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The Heavy Media Separation plant operated at Lidsdale siding, eight miles from Lithgow, by the N.S.W. Mining Co. is a product of the Western Machinery Company, of D.S.A.This mill, designed to use finely ground magnetite as the heavy medium, was prefabricated in America and shipped to Australia for erection.First operated early in December, 1951 it has worked on a two-shift basis since. Designed for an input rate of 330 tons per hour, this mill is capable of washing 4 in. x /u in. coal down to its inherent ash by removing all heavy material, including high-ash coal.The principle is quite simple. A stream of raw coal is fed into the separatory vessel which contains a liquid medium, the density of which is adjusted to produce the desired split between coal and refuse. In this bath the lightest coal floats, and all material heavier than the specific gravity of the medium sinks, and is removed separately. Such a system is,. ideally suited to Western coal, as there is no definite splitting point between coal and refuse. Inherent ash of the coal fed to the plant ranges from 8 to 25%, the corresponding density range being from 1.28 up to 1.8.Generally speaking, the higher the density the higher the ash content of the coal.The density in the separatory vessel (hereafter called the cone) can be quickly and easily adjusted throughout the above range to any desired value. Customer requirements, coupled with the economics of washing, dictate the proper specific gravity to be maintained. At present this is held at 1.52...

Jan 1, 1954

By ALBERT E. HALL, Arno C. Fieldner, Alexander L. Field

As a safeguard against excessive clinker troubles, specifications for the purchase of coal can be drawn to include the "softening" or "fusing" temperature of the ash. The value of such information has been recognized by the Bureau of Mines and has induced the bureau to investigab~ laboratory methods of determining the fUSIbility of coal ash, and the bearing of the results on clinker formation in fuel beds. The bureau realized that the fusibility of a mixture of oxides and silicates snch as is comprised in coal ash ,'aries according to the conditions under which tests are made, and that in the absence of any generally accepted method, no agreement is to be expected among tests made in differ«:-nt laboratories. Indeed, Marks a has recently called attention to differences as great as 3900 C. that were obtained with the same sample of ash by two different laboratories. Therefore if a fusion-temperature clause is to have any place in specifications for coal, a standard m('thod of t('sting should be adopted in order to insure comparable results by different laboratories and to obtain the softening or fusing temperature of the ash unde:'r conditions similar to those of a fuel bed. After a consistent method has been devised for obtaining comparable:' results at different laboratories, there will remain the correlation of these results with those from the burning of coal in furnaces before the value of fusibility tests in coal specifications can hE' finally determined.

Jan 1, 1918

By D. Harrington

The greatly extended use of the underground trolley-locomotive system for hauling coal without doubt was one of the most important factors in the rapid progress of coal mining and the increased production of coal in American coal mines during the period 1910-20. Much of the superior efficiency of production of our underground coal and metal lines should also be credited to the trolley locomotive system. The trend to mechanization of mines during the past 15 years, mere particularly the past 5 years, with higher production per man employed and greatly accelerated advancement of working places, has required increased use of trolley locomotives, necessitating larger equipment, higher speeds, and more 'frequent turn over of pit cars. This is re¬flected in increased size of locomotives and the use of larger mine ears (some with a capacity up to or over 10 tons); moreover, heavier rails and larger-size trolley wires have boon or ought to have boon installed. Trolley-locomotive haulage has proved to be rapid; economical, efficient, and productive; nevertheless; in spite of these advantages, so-many hazardous features and, unsafe conditions are involved and the price paid in life and property is so high as to justify the statement that the system should be scrapped if it cannot be operated under reasonably safe conditions. Since bare trolloy wires were introduced into underground mines, they have boon responsible for the death of hundreds of diners, property damage totaling millions of dollars, an indeterminate loss of tonnage through the abandonment of mines or parts of mines, and loss of time after disasters caused by fires or explosions originated by the trolley haulage system.

