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By Luis Angel De Montreuil

Ante el problema del tratamiento de minerales complejos, la demanda de eficiencia metalúrgica y bajos costos de operación, el ingeniero busca el apoyo de la mineragrafía como estudio microscópico de los minerales económicos. En ese sentido, el presente texto señala la importancia de la minegrafía -en tanto ayuda a la flotación de los sulfuros valiosos de los yacimientos peruanos. Asimismo determina las propiedades de los minerales con el fin de identificarlos.

Jan 1, 1986

By M. Q. W. Jones

This paper presents a compilation of physical properties of rocks from the Bushveld Complex. The database consists of more than 900 measurements each of thermal conductivity and density. The data are well distributed from localities around the Complex and most rock types are well represented. Thermal conductivity and density are shown to vary widely in the ranges 1.8-4.2 W m-1K-1and 2600-4200 kg m-3respectively. Although only 190 heat capacity measurements are available, this parameter is quite uniform for most rock types present, 800-900 J kg-1K-1, except for chromitite, which has a lower average, 750 J kg-1K-1. Rocks encountered in deep platinum mines are particularly well characterized and this has important implications for prediction of mine refrigeration requirements. The heat flux into a semi-infinite region with properties typical of the Bushveld Complex as a function of time is substantially lower than an equivalent model for the Witwatersrand Basin.

Jan 1, 2015

By W. J. Fene, G. W. Grove

An important activity of the Safety Division of the Bureau of Mines , in its efforts to reduce accidents , is the safety inspection of mines . Inspections are made at the request of the operators and are not connected with the inspections by the various State departments of mines . The operating management is furnished with a confidential report of the results of the Bureau's inspections , with recommendations for elimination of the hazards found . These mine - safety inspections include a study of mining practices , conditions , and equipment and in some cases the sampling and analysis of mine air and coal dust . The Bureau of Mines has no regulatory powers , therefore the recommendations made in these reports are merely suggestions , and operators are not required to adopt them . Mine inspections are a check on safety standards , methods , and practices and are essential to any accident -prevention program . A foreman or superintendent may be sincere in his efforts to operate a mine safely and believe that he has done everything possible to attain this end . However , experience has shown that because of his familiarity with the mine and the consequent " nearness " of its various features many unsafe conditions may be , and in most cases are , overlooked ; an inspector , particularly an outsider who is trained to look for hazards , can point out the unsafe conditions overlooked by the foreman or superintendent . Some companies employ safety engineers who make regular inspections of their mines , report substandard conditions and hazards found , and make recommendations for correcting them . Unless these recommendations are carried out the inspections have little value . In making recommendations , due consideration should be given to the feasibility of carrying them out ; the management may and very often does consider a recommendation impracticable because of the

Mar 1, 1935

By D. Pappas

Over the past decade the number of contractors working in underground coal mines has nearly doubled; however, the effect this has had on the industry?s injury rates has been the subject of much speculation. The confusion exists because the U.S. Mine Safety and Health Administration (MSHA) database does not assign contractor hours to the individual mining operations where they worked. To better understand the safety record of the contractor segment of the industry, the National Institute for Occupational Safety and Health (NIOSH) undertook a comprehensive analysis of the data contained in the MSHA database. The first part of the study compared overall contractor and operator trends from 1983 to 2009 related to employment, hours worked, injury rate, and days lost. One unexpected finding was that the larger contractors tended to have higher injury rates than the smaller ones. The second part of the study directly addressed the role of contractors on the safety record of 10 large underground coal mines. A detailed analysis provided both injuries and estimated contractor hours worked at these mines for the period 1992?2007. Comparison between the estimated contractor injury rates and the reported operator injury rates at these mines indicated that the contractor injury rates were significantly higher at most of the operations studied. However, the industry-wide data indicates that contractor and operator injury rates have converged since 2005 and are now equivalent.

