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By Corby G. Anderson

Since 1985, the Sunshine Mining Company has used a patented nitric-sulfuric acid pressure leaching system for production of silver and copper from a refractory sulfide ore body. To better understand this novel process, a program of lab scale testing was undertaken to quantify the effect of system variables on silver recovery. Some of the factors studied include temperature, agitation, acidity, vessel pressure, particle size, percent solids and oxidizer amount. In turn, this knowledge will be applied in actual plant practice to upgrade reaction time, increase concentrate throughput, raise silver recovery and lower reagent costs. A discussion of plant process changes resulting from lab scale testing is included.

Jan 1, 1991

By Hamid Maleki

Prudent design of coal pillars in any mining system requires an estimation of in-situ pillar strength, overburden lateral load transfer capability, and a failure criterion. Pillar strength is typically determined using one of several different empirical pillar strength formulas. For coal reserves in the U.S., a new pillar design method was proposed based on extensive U.S. field measurements in underground mines (7) which accounted for confinement effects. Field measurements in seven U.S. seams indicated highest strength for some Utah mines where the coal seam developed high confining stresses. Lower strength was measured in structurally controlled seams. This method is expanded here including the data from the weaker tertiary coal measure rocks and lower confinement for pillars with low width-to-height ratios. The determination of how much load a pillar is expected to take is partially dependent on the ability of overburden to transfer load laterally; this is useful for selection of panel width and barrier pillars size in select mining applications where long-term stability is required in conservative designs. In caving mining systems, caving of the strata is influenced by geologic, mining and stress conditions and the released energies influences how the pillars react at loads approaching pillar strengths. Overburden deformation and caving mechanisms are analyzed in this paper in multi-panel extractions to enhance the understanding of load transfer, seismicity and coal bump control in deep western U.S. operations.

Jan 1, 2008

Once and for all, the debate on the exponent in Gy's formula is pushed to its limit. It is explained why an exponent of 2.5, obtained when using a square root of nominal size d to adapt the value of a calculated liberation factor to a different comminution size, will rarely be encountered in practice, if no arbitrary decisions are made.

Mar 1, 2010

By Jacques B. Wertz

Both the San Andreas fault complex and the Murray fracture zone are apparently found to be contemporaneous with the Laramide mineralization period. Their compounding effects certainly have disturbed the Texas lineament belt and its components with serious lateral offsets and most probably have been instrumental in allowing intrusives to be emplaced as well as mineralization to accompany these intrusions at some of the fracture intersections. While the main fracture centers can be almost accepted as being structurally linked together, the Texas lineament trend definitely predominates, exerting a prevailing direction to graben (Silver Bell) and to elongated depressions (Bisbee). That this lineament belt also influenced the concomitant mineralization seems a logical inference. The orebodies are generally found at intersections near the most centrally-located intrusive with a distance varying from contiguity to one or two miles. The Southeast Arizona copper province owes its existence primarily to a particularly favorable structural setting of broad semi-continental scope. Thus, various regional structural elements are to be considered as possibly direct or remote cause for the widespread mineralization, although the one or the ones really responsible may never be singled out. There arc three basic regional elements: (1) The north-northwest-trending anticlinorium that diagonally crosses Arizona is quite obvious because many mountain ranges follow this direction. This anti- clinorium, which merges northward into the Wasatch-Jerome Belt, marks a broad zone of weakness where tension seems to prevail. Mineralized trends such as Jerome-San Manuel-Bisbee may give some weight to the economic value of this structural element. (2) Northeast-trending fractures, parallel to the Colorado Mineral Belt (Landwehr, 1967), appear troincident with mineralization as evidenced by the Questa-Grants-Morenci and the Lordsburg- Tyrone-Santa Rita alignments. This structural direction is accepted as one of the most economically significant in the Southwestern United States. (3) The Texas Lineament.

