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By D. Harrington

Approximately 2,000 persons are killed annually in the coal mines of the United States. There is no question that this number is at least double and probably treble what it should be and by all means the least excusable of the fatalities are those caused by explosions and fires. Fatalities from explo- sions and fires in coal mines are almost invariably caused by carelessness or negligence. Table 1 indicates that the fiscal year ending June 30, 1931, ras by no means a satisfactory one as regaris either the number of explosions or the number of persons killed by them. This tabulation lists all ignitions to which the attention of the personnel of the safety division was called and in- cludes not only major disasters, but also explosions in which fewer than five were killed, as well as several explosions from which no fatalities resulted. It will be noticed that last year there were 26 explosions in mines in 10 States of the United States, resulting in 217 deaths. In the previous year there were 34 explosions with a death list of 199, and in the year before there were 38 explosions with a death list of 139. Hence, the past fiscal year had distinctly a poorer record of fatalities from mine explosions than either of the two previous years. Of the 26 explosions in the past fiscal year, Pennsylvania had 7, West Virginic 4, New Mexico and Ohio 3 each, Alabama, Oklahoma and Washington 2 each, and California, Illinois and Indiana 1 each; the one in California was in a tunnel being driven for water purposes but giving off explosive gas (methane). In fatalities Ohio had the worst record with 38, Oklahoma came next with 45, then Indiane with 38, and Pennsylvania with 23; although Alabama had 2 ignitions and Washington 1, they caused no fatalities. Utch, Colorado, and Kentucky had no explosions reported by the safety division of the Bureau of Mines during the past fiscal year, but were on the list for the previous year, though in the case of Colorado there were no fatalities. On the other hand, Indiana and New Mexico, neither of rhich was charged with an explosion in the two previous years, were on the list for the past fiscal year; New Mexico had the bad record of three explosions, though fortunately with but a total of eight fatalities. Ohio reported 3 explosions to the safety division of the Bureau of Mines in the past fiscal year, 2 in the pre- vious year, and 3 in the year before that, or 8 in the past three fiscal years with 92 fatalities; all of these eight explosions were in open-light mines.

Dec 1, 1931

By Irving Hartmann

Falls of roof in coal mines and means of preventing them have been subjects of study for many years, and ran extensive literature has resulted, Usually each individual paper has placed 'emphasis on one phase of the subject, such as fatalities, nature and extent of nonfatal injuries, methods of tembering (particularly in rooms or other wide places), safety along retreating rib lines, and methods of causing falls in abandoned areas. It is only in recent years that there has been persistent question as to why

Jan 1, 1941

By Richard A. Dick

Eight blasts were fired in a 2-1/2-ft bench in the Stewartville member of the Galena Limestone formation in an aggregate quarry near Stewartville, Minn. The shots were dimensionally proportional to production-size bench blasts and were about 5 to 10 percent of full scale. The effects of site, timing of initiation, and burden-to-spacing ratio were studied in a 2 x 2 x 2 factorial experiment, using three boreholes, caw;, containing a 1/2-in charge diameter of high-density ammonia dynamite, in each blast. Detonation velocity measurements indicated that the dynamite detonated satisfactorily in the 1/2-in charge diameter. The effects of the three experimental variables were analyzed by weight for the percentage of oversized material produced and for size distributions determined by screening the entire muckpiles. The bench faces were painted before each shot in an effort to determine the origin of the oversized material. The square pattern (burden and spacing = 15 in) produced finer overall fragmentation and less oversized material than the rectangular pattern (burden = 15 in; spacing = 22-1/2 in). Sites 1 and 2 were about ft apart. Although site 2 produced slightly better overall fragmentation than site 1, the amounts of oversized material produced showed no significant difference. The timing of initiation (instantaneous or delayed) did not significantly influence the overall fragmentation or the amount of oversized material produced.

