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By Alla D. Mah

The energies of combustion of zirconium carbide and hafnium carbide were measured by combustion calorimetry and the heats of combustion and formation. of zirconium carbide and hafnium carbide were derived . The results are-- ZrC AH298.15 ( combustion) = -308.60 ± 0.55 kcal /mole , AH298.15 ( formation) -47.0 ± 0.6 kcal /mole , AH298.15 = HfC (combustion ) = -306.08 ± 0.20 kcal/mole , AH298.15 ( formation) -52.3 ± 0.4 kcal /mole . = INTRODUCTION This report contains the results of calorimetric measurements to obtain the heats of formation of zirconium carbide ( ZrC) and hafnium carbide ( HfC) . The work was conducted as part of a Bureau of Mines program for determining the heats of formation of oxides , carbides , and nitrides by combustion calorimetry . Combustion calorimetry is one of the most precise calorimetric techniques . The chief obstacle to obtaining accurate heat of formation values for carbides , and the chief reason for the variation in the results of different investigators , is the lack of purity of the carbide samples . Corrections for impurities always involve assumptions which lead to uncertainties . In general , a large impurity correction is accompanied by a large uncertainty in the final result .

Jan 1, 1964

By Paul C. Turner

The U.S. Bureau of Mines, through an Interagency Agreement with the U.S. Army Tank-Automotive Command (TACOM), has successfully developed a steel expendable pattern casting process (EPC) for the manufacture of armorplate. The new armor is lighter and more ballistically effective than conventional rolled homogeneous armor (RHA), and costs less. An applique armor spinoff from the program was field-tested during the Gulf War. The applique armor withstood direct impacts from enemy munitions without failure.

Jan 1, 2010

By J. M. Kuchta

The Bureau of Mines investigated four simulated coal gob fires to obtain a more reliable data base for defining the state of a sealed mine fire and to evaluate the performance of various fire detectors. The fires were conducted in a multiple-entry section of the Bruceton Experimental Mine by heating 4,000 to 21,000 pounds of rubblized bituminous coal to ignition and monitoring the temperature, gas emissions, and smoke under ventilated and sealed combustion conditions. Product gas concentrations depended upon the coal bed size, coal temperature, heating rate, and oxygen concentration or ventilating condition but varied little after the fires were sealed. Expressions are given that define the temporal variation of CO and O2 after sealing when the coal temperature decreased rapidly. The CO/C02 ratio is a more sensitive fire indicator than the CO/?02 ratio, although the latter is universally used for detecting the incipient state of a coal fire. In comparison, the Jones-Trlckett ratio [ CO2 + ¾ CO ? ¼ H2 ?O2] is less reliable for this purpose. The best detector for determining the state of a mine fire after it has been sealed was a prototype submicrometer smoke particulate sensor. Limitations of the various detector systems are also discussed.

Jan 1, 1982

By W. E. Young

This paper describes operations of the Chief Consolidated Mining Co. at the Chief mine in the Tintic district, Juab County, Utah, where the outstanding problem is water control; the unique pumping methods employed are featured in this report. The ore bodies in this district occur as long, narrow shoots along fault fissures, usually in the Bluebell dolomite of Ordovician age. Oxide ores predominate above the 1800 level, which is also the natural water level. Sulfide ores containing lead, zinc, silver, and gold extend below the 1800 level. The mine is developed by vertical shafts and winzes, from which drifts are driven to the ore bodies. In the lower levels of the mine these drifts extend long distances from the shafts or winzes because of the relatively low dip of the ore shoots. The mine has been worked to the 2800 level and the 18-411 winze extends to the 3080 level.

Jan 1, 1958

By Robert V. Spencer

"This report describes an examination and preliminary exploration of the Magnet Cove Rutile Co. property in Hot Spring County, Ark. The company in 1944 was producing titania for use in-the welding-rod and metallurgical industries but later ceased operations. The deposit appeared to contain potential reserves of rutile ore, and the Bureau of lanes in 1945 conducted an examination designed (1) to obtain samples for ore-dressing tests and (2) to gather information regarding the grade, character, and size of the deposit. This report presents the data obtained by geologic mapping, geophysical surveying, churn drilling, and core drilling. Beneficiation tests are being made at the Bureau of Mines Rolla, No. station, on the samples taken and will be discussed in a later report.The Magnet Cove operation had been called to the attention of the Bureau of Mines, and in view of the potential reserve of titanium-bearing material, it was decided to obtain samples for ore-dressing tests. Churn drilling was selected as a means of obtaining representative samples, and geologic mapping and geophysical surveying were done to throw more light on the nature of the deposit. Subsequently, a few holes were core-drilled.The property contains the NE1/4, W1/2 fractional NW1/4 and 82 acres of the N part of SE of sec. 18, and -29 acres of the SW1/4 NW1/4 sec. 17, all in T. 3 S., R. 17 W., Hot Spring County, Ark. The mine and mill are about 1 mile by graveled road northeast of U. S. Highway 270, a paved road connecting Malvern, 10 miles south and Hot Springs, 12 miles west. The area is served by two railroads, the Missouri Pacific, which passes through Malvern and Hot Springs and the Chicago, Rock Island & Pacific,,has a line connecting Malvern and Hot Springs an passes about 2 miles south of the property. A natural-gas pipe line and an electric power line reach the property."