Jan 1, 1945

By Bhaskar B. Thapa

The proposed Caldecott fourth bore will consist of a two lane highway tunnel along California State Route 24 near the City of Oakland. The proposed design and construction sequence for the 15-m-diameter tunnel are based on the New Austrian Tunneling Method (NATM). The initial support system incorporates combinations of shotcrete, rock dowels, lattice girders, spiles, and grouted steel pipe canopies. The final lining is cast-in-place reinforced concrete. A waterproofing membrane and drainage system are placed between the initial and final linings. State Route 24 is a lifeline route, required to be open to emergency vehicles within 72 hours after a major earthquake, defined as having a return period of 1,500 years and a peak ground acceleration of 1.2 g. Although the seismic design criteria are stringent, the design of the tunnel lining system is ultimately controlled by static ground loads in the weak rock along the alignment.

Jan 1, 2008

1. Domestic Production and Use: In 1984, 12 companies operated 27 primary aluminum reduction plants, with 3 firms accounting for 57% of production. Washington, Oregon, and Montana accounted for 35% of the production; Indiana, Kentucky, Missouri, and Tennessee 25%; Alabama, Arkansas, Texas, South Carolina, and North Carolina 20%; other States 20%. Based on published producer prices, output of primary metal in 1984 was valued at $7.2 billion. Aluminum consumption by 25,000 firms was centered in the east-central United States. Packaging accounted for an estimated 35% of domestic consumption in 1984, transportation, 20%; building, 18%; electrical, 9%; consumer durables, 8%; and other uses, 10%.

Jan 1, 1985

By Eduardo Pimenta de Melo, Rambabu Pothina, Rajive Ganguli

Sensors are everywhere in the mining industry, with sensor information being used to monitor and operate processes. Therefore, when sensor information is wrong, economic losses can occur. Unfortunately, sensor errors are usually not detected till they become large. This is problematic as most calibrate their sensors no more than once a year (Beamex, n.d.). Using principles of data mining, where all relevant information is tapped to glean hidden information, Pothina [8] designed an algorithm to detect errors in temperature sensors in gold stripping circuit in Pogo mine, Alaska. This paper continued his work by analyzing the behavior of the algorithm on baseline data and testing the algorithm in new data and under more rigorous conditions. It also made a change to the algorithm. The modified algorithm performed very well in the new data. It also worked well under the new error conditions. Three types of errors were seeded, a fixed additive error (+ 2%), a fixed subtractive error (− 2%), and a noisy, normally distributed error, with a mean value of + 2%. Artificially seeded errors were detected within about 20 gold stripping cycles. Inherent bias in operation impacted algorithm performance by increasing the number of cycles needed to detect errors. This paper reinforced Pothina’s [8] conclusion that when data mining approach is used, sensor errors can be detected even when they are pretty low. Significant economic losses can thus be minimized.

By L. Andrews

Mineralogy, traditionally associated with concentrator studies, is being increasingly applied to problems in pyrometallurgy. Such investigations commonly make use of a number of techniques, and the results are combined for a meaningful interpretation, which can lead to a successful solution for the problem. Mineralogical techniques are described for various pyrometallurgical operations. Examples are given of studies and investigations involving mineralogy in chemical-looping combustion, feed monitoring to platinum-smelting furnaces, and losses to slag in base metal and platinum smelting.

Jan 1, 2011

The optimum cut-off grade policy maximizes the net present value (NPV) of an open pit mining operation subject to the mining, processing, and refining capacity constraints. The traditional approaches to cut-off grade determination ignore the escalation of the economic parameters such as metal price and operating costs during life of an operation, and consequently lead to unrealistically higher values of the objective function. Further, the NPV of a mining operation declines due to the depletion of the available reserves, causing a decline in the optimum cut-off grade, i.e. higher cut-off grades in the early years of an operation and lower cut-off grades during the later years. Hence, low grade material mined in the earlier years may be stockpiled for processing during later years to offset the effect of escalating economic parameters on NPV. This paper demonstrates the combined impact of introducing economic parameters, escalation and stockpiling options into the cut-off grade optimization model. The model promises an enhancement in NPV as illustrated in a case study incorporating practical aspects of an open pit mining operation.

