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By R. L. Virta

Four companies ? H.C. Spinks Clay Co., Inc., Imerys, Old Hickory Clay Co., and Unimin Corp. ? mined ball clay in four states in 2013. On the basis of preliminary data, production was 1 Mt (1.1 million st) with an estimated value of $47 million. Production increased by 3 percent in tonnage from 973 kt (1.1 million st) with a value of $45.1 million in 2012. Tennessee was the leading producer accounting for 64 percent of domestic production, followed by Texas, Mississippi and Kentucky. About 67 percent of total ball clay production was airfloat, 22 percent was crude or shredded and 11 percent was water-slurried.

By O'Halloran. Gerard F.

"ECSTALL MINING has installed in their plants the most modern equipment in the mining industry. At the minesite, digital blocked frequency controls are used to monitor all crushers, conveyors, ventilation equipment and pumps from underground. Distant pumping stations are monitored and controlled by radio. Modern friction skip and cage hoisting systems have been installed with static power supply designed for automatic operation. Rotary-type compressors of recent design are in service in place of the conventional reciprocating-type units. At the concentrator, the 800- and 1500-hp synchronous motors driving the grinding mills have static field excitation and pneumatic clutches, still meeting modern-day concepts, having been• installed in 1966. The maintenance work load has increased annually for the past eight years. The modern plant, with all the present-day sophistication, must have a welltrained and well-organized force of skilled workers, and a maintenance system which will supply realistic facts and guidelines. This presentation will review the relative location of plants, utilities, maintenance and services, plant maintenance control and mechanical control. It is the hope that enough information will be presented to weigh the size of the job and how the resources are utilized for controlled maintenance."

Jan 1, 1974

By P. R. Bradley

This paper is one of a series , dealing with mining methods and costs , sponsored and published by the U. S. Bureau of Mines . Papers of this series are written by engineers and executives of mining companies , at the solicitation of the Bureau , and in accordance with an outline prepared by Bureau engineers , for the purpose of securing uniform presentation and conformable data . The property of the Alaska Juneau Gold Mining Co. is situated near the city of Juneau , Alaska , in what is known as the Harris mining district . Wholesale mining operations have been adopted on a large scale and 10,000 to 11,000 tons per day of gold- bearing ore are mined and sent to concentrators near Juneau . In addition to gold , the ore yields 0.6 ounce of silver and 13.0 pounds of lead to each ounce of gold recovered .

Oct 1, 1929

By Jan Zwarcendyk

This study is primarily directed toward providing an understanding of the economic complexities associated with subsidence damage on the surface resulting from underground mining. Some of the pertinent theories on the physical stresses involved are reviewed, and both remedial measures and relevant laws in various countries are discussed. Part I (Chapters 1-3) is an historical overview of various aspects of subsidence problems (theoretical, remedial, and legal) during pre-World War I, between World Wars, and post-World War II, respectively. Part II (Chapters 4-9) presents a comprehensive analysis of the economic aspects of subsidence in relation to the following mining alternatives: (a) carrying out the lowest cost mining method without regard for any surface subsidence, (b) special mining techniques, (c) partial mining, (d) full recovery with stowing, and (e) sterilization or leaving the mineral unmined beneath selected areas. These alternatives are evaluated in terms of their measurable expenses.

Jan 1, 1971

By C. Vipulanandan

With the aging infrastructure, there is a need to maintain and extend the service life of steel structures in general and steel piles in particular. Steel piles support not only vertical loads but also dynamic horizontal loads in onshore and offshore applications. In order to select the appropriate methods to repair corroded steel piles used in onshore and offshore application, corrosion mechanisms were investigated with the rate of corrosion in various environments. The corrosion rate of steel in soil, water and soil-water interface varied from 2 to 500 µm/year. Based on literature review and analyses, the repair methods can be broadly characterized as protective coating, electro-chemical methods, wrapping and encasement and partial replacement of steel. Also, methods to evaluate the repair materials and the repair configuration have been documented.