Jan 1, 1970

By Hongfa Hu, Stavros A. Argyropoulos, Stephan Ferenczy

"Physical as well as mathematical modeling was carried out to investigate the exothermic mass transfer in liquid metal systems. In these systems, the exothermicity induces unique heat, mass and momentum transfer phenomena. Moreover, these phenomena are deeply coupled and they are further complicated by the presence of a moving boundary.In the physical model used, ice cylinders were immersed into sulfuric acid solutions, because the intermixing of ice with sulfuric acid is very exothermic. In this low temperature system, velocity and temperature measurements in the sulfuric acid were made as well as measurements of the ice melting in the sulfuric acid.The mathematical model developed solved simultaneously the heat, mass and momentum equations numerically, utilizing the control-volume finite difference approach. The enthalpy method was adopted to track the moving boundary. Predictions made by the mathematical model were in close agreement with the results obtained by the physical model.The results from the mathematical model were further validated with experiments involving high temperature liquid metals. Specifically, data were obtained in an experimental setup involving (a) dipping silicon cylinders into high carbon liquid iron and (b) dipping nickel cylinders into liquid aluminum. Results from these experimental studies supported the predictions of the mathematical model."

Jan 1, 1999

By William D. Macdonald

The Upper Devonian Kettle Point black shale of southern Ontario is poorly exposed. Structural maps pre-pared from the data of numerous wells show that the upper surface of the formation has low regular relief, and that the lower surface reflects domes in the Middle Devonian and also local subsidence of the Devonian rocks due to solution of salt in the Silurian Salina Formation. The appearance of minor amounts. of marcasite, pyrite, and calcite, m that order, as interpreted from the evidence of concretions from the type locality at Kettle Point is thought to have been influenced by a rise m the pH within anaerobic sediments preceding compaction.

Jan 1, 1960

By P. R. Thomas

The Bureau of Mines determined the costs associated with the production of chromium, in the form of chromite and high-carbon ferrochomium, from the demonstated resources of 10 market economy nations. The analyses evaluated the relative geologic and economic position of these chromite resources contained within 80 producing or potential mining operations. This report presents cost evaluations of a demonstrated resource of chromite, contained within the nations studied, of appoximately 1.2 billion metric tons (t). Of this total, 70 pct is contained within the southern African nations of Zimbabwe and the Republic of South Africa. The majority of current chromium mining and smelting capacity is contained within these two countries as well. India and the Philippines have recently demonstrated greatly increased chromite resources and hold the most promise for expanding both chomite and ferrochromium production outside southern Africa. Their demonstrated resources represent approximately 7 and 16 pet, respectively, of the cost evaluated total tonnage. Chromite resources, on an identified or hypothetical basis worldwide, are highly concentrated within Zimbabwe and South Africa, with these two nations containing in excess of 95 pet of the total. Given the present market structure, a majority of chromium contained within the demonstrated chromite resources of the nations studied is economically recoverable; but from a long-term resource and economic perspective, South Africa should inceasingly dominate the markets for both chromite and high-carbon ferrochromium. In addition, it is anticipated that an increasing percentage of chromium traded on the world market in the future will be in the form of high-carbon ferrochromium as opposed to chromite, as this additional processing stage continues to relocate from the industrial nations that account for a majority of chromium consumption to those nations that mine chromite.

Jan 1, 1984

By R. D. Brown

"AbstractIn order to raise the enormous amounts of capital which will be essential for the development of Canada's mineral and petroleum resources, this country's resource industry must be permitted to earn an acceptable rate of return. The existing tax regime, with its high rates, complexities and misdirected incentives, presents a serious obstacle to our resource industries in their development of Canada's immense , but increasingly lean, resources. Government tax and other policies are not the only cause of the crisis now facing the resource sector in Canada, but a reformed tax system, with stable and reasonable tax burdens, is required if Canada's resources of minerals, oil and natural gas are to continue to contribute in the future, as in the past, to our national well-being.An independent task force, organized under the auspices of the Canada West Foundation, has recently completed a wide -ranging report: on the future development of Canada's mineral, oil and gas resources. This five-volume report, completed after almost two years of research and study, concludes that Canada •is facing a major crisis •in the development of our resources, It states that unless corrective action is taken now, mineral production and exports could decline drastically after 1985, at the same time that Canada would face massive bills for imported oil because of inadequate and declining production.The task force, chaired by the author of this article, has put forward recommendations for a fundamental shift in both federal and provincial policies in order that Canada's mineral reserves can be developed in the national interest. This article consists of excerpts from the summary of the task force's report."

