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By George A. Savanick

Coal mine roof shales fracture preferentially at slickensided surfaces because of weak or nonexistent adhesion between two slickensided rock surfaces. The purpose of this Bureau of Mines research was to characterize chemically the thin film of smooth, glossy material that makes up the slickenside. This material was analyzed by electron spectroscopy and ion scattering spectrometry while in place on the rock surface and by standard methods of quantitative chemical analysis on concentrate removed from the rock. These analyses showed that the chemistry and mineralogy of the slickensides are similar to that of the adjacent shale.

Jan 1, 1974

By Andrew M. Leszcykowski

This report represents the first comprehensive accounting of lode mining sites in the Sheep Mountain mining district, Custer County, Idaho. Twenty-one mine and prospect locations have been added to the Bureau's Mineral Industry Location Subsystem (MILS) data base as a result of initial phases of a mineral appraisal of the River of No Return Wilderness; previously known locations were checked and the updated information added to the data base. The district's deposits are mainly confined to metasedimentary xenoliths in granodiorite and quartz monzonite. Those deposits in the north and west parts of the district are lead-silver-zinc replacement veins in dominantly calcareous facies; those in the southern part of the district are polymetallic fissure-veins containing pyrite, chalcopyrite, arsenopyrite, galena, and sphalerite hosted by micaceous schist and phyllite. The dominant structural trend in the southern part of the district is northwesterly and on strike with major deposits in the adjacent Seafoam mining district.

Jan 1, 1983

By Edmund Newton

The Haile mine has been the outstanding gold-mining operation and the largest single producer of gold in the Appalachian region. Gold was discovered at the Haile in 1827, previous to the present operation, production has been nearly $4,500,000 (gold at $20.67 per ounce.) from somewhat over a million tons of ore, with an average extraction of about 70 percent. The Haile property, now operated by Haile Gold Mines, Inc., is in the southern part of Lancaster County, South Carolina, 3-1/2 miles northeast of the town of Kershaw and 55 miles north of Columbia, the State capital. (See fig. 1.) The corporation has a lease and purchase contract on 1,805 acres, covering the present productive area. In addition, it holds lease contracts on 1,500 acres additional adjacent to this area.

Jan 1, 1940

By Mark P. Zaitsoff

The project involved design, construction, and testing of hydraulic models of culverts, decant and open channel spillways which are typical drainage structures used for protecting mine waste embankments. MSHA (The Mine Safety and Health Administration, U. S. Department of Labor) made a motion picture of the tests. Tests results and products in the forms of graphs, tables and films, demonstrate the principles and factors which govern the function and performance of the three types of drainage structures.

Jan 1, 1981

By Vinit Mody

The belt conveyor is one of the major pieces of equipment for transferring bulk material in mining operations. However, considerable amount of respirable dust may be generated whenever the bulk material is loaded, dumped, or transferred. This report identifies and evaluates various dust control technolgies applicable to belt conveyors, and describes how an integrated systems approach can reduce dust emissions at a transfer point. Phase I of the program consisted of literature search and a critical evaluation of various dust control technologies. The work established that a comprehensive approach to calculating exhaust volumes for dust collection system does not exist. The parameters that affect the wet dust suppression efficiency were also reviewed. Based on the Phase I work, bulk material handling system and dry dust collection or wet dust suppression systems were designed and installed at a number of transfer points in a limestone processing facility, a surface mine selected as a field test site. Field test data were used to determine the validity of various exhaust volume calculations at the different transfer points. The field test data also formed the basis for the evaluations of the relative effectiveness of commercially available and wet dust suppression systems in controlling respirable dust emissions.

Jan 1, 1984

By Mark S. Redfern, Kim M. Corneliusa, Christopher A. Hamrick, Sean Gallaghera

Coal miners often handle heavy electrical power cables, weighing up to 10 kg per meter. These cables are manually lifted and attached to the mine roof to prevent damage from mobile underground equipment. Data suggest that workers who commonly perform cable handling tasks experience a high rate of lost time back injuries. In this study, six male underground miners performed a total of 12 cable-hanging tasks in standing, stooping, and kneeling postures, during which kinematic and ground reaction force data were collected. Reductions in vertical work space were found to result in a linear increase in the peak moment experienced by the lumbarspine (p<0.05). In restricted postures, peak moments were not significantly different in stooping vs. kneeling postures (p>0.05). Average lumbopelvic flexion during the tasks was highest in stooping conditions, followed by standing and kneeling exertions (p<0.05). Implications of this data with respect to design of cable handling tasks are presented and discussed. Keywords: Biomechanics, posture, low back pain, restricted workspace, mining