Jan 1, 2011

By C. B. Manula

This report is mainly concerned with the modification and development of a users manual for the Open-Pit Materials Handling Simulator (OPMHS) developed at Penn State. Model Modifications included the introduction of a free-format input, the application of a Weibull random generator, facilities to stochastically simulate shovel-dragline operations, and routines to increase the flexibility in making truck assignments. At the same time, core storage requirements and execution times were minimized and all P.S.U. conventions were removed to allow operation on other computing systems.

Jan 1, 1976

This volume constitutes the Survival Subsystem portion of the final report for the Coal Mine Rescue and Survival System (CMR&SS) program, which was conducted by the Westinghouse Electric Corporation under contract to the United States Bureau of Mines (Contract Number H0101262 dated June 17, 1970). The program was directed by the Special Systems Department of the Westinghouse Baltimore, Maryland, facility. The basic objectives of the CMR&SS program were to develop and test hardware to determine the efficacy of a variety of coal mine rescue and survival concepts and techniques. These concepts were drawn from two major sources: the Request for Proposal from the Bureau of Mines1 and the final report on the Mine Rescue and Survival Study conducted by the National Academy of Engineering2 (NAE).

Jan 1, 1971

By Will B. Jamison

An ignition detection and suppression system was developed under the scope of this contract. The objective of this machine mounted system was to detect flames caused by frictional sparking from the cutting bits of a continuous mining machine and to suppress it with sufficient speed to prevent the development of an explosion, and to keep the flame from harming the machine operator.

Jan 1, 1976

By R. J. Anderson, A. V. Castelli

In 1986, United States' barite production fell 48.9%, consumption - sold or used by grinding plants - was off 47.3%, and imports were down 63.8%. Meanwhile, world mine production decreased 29.6%, according to the US Bureau of Mines. However, value of US-produced barite FOB mine increased 46.51%, according to USBM figures. The declared value CIF US port of all imported unground barite decreased from $41.94/t ($46.23 per st) to $39.02/t ($43.01 per st). Nevada continued to be the leading US producer of barite with 69% of the total. It is followed by Georgia, Missouri, Tennessee, and California. The USBM estimates that 65% of the barite mined was used as a weighting agent in drilling fluids. The remaining 35% was used in the production of barium chemicals and as a filler. Most of the production from Missouri, Georgia, and Tennessee was used in the non-oilfield sector. This sector made up a larger percentage of the US produced barite in 1987 than it did in 1986, increasing the overall value per ton of barite. Barite consumption was at its lowest since 1963. It is estimated that 80% of the barite was consumed in the drilling fluid market. The remaining 20% was used in barium chemicals, glass, and as filler in plastics and paper. The decline of barite used in drilling fluid followed the decline in the average number rotary rigs operating - 964 versus 1968 in 1985. This was the lowest average number of rotary rigs operating since 1971. The non-oilfield market was up 5.3% in 1986. This increase can be attributed to the increased use as a filler in plastics. Imports of crude barite, though down nearly two-thirds, still made up 65% of the barite consumed in the US. China was the leading exporter to the US with 58%, followed by India, 15.4%; Morocco, 11%; Thailand, 5.4%; Mexico, 4.6%; Chile, 3.9%; and Ireland, 1.7%. Less than 1% of the imported ore was used in the nonoilfield sector. Imports of ground barite dropped from 64.4 kt (71,000 st) to 19.8 kt (21,800 st) in 1986. Of this amount, 14.1 kt (15,500 st) were used in drilling fluids in 1986 and the remainder for non-oilfield use. During 1986, more of the grinding plants supplying the drilling fluid market were closed. Dresser Magcobar and IMCO Services, a Halliburton company, formed M-I Drilling Fluids Co. Mine production in the US will probably decrease in 1987 due to the lower cost of imported ore. No significant change is expected in the drilling fluid market. The average number of operating rotary rigs is estimated at 950 in 1987 versus 965 in 1986. The nondrilling fluid markets (chemicals, glass, and filler) will follow the overall US economy. Bauxite and alumina R. J. Anderson, Ohio State University US bauxite production in 1986 dropped to a pre-World War II level, continuing a decline that began a decade ago. 1986 production totaled 450 kt (496,000 st), compared to 674 kt (743,000 st) in 1985. World production of bauxite also decreased in 1986. This reflected the soft market in alumina, aluminum, and related products. Total mine production worldwide came to 79 Mt (87 million st), down from 85 Mt (94 million st) in 1985. For the sixteenth consecutive year, Australian production of bauxite led all other sources. No other country approached the 28 Mt (31 million st) mined in Australia in 1986, despite a 4.4-Mt (4.9-million st) drop in its output from 1985. Other major producers in 1986 were: Guinea 11 Mt (12 million st), Brazil, 6.5 Mt (7 million st), Jamaica, 6.5 Mt (7 million st), and Suriname 2.8 Mt (3 million st). Despite weakness in world demand for bauxite, Venezuela, heretofore an alumina producer, is now pushing development of a new mining venture near the western border of the state of Bolivar. Plans call for barging bauxite down the Orinoco River to the Ciudad Guyana alumina plant, a distance of 650 km (400 miles).

