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By P. D. Kovscek

The performance of a novel prototype kerf-cutting impact mining machine was evaluated under a cooperative agreement between the U.S. Bureau of Mines and RAMEX Systems, Bellevue, WA, while operating under conditions typical of normal tunnel entry development. Selected operating parameters were monitored concurrently to determine baseline operating conditions and to study relationships between operating parameters. Using the data obtained, the specific energy requirements of the impact mining machine were calculated and compared to specific energy requirements of tunnel boring machines cutting in rock having similar hardness. Tests results indicate that the kerf-cutting impact mining machine can provide a mechanical means for mining very hard rock that cannot be effectively mined using commercially available mechanical excavators.

Jan 1, 2010

By Erie C. Donaldson

Gas-displacement tests were made in Berea Sandstone and Arbuckle Lime-stone cores to determine the relative permeabilities to gas, oil, and water for two-and three-phase dynamic systems. Three-phase relative permeabilities were obtained by displacing oil and water from the core with gas and measuring the flow rates of the three fluids simultaneously. It was found that relative permeabilities to fluids in a porous medium are affected by the saturation distributions of other fluids in the medium as well as by their own saturation distributions.

Jan 1, 1966

By David H. Yee

Because of environmental concerns, the Bureau of Mines investigated an anhydrous chlorination process for the recovery of copper from chalcopyrite, Pelletized concentrate was reacted continuously with chlorine in a vertical shaft reactor at 550° to 750° C to extract copper-iron chlorides and elemental sulfur. The resulting molten metal chlorides drained from the reactor and collected in a receiver while sulfur distilled from the top and condensed in a separate unit. The tests were conducted in a 10-cm-diam reactor constructed of glass and in l5-cm-diam reactors constructed from various refractory materials. A high-alumina ramming mix exhibited the best resistance to molten metal chlorides and elemental sulfur in chlorine atmospheres. A reactor made with this high-alumina refractory was operated for 55 hr under actual chlorinating conditions without suffering any deterioration. Tests results show that more than 96 pct of the chalcopyrite was converted to copper-iron chlorides and elemental sulfur. Good separation of the metal chloride and sulfur products was achieved. After filtration, elemental sulfur of greater than 99 pct purity was obtained.

Jan 1, 1977

By R. H. Lien

The Bureau of Mines investigated nitrous oxide (N20) stability when used as a solvent for organic removal from metal powder surfaces. Both supercritical and subcritical conditions were studied. This investigation was prompted by the occurrence of a violent reaction when supercritical N20 was being used to deoil a metal powder grinding waste sample that contained 20 to 25 wt pct cutting oil. Tests were conducted to determine the cause of the reaction and to define stability limits. Test data showed that the waste's oil fraction reacted violently with N20 acting as an oxidizer; the metal powder acted as a promoter to reduce the ignition temperature. Although the data were scattered, this temperature appeared to reach a minimum at a certain pressure (dependent on vessel and sample size). The minimum ignition temperature for a 0.64-g sample in a 72-cm3 vessel was 360° C at 200 psig. As the sample size increased, the ignition temperature decreased. For example, when the sample size was increased to 10 g, a reaction occurred at 240° C and 600 psig. Because of the variability of ignition temperature with pressure and sample size, safe operating conditions were not established. Overall, this research showed that extreme caution should be exercised when using N20 in an organic or organic-metal system.

Jan 1, 2011

By Van H. Manning

"Under the organic act establishing it, the Bureau of Mines is authorized to conduct investigations designed to improve health and safety conditions in the mineral industry and to promote efficient development and utilization of our mineral resources. The field of the Bureau's activity, therefore, begins with the commercial development of mineral deposits and ends with the production and utilization of the final marketable product.In order to serve more efficiently the various sections of the country, the Bureau has established, in addition to its main offices at Washington, D. C., eleven field experiment stations, three field offices and several mine rescue cars and mina rescue stations. These field branches are so distributed as to cover most of the mining districts of this country, including Alaska. The field service in general deals with specific experimental problems, cooperative work with non-governmental institutions, and mina rescue work, while the Washington office is the administrative head and is responsible for the distribution of general information, the chiefs of the technical and administrative divisions of the Bureau being stationed there.The Bureau is prohibited by law from doing work exclusively for the benefit of any private company or individual. Generally speaking, the Bureau does no assaying, ore testing, or similar service work for the benefit of private companies or individuals. In response to requests for work of this sort a list of assay and ore testing laboratories is supplied. In referring inquiries to com-mercial laboratories or consulting engineers, care is taken to mention several names so as to avoid designating any one establishment or engineer."

