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By John R. Bartels

In laboratory testing, the Bureau of Mines established criteria by which common resin-grouted roof bolting systems can be evaluated and compared. Ultimate strength and stiffness were determined for nonten-sioned full-column, point-anchor, tensioned full-column, and debondable resin-grouted bolts, and for variations on full-column boltsn Bolt per-formances were compared using the performance of the 3/4-in full-column resin-grouted bolt as the standard. New and innovative systems can also be qualitatively compared against this standard. Since the medium into which a resin-grouted bolt is installed is one of the most important parameters affecting bolt performance, various host mediums were used in the testing: sandstone, concrete, simulated coal, simulated shale, and plaster. Bolt performances expected in other mediums can be inferred from the response patterns obtained in these mediums. Results indicate several functional differences among bolt types. Where resistance to shear is important, point-anchor bolts may outperform nontensioned full-column bolts at a lower cost. In medium-to soft-strength rock, tensioned full-column bolts perform best. Also, varying the resin-steel ratio seems to have little effect on the properties of a full-column bolt, when proper resin mixing is ensured.

Jan 1, 1985

By John H. Soule

"Although known since 1902, the Capitan iron deposits have not been mined, mainly because of the low grade of the ore. Only a small amount of exploratory work has been done since the discovery. C. H. Johnson, district engineer of the Bureau of Mines in New Mexico in 1942-45, visited the property; as a result, preliminary sampling of the property was done in 1943.3/ Owing to the results of this preliminary work, an extensive development program by wagon drilling was planned and executed early in 1944.4/ Equipment available at that time was limited in the depths that could be reached; and, as geologic studies indicated the possibility that other limestone beds below the surface might have been replaced by iron minerals, a supplementary development program by churn drilling to reach greater depths was prosecuted in late 1947 and early 1948, with the author as project engineer.The following sections note the location and accessibility of the deposits and mention the physical features, climate, labor and living conditions. Property and ownership are outlined, the history and production of the property stated briefly, and the ore deposits are described. The work done by the Bureau of Mines is explained and supported with maps, sections, and assay logs.From March 1, 1944, to June 1, 1944, 179 wagon-drill holes totaling 3,490 feet and 4 test pits totaling 75 feet were completed, and from November 1947 to February 1948 seven churn-drill holes totaling 2,488 feet were drilled and sampled. Metallurgical tests are summarized and referenced.With respect to this report, special acknowledgment is due to J. H. Hedges, chief, Tuscon, Ariz., Branch, Mining Division, and to W. R. Storms, engineer in-charge of the Silver City, N. Mex., field office. Acknowledgment also is due to J. Bruce Clemmer, chief, Tuscon Branch, Metallurgical Division, for analyses done in the last phase of this project, and to Dr. Vincent Kelley of the Federal Geological Survey for his cooperation during this work.The Capitan iron deposits are in secs. 10, 11, 13, 14, and 15, T. 8 S., R. 14 E., central Lincoln County, N. Mex., as shown on figures 1 and 2. The only known large deposit upon which the Bureau did development work lies around the common corner of secs. 10, 11, 14, and 15, as shown in figures 2 and 3, and just southwest of and in the foothills of the Capitan Mountains. This range of mountains trends east and west. The elevation of the highest peak is 10,205 feet.The deposits are reached by traveling on State Highway 48 from Capitan north for 4 miles, to a point just inside the Lincoln National Forest fence and thence due east over a poor dirt road for 1.2 miles. Just over a small wooden bridge, the left-fork is taken, and the poor road is followed to the deposits, a further distance of 1.1 miles (see fig. 1). This road follows the fence to and through the Davis ranch. All the roads from Capitan to the deposits are dirt roads but are impassable only for short periods during and after heavy rain or snow."

