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By J. P. Jarrell

Environmental considerations are of increasing importance in determining the acceptability, schedule and cost of expansion ofCanada's uranium processing industry. Environmental considerations must be addressed in the early stages of facility planning. This results in a dilemma, as the process data needed to predict physical environmental impacts are not yet available from process design activities. Hence, a business risk is incurred if plant design is carried forward to meet these requirements prior to project (or site) approval. On the other hand, project scheduling normally mitigates against leaving process design engineering until such time as project approval is obtained. This paper examines the experience gained in Eldorado Nuclear's proposed expansion of refining capacity as viewed by an environmental engineering consultant. The history of the project and the relationship to process design functions in the two-year period prior to the Port Granby environmental hearings are reviewed. During the Port Granby public hearing, there was a consensus that normal operation of the proposed refinery could be successfully integrated with the site's natural environmental constraints. Moreover, the radiological impact from plant operations was demonstrated to be inconsequential. However, concerns were raised relating to plant upset and accident situations. These concerns are summarized. Process data requirements identified during the environmental hearings are discussed. Finally, the concerns for on-site burial of radioactive waste are reviewed. These concerns focussed on long-term stability of the waste in the presence ofgroundwater transport, erosion and glaciers. The AECB's position on waste management with regard to this project is reviewed in light ofthe implications for design.

Jan 1, 1979

By Robert H. Peters

The U.S. Bureau of Mines has prepared this report on strategies for maintaining high job attendance among underground coal miners because high absenteeism is a threat to miners safety and seriously hampers productivity. A substantial number of research studies on the effectiveness of various strategies for reducing absenteeism among the employees of nonmining industries have been reported in the literature. These strategies have aimed at improving job attendance through one or more of the following: (1) improving employment procedures, (2) overcoming problems that adversely affect one's ability to attend work, and (3) increasing miners motivation to attend work. Many of these strategies appear applicable to the mining industry, and are reviewed in the first half of this report. The second half of this report describes how one could develop and implement a program for maintaining high attendance at underground coal mines. The steps include: measuring and evaluating attendance levels; formulating attendance goals and an absenteeism policy; developing and implementing an attendance promotion program; and periodically going through the preceding steps known as recycling.

Jan 1, 1989

By J. Faitli, I. Tarján

One of the basic processes of process engineering is the production of dense suspensions. The major two equipment of this task are the periodically operating propeller mixer, and the continuously operating mixer tank based on the flow principle. In the laboratory of the Department of Process Engineering at the University of Miskolc, laboratory scale experimental setups had been built of both types of mixers in the frame of the FKFP 0504/1999 signed research project, supported by the Hungarian Ministry of Education. By these experimental setups many systematical experimental series had been carried out by test materials of water as the dispersing media and sand, power plant fly ash and magnetite as the granular solids. On the basis of the literature and these experimental investigations, scale-up methods had been developed for both types of mixers for the determination of the main technical parameters of industrial size equipment.

Jan 1, 2003

By B. K. Gorain

"Mining of low grade deposits along with the necessity to design and operate flotation plants with high throughput presents unique metallurgical and environmental challenges that need to be addressed to reduce project risks, improve project economics and to sustain the profitability of operations over the life of a mine.Some of the key challenges include poor recovery of valuables and concentrate quality issues due to complex mineralogy, the need to use poor quality water such as brackish or sea water, reduce environmental impact from the process, integrate flotation with hydrometallurgy to maximize precious metals recovery, escalation of capital and operating costs, use of unproven technology and constant use of larger equipment, high ore variability, worldwide constraints on resource availability and an ever increasing need for reliable metallurgical input to financial models to evaluate economic viability of projects.The need to develop effective solutions to these problems in a short time frame is becoming a key to the success of any new project and for sustaining the profitability of a mining operation. An integrated multi-disciplinary approach to problem solving is crucial with the need for a more lateral thinking along with strategic partnerships and collaboration involving the right players. This paper presents some of the key findings based on experiences from a large number of challenging projects and operations focused on solving complex flotation problems.INTRODUCTIONThere are various challenges to successful development of mineral resources. Most of the ore bodies being developed worldwide are of lower grades requiring high throughput to be economical. Many of these lower grade ore bodies have significant occurrences of deleterious and penalty elements that could render a deposit unworthy of development unless there are technological solutions to process them economically in a sustainable manner with minimal environment impact. Even in a high metal price scenario, the economics for some of these low grade ore deposits is marginal. From a metallurgical perspective, these ore bodies have complex mineralogy and use of any off-the-shelf technology is not always effective. Development of innovative processes are often required, which is expensive, time consuming and sometimes risky.This paper will provide a broader perspective on the steps involved in solving flotation problems for operating plants and for greenfield development projects. In addition, some of the key challenges in flotation of complex low grade ore bodies along with the economic benefits in developing solutions to these problems will be presented."

