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By B. H. Eccleston, R. F. Kendall, D. E. Hirsch, Norman G. Foster

The mass spectra of 23 alkylthiophenes are presented , including 21 that have not been previously reported . Correlations between mass spectra and the structure of the thiophene homologs are discussed . Comparisons with , and corroboration of , earlier workers ' correlations and predictions are made . Several additional correlations are reported to enable the spectroscopist to identify the substituents on alkyl - substituted thiophenes , and the relationship of the mono - substituted and 2,5 - disubstituted alkylthiophenes is discussed in detail .

Jan 1, 1964

By R. Karl Zipf

The sudden, violent collapse of large areas of room-and-pillar mines poses a special hazard for miners and mine operators. This type of failure, termed a 'cascading pillar failure' (CPF), occurs when one pillar in a mine layout fails, transferring its load to neighbouring pillars, which causes them to fail, and so forth. Recent examples of this kind of failure in coal, metal and nonmetal mines in the U.S.A. are documented. Mining engineers can limit the danger presented by these failures through improved mine design practices. Whether failure occurs in a slow, non-violent manner or in a rapid, violent manner is governed by the local mine stiffness stability criterion. This stability criterion is used as the basis for three design approaches to control cascading pillar failure in room-and-pillar mines-the containment approach, the prevention approach and the full extraction mining approach. These design approaches are illustrated with practical examples for coal mining at shallow depth. Cascading pillar failure {CPF) in room-and-pillar mines can go by many other names, such as `progressive pillar failure', `massive pillar collapse', 'domino-type failure' or 'pillar run'. In this kind of failure when one pillar collapses the load that it carried transfers rapidly to its neighbours, causing them to fail, and so forth. This failure mechanism can lead to the rapid collapse of very large mine areas. In mild cases only a few tens of pillars might fail; in extreme cases, however, hundreds, even thousands, of pillars can fail. CPF can have catastrophic effects on a mine, and sometimes these effects pose a greater risk to health and safety than the underlying ground-control problem. Usually, the CPF induces a devastating air blast as a consequence of the displacement of air from the collapse area. An air blast can disrupt the ventilation system totally by destroying ventilation stoppings, seals and fan housings. Flying debris can seriously injure or kill mining personnel. The CPF might also fracture a large volume of rock in the pillars and immediate roof and floor. In coal mines and certain other mines this can lead to the sudden release of large quantities of methane gas into the mine atmosphere; a methane explosion might result from the CPF. CPF is at the far end of the spectrum of unstable pillar failure. At the other end are slow `squeezes' that develop over days to weeks and, because of their slow progress, do not pose an immediate danger to mining personnel. There is ample warning time for men and machinery to get out of the way of the failure. In a CPF, however, the failure progresses so rapidly that men and equipment cannot be evacuated in time. Significant seismic energy is released as a consequence of the rapid failure and collapse. CPF should not be confused, however, with coal-mine bumps and rockbursts. In some cases the damage can appear similar, but the underlying mechanics are completely different. As will he shown later, the mechanics of CPF depend on the applied vertical stress and the post-failure, i.e. strain-softening, behaviour of the pillars. In a CPF pillars shed their applied load rapidly and have very little residual strength after failure. The collapse itself may release significant seismic energy, but otherwise the mine is seismically quiet. Alter a CPF the openings in the affected mine workings have usually closed completely. In contrast, coal-mine bumps and rockbursts occur in seismically active mines. Research has shown that coal-mine bumps and rockbursts are seismic events induced by mining that damage underground mine workings. Bumps and bursts are thus a subset of a much larger set of mining-induced seismic events.[ Only some of these seismic events damage mine workings; fortunately, most do not. The mechanisms by which a mining-induced seismic event can lead to a damaging coal-mine bump or rockburst is still a significant research area.2 After a bump or rockhursr the affected mine workings may or may not be completely closed. For example, in the coal-mine bump described by Soler and co-workers2 the mine workings remained open even though the pillars were destroyed during the bump event. Because CPF differs from a coal-mine bump or rockburst, the design approaches to control their occurrence also differ. The design recommendations developed here apply to CPF and not to bump- or burst-prone mines. Cascading pillar failure examples Unfortunately, CPF has occurred in room-and-pillar coal, metal and non-metal mines. The most infamous example is the Coalbrooke colliery in South Africa, where 437 miners perished where [si >1 3at1ttsumsus7car kky vArtMixiL7i nesafr tramwsamn ures] on 21 January, 1960.1 Table I summarizes the mining dimensions of 13 examples of rapid pillar collapse in U.S. coal mines. All occurred during the 1980s and 1990s, and all happened suddenly or without significant warning. Most resulted in air blasts and damage to the ventilation system. Table 2 gives the mining dimensions of six room-and-pillar metal and non-metal mines in the U.S.A. where failure occurred in all probability by the CPF mechanism. The collapse areas can be huge. Fortunately, some of these failures gave advance warning. At the lead-zinc mine slabbing from pillars and roof falls began four weeks prior to the main collapse.3 At the copper mine considerable rock noise and smaller failures preceded the main collapse by five days.5 At the copper-silver mine it is not known if nature provided a warning.6 Evidently, the trona mine collapsed without warning.7,8 Rock noise and other failure warnings preceded the silica mine collapse by three weeks. v The presence or absence of warnings at the salt mint is not known. to Most of these collapses induced a substantial air blast; damage to the ventilation systems was limited, however, to bent airdoors and a few downed stoppings, except at the trona mine where extensive damage to the ventilation system resulted.

