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By Roberto Parada

In a long term program for the optimization of the Outokumpu Flash Smelting Furnace at Chagres Smelter many different subprograms are being developed. One of them is the design and application of a sampling method that can allow the direct diagnostic of the quality of the copper concentrates combustion. We present in this paper the evolution of the sampling devices used in a ten months of continuous sampling campaigns and an example for the sulfur elimination and magnetite formation in the flame from 60 cm to 100 cm under the burner. These type of information combined with the appropriate mathematical modeling of the combustion must propose some considerations to correct the classic criteria in the preparation of the charge for the smelting of copper concentrates based only on the mass and energy balance from the chemical and mineralogy composition of the concentrates.

Jan 1, 2006

By Lee Ann Arrington-Webb

Thiele Kaolin Co. has invested much time and money in achieving and maintaining its IS0 9002 certification. Through a regimen of process control and documentation, routine audits and a commitment to quality management, this kaolin producer is a competitive pigment supplier in a worldwide market. Background In 1987, the International Organization for Standards developed the ISO 9000 quality management system. This series of standards is used as a means to ensure customers that a quality management system is in place. Certification of a company does not mean that an individual product is of high quality. Rather, it demonstrates a supplier's ability to meet its customers' product and service needs. It also shows that a company has documented records to assure product consistency. The ISO 9000 system was begun in England during the early 1980s. During the mid-1970s, the British manufacturing industry was experiencing low quality. In an attempt to boost quality standards, the British government established the BS 5750 standards system. In 1987, BS 5750 was incorporated into ISO 9000. The ISO 9000 series consists of three levels of certification. ISO 9001 is the model for quality assurance in "design/development, production, installation and servicing." This standard applies to companies that rely on research and development to bring products that frequently change to market. ISO 9002 involves "production and installation" only. This standard is relevant to industries that produce a specific product according to specifications - either their own or their customer's. ISO 9003 is the model in "final inspection and test." This standard is the least detailed of the 9000 series. It is also the most applicable to companies that purchase, inspect or sort and resell. The quality system requirements for certification are outlined in the 18 elements of ISO 9002. These include: 4.1 - Management responsibility. 4.2 - Quality systems. 4.3 - Contract review. 4.4 - Design control. 4.5 - Document and data control. 4.6 - Purchasing. 4.7 - Control of customer-supplied product. 4.8 - Product identification and traceability. 4.9 - Process control. 4.10 - Inspection and testing. 4.11- Control of inspection, measuring and test equipment. 4.12 - Inspection and test status. 4.13 - Control of nonconforming product. 4.14 - Corrective and preventive action. 4.15 - Handling, storage, packaging, preservation and delivery. 4.16 - Control of quality records. 4.17 - Internal quality audits. 4.18 -Training. Continuous improvement, though implied in maintaining these requirements, could potentially be included in the quality system requirements in the next revision. The ISO 9000 requirements and documentation system is shown in the hierarchy pyramid (Fig. 1). A company's quality policy serves as the top of the pyra-

Jan 1, 1997

By B. W. J. van Rensburg, M. J. Schmidt

Bulk materials handling systems are extensively used in the mining and minerals industry, where a fairly high incidence of structural failure is experienced, notwithstanding design compliance with appropriate standards. A number of case studies are explored to demonstrate how insufficient controls or protection systems have contributed to structural failures on mobile bulk handling equipment. The importance of design integration across engineering disciplines is highlighted. The revision of ISO 5049-1 (1994) is proposed to provide specific rules and guidelines pertaining to machine protection systems. It is further recommended that the structural design engineer of the original equipment manufacturer(OEM) fulfils a more prominent role during the final acceptance and handover of mobile bulk handling equipment, with specific reference to protection systems.

Jan 1, 2015

By D. L. Neylan

The Bureau of Mines evaluated various methods for identifying sources of mercury vapor in excess of the threshold limit value (TLV) of 0.05 mg of mercury per cubic meter of air set by the American Council of Government and Industrial Hygienists (ACGIH) for mines and mineral processing plants. Chemical spot tests and portable devices for mercury determination were evaluated, based on information from published sources and performance in laboratory tests. Among the parameters examined were sensitivity, interferences, cost, ease of use, and other factors pertinent to field application, More than 50 methods were evaluated. The investigators found that many readily available methods are suitable for identifying sources of mercury vapor in mines and mineral processing plants. The best method appears to be one that uses a commercially available mercury test paper sensitive only to mercuric ions. For some of the more promising chemical spot tests, this report includes step-by-step instructions for field application.