Apr 1, 1920

By Wilbur I. Duvall

A linear array of shot and gage holes 30 feet deep in a granite outcrop was used to compare the size and shape of radial strain pulses produced in the rock when short cylindrical charges of cast composition B were detonated axially or at one end. The axially detonated charges produced radial strain pulses that had shorter rise times and larger peak strain than the strain pulses produced by end detonated charges.

Jan 1, 1965

By H. H. Schrenk

There are several well-recognized procedures for controlling exposure to hazardous atmospheres in industry. They include (a) substitution of less toxic material, (b) enclosure of processes, (c) wet methods, (d) local exhaust, (e) general ventilation, and (f) use of respiratory protective devices. In addition to their employment as a control measure in occupational exposures, respiratory protective devices also are essential in emergencies that may arise from failure or improper use of other control equipment. Respiratory protective devices usually are employed to supplement other methods of control, as temporary expedients, or when other methods are not readily applicable or practicable. It seems reasonable to assume, however, that where respirators are used consideration has been given to the factors involved and that the devices can provide satisfactory protection if used properly. Their use should not be arrived at simply by a process of elimination of other methods that are more difficult to apply.

Jan 1, 1943

By Jack R. Woodyard

Bonding angles, promotion energies, and relative atomic sizes can be estimated through the solution of a set of algebraic equations generated from simple atomic models, and quantum mechanical parameters such as bond strength can be estimated from simple, hydrogenic form-wave functions. The precepts of The Engel-Brewer Theory are melded with the "Crystal Approximation Model" to produce atomic-structure models making these predictions, The two-valence-electron case is presented in this report. For the candidate atoms Be, Mg, Ca, Sr, and Ba the calculated promotion energies agreed within a few percent of their experimental values. These atomic parameters determine the possible crystal structure of the candidate atoms when alloyed. This is part of the effort at the U.S. Bureau of Mines to develop methods for alloy design in response to requirements for new high-performance alloys that conserve critical or rare materials.

Jan 1, 2010

By E. P. Youngman

This paper is one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate-mines in various foreign countries. This interpretation of the mining laws of Greece was prepared from information furnished by Ralph B. Curren, American assistant commercial attache, Athens, in reply to a questionnaire of the United States Bureau of Mines, transmitted through the courtesy of the commercial laws division of the Bureau of Foreign and Domestic Commerce. INTRODUCTION In his report,3 Mr. Curren states that the source of his information was the Director of Mines of the Greek Ministry of National Economy and the Mining Code of Greece, which was, compiled from existing laws in 1929,4 and which has since been modified by several acts of Parliament.

Jan 1, 1932

By A. Oyler

The U.S. Bureau of Mines has compiled data on the major causes of fatal and nonfatal electrical accidents related to mining, and their associated costs, for the 1980-85 period. Specific electrical problem areas were identified, allowing future research to be focused on reducing the frequency of these occurrences. Recommendations for reducing the number of electrical accidents and injuries are provided. The four mining sectors for which data were gathered and compiled are (1) underground coal mines, (2) surface at underground coal mines, (3) underground metal-nonmetal mines, and (4) surface at underground metal-nonmetal mines. Nine categories of information pertaining to specific aspects of the accident are used in this report: activity engaged in when the accident occurred, source of injury, job title, mining method, location, machine, nature of injury, accident type, and part of body affected. The number of years of experience at the specific job the employee was performing when the accident occurred, time of accident, and in the case of nonfatal accidents, the total days lost per year, are also summarized.