By Daniel G. DiCanio

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

Jan 1, 1976

By C. A. Taylor, C. E. Munroe

"In blasting the explosion of the high explosives charge is initiated by means of a detonator. Consequently the successful operation of the whole system is, ab initio dependent upon the suitability and efficiency of the detonator used. A considerable number of methods for testing the efficiency of detonators have been devised. In a previous publication*** of the Bureau of Mines many of these were discussed after having been classified as direct and indirect methods.In 1910, W. O, Snelling, then explosives chemist of the Bureau, devised a direct method which depends on the extent to which a hard brittle material of uniform granulation, such as quartz sand, is pulverized by the explosion of the detonator when imbedded in it, and, as a container in which to carry out the tests, he devised the vessel known as the Bureau of Mines sand-test bomb No. 1. A brief mention of his work was made in a paper presented to the Engineers' Society of Western Pennsylvania.****Later Storm and Cope made a very extended investigation of this method using sand-test bomb No, 1. Their paper***** contains a detailed, illustrated, description of sand-test bomb No. 1, with precise specifications of the sand and a minute account of the technique followed, together with a discussion of the data they obtained from the tests in this bomb of 112 detonators representing each of the grades from We, 3 to No. 10, inclusive. The average of results obtained by them are set forth in the following table."

Dec 1, 1923

By John H. Hild

"INTRODUCTION Alunite occurs within a radius of 10 miles of Marysvale, Piute County, Utah, in veins and as replacements of igneous rocks. A number of each type of deposit was explored by the Bureau of Mines, in cooperation with the Geological Survey, under the Strategic Minerals program during 1942. The exploratory work comprised geologic and topographic mapping, diamond drilling,,bulldozer and hand trenching, sinking test pits, rehabilitation of old workings, sampling alunite exposures, and constructing and repairing roads.ACKNOWLEDGNENTSIn 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 preliminary 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.With particular reference to this publication, acknowledgment is given to Richard E. Mieritz and William E. Young, who assisted on the project at various times; P. T. Allsman, chief. Salt Lake Division, Mining Branch, who advised on exploratory problems and gave valuable assistance in preparing the report and illustrations; A. P. T. Schumann, for preparing the illustrations; and to Gordon L. Bell, Max Willard, and Eugene Callaghan, of the Geological Survey, who cooperated as representatives of that agency."

