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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 Wilbert J. Huff

The work of the Explosives Division, Bureau of Mines, United States Department of the Interior, for the fiscal year ended June 30, 1939, is described in the following pages. This paper is the fourth of a series of annual reports covering the activities of the division since July 1, 1936. The studies outlined in this and preceding reports of the series have been conducted under the direction of the author and the respective unit leaders to whom specific credit is indicated.

Jan 1, 1940

By G. L. Oldright

"The various districts in the United States where complex lead-zinc ores occur are too well known to require description, there being hardly a mining State with any large amount of ores of either metal that is free from this problem. This paper briefly presents developments in the volatilization process, as applied to the treatment of such ores, since the data in Bureau of Mines Bulletin 211** were published. In that bulletin, among the many types of ore treated, examples are given of the treatment of lead-zinc ores by the chloride volatilization process for the separation of lead. An outline of the general process, with views of the rotary kiln, ore feeder, firing system (these three features resemble closely those of cement-kiln practice), dust chambers, and a Cottrell precipitator to remove the fume from the gas, are also shown in that bulletin, to which the reader is referred for the results obtained, and for practical details of operation. The small initial cost of a volatilization plant, and its adaptability for use in isolated districts were emphasized.In general, it was found that when an intensely oxidizing atmosphere was maintained in the furnace, a good lead-zinc separation could be made. Therefore, a heavy sulphide ore would have to be preroasted, and enough air would have to be admitted to obtain complete combustion of whatever fuel might be used.The work done by private companies and the bureau since the data for Bulletin 211 were obtained, indicates that the ores most immediately amenable to treatment by volatilization are of two types. The first is an oxidzed lead. silrer ore whose variable lime content makes it impractical to chloridize the ore for acidulated brine leaching, and whose base metal content makes treatment by cyanidattion unfeasible, The second type is the lead-zinc ore mentioned above, and is the one on which data are available for publication at present. This article Chows what ores of this latter type are amenable to treatment by volatilization, by giving briefly some of the more important physical and chemical properties an ore should preferably possess. Several examples are given from both laboratory experimental work, and from practice in the field, showing various phases of the volatilization process."

Nov 1, 1923

By Dennis R. Dolinar

Physical property tests were conducted on drill core from three exploratory holes on the Naval Oil Shale Reserve near Anvil Points, Colo. Data and regression analysis curves are presented. Data obtained above the Mahogany zone were used to estimate the potential zone of surface effects from under-ground mining. Single specimen testing was primarily used to obtain Mohr's envelope and subsequent rock properties. The technique is shown to provide satisfactory results for this rock type with a significant reduction of core preparation and testing time.

Jan 1, 1981

By J. R. Thoenen

"The curtailment of imports of foreign potash during the World War directed attention to the necessity of establishing a domestic source of potash for fertilizer, and considerable study has been given to the subject by Government bureaus, research organizations, and private individuals. These studies have covered all known sources of potash, and among them the extensive greensand deposits of New Jersey in which the potash content is found in the mineral glauconite have been investigated.Several hundred patents have been obtained covering processes for the extraction of potash from siliceous minerals, but up to the present time none have proved successful on a large commercial scale.When the investigation of the potash deposits of Texas was started by the Federal Government, the laboratory study of the drill cores was assigned to the Nonmetallic Minerals Experiment Station at New Brunswick, New Jersey, with the object of ascertaining a possible commercial method of utilization.The purpose of this preliminary study was to investigate existing literature and previous investigations to ascertain the extent and availability of the deposits, the extent of commercial success so far attained in potash extraction, the most promising known methods and by-products obtained from them, probable markets, and possibility of competition with foreign potash, and by a study of these data to determine whether further chemical engineering analysis and laboratory investigation were warranted.As the study advanced it became evident that adequate reserves of green-sand were available for many years supply. and that whereas many processes had been patented few had been tried commercially. In collaboration with former private and Government investigators these patents were first divided into two"

