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By Misra V. N

Upgrading of a Koolanooka magnetite iron ore sample provided by Kingstream Steel Ltd was investigated using low intensity magnetic separation (LIMS) and reverse flotation. The ore contained 38.6 per cent iron, 37.8 per cent silica, 6.5 per cent magnesia and 0.54 per cent alumina, with the main minerals in the ore being amphibole (42 per cent), magnetite (39 per cent) and quartz (14 per cent). The concentrate obtained after low intensity magnetic separation contained 66.6 per cent iron and 6.34 per cent silica with an iron recovery of 72 per cent. This concentrate was further treated by reverse flotation to increase the iron content and reduce the silica content to meet the requirements for direct reduction iron (DRI) feed grade.

Jan 1, 1999

By Ramón Estrella

El presente texto describe el "Smooth Blasting", como un método de voladura controlada que posibilita la superficie de corte lisa y evita el agrietamiento excesivo de la roca. Entre los objetivos principales del método tenemos: el aprovechar la misma roca como pared directa del pique y así desarrollar el empotramiento de puntales de pino, eliminando los cuadros convencionales. Asimismo, genera una superficie lisa de la roca residual que desaparece la rotura y aprovecha las condiciones de la roca existente de la zona.

Nov 8, 1984

By Robert H. Peters

This U.S. Bureau of Mines report identifies the types of serious accidents that occur most frequently at small underground coal mines and describes the strategies that could help prevent these accidents. A wide variety of methods for improving safety are suggested, including improvements in the design of equipment, work procedures, work schedules, safety programs, and emergency response plans, as well as techniques for diagnosing the potential hazards associated with new technologies and work procedures. Some of the papers in this volume focus on preventing specific types of mining accidents-ones associated with materials handling (primarily back injuries), equipment maintenance, improper machine guarding, and ground failure during retreat mining. Although the recommendations in this volume are heavily influenced by research performed at underground coal mines in the Appalachian coalfields, most of the papers contain advice that is equally pertinent to almost any type of mine.

Jan 1, 1994

By J. C. Thornley

Service failures of seemingly conventional galvanized bolts, in normal operation, on transmission towers in New Brunswick have been found to be the result of hydrogen cracking. In both these cases, similar failures elsewhere can be avoided by suitable clauses in the purchase specifications. In the first case described, the manufacturing procedure was responsible for strengthening and embrittling a standard, soft, constructional steel. In this case, a fracture mechanics analysis predicted critical crack depths for final fracture very similar to those found in practice. This case reveals an apparent cooperative connection between hydrogen embrittlement and strain ageing in plain carbon steels. In the second case described, the steel was simply a high strength steel which should not have been made into galvanized bolts.

Jan 1, 1979

By Christoph Broeckmann, Andrew Gardula

"The adoption of high-pressure grinding throughout the cement industry has yielded enormous savings in energy and wear material costs. There are also a number of installations, which are applied in iron ore and kimberlite processing operations. High pressure grinding offers the same potential for energy and media savings, as well as opportunities for improved, downstream metallurgical performance, in hard rock mineral processing. This paper focuses on developments in machine design and wear surface engineering for high-pressure grinding of the hard rock ores in the mineral processing industry.INTRODUCTIONIn the early eighties 3.4 % of the world electric energy was consumed for crushing and grinding operations of minerals and 0.6 % in the ore dressing industry. During that time using a laboratory press Prof. Schönert found that interparticle comminution at high pressure requires remarkably less energy as conventional grinding technologies. In grinding of cement clinker he expected energy savings between 33 and 50 % compared to ball mills [1]. Piston presses are limited in throughput. Thus, the principle of interparticle comminution was adapted by the use of high pressure grinding rolls (HPGR) to a continuous plant process. Figure 1 shows the main components of a roller press: The roller nip of width s is formed between the floating roller (1) and the fixed roller (2). The diameter of the rolls will be denoted with D, the width with B. The total press force F can be adjusted using a hydraulic system with two or four pistons (3). In order to compare machines with different roll geometries the specific pressing force p is introduced:"

Jan 1, 2005

By Richard A. Rivell

This document is a users manual intended as a reference for personnel interested in the analysis of coal-mine-electrical-power systems under either normal operating conditions or fault situations. The interactive procedures developed for this purpose are described and implementation considerations are discussed with respect to the mine-power system. Considerations for choosing a solution technique and a number of examples are included. Procedures available include Gauss-Seidel and Newton-Raphson iterative techniques for the analysis of normal operation or balanced faults as well as a non-iterative Z-bus technique for analysis of unbalanced or balanced faults.