By Verya Nasri, James Sullivan, Alex Varas

"INTRODUCTION Many major cities in the United States have a combined storm water and sanitary sewer network. Regular rainfall overwhelms the system capacity and results in millions of cubic meters of untreated sewage being dumped into local waterways. One legally mandated solution includes several kilometers of large diameter shallow or deep rock or soil tunnels, a pump station as well as associated collection sewers, diversion structures and drop shafts. In this paper, the basis for design of different system elements including the drop shafts and pump station is explained in detail. Common construction methods used for different type of shafts including tangential vortex and baffle plunge, and also pump station alternatives comprising cavern or various shaft configurations are discussed. DIFFERENT TYPES OF PUMP STATIONS The dewatering pump station serves as the heart of any deep CSO tunnel system and is critical to the goal of reducing CSOs by providing a controlled release of the stored tunnel volume to the wastewater treatment plant. As the major mechanical component of the project, the station will require the greatest attention by operations and maintenance staff. Designing a durable and easily operated pump station requires addressing some major challenges, including the following: • Longevity – equipment, materials of construction, and station environment • Controlling odors • Safety for operators and maintenance personnel • Easy access to equipment • Protection from hydraulic surges Location. Owners face a fundamental decision relative to the location of the pump station, which will affect how these challenges are addressed. The pump station can be built within the tunnel launch shaft or within its own dedicated shaft. This decision is driven by cost and schedule. Use of the tunnel launch shaft may provide owners cost saving opportunities by not having to construct a separate pump station shaft. However, this will likely extend the pump station construction as much as two years until the tunneling has been completed. Furthermore, delays to the tunneling operation would delay the pump station construction work, potentially leading to delay claims. For this reason, it has been more common to utilize a separate pump station shaft on recent CSO tunnel projects (Nasri et al. 2015)."

Jan 1, 2016

By Alvear G. R. F. Flores

It is now 35 years since the organization of the first sulfide smelting conference in 1983. Since then, the smelting base metals industry has experienced several changes driven by the necessity to improve economic, operational and environmental performances and resource efficiency and meet the increasing market demand for metals. In this continuously challenging environment, it is relevant to recognize which are the main challenges that the industry will face in the coming years and critically address our preparedness to respond to them. This analysis have to consider not only the effort required from the fundamental research and technology aspects but also how these pillars interact with the drivers behind the base metals industry. This paper discusses some relevant aspects required to continue developing the base metal industry focusing on copper. Aspects such as the need to supporting the generation of fundamental metallurgical knowledge, acquisition and proper use of data with advanced analytics methods, technological innovation to develop sustainable process flowsheet are discussed with emphasis on efforts conducted by Aurubis.

By H. W. Gillett, A. E. RHOADS

In its study of methods for reducing metal losses in the non- ferrous metal industry, the Bureau of Mines has conducted a long series of experiments on electric brass melting and collected much data on the experiments of others. Reports bearing on this work that have already been published by the Bureau of Mines are Bulletin 73, "Brass-furnace practice in the United States," and Bulletin 77, "The electric furnace in metallurgical work." A comprehensive report describing the design and operation of all types of electric brass furnaces and showing their performance in experimental tests on a commercial scale is in course of preparation. However, commercial tests of several new and promising types of furnaces are still under way, the results of which should be included in any general discussion of the subject. For this reason it has seemed desirable to issue a preliminary bulletin giving the data on a type of furnace developed in one stage of the bureau's work.

Jan 1, 1918

By W. L. Dare

This information circular is one of a series the Bureau of Mines plans to publish describing the methods and costs of mining uranium on the Colorado Plateau. The Big Buck mine is one of the larger underground uranium-vanadium ore mines on the plateau. The mine is about 39 miles southeast of Moab in the Big Indian mining district, San Juan County, Utah. The Big Buck claims were located late in 1947, when uranium mineralization was discovered in the Cutler formation at its outcrop along the escarpment that forms the west side of Big Indian Wash. Charles A. Steen made the first major discovery of uranium ore in the Chinle formation in the Big Indian mining district on July 6, 1952, when 14 feet of high-grade uranium ore was encountered in a diamond-drill hole drilled on his Mi Vida claim. The Big Buck ore body now being mined by Standard Uranium Corp. is a southeast extension of Steen's original discovery.

