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By Setareh Afrouz, Emily Sarver, Cigdem Keles

The resurgence of severe lung disease among US coal miners since the mid-1990s has led to efforts to better characterize and monitor respirable dust exposures, particularly focusing on mineral constituents from rock strata surrounding the coal. A rapid analysis method for silica (quartz) mass using direct-on-filter Fourier transform infrared (FTIR) spectroscopy has been developed, which can also estimate kaolinite, a primary silicate mineral in many coal mines.

Feb 24, 2022

The 1965 Lignite Symposium, the Louth in a series and the third sponsored by the University of North Dakota and the Bureau of Mines, was held at Bismarck, N. Dak., on April 29-30, 1963. These symposia provide a forum for those interested in the technology and utilization of solid fuels, especially lignitic coals. As part of the meeting, a 200-mile field trip was taken including; inspection of (1) the 200-megawatt, pulverized lignit-fired Leland Olds plant of Basin Electric Power Cooperative, under construction near Stanton, N. Dak.; (2) the site of the Glunharold mine of the Truax-Traer Coal Co., Division of Consolidation Coal Co., where a wheel excavator was being assembled; (3) the operating Beulah mine of Knife River Coal Mining Co., subsidiary of Montana-Dakota Utilities Co., near Beulah, N. Dak.; and (4) the 400-megawatt, hydroelectric Garrison Dam powerplant, near Garrison, N. Dak.

Jan 1, 1966

By K. O. Bennington

The thermodynamic properties of hedenbergite, of composition [(Ca0,9516) (Mg0,0583Fe2+0.7134 Fe3+0.0934 Mn0,1366) (Si206)], were experimentally determined at the Bureau of Mines. The standard enthalpy of formation determined by hydrofluoric acid solution calorimetry is AHf298 = -680.96±0.855 kcal/mol. The standard enthalpy of formation from the oxides is AR-96 = -24.55±0.485 kcal/mol. Low-temperature heat capacities were determined by adiabatic calorimetry from 12.3 to 300.1 K. The derived standard entropy is S-98 - 41.218±0.148 cal/mol-K. High-temperature heat capacities were measured with a differential scanning calorim¬eter from 397 to 1,147 K. These experimentally determined data were combined with data from the literature to calculate the Gibbs energies of formation and equilibrium constants of formation over the temperature range of measurements. Standard enthalpies of formation are given as a function of temperature. The standard Gibbs energy of formation at 298.15 K is AGf298 = -641.90±0.86 kcal/mol.

Jan 1, 1984

By R F. G Phelps, C J. S Sangster, G S. C

Narrow vein metalliferous mining in the UK has a long history, but there are only two small gold operations at present (Clogau and Gwynfynydd). Four further gold properties are at various stages of evaluation (Calliachar, Cononish, Curraghinalt and Maestryfer). The South Crofty tin mine closed earlier in the year. Narrow veins are exploited underground and are challenging to evaluate because of their geologically variable nature. They are generally less than 3 m wide, discordant, of variable dip (

Jan 1, 1998

By Stacy Loizeaux

The Beirut Hilton Hotel, which was built in 1975, but never occupied, was imploded on Sunday, July 14, 2002 by Controlled Demolition, Inc. (CDI) of Phoenix, Maryland and their client, Optimal Engineering Consulting & Contracting, SARL, (OECC) of Antelias, Lebanon to make room for a new hotel. Twenty-seven years ago, just days before the grand opening, the Hilton Hotel became the site of fighting in Lebanon’s Civil War. Christian and Muslim militiamen fought room to room for control of the building and other nearby hotels. The Hilton, two other major hotels and other high-rise buildings were ravaged by the fighting. The building was one of the three major hotels badly damaged, but not rebuilt, in Lebanon. Located in the City Center, the Hilton stood out in a major redevelopment area which, in recent years, had erased the scars of the 15 year long Civil Wa r.

Jan 1, 2003

By Steve Kral

The coal mining industry in the western United States is seeing the same boom as the rest of the country and the world. Most coal mines in the West are operating flat out as the nation’s appetite for energy continues to grow. And many of the coal mines have either increased their production capacities or are in the process of doing so. However, transportation issues along with environmental restrictions are keeping many mines from expanding even further. Some coal companies held off on further expansion plans until Congress and President Bush could agree on a national energy policy, one that recognizes coal as the nation’s leading source of electricity. In August, Congress passed and the president signed into law such a measure (see Washington Survey, page 7). The legislation includes research funding for clean coal technologies. So western and eastern coal could become even more important in the national energy picture. This is particularly true as supplies of natural gas diminish and the price of oil continues to increase.

