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By P. M. Johnson

A design for a laser-powered optical interferometer, using a specimen whose thermal expansion is to be measured as part of the optical system, was conceived and applied in a prototype dilatometer. The object of thin work was the development of an absolute dilatometer capable of use at elevated temperature, particularly above 1,000° C. The prototype has been operated at temperatures exceeding 1,510° C. Results obtained with this device agree within 2.5 percent with the published data for the coefficient of expansion of columbium.

Jan 1, 1968

By G. Andrews

This case study details the process that was used for project planning and permitting for the Greens Creek Mine, located near Juneau Alaska, as seen through the eyes of one of the primary environmental consultants. This case shows how a Company could involve the public and the agencies in the early 1980's and develop a project sensitive to concerns expressed with a high level of environmental protection. Comparisons are made to the current environmental permitting situation. Initial baseline studies performed during the exploration phase provided helpful information for more detailed environmental work in 1980-1981 as planning and permitting formally got underway. Since the mine was in a National Monument and abuts up to a designated wilderness, the Monument Manager administered the project for the lead agency, the USDA Forest Service. Planning and permitting progressed smoothly to a Final Environmental Impact Statement (FEIS) in 1983. Metal prices were depressed when the FEIS was completed and the project permitting proceeded slowly. Ownership changed several times in the mid-1980's. New owners re-evaluated the project and suggested five changes that required a supplemental EA prior to development. The project was fully permitted and started construction in 1988. Operation began in 1989. Today the environmental process in southeast Alaska is now much more complex, detailed, expensive, and time consuming than in the early 1980's. Significant issues discussed that may impede development and operation include overlapping agency jurisdictions, personal agendas of agency staff, conflicts between agencies that impede project progress, changing regulations, and a well organized environmental opposition.

Jan 1, 1993

By Sarkis G. Ampian

Crystalline silica (quartz, cristobalite, and tridyrnite) is regulated by the Mine Safety and Health Administration (MSHA) and Occupational Safety and Health Administration (OSHA) because of its potential for causing debilitating but nonmalignant lung diseases. In 1987, the International Agency for Research Against Cancer (IARC) conducted a review of the health literature and concluded that crystalline silica was a probable human carcinogen. As a result of this finding, OSHA was required to regulate crystalline silica under its Hazard Communication Standard (HCS). The standard requires that all materials handled by OSHA-regulated facilities be labeled according to the requirements of RCS and that workers receive proper training on the handling of the material if the crystalline silica content equals or exceeds 0.1 weight percent (0.1 %). MSHA currently is considering enacting its own RCS. This will be similar to OSHA's RCS. If the standard is enacted, most mineral producers will have to determine the respirable monitor filter and bulk crystalline silica contents of their ores and products so that workers and/or customers will know whether they are in compliance with the 0.1% HCS and/or the OSHA permissible exposure level (PEL) of 50 µg for an 8-hour workday for respirable crystalline silica as determined from monitor samples. Two major concerns with the RCS are the widespread occurrence of crystalline silica in nature and the suitability of current technology for routinely determining crystalline silica concentrations at the 0.1 % RCS level. Most ores are extracted from silica-bearing deposits and it is a common constituent of rocks and soils. OSHA's RCS will have the greatest impact on the producers of crushed stone, diatomite, dimension stone, gravel, industrial sand, perlite, pumice, pyrophyllite, sand, and talc because these materials frequently are shipped directly from the mill to the customer. MSHA's RCS would affect nearly all mineral producers. Those producers that have crystalline silica present in concentrations near the 0.1 % cutoff point will have the most difficulty with the analysis. Crystalline silica can be quantified at the 0.1 % level by X-ray diffractometry in simple systems containing one, two, and possibly three minerals if (1) none of the accessory minerals has X-ray diffraction reflections that coincide or overlap with those of crystalline silica and (2) the standard has a particle size distribution and crystallinity similar to those of the sample. In some instances, it may not be possible to determine the crystalline silica content of a sample with any degree of certainty using the recommended regulatory protocol. In all cases, it is recommended that a qualified mineralogist identify the minerals in a sample prior to any regulatory analysis. Additionally, the uncertainty as to whether some silica polymorphs should be classified as crystalline or noncrystalline and the suitability of metastable high-temperature standards, such as cristobalite and tridyrnite, for regulatory analysis at ambient temperatures should be addressed further. This overview is written both to highlight these problems and to serve as a guide for analysts, regulators, and industry personnel who are involved in the crystalline silica issue. It also covers some of the difficulties and/or shortcomings in quantifying crystalline silica, such as the ubiquitous mineral quartz, in the workplace.