Jan 1, 1980

By R. Sullivan, K. Joiner, B. Emery, M. de Vries, F. A. Stober, L. R. Nelson, J. M. A. Geldenhuis

Keywords: Pyrometallurgy, smelting, converting, furnace design, furnace retrofit, high-intensity smelting, copper coolers, plate coolers, waffle coolers, tap-blocks, lower sidewall air-cooling, wall hold-down system, platinum group metals, ferroalloys, ferrochrome, ferrocobalt, ilmenite smelting, ironmaking, operational readiness, operational support The paper describes the development of furnace designs by Hatch in conjunction with the smelting plants in Africa to meet the intense process requirements in certain applications; continued improvement in operating efficiency through increased throughput from existing crucibles; and improvement in campaign life and furnace integrity. The era of Hatch in Africa has seen the doubling of furnace power in retrofit projects using existing crucibles to developing the highest intensity immersed electrode operations in the world. This has resulted in minimized OPEX and CAPEX per unit of production. Through the continued development of its cooling, binding and furnace power supply technologies and working with the experienced and knowledgeable personnel at the smelting facilities in Africa, Hatch has managed to meet the challenges of ever increasing furnace process requirements associated with increased power density and superheats prevalent in the operations. In addition to developing furnace crucible designs, Hatch has also intensified its ?after sales service and support? with the construction, commissioning and start-up technical assistance and operational readiness and operational support for ramp-up to nameplate capacity and beyond. The key areas of furnace risk associated with high superheat molten material tapping has also seen the development of diagnostic systems to mitigate risks and produce early warning signals for the operators.

Jan 1, 2006

Wetting Characteristics of Mineral Surfaces - Contact Angle Measurements through Molecular Dynamics Simulations

Sep 13, 2010

By Rocío Cruz, Joseph Chancasanampa

Constantemente las operaciones mineras están buscando como optimizar y reducir sus costos de operación, bajo esta premisa en la planta concentradora “Victoria” se realizó una serie de investigaciones para buscar nuevas alternativas en los reactivos de flotación que nos permita reducir los costos operativos. Como resultado de las evaluaciones metalúrgicas se logró remplazar parcialmente al Sulfato de Zinc con el Depresor RA-116 y se redujo su consumo en un 50%, esto significó un ahorro de 0.5 $/tn.

Sep 29, 2023

By Bin Tang, Suping Yao

In the last decade, the copper industry in China has developed rapidly and attracted the world’s attention. The production capacity of refined copper has grown remarkably from 4.578 million tons in 2010 up to 9.029 million tons in 2018, accounting for about 40% of the global refined copper production. And now, China has become the biggest refined copper producer in the world. This paper summarizes the application of modern copper metallurgical technologies such as Outotec flash smelting/converting technology, Cyclone smelting technology, TSL (ISA/Ausmelt) smelting/converting technology, Jinfeng side blown smelting and Baiyin side blown smelting technology, Chifeng side blown smelting and continuous top blown converting technology, SKS bottom blowing technology, Dongying two-step smelting technology, copper electrorefining with high current density, etc. in China’s copper industry, analyzes and compares the characteristics of those technologies and presents the great efforts of China’s copper smelters in adapting to the increasingly strict emission standards and improving economic benefits of copper smelters. INTRODUCTION China has been the biggest refined copper producer in the world for many years. China produced million tons of refined copper in 2018, accounting for 40% of the copper smelting production in the world, and of which, roughly, 70% of the copper concentrate was imported, mainly from Chile, Peru and Australia. ICSG (International Copper Study Group, 2017) shows clearly the position of top 20 countries of copper production and copper mine production (Figures 1 and 2). Blast Furnaces, Reverb Furnaces and Electric Furnaces dominated China Copper Smelting for quite long time till 1980s. The first modern copper smelting technology (flash copper smelting) was introduced into China in 1980s, then followed by Noranda, Ausmelt and ISA. Since then, China copper smelting technology stepped into modern time. Since 2000, old processes (Blast Furnace, Reverb Furnaces and Electric Furnaces) were phased out and replaced by modern smelting technologies. China Copper Production has been increasing dramatically (Figure 3).

Jan 1, 2019

By Karl Marquis

La Mine Mouska exploite depuis deux ans certains blocs de réserve à l?aide de la méthode long trou. Même si, à priori, la méthode long trou semble rentable, le contrôle de la dilution ainsi que le respect d?un échéancier serré s?avèrent primordiaux afin que cette méthode d?exploitation puisse être justifiable économiquement. La présentation suivante fera la comparaison économique entre cette méthode et celle de chambre-magasin.

