is safe to say that at the end of 1939, when gold production reached its peak, practically every known mine in Western Australia that could be worked profitably was in production.During this period the number of men employed in the industry rose from 5,961 in 1931 to approximately 15,000 in 1939. From the outbreak of war in 1939 to the end of 1941 the output from the mines was maintained at full pressure, maximum tonnage beingrecorded in 1940, although a reduction in the grade of ore treated caused a slight falling off in gold production.During 1941 there was a. fall in both tonnage and grade. The decline in tonnage was due partly to the closing of the Lancefield and Mount Magnet mines, and partly to the shortage of labour brought about by the response of the goldfields to the call for men for the fighting services, the average number of men in the industry in this year being reduced to 12,929.With the entry of the United States into the war in December last and the pooling of the resources of the allied nations, the need for gold as a purchasing medium passed, and with its passing there arose the demand for the transfer of the man-power engaged in gold mining to other fields of industry directly connected with the war effort.There was a ready response by those connected with the industry who...

Jan 1, 1942

By M. Hitch, M. B. Lytle

Resource development conflicts arise largely due to differences in worldview between those who support and those who oppose development. This paper illustrates how societies and civilizations with different worldviews produce different levels of creative and economic energy. A questionnaire was created to build a database of responses to test whether worldview and resource development are correlated. Factor and multivariate regression analysis determined correlations for respondent groupings. Results showed a positive correlation between the respondents\u2019 worldviews and their attitudes toward resource development. Correlations became stronger as the homogeneity of the sample subgroups increased.

Jan 1, 2017

By Joe Pezo

Desde 1999 se desarrollaron pruebas de lixiviación de concentrados en la planta LESDE de Toquepala con el propósito de evaluar las recuperaciones y los tiempos de procesamiento. Las recuperaciones a nivel laboratorio indican que la promoción de la actividad bacteriana es uno de los factores para acelerar el proceso de solubilización del cobre calcopiritico del concentrado. La actividad bacteriana se define como la capacidad de adaptación que tienen las bacterias en medios lixiviantes para elevar la velocidad de oxidación del ión ferroso y convertirlo en férrico y es el mecanismo para la lixiviación del sulfuro primario o calcopirita, el resultado de la interacción de las bacterias ferrooxidantes, el oxígeno y el control de ácido que mantienen un pH por debajo de 2.1. En ese sentido, el presente texto señala las pruebas de lixiviación de concentrados que incluyen estos últimos conceptos, con el objetivo de evaluar la factibilidad técnica y económica de obtener licores de cobre que puedan ser aprovechados utilizando la capacidad existente de extracción por solventes y electrodepositación de la planta LESDE Toquepala.

Sep 12, 2005

By G. M. Cresswell

The 2 360 t/h two module Phola coal preparation plant represents anew era of large plant in the Witbank coalfield designed to extend its life to 2020 and beyond. The plant uses the optimum processing model for Witbank coals, receiving a feed coal size of -50 mm, wet screening it into coarse and small coal fractions 50 x12 and 12 x0.63 mm before processing them in parallel through two primary DM cyclone sections, in order to make a 27.5 MJ/kg export floats product. The sinks are processed through a common high density DM cyclone section to produce a 21.5?23 MJ/kg thermal coal middlings product. The plant design incorporates the largest size DMS equipment used to date in South African coal preparation plants, i.e. 1 150 mm large diameter pump fed DM cyclones and 4.2 m width banana screens. The fine coal is conventionally processed by spirals, whereas the raw coal slimes are filtered using automated plate and frame filter presses and added to either the middlings or discards depending on its quality. The paper describes the database, innovative design concepts, construction, and commissioning.

Jan 1, 2010

By T. T. Tomimatsu

This? Bureau of Mines paper discusses the corporate structure dynamics, methods of financing, and financial assessment approaches that should be utilized to evaluate the economic health of the coal industry. It suggests rates of return and other measures of corporate economies necessary to attract capital required to finance emerging coal demand, plus impact of coal sales to total revenues. The study illuminates the activities of 30 selected coal-producing companies, including their subsidiaries or affiliates, that were responsible for approximately 60 percent of the total U.S. production in 1974. The selected firms are not all primary coal producers; many of the larger producer's are classified by the financial institutions as petroleum, metal, and steel producers, public utilities, or chemical industries. The bituminous coal industry is highly competitive as to price, service, and quality of pronuct and is subject to competition from other noncoal energy sources. The top 15 bituminous coal-producing companies mined about 46.6 per-cent of the Nation's total production in 1974, and the balance of approximately 3,885 companies were responsible for the rest of the production. Thus, the U.S. bituminous coal industry is not an oligopoly. Today, about 65 percent of the Nation's total coal production is consumed by electric power utilities and 26 percent by steel, space heating, and other industries; the balance of 9 percent is exported.