Jan 1, 1977

By Rajiv Kalra, Ji Jiangang

"This paper reviews the following aspects of the world’s largest manufactured Grinding Mill’s in terms of diameter and power, along with the world’s biggest shop assembly and trial run of the mills delivered to Sino Iron Magnetite Project in Australia.1. An overview of the basic flow sheet of the Sino Iron (Magnetite) Project located in Australia2. An overview of in-house designed CITIC Heavy Industries 12.2 m (40ft) F x 11 m(36ft) LG – 28MW AG mills including FEA and major components3. In-house manufacturing at CITIC-HIC work in Luoyang China of all major components for 6 off Ø12.2 m(40ft) AG mills and 6 off Ø7.9 m(26ft) x 13.6 m(44.6ft) LG – 2 x 7.8 MW Ball Mills4. Major aspects of design and preparation of the biggest shop trial run of Ø7.9 m(26ft) x 13.6 m(44.6ft) LG Ball Mill witnessed by international EPCM’s and clients in July 2009.5. Major aspects of one piece assembly of 1300 tonne rotating element of the Ø12.2 m(40ft) x 11 m(36ft) LG AG Mill and Ø7.9 m F (26) x 13.6 m(44.6ft) LG Ball Mill at the port of the export China and transport to Australian Port and then to site.6. An insight to unique installation methods used for Ø12.2 m(40ft) and Ø7.9 m(26ft) rotating element lifting on the mill foundation in one piece assemblies.7. CITIC Heavy Industries present capability for in house design and manufacture of Grinding Mills up to Ø13.7 m (45 ft) with 35 MW Gearless drives and Ø12.2 m(40ft) with 2 x 10 MW Geared Mill drives"

Jan 1, 2012

By Rajiv Kalra

This paper reviews the following aspects of the world?s largest manufactured Grinding Mill?s in terms of diameter and power, along with the world?s biggest shop assembly and trial run of the mills delivered to Sino Iron Magnetite Project in Australia. 1. An overview of the basic flow sheet of the Sino Iron (Magnetite) Project located in Australia 2. An overview of in-house designed CITIC Heavy Industries 12.2 m (40ft) F x 11 m(36ft) LG ? 28MW AG mills including FEA and major components 3. In-house manufacturing at CITIC-HIC work in Luoyang China of all major components for 6 off Ø12.2 m(40ft) AG mills and 6 off Ø7.9 m(26ft) x 13.6 m(44.6ft) LG-2 x 7.8 MW Ball Mills 4. Major aspects of design and preparation of the biggest shop trial run of Ø7.9 m(26ft) x 13.6 m(44.6ft) LG Ball Mill witnessed by international EPCM?s and clients in July 2009. 5. Major aspects of one piece assembly of 1300 tonne rotating element of the Ø12.2 m(40ft) x 11 m(36ft) LG AG Mill and Ø7.9 m F (26) x 13.6 m(44.6ft) LG Ball Mill at the port of the export China and transport to Australian Port and then to site. 6. An insight to unique installation methods used for Ø12.2 m(40ft) and Ø7.9 m(26ft) rotating element lifting on the mill foundation in one piece assemblies. 7. CITIC Heavy Industries present capability for in house design and manufacture of Grinding Mills up to Ø13.7 m (45 ft) with 35 MW Gearless drives and Ø12.2 m(40ft) with 2 x 10 MW Geared Mill drives

Jan 1, 2012

By P. Rambalee

A multiple coal fired boiler house provides steam for utility usage in various production plants. Maintaining stable header pressure and boiler availability is of critical importance for downstream consumers. Advanced Process Control comprising of a G2 based expert system and Model Predictive Control was implemented to improve the boiler house performance. The results yielded improvements in the main header pressure stability, reduction in boiler saturation and significant saving in coal consumption. All information used for this document is from a published whitepaper written and led by Prevlen Rambalee (Anglo Platinum) and Gustaf Gous (BluESP) titled, ?Control and Stabilization of a Multiple Boiler Plant: An APC Approach?.

Jan 1, 2012

By AIME AIME

TWO days of solid discussion, with barely time out for meals, characterized the Tulsa meeting of the Petroleum Division. It was preeminently an earnest gathering devoted to technical matters. Sessions were held in the Crystal room of the Mayo Hotel with luncheon served each day in the back of the same room so that talk of methods, while slightly less formal, extended right through the lunch hour. Thursday evening the Committee did provide a little relaxation in an informal dinner at the Tulsa Club where, after a brief musical program and an amusing skit by the local Herman the Great, brief addresses in non-technical vein were made by President Farish and Vice-president Rice of the Humble Company, Henry L. Doherty of Cities Service, Secretary. Bain of the Institute, and others. The presence of leading executives of a number of the oil companies at the dinner and the sessions, and the cordial approval they expressed of the work of the Division were especially gratifying. The total registration was 215 with 100 at the dinner and 70-to 80 lunching together each day.