Aug 1, 1949

This publication summarizes the in-house and contract research projects programmed for fiscal year 1984 by the Bureau of Mines under its Conservation and Development activity. The document provides a mechanism for interested parties to gain insight into projects of the Bureau's Conservation and Development research program. The objective of the Conservation and Development Program is to provide the technological advances needed to stimulate the mining of domestic deposits containing critical, strategic, and other essential minerals in compliance with existing regulations and at costs sufficiently low to be competitive in world markets. Research efforts are directed toward improving the fundamental understanding of processes and procedures involved in the production of minerals. The overall goals will be accomplished by investigating alternative mining methods to increase domestic production of critical and strategic minerals from low-grade deposits; expanding the technology for the economic and efficient extraction of minerals consistent with cost-effective compliance with environmental regulations; and advancing the technologies needed to insure an adequate supply of coal.

Jan 1, 1984

By J. E. Tress

The Bureau of Mines prepared submicron tungsten powder by reducing tungsten hexachloride with hydrogen. The particle diameters of the resulting tungsten powders ranged from 0.015 to 0.046 micron. Within the limits of the variables investigated, no clear-cut correlation was found between process conditions and final size of the powder. Oxygen was the major contaminant in the product; being present both as an adsorbed gas and as suboxides of tungsten. Studies showed that the powder yielded compacts of approximately 45 per-cent of theoretical density when compacted mechanically. Low-temperature sintering produced more rapid densification in these compacts than in compacts prepared from conventional powders. Adding up to 20 percent ultrafine powder to conventional tungsten powder caused an increase in density upon compaction with maximum densification occurring at approximately 12 percent ultrafine powder.

Jan 1, 1966

By M. J. Dailey

This paper is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The property of the Silver King Coalition Mines Co. is situated in the western past of the Park City mining district, Utah, about 1 ½ miles southwest of the town of Park City, The elevation at the collar of the main shaft is 8,137 feet above sea-level.

Jan 1, 1930

By Robert E. Barieau

This report gives the principles of the method used by the Helium Research Center of the Bureau of Mines when solving nonlinear-regression problems and contains the mathematical equations necessary to accomplish the following objectives: the evaluation of the parameters in such a way that the sum of the weighted squares of the residuals of an experimental observable is a true minimum, regardless of the functional relationship between the variables and these parameters; and the evaluation of all variances and covariances of the parameters by means of the usual approximation of the law for the propagation of errors.

Jan 1, 1967

By C. L. Brown

Coal has been transported by belt conveyors in mines for many years; however, only since the beginning of the general mechanization period have complete transportation system of this type been employed. Aside from my complete belt-conveyor transportation systems, belt conveyors are frequently used in conjunction with other transportation. Many early installations, for the most part, were made without standards as a guide. As a result, some States have outlined certain requirements based more or less on experience following mine fires. Correlation of these regulations should result in more uniformity in connection with standardization of regulations. The National Electrical manufacturers Association has published standards for mining-belt-conveyor installations2/ that should be helpful to the coal-mining industry generally. Bureau of Mines Schedule 2F3/ requires certain controls for permissible-belt- conveyor drives, and similar requirements are listed in Bureau of Mines bulletin 514.4/ Committees of the American Mining Congress have prepared much valuable information concerning operation of belt conveyors, and a subcommittee on fire-resistant belting has been active. 5/

Jan 1, 1956

By D. G. Kesterkel

Low-melting thoriurnrbase binary alloys or metal solutions were prepared by two different techniques involving the electrolysis of ThO2 dissolved in fluoride melts. Experiments were performed at 950° to 1,250° C using electrolytes containing ThF4 and various alkali and alkaline earth fluorides. In the first method, electroreduction of ThO2 and deposition of thorium on a nickel or iron cathode formed a molten alloy that dripped off and collected on the bottom of the cell, or in a tungsten cup. An electrocodeposition technique was used to prepare thorium-base alloys or solutions containing nickel, iron, chromium, or manganese. Electrolytic reduction of the component metal oxides and simultaneous deposition of the two metals on a tungsten cathode yielded a liquid alloy product. Complementary experiments were performed on the fused fluoride electrowinning of dendritic thorium from Th02 at 1,075° to 1,200° C in which thorium crystals were recovered and arc-melted into buttons. Major contaminants were aluminum, carbon, copper, iron, oxygen, and silicon, totaling 0.2 percent.

