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By P. L. Woolf

An investigation was conducted to evaluate the use of a formcoke as the total fuel in the Bureau of Mines experimental blast furnace. The formcoke performed very satisfactorily, and comparisons made with a metallurgical coke showed that the performance with the formcoke was somewhat superior under the experimental conditions used.

Jan 1, 1966

By Alla D. Mah

Titanium forms several compounds with oxygen and also is able to dissolve interstitially about 33 atomic percent of oxygen. Starting with titanium dioxide, reduction becomes increasingly difficult as oxygen is removed; and the final step, be reduction of the titanium-oxygen interstitial solutions, is by far the most difficult. The possibility of reducing titanium oxide, or of purifying titanium containing oxygen, by treatment with certain more volatile metals has been a subject of considerable interest. Theoretical appraisal of the limitations of this possibility, however, has been hampered by lack of adequate information on the thermodynamic properties of the titanium-oxygen solutions. The purpose of the present work was to remedy this difficulty by expanding the thermodynamic knowledge regarding these solutions. The experimental work involved three types of calorimetry and furnished the following information: (1) Heats of formation of 11 titanium-oxygen solutions, in the range of 0 to 10 wt.-percent oxygen, were determined at 298.15° K. As a byproduct, an improved value of the heat of formation of rutile was obtained, which, in turn, led to improved values of the heats of formation of the lower titanium-oxygen compounds. (2) Low-temperature heat-capacity data and entropies at 298.15°K in were determined for 2 representative titanium-oxygen interstitial solutions. (3) High-temperature heat-content data were obtained for 2 titanium-oxygen interstitial solutions to about 1,600° K.

Jan 1, 1957

By John C. Hartley

Large areas of the anthracite beds in the Wilkes-Barre, Pa., region have been first-mined in such a manner that over half of the original coal has been left underground as pillars to support the overburden. To recover the maximum amount of this remaining coal, improved devices to support the roof while pillars are being extracted are needed. Also needed are suitable backfilling systems that will stabilize the strata during the mining and effectively limit the inevitable subsidence after pillars are removed. Accordingly, the Federal Bureau of Mines furnished 400 yielding steel props that had been purchased abroad, where this type of prop had been used successfully. The cooperating company arranged for concurrent tests with a mechanical stower designed and built by an American manufacturer. In the area in which the experiments were conducted, pillar removal, using conventional timbering, was most difficult because the roof fractured badly, the installation of timbers consumed a substantial part of the work effort, and some coal nearly always was lost. With the application of the yielding props, the time needed for securing the roof was reduced 33.9 percent; production per man-shift was in¬creased over 33 percent; coal recovery was improved more than 9 percent; and the convergence between roof and floor, during mining and backfilling, amounted to as much as 8.03 inches without any break in the roof. However, in September 1953 some roof rock fell in pillar 10 owing to insufficient props in a small area where the ends of three top holes drilled in the coal face extended up into the roof rock.

Jan 1, 1956

By Paul B. Harder

Round Mountain Gold (RMG) in central Nevada, reports that over a nine-year period and a million operating hours, its fleet of 150-ton and 190-ton haul trucks has averaged better than 93% availability, with some of the trucks approaching 70,000 operating hours. Repair costs have been far below industry averages. Mine operations manager Pete Kesl credits the high availability and low repair costs to a succession of Product Support Agreements between RMG and Caterpillar dealer Cashman Equipment. He adds that good equipment and a high level of trust and co­operation between all parties to these agreements have been essential to their success at Round Mountain.

Jan 1, 1998

By F. X. Tartaron

Behavior of hard-burned quicklime was compared with that of soft-burned quicklime in an oxygen converter utilizing oxygen blowing in a rotating cylindrical vessel, set at a 30° to 60° angle to the horizontal and operated at a predetermined speed of rotation. Four pairs of tests were made) each comparing hard lime with soft lime. Three of the pairs differed from one another in the quantity of lime employed) and the fourth differed in blowing time, All four pairs showed an increase in yield when soft lime was used. Three of the pairs revealed that the ratio of the oxygen consumed with soft lime to the oxygen consumed with hard lime was the same as the ratio of metal yield with soft lime to the metal yield with hard lime. The fourth pair contained an error and could not be included. Finally, a close inverse relation was found between the combined iron in the slag and the combined lime in the slag, which can be expressed by the equation pct Fe = 52.67 -0,906 (pct CaO).