Jan 1, 1930

By J. Bélanger, B. Semlali, M. Grenon

RÉSUMÉ La conception des fosses ainsi que l'évaluation des ressources géologiques et des réserves minières sont désormais réalisées entièrement à l'aide d'outils informatiques spécialisés. Cependant, plusieurs analyses, pourtant essentielles à l'évaluation de la viabilité du projet, sont réalisées en parallèle sans véritable optimisation ni synergie avec l'ensemble des données disponibles. Cet article présente deux approches permettant d'intégrer certains types d'analyses aux modèles de blocs miniers. Ces approches permettent de quantifier la broyabilité du massif rocheux ainsi que d'étudier la stabilité des pentes minières à même les outils d'optimisation et de planification minières. Cette méthode permet dès l'étude de faisabilité d'un projet minier de maximiser les données disponibles, menant ainsi à une approche plus intégrée en conception minière. De plus, ces approches sont flexibles et permettent d'évaluer rapidement plusieurs scénarios, tout en laissant la possibilité de bonifier le modèle et de revoir la conception tout au long du projet minier.

Jan 1, 2010

By D. Harrington

This circular presents Part III-A of a series reviewing the literature on effects of breathing dusts with special reference to silicosis; it deals with the economic and legal aspects of dust diseases in industry; Part III-B will contain data on the status and cost of compensation for silicosis, Parts I and II of the series have been issued as Information Circulars 6835, 6840, and 6848; Part I defines and classifies dusts, indicates sources of exposure, and describes the physiological effects of breaching dusts; Part II-A discusses the principal dust factors producing pulmonary pathology and methods of determination of dust in air; and Part II-B presents data on the engineering and medical control in the prevention of dust diseases and general recommendations for their control in industry. A summary and general conclusions will complete the series.

Jan 1, 1935

By A. U. Seybolt, R. E. Honnemon

THE purpose of this communication is to present activity data of nickel in the Ni-A1 binary system that was obtained for oxidation studies in this system. This data has been calculated from previous aluminum activity data at 1000°C1,2 by two types of Gibbs-Duhem integrations. These results should be of particular current interest to oxidation studies of aluminide coated nickel-base superalloys3 as well as other problems. The aluminum activity of Steiner and Komarek1 is plotted in Fig. 1 as a function of composition in Ni-A1 alloys at 1000°C. The dashed parts of the aluminum curves represent our approximate extrapolations from the directly measured regions. In the terminal solution regions (a and L phases) standard parabolic solution functions of the following form are assumed: where i is the component subscript, Ki is a constant at a fixed temperature, and xi is the atom fraction. The resultant nickel activity curve at 1000° C from the Gibbs-Duhem integration4 of the aluminum data is shown in Fig. 1. The solubility ranges of the phases present in the Ni-A1 binary at 1000°C are also denoted at the bottom of Fig. 1. Corresponding values of the nickel activity, aNi and yNi, are listed in Table I at useful compositional intervals. including phase boundary values. The aNi and yNi data listed in Table I are subject to the uncertainties present in the experimental aluminum activity data1 and to deviations from parabolic solution behavior in the terminal solutions. The errors introduced into aNi and yNi due to the parabolic solution assumption are expected to be relatively small (<20 pct of the values given) in all the phases except the liquid phase. Some deviation from parabolic solution behavior in the liquid phase is indicated

Jan 1, 1970

By Bunting S. Crocker

Pebble grinding was used at Lake Shore Mines in 1949. A full description of experimental evidence and test plant results was published in 1952 1 and further operating details in 1954.2 In more recent years the term autogenous grinding has been coined and is now frequently seen in the technical literature. Autogenous crushing and/or grinding covers any grinding mill in which the larger of ore are made to grind the fine pieces; the crushing and grinding may be either dry or wet. This discussion deals only with wet autogenous grinding, and only in the fine grinding part of the circuit, i.e., from 6 mesh to 92 pct -325 mesh. The term pebble milling could apply to fine autogenous grinding in which the pebbles are made from the ore itself, or it could also refer to grinding with pebbles, such as flint pebbles, from a source outside the mine.