Jan 1, 2011

By G. E. McElroy

[The ventilation of development faces in mines for diluting gas or dust concentrations aid in hot mines for providing air-motion cooling affect, by fan-pipe units discharging high-velocity streams of air close to the face, is an important phase of mitre ventilation. The effectiveness of such units depends largely on the air-flow distribution between-the pipe discharge said the face, a subject on which little definite information is available. A study of the air, flow from grills into rooms3/ has provided sore basic data, but under conditions so different from mine fan-pipe installations in development ends that tae data to are of doubtful application to mine installa¬tions, owing to differences in air-flow conditions. The purposes of this report is to present and discuss the results of an initial series of tests of a general investigation designed to yield definite laws and design data for the discharge of fan-pine lines in nines. The s series was planned to yield preliminary data on the effects of velocity of discharge, size and shape of tripe, and adjacent calls on the air-flow distribution. Tents were made on 10-inch pine with seven different end conditions and one change of wall condition. Changes in size and shape of discharge wore made b y short transformation pieces directly at the discharge end, with the result that effects due to contraction and expansion of the flow, which proved to be of much greater importance than was expected, totally obscured any normal effects cue to size anti shape. The results of this series of tests, therefore, relate to 10-inch pipe with various discharge designs is and ago se reported.]

Jan 1, 1940

By E. A. Hewitt

This paper describing the mining practices at the Park Utah mine in the Park City district is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The Park Utah mine is situated at Keetly, Utah, about 5 miles east of Park City. The Park City district lies on the eastern slope of the Wasatch Mountains, 25 miles southeast of Salt Lake City. The district embraces a tract located between the crest of the main range on the west and the mountain meadows along the eastern foothills. The elevation of the Union Pacific Railroad station at Park City is 7,000 feet above sea level. The town and mines are served by two railroads; one 28 miles long is a branch of the Union Pacific Railroad and connects with the main line at Echo Junction, east of Ogden; the other is 35 miles long and joins the Denver & Rio Grande Western Railroad at Salt Lake City. The district and mines are also accessible by excellent automobile roads from Salt Lake City and surrounding points (fig. 1).

Jan 1, 1930

By W. Dingley, G. R. Hoey

"Thirteen Canadian sulphide ore mines were surveyed for corrosion control. The mines visited were a small, yet representative, proportion of this segment of the Canadian mining and metallurgical industry. Information on metallic corrosion and methods used to control it in underground workings and mills was gathered (a) by discussing corrosion problems with company personnel, (b) by examining equipment and structures during under-ground and mill tours, (c) by photographing corrosion sites, and (d) by collecting and analyzing mine water samples.The corrosion survey, which is summarized in the re-port, leads to the following general conclusions. Mine environments are corrosive, particularly when the mine w1a-ter is acidic. Because of a lack of good corrosion control measures, excessive deterioration of equipment due to corrosion occurs in mines. Mill environments are also corrosive, but in some cases good preventive measures are being taken to effectively control corrosion losses.Ways to reduce corrosion losses in sulphide ore mines and mills are discussed. The main areas for more corrosion research and development are selection of materials of construction, protective coatings, cathodic protection, inhibitors, equipment design, and mining and milling practices."

