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By B. van Beek, J. H. Zietsman, A. Lexmond, N. J. Andrew

"In platinum group metals (PGMs) smelting, the slag-to-matte ratios are very high (approximately 4:1 to 9:1). The slag temperature therefore has a strong influence on matte temperature, which is a continual concern due to the low matte melting temperature and its resultant high superheat. Maintaining a stable slag temperature is therefore a critical safety and operational issue. This project aims to improve the understanding of the slag bath temperature drivers so that a more effective slag bath temperature control strategy can be implemented.With the aim of developing a multiphysics model of the furnace, extensive data analysis was performed to develop an in-depth understanding of the process before the start of modelling work. In this work, the effect of fluctuating furnace feed composition on slag temperature was examined. The results are based on equilibrium calculations using FactSage, implemented with ChemApp.A method was developed, using an equilibrium calculation at 25°C, to convert the available chemical assays to approximate mineralogical assays in order to determine the feed enthalpies. Actual 2013 furnace feed data was used and the average specific energy requirement to produce slag and matte at 1600°C was calculated to be 671 kWh/t concentrate. The furnace energy input was then kept constant, and it was found that the slag temperature varies significantly as a function of the feed composition. These results were compared to actual slag temperatures measured on site. It was found that close management of the furnace energy balance is important for maintaining a stable slag temperature."

Jan 1, 2014

By Frederick H. Raab

The electromagnetic retransmission system is a new, automated method of locating trapped mine workers. This technique overcomes many 1 imitations inherent in electromagnetic direction finding by reducing the effects of the conducting ground to an acceptable maximum, by finding position accurately in the presence of antenna tilt, and by eliminating the need for the receiver to be located directly above the subsurface transmitter. Three transportable three-axis magnetic-dipole transmitters on the surface create a system of electronic grids in which the phases of the downlink Signals convey position information. The subsurface retransmitter modulates the uplink carrier of the existing beacon transmitter with the received downlink signal; the coal-pillar loop antenna is used for both receiving and transmitting. The uplink receiver uses a three-axis antenna and extensive digital signal processing. A small computer integrates data, estimates position, and controls system operation through VHF-FM communications. Both coal-mine and deep-mine operation are possible by selecting appropriate transmitting power and signal frequencies. This report shows such systems to be both feasible and practical.

Jan 1, 1980

By N. C. Nissen, J. A. Thomas, A. Illis, K. N. Subramanian

Successful miniplant and laboratory testwork has indicated that high purity selenium can be produced from copper refinery slimes. The recovery technique fits into existing unit operations, and the selenium recovery in the new process was close to 99%. This recovery virtually eliminated any selenium being processed through the smelting stage. In addition, miniplant tests conducted at Inco Metals Co.'s J. Roy Gordon Research Laboratory in Mississauga, Ontario, have demonstrated the reliability of the process with respect to extractions, product quality, filtration characteristics, and effluent disposal. Inco's copper refinery at Copper Cliff, Ontario, produces about 500 t/d of copper with the anode slimes fall typically averaging 0.5% of the throughput. Investigations relating to the treatment of slimes within Inco's R&D have been conducted on several occasions since 1959, when the available alternatives such as acid or alkaline pressure leaching, aqueous or high temperature chlorination, roasting, smelting, etc., were considered. Interest in slimes processing was revived recently to meet increasingly stringent environmental standards and to replace equipment of a relatively old plant.

Jan 11, 1978

By George S. Rice, J. W. Paull, R. R. Sayers

"Standard rock dust for use in the rock dusting of coal mines might be defined tentatively as powdered mineral, light colored and free of carbonaceous matter and free silica, all of which will pass a 20-mesh screen while 50% of it will pass-through a 200-mesh screen.Such dust may be prepared from limestone, gypsum, anhydrite, or shale free of sand and flint. For the initial rock dusting of the average nongaseous bituminous mines enough standard rock dust should be applied so that the combustible content of the resulting mixture of rook dust with mine dust shall not exceed 45%, a range somewhere between 35% end 45% being the practical objective sought.All entries, slopes or passageways and room necks should be rock dusted.Additional safeguards are:a.,Rockdusting roomsb.,Scattering of dust in vicinity of shots before firing.c.,Placing of barriers in the mouths of panels, cross-entries and other key positions.Redusting becomes necessary whenever the combustible content of the mine dust exceeds the permissible maximum. This should be determined by regular, systematic sampling, followed by a simple analysis of the samples for combustible content. A Bureau of Mines volumeter for measuring the density can be used for the determination of combustible content."

