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By D. Harrington

The prevention of accidents to children from blasting cans is of vital importance not only to everyone using commercial explosives but to the country at large. The manufacturers of explosives have realized this danger for years and have attempted to publicize the hazards of allowing blasting caps to fall into the hands of children. Unfortunately, many of tie users of explosives have failed to realize the danger or have ignored their responsibilities in the matter. Investigations of accidents to children from blasting caps (and scores of them occur annually) reveal that most of them are caused by blasting caps picked up or made easily accessible to the victims. The children who are blinded, maimed for life, or killed are in large part the innocent victims of the carelessness, thoughtlessness, or negligence of their elders, by whom blasting caps are left lying about, carried in the pockets, dropped or lost around blasting operations, stored away and forgotten, or left in places where trey can be found or are accessible to children. Many such accidents occur to children under 12 years of age, when they are still curious or inquisitive. One of the first reactions of a child upon finding a blasting cap is to investigate and "see" how it is made or how it "works." A blasting cap in itself, with one end open, invites a child to poke it with a nail, piece of wire, or some other object to see what is inside; or he may attempt to break it open with a rock or hammer. A lighted match could be thrust into the open end, and there are numerous other approaches, may of which can result in serious accidents.

Jan 1, 1944

By A. L. Engel

The Stayton Mining District in San Benito County, Calif., near Hollister, includes several square miles with many occurrences of antimony ore. The sample submitted for the test described in this paper came from a vein said to have been traced and sampled for 5,000 feet on the surface, 1,500 feet carrying 2-1/2 to 3 percent antimony and the remainder 1/2 to 2 percent. Thirty thousand tons 'With a content of 3 percent antimony are said to be blocked out. A drift of 200 feet on the vein has shown ore containing 4.2 percent antimony. The present sample assayed 3.8 percent. Previous flotation investigation of this are resulted in a recovery of only 71.6 percent in concentrates containing 56.8 percent Sb. It was desired to develop a method of treatment that would give better results. The antimony in the sample occurred as the mineral stibnite, Sb2S3, antimony sulfide.

Jan 1, 1949

By Laxman S. Sundae

A U.S. Bureau of Mines designed and fabricated in-seam tester (1ST), retrofitted with a dust shroud, was used to establish a respirable dust index (RDI) and to determine cutting forces from a variety of bit types in four coal mines and a salt mine. Results from cutting tests at four coal mines showed that radial bits required the lowest cutting force and the least specific energy. Generally, for each conical bit the RDI and cutting force increased when the included bit tip angles increased from 70° to 90°. During field tests it was not possible to measure the total quantity of respirable dust produced by each cut; therefore, attempts were made to determine the amount of dust that became airborne from each test cut. The test results show that the quantity of airborne respirable dust is very erratic and cannot be related to bit type. Two statistical methods were employed to analyze RDI, but no correlation was found between the RDI and bit type. Despite scatter in test results for RDI, significant difference was found in RDI generated in four coal seams. In general, RDI increased with the increased cutting force for each coal seam from mine 1 through mine 4.

Jan 1, 1989

By Thomas L. Ochs

The Bureau of Mines is investigating the fundamental behavior of electric arcs in electric furnace operations. The electric arc is a poorly understood phenomenon. If the arc in a steelmaking furnace can be more carefully controlled, it should be possible to increase heat transfer to the melt, reducing both electrical and acoustical noise. As a first step toward a better understanding of the are, voltage and current signals from operating furnaces were analyzed. The results of the initial analysis show that instrumentation used in monitoring and controlling furnaces, such as meters and strip-chart recorders, gives incomplete or erroneous information to the operator and therefore leads to less than optimal control. Advanced instrumentation and analysis techniques, such as the waveform analysis used in these investigations, can improve the understanding of operation and the control of electric furnaces. This report describes the instrumentation and the numerical analysis methods used and compares these methods with standard metering and recording techniques.

Jan 1, 1986

By G. L. Neumann

The Guymard mine in Orange County, N. Y., is reported to have been discovered in 1862 and mined until 1876, producing 10,000 tons of lead and zinc ore. The property was examined by an engineer of the Bureau of Mines in 1948. Development work was done by the Bureau in April and May 1949 and March 1950. During these two periods four drill holes totaling 2,090 feet were completed. The mineralized sections of the core were sampled and assayed.