Jan 1, 2005

By John C. Machisak

This publication, for the calendar year 1959, contains statistical data on injuries and employment pertinent to metal mines, ore-dressing plants, and primary nonferrous smelters, refineries, and reduction plants. The Bureau of Mines is authorized to request data on injuries and employment in the metal-mining industry, and the information, voluntarily submitted by the operators, contributes immeasurably to the promotion of safety in the metal-mining industry. Every effort has been made to make the annual canvass as complete as possible. The data presented are classified according to the hind of ore mined and includes information on copper, iron, lead-zinc, gold-silver lode, placer, uranium- vanadium, and miscellaneous metals. A breakdown of miscellaneous metals by commodity is shown in tables 17 and 18.

Jan 1, 1963

By John C. Machisak

This publication, for the calendar year 1959, contains statistical data on injuries and employment pertinent to metal mines, ore-dressing plants, and primary nonferrous smelters, refineries, and reduction plants. The Bureau of ,Mines is authorized to request data on injuries and employment in the metal-mining industry, and the information, voluntarily submitted by the operators, contributes immeasurably to the promotion of safety in the metal- mining industry. Every effort has been made to make the annual canvass as complete as possible. The data presented are classified according to the hind of ore mined and includes information on copper, iron, lead-zinc, gold-silver lode, placer, uranium- vanadium, and miscellaneous metals. A breakdown of miscellaneous metals by commodity is shown in tables 17 and 18.

Jan 1, 1963

By George S. Rice

This bulletin traces the growth in the belief in the explosibility of coal dust, summarizes the experiments and mine investigations that have established this belief, and gives the present status of pre- ventive measures. It has been prepared in accordance with the pro- visions of the acts of Congress authorizing investigations relating to the causes of mine explosions, and contains references to and descrip- tions of experiments made at the Federal testing station at Pittsburg, Pa. This station was inaugurated under the United States Geo- logical Survey, and was transferred to the Bureau of Mines on the establishment of the latter on July 1, 1910. Only within comparatively few years has the dry dust of bitumi- nous and lignitic coals been generally recognized as an explosive agent more insidious, threatening, and deadly to the miner than fire damp. Fire damp carries its own flag of warning-the "cap" in the safety lamp-but coal dust, though visible, does not attract attention until present in large quantities. Fire damp is of local occurrence, and except in notable and very exceptional cases is controllable by careful manipulation of ventilating currents. If by mischance a body of fire damp is ignited in a mine, the force of the explosion may be terrific, but the effect is local unless dry coal dust is present, or unless (as it very rarely happens) an explosible mixture of methane gas and air extends through large areas of the mine. In a dry mine dust accu- mulates everywhere, and the blast from the ignition and combustion of bituminous dust may traverse miles of rooms and entries and wreck structures at the entrance to the mine. The comparative potential destructiveness of gas and of bituminous dust is strikingly shown by the history of the Pennsylvania anthracite mines. These mines not infrequently have large inflows of gas, and the resulting mixtures of gas and air have sometimes been ignited, yet no such wide-sweeping explosions have taken place, despite the presence of dry anthracite dust, as have happened in excellently ventilated bituminous mines.

Jan 1, 1911

By Yuanwci Shi

This paper discusses the results of research on the interaction between roof strata and shield supports including the active and passive supporting functions of the shield supports which prevents roof strata separation; pressure distribution on the canopy and under the base plate as measured in the laboratory and underground; comparison between various shield structures regarding their effectiveness on roof and floor control; and determination of optimum support capacity under given geological and mining conditions including hard-tocave roof

Jan 1, 1997

By Jennifer Ward

The primary objective of this paper is to establish how a low cost, high definition (HD) camera can allow for easy sustainable recordings of blasting operations. The subsequent analysis of each video can be utilized to monitor what type of performance was achieved and aids in improving blasting performance.

Jan 1, 2015

By N. Merriam

This report describes Koppelman's work to develop the K-Fuel® Series C Process used to dry and stabilize Powder River Basin coal. It also contains summaries of the results of bench-scale and pilot plant tests conducted to prove the Series C Process. The process is being used by the KFx-Thermo Ecotek partnership for a 500,000 ton per year commercial plant that has been constructed near Gillette, Wyoming. The plant is presently undergoing shakedown.

