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By A. E. Wells

A critical study of the wet Thiogen process for extracting sulphur from the smoke of smelters is one of several investigations related to the general smelter-smoke problem that are being conducted under the direction of the Bureau of Mines. Part of the work done in the pyrometallurgical section of the cooperative metallurgical exhibit of the Bureau of Mines at the Panama-Pacific International Exposition during 1915 related to this investigation, and at the expiration of the exposition, the work was continued in the labora- tories of the Bureau of Mines in the Hearst Memorial Mining Building of the University of California, Berkeley, Cal., where a mining experiment station of the bureau has been established under the cooperative agreement with the University of California. Early in the spring of 1915, when plans were being made to co- operate with several metallurgical interests, the Thiogen Co. proposed to the Bureau of Mines that, along with the studies of various pro- posed methods for eliminating sulphur dioxide from smelter smoke, there should be included a study of the wet Thiogen process. In the study as outlined it was proposed to determine whether it would be technically and commercially feasible to use the, process for the recovery of elemental sulphur from the sulphur dioxide in waste smelter gases. Although there had been no large-scale work with the process, either in the laboratory or at a smelter, representatives of the metallur- gical and mining industry had shown considerable interest in the proposed method, and the desire had been expressed that a better knowledge of the possibilities of the process should be obtained. Thus, cooperation with the Thiogen Co. seemed justified by the in- terests of the metallurgical industry, and by the conservation promised by the recovery of a product of market value from what is otherwise a waste, and in some instances a serious nuisance. In accepting the responsibility for directing this investigation, the officials of the Bureau of Mines were necessarily free to conduct the work in the manner they considered necessary to determine the facts. It was also understood that any information obtained was to be made available to all who might be interested and might be printed in a Bureau of Mines report. To cover the cost of laboratory equipment and supplies, and the payment of salaries of assistants, other than Bureau of Mines employees, the Thiogen Co. in May, 1915, deposited with the cooperative metallurgical exhibit fund a sum considered sufficient to warrant starting the laboratory investi- gation. The origin and organization of this fund has been described by Clevenger and the author." In outlining the program for this investigation it was hoped that ultimately a small complete plant would be erected and the investi- gation center around the operation of the plant. However, pre- liminary to the erection of the plant, a laboratory study of the proc- ess was considered necessary, as the technical features of the process could be determined, it was believed, as satisfactorily on a smaller scale as on the scale first proposed. However, it was realized at the time that it would not be possible to determine so satisfactorily or definitely the commercial possibilities of the process on the scale of work adopted as in the larger operating plant. With this fact in mind it was planned that, if the study of the technical features on a laboratory scale gave sufficient promise of the process being commer- cially feasible, an operating unit should, if possible, be constructed later, and that more definite information concerning the commercial prospects should be determined. The investigations were started in June, 1915. In June and July work was confined entirely to small-scale laboratory tests, in which a careful study of the chemical reactions involved was made. In August, tests on a larger scale were started, and these were con- tinued until December, small-scale tests being made at the same time. On December 1, 1915, all work on the Thiogen process was discon- tinued temporarily, as the close of the exposition necessitated moving the laboratories. Work on the Thiogen process was started again in January, 1916, in the laboratories of the new mining experiment sta- tion at Berkeley, Cal., and was continued during the spring of 1916 until a point was reached where it was felt that the essential parts of the process had been carefully covered, and that some definite state- ments concerning the technical features and possibilities of the process, as given in this report, were warranted.

Jan 1, 1917

By Bernard Porter

Differential thermal analysis measurements were used to characterize a phase diagram for the KF-YF3 system at compositions between 0 and 60 mole-percent YF3, A congruent melting point compound was observed at 3KF?YFs, which melts at 965°±5° C and undergoes solid-state decomposition at 725°±2° C. One peritectic and two eutectic compositions are also defined.

