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By E. G. King

The literature contains little thermodynamic information regarding inter-oxidic compounds of the ferroalloy elements and, as a result, thermodynamic considerations of extractive and utilization processes involving these elements have been hampered. As part of a Bureau of Mines program to improve this situation, this paper reports the heats of formation of three calcium vanadates and two magnesium vanadates. There were no previous similar data for any of these compounds. The experimental method was hydrochloric acid solution calorimetry, using calorimetric reaction schemes involving the vanadates and their component oxides. The results were expressed as heats of formation from the component oxides and from the elements. Corresponding free energy of formation values were calculated. The data show that the calcium and magnesium vanadates are stable with respect to all possible decompositions in which vanadium remains pentavalent. This conclusion is similar to the one drawn by Koehler6 for three sodium vanadates.

Jan 1, 1962

Successful evaluation and exploitation of resources and reserves relies on the collection of high quality sample data. The quality of the sample data must be maintained through the application of a robust quality assurance and quality control (QAQC) program, including documentation of sampling procedures, training of sampling personnel and the regular monitoring of control samples. However, the application of QAQC programs in the minerals industry is often poor and the purpose misunderstood. It is all too common to have good quality control data collected, but no analysis work carried out until after drilling is completed. In a lengthy drill program, this can lead to problems not being discovered and corrected as they happen. Moreover, rectifying problems afterwards will be costly in terms of time and money, if not impossible. The consequences of poor quality sample data are many and include such effects as over- or underestimation of block grades, misclassification of ore and waste, and lower confidence in the resource/reserve models. The purpose of this paper is to highlight, using case studies, the importance of good QAQC practices to monitor the quality of sampling and laboratory sample preparation and analysis.

Mar 1, 2010

By Robert P. King

In April, 1975 the Colorado School of Mines began monitoring rock mass response associated with a long- wall shield demonstration project near Raton, New Mexico. This project was sponsored by the U. S. Bureau of Mines (DOE) and performed at Kaiser Steel Corporation's York Canyon Mine. Two of the results of the intensive instrumentation effort are the empirical subsidence and horizontal strain models presented herein. These models are based on data gathered during mining three adjacent longwall panels (4N, 5N and 6N). A total of 251 permanent surveying monuments were monitored over the three-panel area. Lines of monuments were oriented along panel centerlines, perpendicular to centerlines and diagonal (45O) to centerlines. Active monuments were monitored twice a week, with less frequent monitoring of stable or slow moving monuments. Primary subsidence monitoring equipment consisted of an AGA Geometer Model 75 and a Wild T-2 Theodolite with -a Wild-Sercel DI-3S distomat.

Jan 1, 1979

By C. E. Wicks, J. E. Tress, F. E. Block

The Bureau of Mines investigated the effects of gamma radiation on materials and chemical reactions to obtain information that could be of value in modern metallurgical practices . Various combinations of metals and their ores and compounds were irradiated in attempts to effect reactions that might be applicable in the extraction and separation of metal values from minerals and The types of reactions studied included complexing of salts , decomposition of hydrated salts , metal chlorination reactions , leaching of ores and minerals , halogen exchange , and various reducing reactions . All irradiations were performed at the Materials Testing Reactor Gamma Facility of the U.S. Atomic Energy Commission at Idaho Falls , Idaho . Spent fuel elements were utilized as the source of the gamma radiation . Some irradiation - induced changes , ranging from mere color change to participation in chemical reactions , were noted . The greatest value of these investigations , however , was the experience acquired , which should be valuable in future explorations of similar nature .

Jan 1, 1964

By M. TAYLOR

AT Grand Saline, some 65 miles east of Dallas, the Morton Salt Co. of Chicago has for some years operated a brine pumping and evaporation plant on a salt dome. They recently drilled trial holes to obtain data on the dome, preparatory to opening, a new mine, with the following results: The dome is in the form of a truncated cone, with an average of 210 ft. of cover. The top of the dome is approximately one mile in diameter, with the town of Grand Saline lying over the northern rim, and the sides slope off at an angle of 50" to 80" from the horizontal. The deepest holes were drilled to 900 ft. without penetrating beyond the salt, and indications are that the salt deposit is several thousand feet thick. As the deposit increases in area with the depth, there is undoubtedly enough salt to supply a mining operation for an almost unlimited period of years.