By Robert F. Randolph

Real-world levels of attenuation from hearing protection devices are usually much lower than the rated values obtained under near-ideal circumstances. The shortfall is even more extreme for earplugs than it is for earmuffs, primarily because of the complicated process of fitting the plugs within the ear canal. This study examines the use of a commercially-available lubricant for hearing aids to determine whether it would facilitate improved fit and attenuation for earplugs. In this experiment, ten participants inserted earplugs with and without using the lubricant. Average attenuation was assessed with the Real-Ear-Attenuation-at-Threshold (REAT) technique, and showed over 5 dB improvement when the lubricant was used. Participants obtained an 85% mastery rate using the lubricant versus a 50% mastery rate without. These results indicate several possible applications for improved earplug performance in real-world settings where hazardous noise is unavoidable and effective hearing protection is necessary.

Jan 1, 2008

By M. M. Tilman

In a Bureau of Mines investigation to develop lead alloys with improved tensile strength and creep resistance, lead-base alloys containing cadmium and antimony in nominal 1-to-1 atomic ratios were melted in air, cast, and rolled into sheet to 90 percent reduction at temperatures varying from room temperature to 175° C. Tensile testing at room temperature and stress-rupture testing at 900±3° F were conducted on the as-rolled alloys. The best tensile properties were observed in an alloy of Pb-4.2 wt pct Cd-4.5 wt pct Sb which exhibited an average tensile strength of 7,270 psi with 36 percent elongation in 2 inches. An alloy of Pb-5.5 wt pct Cd-6.0 wt pct Sb had 100-hour stress-rupture values of approximately 2,100 psi and 1,000-hour values of approximately 1,700 psi.

Jan 1, 1969

To predict the spontaneous combustion potential of bituminous coals using a simple expression based on an easily acquired coal property. Background Approximately 20% of underground coal mine fires in the United States since 1978 have been attributed to spontaneous combustion. Spontaneous combustion fires in underground mines are most likely to occur in gob area; and are difficult to detect and to extinguish by direct fire fighting methods. Often, sections of the mine or the entire mine must be sealed for long periods, at a great economic loss to the mine operator, mine employees, and the surrounding community. It is conservatively estimated that the cost of scaling a large mine is about $50 million.

Jan 1, 1989

By Terry J. Close

A mineral resource survey of the 940-square-mile (2,434 km2) Hells Canyon study area, which includes Hells Canyon Wilderness, Snake and Rapid Wild and Scenic River&apos;s, and adjoining roadless lands in Oregon and Idaho, indicates the area is highly mineralized. Thirty-four lode deposits within the study area have resources totaling about 31 million tons (28 million t) containing copper, silver, zinc, gold, and lead; another 42 lodes, not sufficiently exposed to allow resource estimates, are believed to have mineral potential. The most important deposits are copper-, silver-, zinc-, gold-, and lead-bearing volcanogenic occurrences, followed by silver-and copper-bearing contact replacement (tactite) deposits; other lode occurrences are relatively unimportant. The most important placer deposits occur at Dry Diggins; placers along the Snake River are small and scattered. The study area has extensive deposits of limestone and sand and gravel; it has little potential for energy resources.

Jan 1, 1982

By J. B. Zadra

The use of activated carbon for extracting gold and silver from pregnant cyanide solution and pulp has been investigated many times. The primary advantage of this use of activated carbon is that .the dissolved values can be recovered from slimy ore pulps or from slime portions of ore without settling and thickening or filtering. The loaded carbon is removed from the barren pulp, and the pulp can then be discarded. Activated carbon has been used recently in treating gold ores containing very little soluble silver. When the carbon was loaded with a suitable amount of gold, the silver load was negligible. The remaining problems concerned the removal of the gold from the carbon, the recovery of the gold as bullion, and the reuse of the unloaded carbon. As described in a recent report, a method that solved these problems was developed. The gold-laden carbon was leached with caustic sodium sulfide solution and the gold simultaneously recovered by electrolysis. Both the carbon and the spent solution can be reused. That process was applicable to gold-laden carbon only. It was not applicable to carbon carrying silver, because sodium sulfide does not leach silver from carbon but "fixes" it. It has been necessary, therefore, to develop a modified process for the removal or desorption of both gold and silver from loaded carbon. This modi¬fied process permits the use of activated carbon for extracting both gold and silver from gold ores carrying enough silver to have economical interest or in which silver may be the predominating value.