Jan 1, 1969

By Dana Reinke, Launa Mallett

Interest in training evaluation in the mining industry was piqued with the promulgation of Title 30, Part 46, of the Code of Federal Regulations. Under Part 46.3, a training plan is considered to be approved if it contains certain information, including “The evaluation procedures used to determine the effectiveness of training.” The present paper is a broad overview of training evaluation and is intended to give trainers and decision-makers a framework for planning or assessing training evaluation strategies. It discusses questions to consider when starting an evaluation plan, Kirkpatrick’s model of evaluation categories, and various ways to collect data. It does not provide detailed instructions on how to develop evaluation methodologies, but reviews topics to consider when creating an evaluation plan. Training evaluation is a term that has many different meanings: assessing the quality of a course, effectiveness of materials used, teaching style of an instructor, or the comfort of a classroom. An evaluation can be done informally over lunch or with highly structured data-gathering tools. It can produce results that are useful to trainers, program administrators, corporate decision-makers, or no one. The key to a worthwhile evaluation is clearly defining why the evaluation is being conducted. Once the purpose is defined, planning the evaluation strategy can begin. For an evaluation to be effective, it should be incorporated into the development of the training activity itself. The training evaluation worksheet at the end of this paper can be used to guide evaluation planning.

Jan 1, 2002

By T. Bajpayee, L. Prosser, A. Iannacchione, G. Esterhuizen

Reducing the number of roof fall injuries is a goal of the NIOSH mine safety research program. Central to this effort is the development of assessment techniques to help identify the nature of the risks associated with working under potentially hazardous roof conditions. This paper discusses a method to determine the roof fall risk using a qualitative risk-analysis technique. The ability to determine roof fall risk has been a long-standing goal of safety professionals and could provide the kind of information needed by on-site personnel responsible for worker safety to mitigate roof fall injuries.

Provide a method of detecting and locating miners trapped underground following a mine disaster. Approach Develop a surface deployed system which senses the vibrations caused by a trapped miner pounding on the roof of the mine and effectively determines the miner's location. How It Works If trapped underground, a miner would strike the roof of the mine with any implement at his disposal. This pounding causes vibrations in the ground which are transmitted to the surface where they are sensed by receiving transducers called geophones. Multiple geophones are positioned together for noise cancellation purposes in a form called a subarray. Seven

Jan 1, 1981

By R. W. Crocker, H. H. Clark

The purpose of the investigation discussed in this bulletin, one of a series dealing with the use of electricity in mines, was to study the various means and methods used to confine the flashes that occur when a switch carrying electric current is opened. The flash result- ing from the opening of a 250-volt direct-current circuit carrying more than half an ampere will ignite explosive mixtures of mine gas and air. An equally dangerous flash may be produced by even less cur- rent from a 500-volt circuit. Few mine electric circuits carry less than half an ampere when in use. The need of protecting the switches of such circuits in places where gas is likely to be present is therefore obvious. Two general methods have been proposed for preventing switching flashes from igniting gas surrounding the switch. One method is to inclose the switch in a casing provided with openings that are covered with wire gauze or otherwise designed and equipped for preventing the passage of flames from the interior to the exterior of the switch casing. Switches so protected are called explosion-proof switches. The second method is to immerse the switch contacts in oil to a depth sufficient to quench any flash that may occur when the switch is operated. Switches so protected are called oil switches. The success of the first method of protection depends upon the proper design and construction of the switch casing. It is essential to the successful operation of the second method that the switch contacts be surrounded by the proper kind of oil in good condition. There are several ways in which an oil switch may be deprived of its protective feature. The oil tank may not be filled or, if filled, the oil may leak out or be spilled. The oil tank may be removed (in some designs) and not replaced or through neglect the condition of the oil may become such that it is no longer an efficient protection. While such contingencies are not likely to occur, and although oil switches may be so designed that the loss of oil is not probable, nevertheless, as compared with oil switches, explosion-proof switches seem to

Jan 1, 1913

Generate less respirable dust during mining by reducing the clogging and downtime of the water sprays on mining machines, especially on continuous miners. Approach An improved filtering system, having commercially available components, has been designed and tested. How It Works The improved filtering system shown opposite is mounted on the mining machine, where It traps particles of coal and pipe scale which cause most clogging of the water sprays. Water entering the system first flows through a ?Y" strainer, which screens out particles larger than 1/8 inch diameter. Next, the water whirls through a small hydrocyclone. Most of the remaining smaller particles are removed and pass Into the accumulator compartment built into the hydrocyclone. The water also flows through a final filter. This filter catches particles that might pass the hydrocyclone, especially during water spray start-up and shut-down, when the speed of the water flow is not sufficient for