Nov 1, 1946

By Jingcheng Li

Currently many underground coal mines worldwide have installed or been planning to install a tracking system to trace miners mainly for their safety. Although many systems have been reported functional, a lack of sophisticated and systematic error correction methods apparently is still an issue for them; often it results in a low system resolution. To improve the system resolutions, this paper introduces two position adjustment methods for mine tracking systems. The first is an entry-matching method that optimally adjusts an off-course tracking device to the closest tunnel (entry). The second is a distance measurement adjustment method that accurately adjusts the position of a tracking device along an entry according to a measured distance from the device to a reference point. The coplanar node-path network mine model is used as the foundation for the development of these two methods.

Jan 1, 2009

By Joel N. Van Sant

An investigation was conducted to study possible sources of Utah refractory and structural clays that could be used for the manufacture of refractories and light or buff burning heavy-clay products. A field study was made and the clay samples tested to determine their firing characteristics. Results of the Bureau's work indicate many small noncommercial deposits of hypogenic clay occur in igneous rocks. Commercial hypogenic deposits are mostly halloysite clay developed by hydrothermal replacement of limestone. The high firing shrinkage of halloysite precludes its use as a refractory, however, halloysite produced at the Dragon Mine south of Eureka, is used fur making oil catalysts. Clays and shales suitable for low heat duty refractory products are found in the Manning Canyon shale, in shales associated with coal bearing rocks, and in the Dakota formation. Some of the clays from the Dakota formation are also suitable for high-duty refractory products.

Jan 1, 1964

By W. L. Cooley

Electrical accidents occurring in coal mines from 1975 through 1979 were categorized and analyzed. The data was searched for common electrical hazards, common activities on the part of those injured, and common negligent or careless behavior. The most common electrical hazard was abnormal arcs or sparks, the most common injured activity was handling energized trailing cables, and the most common careless behavior was failure to de-energize circuits before working on them. The accident data was combined with mine production statistics to form a normalized electrical accident rate. It was found that some mines have consistently more lost workdays per man-hour worked than do other mines. Bureau of Mines electrical safety research contract expenditures were reviewed to judge whether the research effort was directed to those areas which are related to the most accidents. In some cases it was not. A method was devised and utilized to estimate the relative cost to the mining industry to implement certain safety measures developed through Bureau research, and also to estimate the potential safety benefits. Some safety changes are recommended, others are not. MSHA regulations were reviewed for effectiveness in preventing electrical accidents, and suggestions were made for discontinuing, clarifying, or otherwise modifying the regulations.

Jan 1, 1981

"A bed, British Columbia, Canada, coal, carbonizingproperties B 510Pa., coal, washing characteristics RI 4941A' bed, Pa., coal, washing characteristics RI 4834"

Jan 1, 1960

By G. W. Birge, D. E. Wolfson, J. G. Walters

Seventeen samples were carbonized by the BM -AGA pilot - plant test method and in industrial ovens . Chemical and physical properties of the samples were determined , and the physical properties of the cokes prepared by the two methods were compared . Since the capacity of the plants from which these samples were obtained is about 30 percent of the 1959 total for the United States , the data given in this report are indicative of the chemical and physical properties of blends used to produce industrial cokes and the acceptable chemical and physical properties of the resultant coke .

Jan 1, 1964

By John R. Troxell

"INTRODUCTION The Ahles iron mine, also known as the Pequest mine, in Warren County, N. J., was operated continuously for 15 years and was still in ore when it closed in 1916.Tie property was examined by an engineer of the Bureau of Mines in March 1943. 3/ This examination led to an investigation of the deposits by the Bureau by diamond drilling two holes under the old workings to determine whether the extends downward.This report describes the work done at the Ahles mine by the Bureau and presents the data obtained.ACKNOWLEDGMENTSIn its program of investigation 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. The Mining Division, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual investigative work, and prepares the final report.The Metallurgical Division, O. C. Ralston, chief, analyzes samples and performs beneficiation tests.The investigation was under the general supervision of J. B. Zadra, acting regional engineer, and under the immediate supervision of G. D. Jermain, district engineer for the States of Pennsylvania, New Jersey, Maryland, and Delaware. The author was in direct charge of the project.The chemical analyses for the project were performed at the College, Park, Md., laboratories of the Bureau of Mines under the direction of M. S. Sheftel. The ore-dressing tests were conducted at College Park under the direction of Frank Lamb. Preston E. Hotz, of the Federal Geological Survey, logged and interpreted the drill cores."

