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By F. F. Sharpless

ON Saturday evening, Sept. 9, a small party of Institute members, their wives and friends, left New York to attend the Fall Meeting of the Institute at San Francisco. In this party there were: President and Mrs. Arthur S. Dwight; Mr. and Mrs. George D. Barron; Mr. and Mrs. H. J. Stehli; N. S. Spencer and Miss Spencer; the Secretary and Mrs. F. F. Sharpless. They were joined at Chicago by E. F. Eurich, and by Mr. and Mrs. R. L. Baldwin and daughter. Our party was met at Chicago by Mr. and Mrs. L. V. Rice, Mr. and Mrs. A. D. Terrell and W. F. Boericke, who constituted themselves an impromptu entertainment committee and proceeded to carry out a delightful little program. We were taken to the Lake Shore drive, where a stiff wind off the lake refreshed us after a sultry day on the train, and on our return to the city saw Chicago illuminated with all its brilliance of electricity. We were entertained at dinner at the Drake Hotel. In spite of being two hours late getting into Omaha, we were right on the dot at Denver on Tuesday morn-ing. Horace F. Lunt came to the hotel soon after breakfast, and told us that a trip to the mountains had been planned. Having learned the number in the party, he began to gather up his automobiles for a 10 o'clock start.

Jan 10, 1922

By P. Condori

Palabora Mining Copper (PMC) has two autogenous mills that have been in operation since 1976. The mills were originally designed to treat 30 000 t/d of open cast copper ore in a closed circuit with cyclones. As the ore body went deeper the open cast method of mining was changed to block caving, a consequence of this was the dolerite content (hardest barren material) increased significantly, increasing the production rate of pebbles and thus reducing the milling capacity. In order to cope with the increased ore hardness and to increase mill capacity, a second ball milling stage and pebble crushing were incorporated to the circuit. The above actions created new challenges to the circuit operation and bottlenecks in different areas of the milling circuit. This paper reports the holistic work performed on the Palabora autogenous milling circuit including the implementation of a mill constraint control scheme, the implementation of a pebble removal system from the circuit and a new circuit configuration. The achieved plant stability and increment of ore throughput are also reported in this paper.

Jan 1, 2012

By Eddy Dénommé, Deni Villeneuve

"Niobec mine, a producer of pyrochlore concentrates since 1976, became a producer of ferroniobium in 1994 and achieved accreditation to the ISO 9002 standard in 1995. The goal of ISO 9002 is to ensure that the products supplied to clients regularly meet their specifications, through explicit work standards and procedures throughout the production process, from deposit appraisal to ferroniobium production.A key element of ISO 9002 implementation at Niobec consists of the quality control procedures applied to the raw materials: the ore fed to the mill and the pyrochlore concentrate fed to the reduction plant. These controls extend from exploration, deposit appraisal, mine planning and reserves estimation, mining, mineral processing and, finally, ferroniobium production. The implementation of ISO 9002 has allowed more efficient control of the quality of the final product sold to clients. It requires interactive team work, the role of the geologist being to relate all information pertaining to raw material and product quality to the geological framework of the deposits."

Jan 1, 1997

There is a significant amount of historical mining and exploration information available. This information is often distributed throughout a number of reports or plans, available from a variety of sources, and in many differing formats. The ability to capture paper-based historical information in a modem digital format provides mining and exploration companies with valuable information that can be used in a number of ways; for example, reassessments of exploration or mining work previously undertaken, or used in conjunction with current exploration information.   The purpose of this paper is threefold. Firstly, to present the paper-based historical information; highlighting some of the problems encountered, solutions to those problems, and any assumptions used. Secondly, to present the historical data in digital format, and demonstrate the tools available to analyse geological and associated information, and finally, to illustrate some of the potential future applications of the information, including mining optimisation, mine design and scheduling.   The Glenorchy scheelite/gold prospect has been used as an example. Within the overall prospect two smaller areas were selected. The Mount McIntosh and surrounding areas, focuses on exploration and surface excavation information. The Mount Judah area (State and Kelly-Taylor workings) focuses on underground mining and exploration information.  

Jan 1, 2001

By Peter Hayes, Evgueni Jak, Ata Fallah Mehrjardi

Modern analytical tools, such as electron probe X-ray microanalysis (EPMA), are used in experimental characterization of phase equilibria and microstructures of complex slags. Integrated thermodynamic computer packages, such as FactSage, are used to provide more accurate descriptions of complex slag systems. These advanced methodologies have been applied to characterize dynamic steady state freeze linings in slag systems using submerged cold finger probes at controlled laboratory conditions, establishing the effects of bath chemistry, temperature, heat extraction rate and bulk fluid flow. It has been found that stationary freeze lining deposit interface temperatures at steady state conditions can be lower than the bulk slag liquidus temperature, and that stable operation below the liquidus is possible. A conceptual framework has been developed to explain the phenomenon and the range of interface temperatures that can be obtained in dynamic steady state conditions. These findings have important implications for the design of freeze linings and possible improvements to high-temperature metallurgical operations.