Jan 1, 1930

By N. Aarthi, G. R. Dodagoudar

The improvement of soft clay deposits using stone columns is a well-established ground improvement technique in the western world. This technique has been well documented and has proper design codes for precise execution in the field. The sand compaction pile (SCP) method is a contemporary technique to stone columns and has limited literature related to the strength characteristics of the loose to medium dense sand deposits treated with SCP. The available studies on the SCPs installed in cohesionless deposits focused on the improvement by indirectly assessing the SPT-N values pre- and post-installation of the SCPs. The widespread implementation of the SCP technique in recent years has increased the need for a more direct evaluation of the improvement. Earlier studies in this regard have revealed that the available design solutions are based on the type of installation equipment, their working efficiency, and accumulated field data. However, it is found that there are no generic design codes for the direct estimation of the ultimate bearing capacity of the SCP improved cohesionless deposits. To meet the design requirement for the SCP treated ground, a series of experimental and numerical investigations are performed in the present study to arrive at a direct framework in the form of design charts based on the pressure-settlement response of the treated ground. The developed design charts give the ultimate bearing capacity (UBC) of the treated sand deposit for the known initial relative density (RD) of the deposit, spacing and diameter of the SCPs, size of the footing, and for the specified target unit weight required for the intended application. It is concluded that the design charts will be of preliminary use to the design engineers to directly evaluate the UBC of the SCP improved loose to medium dense cohesionless deposits as part of the SCP method of ground improvement. It is expected to have more field-scale experiments and in-depth analysis before implementing these charts for actual field execution.

Nov 1, 2022

By Drew M. Kurtz, Jeff L. Rai, Sara F. Frailey, Mohammad Ayub Iqbal

"This paper presents the foundation changes made for a five-span bridge over the Lehigh River constructed as a design-build project. During excavation within the cofferdam at Pier 2 for the construction of a spread footing to bear on rock, it proved extremely difficult to control the water entering the excavation as the sheet pile tips were variable due to the bedrock pinnacles and a weathered rock zone above the top of rock allowing water to pass below the sheeting. Water also entered from the bottom of the excavation, possibly due to the presence of solution openings within the dolomite bedrock. After repeated failures to achieve subgrade elevation and maintain a dry excavation, a design change to drilled shafts was made. Additional borings were performed for each of the shaft locations to explore the area underlain by karstic dolomite rock. A seal consisting of tremie concrete with adequate weight was placed to counter the differential head of water and the three drilled shafts (with minimum 25 feet [7.62 meter] rock sockets) were installed. A detailed construction sequence was followed and advanced quality control testing was performed. The construction of Pier 2 was completed successfully.1. INTRODUCTIONThis paper presents the description of the design change made from spread footing to drilled shafts as a result of site conditions encountered during the excavation for the spread footing for a bridge pier in the Lehigh River in Allentown, Pennsylvania. The bridge is located in an area underlain with dolomite rock, presenting karstic conditions including irregular top of rock and solution openings that provided high hydraulic conductivity below the top of rock. Also, the presence of a zone of weathered rock and pinnacle rock prevented the advancement of sheet piles when constructing the cofferdam. Thus, the difficulties of advancing the excavation to the desired spread footing level resulted in the design change to drilled shafts during construction. Since the project was Design-Build, the design could be changed by a collaborative process through the efforts of the Contractor, its geotechnical and structural engineers, and the State's (owner's) geotechnical and structural engineers and construction management staff."

Jan 1, 2016

By A. B. Cecala

The Bureau of Mines performed a study to determine optimal locations for longwall face methane monitoring equipment. Longwall face ignitions continue to be a concern to the U.S. coal mining industry. Gains in ignition control technology have been somewhat negated by advances in longwall productivity. More reliable, heavy-duty longwall face systems generate higher production rates and increase methane liberation rates. These rates will likely continue to rise in the future as further coal production increases occur. Efforts will continue in the areas of methane drainage, methane containment, and methane dilution. In addition, more effective face methane monitoring is needed. As technology continues toward automated longwall panels, the importance of monitoring for methane at the shearer becomes even more significant. Since the primary face ignition source is the shearer mining machine, the Bureau ran tests to determine the best location to take methane readings on the shearer. This information, in conjunction with data obtained from field studies, provides a knowledge base for selecting optimum face methane monitoring locations.

Jan 1, 1993

By C. Hansen, J. Killey

This paper discusses the replacement of AEROFLOAT ® 1 25 promoter by AERO ® 5688 promoter at Sonora Mining Corp.'s California Mother Lode concentrator. Flotation concentrate is trucked 120 miles to a leach plant in Nevada, so the reduced mass resulting from higher gold grades and reduced talceous gangue and barren pyrite resulting from this change in promoters has brought about a major decrease in shipping costs. Preliminary laboratory testing indicated that free milling gold and controlled amounts of pyrite could be floated using Aero 5688 promoter with reduced dosages of Aero 350 xanthate.2 Extensive plant trials confirmed that the new reagent suite could indeed maintain gold recoveries while reducing total mass. Improved froth characteristics also improved operating flexibility in treating various ore types, and overall reagent costs have been reduced.

