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By P Tobar

The development plan (long-term plan) of El Teniente Mine, Codelco-Chile, includes 100 per cent primary ore, located at increasing depths, which may involve several difficulties related to the application of the current panel caving method, such as a high seismicity level, a coarse fragmentation and ore pass damage. Therefore, it is a strategic priority for the El Teniente mine, to design and to test alternative mining methods, at similar or lower costs to ensure an efficient and safe ore extraction. In this context, the Macrotrench method is developed, as a competitive alternative to the current method. The document describes the panel caving method, the experience achieved in the primary ore exploitation from the geomechanical point of view. It also describes the æmacrotrenchÆ method as an alternative to the current exploitation method. Finally, the comparative advantages of macrotrench in relation to panel caving are presented. The results obtained during the engineering stage include the following aspects:the mining design, the material handling, a geomechanical evaluation of the method, and a comparative analysis.

Jan 1, 2000

By John Johnston

THIS necessarily brief sketch will attempt to summarize the high lights of perhaps the best meeting so far held by the Iron and Steel Division. All sessions were well attended and the discussion was vigorous and of a high order. The technical sessions opened. on Tuesday morning. "Precipitation Hardening of Copper Steels" was discussed by Cyril S. Smith and Earl W. Palmer, and dealt with steel with a 1 per cent copper content. Discussion brought out that there were no fabricating difficulties, but that the surface might be somewhat checked due to intergranular penetration of copper which could be easily taken care of. Probable advantages of steels of this type for high temperatures were pointed out. "An Improved Nickel-chromium Hardened Chilled Cast Iron," by J. S. Vanick, described a wear-resistant cast iron and evoked a lively discussion.

Jan 1, 1933

By Martino Scialpi, Miriam Piemontese, Claudio Cimiotti, Matt Kendall, Nicholas Karlin, Roberto Schuerch

The Los Angeles, California JWPCP effluent outfall tunnel will transport secondary-treated effluent from the Joint Water Pollution Control Plant in Carson to the White Point Manifold. Upon completion, through ground conditions ranging from soils to hard rock, the tunnel will be approx. 7 miles (11 km) long with a finished internal diameter of 18-ft (5.5 m). This paper will present the Tunneling Condition Assessment Report (TCAR) and Tunnel Operation Plan (TOP) developed prior to construction, as well as the actual TBM performances achieved along the northern portion of the alignment in soft ground, shallow cover, and beneath a densely urbanized area.

Jun 23, 2024

By Hans Ruge

The El Soldado copper mineralization occurs as relatively high-grade irregular ore bodies with assay contacts and with frequent inclusions of barren rock. The sampling method must be timely for production grade control purposes, as well as accurate and inexpensive. Sampling techniques evolved from sampling dump cars at the haulage level to sampling scooptrams at the loading pockets. These were abandoned in favor of sampling production blast holes. Several sampling alternatives are discussed. These involve the selection of optimum volumes and sampling frequencies while taking into consideration geological parameters and statistical analyses of sampling data.

Jan 1, 1984

By S. Hoerger

Newmont has a large integrated operation in Northern Nevada with numerous mines, stockpiles, and processing facilities. There are over ninety defined metallurgical ore types and over sixty defined gold recovery process options. To take better advantage of the available synergies, a complete Nevada wide mine plan and process model along with a mixed Integer and Linear Programming optimization tool has been developed and implemented. This system is maintained and operated by a Nevada Planning Group. Standard in-house planning software tools and methods have been implemented at all mine sites. While increasing the effectiveness of planning in Nevada, these changes have allowed a significant reduction in overall Mine Engineering staff.

