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By Manuel Arellano Ramírez

El presente trabajo refiere el proceso de construcción del primer complejo minero metalúrgico del Perú, la empresa Cerro Verde de Arequipa. Para ello, se revisan los antecedentes históricos, participación, financiación, inversión, organización y personal actual, producción y costos directos de operación, plantas y procesamiento, infraestructura e instalaciones auxliares, operaciones y desarrollo regional del proyecto minero.

Nov 20, 1978

By E. F. Adkins, R. W. Douglas

The variation of the spectral emissivity of osmium and ruthenium with temperature can be expressed by the following relations: DURING a study of the sintering characteristics of osmium and ruthenium, discrepancies in the previously accepted melting points of the metals were noted. The melting temperatures had not been measured at the time of the work, but were estimated in the literature as 2700°C for osmium and 2450°C for ruthenium.' A recent investigation by Baird2 has shown the melting temperatures of osmium and ruthenium are 3000" and 2250° C, respectively. In the present work, osmium bars sintered at temperatures as high as 2900° C showed no evidence of melting, whereas ruthenium showed definite evidence of melting at temperatures as low as 2250°C. In view of the apparent discrepancies, the melting temperatures of both metals were determined. The spectral emissivities of both metals were determined as an aid to studies of the sintering characteristics of these metals. MATERIALS AND PROCEDURES The materials used in these studies were metal powders supplied by Englehard Industries, Inc., through the courtesy of The International Nickel Co. Analytical data from three laboratories, although not in complete agreement as to the purity of the material or the major impurity elements, indicated that the maximum impurity levels were 0.5 and 1.0 wt pct in osmium and ruthenium, respectively. The metal powders were pressed to 1/4 by 1/4 by 6-in. bars at 20Tsi using carbon tetrachloride as a lubricant. The pressed bars were presintered 1 hr at 1200°C after heating 1 hr at 400°C. The presintered densities of the several bars of the metals ranged from 65 to 80 pct of ideal density. Specimens were self-resistance heated in a vacuum sintering bell. Temperatures were measured with an L&N, disappearing filament optical pyrometer. True temperatures were read at the base of an 0.30-in.-diam, 0.150-in. deep hole drilled into the center of a presintered bar. Apparent temperatures were read from the surface of the bar adjacent to the hole. MELTING POINT DETERMINATION The melting temperature of the metals was determined as the temperature at which a slight additional increase in current through the specimen resulted in a reduced temperature at the base of the hole. The apparent reduction in temperature is a result of the liquid metal filling the hole, thus altering the black-body conditions. The melting points of osmium and ruthenium, based on three deter-

Jan 1, 1962

By Y. Y. Li, T. T. Yang, R. X. Zhou, Z. H. Shen

"Wetting theory is one of the basic theories of flotation. The effects of concentrations, carbon chain length and pH values of saturated fatty acid collectors (lauric acid, myristic acid, palmitic acid and stearic acid) on the surface wettability of collophanite and dolomite were investigated by measuring the contact angle with dynamic captive-bubble technique and calculating adhesion work of bubble-mineral. The results show that the contact angles both of collophanite and dolomite are higher with enhancement of hydrophobicity when pH value of 5~9. The contact angles both of collophanite and dolomite are reduced with improvement of surface hydrophilicity. When strong acid pH value of 2~4 or strong alkaline pH value of 10~13. The reasons for this are that the fatty acids mainly exist with insoluble RCOOH molecules in strong acid condition, and competitive adsorption of OH- and RCOO- in the mineral surface is formed in strong alkaline condition. With the increase of the collector concentration, the contact angles of the collophanite and the dolomite all first increase then decrease. The formation of hydrophilic micelles results in the decreasing of contact angles and enhancement of surface hydrophilicity opposite when the collector concentration exceeds CMC. The contact angles of the collophanite and dolomite and the WSG of the bubble adhesion increase, the hydrophobicity enhance with the increasing of carbon chains of saturated fatty acid from 12 to 18. The variation tendency for the adsorption quantity of collectors and floatability of collophanite and dolomite are in line with the change trend of contact angle basically. It shows that the wettability of solid-liquid-gas interface can be well characterized by the dynamic captive-bubble technique.INTRODUCTIONPhosphorite resources are the main raw material for producing phosphate fertilizer and producing phosphoric acid (Cao et al.,2005), which is an important strategic mineral resource. The useful minerals in calcareous-magnesium phosphate ore are collophanite, and the main gangue minerals are dolomite (SISH et al.,2003). The lattice ions of the phosphorite and dolomite are both Ca2+, their similar surface properties and similar floatability are the main reason for the flotation of calcareous-magnesium phosphate ore difficultly (Fang et al.,2011). Usually, fatty acid collectors are used for the flotation of calcareous-magnesium phosphate ore under acidic conditions by reversing flotation method to remove dolomite (ABOUZEID et al.,2009), or direct flotation is used to gather collophanite in the alkaline conditions (Gong et al.,2017). The flotation behavior of collophanite and dolomite affects the indexes of concentrate and flotation efficiency directly. Therefore, it is necessary to study the action mechanism and the flotation method of the collector with the phosphate rock and dolomite respectively (Moudgil et al.,1988; Hanna, et al.,1990)."

