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By Kenneth M. Earl

In its investigation of deposits of strategic minerals, the Bureau of Mines did same development drilling at the Perkiomen Creek deposits, 5 miles east of Phoenixville, Pa. This area was the center of much copper mining from 1851 to 1858. The most productive vein was the Perkiomen-Ecton mines, owned by the Perkiomen Consolidated Mining CQ. The mines were closed in 1858, and no further production has been recorded. The Perkiomen-Ecton vein ranges in thickness from 2 to 19 feet. The principal mineral of value is chalcopyrite, with minor amounts of galena and sphalerite. No definite record was found as to the grade of ore min d. It was reported that 617 tons of 18-percent copper are obtained by hand sorting 12,200 tons of mine-run ore was shipped in 1851-1852. To cut the vein below the old mine workings, the Bureau of Mines diamond-drilled five holes aggregating 2,216.2 feet. The vein, where intercepted by drilling, carried narrow stringers of copper, lead, and zinc minerals.

Jan 1, 1950

By D. C. Dahlin

The U.S. Bureau of Mines investigated the magnetic susceptibility of minerals as a function of mag-netic field strength to determine how it might affect the potential for high-field magnetic separation as an alternative to other separation technologies. Single-mineral concentrates were prepared from specimens from the same deposit to compare magnetic susceptibilities of minerals that occur together and from specimens from different deposits to compare magnetic susceptibilities of like minerals. A vibrating-sample magnetometer with a superconducting magnet capable of producing a magnetic field of 7.16 x 106 Aim (90 kOe) was used to measure the magnetic moment of the samples. The data were then converted to specific magnetic susceptibility data and plotted as a function of magnetic field strength. Cursory studies were also completed on the effects of iron content and oxidation roasts on magnetic susceptibility in high fields. The results showed that magnetic susceptibility is essentially constant in magnetic fields above those needed to saturate ferromagnetic constituents. Although magnetic susceptibility is influenced by iron content and by thermal treatment, the changes are not large enough to influence separations in fields above 1.59 x 106 Aim (20 kOe).

Jan 1, 2010

This Part describes a mine pager phone to public telephone interconnect sys tem that permits mine paging telephones to be selectively interconnected with the public telephone system, as illustrated by Figure 1. This interconnect concept was first conceived and demonstrated in breadboard form by H. E. Parkinson of Industrial Hazards and Communications, PMSRC, as one means for providing improved emergency and off-hours communications. The third-generation prototype unit described in this Part was designed and fabricated by Arthur D. Little, Inc. This unit is a small desk-top or wall-mounted unit that connects directly to both the public telephone line and the mine pager phone line, and requires no modifications to either the public dial telephone or mine pager phones. As part of this task, ADL also built, under a very compressed time schedule, a second-generation prototype unit suitable for reliable demonstration of the interconnect concept during the Bureau's technology transfer seminar on mine communications in March 1973. * A major objective of the design of the third-generation unit described in this Part was that it be compatible with present mine pager phone systems utilizing DC voltage on the mine phone line to activate the phone loudspeakers. Therefore, this unit was designed to operate in a push- to-talk, push-to-listen mode that accommodates the inherent design differences and operation modes of the mine phones of different manufacturers. Though this push- to- talk, push- to-listen mode of operation may seem slightly unusual at first sight, we have found it is easily learned by new users. However, mine phone manufacturers wishing to expand their product lines with such an interconnect system will probably find it to their advantage to customize the design of this system to their particular mine phones, thereby utilizing the unique attributes offered by their individual product lines. This customization should not be difficult, and Section III below suggests some of the features that can be easily added to future designs. Detailed parts lists and circuit schematics for the present third-generation proto- type system can be obtained from the system manual submitted to PMSRC and placed on public file.