Jan 1, 1973

By Claude W. Sill

In the usual volumetric determination of uranium, the solution containing uranium is reduced in a Jones reductor, yielding a mixture of trivalent and tetravalent uranium; the trivalent uranium is oxidized to the tetravalent state by bubbling a stream of air through the solution. The resulting solution of. Tetravalent uranium is titrated with a standard oxidant, generally sulfatoceric acid, dichromate, or permanganate; It seemed likely that the, same general procedure could be used in determining semimicro quantities of uranium if the conditions affecting the variables involved were understood more clearly than at present. In the method described below, the use of ferric sulfate to oxidize tetravalent uranium allows the titration to be made at room temperature in an essentially colorless solution with sulfatoceric acid. The latter oxidant its turn permits the use of the very stable indicator, ferroin, with its sharp color.., change and exactly reproducible blanks. Solutions of uranyl sulfate were prepared by diluting a stock solution that had been standardized gravimetrically according to the method of Lundell and Knowles (8).3/ Solutions of sulfatoceric acid were prepared according to the directions of G. F. Smith (12) and were standardized against arsenic trioxide in the presence of osmic acid according to the directions of Gleu. The cerium solutions were stored in 18-liter carboys fitted with siphon arrangements so that the bottles did not need to be opened and protected from light in a dark cupboard. Under these conditions, even the 0.01 N solution changed by less than 1 part per thousand over a period of about 6 months.

Jan 1, 1952

By Michael V. Markel

This report summarizes work performed under USBM Contract No. J0100047 revealing the performance characteristics of a composite-type resilient screen deck. The ability of the composite to perform or compete with steel in noise attenuation and longevity was of interest. Tests were conducted at the River King Preparation Plant of Peabody Coal Company. This facility was chosen because it provided parallel process flow and met standard coal cleaning requirements. Comparisons could be made between the adjacent resilient and steel screen decks under similar operating conditions. Noise reductions of 1-6 dBA were realized in the near field. Although the test period did not determine resilient screen life, indications are favorable for their longevity.

Jan 1, 1981

By D. W. Butner

This Information Circular , one of a series published by the Bureau of Mines , reports on the methods and costs of mining and concentrating zinclead ore at the Highland Surprise mine in the Pine Creek area of the Coeur d'Alene region of Idaho . The mine is owned and operated by the Highland Surprise Consolidated Mining Co. , which supervises operations of the Nevada Stewart group of claims , which is adjacent on the northwest . These properties are at the extreme eastern end of a zone of fracturing that strikes northwest across the Pine Creek area . In fractures along this zone are the principal Pine Creek mines ; these are the Highland Surprise , Nevada Stewart , Sidney , Denver , V and Idaho , Liberal King , and Northern Light . Country rock at the Highland Surprise is argillite of the Prichard formation (Belt series ) . Fracturing has permitted the movement of mineral- izing agents that have replaced adjacent walls and crushed country rock with sulfides . Ore minerals are sphalerite and galena with accessory pyrite , chalcopyrite , pyrrhotite , and siderite . Three principal ore shoots were found on the Highland Surprise property . The Highland ore shoot was mined from outcrop to the 400 level . The Surprise ore body has been developed to a depth of 1,400 feet on the dip of the vein . The outcrop of the Surprise ore shoot was 150 feet long and 2 to 4 feet thick ; on the 1,150 ( lowest ) level , the ore shoot is 320 feet long and 10 to 17 feet thick , with good zinc content . Surprise ore shoot No. 2 occurs 250 feet west of No. 1 and has been mined from the 500 to the 1,000 level . From 353,000 tons of ore mined between 1910 and 1948 , the property has a recorded production of 256,000 ounces of silver , 7,500 tons of lead , 24,000 tons of zinc , and 412 tons of copper . Both shrinkage and cut and fill stoping methods are used at the Highland Surprise , but shrinkage is unsuitable for mining below the 700 level , because faulting has weakened the walls . Development of the Surprise ore , as well as exploration laterally and along the strike , is prosecuted steadily . A prospect heading is being pushed westward toward Nevada Stewart ground from the 700 level . The mill has a rated capacity of 275 tons per day and operates near capacity . Selective flotation makes zinc concentrate that is shipped to the Anaconda smelter and lead concentrate that is trucked to the Bunker Hill smelter at Kellogg .

