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By S. R. Zimmerley

[In the course of a flotation investi~ntion, a siliceous gold ore was ground ir, R 'ball mill to ~inils 300-mesh. It mas found that the small mount of zlus 300-~esh mnterial had a go12 assw approximately twice that of the oricinal ors, md thst this oversize ~roduct also contained much abra?.ed iron. >!oreover, the gold assay of the abraded iron, which was separated ma~etic-dl:;, wno ei::ht tiaes tkat of the ore. These facts sug,~estsd th~t sone r3laticnshin existed between the abnormally high .gold content and the preseace of abrade4 iron. It was ciecided, therefore, to investl~ate furtkor ths acsoclation of the ;old nith the iron abraded from the balls durir-g grincing. As a nrelininary ex?rr>hent, a samy?le of siliceous gold ore 786 grolznd for 1-1/2 hours i;l 3 ball mill and the nuln was divided into two products electri~mag-etically. The racult s follow: ]

Jan 1, 1937

By Victor V. Verbinski

This report presents the development of a raw coal concentration sensor for hydro-transport of coal and refuse (rock) from underground mines, and the results of an international test series carried out at the Colorado School of Mines Research Institute in Golden, Colorado, the U.S. Bureau of Mines, Hydraulic Transport Research Facility in Pittsburgh, Pennsylvania, Saskatchewan Research Facility in Saskatoon, Saskatchewan, Canada, and the Steinkohlenbergbauverein Test Facility in Essen, West Germany. Test results are presented for a three-component sensor and also for the more rugged two-component (all nuclear) sensor.

Jan 1, 1988

By Bernard Lewis

This report on the research and technical studies conducted by the Explosives Branch of the Bureau of Mines covers the 2-year period July 1, 1946, to June 30, 1948. A report for the fiscal year 1947 was omitted because of the large amount of work still in an unfinished state. The material presented herein is based largely upon more comprehensive reports prepared under the authorship of members of the branch staff.

Jan 1, 1949

By R. R. Allen

[The utilization of Western coals and lignite is a continuing study of the Bureau of Mines, and storage of these fuels is of paramount importance. Since the seasonal demand for coal in the Western States triples between the summer and winter months, successful storage of these low-rank fuels would tend to level out this variation and should reduce fuel costs. The time is rapidly approaching when the West Coast States, particularly California, will annually import several million tons of coal from the Rocky Mountain States for additional power production. This will necessitate storage of large quantities of coal, and it is thefore important to develop experience in such storage. Dry surface storage, by virtue of its flexibility and low cost, is particularly adapted to the stockpiling of large quantities of coal. This report will, therefore be primarily concerned with such storage. Inasmuch as the problems of dry, open-pit storage are quite similar to those of surface stockpiling, experiences in pit storage will be discussed briefly. Although spontaneous combustion is a hazard in storing coal, experience has proved that heats can be avoided by proper stockpiling procedures. The purpose of this report is to show that the most reactive coals can be stored satisfactorily on the surface by avoiding segregation and by thorough compaction.]

