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By Graham W. Marks

This report is the fourth of a series concerning the development of spectrochemical methods for the analysis of ore samples and related Metallurgical materials by the total-energy method. In this report, the application of this method to the determination of thallium is discussed. This element lies in group III of the periodic tale; one other Clement of this group; indium, has already been investigated.

Jan 1, 1949

By V. E. Erwin, W. W. Adams

"Production of explosives for industrial use in,the United States during 1934 continued the upward trend begun in 1933 from the low-level output of 1932, and the output in 1934 was only slightly less than in 1931.Reports to the United Stated Bureau of Mines from companies engaged in the manufacture of industrial explosives showed that the quantity of explosives manufactured in the United States and sold during 1934 for use within the various States was 314,767,922 pounds - 23 percent more than in 1931.Production during 1934 included 39,207,845 pounds of permissible explosives 5 206,625,027 pounds of high explosives other than permissibles, and,68,935,050 pounds of black blasting powder of which 37,192,700 pounds were in granular form and 31,742,350 pounds in pellet form. These figures represent an increase over 1933 of 15.6 percent for permissible explosives, 30.9 percent for other high explosive, and 7.4 percent for black powder.Coal-mining operations were the chief consumers of permissible explosives; 99 percent of the total output in 1934 was used, in coal mines. The proportion used by bituminous mines was 59 percent and by anthracite mines 40 percent. Coal mining was likewise the principal consumer of black blasting powder, taking 88 percent of the total sales during 1934; of this proportion, bituminous mines received 78 percent and anthracite mines between 9 and 10 percent. Consumers of high explosives other than permissibles were more varied; the reports showed that 11 percent of the total quantity sold was for coal mining, 22 percent for metal mining, 17 percent for quarrying and nonmetallic-mineral mining, 46 percent for railway and other construction work, and 4 percent for all other purposes."

Oct 1, 1935

By M. V. HANSEN, Frank PERZ, Edward Thomas, C. H. SEELING

This is the second of a series of information circulars dealing with the control of roof and the prevention of accidents from falls of rock and coal . Their purpose is to focus the attention of the coal-mining industry on the most - common source of fatalities and injuries in mining coal and to disseminate information that may be helpful in combating the roof - fall hazard . Inasmuch as approximately 85 percent of roof - fall accidents occur in the face region , the importance of analyzing the accident - producing aspects of methods of roof support at the face or lack of method overemphasized . - - cannot be This circular is not intended to be an exhaustive treatise on methods of roof support in face regions but rather is a description of several methods of support that appear to offer distinct advantages with respect to safety and efficient operation .

May 1, 1948

By D. G. Kesterkel

Low-melting thoriurnrbase binary alloys or metal solutions were prepared by two different techniques involving the electrolysis of ThO2 dissolved in fluoride melts. Experiments were performed at 950° to 1,250° C using electrolytes containing ThF4 and various alkali and alkaline earth fluorides. In the first method, electroreduction of ThO2 and deposition of thorium on a nickel or iron cathode formed a molten alloy that dripped off and collected on the bottom of the cell, or in a tungsten cup. An electrocodeposition technique was used to prepare thorium-base alloys or solutions containing nickel, iron, chromium, or manganese. Electrolytic reduction of the component metal oxides and simultaneous deposition of the two metals on a tungsten cathode yielded a liquid alloy product. Complementary experiments were performed on the fused fluoride electrowinning of dendritic thorium from Th02 at 1,075° to 1,200° C in which thorium crystals were recovered and arc-melted into buttons. Major contaminants were aluminum, carbon, copper, iron, oxygen, and silicon, totaling 0.2 percent.

Jan 1, 1966

By Michael A. Trevits

During the time period from 1990-2007, there were 1601 reportable fires that occurred in the U.S. mining industry (an average of 89 fires per year). The leading causes of U.S. mine fires include flame cutting and welding operations, frictional heating and ignitions, electrical shorts, mobile equipment malfunctions, and spontaneous combustion. The National Institute for Occupational Safety and Health (NIOSH) is conducting a program of research addressing metal/nonmetal and coal mine fire prevention, detection, management and suppression. In the metal/nonmetal area, work was focused on technology transfer and training, and research to reduce the number of mobile equipment fires and their hazards. In the coal arena, research is underway to determine the root cause of cutting and welding-related fires and to evaluate the effects of ventilation schemes relative to the spontaneous combustion risk in longwall mines. Relative to fire management, research is ongoing on remote mine seal installation and remote mine fire suppression technologies. Finally, research is continuing to develop comprehensive and usable smoke management techniques and to develop mine fire growth models, propagation, and suppression. This paper presents a summary of some of the mine fire research and provides an overview of the next phase of the NIOSH mine fire research program.

