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By Gary E. Sherman

To aid the U.S. Army Corps of Engineers In their Resource Development Navigation Study, the U.S. Bureau of Mines (Bureau) examined the potential for mineral development near ten Alaska port sites. This report presents the results for the first three sites: Bethel, Kivalina (Red Dog), and Omalik Lagoon. The mineral deposits near Bethel are primarily gold and mercury; the nearest deposit being 55 mites away. Because of the expense of constructing and maintaining a road over the poorly drained lowlands, the potential of Bethel as a port site in the near-term is considered to be low. The Kivalina site currently serves the Red Dog mine and has the potential to handle material for similar deposits in the area. Results from a lead-zinc mine model indicate that potential for additional mine development exists in the area. Coal is the major deposit type found near the Omalik Lagoon site. Due to environmental constraints, development of a large-scale mine producing coal for export is considered unlikely. A small-scale coal mine model was used to examine the feasibility of producing coal for regional use. This alternative may be feasible but would require conversion of heating/generating equipment in the area.

Jan 1, 2011

By Carlton E. Brown

Impinger dust-counting methods are used by industrial hygienists for determining the number concentration of unhygienic siliceous dusts in industrial atmospheres. Various statements have been made regarding the size of the smallest particles revealed by the microscopic employed in such determinations. Published data on the subject are quite limited. This report presents information on the size of the smallest particles revealed by light-field and dark-field techniques applied to impinger and electric precipitator samples collected from experimentally established aerosols of silica dust and bituminous-coal dust. Size distribution and number concentration of particles of the various sizes in the aerosols were determined from samples collected by thermal precipitation simultaneously with the impinger and electric precipitator samples. The size of the smallest silica and bituminous-coal dust particles determined in the light-field counting method used was about 1./1, . There was relatively little variation in the values from 8 impinger and 33 A.-C. precipitator samples of silica dust and 13 impinger and 13 A.-C. precipitator samples of coal dust. The coefficients of variation of the values from the four sets of determinations were low, ranging from ± 7.7 to t 10 percent. This size of 1,14 is close to the limit of resolution of the microscopic method used and to various previously suggested values. The size of the particles determined in the dark-field counting method used was smaller than the size (about 0.28A ) of the smallest particles determined in the light-field, oil-immersion method used for the thermal precipitator samples.

Jan 1, 1951

By HUNTINGTON ADANS

(Wilkes-Barre Meeting, June, 1911.) THE arrangement of a flow of cyanide-pulp through Pachuca tanks in agitation, so as to permit a continuous process, instead of alternate filling, agitation, and emptying, has been proposed by various writers within the last two years, and more particularly by A. T. Grothe, agent for the Brown patents on Pachuca tanks in Mexico. It was first put into practice, I believe, by M. H. Kuryla at the Esperanza mine in El Oro, Mexico. The starting of agitation in Pachuca tanks after filling may offer no serious difficulties with ores which do not settle rapidly in such tall tanks; and the adaptation of the tanks to continuous agitation under such conditions may give simply a somewhat more convenient method of treatment and greater agitation-capacity for a given number of tanks, because of the saving -of time lost in filling and discharging. But in the treatment .of pulp which tends to settle rapidly, as in the cyaniding of concentrates or of the whole pulp of ores containing heavy sulphides, the packing of the slime at the bottom may, cause much trouble. The use of the radial air-pipe attachments near the top of the cone and of the air-valve outside of the air-lift .tube at the bottom may obviate the difficulty to some extent; but the action of the radial air-pipes on the cone-sides is that -of a sand-blast, and their continuous use cuts through the tanks. Moreover, even when these pipes are used, some pulps will pack tightly below them in the cones. Under such conditions the use of Pachuca tanks with intermittent filling and discharging becomes a troublesome process. Time is lost in ,starting agitation; large quantities of compressed air are wasted; pulp is blown over the tank-tops; and not infrequently it may be necessary to dig out the bottoms of tanks by hand. This trouble is the only important one occurring in the use of Pachuca tanks; and, since it is caused by intermittent filling, the .arrangement of a continuous flow of pulp from tank to tank,