Sep 1, 1946

By Donna L. Anderson

This U.S. Bureau of Mines report discusses the status of a laser-based guidance system to provide position and heading feedback and closed-loop control of tramming maneuvers for a continuous mining machine. The system has been developed and tested at the Bureau, and is now being prepared for underground experiments. The system hardware includes laser scanners, a sensor communication network, and host computer hardware. The system software includes a position and heading computation module and a tram control module. The description of the software includes discussions of laser data acquisition, error compensation methods, position and heading determination, safety checking for continuous miner tramming, and closed-loop tram control. The accuracy of the laser scanner's data, the reliability of the lasers in a dusty environment, and the system's accuracy on tracking the position and heading of the continuous mining machine are shown in the results of experiments performed at the Bureau. Conclusions are stated based on these experimental results, and further work to improve the system performance and prepare for underground testing is discussed.

Jan 1, 1990

By W. G. Hopkins

The development of systems for location of miners who have become entrapped following a mine disaster has been one of the major research goals in the Bureau of Mines. This study details the preliminary development of such a system. Current technologies for locating trapped miners from the surface are either simple direction finders or time difference pulse systems that have accuracy limitations. Developing technologies using full vector field measurements at several receiving points are currently being studied. The necessity of measuring field strength with great accuracy can be a drawback in these systems. A system that operates with continuous wave radio signals, whose phase differences can be measured accurately even in weak signal conditions, greatly improves the location accuracy. A microcomputer would be used in conjunction with the system, to gather and manipulate the data to automatically pinpoint the location of the trapped miner. Comparison of this system with existing technology indicates a favorable accuracy/complexity ratio for the phase difference of arrival technique.

Jan 1, 2011

By W. Beckering

In characterizing tars obtained by the low-temperature carbonization of North Dakota lignite, infrared spectra have been an invaluable aid in both qualitative and quantitative examination. Quite, early in the tar-research program of the Federal Bureau of Mines it became evident that the small number of published spectra available for hydroxy-aromatics would be inadequate for comparative purposes when dealing with the wide range of compounds present in coal tar; therefore, compiling a catalog of spectra was begun as a continuing part of the tar program. Because these spectra should be valuable to other investigators in this and related fields, they are being presented in these reports. This supplement to the original publications presents the spectra (figs, I to 32), representing 32 compounds, largely phenolic materials. The major problem of this project has been the availability of materials for examination. Most of the compounds included in this supplement were synthesized at the Bureau of Mines Lignite Research Laboratory. Some were obtained from commercial sources, whereas the compound 2'-hydroxy-l-phenylnaphthalene was synthesized at the Bureau of Mines laboratory in Bruceton, Pa. The spectrum of 2-ethyl-4-methylphenol, figure 32, is a correction of the spectrum presented as figure 26 in the original reports

Jan 1, 1961

By W. C. McBee

A family of modified-sulfur cements has been developed by the Bureau of Mines for the preparation of construction materials with improved properties. Various types of sulfur cements were prepared by reacting sulfur with mixtures of dicyclopentadiene (DCPD) and oligomers of cyclopentadiene (CPD). Durable cements were prepared with structural characteristics ranging from rigid to flexible. These cements were used to prepare corrosion-resistant materials for use in a wide variety of industrial applications where resistance to acidic and salt conditions is needed. These materials were prepared as rigid concretes, flexible pavings, spray coatings, and grouts. Production of modified-sulfur cements in a commercial-size plant was demonstrated.

Jan 1, 1981

By Oliver C. Ralston

Nonmetallic technologic investigations of the U. S. Bureau of Mines are headquartered at experiment stations in three widely separated localities of the United States. During 1936, the Nonmetals Division of the Technologic Branch was formally set up by combining the direction off the work of these three experiment stations under one administration. The New Brunswick (N.J.) station which in the past has been known as the Nonmetallic Minerals Experiment Station, is henceforth to be at College Park, Md., as part of the Eastern Experiment Station, and its principal activities will be related to the nonmetallic resources of the Eastern and New England States.