Oct 1, 2001

By R. E. Head

[Recent investigations at the Intermountain Experiment Station of the Bureau of Mines at Salt Lake City indicate that metallurgists have given little attention to the occurrence of jarosite minerals in the oxidized ores of lead and silver. These investigations have also emphasized the importance of lowing when these minerals occur in the oxidized ores, especially those containing lead, silver, and gold, as their presence is a material factor in selecting a suitable kind of treatment. Since the question of the occurrence of jarosites in oxidized ores has come to the attention of the Bureau of Mines, investigation has indicated that plumbojarosite and argentojarosite are quite common. These two minerals appear to be widely distributed and probably escaped recognition by persons who had attempted to treat certain oxidized lead ores in which the jarosite minerals represented a material portion of the metal content. Consideration of the physical characteristics of the jarosites also indicates that in many cases failure to treat some of the oxidized lead ores with success has been directly due to the fact that the greater portion of their lead and silver content was present as plumbojarosite and argentojarosite. The data and the description of these minerals given in the body of this paper indicate that attempts to recover lead and silver from ores in which appreciable amounts of too metals occur is plumbojarosite and. argentojarosite would be unsuccessful if confined to gravity methods of concentration. There are undoubtedly considerable tonnage of oxidize lead ores in the various mining regions of this and other countries, and it is quite probable tat in some of these ores the metal content of lead and silver may be largely anglesite (lead sulphate) and cerussite (lead carbonate) but that they will also contain cerargyrite (silver chloride), argentojarosite, and plumbojarosite. The treatment of such ores therefore presents an important problem, since a product is discarded from]

Jan 1, 1928

By Alvin J. F

Tin in ores containing 0·025 to 1·5 per cent tin can be determined polarographically by the reduction of the chlorostannite ion at the dropping mercury electrode in 2M hydrochloric acid solution containing 15 per cent ammonium chloride. The tin is separated from interfering elements by distillation as the tetrabromide and collected from the distillate by co-precipitation with aluminium hydroxide. The method can detect 0·01 per cent tin in ore.INTRODUCTIONAn iodimetric method, suitable for routine analysis of titrating tin in concentrations down to 1 per cent, has been available for some years (Low, Weinig, and Schoder, 1939).As concentrations fall below 1 per cent tin, there is increasing difficulty in obtaining a distinct end point due to large amounts of iron and silica normally present after fusion of the ore. Since concentrations of tin down to 0·02 per cent are significant in ore dressing products it was necessary to examine methods to determine such low concentrations, and to adapt these to tin ores containing a wide variety of other minerals.EXPERIMENTALDigestion and separationCassiterite, the principal tin mineral, is refractory but readily attacked by a sodium peroxide flux to yield soluble sodium stannate. In a recognized procedure, a sample of ore is mixed with up to 15 g of sodium peroxide in an iron crucible and swirled over the full heat of a Meker burner for 7 min. The fusion is leached with water and acidified.This solution then contains tin, silica, and other soluble...

Jan 1, 1962

By R. T. Stain

Dynamic methods of load testing piles using a drop hammer to generate the input force have been in use for many years. These systems are based on the wave equations developed at the Case Institute of Technology, Cleveland, Ohio in the late 1960's and are well documented. Such tests are generally restricted to preformed driven piles, the driving hammer being a convenient means of generating large input forces. In 1979 the CEBTP (France) was sponsored by the FNTP (Fédération Nationale des Travaux Publics) to undertake research into existing classical methods and to develop a test that would be equally applicable to bored cast in place piles. The result of this research programme is a methodology known as SIMBAT, and which was included in a series of class A prediction trials in Belgium in 1987 (Refs 1 & 2, Paquet 1987, 1988). The purpose of this paper is: a) to examine the type of 'dynamic'/'static? load test correlations that can be obtained. b) to highlight the differences between the classical' methods and the 'SIMBAT' technique.