May 1, 1924

By K. E. Stanfield

One of the initial projects under the oil-shale research and development phase of the Synthetic Liquid Fuels Act, Public- Law 290, 78th Congress, approved April 5, 1944, was a survey of oil shales of the United States for the selection of a site for an oil-shale demonstration plant. The oil shales were assayed by the conventional Bureau of Mines retort method proposed by Karrick and described by Guthrie in a more recent publication. From previous experience and that had in making these assays, it became evident that the assay method should be modified or replaced by a more satisfactory one. There are several outstanding objections to the Bureau of Mines oil-shale assay method: (1) the oil yields are frequently smaller than those obtained by other types of assay equipment and by commercial retorts; (2) the assayed oil yield represents only a portion of the organic matter in the shale, which under more favorable conditions, may, Jae converted, more completely into oil; (3) the retorting procedure is controlled mainly by trial-and-error methods; and (4) the assay requires approximately 6 hours for completion.

Jan 1, 1949

By Paul Madsen, Bade Sozer, Thomas Hennings, Eileen Test

The Rondout Bypass Tunnel in New York has two access shafts. The upper sections of the shafts are lined with steel pipe to resist a substantial net internal water head . Initial design included a ¾-inch-thick cement mortar lining (CML) for all three components. Because of concerns with CML application on large-diameter pipes, the protective lining was redesigned for shotcrete application. This paper discusses the details of that design, mock-ups, and shotcrete application.

Jun 13, 2023

By Juan J. Monsalve, Nino Ripepi, Richard Bishop, Jon Baggett

"Terrestrial laser scanning (TLS) is a useful technology for rock mass characterization. A laser scanner produces a massive point cloud of a scanned area, such as an exposed rock surface in an underground tunnel, with millimeter precision. The density of the point cloud depends on several parameters from both the TLS operational conditions and the specifications of the project, such as the resolution and the quality of the laser scan, the section of the tunnel, the distance between scanning stations, and the purpose of the scans. One purpose of the scan can be to characterize the rock mass and statistically analyze the discontinuities that compose it for further discontinuous modeling. In these instances, additional data processing and a detailed analysis should be performed on the point cloud to extract the parameters to define a discrete fracture network (DFN) for each discontinuity set. I-Site Studio is a point cloud processing software that allows users to edit and process laser scans. This software contains a set of geotechnical analysis tools that assist engineers during the structural mapping process, allowing for greater and more representative data regarding the structural information of the rock mass, which may be used for generating DFNs. This paper presents the procedures used during a laser scan for characterizing discontinuities in an underground limestone mine and the results of the scan as applied to the generation of DFNs for further discontinuous modeling.INTRODUCTIONAccording to the Mine Health and Safety Administration (MSHA), between 2006 and 2016, the underground stone mining industry had the highest fatality rate in 4 out of 10 years, compared to any other kind of mining (MSHA, 2016). Additionally, during that same time, 40% of the fatalities were due to ground control issues, such as roof and rib collapses and pillar bursts. The National Institute for Occupational Safety and Health (NIOSH) developed guidelines for designing underground stone mines (Esterhuizen, Dolinar, Ellenberger, and Prosser, 2011). However, these guidelines do not apply to all underground stone mines.Monsalve, Baggett, Bishop, and Ripepi (2018) present a case study of an underground limestone mine experiencing a structurally controlled mode of failure. The authors analyze different methods to study that type of instability. They conclude that the integration of terrestrial laser scanning (TLS) with discrete element modelling (DEM) can be used to prevent rock falls in underground excavations to enhance worker safety. However, an adequate rock mass characterization and structural mapping must be performed in order to generate reliable models that allow the engineer to have a better understanding of the rock mass behavior."