Jan 1, 1937

By W. E. Wallace, B. L. Razzaboni, P. Bolsaitis, M. J. Keane

"Therma1 and chemical treatment of respirable size silica dusts samples is shown to induce marked changes in their hemolytic activity. The cytotoxicity of crystalline a-quartz (Min-U-Sil), and fumed silica (Cab-0- Sil) particles, as measured by a hemolytic activity protocol, is decreased by calcination and can be related to the dehydroxylation of the surface. The hemolytic activity of P-cristobalite particles of respirable dust si7.e was also determined and found to be lower than that of a-quartz. The change in the surface structure resulting from thermal treatment is detectable by photo-acoustic infrared spectroscopy and zeta-potential measurements. The absorption band in the 3200-4000 cm-1 frequency region of both Cab-0-Sil and MinU- Sil disappears upon heat treatment while a sharp band, identified with single silanol groups, at 3750 cm-1 increases in intensity. The zeta potential-pH profile, in the pH range of 4.0-7 .0, of the calcined, siloxane surfaced particles is more negative than that of material with a silanol surface.The cytotoxicity of the crystalline and fumed silica dusts was also found to be strongly dependent on particle size. Fumed silica of large surface area (small particle size) exhibits an initial increase in hemolytic activity upon calcination. This result confirms other experimental observations pointing to a particle size of maximum toxicity. INTRODOCTIONThe toxicity of silica and other mineral particles, as manifested by their role in inducing pneumoconiosis, fibrosis, silicosis and other pulmonary disorders is largely traceable to the characteristics of particle surfaces and to particle morphology. The great wealth of data on the physical and chemical properties of silica is still insufficient for a comprehensive understanding of the specific parameters to be associated with fibrogenic activity and, correspondingly, with the optimum means for characterizing and quantifying the toxicity of dusts, and the design of possible preventive or therapeutic methods.The great diversity of parameters that have been proposed and tested for correlation with cytotoxicity suggest that more than one mechanism may be involved in the fibrotic activity of silica particles. The crystalline structure of the material (more active tridymite versus less active crisobalite and passive stishovite), freshly formed surfaces and free radicals associated therewith, silicic acid adsorbed onto silica surfaces, the concentration of hydroxyl groups at silica surfaces, particle size and morphology, among other properties, have been investigated and found to conelate in tests of cytotoxicity."

Jan 1, 1990

By Lloyd Williams

A vertical air shaft in the Birmingham, Ala., iron district was sunk with a circular cross section and lined with concrete at a relatively low cost to provide needed ventilation for an iron-ore mine. The method of sinking the shaft is described, and the costs are stated in mar-hours with a descriptive list of equipment and a statement on the size and use of temporary buildings. Preparation began May 2, 1955, and the shaft was completed at a depth of [680] feet by September 22, 1956. By October 1956, all temporary building and [aft]-sinking equipment had been removed. The total direct-labor cost for the operation, including preparation and dismantling, was 50,700 man-hours, or 30.2 man-hours per foot. Total rock and dirt removed amounted to 17,523 cubic yards (in place), and the shaft lining required 4,635 cubic yards of concrete to form a circular air shaft with an inside diameter of 16 feet.

Jan 1, 1960

By G. W. Birge

Carbonizing properties of the principal coalbeds of Elk, Clarion, Jefferson, Clearfield, and Centre Counties, Pa,, are described in this Bureau of Mines report, Twenty-six samples, representing the Upper Freeport, Lower Freeport, Upper Kittanning, Middle Kittanning, Lower Kittanning, and Brookville beds, were carbonized by the Bureau of Mines--American Gas Association (BM-AM) method, and yields of products and physical properties of cokes were determined. Expansion or contraction of the majority of the samples was measured in the Bureau of Mines sole-heated oven. Chemical analyses, agglutinating values, and free-swelling indexes are given for all samples. In this area the coals generally are characterized by high sulfur and moderately high ash content, and their suitability for metallurgical use would depend largely upon satisfactory cleaning. The samples from Elk, Clarion, and Jefferson Counties were high-volatile A bituminous In rank, whereas, most samples from Clearfield County and all those from Centre County were of medium-volatile rank. Coals from Clarion County had dry, mineral- matter-free fixed-carbon contents ranging from 56.5 to 60.3 percent and were weakly coking. With the exception of two samples which contained excessive ash, the medium-volatile coals of Clearfield and Centre Counties were strongly coking and, as indicated by sole-oven expansion results, would require blending with lower rank coal to avoid oven damage.

Jan 1, 1963

By Donald E. Redmon

This Bureau of Mines report examines the injury experience in the quarrying industry for the years 1968-69. Twenty-eight tables for each year are presented in which disabling work injuries are summarized by department, source of injury, extent of disability, part of body injured, and nature of injury. Correlative information on employment, worktime, and operating activity is also presented.