Jan 1, 1971

By Xiaoping Xu

An albitization granite type tantalum-niobium ore from Jiangxi Province, China was taken as the research object in this paper. The main valuable minerals in this ore are tantalite-columbite and uranmicrolite, and the minerals that can be comprehensively recovered include cassiterite, sulfide minerals, topaz, zinnwaldite, and quartz-feldspar. Based on the research results of process mineralogy, the roughing process of gravity separation for coarse particles combined with flotation for fine particles is proposed. The combined cleaning process of flotation-gravity-magnetic-electric-hydrometallurgical separation is adopted for the rough concentrate of gravity separation while the combined cleaning process of gravity-flotation- hydrometallurgical separation is adopted for the rough concentrate of flotation. High intensity magnetic separation is used to separate and recover zinnwaldite and quartz-feldspar from gravity tailings. By mineral processing for the crude ore containing (TaNb)cassiterite concentrate is 0.0003% with a grade of Sn 63.22% and a recovery of Sn 47.42% while the yield of sulfide concentrate is 0.0783% with a grade of Pb 33.15% and Zn 27.09% which can be separated to get lead and zinc concentrate respectively. The yield of topaz concentrate is 0.1545% and the topaz mainly distributed in the size range of -0.4+0.074mm, which can be made into abrasive products of different particle sizes after classification. The yield of zinnwaldite concentrate is 16.91% with a grade of Liwhiteness of 75%, which is a glass-ceramic material of good quality. 2O5 0.0346%, Sn 0.04%, Pb 0.10% and Zn 0.33%, the tantalum-niobium concentrate with a yield of 0.00278%,a grade of (TaNb)2O5 53.61% and a recovery of (TaNb)2O5 44.49% is obtained. And the yield of 2O 1.34% and Rb2O 0.40%. The yield of quartz-feldspar concentrate is 30.42% with a grade of K2O+Na2O 8.98% and Fe2O3 0.11% and a natural All of tantalum, niobium, cassiterite, topaz, zinnwaldite, quartz, and feldspar are recovered effectively. Keywords: tantalum-niobium ore, gravity separation for coarse particles, flotation for fine particles, comprehensive recovery

Sep 1, 2012

By A M. Nyembwe, A M. Garbers-Craig, R Cromarty

With the depletion of high-grade lump iron ore, concentrates have been identified as an alternative material for sinter making. Adding concentrates to the sinter mixture reduces sinter bed porosity and gas flow through the sinter bed. This will result in lower sinter strand productivity. A potential solution to this problem is to add concentrate in the form of micropellets. This study investigates the effect of concentrate and micropellet additions on the permeability of the sinter mixture. Permeability was measured on sinter mixtures containing ten to 40 per cent concentrates and micropellets at various moisture contents. The effect of concentrate and micropellet addition on the permeability–moisture relationship was examined. The results confirmed that the addition of concentrates into the sinter mix decreases the maximum permeability of the sinter bed. The incorporation of micropellets into the sinter mix reduced the permeability less than concentrate addition. The study also showed that the maximum permeability of sinter mixes containing concentrate is reached at the same moisture content as the sinter mixture without concentrate addition. For sinter mixes containing micropellets, additional water must be added to obtain maximum permeability. Parameters including the granule size, void fraction and angle of repose were also investigated to evaluate their effects on the sinter bed permeability.CITATION:Nyembwe, A M, Cromarty, R and Garbers-Craig, A M, 2015. Effect of concentrate and micropellet addition on iron ore sinter bed permeability, in Proceedings Iron Ore 2015, pp 69–76 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By Tom Retka

This three volume final report summarizes the activities and conclusions of this contract. The objective of the contract was to develop noise control modifications on a retrofit basis, for auger miner coal-cutting systems. Manuals were prepared to assist mine shop personnel in retrofitting the auger miner with these noise controls. Final Report Volume I - Details all vibration and acoustical tests conducted in development of the noise controls. Final Report Volume II - Noise Control Modification Manual for the Jeffrey 100-L Auger Miner describes the various noise control modifications to the auger miner, along with fabrication procedures, cost and vendor information. Final Report Volume III - Noise Control Modification Manual for the Jeffrey 94-L Bridge Conveyor describes the various noise control modifications to the bridge conveyor, along with fabrication procedures, cost and vendor information.