Jan 1, 2018

By Eugen Gluck, Gus Van Weert, Peter Kondos

"Microwaves have the capability to heat up sulphides, especially clusters of particles of approx. 1 mm. Some sulphides absorb microwaves more readily than others. Molybdenite is especially effective in this regard, possibly due to its flaky nature and/or electrical conductivity. Even where it occurs in low concentrations in a deposit, individual rocks may be ore grade due to the high monetary value of MoS2. Such rocks often result from crushing mined veinlets or stockwork, or are contained in the cutoff grade fraction of ROM. Machine segregation of rocks high in MoS2 by infrared sensors after microwaving could therefore advantageously be used to upgrade lower grade ore between Mine and Mill. This would reduce the size of the latter, and thus its CAPEX and OPEX. Such upgrading could also yield shipping ore for a distant Mill, or extend ore reserves.Barrick Gold Corp. has been supporting the development of MW/IR sulphide sorting for the past three years. The results of MW/IR sorting work on molybdenite and other (pyritic) ore samples from a variety of sources are being presented here.INTRODUCTIONThis paper looks at mechanized, i.e. machine ore sorting technologies currently available and under development, and what conditions would be needed for the potential application of such ore sorting to sulphide mining and milling. Current machine sorting involves no-contact sensing technology for rocks, and signal processing after sensing to activate airblast segregation of certain rocks, normally the smallest mass to keep compressed air costs down.The forerunner of modern sorting is probably magnetic separation, which utilizes an inherent property of certain ores to divert it into mag and non-mags fractions. Radiometric ore sorters, which have been applied successfully for decades in the pre-concentration of uranium ores (Wotruba and Riedel, 2006) initiated modern sorting. In the 90’s, sensor-based machine sorting became a viable means of increasing the overall economic recovery of a resource. This technology became driven by the availability of low cost computing equipment and the concurrent development of algorithms, and by the availability of extremely fast response sensors and air actuators, allowing the sorting equipment to run faster, dropping the cost per tonne. It has been in industrial minerals processing that rock sorting has been most widely adopted, not really surprising. Liberation occurs on a different scale than in the base metal industry. Most industrial minerals are mined from massive deposits, requiring (in the past) no upgrading. Many of these operations now run into product contamination problems, which ore sorting can solve. One illustration: in Finland, a quarry is separating limestone from dolomite at 500 tonnes / hour, with individual rocks weighing up to 15 kg. Many of these industrial minerals operations have stockpiles of earlier discarded below-quality rocks, now being reprocessed with the help of ore sorting. The economics of this are very favourable, going from zero or negative value (stockpiles can not be left when closing the mine) to full product value for at least a portion of the stockpile. This suggests that in the future the economics of overburden sorting could become attractive under the right circumstances and such treatment could well become an integral part of open pit mine development."

Jan 1, 2009

By John Heilig, Patrick Andrieux

"Near-field monitoring of blast induced seismic vibrations is a practical and useful way of assessing blast field behaviour for diagnosis and optimization purposes. It is also necessary in order to provide the information from which empirical vibration prediction equations, such as the one proposed by Holmberg (11 for example, can be derived. (Strictly speaking, the “near field” extends from the blasthole itself to about one charge length away from it; however, throughout this article, “near field”will.most often refer to the outer limit of this zone, from roughly 0.75 to 1.50 charge length away.) In order to obtain reliable data, proper field monitoring techniques are of paramount importance. Once the data are properly recorded, analysis can be done either in the time domain (describing vibration amplitude vs. time) or in the frequency domain (usually describing vibration amplitude vs. frequency)."