Jan 1, 1973

By J. J. Hoeppner

Accurate determination of moisture in coals of various ranks has long been a subject of intensive investigation. Excellent reviews of methods developed over many years are given by Brown (9)4/ and, with experimental comparisons, by Goodman, Gomez, and Parry (11). As pointed out in these and other writings, one of the principal difficulties in assigning absolute merit to one or another procedure is the multiplicity of conditions under which water may exist in coal and the difficulties involved in obtaining sharp separation and distinction between these classes. Gauger (10) states: Water recoverable from coal is obtained from the following sources: (1) Decomposition of organic molecules (sometimes called combined water), (2) surface adsorbed water, (3) capillary condensed water, (4) dissolved water, and (5) water of hydration of inorganic constituents of the coal.

Jan 1, 1956

By D. W. Blaylock

I. The Lower Kittaning bed is the most important bed in Clarion County from the standpoint of present production, but the Clarion bed has the largest recoverable reserve. 2. Known measured and indicated reserves in all beds, based on a minim thickness of 14 inches and 1,800 short tons per acre-foot of coal in place, are estimated at 1,210 million short tons as of January 1, 1952. Of this total, 790 million short tons is in beds 28 inches and mare thick. Areas in some beds were omitted from the estimate because available data relative to the bed characteristics are too wager for ding an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, they should be added to the total estimated reserves.

Jan 1, 1956

By John Gross

In connection with some investigations being made at '!'he Ra.re uid Precious 1ets.ls Station of the U, S. Bu.rea.u of Mines, at Reno, Nev., on the precipitation of gol'i and silver from cyanide solutions, it wa.s sug­ gested tnat the use of acetylene for this purpose be investigated, A pa.tent was iss·.ied to Fre<!.erick W. Martin and Frederick Stl1.bbs in 1900 covering the precipitation of precious metals from cyanide solu­tions by acetylene, The acetylene used in the tests described below wa3 made f'rom a. corr.:nercial cal ci \'!Z:l carbid.e, A r..umber of exper:me11. +,s rezul ted in more or lP.ss ccmplete pree;p1tatien of silver, -but 1n no case was a11Y gold precipitated. As silver acetylide, obtained by precipitatir.g the silver from an ar:::ncni'i\.Ca.l so1ut1on of silver n,. tra.te by acetylene, is yellowish white, esn:, solu'.)le in cyanide and hlghly explosive, and the pr9cip1tate ob­tain£ frcvm the cy'31lide sclutions was black, not tlubla L., cyanide and not explooive, it 'Na.s deid-,d. to ir.·.restigate the na.tur.e of the slJ.ver pre­cipit.te !rem the cy;r:iide solu·t:i.i,ns, !n prepa;.•i::lg a lge (!\,wrttity ,:f the preci-pi tte 1 t. wa, fo·und that a.fter c,:.\i;:1 ete prEc"'.pi tat ion cf the eil ver the !IOl ution con ta.ined soluble eulphic.e • Thia p:!:'O'lided a el f!W "lt·d. a.ft er apr,ropri-9.te tests the preeipita.te VIO,I proved to 'be ailver sulphide.

Apr 1, 1922

By N. F. Le] [Jaune

[ ]

Jan 1, 1923

By Forest H. Majors

"INTRODUCTION The Brutch sulfur deposits were explored by the Bureau of Mines during the spring and summer of 1944. Old workings were rehabilitated and sampled, test pits and shafts were sunk, and trenches were cut through the surface alluvium.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts prelimi¬nary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.Special acknowledgment is due S. R. Zimmerley, regional engineer, and Paul T. Allman, principal engineer, Bureau of Mines, Salt Lake City, for their supervisory aid, and to the metallurgical staff, Salt Lake City, for beneficiation of samples."

Oct 1, 1946

By Grant R. Brown

This report presents the results of a study examining the relationship between supervisor characteristics and performance in underground coal mines, The specific objectives of the research include; document tasks performed by first-line supervisors during a normal shift; explain why supervisors carry out their duties as they do: identify salient characteristics of effective first-line supervisors; and formulate criteria for selecting and developing candidate supervisors. To accomplish the study objectives, on-site observation and data collection was carried out at 13 underground mines in Illinois, Ohio, and Pennsylvania. One hundred thirty-eight first-line supervisors were observed during a full work-shift and discussions with the supervisors and the mine superintendent were held during the course of the visit. The observational data from the study provide a detailed description of what supervisors to during their shift. The report begins with an introduction discussing the problem being studied and objectives of the research. The literature related to supervisor selection is then reviewed. The following section describes the research design including data collection procedures and statistical methodology used in the study. The next sections present the analysis of mine, section, crew, and supervisor characteristics. The report concludes with a discussion of the results of the study and recommendations concerning supervisor selection and development.

Jan 1, 1987