Jan 1, 1983

By L. Yuan, J. H. Rowland

"In 1995 and 2003, the U.S. Mine Safety and Health Administration (MSHA) conducted surveys to determine the number of atmospheric monitoring systems (AMS) that were being used in underground coal mines in the United States. The survey reports gave data for the different AMS manufacturers, the different types of equipment monitored, and the different types of gas sensors and their locations. Since the last survey in 2003, MSHA has changed the regulation requirements for early fire detection along belt haulage entries. As of Dec. 31, 2009, point-type heat sensors are prohibited for use for an early fire detection system. Instead, carbon monoxide (CO) sensors are now required. This report presents results from a new survey and examines how the regulation changes have had an impact on the use of CO sensors in underground coal mines in the United States. The locations and parameters monitored by AMS and CO systems are also discussed.IntroductionThe last survey conducted by the U.S. Mine Safety and Health Administration (MSHA) on atmospheric monitoring systems used in underground coal mines in the United States was in 2003 (Francart, 2005). A total of 146 active mines were surveyed. The survey report states that since 1995 there had been a steady increase in the use of atmospheric monitoring systems in underground coal mines as the technology of carbon monoxide (CO) sensors was improved by manufacturers. Atmospheric monitoring systems had become more reliable, and some CO sensors could be purchased with the capability to discriminate between the CO produced by a fire versus CO produced by diesel equipment. This increase in reliability had reduced the number of false alarms and the response time. The faster response time to a developing fire allowed miners to take the necessary action to put out the fire or exit the mine.At the time of the last MSHA survey, some mines still used point-type heat sensors to detect the presence of a fire on conveyor belts. This detection method works by measuring the temperature of the air around the sensor. As a fire starts to develop, smoke and hot gases are produced from the combustion process, and the air is heated up. Once the air and gases reach a designated temperature detected by the point-type heat sensor, a fire alarm signal is generated. Studies have shown that the response times for detecting the presence of a fire using CO sensors are much shorter than when using point-type heat sensors (Conti and Litton, 1995)."

Jan 2, 2018

By Bauduin C. Besix

The Eurocode 7 "Geotechnical Design" is based on "Limit State Design", tackling the uncertainties as much as possible at their source through: - selection of characteristic values of variables (loads, soil properties, pile resistance,...); - partial factors applied on the characteristic values; - model factors to account explicitly for uncertainties of the calculation rule if necessary. Eurocode 7 will propose three "design approaches". The selection of one of them will be by National Determination. For pile design, the approaches are: - approach 1 is a "material factoring approach" at load side and a "resistance factoring approach" at resistance side. The structural and geotechnical design are checked for both of two separate sets of partial factors. - approach 2 is a "load and resistance factoring approach" and is in several aspects close to a deterministic approach. The design is checked for one set of partial factors. - approach 3 is a material factoring approach, at load as well as at resistance side. The design is checked for one set of factors. The aim of this paper is to introduce to the design of pile foundations based on pile load tests and on ground test results (semi-empirical and analytical methods) in the frame-work of the three design approaches. Detailed attention is devoted to: - the selection of the characteristic value of the pile resistance, accounting for spatial variability and stiffness of the structure; - the reliability of the prediction of the pile resistance using analytical or semi-empirical methods which may be accounted for through a "model factor". The results of a large test campaign on screw piles in OC Clay and a calculation example illustrate the proposed procedure when calculation rules using CPT results are used.