Jan 5, 1987

By John Marsden, Mike Botz

A variety of modeling techniques can be utilized to forecast metal production at heap leaching operations. These approaches reflect a wide range of complexity, flexibility, time to implement, cost, and accuracy. For many operators, a spreadsheet-based modeling technique is attractive since the calculations are directly accessible, models can often be developed by site staff, and the results are generally easy to extract and interpret. The authors have developed a spreadsheet-based modeling technique that provides a high degree of flexibility, while still considering detailed operating information for ore properties, leach kinetics, scaleup factors, lift height, and in-heap metal inventories. The technique involves establishing kinetic leach curves for each ore type to characterize metal extractions, followed by application of separate metal recovery curves to define the rate at which leached metals exit the heap in pregnant solution, taking into account delays due to the in-heap solution inventory. At any point in time, the difference between total metal extracted and total metal recovered is equal to the in-heap inventory of the leached metal. This modeling technique is particularly useful for larger multi-lift heaps where delays in metal recovery are appreciable due to in-heap solution holdup. The technique is also applicable to sites with multiple heaps, leach cycles, and/or metal recovery plants (e.g., carbon columns for gold; solvent extraction for copper). This paper describes the modeling technique, including input data required and methods for defining kinetic leach curves and metal recovery curves. The technique is compared against an alternative spreadsheet technique using a simplified in-heap solution inventory calculation to forecast metal production, which has proven to be effective at a number of sites.

By John Marsden, Mike Botz

A variety of modeling techniques can be utilized to forecast metal production at heap leaching operations. These approaches reflect a wide range of complexity, flexibility, time to implement, cost, and accuracy. For many operators, a spreadsheet-based modeling technique is attractive since the calculations are directly accessible, models can often be developed by site staff, and the results are generally easy to extract and interpret. The authors have developed a spreadsheet-based modeling technique that provides a high degree of flexibility, while still considering detailed operating information for ore properties, leach kinetics, scaleup factors, lift height, and in-heap metal inventories. The technique involves establishing kinetic leach curves for each ore type to characterize metal extractions, followed by application of separate metal recovery curves to define the rate at which leached metals exit the heap in pregnant solution, taking into account delays due to the in-heap solution inventory. At any point in time, the difference between total metal extracted and total metal recovered is equal to the in-heap inventory of the leached metal. This modeling technique is particularly useful for larger multi-lift heaps where delays in metal recovery are appreciable due to in-heap solution holdup. The technique is also applicable to sites with multiple heaps, leach cycles, and/or metal recovery plants (e.g., carbon columns for gold; solvent extraction for copper). This paper describes the modeling technique, including input data required and methods for defining kinetic leach curves and metal recovery curves. The technique is compared against an alternative spreadsheet technique using a simplified in-heap solution inventory calculation to forecast metal production, which has proven to be effective at a number of sites.