Apr 1, 1948

By M. H. Kline

The Scarlet mine, in Randolph County, N. C., was operated on a small scale at intervals from 1899 to 1915, but no records of the quantity of ore produced are available. J. I. Moore unwatered the mine in March 1948, and Bureau of Mines' engineers examined the underground workings. Several assays checked previous sampling of the mine and indicated a small but comparatively high-grade copper-zinc deposit. The high metal content of the veins and the possibility of developing additional reserves prompted the Bureau of-Mines to drill three holes, totaling 530 feet, at the deposit during March and April 1948. Drilling disclosed that the mineralized vein did not extend over 300 feet along the strike and is probably limited in depth to the contact with the granite mylonite.

Jan 1, 1949

By D. B. Gawthrop

"In connection with the proposed use of Cordeau-Bickford to fire L.O.X. (liquid oxygen explosives) in well drill holes, the question has arisen as to the effect of very low temperatures on (1) the rate of detonation of Cordeau-Bickford; (2) the sensitiveness to detonation of its TNT filling; and (3) the lead covering of Cordeau-Bickford.The Cordeau-Bickford used in this investigation was the standard 6 mm. size, such as is regularly used in blasting, and was manufactured and furnished by the Ensign-Bickford Company, Simsbury, Conn. All pieces tested were taken from rolls, all of which were from the same melted batch of TNT in order that all the pieces tested might be as nearly identical as possible.Different portions of this Cordeau-Bickford were tested plain (not countered), countered, and double countered. The countering and double countering was carried out by the manufacturer prior to shipment.The determination of the temperature at the instant of making a test was accomplished by the use of a Leeds and Northrup potentiometer and copper constantan thermocouples. Each couple was made from No. 28 B & S gage wire with short junctions. One junction was inserted in a hole drilled by a No. 60 drill through one lead wall of the Cordeau-Bickford to approximately the opposite wall, so that this junction was in the center of the TNT filling while the other junction was immersed in ice water. The potentiometer readings in millivolts were converted to °C. from the calibration curve of the thermocouple wire,"

Jun 1, 1924

By R. C. Hickman

"INTRODUCTION The largest known deposits of ilmenite and rutile in Virginia are in Amherst and Nelson Counties. Other deposits occur in the State, but their extent is not known. One of the most promising of the latter is the deposit in Roanoke County on the T. M. Bush and the H. L. Hutchins property near Roanoke. A geophysical survey was made of the deposit, followed by core drilling. In April and May 1946, four holes were drilled, totaling 822 linear feet.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 preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, Oliver C. Ralston, chief, analyzes samples and performs beneficiation tests.The project was under the immediate supervision of Mitchell H. Kline, chief, Raleigh Division, Mining Branch,. Bureau of Mines."

