Search Documents

By J. V. Batty

Radioisotopes of selenium (se78) and tellurium (Te123) were successfully employed by the Bureau of Mines as tracers in metallurgical research directed to developing improved methods for volatilizing these elements from low-tenor raw materials. Prior research, guided and controlled by conventional analytical methods, was seriously hampered by inconsistent selenium and tellurium analyses, by the slowness of the conventional chemical methods, and by the poor accountability of these volatile elements in test products. Methods were devised and evaluated for admixing the radioactive tracer with typical raw materials and then following the deportment of the selenium and tellurium by radiometric methods with occasional chemical analysis checks. These techniques were found unusually effective in (1) quantifying the completeness and the rate of volatilization of selenium and tellurium while heating the raw materials at different rates to different temperatures and (2) accurately tracing and quantifying the distribution of minute amounts of these volatile elements in the several products made by high-temperature treatment and in the several units comprising the experimental equipment.

Jan 1, 1962

By Kent W. Hawley

An improved visibility system was developed for use on the large (100 ton+) haulage trucks typically operated in open pit and surface mines. The improved visibility system provides the truck driver' with a means of viewing hazardous situations that occur in the extensive blind areas adjacent to his true. The cost effective, reliable, visibility system consists of a closed-circuit television three unique fresnel viewers, and two improved mirrors. This report describes the visibility problems of Large trucks in the surface mining environment, shows the performance of existing mirrors, substantiates concept selection, and describes the prototype improved visibility system.

Jan 1, 1978

By M. P. Ristenbatt

A new automated post-disaster signaling system, intended to use through-the-earth EM propagation, was demonstrated in the laboratory at an input SNR of -34 dB. The system presently available requires an input SNR of +6 dB, and uses a human-ear detector. The work here demonstrated coherent integration, for the automated system, in multiples of 17 s, up to 1088 s (18 minutes). A repeating pseudorandom (or pseudonoise) signal is used, which offers an ideal auto-correlation at the receiver matched-filter output. A novel decision-variable algorithm achieves the estimate of noise level by using those matched-filter output samples that occur between the signal auto-correlation peaks. This work included corraboration that the received signal power decreases as distance to the tenth power, for through-the-earth propagation. Thus, the above 40 dB reduction in required input SNR permits an automated system to have a range 2.5 times that of the present system. In addition, an automated system permits the possibility of operating receivers around-the-clock; this would reduce the initial-detection-time from a few hours (present system deployment time) to a few minutes (signal processing time).

Jan 1, 1981

By D. E. Pollock, Andrew B. Cecala

It has long been known that ventilation is a cost-effective method to lower respirable dust concentrations in all types of mining applications. The National Institute for Occupational Safety and Health has been working on a number of different research techniques that use ventilation as a critical component to lower respirable dust levels at surface and metal/nonmetal operations in the United States. This article presents five such research efforts. The first research area discusses how improving the ventilation flow patterns in an iron ore mill facility lowered respirable dust concentrations by 31 pct throughout the primary grinding area. The second research area examines how respirable dust levels were lowered at a dimensional stone shop by using air cleaning units suspended from the ceiling. A third area discusses how improvements in ventilation at underground limestone mines lowered respirable dust concentrations. The fourth area examines how improvements in dust filtration and pressurization systems significantly impacted the air quality in enclosed cabs of surface mining equipment. The last area presents a newly developed clothes cleaning technique. This technique uses an air spray manifold to blow dust from a worker’s clothing in an enclosed booth, which confines the dust for capture and removal by a baghouse dust collector. These research areas represent an array of different control technologies to lower respirable dust concentrations. Ventilation is an integral part of these control technologies.

By Meherwan C. Irani

The Bureau of Mines is developing a new technological approach to handling the problems of fires in abandoned coal mines and waste banks. This new technology involves the accelerated combustion of "waste" coals in place (i.e., in situ) under controlled exhaust ventilation conditions, which allows for total management of the combustion products; including utilization of the heat produced" This new concept could significantly lower the costs of reducing the environmental and public safety hazards associated with waste coal fires, and could lead to the conversion of a coal waste to a coal resource. The controlled burnout technology has progressed from the laboratory stage to a full-scale field evaluation stage at the site of an abandoned-coal-mine fire. This first report describes the site selection, evaluation, and preparation, and the design and construction of the full-scale controlled burnout installation. Subsequent reports will deal with the results of the operational field trial.