Jan 1, 1974

By W. P. Diamond, J. R. Levine

The explosion hazard of methane-air mixtures has become an increasingly serious mine planning problem, and an advance assessment of methane gas potential can therefore be essential for a safe and economic mine development pro- gram. As part of its coal mine health and safety program, the Bureau of Mines has developed a simple, inexpensive test to measure the methane content of coal samples obtained from exploration cores. The gas content of coal per unit weight as determined by the direct method test can be used as a basis for a preliminary estimate of mine ventilation requirements, and to determine if degasification of the coalbed in advance of mining should be considered. Since the Bureau began measuring the gas content of coal samples in 1972, experience has led to equipment and procedural changes, the most significant of which has been the development of a ball mill for crushing the coal sample to release the residual gas at the end of the desorption test period. This revised procedure replaces the crushing box and graphical methods described in earlier Bureau publications. The results of 583 direct method tests are summarized in tabular form. These results include data on the gas content of 125 coalbeds in 15 States.

Jan 1, 1980

By Ronald D. Hill, Elmore C. Grim

Mining as an extractive process alone is outdated and unacceptable to today's environmentally concerned public. Multiple land use must be considered as well. Only through effective preplanning can the full potential of reclamation result in a lasting asset for future generations. The coal industry is now recognizing that reclamation of mined lands is part of the mining cycle that must be planned and carried out in a timely and orderly manner. It is also finding that planning reclamation in advance of mining is cheaper and more effective than waiting until mining is completed. The decision to open a strip mine must be based on the results of studies to determine if successful reclamation can be achieved and whether the economic benefits to the company will be justified(1). Information regarding the physical, chemical, hydrologic and biologic systems operative at the site must be under- stood or reclamation will be a failure. Working together, engineers, management and reclamation specialists should design the actual mining and reclamation plan before mining is begun.

Jan 1, 1974

By S. R. Zimmerley

As a result of the drilling program of the Mining Division, Bureau of Mines, large amounts of manganese ores have been blocked out in the Drum Mountain District of Utah. The ores, as mined, would not be acceptable for the production of ferromanganese, and this investigation was made to determine their amenability to concentration by ore-dressing methods and the amount of

Jan 1, 1942

By H. -F. Krausse

Roof failures in underground coal mines are related to the lithology and geologic structure of the roof. There are two distinct suites of roof rock above the Herrin (No. 6) Coal in Illinois, and each has distinctive patterns of structure and roof failure. In black shale-limestone roof areas, roof instability is correlated with thinning of limestone beds and presence of faults and clay dikes. In gray shale roof regions, the prime roof hazards are posed by rolls, shear bodies, and presence of coal or carbonaceous partings in the roof. Most structural features examined are believed to have formed during early stages of sediment diagenesis and compaction. Structural trends and lithologic patterns are strongly interdependent for this reason. In many cases geologic patterns are so complex and locally variable that prediction of roof stability far in advance of mining is difficult. The need for greater flexibility in roof control planning is apparent.

Jan 1, 1979

By Oliver Bowles

"In a previous report of the Bureau of Mines (Serial No. 2080 reference was made to a fatal accident from falling rock in a quarry in Utah, and ways of avoiding such accidents were pointed out. A fatal accident similar to it in some respects recently occurred in a limestone quarry in Maryland. All operators of stone quarries are desirous of reducing accidents to a minimum, and almost without exception they welcome any suggestions having in view the establishment of safer quarry practice. It is believed, therefore, that a brief outline of the cir-cumstances surrounding this later accident may be of practical advantage to quarry-men, as it may serve as a guide to them in so conducting operations that such unfortunate occurrences may be reduced in number.The quarry where the accident occurred is in form a circular pit 500 to 600 feet across an 80 to 100 feet deep. The rock is a dense limestone with the beds dipping at an angle of 35 to 45 degrees from the horizontal. Numerous erosion cavities in the form of pockets or narrow spaces following joint planes are filled with red sand and clay. They are confined largely to the upper 20 or 30 feet of the deposit. Open bedding planes are 4 to 10 feet apart toward the surface, and are spaced at wider intervals toward the base of the quarry. The open bedding planes present smooth uniform rock surfaces that dip steeply into the pit at the northeast side of the quarry opening. These smooth surfaces constitute a source of danger, as they may permit loose material to slide into the pit.In this particular instance a blast had been discharged, throwing down a mass of rock for steam-shovel loading. Three men wore employed thereafter for a period of about two days in cleaning down all loose material that might be dangerous to workmen luring the loading process. A mass of red sand and clay in which several large bowlders were embedded was left on one of these slanting surfaces, for the material seemed to be sufficiently secure to be quite safe. The lower edge of the slanting surface was about 25 feet above the quarry floor. The quarry conditions are illustrated in fig. 1, where (a) represents the quarry floor, (b) the vertical quarry (c) the slanting joint plane surface, and (d) the rock and earth resting on the surface."