Jan 1, 1954

By Clarence Hall, Spencer P. Howell

Among the more important factors involved in the use of high explosives in blasting operations is the means employed to bring about the detonation of the charge. When flame is applied to high explosives many of them may burn if not confined; but all of them when burning under certain conditions of confinement may detonate. Detonation may also be effected by mechanical means, such as frictional impact caused by a blow or by rubbing between surfaces. By this means, however, the full effect of the explosive charge may not be developed, so that a partial detonation, often accompanied by the burning of the explosive, results. When nitroglycerin was first used it was fired by the application of flame, but considerable difficulty was experienced in exploding it with certainty and in obtaining uniform resl'llts. In 1864 Allred Noble, a Swedish engineer, discovered that nitroglycerin could be surely and completely detonated by exploding in contact with it a small quantity of an initiatory explosive. Mercury fulminate was the substance then found capable of producing the best results There are many other fulminates and other substances that will produce complete detonation of commercial" high" explosives, but detonators or electric detonators containing mercury fulminate as the characteristic ingredient are still almost exclusively used in this country. The term" detonator" is used in the publications of the Bureau of Mines to designate what the miner calls a "blasting cap "-a copper capsule containing a small quantity of some detonating compound that is ignited by a fuse. The term" electric detonator" is applied to a blasting cap that is similar except for being ignited by means of a small wire which is heated to incandescence or fused by the passage of an electric current. One of the conditions prescribed by the Bureau of Mines for a permissible explosive a is that it shall be :fired by a detonator, or preferably an electric detonator, having a charge equivalent to that of the standard detonator used at the Pittsburgh testing station. A further requirement is that this charge shall consist by weight of 90 parts of mercury fulminate and 10 parts of potassium chlorate (or their equivalents). At the request of a manufacturer of permissible explosives, an investigation was undertaken by the bureau to determine the relative strength of detonators and electric detonators having different compositions. The tests of electric detonators herein reported were conducted by H. F. Braddock, junior chemist; J. W. Koster, J. E. Tiffany, junior mining engineers; and A. S. Crossfield, junior explosives chemist, at the Pittsburgh testing station of the bureau. Similar tests of detonators were not conducted because it was believed that the results would not show sufficient variation to warrant such tests. It is hoped that the conclusions drawn from the tests made will be of service to those using explosives by enabling them to select the grade of detonator or electric detonator that will insure the most effective results. The conclusions are given in this bulletin, which is published by the Bureau of Mines as one of a series of publications dealing with the testing of explosives and the precautions that should be taken to increase safety and efficiency in the use of explosives in mining operations. The results of tho experiments described in this bulletin show that the average percentage of failures of explosives to detonate was increased more than 20 per cent when the lower grades of electric detonators were used instead of No. 6 electric detonators, and was increased more than 50 per cent when these lower grades were used instead of No. 8 electric detonators. It is noteworthy, however, that when sensitive explosives, such as 40 per cent strength ammonia dynamite (p. 33), were tested under conditions ideal for detonation, the same energy was developed irrespective of the electric detonator used. When tests were made with a less sensitive explosive, such as a 40 per cent strength ammonia dynamite containing nitrosubstitution compounds (p. 32), the energy developed increased with the grade of the electric detonator used. For example, the average efficiency of four different explosives was increased 10.4 per cent when a No.6 electric detonator was used instead of a No.4 electric detonator, and 14.9 per cent when aN 0.8 electric detonator was used (see tabulation onp.45). The results of the tests emphasize the importance of using explosives in a fresh condition, but as fresh explosives can not always be had in mining work, strong detonators should be used in order to offset any deterioration of explosives from age.

Jan 1, 1913

By Griffith. F. E., Glei

"INTRODUCTION For many years protective grounding of electrical equipment has been advocated as a means of safeguarding equipment against damage and of minimizing shock hazards to persons. Several codes are in effect covering in considerable detail the items to be observed in obtaining effective grounding in and about industrial plants. Although the coal-mining industry does not have a comprehensive code of its own covering the grounding of electrical installations, a number of States and individual coal-mining companies have issued codes, standards, or rules that include certain requirements with reference to grounding. As early as 1916, 4/ and again more recently, 5/ the Bureau of Mines recommended grounding, particularly as a means of preventing shock to men working on or around electrical equipment.It is common knowledge among electrical engineers of public utility and mining companies that connecting a wire from the frame of a machine to a rod or pipe driven into the earth does not necessarily assure desired protection of surface equipment. In fact, it has often been found necessary to use several interconnected rods and to treat the surrounding earth with salt or other chemicals before the connection to earth would have sufficiently low resistance to give satisfactory results. Even these expedients have not produced the desired results in some localities. It has also been found that ground connections initially having a low resistance may attain high resistance during some seasons of the year. In spite of such difficulties with surface equipment, it has sometimes been assumed that a mining machine resting on the floor in a coal mine is grounded by virtue of its contact with that floor. It has also been assumed by persons endeavoring to comply with grounding requirements that a peg or rod driven into the mine floor would provide a sufficiently low-resistance contact with the earth to be satisfactory as an electrode for connecting the grounding wire from frames of equipment. That both assumptions may be wholly untrustworthy has been proved by the authors in actual tests with underground machinery."

