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To develop a quick, safe, and effective method that allows workers at mineral processing operations to clean their dust-soiled clothing periodically throughout the workday. Background Reducing workers' respirable dust exposure to silica and other harmful dusts and contaminants is an ongoing goal in the U.S. mining industry. One area of known worker exposure is from contaminated work clothes. A U.S. Bureau of Mines report documented a number of cases where a tenfold increase in a worker's dust exposure was measured from contaminated work clothes. In these cases, the dust emitted from clothing caused the worker's dust exposure to exceed the permissible exposure limit in less than 2 hours. The most effective way to eliminate this dust source is to have workers clean or change their work clothes. There are two federal regulations that impact the clothes-cleaning process. The first states that at no time shall compressed air be directed toward a person, but that when compressed air is used, then all necessary precautions shall be taken to protect persons from injury. The second regulation states that compressed air should only be used for cleaning purposes when it is less than 30 psi and used along with personal protective equipment. For the mining industry, by default, the only approved method to perform clothes cleaning is to have workers vacuum their clothes using a HEPA filter system. This is very difficult and time-consuming and, in most instances, not very effective. Most workers would prefer to use a single compressed air hose to blow dust from their work clothes. However, not only is this method prohibited by law, it usually creates a significant dust cloud in the work environment and contaminates coworkers.

May 1, 2005

By E. D. Gardener, Byron O. Pichard

"Methane, frequently called fire damp or marsh gas, is very well known to coal miners but to thy average gold miner it means nothing, as it is not associated generally with the rock formations in which gold is found.We have recently been conducting a study of mine air in typical gold mines on the Pacific Coast, and out of five California mines in which the air was sampled, three showed methane. Each of these three mines, referred to below as mines A, B, and C, have had accumulations great enough to be ignited. An authentic report from another California, gold mine, which has not yet been sampled, states that recently the superintendent was seriously burned by the ignition of a pocket of gas. This mine is later mentioned as mine D.Mine A is an old mine which had been abandoned for several years and permitted to fill with water. It has been unwaterad recently, and is now being developed at greater depths. During the unwatering, gas bubbles formed on the water and upon being ignited burned freely. It is reported that two men were seriously burned from accidentally igniting the gas. Samples of the bubbles on analysis showed high percentages of methane. Since the mine has been unwatered, no trouble has been experienced through gas being ignited. However, out of a total of six air samples which we took recently in scattered working places, all showed small amounts of methane, the methane content being 0.06, 0.04, 0.05, 0.04, 0.04 and 0.07 per cent, respectively. When these samples were taken methane was not suspected, but its general presence in the mine air indicates that it is being given off constantly."

Dec 1, 1921

Aluminum alloys are used in two broad classifications: wrought and cast. Wrought alloy products, which are formed into final shape by rolling, forging, extruding. etc., contain low percentages of alloying elements; whereas cast aluminum products, which generally are not worked before use, may contain higher percentages and a somewhat different selection of alloying elements. For example, wrought aluminum alloys usually contain less than one percent silicon and cast alloys contain as much as 18 per-cent silicon. While there are good techniques available for separating aluminum alloys from mixed scrap, there are no efficient ways to separate wrought aluminum from cast aluminum. The high levels of silicon, iron) copper, and zinc from the cast alloys make wrought-cast mixtures unacceptable for wrought alloy production. Consequently, separated wrought aluminum scrap commands a premium price on the market. Since increasing amounts of mixed aluminum alloys are being recovered from automobile scrap, this separation is important for efficient recycling of these alloys. Approach The difference in thermo-mechanical properties between the two classes of aluminum alloys is used as the basis for the separation process. Casting alloys lose their ductility within a certain temperature range while wrought alloys remain ductile. As temperature increases, aluminum alloys gradually become weaker, and at a certain temperature, each alloy loses strength and ductility due to incipient melting in localized areas. For casting alloys that temperature generally lies between 520° to 560° C, but it is above 600° C for most wrought alloys. Mild crushing, therefore, in the proper temperature range will result in complete fragmentation of the casting alloys but only plastic deformation of the wrought alloys. A simple screening step then is used to separate the oversize wrought pieces from the fragmented cast alloys.

