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By Charles W. Perry

The options of enhanced oil recovery, coal syncrude, and shale syncrude are compared by approximately equivalent economics. The physical constraints for the major enhanced oil recovery processes are described, followed by new estimates of cost. The range for all three options in terms of light syncrude equivalent are $22 to $40 per barrel in 1980 dollars.

Jan 1, 1982

By Robert H. Peters

Several significant problems associated with employee turnover among underground miners are described in this Bureau of Mines report. Although a vast amount of research has been conducted on turnover among employees in nonmining industries, there has never been an attempt to empirically investigate the causes of turnover among underground miners. This report presents the results of empirical research on employee turnover in other industries and describes and critiques the research methods that have been used to investigate turnover. Using the findings on employee turnover in other industries and known data about miners and the mining industry, a conceptual model of the factors that cause turnover among miners was generated. This model, which is expected to provide a basis for later empirical studies, is presented. Several recommendations for controlling miner turnover are also presented.

Jan 1, 1986

By John Paul Gries

This Bureau of Mines report reviews the mineral industry of the Black Hills area, including Butte, Custer, Fall River, Lawrence, Meade, and Penning- ton Counties, S. Dak.; and Crook, Niobrara, and Weston Counties, Wyo. It includes discussion of geological occurrence, processing, and potential of 27 commodities that have been produced from the nine-county area. The value of mineral production exceeds $70 million annually. Gold and petroleum account for two-thirds of the total, followed by clays, cement, sand and gravel, and rock. The combined mineral industries annually consume 268 million kilowatts of electrical energy, 933 million Mcf of gas, and 2 million barrels of fuel oil. Water consumption is about 10,000 gallons per minute. About 2,700 persons are employed on a year-round or significant part-time basis.

Jan 1, 1974

By Fred D. Wright

This paper describes research at the Bureau of Mines experimental oil-shale mine at Rifle, Colo., to improve blasting techniques and reduce breaking costs. Many of the conclusions are applicable to any mining operation. Experiments Were conducted on many phases of blasting. The effectiveness of various grades of explosives was compared, and several different drill-hole patterns were tried in heading rounds. An experiment was conducted to determine the maximum effective burden for various diameter blast holes. High-speed motion-picture studies were made of blasts, and the time for initial movement of rock after detonation of the explosive was measured. Experiments with millisecond-delay detonators in heading rounds proved that, when used properly, these detonators result in improved fragmentation, economical use of explosive, and compact, easily loaded muck piles.

Jan 1, 1953

Zinc alloy castings continue to account for a very large, world-wide end-use market for zinc. However, an ever expanding multitude of other materials and processes are increasingly providing viable, cost-effective alternatives to designers, many of whom have no particular allegiance to any one industry. In order to meet this challenge, innovation of and for the zinc hot chamber pressure die casting process, in concert with sustained and inventive market development, is clearly required. While 'Quality' is now the watchword, and the goal of zero defects is being rigorously pursued, other important goals which must be addressed include net shape casting, enhanced productivity and increased energy efficiency. The paper gives an overview of several practical, process-orientated, projects designed to help achieve these goals. For example, a project designed to understand and precisely measure dimensional changes of castings with time has provided some of the critical information needed for net shape casting. A second study is looking anew at surface quality in relation to process conditions as an important step toward the goals of zero scrap rate and increased productivity. Developing the correct die casting machine parameters for achieving optimal quality and properties of zinc (ZA) die castings is a further example of research designed to benefit both the die caster and his customer, chiefly the original equipment manufacturer (OEM). A project on die soldering or galvanising in response to varying process parameters is similarly being considered in order to foster increased understanding and avoidance of problems, with a special interest in the use of special coatings. The maintenance or expansion of the future market for zinc die casting alloys also depends on design for functional applications, as an adjunct to their traditional decorative use. The role that alloys with enhanced properties can play, such as ZATEC, a new high creep resistant alloy developed specifically for elevated stress/elevated temperature applications, will be briefly discussed.

Jan 1, 1993

By K. Englehardt

J BERESFORD introduced the subject of the paper which is the use of polymeric slurries to support the sides of diaphragm wall and bored pile excavations during construction. In the opinion of the authors the use of a suitable polymeric fluid offers financial and technical advantages compared with traditional bentonite based slurries. Under quiescent conditions a support slurry must have the following properties. - sufficient viscosity to support the sides of the excavation, to prevent infiltration into soils and to hold loose soil particles in suspension. - when agitated it should thin quickly to assist pumping transfer and cleaning and allow free passage of the grab or drill. - viscosity should be low enough during concreting to facilitate placement but high enough to prevent contamination of the concrete.