Jan 1, 1992

By V. A. Marple, K. L. Rubow, S. M. Behm

"An eight-stage cascade impactor, with cut-sizes ranging from 0.056 to 18 um at a flow rate of 30 L/min, has been developed, calibrated, and tested in field programs. This impactor, called a microorifice uniform deposit impactor, has several features not normally found in cascade impactors. Ultrafine particles as small as 0.056 um are collected while keeping the pressure drop moderate by utilizing multiple nozzles (up to 2000) as small as 52 um in diameter. At each stage the collected particles are deposited uniformly over the entire impaction plate by rotating the impaction plate relative to the nozzles and by the correct radial placement of the nozzles. The particle cutoff characteristics (collection efficiency curves) of each stage and inter-stage losses were determined by means of monodisperse aerosols. The cutoff characteristics were found to be sharp and similar for all stages.Inertial impactors are widely used for the size-selective collection of aerosol particles. One reason for their wide usage is that the principle of operation is simple: a jet of particle-laden air is directed at a flat impaction plate. Large particles are collected on the plate while smaller particles follow the airflow out of the impaction region and are not collected. The division between the size of particles collected and those that are not is quite sharp. Secondly, the particles in an impactor are classified by their aerodynamic diameter (an important size parameter in many fields of study, including those related to respirable particle health effects). Thirdly, it is easy to collect particles in discrete size ranges by passing the aerosol through a number of stages (one stage consisting of a nozzle and impaction plae) in series, with each subsequent stage collecting particles smaller than the one before it. This is known as a cascade impactor. Finally, impactors can classify particles over a wide range of particle sizes: as low as 0.005 um (Fernandez de la Mora et al., 1990) and as large as approximately 50 um (Vanderpool et al., 1987).This paper describes a general purpose cascade impactor that has been developed in our laboratory and used in a variety of studies including visibility studies (McMurry et al., 1986; McMurry and Zhang, 1989), underground mine studies (Marple et al., 1986; Rubow and Marple, 1988; Rubow et al., 1988), and general atmospheric pollution studies (Macias et al., 1981; Dzubay et al., 1984). The impactor, called a microorifice uniform deposit impactor (MOUDI model 100, MSP Corp., Minneapolis, Minn.), is the integration of two earlier impactor de¬velopments: the microorifice impactor (M01) (Kuhlmey et al., 1981) and the uniform deposit impactor (UDI) (Marple et al., 1981).The MOUDI has several features normally not found in other cascade impactors. These include collection of particles as small as 0.056 um in aerodynamic diameter with a moderate pressure drop, uniform particle collection on the impaction plates, inter-changeable impaction plates to allow for the plates to be easily and quickly changed in the field, and covers for these substrates to provide a means for safe storage and/or transport of the collected particles to the laboratory for analysis."

Mar 1, 1992

This report has been prepared in response to a request by the Bureau of Land Management (BLM) Fairbanks Alaska District Office that the Bureau of Mines quantitatively assess the potential supply of minerals from undiscovered deposits in the White Mountains National Recreation Area (WMNRA) and the western part of the North Steese National Conservation Area (SNCA) in Alaska. The assessment will be used to assist in future land-use decision-making. Resource Management Plans (RMPs) for the WMNRA and the SNCA were approved by the BLM in 1986. These plans imposed significant restrictions on new mineral development in the two areas. The level of public concern regarding these actions, especially on the part of the mining industry, has spurred BLM to seek additional information about the potential supply of minerals from the two areas with assistance from the Bureau of Mines. The assessment focuses on an area within the WMNRA and the SNCA which has been administratively closed to mineral entry. The study area encompassed approximately 1.24 million acres and included all of the WMNRA and the western portion of the North SNCA (fig. ES-1). Three quantitative estimates of the potential supply of minerals from the study area were developed: 1) For all lands in the study area, assuming that they are open to mineral entry-the baseline analysis; 2) For those lands which have been closed to mineral entry; and 3) For eleven prospective mineral activity areas, assuming that all are open to mineral entry.