Jan 1, 1984

By D. N. Nilsen

The Bureau of Mines is developing a method to recover Ni, Co, and Cu from laterites containing less than 1.2 pct Ni and 0.25 pct Co. The method consists of the following basic unit operations: (1) reduction roasting, (2) leaching, (3) solvent extraction, and (4) electrowinning. The method reflects three Bureau of Mines objectives: (1) recovery of critical minerals that are domestically in short supply from low-grade domestic laterites, (2) lower processing energy requirements, and (3) solution recycling. This report deals with the extraction of cobalt and the preparation of a suitable cobalt electrolyte by solvent extraction from liquor produced by this method. Nickel and copper are coextracted with LIX64N from an ammoniacal ammonium sulfate leach liquor containing about 1.00 g/l Ni, 0.30 g/l Co, 0.03 g/l Cu, and 0.02 g/l Zn. Cobalt (III) in the nickel-copper barren raffinate is reduced to cobalt (II) with cobalt metal. Reduction of cobalt (III) to cobalt (II) greatly aids subsequent extraction. Commercially available XI-51 extracts about 94 pct of the cobalt from the treated raffinate in one stage in a laboratory mixer-settler continuous circuit. Ammonia loaded on the solvent is removed in two washing steps. About 94 pct of the cobalt then is stripped from the XI-51 in one stage with spent cobalt electrolyte containing about 77 g/l Co and 18 g/l sulfuric acid (H2S04), Electrolytes containing less H2S04 also may be used. Preliminary data indicate that coextracted zinc may be removed from pregnant cobalt eletrolyte containing 3 g/l or less H2S04 with di-(2 ethylhexyl) phosphoric acid (D2EHPA).

Jan 1, 1980

By Todd M. Ruff

An average of 13 mine workers are killed each year by being run over or pinned by mobile mining equipment. At surface mines, these accidents commonly involve large dump trucks that drive over a smaller vehicle or a person that is in the dump truck’s blind spot. One method of detecting a person or another vehicle in a blind spot is to use some type of sensor technology such as radar or radio-frequency identification (RFID). Researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health tested a number of commercially available and experimental sensors that monitor obstacles in a vehicle’s blind spots. None of the sensors had been previously applied to the specific problem of rigid-frame surface mining trucks. This report documents the procedures and results of tests conducted after RFID and radar systems were mounted on a 50-ton-capacity dump truck. It was determined that both RFID and radar technology show promise for detecting obstacles in the blind spots of mining equipment; however, more development work is needed to meet the unique requirements of mining equipment and the mine environment.

Jan 1, 2000

By Ernest J. Conway

Seventy-four human factors research and development projects were identified for possible Bureau funding. The projects were based on (1) literature surveys, (2) reviews of accident statistics and reports, (3) interviews with equipment manufacturers, MSHA, and Bureau personnel, and (4) site visits to 26 mines. The projects are divided into the following categories: those related to (1) mobile equipment, (2) maintenance shops and areas, (3) plants and mills, (4) organizational factors, (5) safety programs/data, and (6) training. The projects were rated by industry and MSHA people in terms of benefit to the industry. Projects were placed into three categories of priority. The highest priority contained 25 projects with 26 in Category 2, and 23 projects in the lowest category.

Jan 1, 1982

By C. Melvin Lepper

The Bureau of Mines has developed an improved earth resistivity field system which employs a novel technique for obtaining null measurements. The instrument is designed to operate reliably in high-noise environments such as those found in the vicinity of operating mines. The system consists of a low-frequency transmitter, a sensitive receiver and an external battery pack, each in its own case to provide protection from the elements. The receiver and transmitter units have self-contained recharge-able batteries to supply power to the circuitry and separate built-in battery chargers that operate on standard 115 Vac power. The system is portable and simple to operate. Measurement accuracy, reliability, and dynamic range are superior to most commercially available equipment even though less time and effort is required to make null readings. Unlike some commercial systems, long integration times are not required to enhance signal-to-noise ratio in areas of high background noise.

Jan 1, 1974

By Clark F. Grain

These investigations were undertaken as part of the Bureau of Mines program for the development and evaluation of high temperature nonmetallic materials. This report consists of thermal expansion and phase inversion measurements by high-temperature X-ray diffractometry on the principal oxides of beryllium (BeO), calcium (CaO), titanium (TiO2 ), zirconium (ZrO2 ), hafnium (HfO2), and thorium (ThO2); all were high-purity commercially available oxides. Thermal expansion values were calculated from unit cell dimensions measured at selected temperatures. Expansion was determined parallel to each major crystallographic axis for the anisotropic oxides: BeO, TOi2, ZrC2, and HfO2. Combined random and systematic errors in the thermal expansion values are considered to be less than 3 percent of the total expansion at 500° C. and approximately 2 percent at 1,000° C. No hysteresis in the expansion curves was noted between heating and cooling cycles. The Bureau's values were compared with published expansion measurements obtained by X-ray diffraction, dilatometric, interferometric, and telemicroscopic techniques. For anisotropic oxides, average linear expansion values were calculated from the volume expansion.