Jan 1, 1952

By John B. Gayle

During studies of the various methods for determining and specifying the factors that indicate whether a particular coke is better or worse than other cokes for metallurgical uses, questions arose as to the precision of screen-analysis tests on coke. Although the usual index of precision, the standard deviation of the test result, gives a measure of the precision of these data, the experimental determination of the standard deviation for a particular set of conditions requires tests on a large number of duplicate samples. Because this procedure necessaily involves a great deal of labor, an equation for predicting standard deviations from theoretical considerations has been developed. Results predicted with this equation agree satisfactorily with the experimental values and are applicable to tests on coal, coke, gravel, and other bulk materials.

Jan 1, 1952

By James M. Nishi, Lloyd Carpenter

Sixteen elements were determined spectrochemically in the general range of 3 to 1,000 ppm in high - purity columbium . Samples were converted thermally to Cb2 O , mixed with graphite and Ge02 , and excited for 15 seconds using a 15 - ampere dc arc . For the molybdenum determination , the oxidized samples were mixed with NaCl and Geo₂ and excited for 30 seconds . Spectra were recorded on photographic plates , and spectral line transmittance values were measured photometrically . Relative - intensity ratios of selected analytical and internal standard spectral lines were plotted against concentrations of standards to form curves from which concentrations of impurities were read . Average precision of the method was 11.2 percent relative standard deviation .

Jan 1, 1964

By Frank E. Cash, Max S. Petersen

The use of safe equipment, safeguards, and safe practices in the mining and allied industries should reduce injuries and improve accident experience. The object of this report is to give to the mining industry, especially metal mining, a graphic pictorial description of some of the safeguards, equipment, and practices used and followed in the iron-ore mines of the Lake Superior district. Some of the subject material has been in use or has been established for many years, and some is relatively new. Some of the equipment was purchased commercially, and some was designed by the company employees and constructed in the mine shops. The photographs were taken by the personnel of the Health and Safety Division of the United States Bureau of Mines, primarily for use in the Metal-Mine Accident-Prevention Course of the Bureau of Mines. In general, they are arranged under the following headings or subjects: 1. Accident statistics. 2. Support of ground. 3. Hoisting and haulage. 4. Explosives. 5. Fires, gases, and ventilation.

Oct 1, 1948

By J. R. Boyle

The Bureau of Mines developed cost estimates fur the disposal of phosphate rock washer slimes by pond settling, from a study of the method used at the International Minerals a Chemical Corp., Moralyn Phosphate Operations, Polk County, Fla. Data were obtained by basing phosphate production and slime generation statistics on plant capacity rather than on actual company records. Cost estimates, which were prepared as a guide in evaluating alternative disposal methods and in identifying needed areas of research, could be applicable to any Florida plant using the same disposal method. To conserve mineral resources and to improve environmental conditions, the Bureau recommends further research directed toward developing alternative methods of disposal, including the recovery of water and P205 values from the slimes.

Jan 1, 1969

By Lucien Eaton

This paper describing the mining practices at Mine No. 1, Menominee Range, Mich., is one of a. series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. It is felt that the publication of this information will be of interest and value to the mining industry at large and especially to operators whose mining conditions are similar to those described. ACKNOWLEDGMENTS The author is indebted to the superintendent, engineer, and mining captain of Mine No. 1 for much of the information presented.

Jan 1, 1929

By Frank D. Lamb, D. A. Woodard

"INTRODUCTION The iron-ore deposits near Cranberry, N. C., were worked as early as 1820, and records show that to date at least 1,500,000 tons of ore has been mined.. The early operators depended on selective mining and hand cobbing to yield a product containing 40 to 50 percent iron. Later, a magnetic concentrator was erected by the Cranberry Furnace Co. and was operated periodically until 1930. The magnetic cobbing method employed yielded satisfactory concentrates, but the plant was shut down because costs were too high. 4/Early in 1944, in connection with the sponge-iron program of the Bureau of Mines, North Carolina and Tennessee were surveyed for the purpose of finding a readily available source of high-grade iron ore for use in the experimental production of sponge iron at Salisbury, N. C., and samples from various sources were tested in the laboratory. The Cranberry ore proved to be best with respect to grade of magnetite concentrates produced, and it was decided that a pilot mill should be built on the Cranberry mine property and that the concentrate made there should be shipped to Salisbury for direct-reduction tests in a commercial brick kiln."