Jan 1, 1966

A revolutionary development in blasting materials has occurred in recent years. Ammonium nitrate, sensitized by the addition of a small percentage of No. (class) 2 diesel fuel or other suitable petroleum product, has been adopted as a low-cost, efficient blasting agent2 in a wide variety of mining, quarrying, and heavy construction operations. Moreover, the ready availability of the component supplies throughout the Nation, together with the ease of formulating them into effective blasting agents, has made it possible for the blaster himself to prepare the mixes at the site of use. Recently, most established explosives manufacturers have begun supplying premixed AN-FO (ammonium nitrate-fuel oil) or a comparable product to various mining operations. However, many individuals and small business establishments are marketing premixed products prepared in facilities that are often poorly constructed and poorly located. Although these blasting agents have partly or wholly displaced explosives such as dynamites in many applications, there are some blasting operations in which the fuel-sensitized ammonium nitrate agents do not appear to be well adapted. As long as the hazards they present are clearly understood and respected, ammonium nitrate-based blasting agents have important safety characteristics when prepared under competent factory control or field-mixed under equivalent close control. This publication attempts to summarize the knowledge of those hazards and to incorporate practical ways to cope with them.

Jan 1, 1963

By A. Adams

The Bureau of Mines determined the composition of the vapors liberated during thermal decomposition of aluminium nitrate nonahydrate. Small samples were heated from room temperature to 5500 C with initial heating rates from 500 to 2000 C/min. Gases were rapidly swept away from the heated chamber with Ar and subjected to immediate analysis in order to minimize reaction between the components. In addition to H20, four N-containing compounds were identified: HN03, N02, NO, and N20. Nz could not be determined in the presence of the nitrogen oxides, and at-tempted separation from the oxides led to the formation of more nitrogen. Relative amounts of each component were found to vary over a period of time; however, total amounts measured with different heating rates were reasonably constant and were typically as follows: 84.2 pct HN03, 7.1 pct N02, 4.3 pct NO, and 4.2 pct N20. HN03 and NO were determined from chemical reactions with a permanganate solution, N20 was measured with a mass spectrometer, and NO2 was measured with a spectro-photometer. Details of the methods used are described. Since NO2 and NO can readily be converted to HN03, about 96 pct of the N from the decomposition can be recovered as HN03

Jan 1, 1987

By N. E. Hanna

An important goal in the development of coal mining explosives has been to improve their safety characteristics through suitable formulation. In the United States no systematic effort to establish factors influencing the incendivity to firedamp and to coal dust of explosives through research was made until the last decade. In consequence, American permissible explosives underwent only very slight modifications and many remained substantially the same as in the early years. As part of a long range program for increasing the safety of permissible explosives, the Bureau of Mines undertook to determine how the amounts and particle sizes of the principal constituents of these explosives affect their incendivity. It was found that an increase in the relative amount of sodium chloride and a decrease in its particle size significantly decreased the incendivity of our permissible explosives to firedamp (7-9).6 This is in agreement with findings reported by Dolan (4) for compositions of nitroglycerin and salt. One important result of the work at the Bruceton station has been the recent introduction of salt-formulated permissibles by several explosives manufacturers. This paper describes a statistically designed experiment for studying the effects of the particle size of ammonium nitrate and the type of carbonaceous materials used on the incendivity of permissible explosives. Interest in these particular effects goes back as far as the first formulations of coal mine explosives, around 1910 in the United States and even earlier in Great Britain and other countries. Although it is well established that fine

Jan 1, 1961

By C. L. Brown

The frequency of mine fires during recent years, with an apparent increase in recent months, has focused attention on the necessity of reducing this hazard by every means possible. Investigation reports are available on 51 mine fires of electrical origin between August 15, 1949, and August 16, 1954. Nine other fires in the same period were suspected as being of electrical origin. Every mine fire is a potential hazard to underground workmen; it is remarkable that only six lives were lost as a result of these fires, since the injury list was very high. Modern mining methods, with increased power demands and extended distribution systems underground, involve greater electrical hazards and possibilities of costly production delays as a result of inadequate electrical service. Improvements in electric-power-distribution facilities in many underground coal mines is desirable. The purpose of this paper is to show the need for this improvement as revealed by studies and investigations of electric-power-distribution systems representative of those in a large number of coal mines.