Jan 1, 1962

Electrical trailing cables are frequently damaged in usage, especially on continuous minors, and because of their weight and damaged condition present a safety hazard to personnel required to handle them. The U.S. Bureau of Mines and FMC Corporation signed Contract No. HO 122011 in August 1971. One of the contract tasks was to study the feasibility of techniques to improve trailing cable support and handling of power cables on underground coal mine machinery and to design a cable-handling device for a continuous mining machine. This report presents the results of the feasibility study, describes the design for a proposed cable handling device and concludes with a recommendation for future action to construct a test rig to evaluate the cable reel system.

Jan 1, 1972

By M. Kanda

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in and above an operating coal mine, McElroy Mine, located near Moundsville, West Virginia. The electromagnetic environment created by 300 volt dc and 480 volt ac machinery was measured. In one technique noise was measured over the entire electromagnetic spectrum of interest for brief time periods. The noise was recorded using broadband analog magnetic tape. The noise data was later transformed to give spectral plots. In the other technique, noise amplitudes were recorded at several discrete frequencies for a sufficient length of time to provide amplitude probability distributions. The specific, measured results are given in a number of spectral plots and amplitude probability distribution plots.

Jan 1, 1974

By G. A. Wancheck

Shear tests were performed on several prepared samples of granular and powdery bulk materials to investigate the following parameters: Particle size and distribution, particle movement, moisture content, consolidation of material, bulk density, void ratio, porosity, volume change, and strain rate. A series of shear tests was performed with weight-percent-ratios of minus 0.185-inch tertiary sand and 1-1/2-by l/2-inch tertiary gravel mixtures, and weight-percent-ratios of minus 200-mesh limestone (rock dust) and minus 200-mesh bituminous float coal dust. A comparison was made for shear test results obtained with rectangular and circular shear cells utilizing the large and small direct shear testers. Specifically, the shear results obtained include the angle of internal friction or shear strength of the tested material under known consolidating pressures, and the kinematic angle of friction or coefficient of friction between the interface of a bulk material and a sample wall material. The experimental procedure, tests, and results are given for each parameter investigated.

Jan 1, 1973

By BUREAU OF MINES

Mercury has been used by mankind since prehistoric times. It has been, and is now, widely used in industry and medicine and has unique properties which make direct substitution difficult or impossible. At present its prin- cipal uses are for electrical apparatus, control instruments, electrolytic soda preparation, mildew-proofing paints, pesticides, and medical and dental preparations. Deposits of mercury are less common than those of other base and precious metals, but some of the deposits are very large and have been ample to meet the world's past demands. The price of mercury has had many sharp fluctua- tions, but in general, the limited number of producers has resulted in a more stable price structure than that of many other commodities. The United States has been one of the main producers of mercury, and from 1850 to 1961 produced 3,247,704 flasks. Yearly production since World War II has varied from 4,535 to 38,067 flasks. An estimate of domestic resources of mercury producible at various price ranges was prepared for each mercury mine by combining specific knowledge of mercury mineralization with estimates of potential, based on geologic informa- tion and past production history. The sum of the individual estimates for each price range is shown in a table. A parallel estimate of nationwide production potential was made from a study of past price and production relationships. These were analyzed by plotting yearly production figures against the previous year's price, expressed in dollars of constant purchasing power. An equation was fitted to the data by mathematical means and was used to extend the curve into areas of higher than historic prices. Potential production rates at various price levels were taken from this graph. The estimated yearly production rates were used to make an estimate of total potential based on the premise that produc- tion rates and reserves have a proportionate relationship.