Aug 1, 1911

By A. Cecala, J. Noll, J. Hummer

"NIOSH has observed that many control rooms and operator compartments in the US mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room which had no cleaning system for intake air, a filtration/pressurization system originally designed for enclosed cabs was modified and installed. Eighty-seven percent of submicron particles were reduced by the system at static conditions, meaning that greater than eighty-seven percent of respirable dust particles should be reduced. The particle size distribution for respirable dust particles are greater than for submicron particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced which is an important component for an effective system and minimizes particles (e.g. dust) from entering into the room. The intake airflow was around 118 cfm, which is greater than the airflow suggested by ASHRAE for acceptable indoor air quality. INTRODUCTION Chronic overexposure to respirable silica dust (particle diameter < 10 microns) leads to a progressive lung disease known as silicosis. Workers who develop silicosis have an increased incidence of lung cancer and pulmonary disorders. In June 1997, the International Agency for Research on Cancer (1) found sufficient evidence to declare that inhaled crystalline silica in the form of quartz and cristobalite is carcinogenic. Mining is one of the leading industries for occupational exposure to silica dust (2-7). Control rooms located in dusty areas in some mines are of particular concern (8). Many mineral processing operations utilize operator’s compartments and/or control rooms to house workers who are performing particular job functions. Most industrial processing mills have rooms where a worker looks out over the facility and has direct control over the product flow throughout the entire building. In addition, primary crusher operators are often located in a compartment from which they are able to view the primary crushing function. Their job is to control when trucks dump into the primary jaw crusher and the rate of feed of the ore from the hopper into the crusher. Many of these control rooms and operator booths do not have filtration systems capable of cleaning air entering the control room or booth, which can result in elevated concentrations of dust in the room or booth. To reduce the dust concentrations in these rooms, it would make sense to clean the entering air with filtration/pressurization units similar to those proven to provide a clean environment in enclosed cabs."

Jan 1, 2016

This project, "Analysis of Men, Materials and Supplies Handling Systems in Underground Metal and Nonmetal Mines" documents the productivity and safety aspects of the existing equipment and systems utilized in transporting personnel and supplies from the surface to the underground production work place. The Present Systems Study (this text -Volume II) documents the productivity and safety of existing men and material movement systems for six representative underground metal and nonmetal mines. Identification of common problem areas was performed using recognized industrial engineering techniques. The back-up data for the industrial engineering analysis of each mine is included as respective appendices (Volume III). A summary of the study background material, six mines&apos; problem areas, comparison of problem areas, problem analysis, and solution recommendations are included as the project final report (Volume I), bound under separate cover.

Jan 1, 1975

By Robert L. Lagace

A prototype adaptive volume control for the loudspeaker output of mine trolley carrier phones was designed, built, and tested in the laboratory and in a mine. This volume control senses, and adapts to, the ambient acoustic noise environment in such a way as to produce a loud sound output under noisy conditions, and a quieter output under quiet conditions, thereby producing an understandable and unstartling volume level under all noise conditions. The design approach, prototype hardware, and test results are described, and the device is shown to be feasible for in-mine operations. The circuit design principles are easily applicable to currently available mina trolley carrier phones. Recommendations for practical improvements are included. An in-mine experiment to assess the practical feasibility and utility of the dedicated wire technique for overcoming poor trolley carrier phone system performance was designed, performed, and evaluated. The technique involves the use of a single, low-loss, properly terminated auxiliary wire, placed in the rail haulageway, which allows signals to naturally couple to and from the trolley wire/rail transmission line, and thereby significantly decrease the overall signal attenuation rate on the trolley wire/rail line. The in-mine dedicated wire experiment, results, and conclusions are described, and the technique is shown to be a valid and practical one for significantly Improving carrier phone system performance in mines. Guidelines for the installation and use of the dedicated wire are provided. Recommendations are made for obtaining further practical information on its performance and utility. A second in-mine experiment to assess the feasibility and utility of the low-impedance (low-Z) line technique for overcoming poor carrier phone signal transmission in mines was designed, performed and evaluated. The low-Z line technique involves the periodic connection of shunt capacitors between the trolley wire and the rail to artificially lower the line characteristic impedance. This causes the low impedance shunt loads encountered across the trolley wire/rail line to be less mismatched to the line, thereby reducing the overall attenuation of carrier phone signals. The results of in-mine experiments performed along unenergized and fully operational sections of trolley wire/rail line are described. The experiments were designed to measure line parameter such as inductance and capacitance per unit length, characteristic impedance, and propagation phase velocity, in addition to signal strength versus distance behavior under normal and low-Z line conditions. The low-Z line technique is shown to be valid, but not as practical as the dedicated wire technique which is recommended as the most favorable for most coal mine applications.