Jan 1, 2010

By Thomas M. Barczak

This Bureau of Mines report describes research on developing technology to utilize shields as roof load monitors. Three-dimensional equations of static quilibrium are presented for a generic two-legged long-wall shield. The equations are presented in the most general form, assuming a force and moment vector at each reaction by rigid-body analysis of the shield mechanics. The resulting system of equations was found to be indeterminate to a very high degree. A three-dimensional solution to measurement of the resultant reaction on the canopy by the strata activity and shield response required the elimination of several forces or moments that were thought to be nonparticipating or to not significantly affect overall shield mechanics. Required measurements for solution of the equilibrium equations were leg, canopy capsule, and lemniscate link forces. Two-dimensional analysis, which considered forces acting only in the roof-to-floor and face-to-waste plane, was also provided by reduction of the three-dimensional equations~

Jan 1, 1987

By R. E. Peterson

A reduction roasting/magnetic separation/flotation process for beneficiating oxidized taconite from the western Mesabi iron range in Minnesota was evaluated in a Bureau of Mines research program to insure an adequate supply of raw materials for future ironmaking and steelmaking needs. The research was performed on a sample containing 35.4 pct iron and representing a deposit of approximately 2 billion tons of raw materials. An average of 1,419 lb of oxidized taconite and 37 lb of lignite reluctant per hour were fed to a 35 -foot rotary kiln in which the iron oxides were converted to artificial magnetite. The kiln was heated with pulverized lignite and natural gas. Most of the dust collected from the kiln exhaust gas was pelletized and recycled to the kiln. Magnetic separation and cationic flotation of the roasted material in a 900-lb/hr pilot plant produced a concentrate analyzing 67.9 pct iron and 4.9 pct silica and containing 69.2 pct of the iron in the kiln feed.

Jan 1, 1981

By Kevin Connor

The Government's ban on all commercial mining operations, except for small-scale artisan exploitation of alluvial gold deposits, continued throughout 1985. Minerals produced were kaolin and lime for agricultural uses, and experimental peat harvesting for energy applications. The total value of the minerals produced during the year was estimated at $1.1 million .2 In early 1985, an agreement between the Government and Amoco International Oil Co. was ratified for a petroleum exploration concession covering 248,000 hectares of Lake Tanganyika. Onshore exploration in the Ruzizi Plain was already under way the last half of 1985. By yearend, enough seismic information was available that Amoco hoped to complete data analyses, determine onshore drilling sites, and begin drilling operations before the end of 1986. Also to begin in the latter part of 1986 were seismic studies of Lake Tanganyika. Throughout 1985, Amoco officials were negotiating with the Government of Zaire for expanding the exploration acreage into that country's portion of northern Lake Tanganyika and the Ruzizi Plain. An agreement between Amoco and Zaire could have important beneficial economic implications for both Zaire and Burundi, and onshore seismic work in Zaire logistically supported from Bujumburi could begin almost immediately.

Jan 1, 1987

By Albert J. Rambosek

The results obtained in a study of the stress conditions existing in a drill bit-point area and in the underlying rock, when the bit was in full but nonpenetrative contact with the rock, are presented. This investigation by the Bureau of Mines was the preliminary exploratory phase of a long-range program of research on rock drilling to establish criteria for the maximum economically feasible rate of rock penetration. The photoelastic technique of experimental stress analysis was the principal method used to obtain the data. Transparent models and transmitted light were employed to investigate patterns in drill-bit models and isotropic materials under the bit when subjected to a concentrated static load. Comparative stress data for anisotropic rock were obtained by the reflective photoelastic technique. Brittle lacquer and an extensometer were used obtain supplementary information wherever substantiating data were desired to check photoelastic results. The zone of maximum shear occurs along an arc near the contact face of the bit. The stress distribution pattern in an isotropic model rock near the area contacted by the bit was nearly a mirror image of that exhibited within a similar areal zone of the bit. The stress pattern in granodiorite specimens was similar, though not symmetric, to the pattern in the isotropic model rock. The asymmetry of the stress pattern in the granodiorite was attributed to the anisotropic characteristics of the constituent minerals of various sizes.

Jan 1, 1963

By Thomas M. Barczak

The U.s. Bureau of Mines is conducting research to optimize the utilization and design of mine roof support systems. This report describes methods to evaluate resultant loading on longwall shields, defined as external resultant vertical and horizontal force acting on the canopy and base. Four models are considered: two rigid-body models, an elastic model, and a numerical model. The rigid-body models equate measured internal shield forces to unknown external resultant shield forces (loads) through rigid-body analysis of static equilibrium requirements. The elastic model develops a solution to shield mechanics by evaluation of the load-displacement relationship and stiffness characteristics of the support structure. The numerical model is a two-dimensional finite-element representation of a shield structure. Model determination of resultant shield loading is compared to controlled loading of a shield in the Bureau's mine roof simulator. Parameters investigated are shield height, canopy contact configuration, canopy and base horizontal constrainment, and boundary conditions imposed by vertical and horizontal shield displacements. It is concluded that rigid-body models are most applicable to in situ measurement of shield loading. Applications requirements and potential error sources are discussed.

