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By Eugene H. Skinner

The 7-mile Flathead Tunnel, located in the central Salish Mountains of northwestern Montana, was constructed between 1966 and 1969, With the contract awarded April 19, 1966, drill and blast tunnel excavation began September 30, 1966, and was completed June 21, 1968, in 488 tunnel-driving days, Peak advance was 66 feet per day. On June 27, 1969, all tunnel concrete lining was completed. Average wall and arch concrete placing rates exceeded 1,700 cubic yards daily, with nearly half of the concrete placed during a severe winter season. Major cost savings in concrete tunnel lining were achieved through a value engineering clause in the contract. Achieving consistent results and high rates of placement in concrete lining ranked equal to ground control in overall tunnel problems. Ground control problems exceeded expectations and were of continual concern throughout excavation, One support collapse in the tunnel and one portal slide condition developed during construction. Critical surface geologic exposures were largely obscured; only a portion could be accurately projected underground, An instrumentation program to gather basic data on rock defamation near the heading face for support purposes was a pioneering effort. The Flathead Tunnel was placed in service on November 7, 1970.

Jan 1, 1974

By G. L. Oldright

As sponge iron is much like porous, coarse sand, it is a tempting material to use in place of coarse scrap iron as a precipitant of metals, for scrap iron is relatively awkward to handle and exposes only a small amount of surface to pregnant solutions. The results of the experiments described in this bulletin are largely a record of the behavior of sponge iron as a precipitant of lead and copper under laboratory conditions comparable to those that would obtain in a commercial plant were it attempted to secure the maximum contact of surface between solution and precipitant. Physically, the study is largely one of the rates of diffusion of the metal ions in the solutions and through the metallic coatings surrounding the sponge iron particles. The practical objectives are to remove completely the valuable metals from solution and at the same time to obtain a precipitate of good grade. In order to fulfill this latter requirement, the precipitant should be almost completely consumed. These practical ends are usually secured by having the two substances involved pass each other counter-currently-that is, in such a manner as to have the strongest precipitant in contact with the most impoverished solution, and vice versa. EXPERIMENTS WITH LEAD SOLUTIONS In nearly all of the schemes involving the leaching of lead from its ores the metal has been put into solution as the chloride, and fairly concentrated liquors have been employed. The solubility of lead under such conditions is comparatively small at best; the hot pregnant liquors from which the metal is to be precipitated are then made nearly saturated with respect to lead, and only a very small amount of acid is used. Therefore it was not as necessary to learn the behavior of the sponge iron in precipitating lead from solutions of widely differing composition as to learn under what conditions, and with what mechanisms, this precipitation might be carried out most readily.

Jan 1, 1928

By G. H. Bennett

A field experiment was performed in a production unit of an operating copper room and pillar mine to compare the support capabilities provided by resin and mechanical roof bolts. Resin and mechanical roof bolts were alternately installed in eight intersections in a single entry. Rock mechanics instrumentation was installed to measure roof sag, bed separation, convergence, bolt pullout, torque, and strain. Bolt cost and installation time are included. Two analyses of the test were made. The analysis of the rock mechanics data showed there was no definite difference between the two bolting systems. From a broader analysis on a mine-wide basis it was concluded that resin bolts gave better support. A critical view of the experiment is given in the appendix.

Jan 1, 1974

By R. B. Tippin

To study continuous operation of the heavy liquid separation (HLS) of minerals, the Bureau of Mines concentrated spodumene from a typical ore. The studies included heavy liquid concentration, removal of the heavy liquid from the mineral products, and recovery of the heavy liquid for reuse. The research program examined the influence of feed moisture, steam consumption, stripping time, and condition of steam. Operation of multiple cyclones in series resulted in spodumene concentrates assaying 92 to 95 percent spodumene and indicated mineral recoveries of 86 to 89 percent. Continuous filtration and steam stripping produced mineral products containing less than I pound of heavy liquid tetrabromoethane (TBE) per ton of material. Problems unique to this process are discussed, including heavy liquid properties and viscosity, toxicity, material handling hazards, and safety precautions.