Jan 1, 1967

By Paul B. Harder

Round Mountain Gold (RMG) in cen­tral Nevada, reports that over a nine-year period and a million operating hours, its fleet of 150-ton and 190-ton haul trucks has averaged better than 93% availability, with some of the trucks approaching 70,000 operating hours. Repair costs have been far below industry averages. Mine operations manager Pete Kesl credits the high availability and low repair costs to a succession of Product Support Agreements between RMG and Caterpillar dealer Cashman Equipment. He adds that good equipment and a high level of trust and co­operation between all parties to these agreements have been essential to their success at Round Mountain.

Jan 1, 1998

By John C. Edwards

A fire location computational model was developed by the U.S. Bureau of Mines. The model can determine all the possible paths in a mine that smoke can travel from a fixed fire source to a smoke detector. The associated FORTRAN computer program can be utilized to determine the minimum travel time from a source fire to a smoke detector. The difference in travel time from an isolated fire source to two or more detectors can be used to isolate those airways in which the source fire is located.

Jan 1, 1990

By W. T. Westbrook

This Bureau of Mines report contains methods for analyzing iron are for total iron, ferrous iron, metallic iron, silica, manganese, aluminum, calcium, magnesium, phosphorus, titanium, carbon, sulfur, moisture loss, and ignition loss by wet chemical methods. Some are modifications of standard umpire methods; others have been developed by the Bureau of Mines to provide a com-bination of speed and accuracy. They are suitable for a high volume of samples and/or control situations, and for situations in which instrumental results must be verified. These methods have been used to analyze taconites, native ores, some foreign ores, and metallurgical products.

Jan 1, 1975

By G. J. Slavens

The U.S. Bureau of Mines conducted research on preparing submicrometer titanium nitride (TiN) powder as a substitute for tungsten carbide (WC) in cutting tools and wear-resistant parts. Earlier research on a small scale was expanded to include a larger reactor. The TiN powder was produced by contacting titanium tetrachloride (TiCI4) with anhydrous ammonia (NH3) in the presence of Mg at 1,100° C. The powder was collected in an electrostatic precipitator (ESP) filled with ultra-high-purity (UHP) Ar. All collected powder was thermal vacuum distilled to remove Mg and magnesium chloride (MgCl2), leaving the purified TiN. Powder handling and purification procedures were conducted to assure low oxygen content in the powder product. Oxygen content in the distilled TiN powder product was as low as 0.40 wt pct. Nitrogen averaged near 22.0 wt pet with a high of 22.4 wt pct. The purified powder product had an average median particle diameter of 0.14 µm with a standard deviation of 0.09 µm.

Jan 1, 2010

By Forrest T. Moyer

THIS CHAPTER of the Minerals Yearbook (Volume III) contains overall injury experience for coal mines, both anthracite and bituminous coal, coke plants, petroleum and natural gas, peat, and asphalt and related bitumens (native); metal mines, metallurgical plants, including ore-dressing plants and primary nonferrous reduction plants and refineries; nonmetal mines; nonmetal mills; sand and gravel operations; slag (iron blast-furnace) plants; and stone quarries and their related plants. Volume I of the yearbook contains a chapter showing injury experience and employment data treated separately by categories: Metal mines, nonmetal mines, quarries and their related plants, metallurgical plants (ore-dressing plants and primary nonferrous reduction plants and refineries are shown separately), nonmetal mills, sand and gravel plants, and iron blast-furnace slag plants. Volume II contains injury and employment experience in the fuel industries (anthracite, bituminous coal including lignite, coke, petroleum and natural gas, native asphalt and related bitumens, and peat). Injury and employment data were collected from coal producers on the regular mandatory basis as required by the Federal Coal Mine Safety Act (30 U.S.C., sec. 455). Similar data for 1962 from metal, nonmetal (except well and brine operations), stone, and sand and gravel producers were collected by a. mandatory reporting system under the provisions of the Act of September 26, 1961, Public Law 87-300 (75 Stat. 649). Before 1962, these nonfuel producers reported voluntarily to the Bureau of Mines. Producers of all other minerals (fuel and nonfuel) reported the requested injury and employment data voluntarily to the Bureau for 1962, the same as in preceding years.