Jul 1, 1964

By D. Harrington

Although the hysteria. with regard to silicosis end other occupational diseases seems largely to haws passed, and more careful sober consideration is being given this subject, it would be very poor policy for any employer to take the stand that the storm has blown over and that he can safely relax and revert to the status of 5, 10, or more years ago in such matters. The real fact is that occupational-disease compensation is nor in its infancy and can be expected to grow by leaps and bounds. At present, while 46 States of the Union3/ and the District of Columbia have compensation acts, only the following have some fern of occupational-disease legislation: California, Delaware, Connecticut, District of Columbia, Illinois, India a, Kentucky, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Jersey, New York, North Carolina, North Dakota, Ohio, Pennsylvania, Rode Island, Washington, West Virginia, and Wisconsin. Silicosis appears to be compensable under those acts in California, Connecticut, District of Columbia, Illinois, Kentucky, Massachusetts, Missouri, New York, North Carolina, North Dakota, Ohio, Pennsylvania, West Virginia, and Wisconsin; possibly it may be interpreted as compensable in others. Occupational-disease legislation (largely relating to silicosis) has seen under consideration in some form relatively recently in Arkansas, California, Delaware, Idaho, Maryland, Kansas, Massachusetts, Michigan, Minnesota, Montana, Nebraska, New Jersey, Ohio, Pennsylvania, Tennessee, Utah, and. Washington at least. It will be surprising if comparatively broad or inclusive occupational-disease legislation will not be on the statute books of nearly every State in the Union within the next 5 years. With this situation confronting him, the far-sighted industrialist who has the best interests of his organization at heart will immediately begin to "put his house in order," if he has not already done so, by studying possible occupational-disease hazards to his employees; moreover, he will promptly apply all known remedial measures or will attempt to devise such measures if none of those already devised seem to apply to his establishment.

Jan 1, 1939

By W. M. Weigel

"Sand is one of the most useful and, fortunately, one of the most common mineral commodities. By far the largest proportion of the production is used in construction, including all forms of building, concrete and paving, sand for this purpose is produced in every State in appreciable amounts. Excluding send used for railroad ballast, molding sand stands not in tonnage produced, followed by glass sand.Special sands. In addition to the above, many grades of sands, with special characteristics, are used in industrial processes, and may be classed in a group as ""special sends"". This includes filter sand, sand blast sand, engine sand, abrasive send, fire or furnace send, special flooring sand, roofing sand used as a finish for prepared roofings and pottery placing sand sand blast and filter sand have been discussed in previous reports.Very few send companies depend upon the production of any one of these grades, as their source of revenue. They are generally especially prepared from the bank run of sand by different methods of screening or washing, or may, in some instances, be by-products from the production of ether grades. Many companies not now producing them might be able to supply local demands by a slight addition to their plant. In nearly all cases, they command a better price than the usual grades of building sand.Definitions and Properties.Engine sand, or traction sand, as it is sometimes called, is used to prevent the slipping of the driving wheels of locomotives, or other self-propelled vehicles, on wet or slippery rails. Its greatest use is, of course, for railroad locomotives, but street cars use considerable amounts and mine locomotives require its use. As the send must be very dry when used, most consumers have their can drying equipment, so it is often shipped damp, with its natural water content on what resulting from washing by the producer."

Oct 1, 1924

By Nancy Potts, M. G. Barker, W. C. Holliman

"SUMMARYThis report on the characteristics of commercial aviation gasolines presents compilations of inspection test data furnished on their products by manufacturers of commercial grades of aviation gasoline, and special data obtained in Bureau of Mines laboratories on samples of these gasolines. Data and physical samples for the survey were submitted by 15 manufacturers on 18 grade 80, 21 grade 91/98, 22 grade 100/130, end 10 grade 115/145 aviation fuels.The inspection test data supplied by the participating manufacturers consist of octane and performance numbers, tetraethyllead content, dye color, and other characteristics usually listed in aviation gasoline specifications, such as AN-F-48a or ASTM Designation D910-47T. These data are tabulated and averaged by grades in tables 1 through 4 and, as reported, meet the AN-F-48a and similar specifications with a few exceptions. Two grade 80 gasolines show a lean-mixture octane rating slightly below 80.0, and 91/98 grade fuel shows a lean-mixture rating of 90.9 and a rich-mixture rating of 97.5, two 100/130 grade gasolines have a rich-mixture performance number slightly below 130.0, and one 115/145 grade gasoline shows a rich-mixture performance number of 144.5. However, octane and performance number averages are above the mini¬mum requirements for each grade. Tetraethyllead content in the 91/98 and 100/ 130 grades generally is above the maximum outlined in these specifications, whereas dye color for each of the four grades, with the exception of two gasolines in grades 80 and 100/130, is that designated for the particular grade. Distillation requirements, with a few exceptions at individual points, are met by gasolines of all grades. Reid-vapor-pressure, copper-dish-residue, heat-of-combustion or aniline-gravity-constant, freezing-point, and copper-strip-corrosion requirements are met by all gasolines so far as reported. No data for some of these tests wore submitted on a few of the gasolines. One gasoline, grade 115/145, shows a sulfur content greater than the specified maximum."