Jan 1, 1970

Underground coal mine tracked vehicles have been studied to determine the state of the art and how brakes might be added to the coal haulage cars. Specific areas of interest are: brake sys terns, couplers, car trucks and car handling procedures. Problems related to adding brakes to the haulage cars appear to be: the limited amount of room to mount the brakes on the cars, brake line connection between rotary dump cars, achieving desirable braking characteristics without over complicating the system and keeping the installation cost to a reasonable figure. This document combines the information contained in the first issue of the "State-of -the-Art of Underground Coal Mine Tracked Vehicle Brake Systems," BRL Report No. 6080, with that contained in a subsequent monthly report.

Jan 1, 1973

By J. W. Thompson, M. N. RICH

That there is wide interest in the preparation and properties of metallic zirconium and its salts is indicated by the many articles recently published in scientific and technical journals and the many patents issued. The compounds of zirconium have numerous important uses and more uses will doubtless be found. In the course of the special work on rare metals that were of military importance during the war, the authors of this bulletin were detailed to the Golden mining experiment station of the Bureau of Mines to prepare metallic zirconium and to investigate its properties. A number of investigations in recent years have indicated that sintered or coherent zirconium metal is very resistive to acids; that it can be used for electrodes, and it probably will find metallurgical uses. A steel containing zirconium has been proposed for use in armor plate and automobile parts, and nickel-zirconium alloys have been suggested for high-speed cutting tools and for cutlery. Numerous articles in scientific journals have recommended the use of zirconium oxide as a refractory, an abrasive, a pigment in paints, and as an opaquing agent in enamel ware. The salts have been used in the textile industry' as a mordant and also for weighting silk. When the authors began their investigation, they found it necessary to collect all of the available literature on the general subject of zirconium and its compounds. Pure salts could not be obtained on the market, and in order to get these, as a preliminary step to the preparation of the metal, the literature had to be classified and the methods of preparing the salts investigated. Also, there was much difficulty at first in making satisfactory analyses, and this phase of the work received careful attention. As it was necessary to begin with a historical review of the literature, such a review is given as Part I of this report, and a bibliography is included as Part IV. References to the numbered items in this bibliography are made throughout the text, the usual footnote references being omitted. Analyses of the products and conclusions as to their purity are given under the descriptions of methods of preparation. A table showing the properties of the amorphous metal, and another showing the properties of the coherent metal, will be found under appropriate headings in Part II. No attempt has been made in the historical review to discuss fully all the published information about zirconium and its compounds, but only such material has been assembled as has a direct bearing upon the present work. Considerable difficulty was experienced in collecting this material because of the confusion of terms by various authors who perhaps did not thoroughly understand the chemistry of zirconium.

Jan 1, 1921

By P. A. Cox

The purpose of the initial research performed under this contract was to determine the margins of safety in explosion-proof (XP) enclosures, which were designed and certified according to the current schedule (Schedule 2G). Results from this work provide baseline data on the current schedule, from which a new schedule can be formulated to give equal or greater levels of safety. Results and discoveries in the initial work led to an expansion of the contract to cover, additionally, weld quality in enclosure fabrication, reliability of enclosures with windows and lenses, and performance tests for enclosure qualification. Finite element calculations and hydrostatic tests revealed wide variations in the margins of safety in the enclosures studied; however, only one enclosure had a safety factor which was less than one. Results from a weld quality survey led to the recommendation of AWS Welding Standard D14.4 for the fabrication of XP enclosures. Based on other work, accelerated aging tests were recommended for qualifying plastics and adhesives that are used in some enclosures, and a Structural Performance Test was developed to test enclosure strength for a minimum static pressure of 150 psig.