Jan 1, 2014

By Moussa Wone, Jeff Peterson, Filippo Azzarà, Daniele Nebbia

The DC Water and Sewer Authority's Long Term Control Plan includes tunnels, sewer separation, pumping station rehabilitation and green infrastructure to reduce combined sewer overflow (CSO) discharges to the District waterways. The Northeast Boundary Tunnel is a deep, large sewer tunnel that will reduce CSO discharges; signifi- cantly mitigate known chronic flooding in the Northeast Boundary drainage area and improve the water quality of the Anacostia River. This paper presents the unique combination of Owner and Contractor perspectives of the entire Project from conception through procurement, execution, and contract management, providing lesson learned, chal- lenges encountered, and solutions implemented to deliver the Project successfully.

Jun 23, 2024

By Yuting Xue, Xin Li, Ihsan Berk Tulu, Gaobo Zhao, Deniz Tuncay, Mindi Ruan

Most coal mine roofs in the Appalachian region consist of laminated shale, which is prone to brittle failure. Accurate modeling of shale roofs is vital for studying cutter failures of these shale roofs, and ordinary and formational bedding planes play a significant role in the response off the shale roof to mining-induced stresses. This paper presents a robust method for constructing three-dimensional shale roof models using limited borehole cores and leveraging image processing techniques. The approach begins with image extraction from shale cores. Then, we extract the portions that feature the core and employ image-stitching techniques to merge them seamlessly. Once the images are stitched, they are duplicated horizontally and merged to create a cross-sectional plane image representing a shale roof. This roof cross-sectional plane image serves as an input to our proprietary Digital Image Processing (DIP) algorithm, which is adept at extracting ordinary bedding planes (interfaces that represent color transitions between a single shale unit). The extraction process involves transforming discrete core points (ordinary bedding plane pixels) into continuous lines representing ordinary bedding planes. Finally, extending this method into the third dimension, the model is further extrapolated to form a comprehensive three-dimensional shale roof. Through this process, the geometry information of ordinary bedding planes can be extracted for each type of shale in cores, including sandy shale, gray shale, dark shale, etc. This work bridges the gap between limited core data and comprehensive 3D geological modeling, offering valuable insights into identifying and quantifying the variations in different shale roof geologies.

Jun 25, 2024

Gold mining in Australia and globally has a long and variable history. In recent years, due to ongoing public concern over long-term environmental impacts, the mining industry globally has been moving towards a more sustainable framework, presented as the æMining, Minerals and Sustainable DevelopmentÆ (MMSD) framework at the Johannesburg Earth Summit in 2002. There are a number of fundamental issues and concerns with assessing the sustainability of mining. Firstly, long-term trends show that ore grades for almost all metals and minerals will continue to decline (some rapidly so), increasing waste rock is being produced due to the trend towards large-scale open cut mining and more complex ores are now commonly being developed. The impact of these trends on the resource intensity, or unit cost, of gold production is of major concern as it could lead to an increase in energy, water and reagent consumption and greenhouse emissions per unit gold produced. A detailed compilation of these fundamental sustainability indices for gold mining has been undertaken, and is presented with respect to indices over time, ore grade and ore throughput. A clear observation is that the resource intensity of gold mining is extremely sensitive to the ore grade, with energy, water and cyanide consumption and greenhouse emissions rising significantly as ore grade decreases. Based on the gold ore resources at operating mines and other known gold deposits, it is most likely that the average gold ore grade will continue to decline, leading to increased resource intensity and consequent environmental impacts (assuming no breakthrough new technologies occur). These findings are of major importance to understanding the sustainability of gold mining. The final judgement of the sustainability of gold mining therefore must take into account the sensitivity of the ore grade in the resource intensity of gold production.