Jan 1, 1991

By John C. Machisak

The National Safety Competition is sponsored and conducted annually by the Bureau of Mines, U. S. Department of the Interior, to stimulate greater interest in safety in the mineral-extractive industries and to encourage the development of more effective accident-prevention programs. Since its beginning in 1925, thirty-four safety contests have been conducted. This publication reports results of the 11 annual contests for the period 1948-1958, inclusive. Mineral operations awarded the "Sentinels of Safety" trophy for the best safety record in their competitive group as well as those ranking second, third, fourth, and fifth are listed along with a summary of their achievements in preventing disabling injuries. In addition, this publication contains statistical information reflecting the disabling work-injury experience of all other mines and quarries enrolled in the annual contests. The injury statistics of these operations are arranged in the six groups of the competition and through 1955 are the only data on injury-severity at noncoal mineral operations published by the Bureau of Hines. Recognition of the National Safety Competition in promoting safety has increased steadily during its 34 years. The number of plants participating in these annual competitions increased from 210 in 1925, its first year, to a record of 675 in 1958. The expanding scope of the National Safety Competition indicates that more mines and quarries in the United States are enrolling 90 all available means to promote safety on the job will be used. Safety contests like this are generally recognized, in the field of safety promotion, as an effective way to arouse and hold the interest of employees and officials in accident-prevention programs. They tend to forge individual precautionary acts into group action centered on a common objective, such as winning the ?Sentinels of Safety? trophy.

Jan 1, 1960

By Paul T. Fitzgerald

Risk financing solutions are emerging to fully address environmental liabilities for mining operations. Supported by specialized insurance and alternative risk transfer (ART) products, mine owners can fund, cap and guarantee the environmental liabilities and closure obligations of a mine within a financial structure that will be acceptable to regulators. An environmental risk financing program will permit an owner to transfer the liabilities and indeed the ownership of a site to a third party that has the ability and resources to responsibly execute the closure plan. A properly structured program will be financially viable for the owner and will also respond to community and environmental opposition concerns about sustainable development and the environmental legacies associated with mining activities.

Apr 1, 2005

By B Newcombe

From many years practical industrial experience the author has drawn together a list of the key points to consider when embarking on a large-scale geometallurgical project. Fundamental aspects which must be considered include (but are not limited to):understanding the variability of the orebody both laterally and with depth;comminution properties and variability;flotation properties, requirements and variability – differing ore zones may have substantially different requirements for optimal performance;the role of texture – the consequences of both grain size and distribution and how the circuit will handle these;realistic expectation in terms of the financial requirements and time frame results are required within; andintegration of, and communication between key personnel within the various departments of the site (mining, geology and processing) is a fundamental aspect of any geometallurgically based processing system. An example of a highly complex nickel sulfide ore will be used as the basis of discussion.

Sep 5, 2011

By Andrew W. Jenike

The first significant studies of problems related to the handling and storage of bulk solids were reported at the end of the nineteenth century. Early work originated from the necessity to store large quantities of grain and was concerned mainly with pressures affecting the structural design of silos and bins. The Janssen formula (about 1898) and the work of Ketchum [1] form the highlights of that period. In more recent years, progress in mechanization, increasing plant capacities, and rising costs of labor have focused the attention of engineers on the problem of gravity flow of bulk solids. A great deal of work has been done with models, and flow patterns obtained in small scale bins have been described in several publications, for example [2, 3]. An attempt to develop a theory of flow of bulk solids was reported in 1954 [4, 5, 61 and presented to the in a paper [7] in the same year. AIME recommended the continuation of this work and, as a result, Engineering Foundation granted a sum of money to set up a Bulk Solids Flow Laboratory. Two and a half years ago the project gained the support of the University of Utah and a laboratory was set up on the campus of the University. This project is now in progress, it has received the support of the American Iron and Steel Institute and of Kaiser Engineers, Division of Henry J. Kaiser Company. The results obtained to date are summarized in this report.

Jan 1, 1959

By Jack R. Miller

This session has been organized to suggest to you that the development of direct reduction is important to the iron ore mining and coal mining industries. The papers presented this morning will include a discussion of the costs of making direct reduced iron (DRI), the iron ore and coal supplies needed to produce DRI, the financing of direct reduction (DR) projects and, probably most important, the impact of the DR development on the iron ore and coal industries. For starters, this opening presentation offers a brief statement about DR practice and DRI, under the title that should surprise no one: "Direct Reduction: What Is It?" There is always the chance? that a brief statement may become long and complicated. But, by mixing some slides borrowed from Hal Lownie with a larger number of photographs accumulated from other sources, I hope to avoid such pitfalls.

Jan 1, 1978

By Scott A. Stebbins

This Bureau of Mines publication presents a method for estimating capital and operating costs associated with the exploration, mining, and processing of placer deposits. To ensure representative cost estimates, operational parameters for placering equipment and basic principles of placer mining techniques are detailed.