Jan 1, 1978

By F. J. Plecity, J. T. Michalak, W. C. Leslie

Isothermal recrystallization and grain growth in zone- and vacuum-melted irons and Fe-Mn alloys, up to 0.60 pct Mn, were studied in the range 480° to 650° C, after 60 pct cold reduction. In initial stages, rate of grain growth and rate of recrystallization of iron decrease with time. The recrystallization is typical of a growth-controlled process, and rate of growth is determined by the extent of recovery. Mn decreases rates of growth and of recrystallizatzon. The recrystallization process changes at about 0.30 pct Mn and nucleation may become time-depetzdet~t. In recent years, considerable effort has been expended in determining the effects of solute elements on recrystallization and boundary migration in fcc metals. The results have indicated that the effects produced by single solute additions are dependent upon both the element added and its concentration.'-' In contrast, there have been very few attempts to determine the characteristics of recrystallization and boundary migration in high-purity bcc metals, especially after heavy deformation, and the effects thereon of single solute elements.9-11 This study was undertaken to determine the recrystallization characteristics of various "high-purity" irons and the effects of manganese additions at two levels of base purity. It was hoped that the information obtained would improve our understanding of the recrystallization of pure metals and aid in formulating a theory for the effect of solute elements. The interest was not entirely academic, for the annealing of low-carbon steels, which is of very great commercial importance, is but poorly understood. MATERIALS The compositions of the irons and iron-manganese alloys used are listed in Table I. The zone-melted iron and Fe-Mn alloys were made by Battelle Memorial Institute. Iron S-1 was arc-melted in a water-cooled steel mold in an argon atmosphere. The ingot was forged into a bar, then given two horizontal zone-refining passes in an alumina boat. Iron V-4 was treated in a similar manner, but was not zone-refined. The iron for the zone-melted Fe-Mn alloys was induction melted in vacuum in MgO crucibles and cast into alumina molds. The ingots were forged into bars, machined to shape, and a groove milled down one side of each. The best available electrolytic Mn was placed in the grooves, and the bars were zone melted. The vacuum-melted Fe-Mn alloys were induction melted in this Laboratory in MgO crucibles and poured into cast-iron molds. Iron V-5 was purchased from National Research Corp. in the form of a small vacuum-cast ingot. The low-carbon steel was made by induction melting in air at the U.S. Steel Corp. Applied Research Laboratory. The history of the materials prior to the final cold reduction differed; these details are given in the Appendix. The penultimate grain size of the principal materials was kept in the range ASTM 2 to 4, except for the low-carbon steel. PROCEDURES The cold work prior to the final recrystallization anneal was kept constant at 60 pct. It is known that rolling procedure can influence the kinetics of recrystallization of ironI2; therefore, all specimens were rolled in one direction only, between clean,

Jan 1, 1962

By S. L. May

The Bureau of Mines has developed several methods for extracting tantalum and columbium (niobium) and the rare-earth compounds from ores and concentrates. A cooperative agreement was made by the Bureau with Porter Bros. Corporation of Idaho to process 200 pounds of its euxenite concentrate by methods that had been developed at the Albany, Oreg., Metallurgy Research Center. The euxenite concentrate was processed to extract and purify the valuable metals by chlorination, solvent extraction, and hydrometallurgical techniques. Chlorination was used to convert the valuable constituents into chlorides and to partly separate them. Solvent extraction techniques were used to separate the tantalum from the columbium. The rare-earth and uranium compounds were purified by hydrometallurgical methods.

Jan 1, 1959

The energy input requirement to produce the molten slag associated with iron production to the modern Australian blast furnace, is estimated to be 2.OMJ/kg. In converting blast furnace slag to products of higher commercial value, advantage should be taken of this energy content by transporting molten slag from the furnace for beneficiation and processing in the molten state at an "off furnace site". The refined slag melt may then be converted into a variety of products for use in the building and construction industries, e.g. slag cement, slag sand and slag aggregates, insulation wool and various slag ceramic products. Some results of studies into slag melt beneficiation and conversion processes involving both molten and cold granular slag raw material, are presented.

Jan 1, 1979

By R. V. Ramani

This report is volume 1 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation, and ventilation. This volume of the final report contains a statement of the purpose and scope of work of the Grant, and provides an overview of the Master Design Simulator with a brief description of each subsystem. Also included is a discussion of several areas of application for the simulator.