Jan 1, 1982

The number of railroad coal cars (open top hoppers), dominated rail car orders and deliveries in 1975 according to announcements made February 11, by the Association of American Railroads and the American Railway Car Institute. Acting to keep ahead of increased coal production, the railroads installed 21,748 new coal cars in 1975, the most since 1957. The 1975 installation resulted in a net increase of 6,560 coal cars and an overall gain of 4.5 percent in the total capacity of the hopper car fleet. With most of the new coal cars going into unit train service --where car utilization is greatest --the railroads actual coal-carrying capacity was increased far more than 4.5 percent. The AAR estimated that unit train operations now move 50 percent of all rail-hauled coal compared to only 42 percent 2 years ago. COBALT - The Societe Miniere de Tenke Fungurume (SMTF) copper-cobalt project in Zaire reportedly was suspended in January for an indefenite length of time. According to officials, the deferment resulted from a number of adverse factors, one of which was exceptional increases in capital costs. The project was scheduled for completion in early 1978, with an eventual production of 14.3 million pounds of cobalt per year. Reserves of cobalt were reported to be 505 million pounds. SMTF is a consortium and includes American, British, French, Japanese, and Zairian interests.

Jan 1, 1976

By D. Christofferson

This final report documents the cooperative efforts of the Engineered Systems Division and the Mining Equipment Division of FMC Corporation during performance of Bureau of Mines Contract H0252091. Improved operator compartments incorporating overhead canopies, logical arrangements of controls, and design features offering greater operator comfort were developed and retrofitted to the FMC 320A roof bolter and 6L shuttle care The vehicles were evaluated in underground operations at separate mine sites. The successful evaluation has resulted in incorporation of the designs as standard features of the 320A roof bolter, and the 5L, 6L, and 10L shuttle cars.

Jan 1, 1978

By Frank E. Cash

The Bureau of Mines in its safety work has for a number of years advocated and recommended the use of permissible portable electric cap lamps for use in all mines. In the course of time required for the evolution from an unsatisfactory to an efficient and safe light, but encouraging increase in their use has been experienced in Alabama. As early as 1916, small installations of these safer lamps were made or an experimental basis by several operating companies, and the first complete mine installation eras made at the Virginia mine of the Gulf States Steel Co., July 1, 1918. From the experiments in 1316 and the complete equipment of the first mine in 1918 gradual progress has been made until there are now 30 installations with 10 operating companies; as a result 20 mines have been put entirely and 5 partly on, closed lights, and 3 companies equip their engineering departments; two installations of closed lights are maintained by other companies for emergency use. One of the mines partly on the electric cap lamp is an ore mine - the only one in Alabama (and one of the very few in the United States) that uses closed lights. ACKNOWLEDGEMENTS The full cooperation of operating officials, lapmen, and lamp representatives was given in the collection of the data in this report, and is hereby acknowledged.

Jan 1, 1928

By Alvin Schallis

Of all the uses for dolomite that depend on its magnesia content, perhaps the most important is its use in basic refractories. The quantities of dolomite (including both that used as crude and that calcined before use) sold or used for refractory purposes by producers in the United States for 1920-41, inclusive, are shown in figure 1. As can be seen from the chart, the utilization of dolomite as a basic refractory is far from new; it was, in fact, the first basic refractory used extensively in open-hearth steel furnaces. After large deposits of magnesite were opened in Austria-Hungary, the use of dolomite in the open hearth declined somewhat, only to be actively revived during the World War of 1914 to 1918, when supplies from Austria were shut off. The use of dolomite as a refractory in the steel industry again declined slightly for a brief period after the Armistice, but subsequently its use has tended steadily to increase, latest statistics indicating that more dead-burned dolomite is used per ton of open-hearth steel now than during the World War of 1914 to 1918. Despite fluctuations in consumption, dolomite has continued to be by far the most widely used basic refractory material. The following table, showing the quantities of basic refractories consumed in the manufacture of steel, the principal outlet, indicates the relative importance of dolomite. The chief reason for the widespread use of dolomite as a basic refractory is its relatively low cost. Its abundance and the proximity of the deposits to the steel industry (see fig. 2) afford every incentive to enhance the desirable physical properties of dolomite refractories and to ameliorate certain of their less desirable characteristics. The present emergency, with its huge demands upon the steel industry, has lent further impetus to the work of improving dolomite refractories.