Jan 1, 2002

By A. B. Campbell

The mines in the eastern part of the now active region of the Tri-State zinc district of Missouri, Kansas, and Oklahoma have unusually acid water, which during periods of moderate or no rainfall As used in the mills to replace losses from evaporation, seepage, and tailings disposal. Its use has caused difficulties by corrosion of equipment and by interference with flotation. The growing importance of flotation- Which requires good water, and the increasing troubles caused by the corrosion of the milling equipment have prompted the Mississippi Valley Experiment Station of the United States Bureau of Mines, in cooperation with the Missouri School of Mines and Metallurgy, Rolla, Mo., to investigate the action of the waters on flotation and to undertake to develop means of obviating their harmful effects.

Jan 1, 1932

By Roddick F

From its mining lease at the northern end of Cohens Reef at Walhalla in the North Gipps- land mountains, the Long Tunnel Extended Gold Mining Company produced 13,695kg of gold, which at 1982 prices represents a value of about $140 million. In the period 1885 to 1908 the mine was one of Australia's principal reef gold producers, being top Victorian producer in six of these twenty-four years. Prior and subse- quent occupants of the lease produced an addit- ional 160kg of gold. The Extended and the other mines on Cohens Reef whilst contributing importantly to the financial resource of Victoria, were the sole important support for the substantial town of Walhalla that had grown up around them. When the mines closed, Walhalla gradually reduced from a bustling developed town to the present attractive mountain village so favoured by tourists.

Jan 1, 1982

By Chuang Y-Y

A summary is made on the thermodynamic analysis for two of the four ternary systems of the quaternary Cu-Fe-Ni-S. The analysis is being extended to ternary Cu-Fe-S and then to the quaternary. An analysis is already made for the metal ternary but is not reported here. Experiment is being carried out to measure the liquidus surface. of Fe-Ni-S equilbrium with the fcc solid solutions of (Fe, Ni). The presentation at the Symposium will include all the results obtained at the time of presentation.

Jan 1, 1983

By Crazy Horse - The Journal of Explosives Engineering - Vol 20 No 1

The crew at Crazy Horse Memorial has produced a w o n d e rful new video called “The Fine Art of Mountain Carving.” The video closely examines for the first time, the extraordinary explosives engineering on the Crazy Horse mountain currently in pro g ress in the Black Hills of South Dakota. The 56-minute video takes the viewer up the mountain for a behind-the-scenes look at the drilling and blasting crew at work on the mountain. The video was written, edited and produced by Robb D e Wall and is available exclusively from the Crazy Horse Memorial in both DVD and VHS formats. For i n f o rmation, see www.crazyhorsememorial.org The following, is a brief summary of the 25 steps involved in carving the mountain. The video goes into extensive detail on each of the 25 steps. Both those in the explosives industry and those outside the industry will find the video intere s t i n g .

Jan 1, 2004

By Gerald G. Griswold, Allan G. Provost

INTRODUCTION The Norad Expansion Project was located 10 miles southwest of Colorado Springs, Colorado, within Cheyenne Mountain. The expansion areas to be excavated would be adjacent to the existing underground Norad complex, which would remain in operation during the work on the expansion. The original complex had been constructed approximately eight years earlier and had been in full operation for approximately five years. Phase I, Excavation was awarded the Tiro Construction Corporation, a subsidiary of Harrison Western Corporation, Denver, Colorado, in the fall of 1970. Notice to Proceed was given to Tiro on 28 December 1970. The project owner was the U. S. Air Force, design was performed by the U. S. Corps of Engineers, Omaha District, who would also serve as the construction agency. [ ]

Jan 1, 1979

The Project ? $1.4 billion project ? 59,000 tonnes of nickel and cobalt ? Large resource base ? First production end of 2004 The Place ? Half the size of Vancouver Island ? Population 210,000 ? 43% Melanesian, 37% European, 12% other South Pacific groups, 8% other nationalities ? Tourism principal industry ? 1/3 of world?s nickel resources The Politics ? French Overseas Territory ?1998 Noumea Accord: increased local control over domestic policy ? Referendum on independence in 2014 ? Seeking more economic autonomy, less dependence on French support

