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By H. K. Lin

Residual cyanide in cyanidation tailings can be detoxified by its oxidation to cyanate, as in the Inco and Degussa processes. However, cyanate, the product of detoxification and other oxidation processes, may be reduced to cyanide in reducing environments, e.g., deepwater discharge of cyanidation tailings. This study shows that the reduc-tion of cyanate to cyanide occurs and that the reduction rate increases with decreasing solution redox potential. Solutions with lower pH favor the reduction rate. No significant difference was observed between the results of tests prepared with distilled water and seawater, and the presence of cyanidation solid tailings does not show an effect on the reduction. Because cyanate can be reduced to toxic cyanide, causing environmental concerns, the deepwater discharges of cyanidation tailings must be handled carefully.

Jan 1, 2008

By Ian Farrell, Josh Stowe, Eric Wingeard

Tailings transport system design is generally based on identifying the minimum and maximum process boundary conditions for pump selection and pipeline sizing. The approach is robust and well-proven. However, the approach has the potential to skew selections to operating scenarios that have a very low likelihood of occurring, such as the combination of high solids throughput and low tailings solids concentration. The approach can result in a tailings transport system design that is overly conservative. A probabilistic method-based approach captures the independent variability of design inputs and the combined likelihood of outcomes. This approach identifies the process conditions that have the highest likelihood of occurrence and are most applicable to equipment and pipeline selections. An outline of a probabilistic-based approach to tailings transport system design and the resulting selections is provided in this article. The probabilistic-based system design is compared to the outcomes from the traditional approach. The benefits and challenges to this approach are discussed and recommendations for utilizing this approach for tailings transport system design are provided.

Mar 31, 2021

By Stephen M. Smading

The Jinping-II hydroelectric project in China features four parallel headrace tunnels approximately 18-km- (11-mile-) long. Two will be excavated by tunnel boring machines (TBM) and two by drill-and-blast. A nearby fifth tunnel is being excavated by a 7.2-m (23.6-ft) TBM to draw down ground water in advance of excavating the headrace tunnels. Unique onsite assembly of a 12.43-m (40.7-ft) main beam TBM and backup system was completed on Sept. 18, 2008 in the remote mountains of the Sichuan province. The equipment was assembled onsite, without previously having been assembled and tested in a factory, using a method called onsite first time assembly (OFTA). This paper addresses the following topics: ? Project description including geology and terrain. ? The decision process leading to onsite, first time assembly, the assembly process and logistics, and lessons learned. ? Design features of the TBM and backup system. ? Operational history from startup to the writing of this article.

Jan 1, 2009

By F. D. Fox

The Flambeau and Ridgeway Mines, both owned and operated by wholly owned subsidiaries of Kennecott Minerals Company, were located very close to populated areas having initial concerns about health, safety and the environment. The success of both operations depended upon developing a framework of community support and enhancing sustainable development opportunities throughout the entire life cycle of the mining operations to address these concerns. The protection of the Flambeau River was the cornerstone of the Flambeau Mine’s success. The highest priority for the Ridgeway Mine was to ensure long-term physical, chemical and ecological stability of the reclaimed mine site. Both of these goals have been achieved and are discussed in this paper, which highlights Kennecott Minerals Company’s integration of sustainable development principles into its business decision-making and management processes.

Jan 1, 2003

By X. Zhou

In this study, the cyclonic static microbubble flotation column (FCSMC) was investigated for fluorite beneficiation. The structure and principle of the specially designed column are described. Fluorite samples from the tungsten separation tailings of the Shizhuyuan Mine, Chenzhou, Hunan Province, P.R. China, were tested using a small-scale continuous flotation test unit, and concentrates with a fluorite grade higher than 98% were obtained. One rougher and three cleaner stages in the FCSMC achieved the same separation performance as one rougher and eight cleaners in conventional flotation cells. This greatly simplified the flotation circuit and reduced operating costs.