Jan 1, 1976

By David B. Paul

"ABSTRACTThe US Army Corps of Engineers (USACE) has 704 dams in their inventory and over 100,000 miles of levees with a capital value of over $150 billion. Currently, there are 319 dams that are classified as high hazard and have actionable failure modes that will require structural modifications. The most frequent actionable failure mode associated with the inventory is seepage and piping. One of the most effective engineering solutions is the installation of a cutoff to limit seepage. Currently, USACE has over $1.5 Billion of cutoff wall projects under construction and/or design. Given the magnitude of the dam and levee safety issues, USACE is developing a new Engineering Manual (EM) titled “Seepage Control Cutoffs for Dams and Levees.” This EM covers all of the methods to construct cutoff walls. USACE has partnered with the Deep Foundation Institute (DFI) in preparation of the EM to ensure that it is comprehensive and draws from the expertise of the specialty foundation engineering companies that design, manufacture, and construct seepage control cutoffs around the world. The EM contains case histories as well as a comprehensive project statistical summary and guide specification paragraphs. The goal of USACE was to make the EM a state of the art document for use by Districts.HISTORYSlurry wall construction techniques were developed in the late 1940’s in Italy by ICOS. The first use of the slurry trench method of construction in the United States was by the USACE Memphis District in September 1945, to form a partial cutoff along the Mississippi River levee on the Arkansas side of the river just below Memphis, Tennessee. The idea for the project probably evolved from the use at that time of puddle clay trench cutoffs combined with the use of drilling mud for advancing borings. A paddle wheel mixing device was constructed for making slurry from native clays. Trenches were dug to a 20-ft depth using a trenching machine and to a 35-ft depth using a dragline with a 100-ft boom and 2-cu-yd bucket. Backfill was mixed in windrows at the site from hauled-in clay gravel and native materials and pushed into the trench by a bulldozer when the length of the trench was equal to about twice the trench depth. It is amazing that after almost 70 years, the technique is still about the same as it was when first developed by the Memphis District. A soilbentonite cutoff was constructed under the Kennewick Levee adjacent to the Columbia River as part of the McNary Dam Project in Washington by the Walla Walla District in 1952 The first application of a soil-bentonite slurry trench cutoff for control of underseepage at a major earth dam was at Wanapum Dam on the Columbia River in Washington in 1959.The first cement- bentonite cutoff in the United States was constructed at the Tilden Tailings Project to store tailings from the Tilden Mine in Michigan in 1976. The first cement-bentonite cutoff constructed at a dam on a river retaining a reservoir in the United States was completed in 1978 at the Elgo Dam (formerly the San Carlos Dam) in Arizona.The USACE has designed and constructed some of the deepest and most complex cutoff walls for dams since the 1970’s. The first major concrete panel cutoff wall constructed in a dam in the United States was at Wolf Creek Dam (Nashville District) by the ICOS Corporation between 1974-77. The dam has a long history of seepage issues associated with the karst geology that comprises the foundation. In 1968, about 17 years after first being impounded, wet areas, muddy flows in the tailrace and sinkholes in the downstream toe adjacent to the switchyard occurred."

Jan 1, 2014

By G. B. Glass

In 1996, 92.5% or 233 Mt (257.4 million st) of coal produced in Wyoming came from the Wyodak coal zone in the eastern Powder River Coal Field. While the mined portions of the zone consist of one to three beds of coal with an aggregate thickness between 15 and 33.5 m (50 and 110 ft), the thickest expression is 61 m (200 ft). The delivered coal from this zone averages 0.33% sulfur, 5.12% ash, and 19.98 MJ/kg (8,590 Btu/lb). This coal zone occurs at or near the top of the Paleocene Fort Union Formation, which is overlain by the Eocene Wasatch Formation. There is also production from two coal beds in the lower portion of the Wasatch at the southern end of the basin. Production of coalbed methane derived from the Wyodak coal zone is currently an estimated 10.2 billion cu ft a year. This production is occurring just west and downdip from the coal mines and is increasing each year.

Jan 1, 1998