Jan 1, 1979

One of the critical challenges facing the mining industry ? and not just in the United States ? is the looming labor shortage. A significant percentage of the industry?s professional workforce is, well, getting old, and many will be retiring in the next 10 years or so. This is not a new issue to the industry. It has been discussed at various industry meetings and conferences for many years. How does mining, with its largely negative public image, attract young people to mining schools? And, equally important, who is going to teach them? Mining schools, what?s left of them in the United States, are beginning to lose qualified faculty to retirements, and no one is available to replace them. SME addressed this issue during the keynote session at its annual meeting in February in Denver, CO. This year?s theme was ?Mining: It?s About the People.? Despite a blizzard that blanketed the city on the day most attendees were to have arrived, the meeting still attracted a record 7,202 people. And the accompanying exhibit sold 822 booths, also a record. The U.S. Department of Energy?s National Energy Technology Laboratory contracted with the National Academies? National Research Council to complete a study concerning the availability of skilled workers to meet the energy and mineral security requirements for the United States. The National Research Council, in turn, asked SME to collect and analyze workforce trends in these industries. The result of SME?s analysis is the report ?Emerging Workforce Trends in the U.S. Energy and Minerals Industries.? It is available on the SME website, www.smenet.org. Click on Government Affairs. While the report did not paint a completely dismal picture, there were some disturbing results. It concluded that within 20 years there will not be a sufficient number of skilled professionals to satisfy the labor demand. That said, the report said that most of those positions would likely be filled. However, the U.S. mining will go through a period of time when the workforce will be made up of very young and senior workers.

Jun 1, 2013

By J. F. Burr, D. Snyder, W. Calder

This paper provides a determination of the equivalent level of protection of the international standards relative to similar criteria used by the U.S. Mine Safety and Health Administration (MSHA) to approve two-fault intrinsically safe (IS) stand-alone equipment. U.S. mining law requires such a determination for MSHA to use alternatives to existing standards. The primary issue is to demonstrate that the international standards for equipment evaluation will provide at least the same level of protection for miners as the document currently used by MSHA.

Jan 1, 2018

By J. F. Burr, D. Snyder, W. Calder

This paper provides a determination of the equivalent level of protection of the international standards relative to similar criteria used by the U.S. Mine Safety and Health Administration (MSHA) to approve two-fault intrinsically safe (IS) stand-alone equipment. U.S. mining law requires such a determination for MSHA to use alternatives to existing standards. The primary issue is to demonstrate that the international standards for equipment evaluation will provide at least the same level of protection for miners as the document currently used by MSHA.

Jan 1, 2017

By Bill Dershowitz

Consider a deep gold orebody with grade of 4 g/t (0.11 oz/st). At the time of this writing, with gold prices at historic highs, it could be a good, but not great, prospect. But if it is a vein deposit, and those veins are 200 g/t (5.8 oz/st), it would be significantly more attractive if there was a way to produce directly from those veins, leaving the rest of the rock in place. [Figure 1 The red around each of the four injector wells shows areas of high pressure, where the lixiviant fluid is pumped into the rock mass, with orange and yellow indicating dissipated pressure. The black lines indicate some of the fracture pathways through which the lixiviant, with absorbed metal, flows toward the central recovery well where low pressure is indicated in blue. Lixiviant is pumped out through the recovery well. Image courtesy of Golder Associates.] There is a way to do this, in situ leach (ISL) or solution mining. It has been a viable commercial technology for more than five decades.

Jan 1, 2011

By M Taylor

The Project Specification and Technical Requirements documents associated with several recent large road tunnel projects within Australia have specified the application of AS/IEC 61508 – FunctionalSafety of Electrical/Electronic/Programmable Electronic Safety Related Systems at very high performance levels for the various control and fire life safety systems associated with such facilities.This paper seeks to explore the implications of referencing this standard within the road tunnel services context in terms of practicality, complexity and cost, whilst providing some examples of how a high safety integrity level (SIL) level can theoretically be achieved given current hardware availability.