Jan 1, 1995

By Douglas J. Harvey

The surface tension of lead-tellurium alloys (in the range 0 to 6.70 at. pct Te) ad lead-arsenic alloys (in the range 0 to 10.53 at. pct As) has been examined by the maximum bubble pressure method. The surface tension of high purity lead can be expressed over a range of temperatures (M.P. to 750°C) by the relationship = 512 — 0.133t. Arsenic and lellurium were both found to be surface active in lead. The surface excess concentration at 700°C was .found to be constant at 0.74 x 10-10 moles per sq cm for tellurium. The surface excess of arsenic at 700°C varied between 0.26 x 10-10 moles per sq cm at 0.16 at. pct to 1.5 x 10-10 moles per sq cm at 8.3 at. pet. The surface tension of lead has been investigated sporadically over the last 90 years. The first recorded study was made by Quincke1 who used a rather crude application of the drop-weight method. Hogness2 obtained the first reliable value for the surface tension of lead by measuring the pressure necessary to force the liquid metal from the end of a small capillary of known radius. Hogness gives the empirical formula: ?(surface tension)= 444 - 0.077 (l-327) which describes the relationship between surface tension and temperature ("C); This work was followed by that of Bircumshaw3 who applied the two-capillar maximum bubble pressure method of Sugden.4 The values published by Bircumshaw are in good agreement with those found by Hogness. Matuyama5 examined the surface tension of lead by the drop weight method. However, the values found are somewhat higher than those previously reported. More recent investigations by Greenaway6 and by Melford and oar' have resulted in data which are not in close agreement, but which are well within the expected range at most temperature levels. The study of the surface tension of lead alloys began with Drath and sauerwald8 who examined the lead-bismuth system. They found that the surface tension values of the alloys in this system deviated only slightly from the ideal mixture rule. Matuyarna5 examined the lead-antimony system. Bircumshaw the lead-tin, and the lead-indium system was studied by Hoar and Me1ford.10 The results of these investi- gations are summarized in Fig. 1. It may be seen that the data vary only slightly from the ideal mixture rule. As none of the metals studied and reported in the literature has a very interesting effect on the surface tension of lead,*the next logical step might be to examine the effect of metals of low solubility or nonmetals having some liquid solubility. Baes, and Kellogg11 have pointed out that the elements most likely to be surface active in liquid metals are ones of limited solubility in the liquid state and possessing weak intermolecular bonding forces in the solid state. Therefore, Group V, VI and VII nonmetals are most likely to be surface active. It was decided to examine the effect of a borderline metal, arsenic, and a nonmetal tellurium. Arsenic forms a eutectic with lead having a melting point of 290°C and a composition of 6.9 at. pct As.13 Pure arsenic sublimes when heated above 610°C. Even though alloying with lead lowers the vapor pressure, fumes containing arsenic are evolved at a very noticeable rate when lead-arsenic alloys are heated above 650°C. Tellurium raises the liquidus temperature of lead sharply to 904°C,14 the melting point of PbTe (lead-telluride). The solid solubility of tellurium in lead was determined by Greenwood and worner15 to be 0.0007 at. pct at room temperature. EXPERIMENTAL METHOD Surface Tension Measurement—The two capillary maximum bubble pressure method for measuring surface tension developed by Sugden,4 and used later

Jan 1, 1962

By D. H. Desy

The Bureau of Mines studied the properties of copper that had been oxide dispersion-strengthened with 2 vol pct of either yttria or alumina. Compounds of copper and aluminum or yttrium, coprecipitated from aqueous solution, were converted to oxides; the copper was reduced, compacted, sintered, and extruded. For the resulting copper-dispersoid composites, room temperature tensile properties after annealing in hydrogen, elevated temperature tensile and stress-rupture properties, and electrical conductivity were determined. Compared with oxygen-free copper, copper-2 vol pct alumina or yttria had improved strength after annealing between 400° and 1,000° C, and improved elevated temperature strength, with little loss in electrical conductivity.

Jan 1, 1969

By D. R. Hanson

The acoustic vibrational spectra of impacted rock slabs were examined at the Denver Research Center, US Bureau of Mines, in an attempt to characterize the behavior of partially detached mine roof rocks. The ultimate goal of this study was to develop a technique or instrument that could provide a quick, accurate, quantifiable measure of mine roof stability. The power spectra of unstable rock slabs were found to contain more energy in the range of 200 to 1000 Hz than solid rock. Comparison of the power contained between 500 and 1000 Hz with that between 3000 and 3500 Hz provided a quantitative measure of rock stability. A lightweight prototype field instrument was designed, constructed, and field tested. This battery-powered instrument computes the power contained in the two frequency bands, compares their magnitude, and displays a number related to the stability of the block tested. Field tests showed the instrument provided reliable measurements of block stability even under conditions of noise that would have seriously degraded the accuracy of the standard methods of roof sounding.