Jan 1, 1991

By Larry J. Nicks

The Bureau of Mines is investigating the catalytic activity of rare-earth compounds to develop a catalyst for the cathode reaction of a hydrogen-oxygen fuel cell. This report presents the results of studies of the catalytic activities of lanthanide oxides for the oxidation of hydrogen at 150° to 250° C. Preliminary activity tests were made with approximately stoichiometric mixtures of hydrogen and oxygen diluted with helium. A series of tests was also run under oxygen-rich conditions in which specific rate constants and activation energies were determined. Variations in rate constants up to 2,000 times were observed for the various lanthanide oxides. The three most active catalysts were oxides of Ce, Pr, and Eu, having specific activities of 6.93 X 10-7, 4.88 X 10-7, and 4.06 X 10-7 moles H2.sec-1.m-2, respectively, at 200° C.

Jan 1, 1973

By H. W. Fleming, R. R. Brooks

The Clearwater Deposit, a small occurrence of massive-sulphide mineralization enclosed in an envelope of disseminated-sulphide mineralization, was discovered as a result of an aeroelectromagnetic survey in New Brunswick in 1955. Subsequently, additional flights were made over the deposit and various ground follow-up methods were employed to ascertain the nature of their response. All methods proved to be capable of indicating the occurrence with varying degrees of precision. This paper is a presentation and a discussion of the magnetic and electromagnetic data, both airborne and ground, and the self-potential data obtained over this deposit. The attention of Canadian mining exploration companies was initially focussed on New Brunswick by the discovery, in 1953, of the Brunswick ore body. Ground electromagnetic surveys were of considerable assistance in locating and developing this deposit. In the following year, 1954, the Heath Steele base-metal deposits were discovered by employing an airborne electromagnetic device and ground electromagnetic surveys to follow-up the airborne indications. These discoveries demonstrated clearly that both airborne and ground electromagnetic techniques were applicable for locating the near-surface deposits of massive sulphides present in this region. Airborne electromagnetic equipment became available on a contract basis through Aeromagnetic Surveys Limited early in 1955 and was used extensively thereafter throughout a large portion of northern New Brunswick. It was as a result of one of these surveys with Aeromagnetic Surveys Limited equipment in the summer of 1955 that the Clearwater Deposit was detected. The airborne anomaly was located on the ground by means of an electromagnetic survey using a Swedish Slingram unit. During 1956, the region was investigated more thoroughly- in the hope that other sulphide bodies might be located. Airborne electromagnetic coverage was extended and the Clearwater Deposit itself was used as a testing ground for the various methods and types of equipment currently in use in New Brunswick. In this paper com prative data are presented for the airborne magnetic, airborne electromagnetic, ground magnetic and ground electromagnetic surveys over this deposit. The ground electromagnetic instruments used were the McPhar vertical-loop unit and the Slingram and Boliden horizontal-loop units. Self-potential surveys were carried out with a McPhar unit. From the geophysical point of view, all ground electrical methods employed indicated the presence and the extent of the massive-sulphide mineralization with a good degree of accuracy. The horizontal-loop methods however, defined the contacts more precisely as is to be expected when dealing with a flatly-dipping

Jan 1, 1961

Support design in jointed or blocky rock masses is often approached by the use of either 'rules of thumb', rock mass classification systems such as the Q-system (Barton, Lien and Lunde, 1974) or RMR (Bieniawski, 1973) or conventional wedge analysis. Generally, this requires that a number of key simplifying assumptions are made and the support system is designed to cater for either a mean, most likely, or worst case scenario depending on the risk tolerance. The design block size is often a major uncertainty and often a worst case block size based on excavation span is used. Thompson and Windsor (2007) state that it is inappropriate to base support designs on the excavation size as these size blocks rarely occur if discontinuity trace lengths are considered. Probabilistic keyblock methods can be used to determine the most likely design block sizes. A methodology is presented whereby JBlock software (Estherhuizen, 1996) is used to estimate potential block sizes as part of the support design process. Using information such as the spacing, orientation and length of discontinuities, it is possible to simulate blocks in the walls of an excavation (Esterhuizen and Streuders, 1998). Keyblock analysis methods (Goodman and Shi, 1985) are used to evaluate whether blocks are removable and whether the chosen support will be sufficient to ensure stability. Data from two mines is used to demonstrate how probabilistic keyblock analyses can be used in support design. Discontinuity data was used to generate 10 000 removable blocks and the design block size statistics were determined. For one mine this information was used to scale blocks in a conventional. Unwedge analysis whilst for the other mine, the point estimate method (Harr, 1987) was applied. The choice of appropriate design acceptance criteria in terms of factor of safety and probability of failure is also considered.