Jan 1, 1952

By Stan Henning

The monthly summary of the climatological record for the demonstration mine is presented in Table 1. Tear normal temperatures occurred throughout the growing season. From May to October precipitation was more than normal except in June when it was 2.55 inches below normal. Corn and soybean plantings were delayed until June 2-7 because of wet field conditions. This is about one month later than normal for corn planting. Insect infestations were much less than those encountered in previous years. Cutworm activity was not noticed and alfalfa weevil infestation were small and patchy. Stalk rot in corn was a significant problem at harvest and resulted in much Milk lodging. The wet and generally overcast conditions of July, August and September were bend 10 beneficial al to certain plant disease organisms. For example, pumpkins planted in a small garden area at the demonstration mine did not ripen because of a powdery mildew resulting from overcast, wet conditions. Field operations and row crop plantings were greatly delayed by wet field conditions. It was difficult to plant by conventional tillage because the soil remained soft and sticky where the moldboard plow had been used. Plots in the no-tillage system could he planted before conventionally tilled plots could be traversed. Plant emergence and plant density at

Jan 1, 1982

By Michael C. Horn

The 61,470-acre Lick Creek Roadless Study Area is in the western Salmon River Mountains, centered 12 miles northeast from McCall, ID. U.S. Bureau of Mines personnel examined the roadless area in 1984. There is no recorded mineral production from the study area and no current mineral-related activity was observed. The roadless area is underlain by granitic rocks of the Idaho batholith. Pegmatite dikes and aplite dikes are present locally. Sampling indicates these rocks are not mineralized. No mineral resources were identified. INTRODUCTION This report describes the USBM (U.S. Bureau of Mines) portion of a cooperative study with the USGS (U.S. Geological Survey) to evaluate mineral resources and potential of federal lands recommended for wilderness, as required by The Wilderness Act of 1964. The USBM examines and evaluates individual mines, claims, prospects, and mineralized zones; USGS conducts broader geological, geochemical, and geophysical surveys. Such data helps Congress and other federal agencies make decisions affecting the use of public lands.

Jan 1, 1986

Recent Bureau of Mines research in earth grounding safety is documented in three separate papers. First, guidelines for the design of a 5- ohm borehole ground are presented. Next, an inexpensive practical means to construct a low-resistance bed in high-resistivity soil is described. Finally, a procedure that employs a commercial resistivity meter to measure shock potentials around grounded objects is explained step-by-step. These papers complement the material presented at an earlier technology transfer seminar and published as IC 8767.

Jan 1, 1985

By C. W. DeLong, L. L. Farnham, L. A. Stewart

This paper is one of a series covering mineral resources of the Nation . It describes briefly most of the known manganese deposits of eastern Arizona , which for the purpose of this report includes the counties of Navajo , Apache , Gila, Graham, Greenlee , Pinal , Pima , Santa Cruz , and Cochise . With few exceptions , these descriptions are the result of field examinations by the writers . Work on this paper was begun in May 1956 , and in the following 18 months 151 deposits were examined . The distribution of the deposits by counties is as follows : 1 in Navajo , and 1 in Apache , 37 in Gila , 4 in Graham, 13 in Greenlee , 25 in Pinal , 13 in Pima , 12 in Santa Cruz , and 45 in Cochise . In surveyed areas the locations of the deposits are described by section , township , and range and in unsurveyed areas , by approximate projections of these subdivisions . The township and range numbers refer to the Gila and Salt River base and meridian . The history, production, ownership , geologic setting , and mining methods used are discussed for most of the deposits that were visited . Probably , some occurrences have been overlooked , but all of the principal ones have been examined . Ore dressing studies were made of typical ores from several of the larger districts . The work was performed in the laboratory of the Bureau of Mines Tucson Metallurgy Research Laboratory . The results of these studies are given with the descriptions of the deposits from which the samples were taken .