Aug 1, 1947

By Stephen D. Cramer

The Bureau of Mines conducted a study in which the magnetic fraction of urban refuse was used as melting stock in the preparation of high-strength, low-alloy and carbon steel. Product steels, made from incinerated steel can scrap, nonincinerated-nondetinned steel can scrap, nonincinerated-detinned steel can scrap, and dilutions of these scraps with No. 1 heavy melting scrap, were used in continuing tests in industrial, rural, and marine environments to determine the effect of residual elements and atmospheric pollutants on their atmospheric corrosion resistance. The respective commercial steels were exposed at the same time to establish baseline corrosion data for the test sites. Weight-loss data are reported for atmospheric exposures of 0.5, 1.0, 1.5, and 3.8 years. The marine environment was the most corrosive; the industrial environment was the least corrosive. The atmospheric corrosion resistance of the carbon steel was improved 25 pct by using incinerated scrap and nonin-cinerated-nondetinned scrap in the steelmaking process. In no case was the atmospheric corrosion resistance of carbon steel degraded by using the magnetic fraction of urban refuse as melting stock. The presence of sulfur in the corrosion film was the most important factor affecting the corrosion resistance of the steels. With increasing sulfur concentration, the rate of the corrosion reaction was reduced and the corrosion film became more protective. The residual elements in the product steels most responsible for improving corrosion resistance were copper and tin. These elements tended to increase the concentration of sulfur in the corrosion film. At the levels present in the product steels, Cr, Ni, and Pb had no observable effect on the corrosion resistance of the steels.

Jan 1, 1980

By W. M. Myers

Water has been commonly used as a collecting medium in many instruments employed in the sampling of dusty atmospheres in mines** add industrial plants, and for this purpose has much to recommend it, particularly the following factors:1.,Water is a very efficient dust collector.2.,Distilled water of great purity may be readily obtained at slight expense. The analytical error introduced by the extremely small amount of foreign matter in carefully distilled water is very small,3.,Water is a very convenient medium with which to work as all the analytical operations of diluting, aliquoting, and filtering are readily and speedily carried out. Water has therefore been used extensively in such instruments as the Palmer apparatus, the Greenburg-Smith impinger, and the dust collector recently described by Drinker, Thompson, and Fitchet. The Bureau of Mines has conducted investigations in many metal-mining districts of the country, determining of dust the nature and amount of dust present in working places, its effect the health of workers, and what precautions may be taken to decrease the hazard of exposure to dangerous dusts. The Bureau is therefore interested in any factor that affects the accuracy of dust sampling.

Nov 1, 1923

By V. E. Edlund

This report presents the results obtained in a study of the technical feasibility of recovering a usable pig iron by pyrometallurgical treatment of typical copper reverberatory slags . The iron in the slag was readily reduced with carbon , but the copper and sulfur content of the metal was best controlled by a three - stage procedure comprising ( 1 ) melting the slag with pyrite to remove copper as a low- grade matte , ( 2 ) smelting the partly decopperized slag with fluxes and carbon to reduce the iron , and ( 3 ) refining the impure iron alloy from step 2 with a flush slag to remove sulfur and residual copper . Laboratory - scale tests demonstrated that washing with 8 wt pct of pyrite lowered the copper content of a typical reverberatory slag from 0.58 to 0.12 Subsequent smelting of a mixture composed of 70 pct decopperized slag , 25 pct lime , and 5 pct coke reduced 84 pct of the iron to metal containing 2.27 pct sulfur . This metal then was successfully desulfurized by treatment with a basic flush slag to produce a finished metal that contained , in percent , 93.5 Fe , 0.02 S , 0.26 Cu , and 4.9 C. Overall recovery of iron under the conditions of trial was about 80 pct . This could be increased if higher tolerances for copper could be accepted . Commercial processing would be accomplished in three furnaces with molten materials passing from one to another . Currently produced smelter slag could be treated fairly inexpensively , because the molten product would require only a little additional heat to produce an iron byproduct that undoubtedly would be attractive to local foundries .

