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By Walter T. Lewieki

"INTRODUCTION Numerous deposits of iron ore are found in Cherokee, Bartow, Floyd, and Polk Counties in northwest Georgia. The deposits are generally small and irregular in shape. The ore is usually referred to as ""brown ore"" and is predominately limonite. The crude or ""bank ore"" has to be washed and concentrated before being shipped.The proximity of the deposits to the Birmingham furnaces and a favorable freight differential permit the operation of many deposits that otherwise would be uneconomical. The district produced 413,468 long tons of brown-ore concentrates, averaging 45.53 percent iron in 1943.The necessity of developing additional iron-ore reserves for the war energeucy to supplement the production of the Birmingham district, prompted the Bureau of Mines to initiate exploration of the more promising northwest Georgia deposits. Thirteen properties in the four counties were explored during the program (fig. 1).HISTORY AND PRODUCTIONSeveral furnaces were operated in the district until the early 1900's, ranging from charcoal furnaces to more modern plants with capacities up to 50 tons of pig iron. No furnaces have operated for about 40 years, the product being shipped to Alabama and Tennessee.Bartow County iron mining is declining, although formerly it was the principal producer of the district. Most of the known merchantable ore deposits have been exhausted. For the past 3 years the Mitchell-Hodge mine has annually produced about 225,000 long tons of concentrates containing 46 to 43 percent iron and at present is the only large producer in Bartow County."

Jan 1, 1946

By Richard S. Fowkes

This Bureau of Mines report describes the Human Factors in Mining Search System (HFMSS), a computerized information retrieval system that provides relevant human factors information from journal articles, research reports, seminars, conferences, etc. in terms of 19 mining-related categories. It is the only existing data base that stresses all of the areas of human factors as applied to mining. Examples of these categories are biomechanics and work physiology, human error and human reliability, work design and task analysis, manual materials handling and back injuries, hand tools, organizational and management practices, psychological factors, and training. Although the emphasis is on literature dealing directly with mining, applicable material from other areas of research is included for those categories in which little research has been done in mining. Each record in HFMSS can be recalled by any field such as title, author, date, source, descriptive terms or key words, as well as by any words found in an abstract that describes the purpose, procedure, and results of the research. This report describes HFMSS fields and subject categories, the annotated bibliography, user's manual, and thesaurus of key words. Example printouts in both brief and full formats are included as an appendix.

Jan 1, 1990

By Clarence Hall, J. J. Rutledge

Many of the fatal accidents in coal mines have resulted from the Explosives used in Use of explosives for breaking down the coal. These accidents have resulted both from the use of explo- sives that were not suitable and from the careless or improper use of suitable explosives. Investigation has shown that one of the commonest causes of dis- astrous explosions in the coal mines in this country has been a blown- out shot of black blasting powder or dynamite. The dangers that attend the use of these explosives were perceived several years ago, and in consequence the attention of powder manufacturers was directed to the production of explosives that would be less liable to ignite inflammable gas or dust. The manufacturers have been so successful in their efforts that it is now possible to obtain explosives which yield much shorter and quicker flames than black blasting powder or dynamite, and hence are much less dangerous to use in fiery or dusty coal mines. of explosives. To find out which of the many grades of short-flame explosives Government tests have the qualities that render an explosive most effective and least dangerous for mining coal, the United States Government established a testing station at Pitts- burgh, Pa., in 1908. This station is now under the charge of the Federal Bureau of Mines. Before the station was opened a state- ment of the requirements that the explosives in question would have to satisfy was drawn up and sent to manufacturers. A number of these sent explosives to be tested, and on May 15, 1909, a list of the explosives that had passed the tests was published. Since that date other brands of explosives have been tested and three more lists have been issued. The latest list, published in Miners' Cir- cular 2, Bureau of Mines, contained the names of no less than 71 explosives that had passed the tests prior to January 1, 1911.

Jan 1, 1912

By C. Melvin Lepper

Microseismic energy is generated when stresses accumulated in rock formations are released in the form of fracturing. The acoustic emissions resulting from these rock fractures and movements are detectable as velocity signals in the earth near the energy source. A Bureau of Mines microseismic system that is capable of detecting the acoustic emissions from pit slope movements is described. The digital circuitry incorporated in the system allows a microprocessor program to immediately calculate and present the location coordinates for the seismic energy source in the mine pit wall. This monitoring system is compact, portable, reliable, and relatively inexpensive and rapidly provides accurate information to the mine operators about the stability of a pit slope.