Jan 1, 1999

By Percy Barbour

The town of Goldfield, Nevada, with the exception of six stone buildings, was burned to the ground to-day. One man is dead from causes attributed to the fire. A woman is missing and is believed to have perished and several persons were treated for burns as the result of the conflagration believed to have been of incendiary origin which started in the old Tenderloin District. The water supply was not sufficient and dynamite only scattered the frame structures and added kindling to the flames which were fanned by a forty-mile wind. Newspaper Dispatch, July 6. No former Goldfield resident could read that dispatch with unmixed feelings. About two o'clock one morning the crowded train from San Francisco landed me in Goldfield no more hours late than it habitually was. The desert air was clear and crisp and bracing but the pandemonium of cab and bus drivers did not drown out the sounds of music and merriment which floated from the blaze of light which was Goldfield about three-quarters of a mile from the station. As I stood in the ferry house, at the foot of Market Street, awaiting the Oakland Ferry, an old friend of mine, down to see who was departing for the greatest boom town of this generation, informed me that if I had made no reservation for quarters in Goldfield, I would be unable to obtain any, even chairs in the hotel lobbies were renting for $4 per night, and volun-teered the use of his room there for my convenience until his return. He described the house and location, which I identified without difficulty, but found no one to direct me to the room. I peered through a glass door into a room which seemed to be unoccupied and timorously entered and turned on the electric light., I found mail on the dresser addressed to my friend,

Jan 8, 1923

By S. Minamiguchi

Grain refinement is effective to enhance strength and ductility of metallic materials. However this advantage has not been utilized fully for magnesium alloys in industry because microstructure control through thermomechanical treatment is difficult owing to their poor deformability. The authors proposed a high-speed heavy-reduction rolling for production of Mg alloy sheets. It was found that the deformability is significantly improved at high speed and that the thickness can be reduced 60% by one-pass operation even at room temperature without fracture at the rolling speed higher than 1000 m/min. In this study, commercial AZ31B sheets were rolled at 2000 m/min between room temperature and 350°C, and quenched immediately after the rolling. The sheets rolled at 200°C show the finest recrystallized microstructure with the mean grain size of 2.2 Rm. They show outstanding mechanical properties with the tensile strength of 293 MPa, and the elongation of 25%. It is concluded that high-speed rolling is very advantageous for grain refinement and improvement in mechanical properties as well as deformability and productivity.

Jan 1, 2006

By Thomas S. Nye

Mineral exploration in the United States relies heavily on theoretical geologic concepts and indirect methods such as geophysics and geochemical prospecting, as there are few exposed areas of mineralization which have not already been explored at least once. In Mexico ore-grade samples can be cut at the surface on vein, replacement, and disseminated types of deposits in many areas. Here the problem is not in finding a mineralized area but in deciding which mineralized area can be explored and developed at the least risk and cost, and have the greatest profit potential, within the framework of Mexican mineral economics and government policies. Mexico's min¬eral industry is regulated through a system of permits for various phases of mineral exploitation, and by taxes. This regulation and its effects are not unlike those which may be expected in the United States if present legislative and administrative trends continue.

Jan 1, 1972

By A. J. Basu

New technologies, such as computer based learning, wireless computing, internet2, online courses, distance learning, and in general multimedia applications are being implemented in the higher education sector in an increasing manner. However, these implementations are not coherent, and lack standards. However, one example of the existing standards is the development and implementation of the virtual learning environments. These technology tools help in delivering the eLearning objectives. There is a major initiative in Europe (eEurope action plan) in promoting eLearning towards creating a knowledge-based society. Technology implementation is the major driver for achieving the eLearning objectives. A two-year pilot project on implementing technology tools including virtual learning environment (VLE), video-conferencing, and simulation and visualization was carried out for providing a blended learning environment for undergraduate and graduate students in Mining Engineering (undergraduate) and Mineral Deposit Evaluation (M.Sc.) course at the Imperial College London. The pilot project was funded by the Imperial College Centre for Educational Development (ICCED). The project did contribute towards activities for creating an institute-wide eLearning strategy in line with the eEurope action plan.