Jan 1, 1963

By Lewis C. Karrick

Although the Bureau of Mines has thus far made no large-scale experiments with oil shales, and the feasibility of the commercial manufacture of shale-oil products suited to present market requirements has not been demonstrated, there is ample reason to believe that these products will eventually supplement the more commonly used petroleum products and give equally good service. In 1919 the bureau, in cooperation with the Department of Metallurgical Research, University of Utah, began investigating the oil shales of the United States to obtain detailed information on their value. The States of Colorado and Indiana also cooperated through their State universities, in which research laboratories were organized to assist in carrying on the oil-shale studies planned and directed by the bureau. As a result of these studies much information is now available concerning laboratory methods of producing the greatest yields of the best products from oil shale. In order to study the principles that govern the retorting of oil shales and to test the oils produced, it has been necessary to develop and standardize reliable apparatus and methods for distilling shale, and to adapt to the testing of shale oils some of the methods the Bureau of Mines uses for testing petroleum. The methods employed by the Scottish shale-oil manufacturers were also studied, but most of them have been superseded by those described in this bulletin, which give more comprehensive and accurate results and employ more convenient apparatus. This paper is presented, therefore, as a manual of apparatus and methods that the bureau has developed for work on oil shale and found satisfactory for routine tests and for research. Explanation and discussion of the principles underlying the methods of testing are included wherever necessary for a clearer understanding.

Jan 1, 1926

By R. L. Grant

During the last decade or more , experimental research on commercial detonators used for initiating the detonation of dynamite and other high explosives has led to important improvements . Developments , especially in the United States , have been directed toward improvement in the construction of detonators to make them safer to manufacture and use . More suitable and safer initiating charges also have been found . Although for many years mercury fulminate was unrivaled as the initiating charge for dynamite , during the last decade it has been replaced to a large extent by less sensitive , more efficient, and cheaper combinations of ignition , priming , and base charges . Commercial detonators were once of relatively simple construction and almost universally identical . Today they are technically complex, with special nodifications for particular uses ; they have developed along different lines n various countries and even among the several manufacturers within any one country .

Apr 1, 1943

By J. W. Paul

A superintendent is one who has the oversight and charge of some organiza- tion or enterprise, with porer of direction. The superintendent of a coal mine is the official who is in general charge of conducting the operation of the nine for the purpose of producing coal; he is accountable to his superiors for all matters that relate to the cost of production and safety in operation, ed under him are all the underground officials and other personnel making up the mine organization. The responsibility of the superintendent covers all the principal phases of mining, purchases of materials, issuance of supplies, accounting, and upkeep of the property and equipriont. In a broad sense, the superintendent must view his job as embraced under four gneral heads: (1) Construction, (2) instruction, (3) supervision; and (4) discipline. The degree of efficiency with which each of these phases of his work is conducted is a measure of the safety factor which the superintendent injects into his job. Injury to workmen and damage to property may be due to neglect of one of these general headings; as for example in the collapse of a scaffold there has been faulty construction which may be found upon investigation to have been the result of faulty instruction or lack of instruction. It may be that the condition of the scaffold was not ascertained in advance of its collapse through faulty supervision, or the discipline of the workmen had been neglected.

Sep 1, 1930

By Joseph Cervik

Gas occurs in coalbeds in an adsorbed and a free gas state. Adsorbed gas is stored in the micropore structure and its transport is governed by Fick's law. The free gas occurs in the fracture system and flows according to Darcy's law. These two modes of mass transport are interdependent. Production decline curves of coal-gas wells are of the constant percentage decline type and, thus, show no indications of flow characteristics peculiar to coal-gas reservoirs. The effectiveness of surface boreholes as a degasification scheme depends upon both good fracture permeability and a high fracture density. Conventional methods of reservoir engineering analysis are not applicable to coalbeds

May 1, 1969

By James C. Duchon

The use of extended workdays (regular shift lengths of 10 or 12 h (hour), while still maintaining a 4O-h workweek) in mining operations is attracting growing interest in the United States. There is very little doubt that extended workdays is a very popular alternative among the work force because of the significant increase in days off, including weekends, especially when compared with traditional rotation schedules of working seven straight shifts or having only one weekend off every 4 to 6 weeks. However, there are some serious concerns by management, workers, unions, and various governmental policymakers that working 10-or 12-h days may create an added risk of accidents and health problems. The U.S. Bureau of Mines reviewed the literature studies related to the safety and performance issues of extended workdays. This report presents a summary of those findings. The studies examined in this review are divided into three sections: (1) laboratory, (2) field, and (3) accident and injury analysis. In general, results are inconclusive. Studies have shown both positive and negative effects. It is concluded, therefore, that in industries such as mining where accidents are a serious concern, special measures and evaluation in the use of extended workdays be considered.