Mar 8, 2011

By A. C. Butterworth

M OST operators of open-pit mines in the Lake Superior iron ore district are quite familiar with the use of fuel oil in the heavy-duty Diesel engines commonly used in truck-haulage service but some operators, including my own company, Pickands Mather, have had butane-engine trucks in service for several years, and less is known of their operation. One of the first installations of trucks for iron-ore haulage was in 1939 at a deep open-pit mine on the Cuyuna Range. These superseded standard-gauge steam haulage. Trucks then obtainable were equipped with 150-hp Diesel engines, and the speed of these units on an 8 % grade would have been so slow, considering the depth of the pit, that plans for an all-truck haul out of the pit were rejected. About this time one of the engine manufacturers brought out an auto-

Jan 1, 1948

By J. A. Russell

MR. M. W. Boom: I would like to congratulate Mr. Russell on his fine paper. One very good point which has always appealed to me is the smooth working of a steam hoist as compared with electrical. He does not mention the steam hoist at Springhill which has been working there for a good many years. MR. S. R. NEWTON: I have read with a great deal of interest the paper presented by Mr. Russell on the development of haulage engines in the mines of the Dominion Steel & Coal Corporation. He is to be congratulated on having produced a comprehensive article showing, step by step, the various improvements that have been made over the years in the design of such engines. I am quite in accord with Mr. Russell&apos;s statement that the positive tooth clutch can have too many teeth, and also that the method of driving a sliding clutch hub of any design should be by means of a hexagon or octagon on the shaft. Where the clutch hub does not of necessity slide on the shaft it can be pressed on and keyed to the shaft in the normal manner. With regard to the &apos;Cramp&apos; internal-expanding jaw-type clutch, while it is true there are more moving parts than with the clutch consisting of a ring with internal cut teeth and a driver having a fewer number of teeth as .described by Mr. Russell; there are compensating advantages to the internal expanding jaw-type of clutch. The V shaped profile of the teeth permits of engagement of the clutch with very much less &apos;jockeying&apos; of the drum. This is particularly the case in vertical-lift mine hoists, where it may be necessary to engage and disengage the clutching mechanism at frequent intervals.

Jan 1, 1944

Prevention of coal-mine explosions depends largely upon thorough knowledge of the causes that initiate explosions. A review of coal-mine explosions in one geographical area when supplemented by nationwide data of similar nature, should serve as a guide for the adoption of measures for explosion prevention. Explosions in bituminous-coal mines of the United States during the 10 years ended December 31, 1932, ranked third in the causes of fatal accidents and constituted 16.1 percent of all fatal accidents in bituminous mines. Kentucky now ranks fourth in coal output in the coal-producing States of this country; a study of the coal-mine explosions in this state will be of definite interest locally among coal-mining people, as well as to those in the coal-mining industry who are concerned in preventing coal-mine explosions. This circular reviews gas and dust explosions in Kentucky coal mines to show their hazards, to point out the influence of certain factors in causing explosions, and to indicate the effectiveness of preventive measures.

Jan 1, 1934

By Oliver C. Ralston

The Nonmetals Division studies problems relating to the use of minerals, many of which are important to national defence for purposes other than the extraction of metals. In fact, virtually all of the work of the division has been diverted to investigations pertaining to better use of the Nation&apos;s natural nonmetallic is resources as weapons of defense. The experiment stations of the division are at Norris, Tenn.; Tuscaloosa, Ala.; Seattle, Wash.; and College Park, Md. Studies involving the application of electric power to the nonmetallic minerals are conducted at the Electrotechnical Laboratory at Norris, and investigations on mineral-dressing treatment are conducted mainly at the Southern Experiment Station at Tuscaloosa. The cleaning and preparation of coal are studied at both Tuscaloosa and the Northwest Experiment Station Lit Seattle (other projects relating to utilization of coal are conducted by the Coal Division of the Bureau of Mines). Problems covering the use of minerals and fundamental problems as to their properties are studied at College Park.