Jan 5, 1959

"Chairman: Professor J. Elbrond Rapporteur: Miss V. E. MartingPapers.Aids to planning production in coal mines by F. H. Deist and M. P. RobertsCapacity calculations, investment allocation and long-range production scheduling in German coal mines by F. L. WilkeOre reserve evaluation and open pit planning by J. M. Marino and J. P. SlamaThis session was devoted to the economic aspects of planning and scheduling. After Dr F. H. Deist had introduced the paper Aids to planning production in coal mines, Dr T. V. Falkie summarized the following formal contribution prepared jointly with Dr R. V. Ramani, describing the work that has been done at the Pennsylvania State University in the development of simulation programs for mine planning over the past 15 years:During the late 50&apos;s and early 60&apos;s, Monte Carlo simulators were developed to model continuous miner-shuttle car transport systems, track haulage systems, belt conveyor networks, etc. In the mid-60&apos;s attention was directed towards deterministic simulation of equipment performance, given the equipment characteristics and the system profile. In the late (10&apos;s all these systems (miners, shuttle cars, belts and trains) were integrated together to form a complete coal mine simulator and the program could predict the output potential of the system, given the mining dimensions, method and equipment employed. The actual sequence of coal-cutting operations is entered into the computer through the use of a special programming language which permits any type of mining configuration to be simulated. The simulator is hybrid in nature in that the shuttle cars, trains and belts are simulated deterministically, whereas rate functions with delay frequencies are entered for the continuous mining operations of sumping, shearing, fleeting, cleaning, etc. With suitable manipulation of the data, the program may be applied to all belt or conventional mining sections. Most of these simulators were developed through the assistance of grants from the Department of Mines and Mineral Industries of the Commonwealth of Pennsylvania and are available from the Coal Research Board of the Commonwealth,"

Jan 1, 2014

By W. W. Agey

As a part of the program of investigation of domestic sources of manganese in the western United States, engineers of the Bureau of Mines examined. and obtained samples of ore from two properties in the vicinity of Barstow, San Bernardino County, Calif. In addition to these, samples from two other properties in the same vicinity were submitted by the owners. As the ores were too low-grade to be acceptable for the direct production of ferromanganese, beneficiation studies were made to determine the amenability of the ores to concentration by ore dressing. The Big Reef manganese claims axe about 140 miles east of Barstow, Calif. The claims were leased by W., E. Thurber of San Gabriel, Calif., from the owner, C. S. VanDoren of Daggett., Calif. Manganese oxides occur as a replacement deposit in heavily brecciated andesite along a fault plane. Four samples were taken by an examining engineer of the Bureau of Mines from the ore zone, which, when composited, were representative of all the exposed ore. Preliminary tests were made on lot B, and final tests wore made on the composite sample. The Trans-Oceanic property is about 20 miles southeast of Barstow, near Newberry, in the. Pisgah mining district, Calif. The sample, submitted by the owners, was taken from a 1,000-ton reject clump from a hand-sorting operation. The ore occurs as a replacement of rhyolite.

Jan 1, 1952

By Abhiram Shankar

Construction projects are becoming more demanding both in terms of time and complexity. This necessitates intricate planning and sequencing of activities at the macro and micro level and continuous flow of resources across the project in order to achieve planned targets. Work and Resource planning need to be done in such a way that limited resources give optimal output. Currently dominant activity-based scheduling techniques like Critical Path Method (CPM) and Program Evaluation and Review Technique (PERT) do not model work-flow or resource-flow through a project life cycle. An extension to the conventional activity based planning is Location Based Management System (LBMS). LBMS has been explored and utilised in the case of repetitive and cyclic projects such as high rise buildings. This study focusses on the application of LBMS to repetitive and non-repetitive components of Power Transmission and Distribution (PT&D) projects involving construction of substation and cable laying. This paper presents the findings on comparing the current planning practice for cable laying with an LBMS based approach. A key finding of the study was that the conventional practice resulted in a schedule with several coordination issues that could not be identified in the planning reports. Using the LBMS based approach these issues could be identified and decisions required for resolving these could be made.

Aug 1, 2013

By R. E. Scheffel

Most supergene copper heap leach operations today employ forced-aeration, irrespective of ore grade. Unfortunately, there is little published quantification of its benefit. There is a natural desire to strive for the ideal chemical kinetics. The reality, however, is that physical mechanisms control the commercial extraction rate. This paper presents the performance of a number of operations, their operating conditions and physical ore characteristics, which contribute to non-ideal solution distribution and variable extraction rate. Regardless whether one uses forced-aeration, commercial experience to date suggests it is prudent to design for longer leach cycle times to ensure the production target is met.

Jan 1, 2006