Feb 1, 1929

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 Wilbur A. Haley

One of the purposes of the investigation was to determine and report on how coal augers are used to mine bituminous coal that is near outcrops and may not be mined otherwise by any other present-day method. Such increased overall recovery results in the conservation of coal resources. Other reasons for the investigation were to determine and report the production rates of such operations and the types of equipment used. Auger mining of coal as a means of coal recovery supplementary to strip mining has been introduced and developed since World War II. This type of coal mining has grown rapidly, and bituminous-coal production by auger mining has been estimated at 6,000,000 tons in 1955. Mines were selected for study to give reasonably representative information on auger mining in different types and thicknesses of coal beds in different geographic areas and on different types and sizes of equipment operated under various conditions. This report is based on field studies of 8 auger-miming operations in Pennsylvania, West Virginia, and Ohio and in 5 different coal beds. Operations were observed in active strip mines, in strip mines reopened for auger mining, and along benched coal-bed outcrops. At the time of this study, no augers were reported to be operating in underground mines. The diameters of holes drilled ranged from 26 to 52 inches, and the lengths of holes ranged up to 208 feet. At some operations auger holes often penetrated abandoned underground mine workings.

Jan 1, 1957

By A. C. Munro

This paper, which describes the milling practice at the Britannia concentrator, Britannia Beach, B. C., is one of a series being prepared by the Bureau of Mines. The concentrator treats copper ore at the present rate of 6,000 to 7,000 tons of dry ore daily and produces copper concentrate and pyrite concentrate by selective flotation methods. The copper concentrate is smelted and the pyrite product is utilized for acid manufacture.

Jan 1, 1932

By Joan Weinberg

Real output expanded at a 3.0% rate worldwide in 1987, a slightly lower pace than the 3.2% rate in 1986. The decline was accounted for largely by slower growth in the U.S.S.R. and the East European countries, as well as in the developing countries (table 1). According to the International Monetary Fund, output of industrial countries output grew 3.1% and rose most strongly in Japan, the United Kingdom, and Canada (table 2). U.S. economic growth remained at 2.9%, the same as in 1986. Consumer and government spending declined in industrial countries, while gross fixed investment: rent increased. This increase in fixed investment expenditures could be attributed partly to lagged results of some 1986 developments: the fall in oil prices, declining interest rates, and exchange rate changes. The U.S. budget deficit, as well as the large external deficits and surpluses among major industrial countries, hindered further growth .2 A report from the Organization for Economic Cooperation and Development (OECD) indicates that the impact of the October stock market crash was short-lived because it hit economies that were growing strongly, anyway.3 The growth of output in the developing countries slowed in 1987; however, output declined in the fuel-exporting developing countries. These countries have been adversely affected by weakness in oil prices and the depreciation of the U.S. dollar. The weighted average of inflation rates in industrial countries--as measured by the [ ] GNP deflator, was 2.9% in 1987, down from 3.4% in 1986. Prices rose 3.0% in the United States, up from 2.6% the previous year. Inflation for 1988 is expected to remain slightly higher in the United States than in Japan and the Federal Republic of Germany because of recent exchange rates changes and the elimination of slack productive capacity and labor in the U.S. economy. Prices in developing countries as a whole rose more than 10 percentage points in 1987. Higher import prices, caused by

Jan 1, 1988

By Daniel G. DiCanio

This report describes a computer-based model for estimating the tangible costs of injuries and deaths from work-related accidents in underground coal mines. The study undertook to identify and quantify the elements of accident costs, including field visits to coal mines, insurance carriers, and public agencies. The mathematical models developed for each tangible element of accident cost are presented in Volume I of the report. A listing of the computer programs which comprise the model and instructions for using the programs are presented in Volume II. Statistical distributions of mining family characteristics, data on 95 miners killed in underground accidents, and other basic data used to develop the model are presented in Volume III. Application of the model to a data base of 9,286 accidents which occured in underground bituminous coal mines during 1974 yielded a total of $56,900,000 in tangible costs to industry, mining families, and public agencies. Loss of income to the families of miners injured or killed in these accidents accounted for 47 percent of the total.

Jan 1, 1976

By E. A. Magill

This report is one of a series prepared by the Bureau of Mines on manganese deposits of the Northwestern States. It describes properties on the Olympic Peninsula, Wash. Exploration by the Federal Bureau of Mines in 1939-40 and 1954-55 on several typical deposits is summarized, and examination data are presented for other manganese deposits on the peninsula. An attempt was made to list all known occurrences; however, some properties are abandoned, and their exact location is unknown.