Jan 1, 1941

By Oliver C. Ralston

The Nonmetals Division studies problems relating to the use of minerals, many of which are important to national defense, for purposes other than the: extraction of metals. In fact, virtually all of the work of the division has been diverted to investigations pertaining to better use of the Nation&apos;s natural nonmetallics is resources as weapons of defense. The experiment stations of the division are at Norris, Tenn.; Tuscaloosa, Ala.; Seattle, Wash.; and College Park, Md. Studies involving the application of electric power to the nonmetallic minerals are conducted at the Electrotechnical Laboratory at Norris, and investigations on mineral-dressing treatment are conducted mainly at the Southern Experiment Station at Tuscaloosa. The cleaning and preparation of coal are studied at both Tuscaloosa and the Northwest Experiment Station Lit Seattle (other projects relating to utilization of coal are conducted by the Coal Division of they Bureau of Mines). Problems covering the use of minerals and fundamental problems as to their properties are studied at College Park.

Jan 1, 1941

By D. J. MacDonald

This U.S. Bureau of Mines report reviews published information on synthetic berlinite (AlP04) and suggests experimental conditions requisite for its production. Berlinite is a piezoelectric material with potential use as a substitute for quartz in the crystal oscillators, which are components of electronic and electroacoustic equipment. Information gathered here (mostly from published sources) includes historical background, physical properties, end-use applications, criteria of quality, and physio-chemical factors involved in berlinite crystal growth. It is concluded that growing large high-quality berlinite crystal would require high-purity starting materials in an autoclave equipped with a noncorrodible liner and operated with temperature control of ±O.OO5 ac over a range of 250 to 350 ac.

Jan 1, 1995

By Nik Sokol, Eric Sekulski, Leo Weiman-Benitez, Jon Hurt, Shrinidhi Vijayakumar, Phaidra Campbell

The Silicon Valley Clean Water (SVCW) Gravity Pipeline (GP) is the first Progressive Design Build (PDB) tunnel completed in North America. As part of the Regional Environmental Sewer Conveyance Upgrade (RESCU) Program, the tunnel is a key component to replacing and rehabilitating components of the existing conveyance system in San Mateo County, California. The GP consists of a large diameter Fiberglass Reinforced Polymer Mortar (FRPM) pipe installed inside a 4.1 m (13.5 ft) inside diameter, 5.3 km (3.3 mile) long precast concrete segmentally lined tunnel. The tunnel was constructed using a 4.6 m (15.2 ft) diameter Earth Pressure Balance (EPB) Tunnel Boring Machine (TBM) through heterogenous silts, clays and sands. Construction included two separate TBMlaunches from a centrally located access shaft, and a tunnel alignment below but in close proximity to very soft Young Bay Mud. Settlement criteria and mitigation strategies focused on protection of an existing 1.42 m (56 inch) diameter force main and adjoining structures along the alignment. This paper discusses the results of the theoretical settlement analysis versus the actual observed ground movements, while also presenting mitigation measures and adjustments made during tunneling to reduce the risks of adverse settlement.

Jun 13, 2023

By J. E. Chilton

Interim performance specifications are presented for carbon monoxide, methane, and air velocity transducers used in the Bureau of Mines intrinsically safe mine monitoring system. These specifications give quantitative values or qualitative descriptions of the transducers, including environmental parameters and monitoring system measurement and maintenance requirements as recommended by the Bureau of Mines. Commercially available transducer modules and prototype modules are listed together with selected characteristics.

Jan 1, 1983

By Arnold M. Lansche

[Selenium and tellurium are rare elements in the earth&apos;s crust. Their scarcity and primary dependence of supply on copper and lead output are in consonance with the relatively small quantities consumed at 1964 level. Production depending on output of copper and lead creates a supply situation- which would appear to militate against development of large-scale usage of these elements. However, supplies have adequately met. demand in the past decade and can be increased substantially if warranted by new uses for either selenium or tellurium Ores of copper and lead re the principal sources of selenium and tellurium. Byproducts from the smelting and refining of copper and lead concentrates are incorporated in refinery anode slimes from which selenium and tellurium metal are recovered.]

Jan 1, 1967