Jan 1, 1983

By Forrest T. Moyer

To keep the mineral and allied industries informed of trends in the causes of accidents and to point out the need for corrective measures, the Bureau of Mines collects, analyzes, and publishes, periodically health and safety statistics. This report includes data for 1961 on injury experience, with related employment statistics, at coal mines in the United Status. These data are presented in tabular form under the following headings; General Injury Experience Tables 1 to 6: Current data on number of injuries, degree of injury, frequency and severity rates, average severity, and related employment and production data by work location.

Jan 1, 1963

By Neldon L. Jensen

Although ASARCO Incorporated, the only domestic producer, had terminated copper smelting operations and associated recovery of byproduct arsenic trioxide at Tacoma, WA, in 1985, it shipped small quantities of both trioxide and metal from its remaining stocks in 1986. Imports for consumption of arsenic trioxide increased significantly, owing to increased demand for arsenical wood preservatives and the decrease in domestic shipments of trioxide. Prices remained unchanged throughout the year. Development of gallium arsenide integrated circuits, important in advanced military and commercial electronics circuitry, continued to gain momentum during 1986. Domestic Data Coverage.-Shipments of small amounts of arsenic trioxide and metal from remaining stocks by Asarco were reported voluntarily to the Bureau of Mines.

Jan 1, 1988

By Stephen C. Tadolini, Steve Bessinger, James Pile, Christopher Mark

The San Juan Coal Mine, located near Farmington, New Mexico, supplies the San Juan Generating Station with more than 6 million tons of coal annually. To replace dwindling surface mine production, San Juan installed a longwall in 2002. The roof rock in much of the underground reserve consists of interbedded coals, carbonaceous shales, and mudstones. Roof support consists of fully-grouted roof bolts, both tensioned and non-tensioned, supplemented by modified cable trusses. Short-encapsulation pull tests conducted by San Juan’s geotechnical engineering department showed that some of the immediate roof layers provided variable bolt anchorage. To ensure that the roof bolts were obtaining the necessary anchorage, additional tests were conducted in a variety of locations. The results have been used to determine the optimum support design for different areas of the mine. Another series of tests evaluated the performance of several bolt and hole diameter combinations. The experience at San Juan Mine shows that short-encapsulation pull tests can provide the information necessary to improve ground control in variable roof conditions. It also illustrates how a pro-active geotechnical engineering program can be an essential component of a state of the art underground coal mine.

By W. R. Crank

[Rock bursts are phenomena associated with mining operations, particularly with deep mining, although they occur throughout a wide rump, of depth, from 600 feel downward. The intensity is usually in direct proportion to the depth, varying from a loosening and sloughing off to a violent rupture, giving rise to the term, "explosive rock." The more or less violent breaking of rock in mine working, tins been variously designated as " flaking," "pressure hoists," "strain bursts," "bumps," "quakes," and "air blasts," which indicate opinions as to cause and effect. The term "air blast" lots probably beat most widely used, and naturally so, as a more or less rapid movement of air often accompanying the more violent phenomena of rock failure. Furthermore, there is an implied if not definitely expressed degree of magnitude in the action designited by a given term and in the cause and character of the action. For example. flaking, pressure bursts, and quakes are terms ranged to indicate action of increasing magnitude; and pressure bursts, strain bursts. bumps, and quakes are ranged according to the cause and character of the action.]

Jan 1, 1929

By Donald E. Redmon

Industrial engineering departments perform staff duties and are most effective when sincerely supported by management. In accordance with the needs and desires of the mining companies involved, various industrial engineering functions have been adopted widely at western metal mines during the period 1950-60. Newly organized departments usually conduct method and equipment studies, work-measurement programs, and establish and maintain production standards. Supervisor-training programs and courses are effective in showing the relationship between supervisory responsibility and the purpose for which industrial engineering is practiced. Industrial engineering staffs of western metal mines are composed predominantly of personnel from within the companies. Experienced industrial engineers, not necessarily experienced in mining, frequently are hired by a company to help establish the department. Management consultants frequently are called upon to advise management and instruct department personnel in industrial engineering practices. Some departments have developed satisfactory industrial engineering programs without benefit of formal industrial engineering training or advice.