Jan 1, 2007

By Amanda Elioff

Success of the Gold Line Eastside Ex-tension rail tunnels in Los Angeles, CA has prompted the Los Angeles County Metropolitan Transportation Authority?s (Metro) planning new rail lines to include underground alternatives. The Westside Extension Transit Corridor alternatives include up to 27 km (17 miles) of subway to be constructed in soft ground. The routes will require construction in Los Angeles? ?potential methane zone,? which was not considered for subway construction until recently. Slurry face tunnel boring machines (TBM) will likely be specified.

Jan 1, 2009

By Kevin Andrews, Terry Hamric, Scott Nelson

"Mining conditions in underground coal mines are dictated by the environment in which the coal seams were geologically deposited. Depositional features can change rapidly, significantly affecting mining conditions. Mine geologists understand factors affecting mining conditions, predict future conditions, and provide guidance to mine management. A case study demonstrates how a mine in Appalachia merged an understanding of depositional environments with mining conditions and drilling data to make informed decisions as the mine encountered geologic anomalies. The assessment included drilling, mapping of geologic hazards and mine productivity, and creation of a conceptual depositional model. Metallurgical coal quality and clean tons per foot served as incentives for continued advance. Mining in the south was historically favorable, with good production and advance rates. As mining advanced north, changing geologic conditions caused the upper seam split to abruptly disappear. The mine ramped down into the lower seam split. Mining in the north area encountered unfavorable conditions, including transition roof, “horsebacks,” sandstone intrusions, roof rolls, and bony floor, resulting in low rates of mining advance. The mine geologist characterized the features and created a predictive model for future mining. Most of the adverse conditions were attributed to the coal in the north being part of an incised, transgressive valley fill environment, as compared to the favorable conditions in the south resulting from a floodplain depositional environment. Geologic conditions, low productivity, and unfavorable future predicted conditions in the north ultimately resulted in mine closure and reallocation of resources to a new mine with better forecasted conditions.INTRODUCTIONThe role of a geologist in assisting coal mining operations to understand and predict the impact of varying geological factors on mining productivity is a critical one, especially when management decisions must be made about the future prospects of a mine operating in difficult conditions. Chase, Newman, and Rusnak (2006) provide a very thorough discussion of the evolution of the role of the coal mine geologist and emphasizes the importance of understanding geology with regard to mine management decisions. Using actual mining performance data to determine which geologic factors are the most critical for mining is a powerful tool for making informed mine management decisions. For example, Nelson, Mullennex, and Miller (1988) provide a case study of analyzing the geologic factors impacting productivity of a Kentucky longwall mine to predict future mining conditions for the operation. In that case, the difficult geologic factors for longwall mining were prevalent across much of the remaining permit area and, in response, mine management converted the operation from a longwall operation to a continuous miner (CM) operation to better adapt to the geology. In another example, Keim and Miller (1999) evaluated geologic conditions impacting a West Virginia longwall mine. In both examples, significant geotechnical and geological information was available, including the opportunity to compare predicted mining conditions against actual conditions as mining progressed. Numerous examples of advanced Geologic Hazard Mapping (GHM) methodologies have come from government agencies and academia. For example, development of the Coal Mine Roof Rating (CMRR) system (Molinda and Mark, 1994) provided a standard means for geologists and engineers to communicate quantitatively with regard to mine roof conditions, and the introduction of the Stability Mapping System (SMS) provided an efficient means for analyzing numerous factors affecting coal mine stability (Wang and Heasley, 2005)."

Jan 1, 2019

By N. Loganathan, Tan Boon Tee, Joe O’Carroll, Richard Flanagan

In recent years, tunnelling activities in Singapore have increased considerably with the construction of extensions to the existing sub-surface transport system, a deep tunnel sewerage disposal system, and tunnels for the laying power cables and other utilities. These tunnels are excavated through urban areas, adjacent to high-rise buildings, depressed road structures, beneath other tunnels, and buried services. Earth pressure balance (EPB) tunnel boring machines (TBM) have been used extensively in Singapore with great success. The risk associated with soft ground tunnelling, including tunnelling through Old Alluvium, can be minimized with an understanding of the geology, geotechnical parameters, and the tunnelling-induced behaviour of Old Alluvium (OA The purpose of this paper is to present some design and construction aspects of EPB TBM tunnelling through Old Alluvium.