Jan 1, 1989

By M. B. Balachandra

A three-dimensional finite element analysis was performed of an instrumented section of a double-entry coal mine in order to provide a comparison between field measurements and existing analytic techniques. The BMINES computer code was used to perform the analysis. The sequence of excavation of the entries was considered, as well as the installation of rock bolts and cribbing during the mining cycle. The materials In the region under investigation were idealized into four rock types and coal. The rocks were assumed to be isotropically elastic, perfectly plastic. Coal was represented by an elastically anisotropic (transverse isotropy) and plastically isotropic model. A fracture yield criterion of the Coulomb form was used for all materials. The strength and stiffness of all materials were substantially reduced from available laboratory data to account for in-situ properties. Qualitative trends and stress distributions obtained from the calculation were found to be reasonable. However, computed displacements and closures were greatly exaggerated and an excessive degree of inelastic deformation was indicated in the coal, especially adjacent to the excavated faces. It was established that both these effects were the result of an excessive reduction in the strength and stiffness of the materials. The analysis underscores the need for three-dimensional calculations by identifying a number of important structural response parameters that would be either outside the scope of, or misrepresented by, two-dimensional analyses. The analysis also emphasizes the need for comprehensive and accurate measurement of material properties in order fully to exploit the power of the analytical techniques to generate reliable predictions.

Jan 1, 1976

By Thomas J. Fisher, Christopher C. Jobes, Edward F. Fries

This report (Software Safety 2.2) is the third in a nine-part series of recommendations addressing the functional safety of processor-controlled mining equipment. It is part of a risk-based system safety process encompassing hardware, software, humans, and the operating environment for the equipment’s life cycle. Figure 1 shows a safety framework containing these recommendations. The reports in this series address the various life cycle stages of inception, design, approval and certification, commissioning, operation, maintenance, and decommissioning. These recommendations were developed as a joint project between the National Institute for Occupational Safety and Health and the Mine Safety and Health Administration. They are intended or use by mining companies, original equipment manufacturers, and aftermarket suppliers to these mining companies. Users of these reports are expected to consider the set in total during the design cycle. • 1.0 Safety Introduction.—This is an introductory report for the general mining industry. It provides basic system/software safety concepts, discusses the need for mining to address the functional safety of programmable electronics (PE), and includes the benefits of implementing a system/software safety program. • 2.1 System Safety and 2.2 Software Safety.—These reports draw heavily from International Electrotechnical Commission (IEC) standard IEC 61508 [IEC 1998a,b,c,d,e,f,g] and other standards. The scope is “surface and underground safety-related mining systems employing embedded, networked, and non networked programmable electronics.” System safety seeks to design safety into all phases of the entire system. Software is a subsystem; thus, software safety is a part of the system’s safety .• 3.0 Safety File.—This report contains the documentation that demonstrates the level of safety built into the system and identifies limitations for the system’s use and operation. In essence, it is a “proof of safety” that the system and its operation meets the appropriate level of safety for the intended application. It starts from the beginning of the design, is maintained during the full lifecycle of the system, and provides administrative support for the safety program of the full system. • 4.0 Safety Assessment.—The independent assessment of the Safety File is addressed. It establishes consistent methods to determine the completeness and suitability of safety evidence and justifications. This assessment could be conducted by an independent third party. • 5.0 Safety Framework Guidance.—It is intended to supplement the safety framework reports with guidance providing users with additional information. The purpose is to assist users in applying the concepts presented. In other words, the safety framework is what needs to be don and the guidance is the how it can be done. The guidance information reinforces the concepts, describes various methodologies that can be used, and gives examples and references. It also gives information on the benefits and drawbacks of various methodologies. The guidance reports are not intended to promote a single methodology or to be an exhaustive treaty of the subject material. They provide information and references so that the user can more intelligently choose and implement the appropriate methodologies given the user’s application and capabilities. [ ]