Jan 1, 1990

By Howard E. Parkinson

In 1969, new coal mine health and safety legislation was enacted in the United States. As a result of this legislation, the Department of Interior, Bureau of Mines has carried out communications research aimed at developing whole mine communications for increased safety and efficient operation. The research has advanced and many promising results are now being demonstrated to the mining industry. However, there remains a challenge to further improve wireless communications within the mine workings, and through the overburden above the workings. The objectives for future research and development will be discussed, together with the physical and operational constraints that new mine communication systems must face.

Jan 1, 1973

By M. O. Serbousek

The load-transfer mechanics of fully grouted roof bolts in coal mines have been investigated in laboratory and analytical studies. The purpose of this Bureau of Mines research is to increase understanding and better interpret data from routine field pull tests and to develop a numerical model of a grouted bolt that can be used in a global computer model of a mine roof. Analytical studies using closed-form solutions and finite-element techniques were compared to experimental results. Laboratory work includes variation of bolt length, hole diameter, and grouL type. Pull tests were pel'fol·med on 4-, 2-, and I-ft bolts in holes of 1-and I-3IB-in diameters. Both polyester resin and inorganic grouts were used as the anchorage medium. Strain gauges were installed on the bolts at several locations to observe the rate of load transfer from the bolt through the grout to the rock mass when a force was applied at the bolt end using standard jack pull testing procedures and equipment. The average anchorage length of 4-and 2-ft bolts was 22 in. Grout type and hole size variations did not produce a significant effect on the rate of load transfer from the bolt to the rock.

Jan 1, 1987

By Tracy. L. D.

"Since the introduction of pulverized coal as a substitute fuel for natural gas in the various types of heating furnaces used, in steel mills, a number of fires and explosions have occurred, resulting in the loss of life and property.As one of the primary functions of the Bureau of Mines is to conduct investigations in the utilization of mineral substances with a view to increasing safety in the use thereof, it was deemed advisable to investigate the hazards involved in the industrial use of pulverized coal and, if possible, to devise methods of preventing future accidents arising therefrom. The knowledge of the explosive qualities of coal dust which the Bureau has gained in studies affecting dust explosions in coal mines was of material assistance in these investigations.Several plants were visited in which either fires or explosions had occurred, and data obtained as to the probable cause of the accidents.There was found to exist, among some of those employed about the furnaces, a lack of knowledge of the explosive and inflammable qualities of powdered coal.A small stream of pulverized coal leaking down from a defective joint in a coal transport line did not attract much attention, whereas, had a leak in a natural gas line occurred -wider similar circumstances, no doubt it would have had immediate attention.As a matter of fact, if by any means the duet cloud should come in contact with an open flame or hot metal, the effects would be as disastrous as if it had been gas.This is exceedingly well illustrated by an accident which came to the writer's attention. In the system used at this particular plant, the pulverized coal is transported to the furnace through compressed-air lines. The fuel is fed from a storage bin to a blowing tank in quantities as desired, after which compressed air is admitted and the powdered coal blown to the furnaces. At the time of the accident some repairs were being made to the tank, and it was supposed that the air pressure had been entirely released as the pressure gage stood at zero. There was, however, one or two pounds air pressure remaining and when one of the connections was taken off, a cloud of dust was blown across the room, 30 or 40 feet towards the drier furnace where it came in contact with some live coals. Immediately the entire room was filled with flame which rolled back and forth over a specs 50 feet or so in length."

Apr 1, 1921

This manual provides instructions for installing, operating, and maintaining a protective canopy on the Galis Mfg. Co. roof drill. The instructions are based upon two actual installations: one made in a mine on roof drill, model 300, and one in the factory. The parts list and engineering drawings for the protective canopy are included at the end of the manual. And a discussion of some alternative design concepts is also included. The manual can also be used for retrofitting other roof drills with similar protective canopies. Skilled mechanics can determine if the instructions herein would be applicable to the other roof drills and can determine any necessary modifications if they are not.