Jan 1, 2005

By R. B. Toombs

In describing the Canadian mineral industry in a world setting, this paper examines the industry from four points of view. First, mineral industry growth is related to trends in economic activity thereby providing a measure of the industry's importance in the Canadian economy. To give perspective to the Canadian scene, reference is made to economic trends in several of the world's leading mineral producing and mineral consuming countries. The Canadian mineral industry is next examined in terms of its major developments of the past 20 years and the resultant size, structure, and production diversity of 1964. The position of the Canadian mineral industry in the world industry is then analyzed by tracing changes in mineral supply and demand patterns. Growth of the Canadian industry depends greatly on expansion of export markets because three fifths of the value of production is accounted for by exports. Finally, attention is directed to the outlook for the Canadian mineral industry. Problems facing the industry are surveyed, and an appraisal is made of economic policies that have encouraged industry growth. A forecast of mineral production value in 1970 is included.

Jan 1, 1964

By Pierre Dosmond

In ore mining technology, the loading and hauling operations are undoubtedly the area where the most spectacular progress has been made during the last twenty years. I shall draw some examples from the Eastern France iron ore mines which I how well and whose production of 62 million tons for 1962 and 1963 constitute a worthwhile experience worldwide. The iron ore deposits of Lorraine are of sedimentary origin. They contain many mineralized horizons with workable seams situated from 330 to 830 ft. in depth. The dip of these seams is generally less than six percent. Their thickness varies from 6 to 23 ft. All seams are not workable throughout the whole area of occurrence, but in some mines there are five mineable seams in the same vertical section, with from 5 to 20 ft. of barren ground intervening between them. The iron content of the mineral varies from 28 to 36 percent. Specific gravity of the ore is 156 lb. per cu. ft. m place and 100 lb. per cu. ft. blasted. Reserves of iron ore in the Lorraine region are estimated at six billion tons with an iron content of more than 28 percent. These mines operate by means of rooms and pillars process, with pillar robbing; the final recovery is very good and averages 90 percent. Some years back, competition from richer, imported ores incited these mines to make constant efforts to increase their productivity and reduce mining costs, thus placing them in a leading position in mining technology, as evidenced by the dramatic evolution of their output per manshift (Figure No. 1).

Jan 1, 1970

By L. A. Weakly, D. A. Weiss, R. B. Crookston

A presentation of experience gained from using mechanical and conventional equipment for excavating shafts, raises, tunnels and other openings in various Colorado oil shale mining properties.

Jan 1, 1983

By S. Dixon

The Phelps Dodge - PD/PERI Heap2D Model is a phenomenological stockpile leaching model that has been used to investigate the best operating practices for leaching chalcocite. The model was used to investigate the interrelationships of raffinate application rate, aeration rate, raffinate iron grade, acid cures, lift height, crush size, bulk density, air injection spacing and raffinate drip emitter spacing.

Jan 1, 2006

By Dan Witkowsky

In an increasingly environmentally conscious world, mining's importance to society has often been misunderstood and even maligned by the public. Extreme and impractical ideas have often been presented to children because of the lack of accurate, timely resource materials available to educators. In the late 1960s. two mining engineers, S.P. "Pi" Warren and C.L. "Lindy" Barker, became aware of this situation. They proposed to develop a summer field course to provide a factual overview of the minerals industry for teachers. The pair believed that teachers could become better informed to educate students, and future generations, about mining. These two Colorado Mining Association (CMA) members felt that such a course could reduce much of the misunderstanding about this vital industry. This could be done by providing a balanced perspective of mining, not only for kindergarten-through-grade-12 teachers, but also for the students they would be teaching during their careers. Students who better understood the minerals industry could better formulate an unbiased view of it. The course would seek recognized authorities from industry, academia and government who would lecture in their respective fields of expertise. The course would provide a total concept of the coal, aggregate, metals and industrial minerals industries. It would include geology, geophysics, exploration, mining, processing, marketing, product applications, economic, mining history, careers, and environmental responsiblity. When possible, site visits would permit educators to view operations and to meet the men and women who are industry leaders. Teachers would pay a small tuition fee. The balance of the program expenses for each teacher would be paid through scholarships provided by industry and individuals. The "total concept" idea obtained the support of the minerals industry. The support of CMA's Education Committee and the Colorado School of Mines (CSM) was obtained in 1968. Colorado's Commission on Higher Education approved teacher recertification credits through CSM's Office of Special Progams and Continuing Education for those successfully completing the program. The first six-week series of classes presenting the total concept of the indus¬try was held at CSM in 1969. In 1977, the CMA Education Foundation Inc. (CMAEF) was established as a Colorado nonprofit corporation. The "Total Concept of the Mining Industry" (Total Concept) course was placed under its sponsorship. CMAEF is dedicated toward this continuing education program (Table 1). In 1994, the course was streamlined to four-weeks for six hours recertification credit.