Jan 1, 1994

By R. T. DeWoody, W. C. Miller, W. Chester

Studies were made to determine the effect of the shape of a pneumaticrock- drill exhaust muffler on its efficiency, and the origin and reduction of exit noise from the mufflers. Tests of mufflers of three different shapes proved that the shape is not critical and that a muffler could be incorporated into the shell of the drill. Petal diffusers are beneficial in reducing exit noise but add another projection to the machine. Increasing the number of exit openings while maintaining the same area of exit opening has a markedly beneficial effect on the exit noise and appears to be the most satisfactory treatment.

Jan 1, 1964

By R. J. Kuczynski

The U.S. Bureau of Mines Reno Research Center investigated, developed, and patented a high-temperature cyanide leaching process for recovering platinum-group metals (PGM) from automobile catalysts. A batch pilot plant was constructed at the center and operated to demonstrate this technology to industry. Approximately 1,600 kg of used pellet, monolith, and metal support catalysts containing 1,700 g (54 tr oz) of PGM was processed. Forty-five-kilogram batches of used catalysts were leached with sodium cyanide solution at 160°C for 1 h in a countercurrent processing sequence. This selectively dissolved the PGM. Average extractions from the used pellet catalyst were 96 pet Pt, 95 pct Pd, and 73 pct Rh. Average extractions from the used monolith catalyst were 84 pct Pt, 81 pct Pd, and 66 pet Rh. Heating the pregnant leach solutions to 275°C for 4 h destroyed the PGM-cyanide complexes, causing over 99.7 pct of the PGM to precipitate from solution. The PGM precipitate was predominantly a metallic powder concentrate, typically analyzing greater than 50 pct PGM. Heating destroyed the cyanide to less than 0.2 mg/L free and total cyanide. Both the pellet and monolith residues were evaluated for disposal using the toxicity characteristic leaching procedure developed by the U.S. Environmental Protection Agency.

Jan 1, 2010

By L. J. Douglas, A. G. Kim

Methane and other hydrocarbon gases, byproducts of coalification, are emitted from coal at widely varying rates and often present ventilation problems during mining. The air in some coal mines apparently contains no methane. To determine if coals from mines which had no history of detectable gas emission contained adsorbed methane, samples of coal at the shaft bottom and at an active face were obtained and placed in sealed metal cylinders. The atmosphere around the coal was sampled and analysed by gas chromatography. Methane, ethane, ethylene, propane, propylene, and butane were found to have been desorbed from these coals. Hydrogen and helium were also detected. An estimate of the amount of residual gas per ton of coal indicated that coal samples from the active face generally contained more adsorbed gas than coal samples obtained from the shaft bottom, although in both instances the total amount of gas was relatively small.

Jan 1, 1973

By Robert T. Langland

The Bureau of Mines, at its Denver, Colo., research center, has developed a computer program to solve nonlinear regression problems. The program is written in a general form so that, regardless of the functional relationship assumed, the unknown parameters may be evaluated by the Newton-Raphson method of iteration. Variances and covariances of the parameters are derived, based on the propagation of errors. A creep function is established from shale test data as an example of program utility. Program accuracy is compared to the accuracies of other programs in present day use.

Jan 1, 1974

High resolution seismic refraction tomography has proved to be a useful tool to effectively estimate depth of blast induced damage in a mine face. Excavation blast damage can be as shallow as 1 to 2m and requires resolution at a fraction of a meter for effective imaging. We used an accelerometer with flat frequency response to 1000Hz to record data at spacings of approximately 0.25 to 0.5m along mine walls. First arrival times from the seismic data were used to produce P-wave velocity tomograms. The tomograms show transition from low velocity zones to velocity associated with competent rock. We interpret the low velocity zones to indicate residual fracturing from blasting. Experiments on a concrete test block and at two underground mine locations give results that are consistent with fractured rock transitioning to competent rock. Our method can be applied efficiently in an underground environment to provide continuous velocity information with depth into a mine wall over a span of approximately 10m.

Jan 1, 2009