Jan 1, 2003

By N. Henderson, J. Weyer, J. F. Brune

"The mining industry worldwide is currently facing a significant restructuring process. In most underground mines, widespread mechanization of the mining processes increases production while reducing staff numbers. At the same time, mining depths as well as the lateral spread of the mine workings are increasing. This ever-changing mining environment requires sophisticated solutions for the design and operation of underground mines. In fact, a reduced number of mining engineers is taking responsibility for everincreasing mine operations. This applies not only to the excavation of the minerals, but also to all other aspects of the mining operation, including health and safety, disaster management, and mine rescue organization.Most mining engineering graduates entering the industry lack experience in mine emergency management. Young engineer trainees must learn mine emergency management and rescue work in addition to their normal training experience on the job. Often, and unfortunately, emergency and rescue training at different mining companies is not carried out to the highest level and standard and with the best possible training outcomes. The tasks and challenges a young engineer faces while being trained in a new position do not leave much room for additional training in mine rescue and emergency management. At the same time, experienced, ’old hands’ are retiring and cannot easily be replaced due to limited graduation numbers.Strategies are being developed at mining universities worldwide to train mining engineering students in handling mine emergency situations and to provide hands-on experience for managing potential accident and disaster scenarios underground. Two of these strategies, from the USA and from Central Europe, are presented in this paper. These specific strategies have to be seen under special consideration of the local and regional boundary conditions, but might serve as case studies for mining schools and universities in other countries."

Jan 1, 2014

By M. Mustafa Kahraman, Sean Dessureault, W. Pratt Rogers

Most contemporary mines have considerable amounts of data. Structured and unstructured large data sets are colloquially named big data. Much of the data in mining operations come from a variety of systems, each with different databases and reporting environments. Standard technology deployments create a Bsilo-ification^ of data leading to poor system benefit. Through modern server monitoring and systematic approach, data utilization and value can quantifiably be measured. The Data Utilization and Value Index (DUVI) can quantify business intelligence best practices and user interaction. This study seeks to provide a data management tool to measure data utilization across the process of converting data into action.

By M. Murillo, J. Botín

"Mining has always played a key role in the improvement of the quality of life, but also, it has been a source of environmental and social conflict. Despite the great progress in social responsibility and sustainability experienced in recent decades, the public image of mining remains low and mining projects and operations must face growing difficulties and demands, which results in increasing capital and operating costs. In practice, the objective of a mining company is to create value for its shareholders and therefore, the best approach to Sustainability would be to foster those drivers aligning sustainability and shareholders value, this is, the “Business Case for Sustainability” (BCS). Only under this assumption, convergence of corporate strategy and sustainability may be assured. This paper discusses partial results of a Research Project being carried out at the Catholic University of Chile, aiming to develop a social and economic model for the effective integration of the values of sustainable development in the strategy of mining companies and their stakeholders. INTRODUCTION Mining is fundamental for the wellbeing of our everyday life. But as important as these benefits are for humanity, the mining Industry has had negative environmental and social impacts. For these reasons, a closer relationship between “Sustainable Development and Mining” is more necessary than ever. The Brundtland definition of Sustainable development does not have a clear relationship with mining, but it provides the context. Under a strict interpretation of the Bruntlandt definition, stating that “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs” [10], mining would not be sustainable because the minerals are non-renewable resources. However, this research focuses on how mining can contribute to the sustainable development in the territories where the projects take place. In other words, this research follows the publication titled “Berlin II Guidelines for Mining and Sustainable Development” [9], which stated that “A mining project that is developed, operated and closed in an environmentally and socially acceptable manner could contribute to sustainable development. Critical to this goal is ensuring that benefits of the project are employed to develop the region in a way that will survive long after the mine is closed”. The potential conflicts between mining stakeholders arises from the interpretation of the concept “developing, operating and closing a project in an environmentally and socially acceptable manner”, and the impact on the economic objectives of mining companies. Nevertheless, the ability of mining companies to control new demands and expectations of stakeholders has threatened the implementation and continuity of their projects and operations. To deal with these issues this research analyses the “Business Case for Sustainability” (BCS). It refers to the process leading to a business and social-economic environment whereby shareholders value may only be optimum under a business strategy which fully integrates the values of sustainability. In the model proposed, the Business Case will start when the benefits are higher than the costs. Benefits not only associated with efficient use of resources, also benefits associated with avoiding difficulties to continue with the mining projects such as strikes, heavy penalties, loss of investment, and so on."