Nov 25, 2010

By B. DANIEL MARJAVAARA, I. A. SOFIA LARSSON, ANNA-LENA LJUNG

One way to upgrade iron ore is to process it into pellets. The pelletizing process is multifaceted, involving complex fluid dynamics with highly turbulent, high-temperature flow in intricate geometries. This makes it hard to perform measurements during operation, so a useful tool for better process understanding is computational fluid dynamics (CFD), where the challenge is to perform efficient and trustful simulations of complicated problems. A validated simulation model can be valuable for increased process control and development. In this paper, the flow field and coal combustion process in a pilot-scale iron-ore pelletizing kiln is simulated using a CFD model. The objective of this work is to apply a coal combustion model to enable an investigation of thermal effects from the flame on the surrounding flow field.

By W. D. Presley, T. R. Harrell

This paper will be a case history of the shaft and tunnel concrete lining techniques used at the Rocky Mountain Pumped Storage Project located in northwest Georgia. Emphasis will be placed on the shaft lining techniques with only a brief description of the tunnel concrete lining techniques. The 10.67 meter (35 foot) diameter shaft and tunnel concrete linings are 0.61 meter (2 foot) nominal thickness with a single row of reinforcing bars. The tunnel was placed in 18.29 meter (60 foot) lengths with bulkheaded end sections. The 172.72 meter (566.68 foot) vertical shaft was placed in 3.05 meter (10 foot) high sections using jump forming techniques.

Jan 1, 1985

By William F. Ryan, Paul T. Gribbon

With the rise in construction claims in public works contracting over the years, the use of Dispute Review Boards (DRB’s) in underground construction contracts has become quite common. However, in order for the DRB process to be an effective tool, there must be complete trust and confidence in the Board members and their adopted procedures by both the owner and contractor. This can be difficult in an industry where Board members and contractors may be well known to each other, while an owner maybe involved in a large complex underground project only occasionally. Using case histories, this paper will discuss some recent experiences with the DRB process from an owner’s perspective.

Jan 1, 2003

By Jan W. Oberholzer, Patrick Linzer

The globally increasing environmental awareness which has manifested itself in the past few years also encompasses problems associated with mine closures. A crucial requirement for the effective planning, management, monitoring and control of mine closures is an information system which allows the qualitative and quantitative evaluation of proposed closure strategies, not only in terms of their local influences, but also of their potential effects on areas farther a field. This paper describes some of the closure associated problems and the establishment of such an information system from existing facilities, all of which are readily available. No modifications to these facilities are necessary, which enables rapid and cost-effective implementation of the system.

Jan 1, 1996

Minerals are vital to any industrialized civilization. Annually, the United States uses more than 4 billion tons of new mineral materials, or about 40,000 pounds per person-about half being mineral fuels and the other half metals and nonmetallics. Stable and economic domestic mining, mineral, metal, and mineral reclamation industries are essential to the economy. The value of United States energy and processed materials of mineral origin exceeds $200 billion annually. Although a number of minerals are imported, especially some designated as "strategic and critical," most U.S. mineral supplies are derived from the domestic mines and processing facilities that you will be seeing, reading about, and visiting as you use this visitor guide. We hope you enjoy your experiences. This pamphlet, a guide to mining and mineral operations that may be observed or visited and some other points of interest relating to minerals, is intended to aid tourists and students who are interested in mining. Some may wish to study our Nation's romantic past; others may plan to enter the minerals industry as a career; still others may have a primary interest in conservation practices. The pamphlet is also intended to aid State and local officials, Chambers of Commerce, and mining firms in answering some of the many questions of tourists and students.

Jan 1, 1977

By George H. Popper

The Bureau of Mines has evaluated the extent of phosphate resources available for recovery by the experimental borehole mining method in the Southeastern Coastal Plain of the United States- Phosphate re- sources at overburden depths greater than 30 m are as a rule currently unsuitable for recovery through conventional mining methods because of economic, environmental, or technical considerations. In the identified deposit areas, borehole mining operations are projected to yield a more favorable rate of return and to be environmentally more desirable than conventional surface mining. Borehole mining resource estimates presented in this study are preliminary and designed to serve as a basis for future resource evaluations, as the current data base is relatively sparse and incomplete. The resulting resources have, therefore, been classified as hypothetical and speculative and are subject to up- dating as additional exploratory data become available. Hypothetical and speculative resources amenable to borehole mining are estimated to total about 385 billion metric tons (rat) of phosphate matrix with a minimum in situ grade of 5 pct P205. With projected borehole mining capabilities and current conventional beneficiation procedures, this resource would make available approximately 64 billion mt of phosphate rock product at an estimated grade of 30 pct P205.