Jan 1, 2018

This paper will examine the prospects for Queensland's non-fuel mineral industries as we approach the 21st century. The opportunity for growth is unprecedented. Exploitation of recent discoveries, proposals and developments in downstream processing are predicted to contribute to a doubling of the State's mineral exports to around $10 billion by the year 2000. In 1995 - 96 the value of Queensland's mineral production was $6 billion, comprising $1892 million metallic minerals, $127 million non-metallic minerals and $4 025 million total fuel minerals. For many years Queensland has been among the world's major producers of copper, silver, lead, zinc, bauxite and mineral sands. Recently Queensland has become an important producer of magnesia. Queensland's ability to compete results from its location close to rapidly developing Asian markets, the diversity of its major minerals and an increasing ability to add value to the resources base using competitively priced energy. Northwest Queensland is one of the richest base metal provinces on earth following the recent discovery of five world-class orebodies. Of these deposits, Osborne (copper-gold) has commenced production and Cannington (silver-lead-zinc) and Ernest Henry (copper-gold) are scheduled to be developed by 1997. Century Zinc Limited and the Queensland Government are negotiating with native title claimants on the development of Century (zinc-lead-silver). Expansion is in progress at the Mount Isa copper mine (renamed the Enterprise) and copper smelter and a high analysis fertiliser project may be developed based on Phosphate Hill. Korea Zinc Company Limited has reached agreement to construct and operate a 350 000 Mtpa zinc smelter/refinery near Townsville. There are future expansion prospects for the vertically integrated major industrial mineral operations based on Weipa bauxite and Kunwarara magnesite. Upgrading of the Boyne Island aluminium smelter will require a doubling of alumina consumption. Downstream processing options for Kunwarara magnesite are being investigated and are expected to lead to increases in production and the manufacture of a range of value-added products. At the Yabulu refinery near Townsville, nickel and cobalt production using imported ore is to be increased and a commercial cobalt plant is to be built. Additional opportunities for further processing and manufacturing are associated with proposed new mines at Ely (bauxite), Skardon River (kaolin) and Goondicum (ilmenite). Recently discovered resources of zeolite and perlite also offer exciting development possibilities. Other manufacturing opportunities such as glass and ceramics based on local and plentiful clay and silica sand could replace imports. Silica sand at Cape Flattery is currently exported and production is expected to double.

Jan 1, 1997

By G. Kim

The influence of bacterial growth phase on the flotation behavior of malachite has been investigated in a well-controlled Hallimond tube system. The microflotation tests were conducted for malachite (45?53 µm) using different amounts (bulk phase concentration=1×108?5×109 cells/mL) of Rhodococcus opacus (R. opacus) as a collector, which was grown at mid-exponential versus stationary phase, at a constant speed (340 rpm), pH (6), and malachite-bacteria interaction and flotation time (each 10 min). Hug differences between R. opacus cells in mid-exponential and stationary phase was observed from the results for electrophoretic mobility and flotation tests. Specifically, the isoelectric point of the cells in the stationary phase was lower than that in the mid-exponential phase, suggesting that the amount and distribution of surface functional groups onto cell surfaces are likely different. Additionally, the cells in stationary phase led to significant increase in the flotability compared to those in mid-exponential phase over the background bacterial concentration level of 1×108?5×109 cells/mL. Furthermore, the flotation efficiency tended to increase with increasing cell dosage for stationary phase cells while no distinct difference was observed for mid-exponential cells.