Jan 1, 1976

By D. R. Tesarik, F. M. Jones, J. B. Seymour

As part of safety and stability studies at three underground mines in the United States, researchers installed earth pressure cells and embedment strain gauges in cemented rockfill to measure stress and strain changes as mining progressed and the rockfill was loaded. Data from these instruments were used to calculate the in situ modulus of the rockfill for two of the mines. A three-dimensional numerical model of a cemented rockfill cap was validated with data from extensometers anchored in the mine roof and sill; this model was then used to estimate deformation modulus at the third mine because the earth pressure cells and embedment strain gauges recorded negligible changes. Rockfill binder used at these mines ranged from 4 to 8 per cent of the dry components by weight, the water-to-cement ratio was from 0.42 to1.0, and the largest aggregate size in the three mixes ranged from 5 to12 cm (2 to 4.7 in). The range of the calculated in situ deformation modulus values was large, but as expected, it was bracketed by modulus values for cemented tailings and roller-compacted concrete with similar cement contents and water-to-cement ratios. Dans le cadre d’études sur la sécurité et la stabilité de trois mines souterraines situées aux États-Unis, les chercheurs ont installé des palpeurs de pression des terres et des extensomètres d’encastrement dans les remblais cimentés afin de mesurer les variations relatives à l’effort et à la déformation des terrains durant l’exploitation minière et le chargement du remblai. Les données recueillies à l’aide de ces instruments ont servi au calcul du module in situ du remblai dans deux de ces mines. Le modèle numérique tridimensionnel de la semelle d’un remblai cimenté a été validé à partir des données recueillies par les extensomètres ancrés dans la voûte et dans la semelle de ces mines; ce modèle a ensuite été utilisé pour estimer le module de déformation à la troisième mine, étant donné que les palpeurs de pression des terres et les tensiomètres enfouis avaient relevés des variations négligeables. La matière d’agrégation de l’enrochement utilisée dans ces mines comportait entre 4 % et 8 % des composantes sèches par poids; le rapport eau-ciment se situait entre 0,42 et 1,0; et la taille des agrégats les plus gros dans ces trois mélanges était de 5 cm à 12 cm (2 po à 4,7 po). L’écart entre les valeurs calculées des modules de déformation in situ était grand, mais comme on s’y attendait, cet écart a été compensé par les valeurs modulaires des résidus cimentés et du béton tassé au rouleau avec des teneurs en ciment et des rapports eau-ciment semblables. [Als Teil der Sicherheits- und Stabilitätsstudien an drei Bergwerken in den Vereinigten Staaten von Amerika installierten Forscher Erddruckgeber und Einbindungsdehnungsmesser in zementierter Steinschüttung, um Spannungs- und Dehnungsveränderungen während der fortlaufenden Bergarbeiten und der Belastung der Steinschüttung zu messen. Daten von diesen Instrumenten wurden dazu verwendet, das In-Situ-Modul der Steinschüt-ung für zwei Gruben zu berechnen. Ein dreidimensionales numerisches Modell einer zementierten Steinschüttungsschwelle wurde mit den Daten von den im Grubendach und in der Schwelle verankerten Extensometern validiert; dieses Modell wurde dann dazu eingesetzt, um das Deformationsmodul in der dritten Grube zu schätzen, da die Erddruckgeber und Einbindungsdehnungsmesser nur geringfügige Messabweichungen feststellten. Das in diesen Gruben verwendete Steinschüttungsbindemittel variierte zwischen vier und acht Prozent an Trockenkomponenten nach Gewicht, der Wasser-Zementfaktor betrug zwischen 0,42 und 1,0 und die größte Zuschlagstoff-größe in den drei Mischungen schwankte zwischen fünf und zwölf Zentimetern. Die Reichweite der berechneten Werte des In-Situ-Deformationsmoduls fiel etwas breit aus, aber es fand erwartungsgemäß eine Klammerung der Modulwerte zwischen den Zemen-trückständen und dem durch Walzen verdichteten Beton mit ähnlichem Zementanteil und Wasser-Zementfaktor statt.]