Mar 1, 1950

By V. B. Royer, C. H. Harty

"MANGANESE-SILOCON ALLOYS AS DEOXIDIZERSThe basic open-hearth process for steel mining requires large amounts of oxidized iron for oxidation of the elements carbon, silicon, manganese, and phosphorus which are to be removed from the metal. Some of this oxidized iron (FeO) dissolves in the metal during the refining process, Subsequent to the elimination of the elements named, a considerable amount of dissolved iron oxide must be removed before the metal may be cast into ingot form. The elements generally used, for iron oxide removal, or deoxidation, are silicon, manganese, and aluminum. Silicon and manganese are always alloyed with iron, either singly or in combinations of various compositions. Aluminum generally is used in a commercially pure state and sometimes in complex alloys. A double deoxidizer of manganese and silicon alloyed with iron for furnace deoxidation has been the subject of an extensive cooperative investigation between the United States Bureau of Mines, the Carnegie Institute of Technology, and the Metallurgical Advisory Board. Certain grader of steel, especially low-carbon rimming steels, require a low-carbon deoxidizer to keep the finished steel within the carbon specification after deoxidation. ACKNOWLEDGMENTThe authors wish to acknowledge the assistance of J. F. Sanderson and S. S. Johnston in the analysis of the alloys used in this work.PURPOSE OF WORKThe need for definite information as to which compositions of manganese and silicon within a certain manganese-silicon ratio and when alloyed with iron would have an allowable carbon content for the particular grade or type of steel on which the deoxidize is used, prompted the undertaking of this investigation to determine the solubility of carbon in manganese, silicon, and iron alloys within the region bounded by 10:1 and 4:l manganese to silicon ratios. These data should be of value to the manufacturer producing such"

May 1, 1934

By J. H. East, R. S. Sanford, W. M. Traver, W. S. Wright

"INTRODUCTION This report describes the results obtained from a diamond-drill exploration project performed by the Bureau of Mines on the nickel deposits of the Yakobi Island, Alaska. The Federal Geological Survey 6/ completed a detailed geologic study and mapped the area during the summer of 1940, and a Bureau of Mines examining engineer 7/ made a preliminary examination of the deposits in June 1941, at which time core drilling was suggested as the logical means of determining the extent and grade of the deposits. Equipment and supplies were unloaded on the beach at Yakobi Island on October 21, 1941. The drills were moved to Bohemia Basin, where actual drilling operations wore begun under the direction of a Bureau of Mines engineer 8/ on November 7, 1941. Two core-drill holes were completed on December 7, 1941. Upon the request of the drilling contractor, operations were recessed owing to severe winter conditions. Work on the project was resumed April 27, 1942, under the direction of another Bureau of Mines engineer 9/ and was completed August 15, 1942. During the 1942 season, 13 core-drill holes were completed, and 10 surface pits and a tunnel were sampled. A total of 5, 191 feet of core-drill hole was drilled in 15 holes during the entire project. The results of drilling and sampling form the basis of this report."