Jan 1, 1942

This Bureau of Mines report and its companion report (Information Circular 9142) have been prepared to assist in the preparation of prefeasibility type estimates for capital and operating costs of beneficiation of various types of mineral occurrences using current technology. The handbook provides a convenient costing procedure based on the summation of the costs for the unit processes required in any particular mining or mineral processing operation. The costing handbook consists of a series of costing sections, each corresponding to a specific mineral processing unit process. Contained within each section is the methodology to estimate either the capital or operating cost for that unit process. The unit process sections may be used to generate, in January 1984 dollars, costs through the use of either costing curves or formulae representing the prevailing technology. The mineral processing handbook includes individual cost estimation sections for unit operations associated with comminution, beneficiation, solid-liquid separation, hydrometallurgy, and special applications as well as infrastructure and plant general and administrative costs. When using this system for estimating cost data for a mineral processing facility or for checking or verifying processing costs from an existing facility, a minimum amount of background information is necessary.

Jan 1, 1987

By Hewitt Wilson

A review is given of the nomenclature, sources, imports, statistics, common methods of preparation, and testing of mineral pigments. A description of the Deer Park-Spokane colored-clay district and the laboratory methods of preparation of these colored clays, others, and siennas follows. The mineral pigments were prepared by washing or grinding the original material as received and by calcination of the yellow ocher and brown sienna with and without manganese dioxide to produce red, brown, and black colors. These prepared powders were tested for fineness, oil absorption, and color as compared with well-known brands of commercial pigments. Similar tests were made with several basalt red clays occurring in the neighborhood of Salem, Oreg., and Kalama, Eatonville, and Clay City, Wash. The color particularly was studied, since this property is the most important commercial characteristic of the minerals. PURPOSE OF INVESTIGATION Since the development of the clay industry in the Pacific Northwest, some curiosity and interest have been aroused by the red and yellow clay or ocherouslike material that has often been found associated with the commercial clay deposits. These include the red and yellow "paint pots" near Deer Park and Spokane in eastern Washington, a red clay at Clay City, another close to Eatonville in western Washington, and red basalt earths near Salem, Oreg., and along the Columbia River near Kalama, Wash. Several companies have been organized to produce pigment colors from two of these deposits but have either discontinued or never started operations.

Jan 1, 1929

By Michael L. Clar

The U.S. Bureau of Mines contracted a study to determine the feasibility of water diversion and overburden dewatering for underground coal mines in the Appalachian Region. All relevant published literature pertaining to the occurrence and control of surface and groundwater in underground coal mines was reviewed and organized into a bibliography. The impacts of mine water with respect to health and safety, production, environment, and costs were assessed. Sources of water inflow into underground mines were described. A summary description and evaluation of techniques that can be used to reduce the amount of water entering underground coal mines was prepared. A review of engineering practices currently used by operating coal mines in the Appalachian region to prevent the movement of ground and surface water into active coal workings was conducted. Major emphasis was placed on the identification of the geologic and hydrologic con¬dition of the site, onsite inspection of the methods used and an evaluation of their technical and cost effectiveness.

Jan 1, 1981

By John B. Knaebel

This paper is one of a series being prepared by the Bureau of Mines on mining methods and costs at various mines in the United States, Canada, and Mexico, and is a description of practice at the Edwards mine of the St. Joseph Lead Co. ACKNOWLEDGMENTS The cooperation and assistance of the officials of the St. Joseph Lead Co. in permitting publication of this paper and providing every facility for its preparation are gratefully acknowledged. Especial thanks are extended R. J. Mechin, manager, R. F. Mitchell, mine captain, and J. S. Brown, geologist, for their generous aid, and the assistance of W. H, Weijola, mine engineer in assembling some of the illustrations is deeply appreciated, The helpful suggestions of C. F. Jackson, principal mining engineer, U. S. Bureau of Mines, are gratefully acknowledged.