Feb 24, 1997

By J. Bertisen, G. Davis

Previous analyses of small samples of mining projects have found that feasibility studies tend to well under-estimate the actual capital costs of the project. Our review of 63 mining and smelting projects completed over 4 decades confirms that as-built capital costs are, on average, 25% higher than as estimated at the bankable feasibility study stage. There appears to be little attenuation over time of this bias in capital cost estimation, at first appearing to reflect an absence of learning on the part of the consulting engineer. We instead argue that this persistence of bias is intentional, driven by a scarcity of project financing and the need to inflate the project economics in a bid to secure financing. Around this intentional bias is a considerable amount of scatter. Roughly half of all projects’ as-built capita costs fall outside of the expected ±15% of the feasibility study capital cost estimate, even after allowing for intentional estimation bias. Cost overruns of 100% or more happen in roughly 1 out of 13 projects. The data reveal that a shifted lognormal probability distribution should be used when modeling mining project capital costs in a Monte Carlo analysis.

Jan 1, 2007

By Harry Wolf

The chemistry of the element uranium enables industry to employ either an acid or alkaline carbonate leach solution for most uranium ores. Either method my be used for conventional, in-situ, or heap leaching. Uranium recovery in the leaching process depends both on the solubility of the uranium minerals and, on the access of the leach reagent to them. The uranium leaching rate is proportional to the liberated mineral surface area and the chemical reactions involved in the dissolution step. The dissolution of U(VI) and the oxidation of u(IV) to U(VI) are the basic chemical reactions in the leaching process. The active surface area is a function of the effective porosity and the particle size of the ore (1). Ore pieces, with a high porosity and high permeability, may provide a large active surface area even in coarser fractions. This type of ore might be suitable for heap or in-situ leaching techniques. Nonporous and impervious ores are usually more amenable to conventional milling where the active mineral surface is exposed by grinding the ore down to the liberation size of the mineral.

Jan 1, 1981

By Eugene T. Sheridan

The Bureau of Mines annually canvasses the fuel-briquet and packaged-fuel producers in the United States and publishes economic data on these industries, based upon reports submitted voluntarily by producers. This publication lists all producers that reported commercial production to the Bureau for 1960 and presents data on individual plants. The companies named herein represent virtually all producers of processed minerals fuels. A few small plants may not have been canvassed or failed to respond to the survey because some of the smaller plants operate intermittently and the survey is voluntary. All plants that reported commercial production were included; regardless of size. Specifically excluded were plants that manufactured briquets from wood charcoal. Fuel briquets and packaged fuel are manufactured solid fuels, produced by mixing fine-sized mineral fuels with binding materials and compressing into small individual shapes, Briquets are produced in pillow-shaped and cylindrical form, are 2 to 4 inches long, and weigh 2 to 4 ounces. Packaged fuel consists of 3- or 4-inch cubes; 6 or 8 of which are wrapped together in heavy kraft paper to form a package weighing 10 to 15 pounds, Briquets are durable and may be stored and handled as bulk fuel; packaged fuel breaks easily and must be stored indoors to prevent it from deteriorating. Whereas briquets are consumed in many areas as a general residential fuel, packaged fuel is more of a specialty item, used at times to supplement other fuels. Packaged fuel is burned without re-moving the paper and is referred to as the "white glove" fuel.

Jan 1, 1961

By Elford H. S

Mr. H. W. GEPP said he desired to bring particular attention to this paper. The underlying intention of the Development and Migration Commission when the paper was prepared was to place at the disposal of Australian miners and metallurgists the story of the development of tin metallurgy as it had been advanced in other countries, particularly Great Britain. They had very considerable resources of low-grade tin-bearing metals in the eastern coast of Australia particularly, and they need not anticipate that tin was going to remain at the extremely low price at which they saw it to-day. The Commission felt that it was most desirable to place 'on record, and make easily available, the story of the treatment of comparatively low-grade tin ores in other parts of the world.Arrangements were made that the technical staff at Australia House, in conjunction with Mr. H. S. Elford; should collect this information so that in due course, when Australia awoke to an interest in low-grade deposits, of which there were many throughout Australia, this story would then not,have to be gathered from other areas and other places of the world. The -paper was a contribution which would turn out to be of very great value. He suggested to the younger members that this thorough contribution could be made the subject of study so that they would be ready to assist in the developments which must come. Mr. WM. APLIN said there was one point in connection with the paper upon which he would like to speak. While at Mount Morgan he had occasion to test some highly pyritic tin ore by flotation, with a view to separating the cassiterite from the pyritic mineral.Instead of accomplishing that, it was discovered that it would be possible to eliminate as much as 50% of the total weight of ore in the form of a pyritic flotation concentrate, which would contain...