Jan 1, 2013

By V A. Tsukerman

Prospects a new energy saving method for an efficient destruction of the sturdy and hard materials (rocks, ores, frozen soils, concrete blocks, etc) û the Electric Pulse Discharge (EPD) method of materials destruction for green processing in mining and processing of mineral raw materials are considered.The EPD-technologies give additional possibilities for solving ecological problems at the expense of increase of integrated approach of utilisation of minerals and industrial wastes. The scientific and technical level of executed development of EPD method is sufficient for organisation of design work to develop substantially new equipment. A number of plants have been developed and tested, including plants for processing raw material with minerals of jewels, plants for selection of mica from rocks, and plants for processing the merging of artificial mica.

Jan 1, 2002

By Ernest Baafi

A simulation model RoadSIM using the ARENA modelling system has been developed to evaluate roadway development options for a given development panel configuration. The RoadSIM simulation system has provisions for variability/randomness in operations including cutting and loading at the face, tramming and discharge of coal to the boot end and availability of equipment. The modelling system provides a means for assessing the operational limitations of roadway development practices at a particular coalmine. It is a ?what if? tool that allows a range of equipment, configurations and operating practices to be assessed in terms of achievable advance rates and equipment utilisation. Output from the system is in the form of a dynamic visualisation as well as summary reports and detailed logs of operations over time.

Oct 1, 2009

By Stephen Iverson

The National Institute for Occupational Safety and Health (NIOSH) is currently performing research to help mine operators minimize the amount of loose or damaged rock surrounding a blasted opening. Improperly designed blast rounds can result in excessive wall rock damage that may reduce the rock mass competency and increase ground support requirements. Unnecessary blast damage can cause many safety and operational concerns including an increased potential for injury from rock falls and other hazards resulting from sub-optimal blast designs. This paper focuses on the ground control and safety implications of blast damage in underground mines. A reduction in rock quality due to blasting can increase the amount of ground support required. Case study data collected by NIOSH in underground metal mines during standard drill and blast production rounds included blast vibration monitoring, detailed three-dimensional laser scanning of the as-built excavation, and geotechnical mapping of development headings.

Jan 1, 2007

By R. A. Bosch, F. V. Lenel, G. S. Ansell

RECENTLY, Ansell and aenel' proposed a dislocation model to account for the yielding behavior of dispersion-strengthened alloys. The criterion for yielding used in this model was that yielding occurs when the shear stress due to arrays of piled-up dislocations fractures or plastically deforms the dispersed second-phase particles. Calculations based on this model predict that the yield strength, uysof a dispersion-strengthened alloy containing particles whose geometry permits them to be considered as straight, i.e. not curved, barriers to dislocations follows the relation where and are the shear moduli of the matrix and dispersed phase respectively, b is the Burger vector of a dislocation in the matrix, A is the mean free path between dispersed phase particles and C is a constant. This yield stress, ys, is closely approximated in polycrystalline alloys by the proportional limit. The offset yield stress, uoy, is the yield stress, uys, plus the increase of stress due to strain hardening in the offset strain increment. Previous investigation1 has shown that Eq. [I] describes the yielding behavior of several different dispersion-strengthened alloys as a function of the mean free path between dispersed phase particles at a constant temperature. The purpose of this investigation was to investigate the temperature dependence of the yielding behavior of dispersion-strengthened alloys. The alloys studied, MD2100 and MD5100, are SAP-type alloys containing flake shaped aluminum oxide particles dispersed in a matrix of commercial purity aluminum. The proportional limit and 0.2 pct offset stress of both of these alloys were determined as a function of temperature over the temperature range from -190" to 500 C. All tests were conducted on an Instron tensile testing machine. Stress was measured by means of the Instron load cell. Strain was measured by means of SR-4 strain gages attached to the tensile specimens. Stress sensitivity was 80 psi. Strain sensitivity was 2 x 10F Fig. 1 shows the values received for the proportional limit and 0.2 pct offset yield stress plotted as a function of homologous temperature for both the MD2100 and MD5100 alloys. Inspection of Eq. [I] shows that of the terms which determine the theoretically predicted yield stress, uy,, only the shear moduli have an appreciable temperature dependence. From Eq. [I] the yield stress at any temperature T, UT, may be predicted from the yield stress at any arbitrary reference temperature, in this case 25 OC, u25, by the relation where the subscripts T and 25 refer to the values of the property at test temperature and at 25"C, respectively. The temperature dependence of the yield stress predicted by Eq. 121, based on the observed value for the proportional limit at 25OC, is also shown in Fig. 1. In evaluating Eq. [2] the following data was used. The values for the shear modulus of