Jan 1, 1997

Multilevel-multiseam hardcoal mines on the European continent usually consist of a huge network of underground openings, sometimes more than 200 km long in total, with some longwalls operating down to a depth of 1,500 m. While operating several longwalls simultaneously, these mines are making use of a number of stationary and mobile measurement- and analysis units in their main ventilation passes combined with atmospheric measurements on the surface. This paper provides an overview over the systems and technology used and describes the typical set-up of a measuring net. To detect and monitor underground fires through fire gases measurement and -analysis, a mobile underground testing laboratory collects data locally in the area of the fire. These laboratories have proven to be extremely useful not only during the actual fire fighting but also for the long-term gas measurements in critical mine areas. They have repeatedly detected starting fires and have thus given the mine the opportunity to react early and to avoid larger damage. Therefore several mobile laboratory units have now been installed for long-term testing in a number of German mines and similar units are being used in the Czech Republic and Poland.

Jan 1, 2012

By C. Keefe, O&apos

Measurements of the quantity of entrained air within processes have challenged instrumentation developers for years. This is particularly true in the unique and demanding operating environment and applications seen in minerals processing. In minerals processing applications, entrained air plays a role in errors seen within nuclear density gauge measurements and in pumping efficiency. It is also the major component of flotation processes. The measurement of the quantity of entrained air, known as the gas void fraction, can now be performed from the outside of a process pipe through CiDRA?s patented passive sonar array-based technology. Within column cells, the need for a robust, no maintenance, accurate means of measuring the entrained air, known as gas holdup, has resulted in a submersible version of this technology. CiDRA?s meter technology calculates the gas void fraction by first measuring the speed at which naturally occurring sound in the process slurry propagates past an axial array of sensors. These sensors are incorporated in a band that is wrapped around the outside of the pipe, resulting in no process downtimes for installation and unprecedented reliability. A known relationship between this speed of sound and the entrained air captured in the form of bubbles within the slurry is then applied in CiDRA?s meter to calculate the gas void fraction. This paper will present the measurement technology, its operation, its calibration and its application in a variety of gas void fraction and gas holdup measurement situations such as pumping efficiencies, hydrocyclone operation, external sparging, and column cells.

Jan 1, 2008

By Raymond W. Henn

The 30th annual short course ?Grouting Fundamentals and Current Practice? was held at the Colorado School of Mines, June 22-26, 2009. The field demonstration portion of the course was conducted June 25, at Hayward Baker, Inc.?s yard in Broomfield, CO. The full-scale field demonstration annually presents many different types of drilling equipment being operated as well as various grouting methods being performed under different field conditions. As part of the field demonstration, the class is shown the proportioning, mixing, testing and injection of various cement grout mixes into sand columns under controlled and measured conditions. These sand column demonstrations have been conducted under controlled and measured conditions each year since 1999 as part of the short course. The sand column demonstrations were conducted prior to 1999, but with less quality control and minimal record keeping of the proportioning, mixing, testing, injection pressures and the final permeation results. The goal of the sand column demonstration is to show the students the effect of the water cement ratio and the use of admixture as well as the fineness of the cement, portland versus ultrafine, used has on the engineering properties of the grout and the grout?s vertical permeation through the sand. Test results for the demonstrations conducted in 1999 and for two separate demonstrations, one at the grout course and one at Geo Denver, conducted in 2000 were published in the 2001 proceedings of the Rapid Excavation and Tunneling Conference (RETC) (Henn et al. 2001). The test results for the 2002 and the 2003 demonstrations were published in the 2005 proceeding of the RETC (Henn et al. 2005).