Jan 1, 2016

By O. J. R. Baena

Mining activity in the Segovia region in NE Colombia is the main source of employment in the local economy. This has created major problems of illegality and informality mining associated with a high social and environmental impact, as inefficient technologies are used and high consumption of toxic substances required in the process of gold recovery by amalgamation and cyanidation. In this work is presented mineralogical characterization of six local mills and studied beneficiation processes developed in them. With the results presented a proposed plant design that eliminates the use of mercury by replacing gravity concentration processes taking advantage of the characteristics of the treated material. Significant results were obtained regarding the recovery of precious metals and present a methodology that can be replicated in other mineral beneficiation plants that use gold amalgamation processes. This implies a significant reduction in mercury use and decreased risk of human contamination associated with this.

Feb 23, 2014

By Mike Smith, George Chung

"A 23 million dollar Flotation Plant has been commissioned at the Iron Ore Company of Canada in 1998. Nine OK-50 cells &re used to float silica in this 1,400 tomes per hour plant. The paper details project development, construction and operating results. This plant gives IOC the capability to produce not only high quality blast furnace pellets of varying silica, CaO and MgO levels, but also a high iron, DR grade pellet. The first activity was simply to sit down with the suppliers, Outokumpu, Wemco. GL&V and Svedala, to discuss applications and share experiences. We learnt what each supplier had to offer, what features would particularly suit this application, what options were offered, what were the materials of construction, how the equipment is maintained, which wear parts require replacement, etc., etc. We tried to learn as much about the equipment as the suppliers themselves knew. Then we tried to learn more: we contacted users and asked about any weak points, which options were worth incorporating and which items were not. We then discussed these points with the suppliers and established how potential problems might be overcome."

Jan 1, 1999

By K. C. Dean

The Bureau of Mines, following passage of the Solid Waste Disposal Act of 1965, was authorized to conduct research on methods for utilizing, stabilizing, or reclaiming mineral wastes. This report summarizes laboratory research conducted by the Bureau and cooperative field studies made with the mineral industry to reduce the environmental impacts of air and water pollution deriving from mineral wastes. Utilization research showed that both dry-press and steam-cured building bricks and ceramic tile could be made from copper mill tailings and other discarded mineral wastes. Sponge iron was produced from steel mill and amination industry wastes, and valuable mineral products were extracted from such diverse sources as flue dusts and uranium tailings. Mineral wastes were combined with agricultural and/or sewage wastes to make artificial soils that have the potential of resolving several disposal problems by production of a useful commodity. Physical, chemical, and vegetative stabilization methods were evaluated, singly and in combination, for reclamation potential on copper, uranium, lead-zinc, and asbestos tailings. Suitable methods were developed in the laboratory for overcoming major adverse conditions of these wastes such as salinity, heavy metal toxicity, acidity, basicity, lack of nutrients and organics, and unstable surfaces. Field testing of these methods was performed on a variety of mineral wastes. Costs for the various stabilization and utilization-procedures developed were also determined.

Jan 1, 1986

By S. Vorberg, J. Preussner, B. Fischer, U. Glatzel, R. Völkl, M. Wenderoth

Pt-Al-X alloys have shown good mechanical properties and adequate oxidation resistance. Starting from a promising Pt-Al-Cr alloy, the influence of Ni additions was investigated. After ageing finely dispersed precipitates are observed. Nb, Ta, Ti and Re increase strength when added as partial substitute for Al. Minor additions of B increase creep resistance and rupture time remarkably, owing to strengthening of the grain boundaries. The evolution of the alloy development programme as well as selected properties of the multi-component Pt-base alloys are presented.