Dec 1, 1921

By J. S. Dunning

The objective of this research by the U.S. Bureau of Mines was to determine the effects of AI additions on the sulfidation resistance of Fe-Cr-Ni alloys. A series of Fe-Cr-Ni alloys with and without -additions of 4 pet AI were tested in a wet S vapor atmosphere at 677 C. A study of the morphology and composition of corrosion scales indicated a different corrosion mechanism for AI-free alloys compared with AI-containing alloys. Aluminum-containing alloys formed a compact, tightly adherent layer at the metal-scale interface that reduced corrosion rates by a factor of 3 to 10 compared with that of AI-free alloys. The thin, adherent AI-containing scale limited inward diffusion of 0 and S to the base metal and outward diffusion of Ni from the base metal. Aluminum-containing alloys formed a three-layer scale in oxidizing-S environments, while AI-free alloys formed a less protective two-layer scale.

Jan 1, 1989

By Terry S. Cory

This report is a comprehensive summary of the results of the propagation measurements program conducted for the US Bureau of Mines under Contract H0366028. Data was gathered in the MF frequency range from a cross sample of six mines representative of the industry having typical wireless requirements. From the raw data which was gathered, a logical method of data reduction is presented which culminates in a set of average attenuation characteristics for all mines visited. These characteristics define a typical MF wireless system when the communication range requirements are known. Direct through-the-earth propagation and the range enhancement mechanism due to coupling on and off conductors are evaluated and related to the planning of a typical wireless MF communications system.

Jan 8, 1977

By L. H. Harrison

In coal mines equipped with electrically driven mechanical mining equipment, the problem of protection for electrical circuits and machinery important, because the hazards of fires and explosions resulting from electrical failures is greater than in most other industries. There is need for better methods and improved protective devices for this service. Studies and tests designed to determine possible value of the short-circuiting contactor as an electrical device for coal mine service were investigated. Preliminary made to determine the operating characteristics of the device, after which tests were made under actual service in three coal mines. Ordinarily, electrical protection in coal mines is divided into three classes, as follows: 1. Overload protection that is intended to protect against damage from overheating and excessive mechanical strain due to overloading. 2. Short-circuit protection that provides a means of de-energizing the equipment instantly when an accidental short circuit occurs in the equipment or on the power system. Short cm protection tends to damage from fires and, explosions resulting in the dissipation of large amounts of electrical energy in a short circuit. 3. Ground fault protection that, in its various forms, is intended, to maintain the frames of electrical equipment at or near the same potential surfaces in contact with the earth for the purpose of safe-guarding human life.