Jan 1, 1987

By J. H. Soulé

This information circular is one of a series published by the Federal Bureau of Mines describing methods and costs at various mining operations. The Schwartzwalder uranium mine, situated about 20 miles west of Denver, Colo., is an important source of uranium ore in the Front Range. Production was begun in 1953, and nearly 36,500 tons of ore had been shipped by September 1, 1958. The mine is operated by Denver-Golden Oil & Uranium Co., Denver, Colo. Much interest has been shown in the property since uranium mineralization tit was found by Fred Schwartzwalder in 1949. The Atomic Energy Commission, Federal Geological Survey, Office of Minerals Exploration (formerly Defense Minerals Exploration Administration), and Federal Bureau of Mines have done work in the area, and various private concerns have shown interest in the property.

Jan 1, 1960

By Marco Olper

The Italian company Engitec Impianti has developed a new electrochemical technology for the treatment of Electric Arc Furnace (EAF) flue dust generated in steel mini-mills. This process is based on a new and completely different concept from the Waeltz technology applied at present and allows, due to its modular nature, for an erection on the steel producer's site. Engitec Impianti spent US $700.000 constructing a 500 t/y throughput pilot plant at Pittini Group's Ferriere Nord mini-mill in Osoppo, Italy in order to demonstrate the process capabilities and obtain the data for a commercial plant design. The paper describes the pilot plant performances and the engineering criteria for a commercial unit of 10.000 t/y throughput. The feasibility study demonstrates a pay-back period of 3 - 4 years for the commercial plant.

Jan 1, 1995

By W. J. Martin

At the termination of mining, the quality of ground water in the ore-zone aquifer must be returned to a condition predetermined by the permitting agency. To immobilize the redox-sensitive elements (e.g., uranium, arsenic, selenium, molybdenum), it has been suggested that a reducing agent be circulated through the leached ore zone. We have conducted laboratory experiments to test the ability of sodium sulfide as such a reducing agent. Sodium sulfide lowered the redox potential of the effluent such that insoluble minerals containing the redox-sensitive elements should be stable. The uranium concentration of the solution decreased by more than three orders of magnitude. In column experiments, by the time ten pore volumes of the sulfide solution had flowed through, sulfide minerals were forming. The experimental results indicate that the addition of sodium sulfide should cause the chemical reduction of the leached sediments, thereby producing long-term stability of the ground-water/sediment system.

Jan 1, 1986

By J. -G. Swanson

Dust control in longwall coal mining depends primarily on the prevention of dust at the source and secondarily on the suppression of airborne dust. One of the primary methods for the prevention of dust is the wetting of the coal face prior to extraction, which can be achieved with water spray systems installed on the shield supports. The spray droplets must travel across the airway to the longwall face, where high ventilation air speeds can entrain water droplets and prevent them from reaching the face thus minimizing the dust control at the source. Through an evaluation of spray plume characteristics in a wind tunnel, the droplet size and droplet drift behavior was determined. This drift behavior was examined by evaluating the spray plume concentration drop and the droplet size shift near the nozzle exit at varying air speeds. Based on these evaluations, CFD modeling was applied to simulate the spray behavior for varying geometries. These results led to the selection of appropriate spray nozzles capable of carrying water droplets to the face at higher air speeds, resulting in an adequate wetting of the coal face and reduced dust generation.

Jan 1, 2012

By R. F. Neider, W. R. Bain

"Expanding upon one aspect of a recent paper on ""Fluid Column Roasting at Sherbrooke Metallurgical Co. Ltd.,"" the present paper deals with the operation of the fluid column process to achieve substantial elimination of cadmium and lead during the roasting of pelletized zinc concentrates. Designed to meet the need for additional feed for Matthiessen and Regeler Zinc Company's vertical retort zinc smelter in West Virginia, without recourse to a sintering operation, the plant is capable of simultaneously attaining very low lead and cadmium levels on demand, through operation in the manner described. Fluidizing air admitted via the wind box is supplemented by natural gas admitted via a tuyere bank 15 ins. above the hearth, in quantities adjusted to maintain a reducing atmosphere within the interstices of the bed. In addition, careful attention is paid to bed temperatures, which run from 1,080° to 1,100°C. Under these reducing conditions, 90 per cent of the cadmium and 92 per cent of the lead in the feed are eliminated, the sulphate sulphur content is decreased by 0.5 per cent, sulphide sulphur is held at 0.6 to 0.08 per cent, and the zinc content correspondingly in-creases. The fuel value of the natural gas is recovered as extra steam, which carries a credit. There are some added difficulties with fume accretions, gas conditioning and gas -cleaning, some of which have yet to be overcome."

Jan 1, 1967