Jan 1, 1961

By M. Leva

WITH the development of new processes for the production of synthetic liquid fuels, an extensive literature search was undertaken to uncover fundamental relationships between fluid and heat flows and the operating variables of new types of converters. Examination of published correlations revealed that considerable uncertainty existed in the correlation of the operating variables of such equipment with the pressure drops which could be expected through packed and fluidized systems; correlations proposed in the literature differed from each other frequently by as much as 75 to 100 percent. Because new processes, especially more recent modifications of the original Fischer-Tropsch process, must compete with old, firmly established processes on the basis of unit product cost, the pressure-drop correlations in the literature were considered to be too inaccurate for use in calculating the energy required to pass fluids through packed beds. The following study was begun in 1946 to develop correlations that would be suitable for the design of new equipment in which fluids are brought into contact with granular materials. To arrive at general relationships, systems were chosen that did not involve chemical reactions, and a, particular effort was made to give the correlations only in terms of quantities that are ordinarily available from general process and design specifications.

Jan 1, 1951

Horizontal holes are drilled underground into coalbeds to control methane flow from ribs and active face areas and to make gas pressure measurements in coalbeds. Gas pressure measurements are made by drilling the same hole incrementally. After each increment, the hole is filled with some type of packers and allowed to reach equilibrium before a gas pressure reading is taken. As the length of hole increases, more packers are required to effect a seal and obtain a reliable pressure measurement. Problems have been encountered in obtaining satisfactory packer seals due to the friable nature of the coalbed. New methods of packing the holes must be used. Therefore, this project was established to evaluate materials and develop a new technique in which a semiliquid and/ or rigid type grout could be placed in the hole to provide satisfactory sealing.

Jan 1, 1972

By Wils L. Cooley

The report covers tests and criteria for the establishment of safe grounding systems for coal mines. The work deals primarily with under-ground coal mines, but much is applicable to surface mines as well. Included is an extensive guide to grounding and bonding procedures for mine surface substations. Xit-Rods are evaluated and shown to deviate from manufacturer&apos;s claims. An analysis shows that very long cables are difficult to monitor using audio frequency ground-check techniques. A method is developed to detect failing cable splices without removing the cable from service. Simulation and measurement are compared for a technique to detect bad rail bonds, and an assessment is made of grounding techniques for dc face equipment.

Jan 1, 1979

By D. S. Burgess

This report summarizes the incidents that preceded the December 9, 1970, propane-air explosion in Port Hudson, Mo., and then attempts to establish the nature of the explosion from the ensuing events. Special emphasis is given to possible ignition sources, the distribution of flammable vapors, and the analysis of blast damage. Both near-and far-field damage indicated that this explosion may be attributed to the detonation of propane in air with an energy release equivalent to that from about 50 tons of detonating TNT.

Jan 1, 1973

By Bruce I. Thomas

Reconnaissance studies of beach sands along the eastern part of the Gulf of Alaska were conducted by the Bureau of Mines to determine if any of these coastal areas warranted investigations as possible sources of valuable minerals. Because of difficult access and limited transportation facilities only a minimum of sampling, surveying, and camping equipment is utilized to obtain spot samples from key areas as well as information indicating the location, size, and character of the deposits. Such data were obtained from beaches located along approximately 247 miles of the Gulf of Alaska coastline during parts of the 1957 and 1958 field seasons. A total of 201 3-inch-diameter auger holes, spaced roughly at 1 mile intervals, were bored by hand methods to depths ranging from 3 feet to 27 feet; also 33 shovel samples were collected from selected localities. Samples were reduced to a rough concentrate in the field by panning; the rough concentrates were shipped to the Bureau of Mines laboratory at Juneau for further concentration and for petrographic and chemical analyses. Particular attention was given to the heavy-mineral content of the concentrates, although the types and relative amounts of rock-forming minerals were also determined. The reconnaissance indicated that, generally, the valuable mineral content of the beach deposits was too low to be of further interest except in the vicinity of Yakutat and Lituya Bays where erratic but possibly significant concentrations of magnetite and/or ilmenite were found. At Yakutat, about 20 miles of beachline extending southeasterly from Ocean Cape, yielded samplas containing from 1 pound to over 300 pounds of iron and from a trace to over 100 pounds of titanium dioxide (TiO2) per cubic yard of beach material. However, the higher grade samples represented local concentrations of minor importance. The general tenor of the Yakutat beach, as indicated by the airthmetical average of 27 auger-hole samples, is about 35 pounds of iron and 20.5 pounds of titanium dioxide per cubic yard of beach material. Ilmenite is the predominant heavy mineral of the beach deposits in the vicinity of Lituya Bay, but it was found in concentrations only in limited areas near the

Jan 1, 1962