Jan 1, 1956

Although alternating-current (a.-c.) power systems and equipment have been used in coal mining for many years, most mines in the United States are powered mainly by direct current (d.-c.). There are several logical reasons for this, but the use of d.-c, equipment is, in most instances, a direct outgrowth of the original practice of using such power for haulage systems. For traction equipment such as the electric trolley locomotive the d.-c. motor has ideal operating characteristics, and thus it has been widely used for haulage locomotive service. The first efforts at electrification of coal mines started with the haulage system and from there branched out to include the many types of electrically powered mining machinery used in the industry today.

Jan 1, 1960

By J Schrank

Double-stack trains in the United States date back to the early 1980s, starting about the time deregulation of the rail industry occurred. Freight rail became increasingly more competitive to trucking and barge or ship, and led to major investments in railroad infrastructure. Since most railroad tunnels in the United States were constructed between 1880 and 1930, they were not built tall enough to accommodate modern double-stack intermodal railcars. Therefore, as double-stack trains became the norm, existing tunnels became bottlenecks, and railroads wanted the tunnels made larger without impacting traffic. This need to increase the clearance while not impacting rail traffic launched a very specialised industry: the design and construction of replacement lining systems in existing tunnels.Several large multitunnel railroad clearance improvement projects have been completed in the country in the last decade, and they have all been done under ‘live track’ conditions. Live track conditions consist of work windows, often anywhere from four to 12 hours, that are provided to the contractor to complete the construction work. By the end of each work window, the tunnel must be secured so that the railroad can run trains.In addition to improving the clearance, these projects provided the railroads with an opportunity to improve the general condition of the tunnels, including structural, seepage, drainage and icing conditions. This paper discusses the design considerations, tunnel assessments and construction methods used for these live track railroad tunnel projects. Seepage and drainage improvements that were incorporated into the clearance improvement projects are also discussed.CITATION:Schrank, J, 2014. Live track railroad tunnel repair and clearance improvement in the United States, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 619–628 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By J. R. Patts, J. P. Rider, J. A. Organiscak, A. B. Cecala

"NIOSH recently completed a 15-month study at an underground limestone mine crusher booth which evaluated three research parameters: (1) the effectiveness of a single-filter filtration and pressurization system for improving the air quality inside the operator booth, (2) comparing the effectiveness of ? > 99 and ? > 95 experimental prototype filters in the system, and (3) evaluating the use of three different pressure monitoring devices to determine the performance of the filtration and pressurization system over time. The protection factor was quantified monthly using particle counters in the respirable dust range (0.3–10 µm), and gravimetric dust samples were gathered at the beginning and end of the overall study. Under static conditions and after outlier removal, the single-filter filtration unit installed offered a protection factor between 8 and 216, depending on the filter type and loading condition. The particle counting analysis shows that the ? > 95 filter offers a protection factor greater than 4-times that of the ? > 99 filter when evaluated over 60 minutes. The booth pressure monitors provided data that proved to be a valid indicator of system performance over time. INTRODUCTION Designed and installed correctly, enclosed cabs, operator booths and control rooms offer mine workers protection from physical hazards, such as flying rock, debris, and noise, as well as a more comfortable environment in regards to temperature and humidity [1]. But while it may be easier to quantify whether the A/C unit is working (measuring the temperature) or observe whether the cab offers protection from flying debris, it can be somewhat more difficult to quantify its performance in reducing respirable dust hazards. For over 15 years, NIOSH has been conducting applied research to improve the air quality inside of enclosed cabs of mobile equipment [2-5]. This work has led to the identification and mathematical modeling of enclosed cab filtration systems [6]. The same principles that govern the performance of filtration systems on mobile equipment are applicable to stationary enclosures such as operator booths and control rooms [1, 7]. Stationary enclosures are similar to enclosed cabs; however, the volume of the work area can be significantly larger. In addition, workers who perform their duties in stationary enclosures tend to stay within the room for a greater percentage of the day, as opposed to workers on mobile equipment who may enter and exit frequently. Structural integrity can be easier to maintain as well, as there is typically less vibration and stress placed on these compartments as compared to mobile equipment. In addition to offering protection from dust and flying debris, enclosures must ensure that workers have a healthy supply of fresh air to avoid elevated levels of CO2, which are known to cause headache and dizziness, impairing cognitive function. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) states that enclosures should have no more than 1,100 ppm of CO2 when outside levels are 400 ppm [8]. In addition, the American Society of Agricultural and Biological Engineering (ASABE) recommends a minimum airflow for enclosed cabs of at least 42.5 m3/hr (25.0 cfm) per person [9] to ensure an acceptable level of CO2."