Jan 1, 2006

By J. H. Polhems, R. B. Brackin, D. B. Grove

THE heavy media separation process plays an outstanding role in the concentration of 4000 tons of zinc ore per day at the Mascot mill of the American Zinc Co. of Tennessee. Of the total tonnage, 72 pct is treated in the heavy media separation plant to reject 56 pct of the ore as a coarse tailing, which has a ready market. Concentrates from this separation are beneficiated further by jigging and flotation. Approximately 25 pct of the total zinc concentrate production is made in the jig mill. Jig tailings are ground and pumped to the flotation circuit where the balance of the production is made. Fig. 1 shows a generalized flowsheet of the mill. The Mascot ore is a lead-free, honey-colored sphalerite in dolomitic limestone, with lesser amounts of chert and some pyrite. A mineralogical analysis is given in Table I. After 10 years of successful operation with galena medium and treatment of nearly 10,000,000 tons of ore, a decision to convert to ferrosilicon was made early in 1948 because of the increasing price of galena and consequent high operating costs. The conversion was made on Nov. 6, 1948, and the results obtained since that time have shown remarkable improvement over those made with galena. The Table I. Mineralogical Analysis of Mill Feed, Pct Calcium carbonate 49.5 Magnesium carbonate 35.2 Iron oxide and aluminum oxide 1.5 Zinc sulphide 4.5 Insoluble 9.3 100.0 Table II. Comparative Data, Galena and Ferrosilicon Ferro- Diner-Gelenaa siliconb ence Operating costs per ton milled, ct. 21.21 9.12 12.09 Medium consumption per ton milled, lb 0.80c 0.15 0.65 Reagent consumption per ton milled, lb 0.45 0.02 0.43 Tailing assay, pct Zn 0.310 0.297 0.013 Concentrate. oct Zn 12.08 10.33 1.75 Heavy medla ieparatlon recovery. pct 89.38 90.22 0.84 Mill feed rate, tons per hr 153 166 13 Heavy mesa separation feed rate. tons per hr 100 10 0 Tons milled per heavy media separation man shift 350 620 270 Mill feed to coarse tailings, pct 51.0 56.7 5.7 Lost mill time, pct 5.6 5.0 0.6 Power consumption, kw-hr per ton 2.06 1.92 0.14 a 1947. " First 6 months of 1950. c Net consumption after deducting credit for reclaimed waste galena. Consumption of new galena was 1.320 lb per ton milled. For entire life of galena operation, a credit of 40 pct of the value of the new galena added was realized from the sale of waste galena. comparisons given in this report cover the first 6 months of 1950 as representing the ferrosilicon operation, and the year 1947 as representing the galena operation. This was the last full year in which galena was used exclusively and is representative of the best work done during the 10 years of operation with this medium. After only 2 years' operating experience, with ferrosilicon and treatment of 1,807,585 tons many advantages have been revealed and are summarized in Table 11. Development Prior to the introduction of the heavy media process, all the mill feed was crushed through 5/8 in. and treated by jigging. A finished tailing assaying 0.66 pct Zn was made on rougher bull jigs, and cleaner jig tailings were ground for treatment by flotation. The first test work on the sink-and-float method of mineral beneficiation was carried out at Mascot in 1935, using a 3-ft cone and galena medium for batch tests. The following year a 6-ft cone was installed for pilot-plant work. This unit became a part of the mill circuit on March 1, 1936, and handled a gradually increasing tonnage in the next 2 years as the process developed to the point where it could treat all the + 3/8-in. material in the mill feed. Coarse jigging was then discontinued on March 1, 1939, and all coarse tailings have been made by the heavy media separation plant since that time. Feed Preparation: The original feed preparation plant consisted of a drag washer followed by two 4x10-ft Allis-Chalmers washing screens. A surge bin and two additional 5x12-ft AC washing screens were added in 1943. Use of primary and secondary washing screens was found essential to provide the cleanest possible feed for the cone and thereby avoid excessive contamination of the galena medium. Improved washing was obtained by replacing the drag washer with a 7x20-ft Allis-Chalmers scrubber, shown in Fig. 2, which has been in service since May 1944. Throughout the life of the galena operation, delivery of extremely muddy ore to the mill overloaded the medium cleaning system, and it frequently was necessary to cut off the feed and clean the medium for several hours until its normal viscosity had been re-established. The cleaning circuit

Jan 1, 1952

By J. O. Marsden, C. Green

In 2003, a high-temperature pressure leaching circuit to treat copper sulfide concentrates was commissioned at the copper/molybdenum operation at Bagdad, AZ. In late 2007, a medium-temperature pressure leaching circuit was commissioned at the Morenci mine in Arizona. The Morenci circuit was shut down in mid-2008, following a fire in the autoclave circuit. The onset of the global financial crisis in late 2008 resulted in significant changes to the operating profile in the Southwestern United States with respect to concentrates production, concentrates treatment, acid production and acid consumption. As a result of these changes, the Morenci concentrator was shut down, and the pressure leaching circuit remained offline. In late 2014, the increasing acid requirements in the Southwestern United States prompted a reevaluation of the Morenci concentrate leaching facilities. As a result, the pressure leaching circuit was restarted in high-temperature (200 °C) mode in May 2015 and has operated successfully for three years since recommissioning. This paper describes the current pressure leaching circuit configuration and the factors leading to the successful application of copper sulfide concentrate leaching at this location.