Jan 1, 1960

By F. L. Wideman

This report describes a computer program that is used for the calculation of the coordinates and elevations of subsidence survey pins located by intersection. This program was developed for the Federal Bureau of Mines by the Numerical Analysis Laboratory, University of Arizona. These calculations, although relatively simple, are both tedious and time-consuming when computed with a desk calculator and trigonometric tables. In this survey, a large number of pins were surveyed repeatedly, and it was evident that both time and money could be saved by using a digital computer.

Jan 1, 1962

By Jack E. Fraley

In this Bureau of Mines study, sealants containing mineral wool, cement, etc, were sprayed through dry-process equipment that propels dry material pneumatically to the water-adding nozzle. Advantages over slurry applications include no mixing, no extensive cleanup, and freedom from hardened cement in equipment should power be lost. Sealants with large mineral wool nodules (>l-inch) were sprayable at rates to 900 square feet per hour for 1/2-inch thickness with little dust and smooth material flow through equipment, but they were weak for mine use, Materials containing small wool nodules (1/4-inch) were stronger but tended to plug lines because the nodules were inadequately separated in the shredder. Increasing the dedusting oil also increased line plugging by holding the nodules together in larger lumps. Best results were obtained using a 3/4-inch-nodule wool with cement binder, which provided both smooth flow through the machine and adequate strength.

Jan 1, 1977

[This Report represents the culmination of work perfomed under Contract No. .,JG1551A8 for the U.S. Bureau of Mine.The &apos;.:o-< embeded a site evaluation, engineering E:-y- ,, esign, and preparation of specifications for construction of a Transport Research 7 :4 (HTRF)The HTRF is designed as a research facility J evaluate the hydraulic transport of large lump coal at a prototype ;e scale. The HTRF is to be constructed and operated by the Pittsburgh and Safety Research Center of ;. re U.-AN a*, their Bruceton, Pennsylvania test center. In terms of technical capability, the HTRF will have transport pipeline:: of -, twelve-, and eighteen-inch diameter _&apos; with supporting coal handling n , water forage a.^ &apos;d conveyance, mixing, pumping, and dewatering equipment, plus instrumentation and controls. Maximum design velocity 13 20 ft/sec.; solids concentration, by, volume, will; 1 be a maximum-- of sixty, percent. Each test loop is designed to accommodate solids of up to one-third the diameter e - of the pine. The Final Report Pr.-&apos;I-rents information of t HTHF,. including the site evaluation, design criteria, a description of the a description of the procedure to be used for operation of the facility, an estimate of the cost to construct the f^Cilit:r, 1 p el_~lli.&apos;iU construe`, icn Schedule, and a construction suicJ_iicaT.l_ccn&apos;. T e c011SLr?Jc&apos;.ion soecl_ i.on _ccnta_i:s technic.&apos;..i re7,uir: (-n`,s for !&apos;urr1S~ &apos;~latcr..al. and ec-uipr,ent for :":C1 C_`:_C ti on of ti,_ H ice&apos; u:&apos;.:i ._II u s(-.6 for ~.Iir: .3!7 soliciting bids. `.l_o included n cc&apos;;,art_- c?r~.air sV:et..: :s ^nd rr^.?]

Jan 1, 1976

By R. N. Johnson

This report is a summary of the work performed for the Bureau of Mines to evaluate the feasibility and desirability of a movable in-pit crusher combined with conveyors to substantially reduce or eliminate truck or train haulage in large open-pit non-fuel mineral mines. The report includes an introduction and summary of previous work, an analysis of movable crusher system components, a description of the selected system, a review of possible movable crusher system applications, and finally requirements for future work to bring about the general availability of such systems. It was clear from the program that there is a real need for movable in-pit crushers.

Jan 1, 1982

By M. Kanda, W. D. Bensema, J. W. Adams

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in and above an operating coal mine, McElroy Mine, located near Moundsville, Nest Virginia. The electromagnetic environment created by 300 volt dc and 480 volt ac machinery was measured. In one technique noise was measured over the entire electromagnetic spectrum of interest for brief time periods. The noise was recorded using broadband analog magnetic tape. The noise data was later transformed to give spectral plots. In the other technique, noise amplitudes were recorded at several discrete frequencies for a sufficient length of time to provide amplitude probability distributions. The specific, measured results are given in a number of spectral plots and amplitude probability distribution plots.