Jan 1, 1951

By Dale E. Wittmer

Nonoxide ceramic materials could substitute for high-temperature alloy steels containing imported critical and strategic materials such as cobalt, chromium, and nickel if their high-temperature properties can be improved. An important result of this substitution would be a reduction of the Nation&apos;s need for imports of critical and strategic materials. In this Bureau of Mines investigation, the primary objective was to produce high-purity u1trafine (particles <5 ~m equivalent spherical diameter (ESD)) alpha-silicon carbide (a-SiC) powders with improved high-temperature properties using the Bureau&apos;s patented turbo-milling process. A secondary objective was to determine the feasibility of using polymer mill construction materials as a means of eliminating metal contamination from the turbomill. U1trafine a-SiC powders with BET (Brunauer-Emmett-Te11er) surface areas from 30 to 35 m2/g (~0.06 ~m particle ESD) were produced in an all-polymer turbomi11. These high-purity powders (with I-pct Band I-pct C additions) hot-pressed to greater than 99 pct of their optimal density and exhibited properties commensurate with those of commercially available a-SiC. The most promising of the construction materials tested for the major wear surfaces of the turbomi11 was u1trahigh-mo1ecu1ar-weight (UHMW) polyethylene, a polymer thermoplastic.

Jan 1, 1984

By W. F. Marshall

This report describes exhaust-emission data from 10 diesel engines: six 4-cycle, direct-injection, naturally aspirated engines; two 4-cycle, direct-injection, turbocharged engines; one 4-cycle, precombustion-chamber, turbo-charged engine; and one 2-cycle, direct-injection engine. These engines were tested over a 3-year period (1968-70). Lowest emissions were obtained with a precombustion-chamber engine. Emissions from the 2-cycle, direct-injection engine fell within the range of emission rates for the 4-cycle, naturally aspirated, direct-injection engines. Excluding the precombustion-chamber engine and excepting one of the 4-cycle, naturally aspirated engines, carbon monoxide emission rates were about the same for all engines tested. Test data on smoke, odor, and emissions of hydrocarbons, oxides of nitro-gen, carbon monoxide, and aldehydes are given.

Jan 1, 1971

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

CALCULATION OF MINE HEAD LOSSES FROM ALTIMETER SURVEY DATA USBM PENNSYLVANIA STATE UNIVERSITY - MINERAL ENGINEERING DEPARTMENT USBM USBM USBM THIS PROGRAM CALCULATES PRESSURE LOSSES USING THE USBM METHOD GIVEN USBM IN USBH IC 7809 BY MCELROY AND KINGERY.1957. THE MAJOR DIFFERENCE USBM BETWEEN THIS PROGRAM AND THE CITED REFERENCE IS THE TREATMENT OF AIR USBM

Jan 1, 1977

By E. D. Gradner

During 1924 a number of lives were lost and other men incapacitated by the toxic effects of gases produced in blasting in massive sulphides. In one mine, three men working in a raise were caught by gases from blasting a drift round in massive sulphide on the level. The round in the drift was shot ahead of time and it was necessary for the three men to travel through the gases to the intake air course. Two of the men lost their lives, and the third was injured, apparently for life. Other men at this same mine have been caught in the gases at blasting time and seriously injured. At a second mine, the gases from blasting in sulphides appear to be very dangerous, and it was necessary to send a number of men who were caught in such gases to the hospital. One man who was seriously gassed has not recovered in over a year is time. Another man similarly gassed soon died of influenza.

Jan 1, 1926

By D. H. Platt

Gypsum and gypsite, used in the manufacture of plaster and plaster products, have been mined from deposits near Acme, Hardeman County, Tex., for more than 30 years. The Certain-toed Products Corp., 120 East Lancaster St., Ardmore, Pa., operates the Acme, Tex., mine. Underground hauling was done with storage-battery and Diesel-electric-powered shuttle cars. Many mining companies and individuals have manifested interest in all types of equipment powered by Diesel or Diesel-electric units, as attested by the recent increase in use of Diesel-powered equipment in underground metal and nonmetal mines. The purpose of this paper is to describe the manner in which a storage battery-powered Joy Model 60D2 shuttle car was converted to Diesel-electric power. The conversion was made, at the instance of the operating company, by Stewart & Stevens on Services, 4801 Lemon Ave., Dallas, Tex. This is believed to be the only such converted shuttle car in use.