Jan 1, 1964

By R. E. Brewwe

"INTRODUCTION Anyone who has had frequent occasion to compare methods of analysis and testing as employed in European countries with those used in the United States has felt the need of a table or graph giving the relationship between the units of measurement of finely powdered materials. Most of the few published comparisons include only two series of sieves and often require tedious interpolations to adapt the data of one series to the series more familiar to the reader. To eliminate such deficiencies, the author hopes that the discussion and comparison of fine-series sieve sizes presented here will conserve the time of interested research workers.ACKNOWLEDGMENTSThe author is deeply indebted to Virginia B. Strathearn, scientific aide, for help in compiling the information from the literature and to W. A. Solvig, senior chemist, for valuable suggestions in preparing the manuscript.SQUARE-MESH-SIEVE SERIES OF DIFFERENT COUNTRIESSieving analyses of powdered materials have been placed on a comparable basis in different countries by the introduction and adoption of standard sieve-scale series. Series of wire-cloth square-mesh sieves in common I oratory and industrial use include: Institution of Mining and Metallurgy standard laboratory screens (I.M.M.); British Standards Institution standard for fine-mesh test sieves (B.S. or B.S.I.); Tyler standard sereer-scale sieves; United States standard sieve series; Deutsche Industrial-Nermen (DIN); and the standard control sieves of the Association Francaise de Normalisation (AFNOR). With the exception of the I.M.M. series in which the opening is equal to the diameter of the wire, the general proportions of the various series of sieves are similar. The size of British and American sieves is designated by the number of meshes or openings per linear inch or, more recently, by the number of microns per linear sieve opening. In a technical sense the word ""mesh"" is meaningless, unless the diameter of the wire is also given, so that the size of the opening can be determined. On the Continent sieves are designated either by the nunber of Mesh per linear centimeter or by the number of openings per square centimeter."

Jul 1, 1944

By H. R. O'Brien

"During the past year, the Pittsburgh experiment station of the Bureau of Mines has been investigating methods for the quantitative estimation of carbon monoxide in blood. This work was necessary because reliable methods of analysis are of the greatest importance in the bureau's research work on prevention and treatment of carbon monoxide poisoning among workers in mines and metallurgical plants. Two of the methods considered involve color comparisons. In one of these methods, differences in tint can be noted fairly readily, while in the other, they are much more difficult to detect. The latter, however, is otherwise considerably simpler. It was decided, therefore, in studying the possibilities of this second method, to use the most sensitive eyes in the laboratory force.Preliminary trials.The method under investigation was the Haldane carmine determination of carbon monoxide in blood. The plain oxyhamoglobin of the blood in dilute solution is a pale straw color, when exposed to carbon monoxide it becomes a cherry pink. In the analysis dilute indigo carmine is added to oxyhsmoglobin until the solution matches in tint the carbon monoxide hemoglobin. The eye wanted, then, was the one most sensitive to faint pinks. But just how to select the analyst was not clear At first the Williams test scale, used in the Navy, was considered, but on con¬sultation with Dr. L. L. Thurston, bead of the Department of Psychology at Carnegie Institute of Technology, the following procedure was adopted.Instead of standard tests made up of all colors, only those occurring in the analysis were used. Solutions were prepared of the two hemoglobins, from which twenty-four different pairs were made up and placed in test tubes like those expected to be used in the analysis. One of each pair differed from the other in percentage of carbon monoxide hemoglobin by amounts varying from 2-1/2 per cent to 20 per cent. Each pair was compared in a box built in our own shop. This was 20 inches long and 5 inches square in cross section. One end was covered with ground glass. Just inside this glass cover were provided two slots, each the width of the test tubes used. The tubes to be compared were dropped into these slots through two holes in the top of the box. The device was placed before a window away from the sun, and so arranged that the light conditions were the same on each slit or opening. The person to be tested was seated before the box, and as the two tubes were placed before him side by side, he marked whether A (left) or B (right) contained the more cherry pink. This procedure was continued till he had compared all the pairs."

Jul 1, 1921

By Jos. R. Guiteras

This paper is one of a series published by the Bureau of Mines on mining and milling methods and costs. It describes operations in the Alma district of Colorado in September 1937, supplemented by some additional data collected in July 1938. ACKNOWLEDGMENTS The author wishes to express his appreciation of the friendly cooperation extended him by the mine operators in the district. The greater part of the information was obtained from mine and mill superintendents to whom individual acknowledgment is made in the text.

Jan 1, 1940