By John Marsden, Mike Botz

A variety of modeling techniques can be utilized to forecast metal production at heap leaching operations. These approaches reflect a wide range of complexity, flexibility, time to implement, cost, and accuracy. For many operators, a spreadsheet-based modeling technique is attractive since the calculations are directly accessible, models can often be developed by site staff, and the results are generally easy to extract and interpret. The authors have developed a spreadsheet-based modeling technique that provides a high degree of flexibility, while still considering detailed operating information for ore properties, leach kinetics, scaleup factors, lift height, and in-heap metal inventories. The technique involves establishing kinetic leach curves for each ore type to characterize metal extractions, followed by application of separate metal recovery curves to define the rate at which leached metals exit the heap in pregnant solution, taking into account delays due to the in-heap solution inventory. At any point in time, the difference between total metal extracted and total metal recovered is equal to the in-heap inventory of the leached metal. This modeling technique is particularly useful for larger multi-lift heaps where delays in metal recovery are appreciable due to in-heap solution holdup. The technique is also applicable to sites with multiple heaps, leach cycles, and/or metal recovery plants (e.g., carbon columns for gold; solvent extraction for copper). This paper describes the modeling technique, including input data required and methods for defining kinetic leach curves and metal recovery curves. The technique is compared against an alternative spreadsheet technique using a simplified in-heap solution inventory calculation to forecast metal production, which has proven to be effective at a number of sites.

Sep 3, 2019

By A. D. Pienaar

The aqueous chemistry of niobium and tantalum compounds with hydrofluoric acid is a mature field of investigation. In contrast, very little attention has been paid to reactions of these compounds in non-aqueous environments. Similarly, reactions of elemental fluorine with niobium and tantalum compounds have received little more than cursory attention in literature. This work discusses the isothermal reaction kinetics derived from thermogravimetry, using a less redundant approach than is currently the standard. We also discuss the most likely kinetic models for this reaction.

Jan 1, 2012

By Chas. F. Jackson

During the past 5 years the Bureau of Mines has published information circulars dealing with mining methods and costs at 78 ore mines; 7 circulars, each of which is devoted to a discussion of one of the principal mining, methods; and 23 circulars dealing with special phases of mining, such as ventilation, shaft sinking, tunnel driving, the cost of equipping and developing prospects and small mines, underground transportation, diamond drilling, and ground support. These circulars were written by many different authors, and in order that the method of presentation and the basis for compilation of data might be the same in all the papers the Bureau drafted an outline to be followed in their preparation. To clarify the data in these circulars, which are in the libraries of many engineers and mining companies, and the summarized data presented in this paper, that portion of the outline dealing with cost and labor-performance data is reproduced below.