Feb 27, 2013

By T. M. Barczak, Zach Agioutantis

The Support Technology Optimization Program (STOP) has been developed by the National Institute of Occupational Safety and Health (NIOSH) to provide a comprehensive tool for evaluating the performance of available secondary roof support systems and designs based on support strength, convergence, cost, installation time and material handling considerations. This program uses engineering models developed from full-scale testing of numerous supports under controlled loading conditions in the unique NIOSH Mine Roof Simulator load frame to determine the support load-displacement performance as a function of the various sup- port design parameters. Both standing supports, such as wood cribs installed within the entry, and intrinsic supports such as cable bolts, can be evaluated. Support systems can be designed and compared for use in a new mining section or to evaluate potential replacements for an existing design. The support design requirements are defined from 1) estimating the failure height in the immediate roof, 2) in-mine measure- ments of support and strata interaction or development of ground reaction curves from numerical modeling, 3) the performance of an existing support system, or 4) from any arbitrary load and convergence criteria. All settings can be saved to permit resuming an evaluation in progress at a later time. This paper presents the updated MS Windows version of this tool, which can be easily installed and run on a personal computer. This Windows implementation will feature a project and application scenario setup where multiple scenarios can be assigned to one project. Scenarios can then be compared on support parameters and cost. Cost parameters can be provided either as individual cost items or using a price grouping feature. Additional support performance curves and/or additional ground reaction curves will be distributed with program updates as new information is developed. Users can also provide their own support and/or ground reaction curves.

Jun 25, 2024

By William H. Pomroy, Shail J. Butani

"This Bureau of Mines publication presents a statistical analysis of official U.S. Mine Safety and Health Administration (MSHA) metal and nonmetal mine fire reports from 1950 through 1984, plus accounts of selected nonreportable fires (less than 30 min and no injury) and opinion data on fire hazards from mine safety directors. Fires were analyzed by time trends, ore type, ignition source, burning substance, location in mine, equipment involved, means of detection, duration, number of injuries and fatalities, mining method, and successful extinguishing agent. The leading ignition sources were electricity in underground fires and engine heat in reported surface fires. The most frequent burning substance was combustible liquids for all nonreportable fires, reported surface fires, and reported underground fires from 1978 to 1984. For underground fires reported prior to 1978, timber was the leading burning substance. Mobile equipment was the type most frequently involved in both underground and surface fires. Underground fires occurred most often in haulageway or drift areas, and reported surface fires occurred most often in plant and mill buildings, while most nonreportable surface fires occurred in other areas. The most common methods of extinguishment were water hose lines for reported fires and dry chemical handportable extinguishers for nonreportable fires. INTRODUCTIONIn support of the Bureau of Mines research on mine fire protection, two separate baseline studies on mine fire incidents have been prepared. The first study addressed coal mine fires. The results of that study are summarized in the Bureau's Information Circular 8830, ""A Statistical Analysis of Coal Mine Fire Incidents in the United States From 1950 to 1977."" This second report, addressing metal and nonmetal mine fires, is the companion to IC 8830. Together, these two reports provide a comprehensive, factual summary of the mining industry's fire experience.This report, like IC 8830, covers (1) MSHA fire incident reports, (2) records of nonreportable fires (less than 30 min and no injury), and (3) mine safety directors' opinions on fire hazards. The MSHA fire reports provide the most reliable, objective, and accurate historcial record of the major noncoal mine fires that occurred during the study period (1950 through 1984). However, MSHA fire reports alone understate the true magnitude of the fire problem because metal and nonmetal mines have been legally required to report fires to MSHA only since 1968. Although some fires were reported prior to 1968, doubtless a great many were not. Also, the reporting regulations that took effect in 1968 specify that only fires lasting 30 min or longer or involving an injury need to be reported. MSHA fire reports are thus limited in scope by MSHA's legal authority. In order to provide a more comprehensive data base, it was also necessary to gather and analyze mine company records of nonreportable fires."