Jan 1, 1975

By Karl L. Konnerth

THE rapidly increasing use of machinery for the mining of coal and operations incidental thereto has materially changed conditions from a safety standpoint. A few of the coal-producing states have recognized the need for specialized electrical equipment for use in mines and have introduced certain requirements in their State safety regulations, notably Pennsylvania. This paper discusses the principal problems involved in maintenance of such equipment. PERMISSIBLE: EQUIPMENT "Permissible" electrical equipment is equipment that has met certain prescribed standards for use in mines where hazardous conditions may occur and has been recommended by the U. S. Bureau of Mines. Such machinery is available on the market for most coal-mining operations--for instance, coal cutting, transportation, drilling, loading, working-place illumination, shot-firing and pumping. A notable exception is the trolley-reel gathering locomotive which, although its parts may be explosion-tested by the Bureau, has not been approved as permissible for the following reasons: I. The trailing cable is subjected to more severe service than on other equipment. 2. State regulations do not require that a working place be examined for methane before a locomotive enters it. 3. Even with two-conductor cable, imperfect or inadequate bonding may cause the emission of sparks at the wheels of the locomotive and at rail joints. 4. As the locomotive is equipped with a trolley pole, and as the trolley wire may be installed and used in unsafe territory in spite of rigid State regulations, a trolley-reel gathering locomotive is always a potential hazard. MAINTENANCE The proper procedure for maintenance of permissible equipment may be divided into three parts: (I) inspection, (2) actual maintenance and (3) changes or improvements to existing machines. To secure the fullest benefits through the use of permissible equipment it is necessary that all men involved understand the principles underlying the safety features of this equipment and realize the significance of defects, so that neglect and indifference in the maintenance thereof may be eliminated. Inspection From the standpoint of safety it is desirable no doubt to make a suitable inspection of permissible electrical equipment once a week, but the opening of every enclosed compartment at each inspection may do more harm than good. The openings to such compartments are closed with various types of covers very accurately machined, often made of the softer alloys to reduce weight, and fastened with a multitude of bolts, screws, washers, and other small parts. Frequent handling of these covers may cause sufficient damage to defeat their original purpose and intent.

Jan 1, 1941

By Charles M. Ryder

IN presenting this paper to the Institute I beg to mention, first, the results which I have obtained and the apparatus which I have employed, and to follow this with a brief description of the steps by which I have perfected this process. My present mode of testing is as follows : I obtain, either from the furnace or from the finished product in any stage in which it may chance to be, a small test-piece, usually about 4 of an inch square by 3 1/2 inches in length. I place this test-piece upon the poles of an ordinary electro-magnet, for about one minute, and thus magnetize it to its extreme limit. I then place it upon an indicator (which I will shortly describe), on which indicator there is already placed a piece of steel of similar form which has been magnetized in the same manner, the percentage of carbon of this second piece being definitely known. I then, by means of a scale, which forms part of the indicator, marked in degrees of carbonization, read the exact percentage of carbon contained in the piece under examination. My apparatus consists of an ordinary electro-magnet, connected with a suitable battery of moderate power, by which I magnetize the pieces as before described, and of an indicator which consists of a magnetic needle suitably mounted or suspended, so that it is free to deviate a few degrees only from the zero point, and having a rest, which is used to check the vibrations when in use, and to support its weight when not in use. At a right angle to the natural position of the needle I have a scale about 3 feet long, the zero point of which coincides with the natural position of the needle. This scale is marked in each direction from the zero point in degrees of carbonization. The marking of the scale is in accordance with the following rule: Taking the carbonization of the steel as a basis, I maintain the same proportion between the squares of the distances on the scale as exists between the percentages of carbon in the steel, for instance, if .08 of