Jan 1, 2007

By Ari Kokko

Metso has a long history supplying boilers for high ash coal firing. These boilers are based on circulating fluidized bed (CFB) technology. CFB?s biggest benefit is fuel flexibility ? it can burn fuels from high moisture content to high ash content. Metso has delivered tens of CFB boilers burning waste or high ash coal starting on 80?s. Some of the boilers have been in operation twenty years meaning that there is a long term experience from these plants available. This feedback includes boiler performance and maintenance issues of the boiler. Metso is also delivering coal washing plants to improve coal quality, i.e. reducing ash content of the coal. The idea to combine coal washing plant and CFB boiler was made up two years ago in Metso. Up-coming legislation of coal washing and restrictions for washery reject land-filling in India are good drivers for this kind of concept. Pre-study of this kind of concept led to the conclusion that coal washing process can be fine-tuned so that reject?s calorific value is only 1100 kcal/kg and that was set as a target for boiler design. Metso shipped 200 tons of washery reject to its own research center located in Tampere Finland. First a wide range of fuel characterization tests were done in lab-scale and after that one week test run in 4 MW CFB pilot boiler was done. Test run proved that 1100 kcal/kg can be fired without any support fuel with special boiler design. Test run results gave a good set of data regarding combustion efficiency, emission performance and boiler dynamic behaviour when burning this kind of fuel. These results are introduced in this paper. This paper introduces also the CFB boiler concept for washery reject firing including boiler plant, fuel and ash handling systems and flue gas cleaning system. Power plant can be integrated with coal washing plant so that boiler size matches with washing plants c

Sep 1, 2012

By Christoph Aichinger

The optimization and improvement of a modern integral iron and steel works gets more and more difficult as each individual plant is already operated at its best efficiency and at the lowest operational expenditures. However very often the individual plants are considered as stand-alone units and there are losses and inconsistencies on interfaces and take over points, which could be avoided and by that improving the overall performance of the iron and steel works as a holistic unit. Primetals Technologies looked into this subject extensively in the recent years and is now ready to offer new tools and services in order to assist operators to find further potential for improvement in processes, which seem to be fully developed at first sight.

Aug 17, 2017

Since the beginning of the computing age, technical software packages have not been developed to address only programming specialists but have been dedicated to process engineers. For process analysis, BRGM is developing and commercializing three packages: ? sampling software: ECHANT 2.0 for Windows ? material balance calculation: BILCO 2.0 for Windows ? steady-state simulator for plant design, adaptation and optimization: USIM PAC 2.1 for Windows This paper deals in a first part with the main features of these three packages. In a second part, advanced models are presented for SAG/ AG mills and flotation columns. An industrial case of application is shown for each of them.

Jan 1, 1997

By John R. Marks

Introduction An engineer is a builder and a problem solver. He uses knowledge of the properties of matter and energy to furnish the needs of society. Engineers form the bridge between scientific researchers and the general public, most of whom are technologically illiterate. Mining, metallurgical, and petroleum engineers extract minerals from the ground and process them into usable forms. Then, other engineers further process them into society's needs. Minerals engineers deal with more uncertainty than other engineers. Each ore deposit has its own personality and each ore is metallurgically unique. Minerals engineers, therefore, must be flexible, often applying larger safety factors and contingencies than other engineers, and frequently functioning as a jack of all trades. A minerals engineer can work in coal, oil, oil shale, base metals, ferrous metals, precious metals, industrial minerals, strategic minerals, or in exploration. Other mining jobs include banking and financing, education and research, marketing and sales, and government. As a minerals engineer, you may be among the first to work on the ocean floor or the moon. College Preparation A difference between college and industry is the type of problems to be solved. A typical college problem has an exact answer derived from given information. An industry problem is more apt to have a solution chosen from a number of alternatives. Information required for the solution is not given. It must be measured, calculated, looked-up, estimated, or otherwise derived. Solutions involve trade-offs, economics, and human factors, as well as application of physical laws and theory. When a college problem is answered, you move on to the next one. In industry, however, the headaches may just be starting with the implementation of the solution. Students often complain that they see little use for the theory they are learning. This is valid. A good professor will link theory and practice. Another difference between college and industry is the price of failure. In college, you can make a half-hearted effort in an assignment and take your C or D. On the job, however, poor engineering results in potentially effective projects being rejected and unsound projects being undertaken. Poor performance results in cost overruns, schedule holdups, oversights, disgruntled employees, irate bosses, unsafe structures, and unreliable systems. The costs are time, money, and possibly lives. The student pays the university for his work - not the other way around. So the rewards for good schoolwork often seem nebulous. But education must be viewed as an investment. Working for good grades will help you think better, learn more, receive better job offers, and perform more effectively on the job. There is no substitute for hard work. Avoid taking the easiest electives. If you desire a more liberal education or dislike rigorous physical sciences, mathematics, or engineering courses, change majors. Remember, you are training to be an engineer, not a computer programmer or market analyst. At least one summer of industry employment is necessary for minerals engineering students. The sooner you gain actual experience, the sooner you will know whether to change majors. Most large companies hire students during summer. It is best to send out applications around Christmas break. First and second year students usually work as laborers. Upper-classmen may work as engineering technicians. Students must sometimes choose between returning to a company at a higher position or trying a different company at a lower position, for more varied experience. Both alternatives have advantages. Do your best on these summer jobs. The company is watching. If you do well, the chances are good you will get a job offer when you graduate. Good references are important when you begin job hunting. Interviewing occurs near the end of your school career. The standard procedure is to send your resume with a cover letter to each company you are interested in. The resume for a graduating engineer with little experience need not exceed one page. The cover letter must be written for the individual company.