Jan 1, 1986

Professional engineers of today require a wide array of experience and knowledge. It is true that commonly engineering degrees do teach the technical requirements well, but do fall short in the way of teaching other non-technical issues of professionalism to the student. Today calls for an engineer who does not only have a high standard of the technical knowledge required for their degree, but also has a broad range of experience in areas that are becoming increasingly important in engineering. The importance of social responsibility, liability and interpersonal relations is high. Through the face of the changing world, it has become clear that there is a need for a new type of engineer, who has a broad range of expertise, as well as the typical technical abilities required. This paper will outline these non-technical issues and propose ways of combining these ideas into the mainstream engineering degree.

Jan 1, 2004

By Ralbern H. Murray

Typical First Year Selling Price Strip Mined Western Sub-Bituminous Coal Based [Fixed Capital (1) $600 MM Construction Loan Interest $100 Working Capital $ 30 Start-up Costs $ 30 Total Capital Requirement $760 MM Annual Costs (First Year) $M/Year Coal (2) 443,550 Operating Costs(3) 53,000 Depreciation(4) 36,500 Interest(5) 45,220 After Tax Profit(6) 34, 200 Federal Income Tax (48% Rate) 31, 570 Gross Revenue Required 245,040 (Less) By-Product Sales (18, 000) Net Revenue Required 227, 040]

Jan 1, 1975

By Juliana Cecília Costa Ribeiro Vieira

As operações de amostragem de qualquer atividade que necessite de controle de qualidade são fundamentais tanto para fins de garantia da qualidade quanto para efeito comercial dos produtos. Na mineração de ferro não é diferente. Uma amostragem que carregue um vício de 0,20% no teor de Fe (%) pode representar uma perda de faturamento de aproximadamente US$226 mil para cada milhão de toneladas comercializadas aos preços atuais. Para fazer um bom plano de amostragem é necessário conhecer o grau de heterogeneidade ou variação de qualidade (sW) do minério a ser amostrado. Segundo Pierre Maurice Gy, um dos mais renomados especialistas em amostragem de minérios em geral, a forma mais indicada para estimar a sW é o método do variograma. Neste trabalho usamos a metodologia do variograma, com base na Norma Técnica ABNT ISO 3084:2003, para estimar a sW do minério tipo Sinter Feed produzido na Mina de Serra Azul da ArcelorMittal.

Oct 30, 2017

By Robert S. Warfield

The Federal Bureau of mines and U.S. Geological Survey conducted exploratory investigations and geologic mapping in the Wishbone Hill district of the Matanuska coalfield almost continuously from 1942 through 1958. These investigations delineated reserves of high-volatile bituminous coal necessary to supply the rapidly expanding military and civilian requirements in the Anchorage area. This report describes the program conducted by the Bureau of Mines from 1949 through 1958, and briefly summarizes previous investigations, the results of which have already been published. The coal-bearing structure on both the north and south limbs of the prominent Wishbone Hill syncline was explored by 8,719 feet of churn drilling and 25,460 feet of diamond-core drilling. A total of 33 holes were drilled ranging in depth from 60 to 2,114 feet. To supplement the drilling operations, bulldozer and dragline trenching were undertaken at key locations; about 25,000 cubic yards of dragline trench were excavated in the vicinity of the old Premier mine.