Jan 1, 1990

By T. H. Dubaniewicz

Many mines rely on toxic gas sensors to help maintain a safe and healthy work environment. This report describes a prototype monitoring system developed by the U.S. Bureau of Mines (USBM) that uses light to power and communicate with several remote toxic gas sensors. The design is based on state-of-the-art optical-to-electrical power converters, solid-state diode lasers, and fiber optics. This design overcomes several problems associated with conventional wire-based systems by providing complete electrical isolation between the remote sensors and the central monitor. The prototype performed well during a 2-week field trial in the USBM Pittsburgh Research Center Safety Research Coal Mine.

Jan 1, 1995

By C. Q. Cupps

n view of increased interest in secondary recovery of oil in the Cut Bank field, Montana, a review has been made of unpublished data obtained during a 1943-44 study of reservoir oil characteristics in this field. Considerable uncertainty was attached to interpretations of subsurface oil sample analyses from six Cut Bank zone wells, one Lander sand well, and one Moulton sand well, because of adverse sampling conditions and wide range in the data. Much of this uncertainty has been removed by this review which has shown two of the Cut Bank zone samples and the Moulton sand sample to be representative of the reservoir oils. Estimates of original reservoir oil characteristics derived from differential-liberation analyses of these samples show that the oil in the Cut Bank zone was initially saturated at the gas-oil contact pres-sure, 750 psia, and the oil in the Moulton sand was undersaturated with a saturation pressure of only 380 psia. The rest of the samples were indicated to be nonrepresentative of the reservoir oils because of a disproportional vaporization of heavier components of the solution gas. The vaporization of these components is believed to be a cumulative effect of contact of the oil with bypassing, light-gravity gas which had been liberated at higher pressures from solution in oil farther back in the formation, or which had come from the gas cap, rather than from the singular effect of gas evolution caused by excessively low bottom-hole pressures. Change of oil composition caused by the latter was found to conform closely to that occurring during a differential liberation of gas in the laboratory.

Jan 1, 1967

"Introduction.The Bureau of Mines has taken up the problem of determining a method or methods whereby underground compensation insurance rates for metal-mining companies can be equalized in proportion to the underground hazards involved. This study has been started by the writer with the assistance of Mr. I. M. Wolfin* as consultant.The present paper briefly reviews the origin of accident compensation, gives a digest of State compensation laws, and describes types of insurance carriers. This will be followed by study of the basis of premium rate, risk differentials, and cost of compensation insurance to mine operators. These data will be supplemented by an analysis of the accident hazards in different mining methods and practices, and the severity and frequency of accidents classified by time lost and period of exposure to hazard, for different States, mining methods, occupations and nationalities. Attention will be given to standardized preventives for underground accidents in metal mines, and, finally, the classification of underground metal-mining hazard for workmen's compensation insurance premium rating."

Mar 1, 1924

By A. P. Grossman

'This report was prepared by Shell Oil Company, Mining Ventures Department in accordance with Cooperative Agreement No. 14-09-0070-b53 dated September 10, 1976, between the United States of America, Department of the Interior, Bureau of Mines and C(b) Shale Oil I Project, Ashland Oil Inc., Shell Oil Company, Operator. After completion of this report the Shell Oil Company withdrew from participation In the C(b) Shale Oil Project and advised the Bureau of Minus that plans for publication of this report had also been withdrawn. The Bureau of Mines acting under terms of the Cooperative Agreement hereby releases this report for general information.