Jan 1, 1955

By Elaine T. Cullen

Underground mining, like many high-risk industries, is facing a crisis in the near future. This industry has traditionally relied on a master-apprentice relationship to train new workers, but experienced miners are retiring in large numbers, leaving few "masters" to properly train their replacements. With a recent resurgence in mining, many new miners are entering the workforce each day. The rise in the number of inexperienced workers has implications for worker safety in an industry in which one mistake can blow up the entire workplace. The explosion in the Darby Mine in May 2006 that killed five miners illustrates what can happen in hazardous environments such as underground mines. The Health Communications Team at the National Institute for Occupational Safety and Health Spokane Research Laboratory was asked to address this problem by developing new training and safety awareness materials to promote safe flame cutting and welding practices. This article describes how occupational ethnographic techniques provided insights needed for "new product development." The result of this work was a national initiative to raise awareness and to protect underground coal miners from the dangers of flame cutting and welding in an environment filled with solid fuel and methane (natural gas). Although this project was initially designed for the mining industry, the approach and lessons learned are applicable to any high-risk industry and should be of interest to other social marketing or occupational safety and health professionals.

Jan 1, 2009

By E. W. Parsons

Permanent support of the back is an important economic factor in maintaining a tunnel or other underground opening in condition to render the service for which it was driven. Timber has been most commonly used for support in tunneling and drifting because of its strength and ease of installation. Even when treated for decay, however, timber is subject to deterioration and, over a long period of time, should not be considered a permanent support. Concrete support or lining is permanent and has been used in tunnels of every size for many years but has been almost exclusively cast in place, a difficult, costly process. This report deals with the design and installation of precast concrete supports to combine the best features of both methods.

Jan 1, 1958

By D. W. Frommer, M. M. Fine

"INTRODUCTION Laboratory mineral-dressing investigations covered by this report show that ores from Montgomery County, Ark., and Morgan County, Mo., are potential sources of barite and zinc. Fine grinding and froth flotation yielded drilling-grade barite from the former and chemical-grade barite and zinc concentrates from the latter.Samples from these deposits were subjected to a laboratory investigation to develop an economic and feasible treatment. The Arkansas ore, submitted by the Husky Refining Co., consisted of an intimate mixture of the economic mineral and quartz. Fine grinding and fatty acid flotation were utilized to effect a good recovery of a drilling-grade product. The other was a zinc-barite ore submitted by the Rocky Ford Mining Co., Stover, Mo. There was no problem in the recovery of zinc (most of which occurred as sphalerite), but the recovery of barite by flotation was complicated by the presence of gangue carbonates. Ultimately, an excellent recovery of barite was achieved with a relatively new type of flotation promoter, petroleum sulfonate.In recent years, barite has become one of the major industrial minerals as an essential ingredient in heavy drilling fluids, pigments, and chemicals. New sources of this important commodity are always interesting; thus, it is the purpose of this report to present information that may permit commercial exploitation of two deposits not in production."

May 1, 1952

By A. Wahab Khair, N. P. Reddy

"Abstract. This paper attempts to characterize coal breakage due to the action of a continuous miner. Coal blocks with an approximate dimension of 45.7 cm x 38.1 cm x 15.2 cm (18 in. x 15 in. x 6 in.) were first subjected to confining pressures equivalent to in-situ conditions. Then the blocks were cut along the face/butt cleat direction by the cutting head of a specially designed unique automated rotary coal cutting simulator (ARCCS), simulating the action of the continuous miner in underground coal mining. During the tests under a particular set of in-sit and operating parameters a number of other para¬meters such as 1) penetration of bit into coal, 2) penetration resistance (thrust and cutting pressures), 3) rotating velocity of cutting head, and 4) acoustic emission activity in the coal block were monitored. After each cutting cycle the fractured surfaces were photographed and a velocity survey was conducted by using a sonic technique. At the end of each experiment, the coal fragments were collected in bags using a vacuum cleaner. These fragments were then sieved for size distribution analysis.INTRODUCTIONThe Federal Coal Mine Health and Safety Act of 1969 was enacted to emphasize to coal operators that the airborne respirable dust should not exceed 2 mg/m3, thus reducing the incidence of coal workers pneumoconiosis.Dust control techniques such as conventional water sprays and dust collectors are only partially effective and require additional equipment expenditures. A more authentic approach would be to reduce respirable dust at the source the continuous mining machine cutting head, where the fragmentation process occurs. Improving the fragmentation process by characterizing the coal breakage will not only reduce respirable dust at the face, but it will also decrease the amount of respirable dust that is liberated during the secondary handling.Fragmentation of coal can be expressed as a function of three major groups of parameters; namely, 1) coal properties, 2) in-situ conditions and 3) operating parameters. This paper deals with the characterization of coal breakage along both face/butt cleat direction as a function of machine operating parameters such as rate of advance, angle of attack, bit configuration, bit lacing (spacing and pattern) and bit speed at various equivalent in-situ pressures."