Jan 1, 1962

By M. Rahmanpour

"Mine planning is a multidisciplinary procedure that aims to guarantee the profitability of a mining operation in changing and uncertain conditions. Mine plans are normally classified as long-term, intermediate-term, and short-term plans, and many factors affect the preciseness of these plans and cause deviations in reaching the objectives. Commodity price is the heart of mine planning, but it has a changing and uncertain nature. Therefore, the determination of mine plans in the presence of uncertain mineral price is a challenge. A robust mine plan reduces the risk of early mine closure. A procedure is presented to determine the value at risk (VaR) in any possible mine planning alternative. VaR is considered together with downside risk and upside potential in order to select the most profitable and least risky plan. The model is tested on a small iron ore deposit. IntroductionMining projects are normally evaluated with the objective of maximizing economic value, as measured by the net present value (NPV). The aim of mine planning is to develop a yearly extraction plan that guides the mining operation to the highest NPV (Dagdelen, 2007; Yarmuch and Ortiz, 2011). This plan considers the technical constraints such as blending requirements, block sequencing, and pit slope (Caccetta and Hill 2003). Thus, the mine plan affects the economics and the payback period of mining operations.Mine planning is a procedure based on which the profitability of the mining operation is guaranteed in changing and uncertain conditions (McCarter, 1992). However, conventional mine planning ignores the volatility and uncertainty of future commodity prices and does not allow for managerial flexibility. It is common practice to assume a deterministic and constant commodity price through the mine life. The problem with this approach is that the commodity price is the heart of the mine planning procedure and governs the profitability and feasibility of the operation; thus ignoring price volatility will result in a sub-optimal mine plan."

Jan 1, 2016

By E. P. Youngman

The law of June 5, 1911, suplements and amends the Laws of April 21, 1810 (the basic law) and May 2, 1837. The Royal Decree of September 15, 1919, coordinates the provisions of the Law of June 5, 1911, with those of the Laws of April 21, 1810, of May 2, 1837, and of July 8, 1865, that have remained in force, as well as with certain articles of the Law of September 1, 1913, which revisad the system of taxation. The revised code has been brought together in one volume.3 All citations in this abstract refer to the coordinating Royal Decree of September 15, 1919, unless it is otherwise specifically indicated.

May 1, 1930

By D. R. Hack

Increased consumption of concrete in the Pacific Northwest has pushed aggregate resource development pressure from urban areas west of the Cascade Range to rural areas east of the Cascades. Some recent development has focused on barge and rail accessible off-reservation Indian allotments that are exempt from state and county regulations. These lands have their own unique set of challenges, especially when Federal and Tribal governments have conflicting goals and attitudes pertaining to resource development. This paper discusses issues of leasing, reclamation, Federal vs. Tribal authority, cultural resources, and the history of allotment.

Jan 1, 2002

By Launa G. Mallett, Jr. Brnich

Overview: The first step to emergency preparedness and maintaining a safe workplace is defining and analyzing hazards. Although all hazards should be addressed, resource limitations usually do not allow this to happen at one time. Risk assessment can be used to establish priorities so that the most dangerous situations are addressed first and those least likely to occur and least likely to cause major problems can be considered later. Purpose: This training package was developed to assist instructors as they (1) determine how to use risk assessment to improve safety preparedness and (2) present risk assessment concepts and tools to trainees. The concepts and tools presented here can be applied to any mine hazard.

Jul 1, 2003

By R. J. R. Cornelissen

The elimination of the incidence of silicosis in employees in industries such as mining and pottery is an ongoing international initiative. After many decades of industrial activity in these industries and many dollars spent on preventative measures, silicosis is still occurring. The exposure-prevention measures taken so far have certainly improved the working environment dust concentrations; however, the illness is still regularly diagnosed in workers. More funding is needed for interventions to improve working conditions. Many aspects of dust prevention and suppression will be researched and exposure assessment methodologies and equipment will need to be reviewed for the purposes of improvements in effectiveness. This paper presents results from laboratory tests carried out on gravimetric sampling pumps and cyclones. It highlights the erratic flow produced by gravimetric pumps of three different manufacturers who claim their respective pumps are equipped with flow stabilisers. The standard BS EN 1232:1997 is used as a basis for the tests. A method, albeit impractical for fieldwork, is shown for the elimination of the pulsation in the flow. This method serves to prove the method and protocol used in this study. The pressure loss caused air-flow resistance of cyclones is measured. The air inlet aperture size of cyclones is measured. The large discrepancy in the two criteria between individual cyclones is shown. The paper concludes that all the pumps tested failed the prescribed limits of BS EN 1232:1997 regarding the pulsation of the gravimetric sampling flow. The difference in flow characteristics of the cyclones, together with the erratic flow produced by the pumps, throws into question the accuracy of the exposure assessments. It is suggested that substantial resources be channelled towards solving these flow problems in parallel with measures taken to reduce exposure. In principle, the accurate assessment of exposure and dust concentration levels is a prerequisite for effective management of the problem of silicosis.