May 1, 2002

El Indio, eighty percent -owned by Compania Minera an Jose Inc., a subsidiary of St. Joe Minerals, and twenty percent-owned by private Chilean investors, will open their new flotation and Carbon -In -Pulp plant near La Serena, 480 km (300 miles) north of Santiago, Chile, in early 1981. The underground mine, at an altitude of 4,270 m (14,000 ft), will produce about 1,270 mt per day (1,400 st per day) of ore containing about 2. 2570 Cu, and gold and silver to the extent of 16 and 254 g per mt (0.47 and 7.4 oz per st) respectively. While construction of the plant was underway, development ore, containing some 1,400 kg (45,000 oz) of gold, was shipped to the United States for recovery in a copper smelter. At El Indio the underground ore is rail-hauled to the mill a short distance from the portal where it is crushed, ground, and floated to produce a copper concentrate containing both gold and silver. The crushing plant also crushes waste for use as mine backfill. Approximately 92% of the copper and 60% of the gold and silver are recovered in the flotation concentrate. Flotation tailings, at a grade of 19 g Au and 116 g Ag per mt (3.4 oz Au and 0.55 oz Ag per st), are cyanided for 72 hours in six Pachucas with auxiliary air lifts for pulp transfer. Lime, cyanide, lead nitrate, and a phosphate are also fed to the cyanidation Pachucas. After cyanidation, the pulp is treated in four air lift Carbon-In-Pulp tanks equipped with external vibrating screens for carbon advance. Loaded carbon is stripped in two pressure vessels in parallel. Pressure stripping must be used because of the high altitude. Stripped carbon is dewatered in a spiral classifier before being reactivated in a rotary kiln and returned to the C. I. P. circuit. Pregnant solution is then sent to four banks of four Zadra cells for gold and silver recovery on steel wool. Zadra cell cathodes.are washed with the slimes being captured in a plate and frame filter. The filter cake and the washed cathodes are then dried on an infrared dryer and smelted in two stages to bullion bars. Published reports indicate that the total investment for this unique operation was in the neighborhood of $80 million.

Jan 1, 1981

By Robert M. Cox

The successful application of the science of rock mechanics to the practical problems of coal mine design requires the acquisition and reduction to useable form of large amounts of field and laboratory data, and the construction and analyses of numerous geostructural models containing a wide variety of geometric and physical strength variables. Typically, the rime constraints placed on a new mine design project coupled with the inherent complexities of a good rock mechanics study combine to limit the applications of rock mechanics to the most rudimentary level. To facilitate a better application of rock mechanics to mine design problems, an interactive software package has been developed for use on a graphic mini-computer system that serves to aid the engineer in the timely and efficient analyses of rock mechanics data and geostructural models. The first phase of the rock mechanics package solicits the input of the raw geologic and rock strength data, analyzes and arranges this data in a logical manner, produces complete listings and statisitical summaries of the various rock properties, and stores the data on magnetic tapes and disks to serve as a future Rock Mechanics Data Base. The second phase of the software package provides for the analyses of a variety of geostructural models using a wide variety of geometric variables coupled with the rock strength data stored in the Rock Mechanics Data Base. This software package allows for the evaluation of numerous geostructural mine models for the design and selection of mine roof support and pillar systems (see Table l).

Jan 1, 1982

By G. T. van Rooyen

The susceptibility of a low-alloy steel that has been hardened and tempered-826 M40 (EN26)-to embrittlement by strain aging during service was simulated by artificial aging of specimens at 100°C. It was found that the brittle transition temperature of both monotonic and cyclically strained material was increased by only about 25°C as a result of strain aging. It is concluded that the susceptibility of low-alloy steels in the hardened, tempered condition is less than that of low-carbon steel, and that such steels qualify for exemption of the periodic 'annealing' required by the Mines and Works Act.

Jan 1, 1986

By J. B. Mawdsley

From the view point of the mining engineer, the square-set method of stoping as practised at Butte, Montana, is one ?of the outstanding features of well conducted mining operations in that camp. The following information was obtained in the course of two months underground work in the Granite Mountain mine, during the summer of 1920, which is one of the properties of the North Butte Mining Company, situated on the well known Speculator vein. Most of the information was derived from personal observation and from discussions with various miners and with members of the staff. Geology The copper mining area of the Butte district is some two miles long by one and a half miles wide, a mineralized area in a great batholith of monzonite granite, locally known as the Boulder batholith. This extensive body of granite is traversed by several series of mineralized fault-fissures which differ in strike but generally dip steeply. Geologists agree that following the formation of the fissures, alkaline solutions ascended and decomposed the felspathic portions of the granite in the immediate vicinity of the fissure walls, and that these alkaline solutions were followed by cupiferous solutions which filled the fissures and replaced the granite next to the walls. A zone of oxidized ore, varying in thickness from 10 to 400 feet, overlies a sulphide zone containing chalcocite, enargite, bornite and chalcopyrite, with a small amount of quartz gangue. The veins are from 3 to 100 feet in width and contain, on the average, 3 per cent of copper, 2 ounces of silver, and 15 cents in gold per ton.