Jan 9, 2001

By K. E. Tame

Pollution from radioactive nuclides, principally Ra226, in liquid waste from uranium mills can be minimized by reusing the waste solution within the mill. Such reuse of waste solution in the Vitro Chemical Co.-type process was investigated in the laboratory. Vitro employs an acid leaching process for dissolution of the uranium, countercurrent decantation for liquid-solid separation and washing, and amine solvent extraction for recovery of the uranium from solution. The simulated reuse of barren raffinate in the mill circuit was carried through two separate laboratory campaigns of 29 and 31 cycles. Conventional chloride stripping of the amine was employed in the first campaign, whereas nitrate stripping was used in the second campaign. Dissolution of uranium from the are in the acid leaching circuit averaged 96 percent. Washing efficiencies of 98 to 99 percent were attained by using 4 volume tons of combined raffinate and makeup water per ton of ore. Uranium recovery from the pregnant solution using a 5-percent solution of amine LA-1 in kerosine ranged from 99.3 to 99.9 percent.

Jan 1, 1962

By Donald B. Lindsay

A new concept was proposed for a personal warning device for use by miners who may be exposed to health hazards from inhalation of alpha-emitting radionuclides, especially radon-222 and its short-lived daughters. Two successive prototype models of the proposed instrument were designed, fabricated and tested. The Personal Alpha Alarm, in its final form, weighs less than 90 g (3 ounces), and can easily he mounted on a miner's safety cap. It is powered r, by electricity drawn from the cap-lamp battery, and consumes less than 100 n A at 4VDC. It is entirely passive and has no moving parts. Alpha-radiation originating in the air around it is detected by a 5 cm2-area semiconductor-type sensor that was developed especially for this purpose. The presence of alpharadiation in the air is communicated to the wearer by means of a small flashing light-a light-emitting diode-clipped to the brim of the safety cap. When the intensity of alpha-radiation exceeds a predetermined threshold, the flashing mode changes to a continuous illumination, thus providing an alarm signal to the wearer. Because the detector senses all alpha-emitters in the air, including 222Rn, it is not able to measure Working Levels accurately. For its intended purpose, however, which is to give a timely warning of excessive levels (several times the normal control level) of radon and/or radon daughters in an individual's air environment, the Personal Alpha Alarm is expected to be a useful instrument.

Jan 1, 1978

By Richard F. Hewlett

Numerous populations of assays have been simulated for a range of assay values representative of low-grade mineral deposits to facilitate the study of problems encountered in evaluating these deposits. Analysis of these simulated populations of assays (obtained by using statistical probability models for the simulation) makes possible the quantification of the effects of (1) various composite assay intervals, (2) ore reserve computational methods, (3) uneven assay intervals, and (4) various cutoff grades on both the precision and the accuracy of the estimated average grade and tonnage of ore.

Jan 1, 1964

By ALBERT C. DURHAM

In anthracite mining , pumping is a problem of major importance , and water must be handled and rehandled in almost every mine whether the mine is in operation or idle . The motor - driven centrifugal pump is the most commonly used type of unit for the large pumping installations, and experience has . proved that fully automatic control has certain advantages over manual control . Some of these advantages are greater safety for maintenance personnel , continuous protection against faulty operation , which could cause damage to the Lumping apparatus , and lower pump -room operating costs .

Aug 1, 1948

By Maria I. De Rosa

Combustible materials, when burned, produce toxic gases and smoke, which may vary dramatically from one material to another, with resultant different total toxicity and smoke obscuration levels. This U.S. Bureau of Mines report presents smoke property data acquired for a variety of mine combustibles and shows that there exists a correlation between the smoke properties, the relative toxicity, and the smoke obscuration levels of those combustibles tested. These correlations can be used to devise simple, standard tests for determining the toxic and smoke obscuration hazards of mine materials during fire.