Jan 1, 2009

By P. J. Miranda, C. G. Anderson, L. G. Twidwell

Titanium is a metal of increasing worldwide strategic importance. The Center for Advanced Mineral and Metallurgical Processing (CAMP) at Montana Tech of the University of Montana is currently directing two titanium research initiatives. The first program, Titanium Extraction Mining and Process Engineering Initiative (TEMPER), is focused on producing low cost titanium through the identification and development of new mining, beneficiation and extraction technologies which will significantly reduce the cost of titanium production. This will directly benefit worldwide commercial applications. Secondly, CAMP is evaluating new technologies for fabrication of titanium utilizing the Free Form Titanium Fabrication (FFTF) initiative. These technologies may drastically reduce the cost and time to manufacture titanium components. Because of the high strength to weight ratio of titanium coupled with its superior corrosion characteristics, these programs will be of vital importance to expanding the commercial and strategic applications of titanium. An overview of these two new titanium initiatives will be presented in this paper.

Jan 1, 2005

By K. Oraee

Mining of copper ore and the related industries play an important role in Iran?s economy. Copper ore production in Iran accounts for 75% of the total production in the Middle East. All activities related to copper, that is, exploration, production, refinement etc are owned and managed by state owned companies. Decisions have been made to privatize all these activities. To assess the success of this privatization process, different components of the industry must be subject to economic analysis. In this paper, the cost estimation of all operations has been carried out. The total potential and attainable revenues have also been estimated using historical data available from the industry. Risk is a major factor in all mining activities and the copper industry of Iran has been subject to risk factors arising from many internal and external variables. These variables have been recognized and their effects evaluated. The effect of risk on the economic feasibility of the operations in the industry has also been analyzed.

Jan 1, 2011

By Yousef Ghorbani, Abolfazl Danesh, Fatemeh Kazemi, Ataallah Bahrami, Morteza Abdollahi, Mohammad Raouf Hosseini

This study aims to investigate the effects of operational variables on concentrate grade, recovery, separation efficiency, and kinetic parameters of the copper flotation process. For this purpose, the effects of the pulp solids content, collector and frother dosage, and preparation and concentrate collection time were studied using a Taguchi experimental design. The results of statistical analyses indicated that the concentrate collection time and pulp density were the most influential parameters on concentrate grade. Considering copper recovery, concentrate collection time, collector dosage, and pulp density were the most significant variables, in decreasing order of importance. Also, the separation efficiency was mostly influenced by the concentrate collection time. Furthermore, kinetic studies showed that the second-order rectangular distribution model perfectly matched the experimental flotation data. The highest kinetic constant of 0.0756 s−1 was obtained from the test, which was performed with 35% solids content and 40 and 20 g/t collector and frother, respectively. The highest predicted copper recovery of 99.57% was obtained from the test at 30% solids content, and the collector and frother dosages of 40 and 15 g/t, respectively

By S. S. Peng

In dealing with the mining engineering problems, the traditional approaches of laboratory experimental simulations and/or analytical solutions are not very effective. Mainly because the field problems are too complex to be solved with a few simplified assumptions. Conversely it is also true that the experimental and analytical/ numerical models currently available are far from being able to model the actual cases. Under such conditions, the most effective mean of research into mining engineering problems is to combine the mine (field) investigations with laboratory and / or analytical modelings. It is with this concept in mind this research was initiated in 1973. 'The field investigations which began in the fall of 1978 consisted of mainly visiting the mines where surface subsidence monitorings had been or were being monitored and/or surface structural changes had occurred. From such visits, subsidence data were collected. A quick analysis of those data provided preliminary understandings of the characteristics of the surface subsidence parameters in the regions (1-5). Using those date, models of various types are being developed for subsidence prediction / control. So far, a total of 44 longwall subsidence profiles in 22 longwall panels and 10 room-and-pillar profiles in 5 room and-pillar sections have been collected. This paper summarizes the combined results published previously (1-5) and present the preliminary results of the predictive models developed.

Jan 1, 1982