Jan 1, 1989

By E K. Leeka

Process control limitations have led to suboptimal performance of the crushing section of Sishen MineÆs Jig Plant. The performance of the PID (proportional-integral-derivative) controller implemented during commissioning was hampered by the relatively small buffer capacity between the crushers and screens. The inability to maintain the tertiary crushing chamber under full choke conditions lead to inefficient crushing and reduced crusher product cubicity.Model predictive control (MPC) was implemented in the tertiary crusher plant in May 2012 and resulted in a throughput improvement of six per cent in its first month. The controller was further optimised and indicated a throughput improvement of 16 per cent during on/off testing in July 2012. The throughput improvement is attributable to the finer crusher product resulting from operating the crusher under full choke conditions and controlled feed rate to the tertiary crusher plant screens. The next step is to couple the model predictive controller, automated gap control system and an economic optimiser to ensure maximised throughput and value from the resource.CITATION:Leeka, E K, 2013. Performance of model predictive control on the crushing circuit at Sishen Mine, in Proceedings Iron Ore 2013 , pp 417-420 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Walter E. Lewis

The Fort Randall Reservoir project, on the Missouri River at Pickstown, S. Dak., was designed by the Corps of Engineers and is part of the Missouri River Basin Development Program. The location of the project with respect to adjacent features is shown' in figure 1. When the project is finished, it will include a large earthwork dam and 12 circular tunnels, 8 of which will be equipped for power and 4 for flood control. Various phases of the construction have been contracted to independent companies, and at present four companies are working on different phases of the project under a rigid time schedule. Western Contracting Corp. is the contractor on stage II, earthwork; Johnson-Winston Construction Co. is the contractor for construction of the intake towers at the upstream side of the dam; McCarthy Improvement Co. has the contract for the power house and the outlet works on the downstream side; and Silas Mason Co. has the contract for driving the power and flood-control tunnels. The latter two companies use the same roads for ingress and egress to their respective work areas and the same general waste dump area. Under such circumstances, it is necessary that each company stay on a time schedule in regular sequence to avoid interference with the other.

Jan 1, 1951

By Fred W. Johnson

The first section of this circular has been prepared with a view to answering inquiries frequently received by the Bureau regarding laws governing the staking of claims and regulations covering requirements for holding them and obtaining title in fee to placer ground. These laws and regulations were summarized briefly in Information Circular 6796, "Placer Mining in the Western United States." These laws, however, are administered by the General Land Office, Department of the Interior, and it has been considered advisable to combine an authoritative résumé thereof by the Commissioner of that Bureau with information on small-scale placer mining previously published by the Bureau of Mines. The second section of this circular is largely a revised reprint of Information Circular 6611, "Small-Scale Placer Mining Methods", first published in April 1932 for the purpose of answering the many daily inquiries then being received on this subject. This circular has been reprinted repeatedly, and about 30,000 copies have been distributed, most of them in response to applications therefor. At present (June 1937) requests for this publication continue to be received daily.

Jan 1, 1938

By L. F. Reinartz

ANOTHER year has rolled by. We are twelve months further away from the start of the depression and. therefore that much nearer to recovery. The accumulated needs and wants 'of our lame, virile population are ready to burst their bonds as soon as confidence returns and credit is stabilized. The steel industry has been harassed by uncertainty of the Government's attitude toward organized labor's de¬mands, and irregularity in volume of production. Steel labor, if left to its own devices, would in most instances, march shoulder to shoulder with the management of steel plants in their effort to pull the industry nut of the ?red.? Cooperation between management and men has improved considerably during; the year.

Jan 1, 1935

Overview ?G-9 Discovery Hole 420 drilled May 2005 ?14.16% Zn, 1.76% Cu ?Greenfield discovery built into the G-9 Mine in under 4 years. ?Utilized a unique ?Parallel Track? approach to fast-track mine development. ?Raised over $200million in financing without a Feasibility Study. ?Mine built for $149.7 million, only 20% over PEA. ?Commercial Production declared April 1, 2009. ?G-9 Mine has now completed the first year of commercial production on April 1, 2010. ?Initial cash costs per pound of zinc US$0.39/lb -US$0.45/lb range. ?Mill operating at over1,900 tpd in March 2010, well above design capacity (1,500tpd) only one year after starting commercial production. ?Balance Sheet -$167 million assets, $24 million long-term debt, $22 million cash. ?Restarted Exploration ?excellent initial results. ?Strategically positioning Farallon to grow to a mid-tier mining company.

May 1, 2010

By Jim Frazier

Tradition has often dictated low design load stresses on piles. Such traditions often developed prior to modern static or dynamic pile testing methods and perhaps result from a few limiting situations. These low stress limits were then broadly applied, even in cases where the piles could carry substantially higher loads. With sufficient testing to prove the design, higher design loads may present significant overall savings to the project owner. The cost of the testing then becomes an insignificant cost compared to the potentially great benefit of increased pile loadings. To confirm higher load possibilities for driven piles, the pile is tested either statically or dynamically. Further savings and increased testing efficiency result from remote dynamic pile testing. This paper presents a project where design stresses were considerably increased as a result of additional testing and use of remote dynamic pile testing equipment.

Jan 1, 2002