Jan 1, 1948

By S. P. Kinney, P. H. Royster, T. L. Joseph

"The study described in this paper, on the reactions in an iron blast furnace, is part of the investigation being conducted by the Bureau of Mines on combustion of coke and the reduction of iron oxides in the blast furnace. Previous study of the combustion zone of the iron blast furnace, by means of a series of as samples taken through the tuyeres across the hearths of 13 blast furnaces, showed that the combustion of the coke in the blast-furnace hearth is complete at a distance of 32 to 40 inches from the nose of the tuyere, measured horizontally toward the center of the furnace. The results of this previous work are sum¬marized in the curves shown in figure 1, where it will be noted that practically all of the oxygen disappears at a distance of approximately 30 inches from the nose of the tuyere.In order to determine the height at which oxygen is found in a vertical direction above the tuyeres - it had been suggested that the combustion zone turned upward near the tuyere and to obtain comparisons with the samples taken at the Bureau of Mines experimental6 (5-ton) blast-furnace at Minneapolis, the Bureau extended the gas sampling on a commercial furnace to a number of planes between the tuyere level and the stock line. The sampling was conducted on a 300-ton furnace, making foundry iron, operated by the Central Iron and Coal Co., at Holt, Ala. The furnace was smelting Southern red and brown ores and nodules from pyrite sinter. Figure 3 is a vertical section of the furnace showing the six planes sampled."

Apr 1, 1926

By J. M. Kurtz

Ten Methane Monitoring Systems and Machine Control Circuits were examined and tested per the requirements in CFR Title 30, Parts 18 and 27, the Standard UL 913 and the document "Test Requirements For Instruments or Apparatus to be Considered for M.E.S.A. Intrinsically Safe Certification (Tentative)". The test results indicate that none of the products complied with all parts of all requirements as interpreted by Underwriters Laboratories Inc.

Jan 1, 1980

By J. H. Field

Synthesis of hydrocarbons by the Fischer-Tropsch reaction in a hot-gas- recycle system was demonstrated to be technically feasible. This project was undertaken, by the Bureau of Mines, to determine if the system was operable and to ascertain the optimum conditions for the production of gasoline. Carbon steel turnings packed with a void volume from 88 to 90 pct. were satisfactory catalysts, but steel catalysts with greater void volume, either turnings or steel wool, were not as active. Good temperature control with a pressure drop of less than 0.5 pounds per square inch (p.s,i,) per foot of catalyst bed of turnings was obtained by operating with a recycle to fresh feed ratio of 20 and by splitting the total gas flaw and injecting portions into the reactor at different entry ports.

Jan 1, 1961

By James H. Gary

Data regarding the composition and physical properties of Florida land-pebble phosphate-waste slime are presented, and the feasibility of dewatering and beneficiating the slime by several different methods is discussed. Chemical analyses, electron micrographs, and X-ray diffraction data showed that principal constituents of the slime included quartz, attapulgite, and flaorapatite. Viscosity of the slime changed with pH; thixotropic, Newtonian, and rheopectic states were observed as the pH increased. Use of various flocculating agents was not effective in improving thickening properties of the slime. Dewatering tests using pressure filtration showed that temperature influenced the filtration rate more than pressure; the filtration rate at 165° C was tenfold that at room temperature. Selective flotation of the slime, using two different processes, gave promising results. About 25 pct of the phosphate was recovered in a concentrate assaying 31 pct P205, Other tests demonstrated that the slime could be successfully fractionated at 20-microns using a hydrocyclone. In hydrometallurgical tests about 80 pct of the phosphorus and alumina were chemically extracted from the slime using sulfuric acid. Limited bacteriological studies made of the slime showed that several types of microorganisms were present and grew in the material despite the presence of fluorine-bearing minerals.