Dec 1, 1946

By Richard W. Lewis, Lloyd Carpenter

The objective of the investigation was to determine spectrochemically 19 elements in the general range of 0.5 to 1,000 ppm in high - purity hafnium and its compounds . Samples were converted thermally to hafnium dioxide , mixed with buffer - carrier - internal standards , and excited by a dc arc . Spectra were recorded on photographic plates . Transmittance values were recorded densitometrically and converted to relative - intensity ratios . Four groups of standards were used to establish analytical curves from which the concentrations of impurities were obtained . Average precision of the method was 14.2 percent relative standard deviation , and relative error was 4.2 percent .

Jan 1, 1964

By Harry W. Campbell

In 1984 and 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied part of the Meadow Valley Range Wilderness Study Area (NV-050-156) in order to evaluate its identified mineral resources. The study area is located in Clark and Lincoln Counties, NV, about 50 miles northeast of Las Vegas, NV. The Johnston and Fitchett prospect, in the northern part of the study area, has more than 3 million tons of marginal perlite reserves suitable for many commercial uses. A preliminary mining feasibility estimate suggests perlite could be profitably mined from the study area; however, it is unlikely these perlite deposits will be developed in the foreseeable future because of unfavorable market conditions. Zeolite minerals occur in alteration zones adjacent to perlite deposits at the Johnston and Fitchett prospect, but high quality material is closer to potential markets. A metalliferous black shale unit containing 800,000 tons of subeconomic resources may extend into the study area at the Bradshaw vanadium prospect on the northwest boundary. Limestone, stone, sand, and gravel occurrences are wide-spread, but other suitable deposits in the region are more accessible to potential markets. Seven prospects in and near the study area were examined. The entire study area is leased for oil and gas exploration. A group of perlite placer claims covering more than 480 acres was located in the 1940's in the northern part of the study area. A small group of lode claims was located in the mid 1950's in the southwest part of the study area. No mining claims are currently (1985) held inside the study area. No mineral production is known from within the study area.

Jan 1, 1987

By P. J. Coleman

Research in the field of mining safety and health in the United States plays an important part in protecting the lives of miners. The National Institute for Occupational Safety and Health (NIOSH) Mining Program conducts surveillance, studies and developmental work aimed at improving the safety and health of miners. With recent reviews of the Mining Program by the National Academy of Sciences and the Mining Program response (NIOSH, 2008), the importance of setting goals, conducting high quality engineering and scientific research and evaluating the outputs, outcomes, relevance and impacts of these projects has been reemphasized. Surveillance of reported injuries is a first step in deciding on research directions and in designing specific projects. Groups of injuries often share features and attributes that suggest common causes and may respond to similar preventive efforts. Identifying groups of injuries also serves to prioritize intervention efforts. The Mine Safety and Health Administration (MSHA) Accident and Injury database (MSHA, 2008) provides individual case reports of mining injuries, illnesses and certain no-injury accidents (events such as roof falls that stop mine production or miners? activities for more than one hour). This database is an indispensable resource for researchers and stakeholders needing information on the statistics of these events. From an epidemiological perspective, research projects target groups of miners at risk due to specific patterns of work, equipment, mine settings and the management of safety and health in their mines. Incidence rates are provided by the MSHA data for selected variables, such as surface/underground location, standard industrial classification and state. While incidence rates are the preferred measure for all variables, denominators are not typically available; for example, to more clearly under-stand the data about injury by occupational type, it would be necessary to conduct demographic surveys. A current survey of the demographics of the mining industry should be complete by 2010, which will allow incidence rates to be developed for a number of variables such as age, occupation and experience. This survey will provide the first update of its kind since the first survey was conducted in 1985.

Jan 1, 2010

By R. Barany

The heats of formation at 298.15° K of calcium tungstate, calcium molybdate, and magnesium molybdate were determined by solution calorimetry. For the heats of formation from the elements, the values obtained were calcium tungstate, -402.4 ± 0.5 kcal/mole, calcium molybdate, -369.5 ± 0.3 kcal/mole, -334.8 ± 0.2 kcal/mole. For the heats of formation from the oxides J the values obtained were calcium tungstate, -49.2 ± 0.4 kcal/mole, calcium molybdate, -39.6 ± 0.1 kcal/mole, and magnesium molybdate, -12.9 [ ] 0.1 kcal/mole.