Jan 1, 1962

By M. M. Wong

The Bureau of Mines, under a cooperative research program with four lead companies, has investigated a nonsmelting process for the production of lead metal. The process, which would eliminate sulfur dioxide generation and minimize particulate lead emissions, involves ferric chloride leaching of galena concentrate to produce lead chloride, followed by molten-salt electrolysis of the lead chloride to yield lead metal and chlorine. This chlorine is used to regenerate ferric chloride in the leaching solution. The process was tested in an experimental unit with a capacity of 500 lb of lead metal per day. The tests were performed in three 10-day and six 5-day campaigns, during a period spanning 28 mo. The study was carried out using a southeastern Missouri lead concentrate. Typical lead recovery was about 98 pct. Process problems related to impurity buildup and control were studied. When copper and silver impurities were removed from the leaching solution, a lead metal purity of 99.999 pct was obtained. Lead-in-air levels and lead-in-blood levels of operating personnel were monitored. The process has potential for producing lead with minimum pollution, but is not ready for commercial utilization. Operation of a prototype commercial electrolytic cell and a full-scale pilot-plant investigation by industry are needed to evaluate the commercial viability of the process.

Jan 1, 1983

By R. J. Gunderman

A conventional trailing cable connection box on a continuous mining machine was modified by the addition of two innovative devices. These are a pressure vent to preclude buildup of high pressure due to an explosion in-side the enclosure, and a grommet-type cable entry to simplify and speedup cable entering procedures. The innovative devices were evaluated for eight and one-half months in a working section of an underground coal mine. Laboratory tests before and after the in-mine exposure show no measurable change in the devices. Following the favorable in-mine evaluation, technical performance criteria were defined to serve as the basis of approval for the use of the innovative devices. Additional tests to measure comparable gripping of the cable by asbestos rope, substitution rope materials and by the urethane grommet-type entry were included in this effort. Also, literature for the last 80 years was searched. Comments are provided as to how the innovative devices comply with 30 CFR Part 18.

Jan 1, 1982

By T. J. Driscoll

Methane-air mixtures can ignite as a result of sparking or rubbing of materials, particularly by impact involving light alloys and rusted steel where an exothermic thermite reaction can occur. This report reviews the published literature and describes a new method utilized by the Bureau of Mines for studying the processes occurring during collisions of light metals with rusted steels. The method involves measuring the spectra of sparks and explosions in methane-air mixtures using a photodiode array. Initial results obtained using magnesium and aluminum alloy 6061-T651 projectiles striking rusted steel are reported. These results indicate that the continuous parts of the spectra show a larger intensity for incendive sparks compared with nonincendive sparks, with the largest relative change in the higher energy, ultraviolet region. An unexpected shift of the intensity maximum for the continuous parts of the spectra towards the infrared region was observed for the more incendive sparks. Evaluation of rusted steel samples with electron microscopy, energy-dispersive X-ray spectrography, and Auger electron spectroscopy after they had been impacted by aluminum alloys indicated that aluminum was transferred to the steel in the form of islands that became larger as a function of increasing projectile velocity.

Jan 1, 1982

By J. R. Ross

A reconnaissance for sources of scandium and a metallurgical investigation of recovery methods for byproduct scandium from uranium mill solutions were conducted by the Bureau of Mines. The work on scandium was undertaken to obtain information on domestic resources and to explore and develop recovery procedures in consonance with the Bureau's long-range program for conservation and wise utilization of mineral resources. The element scandium is widely distributed in the earth's crust in trace amounts, but it seldom occurs as an important constituent in any mineral. An exception is thortveitite, (Sc,Y)2 Si207) a rare mineral that contains various amounts of scandium and yttrium and may contain up to 42 percent scandium oxide (SC203). Knowledge of the chemistry of scandium has expanded rapidly in recent years (1, 4, 9)4 but only fragmentary information is available about the metal because it is still largely a laboratory curiosity without established uses (2, 3). A recent study shows some of the physical proper-ties of the metal are (1) density of 3.05 grams per cubic centimeter) (2) melting point of 1,540° C, (3) hexagonal close-packed structure) (4) hardness of about 50 Brinell (500-kilogram load), and (5) an alloy behavior similar to yttrium and rare-earth metals (2). The price of $2,850 a pound for scandium oxide of 99.9 percent purity and $2,700 a pound for oxide of 99 percent purity reflects the scarcity and complex chemistry of the element.

Jan 1, 1962

By Pedro Lilienfeld

This Final Report describes a program whose objective was to design, develop, fabricate, and test an airborne mass monitor for unattended and recording measurements of the concentration of dust in mining environments. Sensing collection are performed by beta-radiation attenuation and inertial implementation respectively. The instrument is portable, battery or line operated provides a digital printout of the mass concentration during each selection sampling period, as well as the accumulated mass of dust, and the elapsed sampling time.