Jan 1, 1985

By Laxman S. Sundae

The Bureau of Mines designed, fabricated, and is using an in-seam tester (1ST) for in situ determination of coal cutting forces. This re-port describes the results of field tests conducted in the Pocahontas No. 3 and Upper Freeport seams to obtain peak and mean cutting forces during coal cutting with several bit geometries, including radial and point attack bits currently used on drum-type machines. Comparisons were also made between new and worn bits, and using data obtained from a Bureau-modified chisel bit. The test results show that longwall plough cutting (horizontal cuts) in bony coal bands (shale) requires >3 times the cutting force for the same cuts in a vertical direction. When no bony coal is present, the cutting forces required to make horizontal and vertical cuts are equal. Worn bits require 4 to 5 times more cutting and normal force than new or undamaged bits. Normal force increased drastically for the worn chisel bit. Peak force encountered in making independent cuts was found to be ~3 times higher than that required to make interactive cuts using a spacing-to-depth-of-cut ratio of 2. Both rake and clearance angles were found to have a significant effect on normal and cutting force.

Jan 1, 1986

By Tilyard P. A

Pasminco has tested a Valmet ES1 ceramic disc vacuum filter at its Broken Hill concentrators. On lead and, particularly, zinc concentrates at the ZC Mine the filter performed well but on North Mine lead concentrate problems were experienced with deposition on the disc, which resisted both ultrasonic and acid cleaning. A preliminary financial analysis showed that the application of the filter at the ZC concentrator was worth pursuing. Accordingly an ES30 machine has been hired for plant evaluation.

Jan 1, 1989

By Aldo L. Furno

Sufficient quantities of combustible vapors are released by some sulfurs to produce flammable atmospheres under prolonged storage. Hydrogen sulfide and carbon disulfide appear to be the principal flammable constituents in the vapor space above molten sulfur. If sufficient carbon disulfide is present, ignition of the vapor-air mixtures can occur spontaneously on contact with the heated surfaces found within storage tanks.

Jan 1, 1963

By J. J. Jakosky, D. H. Zellers

"IntroductionThis paper is the seventh of a series describing an investigation being conducted by the Bureau of Mines on underground communication. A review of past work and results obtained has been published. The present paper deals with a study of line-radio or wired-wireless methods of communication, herein electrical energy is transmitted by metallic conductors.The use of line-radio over metallic conductors has been practiced for a number of years, and at present is being used on a large scale in long-distance carrier-current telephone and telegraph. The early work of the U. S. Army Signal Corps and the Bureau of Standards in using ordinary radio transmitting and receiving apparatus for communication over metallic conductors was been descried. Later publications describe commercial applications, and an excellent treatise and resume is given by E. Colpitts and C. B. Blackwell.Scope of ReportThis report contains (1) a discussion of the chief factors affecting carrier-current transmission, with particular reference in application to underground communication for mines; (2) a description of typical underground circuits used for power and lighting; and (3) description of apparatus used and results obtained in line-radio experiments in coal mines near Pittsburgh, with circuit diagrams, and conclusions as to power requirements and limitations for mine use."

Apr 1, 1925

By Michael Quadagno

Hudson River Pier 86, home of the historic USS Intrepid Aircraft Carrier and the Intrepid Sea-Air-Space Museum, is currently undergoing a $30M reconstruction. This project involves the demolition of the old timber pile supported pier and construction of a new 150 ft wide by 782 ft long concrete pier, built over the footprint of the old piles. The new pier consists of steel pipe piles, precast concrete pile caps, and a composite deck, made up of precast, prestressed concrete planks and cast-in-place concrete topping. This paper focuses on both the structural design and construction of the new pier, with emphasis on the pile foundation. Pier 86 is unique in that it is required to resist the extremely high lateral loads imposed on it by the permanently moored 898 ft long aircraft carrier during severe storms. A total of 360 steel pipe piles support the new pier. These piles, which are 24 in. in diameter and range in length from 58 ft to 175 ft, were driven down to bedrock. The piles, each having 200 ton allowable capacities, work together to resist the significantly large lateral loads exerted on the pier by the ship. The installation of the piles was unique in that all the piles, including the ?super-longs?, were fabricated to-length offsite, delivered to the site via truck and barge, and installed in one piece, eliminating the need for field splicing. The Pier 86 reconstruction will be completed within an extremely aggressive 18 month schedule, from January 2007 through June 2008. The refurbished aircraft carrier Intrepid will return home in September 2008, and the grand re-opening of the pier will be on Veteran?s Day 2008. This paper provides a case history for owners, government agencies, engineers, and construction professionals that will be faced with the challenges of designing and building new piers.

Jan 1, 2008