Dec 1, 1943

By R. S. Dewey

The purpose of this study was to assess the various aspects of public safety related to the thousands of abandoned or inactive underground mines found throughout Western Colorado. Review of available published mine inventories yielded data on over 8,000 abandoned underground mines. A random sample of 200 mines was then selected for field visits representative of mining activity in Colorado. Inspections of the openings at two hundred abandoned underground mines were performed recording descriptive information regarding the opening, the mine site, the surrounding area, the primary opening hazard, secondary hazards related to structures or dumps, other openings to the same mi ne, available construction materials, possible safeguard methods, and any special observations such as apparent activity, previous closure attempts, environmental constraints on construction, and access problems. Of the 200 mines visited, twenty mine openings representative of varying geologic, environ-mental, access, and mining conditions were selected for detailed low-cost safeguard application. Description of these safeguards is presented in narrative, itemized labor-materials equipment tabulations, and illustrations. Research into the regulations of mine closure and safeguards was also undertaken to determine jurisdiction of public lands. Recommendations were suggested to improve the awareness and ability to continue this program into an implementation stage.

Jan 1, 1980

By Will B. Jamison

An ignition detection and suppression system was developed under the scope of this contract. The objective of this machine mounted system was to detect flames caused by frictional sparking from the cutting bits of a continuous mining machine and to suppress it with sufficient speed to prevent the development of an explosion, and to keep the flame from harming the machine operator.

Jan 1, 1976

By William C. Morel, Sidney Katell

This report covers the period January 1964 through December 1964; it is a continuation of the series that began with the publica- tion of Information Circular 7516 in October 1949. Also, it is the sixth in a series of reports prepared under a cooperative agreement between the Bureau of Mines and the American Association of Cost Engin- eers. The agreement provides for the publication of an annual cost bibliography with the work load involved in the preparation shared equally. The abstracted articles, concerned with all facets of cost engineering in the field of chemical and petroleum plants and related subjects, are from the following sources: 1. American Association of Cost Engineers Bulletin. 2. Bureau of Mines Information Circulars. 3. Bureau of Mines Reports of Investigations. 4. Chemical Engineering. 5. Chemical Engineering Progress. 6. Chemical Week. 7. Coal Age. 8. Coal--Today and Tomorrow. 9. Cost Engineering. 10. Hydrocarbon Processing and Petroleum Refiner. 11. Industrial and Engineering Chemistry. 12. Nucleonics. 13. 011 and Gas Journal. 14. Petroleum Management. 15. World Oil.

Jan 1, 1965

By Robert J. Anderso

Few elements have received more attention and developed greater interest in the last ten years than titanium. The substantially pure metal has been din...ie. cult to isolate, and so far has been little employed oommercially, but the use af alloys and chemical compounds of titanium has increased markedly in recent years. The earlier attempts at preparing pure titanium resulted in various impure forme which, from their metallic appearance, were always mistaken for the metal. Hunter in 1910 isolated pure titanium by the reduction of titanium tetrachloride with sodium. This brief statement is issued by the Bureau of Mines in response to numerous inquiries which have been received concerning titanium. More complete in. formation on the metal may be had by consulting the referenpes appended. The Literature is voluminous and only the more important references are Riven. It has been drawn upon freely in preparing this report; also information was supplied by M. g. Hunter, Arthur Braid, M 1. Schmid, C. M. Johnson, N. B. Hoffman, and de Courny Browne. The pioneer investigator in titanium is A. IL Rossi.

Oct 1, 1922

By Sidney Katell

This report covers the period January 1964 through December 1964; it is a continuation of the series that began with the publication of Information Circular 7516 in October 1949. Also, it is the sixth in a series of reports prepared under a cooperative agreement between the Bureau of Mines and the American Association of Cost Engineers. The agreement provides for the publication of an annual cost bibliography with the work load involved in the preparation shared equally. The abstracted articles, concerned with all facers of cost engineering in the field of chemical and petroleum. plants and related subjects, are from the following sources:

Jan 1, 1965

By Sidney Katell

This report covers the period January 1964 through December 1964; it is a continuation of the series that began with the publication of Information Circular 7516 in October 1949. Also, it is the sixth in a series of reports prepared under a cooperative agreement between the Bureau of Mines and the American Association of Cost Engineers. The agreement provides for the publication of an annual cost bibliography with the work load involved in the preparation shared equally. The abstracted articles, concerned with all facers of cost engineering in the field of chemical and petroleum. plants and related subjects, are from the following sources: 1. American Association of Cost Engineers Bulletin. 2. Bureau of Mines Information Circulars. 3. Bureau of Mines Reports of Investigations. 4. Chemical Engineering. 5. Chemical Engineering Progress,