Jan 1, 1934

By N. Gatelier, T. You, J. C. Kandel

ABSTRACT: Underground hydrocarbons storage is a very specific domain for the designer. He is usually free to adjust the section, shape and layout to cope with the geological and geotechnical conditions. This paper presents a panorama of the geotechnical design of mined underground storage caverns, then lists a number of uncommon features encountered in a storage excavated in Sydney, Australia, the Elgas LPG project that had to face major non-isotropic conditions with numerous local variations, impacting on the achievement of the design profiles. Changes in geotechnical design methodology and practice are examined through this project, now in operation, which will have lasted altogether almost ten years. KEY WORDS: underground storage, geotechnical engineering, stability, methodology, design. ZUSAMMENFASSUNG: Die untertaegige Speicherung von Kohlenwasserstoffen unterliegt in der Planung sehr spezifischen Bedingungen. Der planende Ingenieur hat bei der Dimensionierung und Formgebung der Speicherhohlraeume gewisse Freiheiten, muss jedoch vorgefundene geologische und geotechnische Bedingungen beruecksichtigen. Der vorliegende Beitrag gibt zunaechst einen allgemeinen Ueberblick ueber die geotechnische Planung von bergmaennisch aufgefahrenen Speicherhhohlraeumen. Darueber hinaus werden Besonderheiten betrachtet, mit denen das Elgas LPG-Speicherprojekt in einer bergmaennisch aufgefahrenen Kaverne in Sydney, Australien konfrontiert war. Hierbei ging es um die Beruecksichtigung anisotroper Bedingungen mit zusaetzlichen Heterogenitaeten im Gestein und den daraus erwachsenden Schwierigkeiten, die geplante Hohlraumform zu verwirklichen. Ueber einen Zeitraum von fast 10 Jahren, in denen das jetzt in Betrieb befindliche Projekt unterschiedliche Betriebsphasen durchlaufen hat, wurden verschiedene geotechnische Entwurfsverfahren auf ihre Anwendbarkeit geprueft. SCHLUESSELWOERTER: Untergrundspeicherung, Geotechnik, Stabilitaet, Entwurfsverfahren, Planung. RESUME : Le stockage souterrain d’hydrocarbures est un domaine très spécifique pour le concepteur, car celui-ci dispose d'une large liberté pour adapter les sections, les formes et les implantations aux conditions géologiques et géotechniques de l’environnement choisi. Après un panorama de la conception géotechnique des stockages souterrains d’hydrocarbures par la méthode dite des cavités minées, l’accent sera mis sur un certain nombre de particularités rencontrées lors du projet de stockage de GPL de Elgas à Sydney en Australie, creusé dans de très fortes conditions d’anisotropie du massif rocheux, avec de nombreuses variations locales et toutes les implications que cela peut avoir sur le maintien des formes. L’évolution des approches méthodologiques géotechniques durant la dizaine d'années de développement de ce projet depuis les premières études jusqu'à l'exploitation actuelle est également présentée. MOTS-CLEFS : stockage souterrain, géotechnique, stabilité, méthode, conception.

Jan 1, 2003

By David K. Hylbert

This study investigated stratigraphic and structural causes of roof falls in room-and-pillar drift coal mines in nine mines in eastern Kentucky. A contract modification provided for remote sensing studies in the Dunkard Basin of West Virginia and Pennsylvania. Results of stratigraphic and structural studies of an earlier contract (H0133018) were applied to several new mines. It was found that similar rock sequences contributed to unstable roof conditions. Structure contour and isopach maps were found useful In projecting these trends together with fence diagrams. Using Landsat imagery, a direct relationship was found between lineament direction and the trends of rock jointing, roof fall zones, "snap top" zones and sandstone channels in the examples cited. It was found that, by analyzing lineament intersections, from 50 percent to 65 percent coincided with roof falls.

Jan 1, 1980

By Joseph L. Petrillo

In July 1997, Kvaerner Environmental signed a unique contract with Echo Bay Alaska called the Transfer Risk and Accelerate Closure (TRAC). The contract called for Kvaerner to assume the responsibilities and obligations associated with closeout of the Alaska-Juneau (A-J) Mine. Kvaerner is an international engineering and construction company with global interdisciplinary experience in the mining industry and environmental remediation. Echo Bay’s requirements called for Kvaerner to: •Provide a fixed price for closure with no change orders. •Negotiate, prepare and implement a final closeout plan as outlined by Echo Bay. •Complete a closure program that exceeded current regulatory requirements. •Improve, expand and maintain a proactive public and community relations program. •Hire Echo Bay employees where possible. •Provide adequate performance guarantees and judicial relief of environmental claims.

Jan 1, 1999