Jan 1, 2017

By William S. Miska

The study is an economic evaluation of historical, current, and projected refractory uses in the iron and steel industry of the United States. The first part of the report presents a refractories classification and identifies principal trends in the refractories industry; such as, value and volume of shipments, prices of finished refractory products, the number of manufacturers and plants for refractories production and marketing. The main part of the report treats refractory use patterns and technologic developments affecting refractories usage in the iron and steel industry. Changes in use patterns in each furnace type, refractory, and installation costs and the future outlook for refractories in ironrnaking and steelmaking are covered. The last part of the report identifies the principal raw materials used in refractories production and treats trends in refractory raw material consumption. An appendix to the report contains historical time series graphs of shipments of refractory types used primarily by the iron and steel industry and principal refractory raw materials sold or used by producers. An equation of the line of best fit was calculated from the earliest to the latest year in each time series, usually 1950 to 1965; these were extrapolated in order to derive volume estimates for the year 1975.

Jan 1, 1968

By E. D. Gardner

From the standpoint of tonnage and dollar value copper is the most important nonferrous metal mined in North America. The opening of copper mines has had an important bearing on the development and settlement of many sections of the continent. The prosperity of many of the mining States or provinces depends directly upon the copper-mining industry. Normally, about 35,000 men are employed in the copper mines, mills, and smelters of the United States. The United States is the most important producer of copper among the nations; more copper is mined in North America than in any other continent, and for many years the United States alone produced about half of the copper of the world. During the last 10 years increasing production in South America and Africa has reduced the relative importance of North America and the United States.

Jan 1, 1938

Coal research and related activities in 1964 by the Bureau of Mines resulted in many advances in the production, preparation, and utilization of this valuable natural resource. Mining research during the year was marked by work on hydraulic mining, coalbed degasification, mine drainage control, mine sealing, strip-mine rehabilitation, and quenching of mine-refuse fires. Bureau research continued to produce information leading to increased safety in underground mining. Such research included roof and rib control via bolting and bonding, pressure monitoring of coal and mine rock during mining operations, and development of safety devices for detecting conditions leading to roof falls. Other safety work was continued on methane detectors, coal-dust suppression, and mine ventilation equipment and techniques. Mine explosion and explosives research, mine equipment and materials, safety rule modernization, and safety education and training of mine workmen were continued. Coal storage and preparation work in 1964 ranged from freezeproofing of lignite for rail shipment, through washability studies of coals and washing equipment, to research on new ways to remove ash and sulfur from coal. Electric power production, which accounts for a major portion of the market for coal, received further study. Unique power generation systems, including coal-burning gas turbine and megnetohydrodynamic generators, were intensively investigated. Conventional power systems were improved through continuation of work on furnace performance, powerplant stack gas purification, and engineering and boiler water service.

Jan 1, 1965

By Peter J. Nicholson

The methods of reinforcement to be discussed in this paper are all insitu methods, ones that can be used on the soil structure as it exists in the ground, and do not rely on excavation and replacement of the soil. Current practice in the United States, as well as new ideas and methods, will be discussed as they relate to slope stability, retaining walls, and to other uses such as control of mine or cavity related subsidence and to liquefaction control under existing structures. The method is based on the concept of "nailing" or reinforcing the soil in place, and thereby causing a mass of soil to act as a coherent unit. When performed properly, a true gravity structure can be constructed, one that will remain intact under both horizontal and vertical loadings and that will also resist vibrational and seismic loadings.