Jan 1, 1963

By R. S. Dean

"Applied Mineral Physics, by R. S. Dean.- This is an introduction to the seven papers that follow. It discusses the practical aspects of mineral physics and outlines the theo¬retical viewpoint underlying the investigations reported herein.Explosive Shattering as a Possible Economical Method of Ore Presentation By John Gross and C. E. Wood. - It is shown that explosion shattering by impact is favored by large charges and by low ratio of water to charge. For 400-gram charges of dolomite crushed through 48 mesh the steam costs are less than 5 cents per ton of dolomite obtained. This is within the range of present steam costs for ball-milling dolomite.Electrical Properties of Minersl Aggergates I. Natural and Artificial Aggregates Crystallized Lead Sulphide By R.S. Dean and John Koster - This paper deals with the electrical properties of natural and synthetic galena. It is shown that massive crystalline galena has a normal positive temperature coefficient of resistance, whereas fine-grained steel galena has a negative temperature coefficient, the curve R v. T being exponential in form. That steel galena behaves somewhat like a leaky condenser is indicated by ballistic and alternating-current bridge measurements. In determining the cause of the erratic results of alternating-current resistance measurements it was observed that the measured re¬sistance was a function of the current through the specimen. The direct-current resistance was found to be proportional to the square of a superimposed radio-frequency current and independent of the frequency.The influence of grain size or the amount of metallic interface on the voltage-current characteristics at various temperatures on synthetic galena pastilles was studied. It is proved that the volts v. amperes curves are linear for all sizes and temperatures, that they have an intercept which is apparently a linear function of the temperature, and that their slopes are exponential functions of the temperature and give rise to a negative temperature coefficient of resistance.Apparatus for determing the Magnetic Constants of Mineral Powders by V,H, Gottschalk,and C. W. Davis.- A modified isthmus permeameter having a spark-suppressed primary and a multiplier in the secondary circuit to regulate the effect of capsules functioning as a twin isthmus is used to obtain quantitative data and normal induction and hystersis curves from small amounts of powdered material at fields surpassing 3.000 oersteds. Data and curves are given to demonstrate the calibration of the apparatus and the reproducibility of its results. Applications and limitations of the apparatus are noted.Magnetization Curves for Magnetite Poeders by V. H. Gottschalk and F. S. Wartman.- This paper gives measurements on four lots of purified and analyzed magnetites in mixed fractions with especial reference to the variation of permeability with grain size and with dilution by an inert material."

Feb 1, 1935

By Kenneth L. Bickel

During an underground mine fire, the importance of controlling the spread of smoke and toxic gases with suitable ventilation structures has been proven. However, under certain conditions, control of the propagation of the fire itself may be even more critical in insuring a safe mine evacuation. Fire doors offer the means for accomplishing both objectives. In 1978, the Bureau of Mines initiated research to evaluate the state of fire-door technology and develop and test a fire door suitable for large openings (10 by 12 ft or larger) in noncoal underground mines. This report discusses current fire-door technology in the context of the underground mine environment and the design, fabrication, lab testing, and in-mine field testing of a mineworthy fire door. This door has a 1.5-h fire resistance rating and limits temperature rise across the door to 2500 F during the first 30 min of fire exposure.

Jan 1, 1987

By D. L. Paulson

Electric furnace smelting of blister copper directly from copper precipitates (cement copper) was investigated by the Federal Bureau of Mines. Copper concentrations in five different lots of cement copper in the investigation ranged from 62.5 to 82.5 wt-pct. Laboratory-scale smelting tests were made in a 50-kva electric-arc furnace to establish the reductant and flux requirements. Best recoveries were realized by adding 60 pct of the carbon required to combine with the contained oxygen in the cement copper. Operating parameters established during the laboratory-scale smelting tests were used successfully in smelting 20 tons of cement copper during 12 pilot-scale tests in an 800-kva electric-arc furnace. Over 98 pct of the contained copper was recovered as blister-grade metal. The projected energy consumption for a commercial-size furnace was 380 kwhr per ton of cold charge.

Jan 1, 1978

By F. G. Schwartz

This circular presents the results of a survey of research on jet fuel thermal stability jointly sponsored by the National Petroleum Refiners Association (NPRA), Tulsa, Okla., and the Bureau of Mines. The development of supersonic planes has led to many problems that did not exist in the operation of subsonic aircraft. One of the most important of these is rapid deterioration of the fuel at the high temperatures to which it is subjected. At higher speeds, aerodynamic heating of the airframe imposes severe thermal problems, and conventional techniques of rejecting the heat to the atmosphere become impractical. The fuel is the only material present in sufficient bulk to be used as a heat sink. Thus, the fuel is subjected to aerodynamic heating and also is used to dissipate heat from lubricating oil, hydraulic fluid, electronic equipment, wheel wells, and cabin air. Consequently, the fuels may have to withstand both moderate temperatures for sustained periods in the fuel tanks and higher temperatures for brief periods during transfer from the tanks to the combustion chamber. Because of high temperatures, insoluble residue or gum may form in the fuel and contribute to heat exchanger fouling and to clogging of the fuel manifolds, nozzles, control systems, and other components of the fuel system.