Jan 1, 1982

By W. A. Calhoun, M. M. Fine

"One of the most important wartime activities of the Bureau of Mines was the search for new sources of mineral necessary to the prosecution of the war. Part of that effort was in the form of metallurgical service extended to other government agencies engaged in purchasing and stock piling some of the more critical and strategic materials.Fluorite was one of the materials stock piled by the Metals Reserve Company. The fluorite was usually in the form of coarse metallurgical con¬centrate purchased in the United States and abroad. The material was stock¬piled to insure an adequate reserve of fluorite for the metallurgical industries. The domestic production of metallurgical fluorite containing a minimum effective calcium fluoride content of 55 percent,4/ however, gradually increased until production was at least equal to consumption. The stock-piled metallurgical fluorite, therefore, soon became a surplus commodity.On the other hand, the supply of acid-grade fluorite, containing a minimum of 97.5 percent calcium fluoride and n maximum of 1.5 percent silica,5/ was never entirely adequate. Increased consumption of acid-grade material in the aluminum, petroleum, and chemical industries kept that material on the critical list during the war.Under the circumstances, it was felt that a study of the possibility of producing acid-grade fluorite from the metallurgical stock piles would be of some benefit to the war effort. Consequently, samples of fluorite from several of the Metals Reserve Company stock piles were tested by the Bureau of Mines at the request of the War Production Board.Two groups of samples were submitted for testing. One consisted of metallurgical fluorite purchased from Mexico and stock-piled in the El Paso and Laredo, Texas, stock piles of the Metals Reserve Company. The second group of samples was from the stock piles at Gila, N. Mex.The sample submitted from the El Paso stock pile consisted of about 5,000 pounds of minus 4-inch material. Mineralogically, the sample consisted of fluorite contaminated by calcite, chert, quartz, and small amounts of iron and alumina. Although some of the fluorite was reasonably free from gangue at minus 1-inch, much of it remained locked in sizes as fine as 65-mesh.The Laredo sample was about 5,000 pounds of material from five different piles. The samples from each stock pile, A to E, inclusive, were analyzed separately to determine whether the grade of the material in the piles varied markedly. As there was little difference in the analyses, the samples were combined in proportion to the tonnage represented to make a composite sample for testing. The composite sample consisted of fluorite with small amounts of quartz, calcite, and barite. Most of the fluorite was the dark-colored, opaque variety. A small amount of iron-oxide staining was present, and traces of muscovite, clay, pyrite, and tourmaline were noted. The quartz was present as crystals in vugs, and as finely disseminated grains in the fluorite. The druzy quartz and the calcite were free at minus 10-mesh, but the disseminated grains, some of which were 1 to 15 microns in size, were not entirely free at minus 270-mesh. A petrographic estimate indicated that 65 percent of the silica was locked in the 150- to 200-mesh."

Jun 1, 1946

This is the fourth in a series of reports on properties of commercial motor fuels, made in accordance with a cooperative agreement between the Cooperative Fuel Research (C.F.R.) Committee and the Bureau of Mines of the Department of the Interior. The first report gave data on motor gasolines sold during the winter of 1935-363/. The second report gave the same data? for motor gasolines sold during the summer of 19364/. The third report of the series gave the same data for motor gasolines sold during the winter of 1936-375/. This report covers 63 brands of gasoline represented by 1,136 samples excluding the Pacific Coast. Those from the Pacific Coast were averaged by the Pacific Coast technical group before being submitted and are published exactly as they were submitted. In some areas reports were received from five or six companies on the same brands of gasoline, whereas in other areas only one company reported on a brand. Thus, it can be seen that some of the data are more representative than others.

Jan 1, 1937

This is the fourth in a series of reports on properties of commercial motor fuels, made in accordance with a cooperative agreement between the Cooperative Fuel Research (C.F.R.) Committee and the Bureau of Mines of the Department of the Interior. The first report gave data on motor gasolines sold during the winter of 1935-363/. The second report gave the same data for motor gasolines sold during the summer of 19363/. The third report of the seriis gave the same data for motor gasolines sold during the winter of 1936-375/. This report covers 63 brands of gasoline represented by 1,136 samples excluding the Pacific Coast. Those from the Pacific Coast were averaged by the Pacific Coast technical group before being submitted and are published exactly as they were submitted. In some areas reports were received from five or six companies on the same brands of gasoline, whereas in other areas only one company reported on a brand. Thus, it can be seen that some of the data are more representative that others.