Jan 1, 1974

By D. E. Traut

A fluidized countercurrent ion-exchange system was developed, operated, and evaluated by the U.S. Department of the Interior, Bureau of Mines. The system consisted of integrated multiple-compartment absorption and elution columns in which the solution flows were continuous except for short periods when resin increments were withdrawn. The exchange of uranyl carbonate between a simulated in situ uranium leach liquor and a strong-base ion-exchange resin together with the subsequent elution with an ammonium chloride solution was studied. The effects of the number of sections, section height, amount of resin withdrawal, solution flow rate, and column diameter were investigated. The kinetic and equilibrium relationships for the absorption and elution steps were also examined. The experimental data indicate a strong interdependence between variables. Solution retention time appears to be a major limiting variable in the absorption process, while resin residence time is the determining factor in the elution process. The column was efficient over a range of conditions, but close control was needed for optimum operation.

Jan 1, 1978

By R. Q. Shotts

Factors of geological structure and occurrence of coalbeds, plus the resulting mining conditions, have required more care in preparing coals in Alabama than in most other districts almost since mining Alabama coals began. For this reason, literature on these coals may be interesting to those in areas where prime coals have been mined out, and thinner and less regular beds must now be exploited. This literature review has been arranged in order of subject matter. Some references have been listed more than once, but each separate review is limited to the material pertaining to the subject matter being discussed. For those seeking specific information, the authors have indicated which items repeat material and which items are most complete or specific. Geology, preparation, and carbonization of coal have been reviewed the most frequently.

Jan 1, 1963

By George S. Rice, F. B. LANEY, A. J. Lanza, Edwin Higgins

Under its organic act the Federal Bureau of Mines is directed to conduct investigations relating to the improvement of health conditions in the mineral industries. This report describes the lead and zino deposits and the mining methods employed in the sheet-ground area of the Joplin district, Missouri, and discusses the causes and the methods of abating rock dust in the mines, the chemical and physical characteristics of the dust, and the quantities present in mine air. Although the preliminary investigation included a number of the "soft-ground" mines, the writer spent the larger part of his time in the sheet-ground mines, for in them alone was siliceous dust found in appreciable quantities. Some results of the preliminary investigation have been published by the Bureau of Mines in Technical Paper 105.a The territory covered in t~lCpreliminary investigation, during the period between November 7 and December 6, 1914, embraced parts of Jasper, Lawrence, Newton, and Greene Counties, Mo., and outlying districts in Kansas and Oklahoma. The remainder of the field work, to which 84 days during the period from February 9 to July 19, 1915, were devoted, was confined to the sheet-ground mines, the most important of which are situated in the vicinity of Joplin, Webb City, Carterville, and other smaller near-by towns in Jasper County, Mo.

Jan 1, 1917

By F. L. Wideman

This paper is one of a series on mining methods being published by the Bureau of Mines. It describes briefly mining practices at the Sunrise iron mine of the Colorado Fuel & Iron Corp., Platte County, Wyo. The Sunrise mine is in the Hartville iron district in east-central Wyoming (fig. 1). The district covers part of the Hartville Mountains, a region of moderate relief in which erosional features have been formed by the dissection of a low plateau. Altitudes vary from 4,300 feet along the North Platte River to 6,000 feet in the uplift. The climate is semiarid, with hot summers and winter temperatures below zero for short periods. Grasses, cacti, yucca, and low desert shrubs grow at lower elevations. Cottonwood and boxelder trees and willows grow along permanent streams; juniper and coniferous trees are confined to the higher elevations.

Jan 1, 1956

By R. F. Zaffarano

Intergrated energy balances and energy flows were constructed and quantified for State, regional, and national levels from four separate supply and demand commodity balances for coal, dry natural gas, petroleum and natural gas liquids, and utility electricity. These commodity balances were integrated by source and sectors through conversion and aggregation of their components to energy equivalents expressed in British thermal units (Btu). A summarization of the total gross energy components of supply and demand for commercial energy derived from direct fuels, hydropower and nuclear power, based on individual States and regions, is tabulated for 1960 and 1965. Pertinent computerization details and more than 500 individual State and regional printout tables, in both original commodity units and Btu's, are shown. Using these data, energy flows between States and regions were calculated to identify surplus and deficit energy areas. Report emphasis is on the conceptual aspects of integrated energy balances, rather than on the development of missing State energy data.

Jan 1, 1969