Jan 1, 1950

By Byron S. Gottfried

This Bureau of Mines report presents a method for combining the distribution curves at different specific gravities of separation, for a given piece of coal-cleaning equipment and a given raw coal feed, into a single, generalized distribution curve normalized with respect to specific gravity and, therefore, independent of the specific gravity of separation. Illustrative generalized distribution curves, based upon Bureau of Mines collected data on industrial operations, are presented for five different types of coal-cleaning equipment. The well-known concept of probable error is extended to the generalized distribution curve. It is shown that the conventional probable error is directly proportional to the specific gravity of separation. A number of sample calculations, illustrating the use of the generalized distribution curve and generalized probable error, are presented in the appendix.

Jan 1, 1977

By Joan T. May

Federal Bureau of Mines studies showed that some organic amine hydrochlorides can be used as dehydrating agents for producing anhydrous magnesium chloride from hydrates and brines. Laboratory-scale tests showed that double salts are formed by reacting 35 percent magnesium chloride brine or spray-dried magnesium chloride with pyridine hydrochloride. Heating decomposed these double salts to anhydrous magnesium chloride and recycle pyridine hydrochloride. Pyridine hydrochloride also chlorinated any magnesium oxide in the spray-dried magnesium chloride. The anhydrous magnesium chloride obtained by the method described contained less than 0.8 percent oxygen. More than 98 percent of the organic amine hydrochloride was recovered.

Jan 1, 1978

By G. S. Scott

In the course of tire investigation into the causes, behavior, and control of mine fires, which the Bureau of Mines is now conducting, come attention was given to the subject of spontaneous heating. It is self-evident that the temperature of a pile of broken coal will rise if the rate of generation of heat exceeds the rate of heat dissipation and will fall if the opposite is the cane. Factors that affect the rate of generation of heat are:

Jan 1, 1941

By Robert F. Randolph

Introduction This paper is a descriptive analysis of injuries and fatalities at small surface bituminous coalmining companies in Pennsylvania. The purpose of analyzing a specific industry sector and location is to identify issues that might be missed in a wider analysis. Other studies of small mine safety (e.g., Peters and Fotta, 1994, Randolph and Boldt, 1997) have shown that the relationship between safety and mine size is not a simple one. Some injury types occur at higher rates at small mines, while others occur at lower rates. Consequently, an analysis limited to a specific type of mining can help identify hazards and issues specific to that sector. The results of this analysis will be useful for directing training, intervention, and research efforts towards the most prevalent causal factors and incident types. Procedures and Definitions Data sources The primary sources of data for this analysis were files provided by MSHA containing information collected under Title 30 Code of Federal Regulations, Part 50. These files, commonly referred to as “Part 50 data”, are provided though MSHA’s Program Evaluation and Information Resources directorate. Two primary types of injuries were selected from the Part 50data: Fatalities (MSHA “degree of injury” code 1) and lost-time injuries, otherwise known as nonfatal with days lost (MSHA “degree of injury” codes 2 through 5). Lost-time injuries involve either actual days away from work or days of restricted activity or both. Fatality and lost-time injury incidence rates were calculated using the standard MSHA formula: Number of injuries per 200,000 employee-hours. Additional information on company sizes and mine ownership was provided by the Pennsylvania State University College of Earth and Mineral Sciences. Time span A five-year time span was selected for this study. More than a single year of safety experience is usually needed to capture a broad range of incident types. Many types of injuries, especially fatal injuries, can be extremely rare, and may be missed if too short a time span is selected. However, a time span that extends too far back may begin to suffer historical threats to validity. That is, incidents that occurred several years ago may be caused by hazards that have since been remedied or may be related to mining practices and conditions that no longer exist. A five-year span offers a practical compromise between these two concerns. Consequently, the MSHA Part 50 data files from 1993 through 1997 were used. The 1997 file was in “preliminary” form at the time of the study, so small variations from the final 1997 “close out” file can be expected. Based on past experience, we do not expect the close-out variations to have a significant impact on the findings.