Jan 1, 1962

By Frederick K. Allgaier

This is the first in a series of progress reports on the longwall subsidence research program at the Bureau of Mines Denver Research Center. As part of this program, the Bureau and the Utah Power and Light Co. are cooperating on a study conducted at the Deer Creek Mine, which is directed toward developing the capability to estimate the surface subsidence resulting from longwall mining in a geologic, topographic, and mining environment common to coalfields in the Western United States. A monitoring network has been established at the Deer Creek Mine to measure subsidence over four adjacent longwall panels. To date, two panels have been mined. Subsidence began as the first panel was mined and continued for 1 year following completion of the panel, during which time the adjacent panel was mined" A maximum of 2.7 feet of subsidence occurred over the two longwall panels mined at a depth of 1,500 feet. Because of the length of time that subsidence continued after mining, the final subsidence profiles and angle of draw have not yet been determined.

Jan 1, 1982

By R. R. Wells

This report summarizes the results of laboratory investigations by the Alaska Mining Experiment Station, Juneau, to determine the practicability of treating cinnabar-stibnite ore by bulk flotation and controlled-atmosphere roasting of the concentrate. Ore from the Red Devil mine near Sleetmute, Alaska, was selected for testing; it is typical of ores widely distributed throughout the Kuskokwim River Basin. The material, consisting of stibnite and cinnabar in ankerite, dolomite, and quartz, assayed 1.55 percent Hg and 2.87 percent Sb. Continuous treatment of the ore in a laboratory flotation circuit recovered 95.7 percent of the mercury and 82.6 percent of the antimony in a concentrate that assayed 20.4 percent Hg and 34.6 percent Sb.

Jan 1, 1958

By C. E. Jordan

The fundamental properties of dielectric separation were studied to provide insight into the design and operating characteristics of a dielectric separator. Force equations on mineral particles were derived and evaluated experimentally. Responses to variations in the electrical voltage and frequency, feed rate, particle size, dielectric fluid, and dielectric constant were tested theoretically and experimentally, using a 5-cm-diam dielectric separator. High-dielectric mineral recovery was proportional to the calculated effective dielectric force volume (EDFV) that surrounded each drum-electrode wire. Electrode spacing was the most sensitive design parameter; spacing of less than 0.4 cm was required for a good separation. Dielectric separation was effective for separating minerals with dielectric constants that differed by approximately 2 or more.

Jan 1, 1985

By C. A. Geffen-Fowler

This report, sponsored by the Bureau of Mines, presents the results of an examination of the safety of the Blind Shaft Borer (BSB) shaft sinking system and an alternative modified BSB design concept in comparison to conventional shaft sinking technology. Detailed study of the two systems was also performed to identify and recommend design changes for optimum safety conditions. A comparison of the BSB systems with conventional shaft sinking was made on the basis of relative risk levels. Risk incorporates both the frequency and the potential consequence of accidents. A safety evaluation of the component operations of the two BSB systems was performed using a Failure Modes and Effects Analysis (FMEA) methodology. The results of this analysis show generally that both BSB systems are safer than conventional shaft sinking. The potential risk of conventional shaft sinking operations could be reduced by over 30%, on the average, with the use of the original BSB system, and by an average of about 10% with the modified BSB. Design change recommendations to further improve the safety of these systems include better fire suppression systems, improved man haulage systems and more compact hydraulics. An operational safety manual was also developed for the modified BSB system.

Jan 1, 1981

By D. H. Carlson

The U.S. Bureau of Mines and Michigan Technological University (MTU) are collaborating to develop an apparatus for measuring diesel tailpipe emissions in underground mines. A tailpipe emissions measurement apparatus (EMA) is described that dilutes diesel exhaust and measures the concentrations of diesel particulate matter (DPM), CO, CO2, NO, and NO2 at known dilution ratios. The EMA was evaluated by side-by-side comparison of its measurements with those by laboratory-grade instruments. Concentrations of CO and CO2 measured by the EMA were usually within ± 14 pct of concentrations measured by laboratory-grade instruments for CO and ±20 pct for CO2. EMA¬ measured DPM concentrations were, on average, 29 pct lower than those measured by laboratory-grade instruments, with the differences being fairly consistent. The CO and CO2 differences are related to the method of calculating the EMA's dilution ratio, and the difference in DPM concentrations is attributed to thermophoretic and/or condensation losses related to the EMA's unheated sample probe. Preliminary analysis of data obtained with a heated sampling probe and modifications in the sampling procedures have indicated reduced variability in DPM and in the calculated dilution ratios.

Jan 1, 2010