Jan 1, 1965

By Henry Kreisinger, John Blizard, B. J. CROSS, C. E. Augustine

This report gives the results of 26 tests of a four-pass Edgemoor boiler fired with powdered coal at the Lakeside station of the Milwaukee Electric Railway & Light Co. The tests were made by the fuel section of the Bureau of Mines in cooperation with the research department of the Combustion Engineering Corporation and the operating department of the Milwaukee Electric Railway & Light Co. The object of the tests was to determine the thermal efficiencies and capacities obtainable by burning powdered coal under large central-station boilers, and the possibility of operating such boilers continuously at high efficiency and capacity without destructive effect on the furnaces and without difficulties in refuse removal. In any system for burning pulverized coal the furnace is the most important part because, to justify the cost of pulverizing, the powdered coal must be burned with higher efficiency than coal fired with mechanical stokers. In other words, it is the furnace that by giving higher thermal efficiency must pay for the installation, maintenance, and operation of the pulverizing equipment. No matter how simple the apparatus for the preparation of pulverized coal may be, or how simple the pulverizing process, unless the furnace is so designed that it can be operated continuously with high thermal efficiency, the whole system is a failure. For high thermal efficiency the coal must be burned almost completely with low excess air. But low excess air and complete combustion give high furnace temperature, which in turn causes erosion of the furnace lining and fusion of the ash; and removal of the fused ash is difficult. The necessity of complete combustion with low excess air thus brings with it these two important problems in the design of a furnace for burning powdered coal: 1, Prevention of erosion of the furnace lining; 2, easy removal of refuse from the furnace. For the purpose of solving these problems, the boiler tested was equipped with a furnace having hollow walls, through which about 60 per cent of the air needed for combustion passed before it entered the furnace. By passing through the hollow walls, the air cooled the furnace lining and prevented excessive erosion. A water screen was placed in the furnace about 3 feet above the bottom to keep the refuse deposited at the bottom from fusing and to make its removal easy. The design of the furnace, water screen, and burners was based on the experience gained in the previous cooperative tests1 with a smaller furnace, experimental water screen, and burners at the Oneida Street station of the Milwaukee Electric Railway & Light Co. The boiler tested had 13,057 square feet of heating surface. It was one of eight boilers fired with powdered coal, and was designated as boiler No. 8. The Lakeside station is the largest central station in the world that burns powdered coal exclusively. The coal used in the first five tests came from Illinois. The fuel in the other tests -:vas a mixture of Illinois and Pittsburgh coals.

Jan 1, 1925

By Lloyd L. Farnham

This paper is one of a series describing the mineral resources of the Nation, including location, history, production, ownership, geologic setting, and mining methods for most of the known manganese deposits in New Mexico, With few exceptions these descriptions are the result of field examinations by the writer. Of 32 counties, the 12 which occupy the western half of the State contain all the known manganese deposits, These counties are Catron, Dona Ana, Grant, Hidalgo, Luna, Rio Arriba, Sandoval, Santa Fe, Sierra, Socorro, San Juan, and Taos. (See fig. 1.)

Jan 1, 1961

By S. H. Ash

THE ANTHRACITE region of Pennsylvania contains over nine-tenths of the total anthracite deposits of North America and produces all but an insignificant proportion of the total output of anthracite in the Nation. The whole economy of the northeastern section of the United States depends, to a large extent, on the mining of Pennsylvania anthracite, which is shipped to New Jersey, New York, and New England and is a principal source of energy and heat for that entire region. The responsibility of the Federal Government for developing an engineering method that will prevent inundation of the Pennsylvania anthracite mines and keep them in operation has long been recognized. To obtain a reliable picture of the anthracite-mine-water problem and to solve that problem, it is necessary to have factual data on the volume and the quality and character of the mine water handled by the pumping plants in the anthracite region, as well as the kinds of pumps utilized and problems concerning their operation.

Jan 1, 1953

By Ross. C. Barkley

A computer program has been written to simulate ground vibrations induced by multiple-hole surface blasts. The program is an inexpensive and relatively easy to use tool for predicting the principal blast vibration characteristics that determine damage and annoyance potential: peak particle velocity, frequency content and pulse duration. The program generates a complete ground motion history by superposing, at any surface position, the vibrations induced by each individual explosives charge. It requires specification of (hence allows accounting for) the blast geometry, initiation sequence (including random delays), position with respect to blast, pulse characteristics induced by each charge, and propagation laws. A methodology is outlined to determine the necessary variables either on the basis of site investigations (e.g. velocity, attenuation, pulse), or by backcalculation from measured blast vibration records. The latter procedure has been applied to blasts from two coal strip mines. Main difficulties are backcalculating individual pulses, propagation (especially dispersion) parameters and delays. A normal distribution of delays, based on published results, has been shown to influence the results and the response of a single degree of freedom structure significantly. Broadening of the wave types included and additional verifications with field results are required.