Jan 1, 1991

By T. Holmes, S. Davison

"A surge bin at Agrium’s Vanscoy potash operations has been plagued with flow, wear, and corrosion issues since being built in 1967. The culprits? The bin’s carbon-steel construction, geometry, and the resultant funnel-flow pattern are the root causes. An investigation and cost analysis indicated that hopper redesign and retrofit would increase production and reduce maintenance and capital costs. The retrofitted bin provides safer, more reliable operation and has a much longer predicted working life. Using this example, the authors describe bulk-solids-flow theory and highlight the importance of customizing bulk-material-handling-system design using appropriate flow properties to improve reliability, safety, and cost effectiveness.RÉSUMÉ Depuis sa construction en 1967, un réservoir intermédiaire de l’exploitation de potasse Vanscoy d’Agrium connaît des problèmes de débit, d’usure et de corrosion. Les responsables ? La construction en acier ordinaire du réservoir, sa géométrie et la structure de débit en résultant au niveau de la carotte en sont les causes fondamentales. Une étude et une analyse des coûts indiquaient que la restructuration et la rénovation de la trémie permettraient d’augmenter la production et de réduire les coûts d’entretien et en capital. Un réservoir rénové permet de renforcer la sécurité ainsi que la fiabilité de l’exploitation, et sa durée d’activité prévue en est augmentée. En se fondant sur cet exemple, les auteurs de l’article décrivent la théorie du débit de matières solides en vrac et insistent sur l’importance de personnaliser la conception du système de manutention des matériaux en vrac à l’aide de propriétés rhéologiques adaptées afin d’améliorer la fiabilité, la sûreté et la rentabilité.INTRODUCTIONIn early 2013, Agrium’s Vanscoy Potash Operations (VPO) engaged Jenike & Johanson Ltd. (J&J) to provide testing, consulting, and structural engineering services related to proposed modifications to the 270 t special standard product surge bin, which Agrium planned to undertake during a two-week shutdown in August 2013. The bin, which had been plagued with flow, wear, and corrosion issues for its entire working life, was essential for the continuous operation of two of VPO’s compaction plants and for efficient dispatching to loadout. The bin often experienced product hang-ups, clumping on the walls, and plugging at the hopper outlet. Two recent unscheduled mill shutdowns had been partially attributed to flow issues in the bin due to clumping and product plugging up at the screws. These problems increased maintenance costs, limited production capacity, and degraded product quality. Holes and paper-thin sections in the bin walls discovered during a 2013 inspection revealed the potential for major hot material leaks or even structural failure. Either issue would stop plant operations until the bin could be repaired or bypassed. Clearly, the bin cone had reached the end of its life and required replacement."

Jan 1, 2018

Coal - Surface Mining Coal Preparation Coal Utilization Research and Development Health and Safety

Jan 3, 1976

By William L. Husk

Stockpiles have always been a necessary part of coal mining except, perhaps, when a person was mining only for the needs of his family from a seam on his home place or coal mined for the use of a small hamlet and carried to each man's house as it was mined. Then it may have been stockpiled at each man's place for several days or on the village common. Mining with this limited production required waste stockpiling. Stockpiling of the products of coal mining, both coal and waste material, has always been a necessity. Very little coal has ever been moved directly or immediately from the working face to the point of consumption and burned. It has always been expedient to stockpile the coal some- where and store the waste.

Jan 1, 1981

By E. C. Keeley

Some Safety Measures at Ontario Mines The following safety precautions have of late been taken by several of the Ontario mines: installation of water crossovers; washing clown of faces to show-up missed holes; insistence on gloves being worn as a protection to men's hands; wearing of safety boots and hats by underground men; and wearing of goggles by all men using hammers, starting holes, etc. In the summer of 1924 the Mclntyre mine began experimenting with means of removing powder smoke from headings by installing fans and pipe-lines of various designs, also with different means of introducing water into the air-blast when blowing smoke. By October of that year they had devised a scheme of water connection between the water and the air line, at a distance of about one hundred and fifty feet back from the face, using two valves and a short hose. By this means a limited amount of water could be introduced into the air which blew into the face, resulting in a fine spray of air and water combined. This spray not only helped to eliminate fumes but also introduced fine particles of water into the air, raising it above the dew point, with the result that when these fine particles of water settled they had attached to them fine dust particles, thus eliminating, to a great extent, the injurious dust caused by blasting. The combined air and water is turned on immediately after blasting and allowed to blow continuously for from four to five hours, until the muckers come on shift.

Jan 1, 1931