May 1, 1948

By Frank E. Cash

As a part of its safety program the United States Bureau of Mines has fostered the development, use, and improvement of portable electric mine lamps. Although there is still need for better illumination in mines and the replacement of open lights has been slow, improvement in electric cap lamps and increase in their use indicate one phase of recent progress toward safer and more efficient mining This report is the result of a recent survey of electric-lamp installations in the Alabama mining; district; it shows the misuse, increase in use, and relation to certain classes of accidents of these installations.

Jan 1, 1935

By R. L. Mazza

This final report on methods of reducing and controlling methane in coal mine gob areas indicates that vertical degas holes are beneficial to the mines of northern West Virginia working the Pittsburgh Coal. The USBM funded project involved the drilling and testing of eight vertical holes (four over longwall panels and four over room and pillar panels) based on a review of 13 previously in existence. Areas of observation included gas production history, flow entry profile, underground methane reductions, strata separations, and casing loads (accompanying subsidence). Observations led to the drilling of successful holes drilled short of the mine. Eleven gas production response to applied vacuum tests were conducted at nine degas holes under the contract. Significant production responses were recorded over longwall gobs.

Jan 1, 1977

By E. F. Divers

This Bureau of Mines report describes the results of a program to develop small, rugged mechanical dust collectors (scrubbers) with high dust collection efficiency and low energy comsumption for controlling dust in coal mining operations. All of the scrubbers described are similar in configuration and are powered by 6-hp, 2,000-ft3/min vane axial fans. Air pressure differential is less than 6 inches water column. Height of the scrubbers? including fan is less than 14 inches, width is less than 16 inches, and length is less than 45 inches. The flooded fibrous-bed scrubber achieved respirable (less than approximatey 7 µm) dust collection efficiencies of 95 percent. The small-diameter-cyclone scrubbers showed about 92 percent efficiency and can be best where excess water is a problem. The wetted brush scrubber showed 88 percent efficiency at low cost, and the wetted fan scrubber showed a slightly lower efficiency (87 percent) but offered the smallest size and cost. A suitable water droplet eliminator is described.

Jan 1, 1978

By L. W. Higley

Electrowinning metals from solutions leached from low-grade ores is becoming an increasingly important extraction method as the metal industry turns to pollution-free recovery processes. Lead-alloy anodes are used industrially in the electrolytic recovery of zinc and copper. However, associated with the use of these anodes are the inherent problems of stability and lead contamination of the cathode. In an effort to eliminate these problems, the Bureau of Mines has developed a relatively inexpensive lead dioxide anode for electrowinning metals from strong acid solutions. The anode was prepared by depositing Pb02 directly on a titanium blank in a strong HN03-Pb(N03)2 solution at 2.15 to 6.45 A/dm2 and 60° C. This anode was tested in zinc and copper electrowinning cells containing 200 gpl H2S04 and 35 to 100 gpl metal ions at the current density of 3.23 to 6.45 A/dm2. Contamination of the cathode by lead was =0.005 pet. A 30-day test at 6.45 to 12.90 A/dm2 in an electrolyte containing 200 gpl H2S04 and no metal ions resulted in a slight change in surface morphology of the Pb02 anode but no measurable change in anode weight or dimensions.

Jan 1, 1976

By Charles L. Kimbell

Some comment on data availability must be an integral part of a study such as this. For many years, the centrally planned economy nations of the world regarded as state secrets much of their mineral commodity production information, as well as a considerable body of the foreign trade information on these commodities, and virtually all reporting on their consumption. Within the past 5 years, this pattern has undergone some evolution, and although these countries still fall short of market economy countries in their willingness to publish, there has been measurable improvement. Fit, China, and then subsequently the former CMEA member countries of Eastern Europe have released in print an increasing amount of information in organized, coherent formats, although in a number of cases it is not clear that the information provided is in perfect definitional accord with market economy country practices. Thus, these recently available statistics must be carefully studied to ensure that they are provided in terms of conventional market economy definitions. At the same time that heretofore unpublished information is becoming available for the centrally planned (or formally centrally planned) economy countries, there has been a slow but steady disquieting erosion of availability of production, trade, and consumption data for market economy countries. There are evident reasons for some of these losses in information. The foremost of these relates to corporate mergers. As the number of producing or consuming firms of a given commodity in a given political jurisdiction declines, it is increasingly difficult for government agencies to protect proprietary company data. In past years, this protection was afforded by aggregating data for the several companies operating in the area, but as the number of operators diminishes this is no longer always possible. Hopefully, given this situation, companies will at least authorize release of data after a period of time, when its publication will not provide competitors with unfair access, but will make possible longer term studies.

Jan 1, 1992