Mar 1, 1989

By C. E. Wicks, J. E. Tress, F. E. Block

The Bureau of Mines investigated the effects of gamma radiation on materials and chemical reactions to obtain information that could be of value in modern metallurgical practices . Various combinations of metals and their ores and compounds were irradiated in attempts to effect reactions that might be applicable in the extraction and separation of metal values from minerals and The types of reactions studied included complexing of salts , decomposition of hydrated salts , metal chlorination reactions , leaching of ores and minerals , halogen exchange , and various reducing reactions . All irradiations were performed at the Materials Testing Reactor Gamma Facility of the U.S. Atomic Energy Commission at Idaho Falls , Idaho . Spent fuel elements were utilized as the source of the gamma radiation . Some irradiation - induced changes , ranging from mere color change to participation in chemical reactions , were noted . The greatest value of these investigations , however , was the experience acquired , which should be valuable in future explorations of similar nature .

Jan 1, 1964

By R. R. Schehl

The Bureau of Mines has developed a quantitative Analysis for pyrite in coal by X-ray diffraction that can be accomplished in little more than 1 hour. To minimize the sample analysis time, data processing has been completely computerized with pertinent output information displayed on a VR12 cathode-ray tube display. Use of this computerized system is not only advantageous during the experimental stages of the pyrite analysis project but would also be essential if the X-ray diffraction procedure is accepted as a standard method of analysis.

Jan 1, 1973

By R. V. Mrazek

The heat of formation of vanadium trichloride was determined at 298.15° K. Measurements were made in a solution calorimeter in which an aqueous hydrochloric acid-potassium dichromate solvent was employed. Data are presented for the heats of solution of vanadium trichloride and the vanadium trioxide "backup" compound, and for appropriate dilution reactions needed to preserve stoichiometry. The resulting heat of formation of vanadium trichioride (VCI3) at 298.15° K was found to be ?H°298.15° K = -138.89 ±0.37 kcal/g mole.

Jan 1, 1968

By K. E. Stanfield

The oil yields of sections of Green River oil shale in Colorado, Utah, and Wyoming are presented as part of a continuing project to determine oil-shale reserves in the United States. Oil-yield logs, based upon analyses obtained from 1945 through 1952, are presented to show the thickness and richness of 202 sections of Green River oil shale. The logs are based on analyses of approximately 20,500 samples, representing 179,000 feet of shale, which were made by the Bureau of Mines, and upon analyses, representing approximately 26,000 feet of shale, which were made by other agencies. The samples consisted of cores from a Bureau of Mines coring program in U. S. Naval Oil-Shale Reserve 1, Garfield County, Colo., and cores, drill cuttings, and channel samples provided by other agencies, chiefly oil companies. Most of the samples of oil shale from Utah and Wyoming were derived from oil-well drilling operations. As a result, the oil-shale sections were widely scattered and were not extensive or reliable enough to be representative of the significant deposits of Green River oil shale in these States. The oil-shale sections for Colorado, however, were more comprehensive, and a number of the sections were used in a previous report as a basis for estimating oil-shale reserves in Colorado. The present report does not give estimates of oil-shale reserves but is limited to presentation of oil-shale analyses that may be used for future reserve estimates. Other sections of Green River oil shale are being analyzed, and the results will be published in subsequent reports.

Jan 1, 1954