Jan 1, 1962

By Paul M. Ambrose

ADVANCES in mining and processing technology made it possible to reopen the De Beers diamond mine in South Africa, originally located in 1871 by Cecil Rhodes and closed in 1908. Radioactive material was used to indicate the efficiency of hydro-cyclones used in diamond concentration. Added interest was shown in recovering diamond from the sea off the coast of South-West Africa. Production of crude artificial abrasives declined because demand was paritally met by withdrawals from stocks. The value of graded grain-coated abrasives and grinding wheels surpassed those of 1962.

Jan 1, 1964

By A. J. Kraemer

The properties of crude petroleum continue to interest the Bureau of Mines and constitute an important phase of its major studies on the mineral resources of the United States. The Bureau's interest in the subject has been intensified by frequent requests for information on the characteristics of crude petroleum from various producing fields. Since its inception the Bureau of Mines has collected and analyzed samples of typical oils and at present has surveyed and classified crude petroleums from nearly all the known oil fields of the Western Hemisphere. Results of these surveys have been presented in various Bureau of Mines publications. (See bibliography, appendix A, p. 145.) The nature and comparative value of crude oils from various countries and the extent to which these oils may be considered potential competitors for markets are of manifest importance to the petroleum industry in all lands, largely because all crude oils, wherever produced, are either actual or potential competitors for a market with all other crude oils. The numerous discussions of foreign production of oil that have appeared in the technical press in the past indicate the great interest of the United States in this subject.

Jan 1, 1937

By Jack R. Woodyard

Scientists at the U.S. Bureau of Mines are studying iron aluminides as possible substitutes for stainless steels to reduce the Nation's dependence on imported strategic and critical materials. In a Bureau investigation on the mechanical properties of Fe-28Al, it was found that the material's machining properties were significantly improved at slow tool and feed speeds. Machining techniques normally used for brittle materials failed or were costly. Further experiments using a 5-in (12.7-cm) mill cutter with carbide inserts, operating dry at minimum machining speeds, produced visually smooth sample surfaces with no tool damage. As a result of these experiments and a review of published data on hydrogen embrittlement of iron aluminide under tension, non-water-based (e.g., sulfur-based) lubricants were chosen for production machining. Four-flute, 3/4-in (19-mm) carbide end mills were used at slow speed under lubrication. This latter procedure reduced tool wear and breakage by a factor of 2. Machined surfaces and specimen cross sections were analyzed by scanning electron microscopy to detect microcracking. Tensile tests gave the expected yield and ultimate strengths, indicating that no degradation by low-speed machining occurred. This study extends this work to show that the alloy can be machined at higher speeds using high-speed steel end mills, and that water-soluble cutting oil is a suitable lubricant and coolant.

Jan 1, 2010

By A. H. Shoemaker

This paper describing the mining practices at the Old Dominion mine, Globe, Ariz., is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various minim districts in the United States. The Old Dominion mine is situated in the eastern port of the Globe-Miami district, about 1-1/2 miles north from the center of the town of Globe. An average of nearly: 1,200 tons per day was mined during 1928. The prevent production is about 1,500 tons per day; of this amount,, approximately 100 tons is direct-smelting ore that is shipped to the smelter at Miami and 1,400 tons milling ore which is treated in the company?s concentrator at Globe. About 600 men are employed at the mine.

Jan 1, 1930