Jan 2, 1985

By Thomas H. Dubaniewicz

The National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, conducted a study of past mine explosions to identify the ignition locations and ignition sources responsible for the most severe explosion events resulting in death. Since the Scotia disaster of 1976, many fatalities from underground coal mine explosions have been linked to nonpermissible electrical equipment ignition sources located in intake air courses. With few exceptions, explosion protected equipment is generally not required in intake air courses of gassy underground coal mines in the US. Cigarette lighters were another prevalent ignition source for fatal explosions ignited in intake air courses. Several mine rescue/ recovery teams have encountered electrical ignition hazards. The study provides evidence that intake air courses of gassy underground coal mines fit the description of certain Hazardous (classified) locations described in the US National Electrical Code®. Class I Division 2 or Zone 2 explosion protection tech¬niques may be used to design intake air equipment so that it does not present an ignition source under normal operation, before mine power is shut down in emergency situations. Nonpermissible circuits in intake air courses that are likely to remain energized during emergencies, e.g. battery powered equipment, should be protected by more stringent Class I Division 1, Zone 1, or Zone 0 techniques, to protect rescue/recovery personnel.

Jan 1, 2009

By Xing Jin, Dan Graffi, Glenn MacPherson, Dan Rioux

"The complexity of a modern flotation circuit makes it susceptible to disturbances such as changes in feed, ore mineralogy, equipment degradation, poor measurements and faulty instruments. Good measurements and a robust control system are critical to create and maintain a stable and optimum flotation process.This paper focuses on the development and implementation of process control applications in the flotation circuits at Xstrata Nickel’s Strathcona Mill ( referred to as the mill hereafter ) in Sudbury, Ontario. Following the path of ‘stabilize-improve-optimize’, basic controls to stabilize process variables such as flotation cell pulp level, air and reagent addition rates, cleaning-column feed and wash-water rates have been established. Factors such as best practice in pulp level and valve position measurement, feedforward control and the application of an appropriate control philosophy, have contributed to the significant reduction in process variability. For instance, standard deviation reduction of 79% for the Ni impurity in the column Cu concentrate grade was experienced and is shown. The variability reduction of the flotation circuits’ key process-variables paves the way to further improve and optimize flotation performance. A grams-per-metal unit reagent addition control scheme has been improved upon, particularly for different operating scenarios and better robustness. In addition, following significant stabilization of the primary controls and columns feedrates, Cu/Ni separation cleaning-column bias-control (cascaded to the wash-water rate) and hold-up control (cascaded to air flowrate) have been developed and tested. This strategy – from stabilization to optimization - is expected to achieve a more consistent control of final concentrate grades and improve recoveries.INTRODUCTIONFlotation is considered the most important and value-added process in the milling metallurgical plant and is still undergoing continuous evolution to treat greater tonnage and different ores (Wills, 2006). Starting over three decades ago, with the advent of on-line slurry content analysis devices, flotation automatic control has received persistent interest and a large number of applications have been reported (Thwaites, 1983, 1986 ; Mckee, 1991). Bergh and Yianatos (2011) reviewed different aspects of process control in flotation circuits and have evaluated the applicability of model predictive control to the process. Mckee (1991) analyzed the difficulty in developing lasting/robust process control applications for flotation circuits and stated that the path of stabilization-refinement-optimization would more likely lead to successful flotation circuit process control. Best practice on column process control was discussed by Bouchard, etc. where a multi-layered approach was proposed, provided that the measurement of column process variables ( i.e. bias, froth depth, hold-up, etc. ) are measured reliably (Bouchard & Thwaites, 2008). Wills (2006) stated that the best practice for flotation automatic control starts with fulfilling basic control objectives, such as stabilized flotation cell level, air flow, pH, reagent flow etc., before considering more advanced, or even optimal, control of metallurgical targets, which are more closely linked to economic performance."