Jan 1, 1932

By D. Harrington

Coal mines and mining-, as well as metal and nonmetallic mines and min¬ing, are not inherently unsafe, although mining people think they are and would like to have everyone else think so. It is now being demonstrated that mines can be operated with essentially as much safety as any other major industrial enterprise; but most mining people, including workers as well as officials, have been slow to realize or admit this. In the past, and with most people even at present, the idea has prevailed that it is utterly impossible to operate a mine without accidents. Although, as in all other kinds of industrial activity, it is true that some injury is likely on occasion to occur to some workers and an extraordinary accident may occur to one or more persons under exceptional conditions, mines can be operated with few if any accidents if a reasonable amount of the right kind of precautionary effort is exerted and kept in effect.

Jan 1, 1934

By R. S. Nutter

The results of designing, constructing, and laboratory testing of a modular, distributed, microprocessor-based mine monitoring and control system are presented. A standard computer communications protocol (DDCMP) was utilized throughout the system. Tests were performed on the utilization of a high-level language for programming mine monitoring and control systems. Laboratory tests were run on a combined air velocity/methane sensor.

Jan 1, 1980

By G. L. Anderson

The critical importance of wire rope integrity to the mining industry has led to the creation of standards for the retirement of wire rope as well as to the development of electromagnetic devices and procedures that would allow wire ropes to be tested against these standards without destroying them, The U.S. Bureau of Mines (USBM) conducted research to evaluate these devices by measuring loss of metallic cross-sectional area and the number of wire breaks, or local faults. The intent was to define the extent to which the technique can identify degradation within the rope, e.g., broken wires, corrosion, and wear. Experimental results showed that instrument sensitivity depended on a number of factors, including rope diameter, placement of sensors, location and characteristics of flaws, rope speed, and tension on the rope. The experiments also demonstrated the importance of having an elongated recorder trace and a properly trained and experienced operator to interpret overall results. A design of a rope and test procedures for use in laboratory evaluation of instruments have been recommended by the American Society for Testing and Materials Committee E07.07.10, Wire Rope Applications. The USBM is working through this committee to develop standards for an electro-magnetic method of wire rope inspection.

Jan 1, 2010

The following pages discuss the objectives, the background, the scope and a statement of the problem of the study of methods to improve the pillar extraction practices in underground coal mines. 1. OBJECTIVES The objectives of this project were: ? to determine the principal factors contributing to high accident frequency and severity in both conventional and continuous mining operations; ? to compare and evaluate the safety aspects of the "open end" and "split and fender" systems of pillar mining; to establish basic data required to decide what constitutes an adequate pillaring plan that will optimize efficiency, recovery, and safety; ? to determine what measurements or information should be collected, (e.g. roof sag, pillar stress,) to make on-the-spot judgment of impending roof or pillar collapse; ? to make recommendations to improve existing methods or to insure proper techniques are implemented, and ? to suggest areas where additional studies or new research may be of value.

Jan 1, 1975

By Walter W. Kaufman

This User's Manual, extracted from information contained in the Final Report for the above referenced project, outlines test procedures to measure the braking capabilities of underground non-coal rubber-tired mining equipment. Methods to interpret test results, recommendations for safe braking capabilities, and basic techniques to improve braking systems and road surfaces are also discussed. Possible applications for runaway vehicle protective devices other than braking systems are reviewed. Also included is a listing of mining equipment and brake component manufacturers who supply the majority of equipment to the United States non-coal mining industry. In conjunction with this list of manufacturers, a general tabulation of brake related specifications appears for vehicles observed during stopping tests conducted underground.

Jan 1, 1977