Jan 1, 1986

The use of pipeline-c to carry crude'oil and petroleum pro-ducts is a reliable and economic*Way to transport large quantities of oil. The length and size of these pipelines have continued to grow throughout the world as the demand for petroleum has in-creased and as the price of other transportation-methods has risen. At the present time pipelines 'can move a barrel of oil a distance of 100 miles at an average cost of ,80.06 U.S. dollars.The major elements in pipeline design are discussed. Methods of calculating pressure drop and horsepower requirements are pre-sented. These are variations of standard equations.in which the elements of each equation are expressed in terms common to the petroleum industry. Major equipment is discussed., particularlyas it relates to operation and economics.Cost data are presented to aid in preliminary economic ana-lysis. Curves illustrate the cost of oil transportation at flow rates between 10,000 and 500,000 barrels per day and permit the selection of pipe diameter-which will result in minimum operating costs.

Jan 1, 1962

By Catharine T. Fogg

The Bureau of Mines investigated the availability of flake and high-crystalline natural graphite from 4 domestic and 25 foreign mines and deposits in 11 market economy countries (MEC's). Demonstrated resources were estimated to be 95 million metric tons (Mmt) containing 5.61 Mmt of recoverable flake and high-crystalline graphite products. Fifty-five percent (3.17 Mmt) of the total recovered product is estimated to comprise plus 100-mesh (150-µm) flake pro-ducts and "lump" and "chip" high-crystalline products, designated as "graphite A" in this study; 45 pct (2.44 Mmt) of the total is minus 100-mesh (150-µm) flake products and "dust" high-crystalline products, designated as "graphite B." Total production costs, including all costs needed over the life of each operation, were determined at a 0-and 15-pct discounted-cash-flow rate of return (DCFROR) for both graphite A and graphite B products. For a 15-pct DCFROR, 1.74 Mmt (54.9 pct) of the graphite A products is available at $600/mt or less and 2.13 Mmt (67.2 pct) is available for $800/mt or less. For the same DCFROR, 1.08 Mmt (44.3 pct) of the graphite B is available at $200/mt or less, and 1.71 Mmt (70 pct) is available at $325/mt or less. No domestic resources were determined to be economic at present prices. A sensitivity analysis of the relative economics of the Alabama graphite deposits under various operational parameters is presented in an appendix. All evaluations are in January 1984 dollars.

Jan 1, 1987

By D. O. Hamiltion

The ISMS program provided for the development and demonstration of equipment modifications in both conventional and continuous coal mining systems. This report describes activities during the demonstration of the conventional equipment and includes machine performance, results of data gathering, system evaluation, and recommendations for implementing improvements.

Jan 1, 1976

By Bengt T. Andersson

Outokumpu Consulting Engineers, Outokumpu Oy SF-02200 Espoo 20, Finland This paper describes experiences from some operating non-ferrous flash -smelters and focuses on the advances in smelter byproduct and gas treatment engineering design. In this context a summary is given of the specific technical and economic benefits achieved-by flash -smelting technology and oxygen enrichment. The paper will also briefly outline a few new process and equipment developments.

Jan 1, 1983

By E. S. Geskin

"This paper is concerned with the construction of a formal technique for the selection of a metallurgical technology. Exergy consumption is used as the criterion of process efficiency. Different items of the exergy balance are considered and techniques for the reduction of exergy consumption are determined. The selected techniques of exergy saving enable us to identify processes which should be used at different stages of steelmaking. The combination of the selected processes enables us to suggest a technology for conversion of iron ore into steel products. The selection of this technology narrows the range of further search of metallurgical processes. The paper shows that qualitative thermodynamic analysis can be used as the first step in the design of metallurgical processes. IntroductionThe existing processes for making, shaping and treating of steel enable us to convert the available iron bearing ores into marketable steel products. However, the energy cost of metal production is much higher than thermodynamically required, while the metal properties are much lower than thermodynamically available. Increasing cost and declining availability of energy and raw meterials make the creation of new steelmaking technologies imperative. In recent years, the number of novel processes for the making, refining, and shaping of steel have been suggested and tested. Some found a practical application. However, the tested technologies make up a small portion of the physically available routes for the conversion of iron ore into a marketable product. It is also not evident that the optimal routes have been tested and that the selected technologies are the best among those tested.Although the development of new metallurgical technologies must be based on the experimental and practical information, the number of the alternative routes for the making, shaping and treating of steel, as well as the cost of examining each single route, make necessary the use of analytical techniques for the evaluation of the possible ways of process development."