Jan 1, 2013

By A M. Myrvang, B Nøst, N Q. Trinh, I S. B Bergh

The iron ore producer Rana Gruber AS is situated in northern Norway just below the Arctic Circle, and has been producing hematite and magnetite concentrates for more than 60 years. Since the late 1990s, the major part of the production comes from a sublevel stoping underground operation after many years of open pit mining. Despite moderate mining depth, the operations have experienced considerable rock stress problems due to quite high tectonic, horizontal stresses. To manage the problems, comprehensive rock mechanics investigations have been carried out by SINTEF, a major contract research organisation. This has included in situ rock stress measurements, laboratory investigations and numerical modelling. Based on this and practical experience, satisfactory design of vertical and horizontal pillars was achieved. At depth, the ore width increases from 30–40?m to more than 100?m. This, together with a major planned increase in production, called for a change of the mining method. After thorough investigations and considerations, it was decided to change to sublevel caving, very much like the LKAB system. The development of the new system has been closely followed up by rock mechanics measures, including 3D numerical modelling and comprehensive monitoring of deformations and rock stress changes. To achieve a satisfactory caving of the hanging wall, all vertical and horizontal pillars in the sublevel stoping area had to be removed. This has been a challenging task, and the development of the caving has been slow until recently. However, now the caving develops satisfactorily.CITATION:Bergh, I S B, Trinh, N Q, Myrvang, A M and Nøst, B, 2014. From sublevel stoping to sublevel caving at Rana Gruber, Norway – rock mechanical aspects, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 323–330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By Hong Yong Sohn

A novel flash ironmaking technology is under development at the University of Utah under the support of U.S. Department of Energy (DOE) and American Iron and Steel Institute (AISI). The history of the development from the conception of the idea to the current status will be discussed. The flash ironmaking process produces iron directly from fine iron ore concentrates without requiring cokemaking and pelletization/sintering, which will enable the technology to significantly reduce energy consumption and carbon dioxide emissions compared with blast furnace ironmaking. Unlike other gas-based ironmaking processes, this technology will not suffer from the problems of solid sticking and fusion. Current work is focused on the method of supplying the energy required to maintain the necessary temperature, as an intermediate step to determine the scalability for larger, industrial-scale pilot trials.

Jan 1, 2014

By J. Driscoll

After 30 years of success, Newmont Gold Company has temporarily ceased production from the original Carlin Pit. In late 1993, the Carlin East Decline was driven and an extensive underground exploration program was started. Today, Newmont Gold produces refractory ore from the Carlin East underground at the rate of 700 t/d (770 stpd) for an annual production of over 100,000 ounces. Over 70 underground miners enjoy the estimated 6-year mine life at Carlin East. About 70% of the ore at Carlin East is mined by mechanized longhole stoping with delayed cemented backfill. The remaining ore is mined by underhand drift and cemented fill methods.

Jan 1, 1997

By Joseph M. Driscoll

After 30 years of successfully mining gold, Newmont Gold has temporarily ceased production from the original Carlin Pit. In late 1993, the Carlin East decline was driven and an extensive underground exploration program was started. Today, Newmont Gold produces refractory ore from the Carlin East Underground at the rate of 864 t/d (950 stpd). Annual production is more than 3.1 t (100,000 02). More than 70 underground miners will be employed during Carlin East's estimated six-year mine life. About 70% of the ore at Carlin East is mined by mechanized longhole stoping with delayed, cemented backfill. The remaining ore is mined by underhand drift and cemented fill methods.

Jan 1, 1997

By Robert Gannicott

??A mining company without the burden of operating a mine ??Management focused on marketing a high-quality, run-of-mine range of Canadian diamonds ??Robust revenue stream ??Specialist diamond knowledge ??Canadian exploration and development expertise ??BUT ??Single asset revenue base from depleting ore reserve ??Limited influence on production plans

Apr 1, 2005

By H. Lowers, P. Hageman, S. Diehl, D. Fey

Understanding relationships between mineralogy, texture, microstructural features, and element distribution and residence in minerals, is critical for accurate modeling of mineral weathering in waste-rock piles. The morphology of minerals and deformation structures, such as veins and faults, are important factors that control: (1) fluid access to the mineral surface to initiate dissolution, (2) the distribution of trace elements, and (3) formation of secondary minerals. We characterized the mineralogy, textures, and chemical properties of waste-rock material at three sites at scales ranging from outcrop to micrometer scale. A comprehensive hand-sample to thin-section scale methodology utilizing light microscopy, scanning electron microscopy, electron microprobe, and laser ablation ICP-MS was used to thoroughly characterize the waste-rock material.

Jan 1, 2007