Jan 6, 1974

By K. C. McMahon

This report is the result of the engineering efforts performed by the Mining Equipment Operations of FMC to develop methods of automating a continuous miner. This work was done as part of modification number three of the contract for the development of a miner/bolter system. As the demand for energy places an ever-increasing pressure on the coal mining industry to produce more coal, methods for underground mining which will increase productivity with a con-current increase in safety are being actively sought. Removing the machine operator from his station on the continuous miner and placing him at a safer location behind the machine while retaining his control functions via an umbilical cable or a radio link was an important first step. However, the problems of poor visibility, no control "feel", and the judgmental problems of controlling the sump distance and the shear limits have not been conducive to the productivity increase that is desired.

Jan 1, 1975

By F. N. Bender

Percolation leaching of wad-type manganese ores was investigated, using a novel system of alternate upward passage of sulfur dioxide gas through moistened ore and downward percolation of wash solutions to extract solubilized manganese. Bench and large-scale tests designed to simulate vat and heap leaching were made on four wad ores from Arizona and Nevada and on a pailomelane ore from Arizona. Three of the wad ores required prebaking at 500° to 600° C. to produce a permeable agglomerate that would not slake during percolation washing. The hard-type ore and one of the wad ores that contained a large amount of granular gangue did not require prior roasting. The deportment of the different ores toward leaching and percolation was studied with particular reference to the influence of the sulfur dioxide - oxygen ratio and the effect of gas dilution on the rate of manganese dissolution, dithionate formation, and acid production. Crushed charges of the ores, as coarse as 1 inch and as fine as 1/4 inch, were treated for periods of 5 to 11 days. Percolation of the gas and leach solutions through the charges was achieved without difficulty. The manganese extractions varied between 78 and 97 percent and depended upon the size and type of ore leached. The average quantity of sulfur dioxide required in the larger scale tests was about 2.6 pounds per pound of manganese recovered. The dithionate formation varied from 0.35 to 0.9 pound per pound of manganese extracted depending upon the strength of leaching gas.

Jan 1, 1957

By Charles B. Kenaban

The possibility of using ultrasonic energy as a tool to improve the electrolytic deposition of copper and zinc from several electrolytes was investigated by the Federal Bureau of Mines. Sound with frequencies of 20, 26, 38, and 400 kilocycles per second and acoustical intensities of 0.25 to 1.5 watts per square centimeter was employed. Measurements of cell voltage, anode and cathode current efficiencies, and electrode potentials were made at various current densities. Effects of ultrasonics on the quality of the deposit and on anode corrosion also was noted. In the electrolytic recovery of copper from an acid copper sulfate solution at 50° C., adherent, well-consolidated deposits are normally obtained up to a current density of 30 amperes per square foot. As the current density is increased above this value, the deposits normally become progressively more spongy and less adherent. Ultrasonic irradiation resulted in adherent and well-consolidated deposits at current densities up to 300 amperes per square foot. Radiation also produced smaller grain size and preferred orientation of the copper crystals. In addition, radiation caused as much as 3-volt decreases in cell voltages at the higher current densities. These decreases were caused chiefly by depolarization of the anode, although small depolarization effects were also noted at the cathode. Radiation apparently did not greatly affect cathode-current efficiencies, but prevented excessive anode corrosion at the higher current densities and resulted in more uniform corrosion. Ultrasonic radiation at a frequency of 400 kilocycles per second was not as effective as radiation at the lower frequencies. Circulation of the electrolyte at rates up to 5 percent of the cell capacity per minute did not produce results comparable to those effected by ultrasonic radiation. Rapid rotation of the cathode up to 1,800 revolutions per minute gave results approaching those obtained with ultrasonics.

Jan 1, 1961

By Dean H. Ambrose

[Mining and processing earth&apos;s materials form the basic building blocks from which many technology advancements and products are made. Virtually all metallic and non- metallic products are derived from a substance found in our earth that we blend, mold, extrude, or pulverize into something useful, the mining industry is responsible for the first step of this process: extraction from the ground. Mining particularly coal mining. poses significant risks to both humans and machines. As raw materials are]

Jan 1, 2009