By R. L. Rankin

The program objective was to conduct surveys of respirable dust concentrations in coal mining operations at locations outby the working face. The results of these surveys were directed toward 1. identifying outby dust sources, 2. evaluating the severity of the major dust sources, 3. establishing dust sampling frequency, 4. establishing dust sampler locations, and 5. assessing the? areas of influence of the dust sources. The study included dust sampling of only nonhigh risk personnel and areas at six dif-ferent mines. Thirteen continuous mining, four longwall and two conventional mining sections were sampled. The severity of outby respirable dust sources such as load points, runways, dump points, beltways, transfer points and main haulage operations were characterized and areas within the mine were ranked according to severity. Information on engineering controls was also acquired. Guidelines for implementing a dust sampling program are presented and include sampler locations, ventilation surveys, dust surveys, effects of shift-to-shift variations, and sampling frequency.

Jan 1, 1980

By H. F. Yancey

A relatively large proportion of the coal produced 1n the State of Washington, especially in the coking coal areas is of fine size; hence washing by means or coal-washing tables to reduce the ash content is commonly practiced. For this reason the program of research in coal washing conducted jointly by the U. S. Bureau of Mines and the College of Mines, University of Washington, has given special attention to the mechanism or the separation of coal from its impurities as effected by the coal-washing table with the object of increasing its efficiency. Previous work has evaluated the role of stratification the influence of size, specific gravity and respective shapes of particles in the feed, and the affect of hindered-settling classification of the feed prior to tabling.

Jan 1, 1931

By Floyd D. Everett

The J. B. fluorite deposit is in the Washington mining district, southwestern Beaver County, Utah (fig. 1). Fluorite outcrops were found during 1942, and three lode claims wore located. Little work was done on the property until October 1943, at which time the Bureau of Mines started development to determine the subsurface extent of the fluorite mineralization exposed at the surface. The most prominent rocks in the J. B. mine area are porphyries, which vary considerably in composition. Dacite porphyry appears to be the most common host rock for the fluorite-quartz-calcite lenticular masses. The dacite porphyry in the area is highly brecciated over a strike length of more than 1 mile. Fluorite deposits in the brecciated zone cover a strike length of approximately 400 foot. The fluorite lenses range in length from 40 to 200 feet and in width from 4 to 10 feet (fig. 2). The Bureau of Mines work on the J. B. property was started in October 1943 and completed in October a year later. The work consisted of surface trenching by bulldozer and hand methods, shaft sinking, drifting, and crosscutting. Eleven trenches totaling 1,800 linear feet were excavated. An inclined shaft was sunk to a depth of 105 feet, and from thin shaft 577 feet of drifts and crosscuts were driven to outline the extent of the mineral deposit (fig. 3). Two hundred ninety-seven samples were taken in the surface trenches and underground workings. The locations of the samples and analyses arc shown in accompanying figures and tables. Results of metallurgical tests comprise the concluding section of this report.

Jan 1, 1950

New Continuous Personal Dust Monitors (CPDM) submitted to NIOSH for approval to sample coal mine dust must accurately measure respirable coal mine dust in mine environments. There are two steps in the process which may be done in any order. The manufacturer is required to submit the results of a comparative underground coal mine dust sampling study, where the candidate CPDM is compared to an approved coal mine dust sampling device (currently the Coal Mine Dust Personal Sampling Unit (CMDPSU)). This testing shall follow the guidelines outlined below and shall demonstrate through weighted regression analysis that the mean coefficient of variation with bias correction is equal to or less than 12.8%. The other step involves laboratory testing to determine the electronic and environmental stability. This testing must be conducted by a private, commercial, academic or other laboratory approved by NIOSH.

Jan 1, 2009

By L. D. Johnson

On a project which is to develop a system to suppress coal dust explosions, a facility has been built and several devices tested. The facility is a 317-foot, 4.5-foot diameter shock tube and to date 53 tests have been carried out with methane-air and methane/coal dust-air as the explosive mixtures. Suppression of slowly propagating (up to 300 ft/sec) flame fronts has been successfully carried out on two tests using the dry chemical extinguishing agent Purple K. Delivery of the material directly into the flame front Seems to be required if effective suppression is to be accomplished.