Jan 1, 1925

By Marek Dworzanowski

Dense medium separation (DMS) is critical to the operation of coal and diamond beneficiation plants. It is also utilised in iron ore, manganese, chromite and andalusite beneficiation as well as pre-concentration for platinum-bearing UG2 ore. Gravity concentration plays an important role in the processing of diamonds, coal, gold, platinum, titanium minerals, zircon, chromite, iron ore and manganese. The DMS and Gravity Concentration operations and technology in South Africa conference will focus on the operation of DMS and Gravity Concentration circuits in the South African Mining Industry. The current status of the technologies and equipment employed will be presented as well as future developments. The conference was set up to showcase South African DMS and Gravity Concentration operations and provide a forum where operators, technology and equipment suppliers can engage in knowledge sharing. The papers cover a wide spectrum of topics, including descriptions of operations, optimisation projects, new capital projects, equipment applications, process monitoring and process selection. Most commodities and unit processes associated with DMS and Gravity Concentration are covered. The conference venue was selected to be the CSIR Convention Centre in Pretoria. The CSIR has contributed to DMS research in South Africa and it is located not far from many coal, diamond, gold, platinum and chrome mines that extensively utilise DMS and Gravity Concentration in their beneficiation plants. I believe that the papers and presentations submitted for this conference will provide a valuable future reference for DMS and Gravity Concentration, thus making the work of all the contributors to this conference highly rewarding and worthwhile.

Jan 1, 2006

By Arun Vathavooran, Adrian Singh, Michael Fletcher, Rainer Imhof

The Imhoflot G-Cell, a new development in the pneumatic flotation technology (which incorporates centrifugal forces in the separating vessel) is a recent innovation in the mineral processing world. The G-Cell was invented by Dr Rainer Imhof and commercialised by Maelgwyn Mineral Services Ltd. In a short time span a number of plants and units have been successfully commissioned in the mineral processing industry. In addition, a number of industrial G-Cell flotation plants are in the process of construction for the purpose of coal preparation and environmental remediation. In this paper two industrial installations have been highlighted together with a pilot plant test programme investigating ultra fine flotation recovery for a base metal operation.

Jan 1, 2007

By Syed M. Tariq, Paul N. Worsey

Presplitting is a now a universally accepted perimeter control technique in rock excavation. The success of presplitting and the smoothness and integrity of the resulting perimeter is largely dependent on the nature of joints in any given formation. Many facets of jointing have been previously investigated. The results of the effects of joints frequency and spatial positioning were presented by the authors at the ISEE annual meeting last year. This paper includes the results of further research into the mechanism of presplit blasting being carried out at the Rock Mechanics and Explosives Research Center of the University of Missouri- Rolla.

Jan 1, 1996

By I. Iwasaki, K. A. Smith, X. Cheng

The reaction mechanism for the cathodic decomposition of pyrrhotite in deoxygenated solutions at natural, near neutral pH levels was studied using potential and cyclic voltammetric measurements. Reaction products on the pyrrhotite surfaces were examined by Auger Electron Spectroscopy (AES), by X-ray photoelectron spectroscopy (XPS) and by analyzing the voltammograms for the electron balance of the reactions. Surface properties of the pyrrhotite/solution interface were characterized using an ac impedance technique. The parameters of an equivalent circuit were determined by the nonlinear least-squares fit (NLLSF) technique. The effect of cathodic polarization on floatability was investigated by performing microflotation tests. Possible implications to the flotation separation of chalcopyrite-pyrrhotite ores are discussed.

Jan 1, 1995