Jan 1, 1877

By G. L. Myers

The Fortitude skarn near Battle Mountain, NV is currently one of the largest producing gold skarns in the world. It contains about 11 Mt (12 million st) of minable ore grading 5.14 g/t (0.149 oz per st) and is the distal portion of a continuous skarn system in the Copper Canyon area centered on the Eocene Copper Canyon granodiorite porphyry. Calcsilicate compositions, opaque mineralogy, and the high gold grades are atypical of other base metal skarns (iron, Fe; copper, Cu; lead-zinc, Pb-Zn; or tungsten, W). The Copper Canyon skarn is systematically zoned from a garnet (AD 70-100) dominant, pyroxene (HD 20-45) subordinate zone, with major Cu mineralization, adjacent to the intrusive (West ore body), to a pyroxene (HD20-100) dominant, garnet (AD90-100 cores. AD 30-60 rims)subordinate assemblage, with major Au, near the distal marble front (Fortitude ore body). An extensive biotite ± diopsidic pyroxene ± kspar alteration halo surrounds the pyroxene > garnet gold-bearing skarn and represents the early stages of metasomatic alteration. Retrograde alteration is limited in areal extent and intensity, and consists of actinolite, chlorite, quartz, and prehnite. Economic gold mineralization begins in the pyroxene > garnet zone and continues to the marble front, a distance of 1 to 1.5 km (0.6 to 0.9 miles), respectively, from the plutonic contact. The opaque mineralogy in this gold zone includes pyrrhotite, arsenopyrite, marcasite, minor chalcopyrite, galena, sphalerite, argentite, hessite, hedleyite, volnyskite, and native bismuth and gold. The pyrite-pyrrhotite geothermometer yields temperatures that range from 450° C to 300°C (842° F to 582° F) and the electrum-argentite-sphalerite geothermometer yields temperatures which range from 290°C (554° F) at the marble front to about 420°C (788° F) more proximal to the intrusive. Log fS2 calculations from the sulfide assemblages yield values near - 10 with log fO2 values of about -30, in a solution of near neutral pH (5-6). Calculations of metal solubility suggest that the metals were transported as chloride complexes in the proximal skarn but that bisulfide complexes were predominant within the distal gold skarn. Relatively low oxidation states buffered by the carbonaceous to argilliceous, calcareous protolith and subsequent ferrous iron-rich skarn assemblages appear to have increased the gold carrying capacity of this large hydrothermal system.

Jan 1, 1991

By J. Philip Neal

Feldspar is no example of special mineralization in isolated spots: it can usually be found within a mile or so of almost anywhere. Along with silica sand, it is a major part of our world's total mineral composition. This fact imparts to it an economic status different from a sulfide ore, or potash, or phosphate. While every feldspathic "stringer" does not possess economic potential, the generous distribution does yield a high statistical frequency of good feldspar ore bodies: the adjective "good" being subject to some flexibility of interpretation. The strong chemical bonds of this alkali aluminum silicate give it certain use advantages, but under present technology its individual elements cannot practically be separated to create aluminum, potassium, sodium, silicon - or their oxides. Its present uses rely upon chemical inertness - as in fillers; and on its physical melting characteristics and their effect in glass, enamel, or ceramics.

Jan 1, 1973

By M. R. Geer

The Bureau of Mines surveyed the solid wastes that have accumulated from coal mining in Washington, Oregon, and Montana. Location, amount, character, and condition were determined, and both economic and environmental factors were considered. Areas covered by waste comprise 800 acres in Washington, 5 acres in Oregon, and 1,200 acres in Montana. In a few cases waste is being utilized, particularly cinder from burned refuse dumps, as fill in road construction and as a ceramic raw material. It is estimated that wastes deriving from coal mined for electric power generation by 1974 may amount to 3 million tons of washery refuse, 2.7 million tons of fly ash, and 1,000 acres of spoil banks.

Jan 1, 1969

By J. Hamilton Duffy

This is the first of, a series of papers describing dredging methods and costs in recovering sand and gravel from the beds of rivers throughout the United States and deals directly with the methods employed and costs obtained by the Ohio River Sand Co. near Louisville, Ky. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance of J. R. Thoenen, mining engineer of the Bureau of Mines, in the collection of data and compilation of this report.

Jan 1, 1931