Jan 1, 1937

By W. F. Wyman, S. F. Ravitz

"INTRODUCTION By far the greater part of the high-grade manganese ore used in the United States is imported from overseas. During the early part of the recent World War importations of manganese ore were seriously threated, and it appeared that it would be necessary to utilize low-grade domestic ores to the fullest possible extent. Among the processes that appeared to offer the best possibilities for beneficating low-grade domestic oxide manganese ores, which ordinarily are net readily amenable concentration by ore-dressing methods, were those involving leaching with sulfur dioxide. The Bureau of Mines therefore investigated the amenability of a large number of such ores to sulfur dioxide leaching.Several sulfur dioxide processes for beneficiating low-grade oxide manganese ores have been proposed. 3/ One of these, based on a patent by Van Arsdale and Maier, 4/ was used recently in a plant constructed to treat 1,000 tons per day of 20-percent manganese ore from the Three Kids deposit near Las Vegas, Nev. 5/ In this process the ore slurry is leached with sulfur dioxide gas, the resulting solution is evaporated to crystallize the manganese sulfate, the crystals are decomposed thermally to produce high-grade manganese oxide and regenerate sulfur dioxide, and the manganese oxide product is nodulized. The Bureau of Mines has recently developed a process 6/ in which a suspension of the ore in calcium dithionate solution is leached with dilute S02 gas, the manganese is recovered from the resulting solution by a simple lime precipitation, and the precipitate is nodulized or sintered to form a high-grade manga¬nese oxide product."

Jun 1, 1947

By Paul L. Michael

This report presents a discussion of perforance parameters for electronic or active hearing protectors that will meet the needs of underground coal miners. This information is incorporated into a proposed set of specifications that can be used to judge the suitability of a particular electronic hearing protector for the coal mine application. Acoustic and electrical tests were performed on a developmental model of an electronic hearing protector built by the U. S. Bureau of Mines. This model showed only a slight reduction in speech intelligibility which was traced to poorly matched components and in particular to the transducers. Tests of alternative components showed the Knowles BL-1671 microphone to be suitable for this application because of its performance and extremely small size. The Roan-well H-143/AIC earphone was found to have a good frequency response but has the disadvantage of being rather bulky which causes a slight degradation of a low frequency attenuation of the hearing protector. A satisfactory installation of these components in a hearing protector muff was demonstrated and tested. Results of tests of several methods of controlling the sound level under the hearing protector muff showed that a simple diode clipper circuit can be used with only a negligible loss in speech intelligibility for normal-hearing listeners. A commercially available active hearing protector, the British-built ACOS A-9000/2 was examined. This hearing protector provides sound level limiting through a saturating amplifier. Preliminary tests have shown that the performance characteristics of this commercial unit meet many of the proposed specifications so further testing and evaluation should be performed to determine its suitability for use 1n underground coal mines. The recommended test of intelligibility for electronic hearing protectors and other communication systems as used in a coal mine setting is the Modified Rhyme Test (MRT) developed by House et al. in 1965. The suitability and method of administering this test are discussed.

Jan 1, 1976

By V. A. Danielson

The Bureau of Mines studied waste disposal methods a1 a coal mine in Kentucky and another in Alabama to develop cost estimates, to provide better knowledge of current practices, and to guide consideration of alternate disposal methods. Costs of the existing waste disposal systems at each mine were estimated using present-day costs of equipment and labor. Costs of waste disposal systems using alternate equipment were also estimated. Although total disposal costs were essentially the same for both operations, reclamation costs will differ because of different reclamation practices.