Jan 1, 1983

This Bureau of Hines report on underground mine communications addresses methods and equipment to meet the communication requirements of working sections and places of coal and metal-nonmetal mines. A review of the status of trapped miner detection is also presented.

Jan 1, 1977

By Robert T. MacMillan

A process has been developed in the laboratory and expanded to semi-pilot-plant scale for recovering titania, iron, and byproducts from two types of titaniferous iron ores. A reducing roast with coke and soda ash followed by grinding and magnetic separation produced powdered iron and slag from which titania and byproducts were recovered by H2SO4 decomposition. Based on the steps tested on a. semi-pilot-plant scale supplemented by the results of the laboratory investigations, enough data are available to make a balanced flow sheet. Combined data from the laboratory and semi-pilot plant indicated that 85 to 9O percent of the titania content of the ore was recoverable and that approximately 90 percent of the iron could be recovered as a metallic-iron powder. Tahawus magnetite from the Maclntyre mine at Tahawus, N. Y., was successfully treated as follows: (1) The ore was roasted at 1,050° to 1,080° C. with carbon and soda ash, thereby reducing the iron to metal sponge and retaining the titania in the slag. (2) The metallic iron was separated, after wet grinding, by magnetic or gravity means. (3) The slag fraction was air-roasted at 850° C. and leached with NaOH to recover Na3VO4. (4) The leached solids received a dilute-H2SO4 leach to remove interfering impurities, chiefly Na2O and SiO2. (5) Titania was dissolved from the leached solids of step (4) by a H2SO4-bake followed by a water leach. (6) Titania was precipitated by seeding and boiling the resulting solution. The spent liquor was used for the dilute-H2SO4 leach in step (4). The following scheme was found to be technically feasible for recovering other byproducts of the process. (1) The gelled filtrate from the dilute-acid leach step was washed and dehydrated to produce a commercially acceptable silica gel. (2) The wash liquor containing sulfates of Na2O, Al2O3, Fe2O3, and TiO2 was combined with the highly alkaline filtrate from the wet-grind and metallic iron-separation steps, precipitating iron and titanium hydroxides, which were separated for special treatment. (3) Anhydrous Na2SO4 and Al2O3?3H2O were recoverable from the alkaline filtrate from step (2) by evaporation and carbonation, respectively, and the barren liquor was recycled to the magnetic-separation step.

Jan 1, 1952

By S. S. Venkata

This volume describes a comprehensive program of research into the reliability of mine electrical power system components and the resultant reliability of the total system. The research effort encompassed analytical models, laboratory testing and field testing. The analytical work included definition of terms, fail rate functions and distributions, failure rate estimation and techniques and procedures for theoretical reliability assessment. One of the primary mine power system components addressed in the study was the ac molded case circuit breaker. This device is known to have low reliability and hence an unfavorable impact on mine safety and productivity. Ac molded case circuit breaker reliability was studied by analytical means, laboratory testing and field monitoring. A similar three-pronged' effort was made to study the reliability of undervoltage relays/releases. Particular emphasis was placed on new solid state undervoltage relays. The reliability of bulk power components, such as trailing cab les, motors, control gear, and other equipment, was assessed by gathering maintenance records from active mines. These data were compared to similar records from other industries. The work was extended to include the reliability, availability, maintainability and safety of these components.

Jan 1, 1979

By Ronald B. Stotelmeyer

This report summarizes the U.S. Bureau of Mines evaluation of the mineral resources of eight roadless areas in several National Forests in Montana. The areas are amoung those that have been proposed as additions to the National Wilderness Presevation System In various sessions of the U.S. Congress. Mineral Commodities present include gold (lode and placer), silver, copper, lead, zinc, molybdenum, tungsten, rare-earth elements, fluorite, and barite. Numerous mineral deposit types occur. Past production was from gold placers and vein-type deposits. There is potential for development of large volume porphyry copper-molybdenum, disseminated gold, stratabound copper-silver, and exhalative massive-sulfide metallic deposits. A substantial increase in metal prices is needed before any known vein-type deposits will be economic.

Jan 1, 1994