Jan 1, 1988

By D. B. Myers

The consistent upward trend in crude oil production prevailing in California throughout the greater part of 1929, was effectively checked in November by a curtailment program instituted by mutual agreement between operators in four of the major fields. This program artificially reduced daily production to approximately the same daily figure as prevailed in December, 1928. The large amount of deep drilling during the later part of 1928 and during 1929 has established a potential, however, which is far in excess of refinery needs in the state. Low prices for crude oil which prevailed in California during 1928 continued during 1929. General curtailment continued in the older fields in San Joaquin Valley. The number of wildcat and exploratory wells drilled throughout California was materially increased, but no major field was discovered unless the recent bringing in of the Ohio Oil Co.'s Recreation Gun Club No. 1 well, near Venice in Los Angeles Basin, during the closing days of 1929 results in such a field. Significant developments during 1929 were: (1) The discovery of three deeper zones in the Santa Fe Springs field known as the O'Connell, Clarke, and Hathaway; (2) Kettleman Hills development and unanimous agreement to restrict production; (3) developments along the Santa Barbara Coast and the drilling of tideland permits; (4) extensions of some of the older producing areas in the San Joaquin Valley; (5) the Lawndale and Santa Barbara Mesa structures, the former discovered in Los Angeles Basin in 1928, the latter in Santa Barbara County in 1929, proved to be failures; (6) intensive exploration throughout the state and the drilling of a large number of deep wildcat wells; (7) discovery of oil by the Ohio Oil Co. in the Los Angeles Basin at Venice; (8) Long Beach and Ventura Avenue fields maintained steady production throughout the year. As a natural sequence to the discovery of high-gravity oil fields in Kettleman Hills and at Elwood in 1928, a tremendous amount of exploratory work was done in 1929 in areas underlain by rocks of lower Miocene age, particularly along the Santa Barbara Coast area, the San Joaquin Valley, and the Salinas Valley, where the Vaqueros and Temblor sands were considered to hold possibilities for production.

Jan 1, 1930

By Elmer W. Pehrson

Minerals have played a prominent role in the affairs of man and nations since time immemorial but with the advent of the industrial revolution, expanding use of the products of the mineral kingdom became synonymous with the material progress of mankind. Individuals and business groups have recognized this fact so have been aggressive in searching for and utilizing mineral resources, with notable success. Indeed, their achievements are primarily responsible for the present Machine Age. On the other hand, until recently the body politic has failed to grasp fully the essentiality of minerals although, at times, access to mineral supplies has been an important factor in the political maneuvers of nations. This chapter is concerned primarily with the broader political and economic relationships of mineral resources to the world economy, and with the internal and external actions of nations in the field of minerals. Many factors that condition the mineral economy of regions and the world as a whole, influence the internal and external affairs of individual nations. The more important of these are: 1. The nature of man's dependence on minerals. 2. The problems resulting from the unique characteristics of mineral occurrence. 3. Geopolitical concepts. 4. Minerals and world power. Actions of individual nations affecting their mineral economy seek two basic objectives: 1. Attainment and maintenance of prosperity. 2. Military security. Other objectives may be cited but on careful analysis they become integral parts or extreme phases of the two points noted above. For example, the twentieth century aggressions of the USSR, Germany, Italy, and Japan might be considered as direct bids for world power but they also can be interpreted as exaggerated or mistaken efforts toward military security and peacetime prosperity. Similarly, trade barriers, nationalization of industries, foreign exchange manipulations, taxation, monopolistic prac-

Jan 1, 1964

By Joseph J. Wallace

1. From the standpoint of known recoverable reserves, the following is the order of importance of the beds: Upper Kittaoning, Lower Kittanning, Upper Freeport, Lower Freeport, Middle Kittaning, Clarion, Pittsburgh, and Redstone. 2. mown measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and on 1,800 tons per acre-foot of coal in place, me estimated at 1,859 million short tons as of January 1, 1952. Of this, 1,351 million short tons me in beds 28 inches and more thick. Areas in each bed were omitted from the estimates because available data relative to the bed characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1953