Jan 1, 2009

By Ghassan Skybey

Australian coal mines uses state of the art technology in coal rib reinforcement. This paper highlights the development over the past 15 years in coal rib support technology, along with the advantages and disadvantages of each system. It also outlines the current trend in using coal rib reinforcement in speeding up the dowels installation to improve the current low drivage rate. An innovative cuttable dowel is discussed which improves the drivage rate. This new dowel is self anchoring it uses no resin anchor it has a 5 tonnes (5.51 tons) anchor capacity and can be fully installed in approximately 10 seconds.

Jan 1, 1995

By F. Louis Grammer

The following study of flue-dirt and the influences controlling it may be interesting to many. It is published because it represents observations at about thirty furnaces at different times. It may assist in giving an impetus to the making of similar observations elsewhere. Until ten years ago, the metallic waste in furnace-gases was not considered a problem of pressing urgency in iron metallurgy—certainly not in the blastfurnace end of it. Many plants at present ignore, or pay but little attention to, top-pressures. Prior to the introduction of Mesabi ore, the losses in escaping gases, if considered at all, were regarded as thermal losses, or losses of fuel (except by those interested in lead, zinc, silver, etc.). In a high-priced material like ferro-manganese, such losses were, indeed, considered important. But the behavior of the Mesabi ores, corning, as they did, in practically inexhaustible quantities, could not be disregarded by the furnaceman. These ores came to stay. The tables appended below have purposely been altered to disguise the plant, the company and the ores used. The comparative values are maintained. In these tables, the influencing elements and conditions which are constant, or practically so, namely, size of furnace, quantity of wind, fuel used, etc., are not mentioned. The figures represent observations consistently followed up for a long period. The weights of flue-dirt were obtained from cars on which no other dirt was thrown. The analyses and calculations are based on the best of sampling. The effects of slips are excluded. Slips should not occur at well-regulated or properly-constructed furnaces, excepting under unusual and rare conditions. Allowances are made for moisture, scrap charged and silicon in the metal. The cutting effect of Mesabi

Jan 1, 1904

By J. O. Marsden

The Candelaria copper-gold mine is located approximately 25 km south and east of Copiapo in Region III, Chile. The original concentrator was designed to treat 28,000 t/d (30,800 stpd) of chalcopyrite-bearing ore through a circuit consisting of a single 11.0 m (36 ft) diameter SAG mill, two ball mills, conventional rougher and scavenger flotation, column cell cleaner flotation, and ceramic disc filtration. The plant was commissioned in August 1994 and quickly reached capacity and expected levels of metallurgical performance. In May 1996, a decision was made to double the capacity of the concentrator by the addition of a second line of equipment. The expanded facilities were commissioned in October 1997, less than 18 months after the decision to proceed, and well within the budget. The original concentrator facilities were replicated or duplicated as much as possible, however, a number of important equipment changes were made to take advantage of industry developments since the original concentrator was designed. These included the use of Eimco 120 m3 (4,200 ft3) cells for rougher and scavenger flotation and the installation of a Svedala VTM -800 Vertimill for regrinding. This paper describes the rationale behind these changes and explores the reasons for the success of the project.

Jan 1, 1999

By Martin Stoklossa

Surface mining operations typically require run-of-mine material to be sized for further processing. In-pit crushing facilities serve this need, as stationary, semi-mobile or fully mobile units. Although in particular fully mobile crushing facilities have been in use for over half of a century, other surface mining techniques have typically been implemented. However, with increasing operating costs in truck and shovel operations, and other economic considerations, mobile crushing plants are increasingly a viable option. The operational and economical parameters in relation to the optimal surface mining equipment selection will be reviewed. The role of the mobile crushing technology within the continuous vs. noncontinuous surface mining operation and basis for mine planning are also discussed. Current applications and respective case studies will be reviewed. Key performance indicators will be presented. These performance parameters can be viewed as a tool to aid in the equipment selection process. The future direction for further research and development in mobile crushing facilities will also be presented.

May 1, 2008