Jan 1, 1973

By J. E. Tiffany, Z. C. Gaugler

"In presenting this list of permissible explosives and blasting devices, the Bureau of Mines desires to call attention to pages 20 and 25 outlining the conditions in use under which, and only under which, the explosive or blasting device is permissible.In view of a recent publication recounting trade practice favoring the use of a blasting device without stemming, particular emphasis is placed upon condition 4 on page 20 and condition 2 on page 25. An explosive or a blasting device enumerated in the permissible lists of this Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming.PERMISSIBLE EXPLOSIVES TESTED UNDER SCHEDULE 17CAn active list of permissible explosives was published in October 1938 as part of Bureau of Mines Report of Investigations 3421, under the title ""Active List of Permissible Explosives and. Blasting Devices Approved Prior to June 30, 1938."" This list included 191 brand names.Changes in the list that have been authorized to June 30, 1939, placed 56 additional brands of permissible explosives on the active permissible list as a result of tests, changes in brand names, or transfer from the inactive list. Fifty-seven permissible explosives were transferred from the active to the inactive list. The brand names of four explosives were rescinded curing the year. The present list contains 18G brand names. The brand names of the Permissible explosives placed on the active list are as follows:"

Sep 1, 1939

By C. B. Daellenbach

A prototype particulate size analyzer system was developed that would rapidly determine size distributions of homogeneous and two-mineral materials in the 74-micrometer (200-mesh) to 7-micrometer size range. The system sizes particles in a series of hydrocyclone elutriation steps and senses the weight of the five sized fractions by nuclear attenuation techniques. Size distribution of materials was determined from experimentally developed mathematical relationships that existed between particulate weight and the measured transmittance of gamma rays from an Americium-241 source. In the developmental phases, size distributions of three minerals (quartz, magnetite, and hematite) and a laboratory prepared two-mineral mixture of quartz and magnetite were accurately determined by the prototype system. In later stages of the investigation, semiconcentrates, an intermediate magnetic product from a taconite plant, were evaluated. Using 25-gram feed samples of this industrial material, the analyzer system was found to predict weight percentages for individual size fractions with an accuracy of ±0.85 percent or better at a 95-percent confidence level.

Jan 1, 1974

By R. H. Dickson

This paper, which describes the milling practice of the Verde Central Mines, Inc., is one of a series on milling methods and costs being prepared by the United States Bureau of Mines. GENERAL DESCRIPTION The Verde Central concentrator is located in Walnut Gulch, about 1 mile west of Jerome, Ariz., and on the Jerome-Prescott highway. It is about 1,000 feet distant from the main shaft of the Verde Central mine and treats ore from this mine only. The mill is connected with the main shaft of the mine by a 24-inch gave railway, over which the ore is hauled in 5-cubic yard capacity, rocker, side-dump cars, by a 3-ton Brookville gasoline locomotive.

Jan 1, 1931

By Edward B. Kendall

[This paper is one of a series being prepared far and published by the United States Bureau of Minus describing the methods of mining used and operating costs obtained in producing land and gravel from deposits throughout the United States. This circular describes operations at the Eliot plant of the Pacific Coast Aggregates (Inc.). in Livermore Valley near San Francisco, Calif. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent local expenditures only and not total production posts. It is recognized that publication of total costs might in some instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue.]

Jan 1, 1933

By John R. Shattuck

The Shasta and California Iron-ore deposits are 14 miles northeast of Redding, Shasta County, Calif.; and since 1907 have produced more than 300,000 short tons of exceptionally pure iron ore. Although some ore was mined and smelted from 1907 through the First. World War, most of it has been produced from 1942 through 1945 for use in making heavy ship ballast and concrete anchorages for mines. Irregular masses of magnetite, ranging from lumps of a few tons to pods containing about 25,000 tons, occur associated with skarn near the contact between the McCloud limestone and a younger granitic intrusive. Some of the deposits are low-grade, whereas others are nearly pure magnetite. Selective mining and hand sorting are necessary to produce a high-grade product. Investigation of these deposits by the Bureau of Mines included 2,910 feet of diamond drilling, some surface sampling of the principal mineralized zone and beneficiation tests. Resulting factual data are given in the body of this report.

Jan 1, 1948

By J. J. McClelland

The face area of a continuous mining section of an underground coal mine is the most dangerous area in the mine. Workers there are at nearly twice the risk of death or disabling injury than those in other parts of the mine. Despite extensive training of miners and improved equipment and mining methods, fatality and injury rates have remained constant during the past few years. It is clear that advanced research is necessary to apply new technologies or modify work procedures to solve the continuing problem of the loss of lives and the numerous injuries at the mine face. A U.S. Bureau of Mines research program is developing a Reduced-Exposure Mining System (REMS) that relocates personnel operating the mining machinery at the face away from the hazards to a nearby haven of relative safety. REMS uses proven technologies of computer automation and robotics to help control the operation of the mining machines at the face, while personnel are moved away to a nearby, safe control room. In this protected, well-ventilated environment, they can supervise or control the operation of the machines while viewing what the machine is doing using video and graphic display monitors.

Jan 1, 1994