Jan 1, 1930

By F. Enslin

Heavy metals and sulphates in acid mine drainage (AMD) can beadsorbed onto bentonite clay, leaving clean water and a heavy metal loaded clay precipitate as products. Due to the toxicity of heavy metals, the clay could not be disposed of safely in the past. A method was thus required to remove the heavy metal content from the clay. Acid leaching was proposed to liberate the heavy metals from the loaded clay. Sulphuric, nitric and hydrochloric acid were considered as lixiviants. Loaded clay samples were leached over a range of pH values from 1 to 3.5 to identify an optimum leaching condition. From the results it was found that metals can berecovered from loaded bentonite clay by means of acid leaching and the optimum pH for heavy metal liberation was found to be 2.5, with uranium as an exception, being optimally leached at a pH of 3. This allows for the possibility of selective leaching. Furthermore, X-ray diffraction analyses indicated that the clay structure did not deteriorate significantly during acid leaching, suggesting that the bentonite could be reused. The treatment of AMD with bentonite clay, and subsequent acid leaching of the clay, is a sustainable solution, and current outcomes could possibly lead to industrial implementation of the process during water purifying and metal recovery from waste streams. Keywords: Acid mine drainage, bentonite, heavy metals.

Jan 1, 2010

By R. K. Koch

The vapor pressures of liquid titanium and liquid platinum were studied under the Bureau of Mines program for the determination of thermochemical data on the transition elements. Beating was done in a 2-kw electron-beam furnace with a water-cooled copper crucible to contain the melt. Temperature was measured with a disappearing-filament brightness pyrometer. The vapor pressure data for liquid titanium in the range 2,008° to 2,379° K are represented by the least-squares derived equation [log p (atm) = 6.268 - 22, T] Two series of determinations were made on liquid platinum. Results of the first series are expressed by the least-squares derived equation [log p (atm) = 8.240 - 30,460T] for the range 2,0860 to 2,4200 K. Results of the second series are expressed by the least-squares derived equation [log p (atm) = 7.795 - 29,580 T] in the range 2,045° to 2,442° K. Third-law evaluations of each series gave mean standard heats of sublimation of 112.4 kcal/mole, 133.3 kcal/mole, and 133.8 kcal/mole for titanium first series on platinum, and second series on platinum, respectively. Second-law heats of sublimation and equations for heats, free energies, and entropies of vaporization were obtained from sigma plots of each data set.

Jan 1, 1969

By Yufeng Guo

Mineralogy and physico-chemical characteristics of a nickel hydrometallurgical residue and recovery of iron-bearing minerals by flocculation-magnetic separation were studied. The results show that the nickel residue is super-fine and fraction less than 0.045mm reaches 85.4%. Ferrous minerals are chiefly magnetite and ferruginous glass. Magnetite accounts for 31.7% and exists as free magnetite. Ferruginous glass is of multicomponent amorphous substances with low-iron grade but strong magnetism, and accounts for 39.9% of total iron minerals. Addition of flocculants increases granularity and magnetic force of fine iron-bearing particles and improves iron grade and recovery. The tests with flocculation separation show that a concentrate assaying 56.68% Fe with 81.72% recovery was obtained in a magnetic tube. A concentrate with 56.92% iron grade and 67.96% recovery was obtained by flocculation-magnetic separation with a magnetic cylinder.

Jan 1, 2006

By Steve Stuart

Deep-sea mineral SMS deposits present some of the world’s most challenging conditions for drilling equipment. As robotic seabed drilling services mature so too the ways that clients engage with service providers to maximise their data requirements. This presentation reviews key considerations for planning and executing a successful seabeddrilling program in variable mineralised deposits. Some of the means of collaboration between robotic seabed drilling contractors and those hiring their services are explored; where improved efficiencies and recoveries over the period of a drilling programme could be achieved. Potentially new technology or methodology can be looked at to further improve these approaches.

Sep 1, 2014