Jan 1, 1989

By J. S. Hansen

The U.S. Bureau of Mines developed a system for casting unique, slotted steel armor by modifying the conventional expendable pattern casting (EPC) process that is normally used for making aluminum castings. Three innovations were added to the EPC process to make the successful adaptation: (1) Vacuum was applied to sand molds, (2) continuous narrow-necked feeding systems were used to permit the casting of thin walls, and (3) fixtures were designed to prevent pattern damage and to hold critical casting tolerances, Potential problems and defects are described.

Jan 1, 2010

By John B. Bennett

In this report estimates are presented of the impact of the passage of five recently proposed "acid rain" bills on electric utility costs for coal-burning utilities servicing the domestic aluminum smelting industry, and on the costs of production for affected aluminum smelters. As aluminum smelting is an energy-intensive industry, domestic increases in electricity prices could affect the industry's competitiveness. Energy costs in U.S. aluminum smelting are compared to aluminum smelting energy costs in the rest-of-the-world. Governmental policies affecting these energy costs are discussed.

Jan 1, 1988

By J. W. Paul

This circular is one of a series of papers4 on coal-mining methods and costs which are being prepared through the sponsorship of the U. S. Bureau of Mines for the purpose of presenting information on present mining methods and certain features which govern costs, safety, and conservation. The methods employed are influenced by natural local conditions with respect to the thickness, character, and dip of the coal bed, the nature of the roof and thickness of the overbearing strata, and the means employed for roof support and its control.

Jan 1, 1929

By L. L. Hirst

Liquid fuel oils possess certain advantages over solid fuels. Ease in handling, precision temperature control, and almost complete freedom from ash are among those considered when a liquid fuel is selected for use in industrial processing. In some instances these fuels are desirable because more heating units can e packed in a Given space where space is limited, as on snips. In other cases the' are chosen because of lower actual cost per British thermal unit absorbed, or for control of the flame to increase the capacity of furnaces, as in steel and refining.

Jan 1, 1948

By Ad. Breyre

For more than 20 years, Belgium, leading all the coal-mining countries, has made increasing use of sheathed explosives, which wore first suggested by the late E. Lemaire, predecessor of the author gas Director of the Institut National des Mines. It appears to the author that it will be valuable to show how the use of sheathed explosives has developed in Belgium, how the various difficulties encountered in their manufacture have been overcome gradually, and the tyros of sheathing that have survived and the reasons for their survival.

Jan 1, 1940

By Ad. Breyre

For more than 20 years, Belgium, leading all the coal-mining countries, has made increasing use of sheathed explosives, which wore first suggested by the late E. Lemaire, predecessor of the author as Director of the Institut National des Mines. It appears to the author that it will be valuable to show how the use of sheathed explosives has developed in Belgium, hour the various difficulties encountered in their manufacture have been overcome gradually, and the tyres of sheathing that have survived and the reasons for their survival.

Jan 1, 1940

By W. W. Weller

Low-temperature heat capacities of scandium sesquioxide (Sc203) and a mixture of cerium sesquioxide (Ce203) and cerium dioxide (CeO2) were measured over the temperature range from 50° to 298° K. The entropy of scandium sesquioxide at 298.15° K was evaluated directly as S°298.15 = 18.4 ± 0.1 cal/deg mole. That of cerium sesquioxide was extracted by combining the heat-capacity data for the mixture with those for pure cerium dioxide; the result was S298.15 36.0 ± 1.0 cal/deg mole.

Jan 1, 1963

By R. N. Roby

In the course of the Bureau of Mines investigations for suitable sources of high-aluminum clay for the production of alumina, the Whiteware clay deposit was examined in August 1942 by G.N. Bennett, mining engineer, Bureau of Mines, Montana District Office. This report presents the factual data obtained by the investigation, which also includes data on trenching and drilling, and the results of some refractory tests and chemical analyses of representative samples of the clay later taken from some of the best trench exposures and from adit dumps.

Jan 1, 1949