Jan 1, 1969

By David C. Byrne

PURPOSE: Evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. RESEARCH SUMMARY: The results of previous NIOSH research show that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals and that miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and gender. Using hearing thresholds at 4,000 Hz as an indicator, coal miners experience hearing loss 2.5 to 3 times greater than would be expected for persons not exposed to occupational noise. At age 50, 90% of coal miners and 49% of metal/nonmetal miners were found to have a hearing impairment. In comparison, only 9% of a nonoccupationally exposed control group had a hearing impairment at age 50. There are numerous barriers to the prevention of hearing loss among miners. In an effort to overcome some of these obstacles, this work was initiated to evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. Experiments will involve analysis of this new technology under both laboratory and field conditions. Laboratory components will consist of controlled studies using an anthropometrically correct test fixture as well as human subjects to evaluate the adequacy/effectiveness of various hearing protective devices. Electroacoustical performance testing of new noise monitors will also be conducted in a laboratory setting. Subsequent field studies will determine the actual usefulness and practicality of the personal protective/monitoring equipment as used in different mining situations. It is anticipated that increased on-the-spot awareness of hazardous noise levels and the availability of better-suited hearing protectors will provide a degree of protection beyond what is currently attained in different mining environments. Therefore, the intent of this project is to identify and adapt new acoustical technologies and products that have a direct application to individual mine workers. With increased knowledge of these technological advances, a greater demand for similar devices will likely occur, which, in turn, will lead to a better understanding and awareness of hearing loss prevention methods throughout the mining community. The ultimate goal is for widespread integration of useful hearing loss prevention products and devices into the daily routines of miners

Jan 2, 2000

By Luis v. Coppa

Since its inception in 1910, the Bureau of Mines has been the principal Federal agency involved in ore reserve estimations, using such traditional methods as polygons of influence and variations of inverse distance weighting While adequate for estimating the average are grades in a mining block or section, these methods do mot, however, provide a consistent way of quantifying the reliability of the estimates. This report describes a technique for enhancing ore reserve estimations using geostatistics, the methodology of which combines the spatial and random aspects of geologic phenomena into a formal theoretical framework for deriving the estimation variance of ore reserves. Correctly used, geostatistics enables confidence intervals to be placed around ore reserve estimates calculated from drill hole data. A geostatistical software system was obtained -From the U.S. Geological Survey and installed, aster slight modifications, on the Bureau's Wang computer. System testing and validation was conducted using a simple cast-book-type example. This was then followed by variogram analysis, point kriging and block kriging of data from a previously worked section of a uranium mine.

Jan 1, 1984

The Bureau of Mines has conducted considerable research to improve life support technology for underground mining applications. This proceedings volume presents several new developments that may help increase the chances of mine workers in surviving underground disasters. Several papers address the performance of present self-contained self-rescuers (SCSR's) and provide proposed guidelines for the design and testing of a second-generation SCSR. Improvements In the safety and effectiveness of mine rescue and recovery operations are described, including the design of a low-profile rescue breathing apparatus and a rescue team helmet.

Jan 1, 1987

By W. C. Holliman

This report is one of a series of reports on the characteristics of commercial aviation gasolines, It presents compilations of inspection test data on their products furnished by 16 manufacturers of commercial grades of aviation and special date obtained in Bureau of Mines laboratories on 66 samples of these gasolines, Data are presented for 19 samples of grade SO, 17 of grade 91/98, 22 of grade 100/130, and 8 of grade 115/145 aviation fuels. These gasolines are designated July 1948 production, although some of the samples may have been produced a month earlier or later.

Jan 1, 1948

By Lijun Xu, Jan M. Mutmansky

"Mutmansky, J.M. and· Lijun Xu, 1989. Some observations on particulates collected in underground coal mines using diesel and non-diesel equipment. Min. Sci. Technol., 9: 207-218.The results obtained when sampling twenty underground coal mine sections, each in a different mine, are outlined. The sampling effort was oriented toward a detailed characterization of coal mine dusts and thus eight-stage Anderson Model 298 impactors were used as the primary collection instrument. This instrument allowed a fairly detailed size distribution for each of the particulates sampled. Because four of the mines used diesel outby equipment and/or diesel shuttle cars at the face, it is possible to make some comparisons of the particulate distributions in diesel versus non-diesel mines.One of the more interesting results is the pattern that exists in mines lising diesels only for outby utility haulage. Particulates in these mines seem to be consistently heavy in the fine size ranges, perhaps being of significant concern to the industry. While no definite conclusions can be drawn from the limited data, a more detailed study of particulates may provide a better picture of particulate loadings.IntroductionThe subject of particulate emiss1ons from underground diesel equipment is currently a very important topic as health concerns and regulation of diesel particulate emissions have created new environmental problems for mine operators. The amount of particulate matter originating from diesels has not been extensively measured and problems of differentiating coal and mineral dust from diesel particulates make existing data questionable.However, it is necessary to make an assessment of the problem in order to solve it. It is known that particulates from diesel engines are solid aerosols formed in the combustion process. Technically, this places the particles in the category of fumes. It is also known from tests where no mineral dust could be a factor in the measurements that about 90% of diesel particles are less than 1 µm in aerodynamic diameter [3]. To measure the diesel component of a coal/diesel particulate to measure, Johnson et al. [2] have developed procedures for utilizing laser Raman spectroscopy. The determination of diesel content in a coal/diesel mixture is difficult due to the chemical similarity of the two organic materials. However, laser Raman spectroscopy, which is often used for identification of organic materials, has potential if the Raman spectra for the two materials are different and unique. The study concluded that an accuracy of ±~% could be achieved for mixtures containing up to 55% diesel particulate. The method is relatively complex and would need further development for routine application."