Jan 1, 1972

Ohio has an estimated 46 billion tons of coal beneath 12,000 square miles of the eastern third of the state. Recoverable coal reserves within this vast area are estimated at 21 billion tons, 3.2 billion tons of which have been mined since 1800. Ohio is the eleventh-largest coal- producing state in the nation and ranks third nationally in coal consumption. Coal resources in Ohio lie in as many as 60 identifiable coal seams along the northwestern flank of the Appalachian coal basin. Except where interrupted by minor faults and erosional discontinuities, these rocks dip gently and uniformly to the east, simplifying the mining methods needed to extract the coal. Fourteen of Ohio's 60 coal seams are considered to be important, although only a small number of seams are currently being mined. Ohio first enacted a surface coal mining law in 1948, requiring in part a $100 per acre reclamation bond. Ohio progressively strengthened its surface mining law in 1949, 1955, 1959, 1961, 1965,1972,1975,1978, and 1981. At the time of its enactment, Ohio's 1972 mining law was one of the most stringent in the country. This law also created a state coal severance tax of four cents per ton to be used for abandoned mine land reclamation. Ohio received primacy to regulate the surface coal mining operations within the state August 16,1982. Its Abandoned Mine Land Program was approved on the same date.

Jan 1, 1992

By John Paul Gries

During World. War II, when the curtailment of imports led to an unprecedented demand for domestic mica, beryl, spodumene, and other pegmatite minerals, the Bureau of Mines and the Geological Survey entered upon a program designed to expedite mining of these minerals from the Black Hills area of South Dakota. The program involved napping, sampling, and drilling of many pegmatite dikes in the southern portion of the Black Hills and beneficiation conducted in the field and in the Bureau of Mines laboratories at Rapid City, S. Dak., Rolla, Mo., Salt Lake City, Utah, and College Park, Md. This report describes the occurrence and sampling of the Beecher No. 2 pegmatite, which was investigated as part of the general pegmatite study in South Dakota. Investigation of the Beecher No. 2 pegmatite was started on November 20, 1943, and terminated in the spring of 1944. During this period, the Bureau of Mines took a series of trench samples across the pegmatite at the surface for grain-count studies and chemical analyses. The Geological Survey mapped the geology of the deposit after it was exposed by trenching and stripping.

Jan 1, 1950

By Harold W. Lipper

BUREAU OF MINES helium plants produced a. record-breaking 477 million cubic feet of this essential element in 1959. The supply of helium was less than the demand before operations were resumed at the Navajo plant in July and begun Sit a. new plant at Keyes, Okla., in August. Helium was in abundant supply after August, and the informal allocation system which had been in use intermittently since 1955 was discontinued Delivery of 26 new tank cars in August and September increased the total in the tank-car pool to 163. Defense and space agencies and the Atomic Energy Commission continued to use more helium in their operations and research.

Jan 1, 1960

By G. S. Scott

It is sometimes desirable to know what changes in sizing characteristics would appear in screened coals if screens of different - size openings than those employed had been used . This report is concerned entirely with the application of the Rosin- Rammler law to a solution of this problem .

Dec 1, 1943

By N. Kumar Kittusamy

By Leonard Greenburg

The analytical procedure necessary when using this new impinger•bubbler eil)paratus is almost identical with that em:r;,loyed with the Palm0r a:pp8.ratua. As sugar is not employei, the new apparatus por.;sesses the advantage over the eug.r tube method in having vsry low control errors, being, therefore, much simple in laboratory manipulation during analysis.

Aug 1, 1922

By A. Sainato, S. J. Kravits, G. L. Finfinger

This report describes a project conducted by the Bureau of Mines in which the accurate directional drilling of a borehole was demonstrated with the objective of intercepting a designated target. The project was conducted at Navajo Dam in northern New Mexico at the request of the Bureau of Reclamation. Borehole survey and drill logs are provided in an appendix. The trajectory of the demonstration borehole was designed to intercept a 5-ft-radius target at the final or "punchout" distance of 885 ft. The elevation of the borehole at this distance was within the target; the borehole punchout coordinates were 8.81 ft southwest of the target. As a result of the demonstrated accuracy, the Bureau of Reclamation has contracted the accurate drilling of boreholes as long as 600 ft from the inside of a short tunnel, to control water seepage in the right abut- ment. This resulted in a substantial cost savings compared to the orig- inal plan of constructing a longer tunnel and drilling 150-ft boreholes.

Jan 1, 1987