Jan 1, 1976

By W. M. Myers

"The continued expansion of modern industry broadens the markets for minerals and their product. With these increasing demands new uses are being found for minerals that heretofore were considered as possessing no commercial possibilities. This tendency is reflected in the nonmetallic field in a constantly increasing demand for minerals formerly considered to be of scientific interest only, Furthermore, nonmetallic minerals of established commercial importance are used in new ways in various products, and this tends to expand the markets for these minerals. Some recent outstanding developments in applications of minerals are given in the following pages.The Andalusite GroupAmong the minerals that until recently were considered of scientific interest only, may be listed those of the andalusite group. This group is composed of the three minerals, andalusite, cyanite (or kyunite), and sillmanite, which are all forms of the compound Al2SiO5 (A1203, S1O2), and are therefore identical in chemical composition, but differ in physical properties,"

Mar 1, 1924

By Paul M. Tyler

The enormous deposits of greensand in New Jersey and elsewhere in the United States, many of them close to important octant industrial centers, constitute a perpetual challenge for research chemists to convert them into a commercial asset of national importance. Following the introduction of more concentrated fertilizers, comprising synthetic mixtures of more soluble salts, the quantity of greensand used directly upon the soil has diminished, but deposits of such material still have at least potential value locally for use not only as fertilizer but also as a water softener. An annotated bibliography of the already extensive Literature on greensand, virtually complete to about the end of 1929, has been issued by the Bureau of Mines3/, and the commercial aspects as well as the technology of greensand utilization are discussed in available publications, The purpose of the present circular, therefore, is merely to provide a brief outline of certain general essential considerations for use in appraising the potential value of a greensand deposit in any given locality.

Jan 1, 1934

By Joseph Grumer

The range of composition of gases synthesized from solid fuels which are exchangeable with natural gas on current gas appliances was evaluated by theoretical principles. These principles consider primarily the flashback, blowoff, and yellow-tipping characteristics of air-entraining burner flames. It was found that complete identity between the synthetic and natural product is not necessary. Gases such as may be obtained by hydrogasification of coal and other solid fuels without the removal of unreacted hydrogen offer advantages in flame characteristics. Between 25 to 37 percent hydrogen can be tolerated in the sendout gas.

Jan 1, 1965

By Floyd G. Anderson

The increasing trend toward use of continuous-type mining machines created a significant dust problem in coal mining, which resolved itself into three categories: Visibility at face, deposition on return airways, and the potential health hazard. The control measures applicable to these conditions and studied or developed from 1955 through 1957 are summarized and reviewed in this report. Other important problems brought into focus during the same period were radiation exposure in uranium mining and high temperature and humidity. Although temperature and atmospheric pressure alone may not be contributing factors in the incidence of silicosis, the few mining companies who operate under the extremes of these conditions are dust conscious and keep dust-control engineers on their operating staffs.

Jan 1, 1961

By C. C. Merrill

Studies were made to determine the amenability of yttrium to fused-salt electrorefining in a controlled atmosphere. Tests were conducted in a LiCl- YCl3 electrolyte system at 710° C. The major variables studied were the YCl3 content of the electrolyte, from l.7 to 13.4 mol percent, and the initial cathode current density, from 410 to 1,630 amperes per square foot. Vacuum distillation was employed to remove salt from the deposited metal. Metallic impurities, except for lithium, could be reduced to near or below their lower analytical limits, ranging from 10 ppm for Cu to 300 ppm for Ta; reduction of oxygen content, however, was accomplished only in metal produced from electrolytes with 5.4 mol percent YCl3 or less. Initial cathode current density had little effect on the purity of the product.

Jan 1, 1967

By Maria I. De Rosa

The U. S. Bureau of Mines performed experiments to determine if the primary gas toxicities evolved during the early (~300° C) and later (~400° C) combustion stages of chlorinated polyester-reinforced mine ventilation ducts could be predicted by a smoke particle characteristic, for the development of a test parameter. The experiments were conducted in an approximately 20-L furnace, at 14-min durations at set furnace temperatures of 2500 and 1,000° C, with an airflow through the furnace of 10 L/min. The variables studied, as a function of time, were the hydrogen chloride (HCI), carbon monoxide (CO), carbon dioxide (C02), and oxygen (02) concentrations, furnace temperatures, the sample mass weight loss, the average smoke particle diameter (dg and average number and concentration (no), and the product of the average smoke particle diameter and concentration (dgno). Results show that the inverse of the smoke particle diameter-concentration product [(l/dgn0)], correlates directly and significantly with the primary gas toxicities evolved during both early (HCI) and later (CO) stages of combustion.

Jan 1, 1989