Jan 1, 1990

By R. S. Dean, John Gross

"In a preliminary report made a year ago it was shown that certain minerals when subjected to heating with water under high pressure and temperature were shattered upon the sudden release of that pressure. The main feature in which the results of this method differ from those of conventional grinding is in the differential effect obtained. The more metallic minerals, and hence the valuable minerals, are shattered more readily than are the gangue minerals. In other words, explosive shattering is unique among possible methods for comminuting an ore in that it wastes the least energy on the useless part of the ore. Explosive shattering, therefore, offers possibilities as a means for reducing grinding costs, arid it is this potential advantage of the process that makes it worthy of further experimental study. The first part of this paper is devoted to a study of the mechanism of the process; the, second part reports results obtained in toots on a selected list of ores to exhibit some of the advantages of explosive shattering."

Feb 1, 1933

By Martin Berman

Tables of 28 positions for all the transitions for nine common analyzing crystals for first, second, and third order reflections were compiled by the Bureau of Mines to facilitate elemental X-ray fluorescence analysis on multi-element systems. The tables are based on a compatible set of wavelengths for 2,346 observed X-ray transitions of the elements lithium to americium. The results are tabulated in order of increasing wavelength as well as by increasing wavelength for each element.

Jan 1, 1969

By Alan A. Bergeron, J. L. Michels, R. L. Collins

Advanced communication and monitoring systems were developed and demonstrated in three underground mines representing different mining techniques, geographical areas, and material mined. The first mine was a large coal mine in western Pennsylvania that used room and pillar techniques and continuous mining methods. The system developed for this mine provided private telephone channels, environmental monitoring, and control of underground equipment, all on a single coaxial cable, with all system operations under the direction of a minicomputer. Many advanced features were incorporated into the system, such as paging of roving personnel, two-way section wireless, through-the-earth emergency communication, and redundant signal paths. Television was multiplexed into the system for underground equipment surveillance. A hoist radio system completed the complement of equipment at the mine. The second mine was a magnetite ore mine in eastern Pennsylvania that used block caving mining techniques. A radio system was developed that provided two-way communications between trackless vehicles and roving personnel. A unique system of uhf/vhf repeaters combined with a flleaky-feeder" transmission line offered operational and emergency features not previously found in mine communication systems. Evacuation alarming, personnel paging, fan-hole drill operator communications, and maintenance and safety vehicle dispatch were provided. The system required no dispatcher and operated during power failure. A hoist communications/shaft inspection system completed the installation. The third mine was a deep silver mine in the Cour d’Alene district of Idaho. The system developed for this mine utilizes a single wire pair to provide up to 14 voice channels. A unique combination of PBX, telephone carrier system, and intercoms offered private conversations, selective signaling, and emergency backup communications. Two hoist communication systems were installed to provide a voice link and in-cage belling signal between hoistman and cage.

Jan 11, 1981

By James E. Norman

[The flotation of mica is mentioned frequently in the literature, but must of the references have dealt with the recovery of mica by the old anionic collectors. The first use of the new cationic reagents indicated their superiority- as collectors in the flotation and a. agglomerate tabling of micas, feldspars, quartz, clay, and other acidic mineral, but the separation n of these minerals from each other necessitated study of the flotation of each mineral.]

Jan 1, 1941

By James E. Norman

[The flotation of mica is mentioned frequently in the literature, but most of the references have dealt with the recovery of mica by the old anionic collectors. The first use of the new cationic reagents indicated their superiority as collectors in the flotation and agglomerate tabling of micas, feldspars, guartz, clay, and other acidic minerals, but the separation of these minerals from each other necessitated of the study of the flotation of each mineral.]

Jan 1, 1941