The Mining Foundation of the Southwest will hold its 14th annual American Mining Hall of Fame awards banquet Saturday, Dec. 7, 1996 at the Leows Ventana Canyon Resort in Tucson, AZ. Each year, preceding the Arizona Conference of SME, the Mining Foundation sponsors this banquet to honor outstanding contributions by people in the mining industry. A permanent display of honoree vitae is located at the Arizona Historical Society in Tucson. Each year, one living award recipient and up to two honorees from mining’s history are chosen by the hall of fame committee and the board of governors of the Mining Foundation. In 1989, the foundation also established a medal of merit to recognize outstanding individual technical and professional contributions to the mining industry. And, in 1995, an award was created to recognize contributions made by companies and individuals in partnership with the mining industry. This year’s inductee is Richard de J. Osborne, chairman, president and chief executive officer of Asarco. He will also be the featured speaker at the banquet.

Jan 1, 1996

By Gustavo Angeloci

Artisanal mining is a rudimentary activity that today attracts over 30 million people in virtually all developing countries around the world. As the price of gold has steadily increased over the past decade, 15 million people have become involved in extracting this metal in 55 countries. Individuals have switched to mining from primary industrial sectors such as agriculture to increase their income. These workers generally have little capital, low education levels, and no previous experience in mining. Together with a lack of technical support from governments, these factors lead to disorganized and informal mining activities that generate environmental and social chaos. The absence of technical knowledge and capital has caused a proliferation of Gold Ore Processing Centres (GOPCs) around the world established by local entrepreneurs, who provide a way for miners to process their ores using amalgamation for a fee that is relatively low to non-existent. Gold recovery by the independent miners rarely exceeds 30 % and gold-rich tailings are left at GOPC facilities as a form of payment. GOPCs recover around 90 % of the remaining gold using cyanidation, flotation, and amalgamation, without any compensation paid to the miners. In processing these mercury (Hg)-contaminated tailings, Hg cyanide complexes are produced that are dumped into aquatic environments, leading to rapid bioaccumulation of Hg by fish. In the town of Portovelo, Ecuador, the establishment of partnerships between GOPC entrepreneurs and artisanal miners has proven to be successful in forming legal small-mining companies to create more equity and reduce pollution. About 108 GOPCs operate in Portovelo-Zaruma, with 40 % of these still working illegally without proper regulation and permitting. Over 20 % of these GOPCs continue to use grinding, concentrating and amalgamating of the gold, with 58 % performing cyanidation of tailings and/or gravity concentrates, and 15 % combining flotation with cyanidation. About 94 % of the GOPCs concentrate the ore prior to applying amalgamation, which significantly reduces Hg emissions to the environment. Incorporating flotation has given the operators increased skills in mineral recovery, with the side benefit of producing a copper concentrate as added value. Despite these innovations, mineral recovery is still inefficient, and waste management is a major challenge in creating true sustainability in this sector (technical efficiency together with social and environmental responsibilities). Further organization, training and capacity-building are needed. The principles of Lean Manufacturing Methods ("Just in Time" production and "Automation") are suggested as possible techniques to assist small GOPCs to become sustainable. In this concept, a larger mining company can become associated with artisanal miners in a partnership to provide training and investment for exploitation of small deposits that would be infeasible as a single large operation. As well, an International Training Centre for Artisanal Miners (ITCAM) is being established in Portovelo with collaboration of the Government of Ecuador to further enhance and upgrade mining activities in this region. ITCAM will provide artisanal miners with technical, business and environmental training to become responsible small-scale miners. In building this new capacity, ITCAM intends to create an atmosphere of trust to attract private and corporate investors to become partners with artisanal miners.

Aug 1, 2013