Jan 1, 1962

By D. Argyriades, G. Derge, G. M. Pound

The electrical conductance of molten FeS was studied as a function of temperature and composition. It was found that stoi-chiometric FeS (36.5 pct S) shows a minimum specific conductance of 400 ohm-1 cm-1. For the Fe-rich melts the conductivity increases with increasing amount of iron to about 4850 ohm-1' cm-I at 26 pct sulfur. For the sulfur-rich melts the conductivity increases with increasing amount of sulfur until it reaches a maximum of 1300 ohm1 cm-1 for 37.4 pct S and decreases to 800 ohm-1 cm-1 for 38.3 pct sulfur. It is concluded that molten stoichiometric FeS is an intrinsic semiconductor in which the forbidden gap in the electron energy level diagram is quite narrow. Excess sulfur acts as an acceptor impurity in providing a component of positive hole conduction, while excess iron acts as a donor impurity to increase the n-type conduction. K. Bornemann and G. von Ftauschenplatl used a four-terminal, direct-current cell to study the electrical conductance of molten copper sulfide. Their measurements showed a high conductivity, of the order of 100 ohm-1 cm-" and a positive temperature coefficient. From electrolysis studies, Savelsberg2 concluded that molten Cu2S and molten FeS are electronic conductors. Further. he found that molten FeS has a high specific conductance, of the order of 1500 ohm-' cm-', and a small negative temperature coefficient. Pound, Derge, and Osuch,3 using an ac Kelvin circuit and a four-terminal cell, measured the specific conductance of molten Cu,S, molten FeS, and various mixtures. They found that the specific conductance of the solutions followed a roughly additive rule of mixtures. Yang, Pound, and Derge4 showed from electrolysis measurements that the mechanism of electrical conduction in molten Cu2S, FeS, and mattes is primarily electronic. Further, they observed that small additions of CuCl suppress the electronic conduction whereupon the system behaves ionically.

Jan 1, 1960

By L. Li

The rock quality designation (RQD) was initially introduced by Deere (1963) for civil engineering. But, its application has been largely extended to rock mechanics and has become a fundamental parameter in geotechnical engineering (e.g., Hoek & Brown 1980; Milne et al. 1998). The success of this definition is due, in great part, to its simplicity. However, this index includes a number of limitations. Among these limitations, a critical one is associated with the arbitrarily selected threshold value (e.g., Priest & Hudson 1976). Consequently, the RQD value would vary with different threshold length for the same core. Also, using the customarily and universally adopted but very arbitrarily selected threshold value of 10 cm (for NX cores) in the assessment of RQD, the RQD values usually tend to be either high or low in most rock engineering. Some intermediate values (50%) are less frequently encountered (Harrison 1999). The original definition of RQD does not well represent the actual quality of rock masses. In this paper, an improved definition of rock quality designation (RQDc) is given.

May 1, 2009

By Da Zhao Gu

An important problem in rock engineering is to control the properties of artificial rock. A compaction technique for casting artificial rock specimens with controlled properties is described, i.e. using a compression-testing machine to compress the mixture. Uniform density is necessary to achieve uniformity of properties of the specimens, and uniform density can be obtained by using the specific pressing method presented. Rebound and borax content are important to the technique and have been studied as well.

Jan 1, 1992

The Bureau has published much data on sulfur (4, 15, 23)3, most of it dealing with national or international aspects of the sulfur industry. Little information, however, is available on sulfur marketing in specific States or areas, Therefore, the Bureau has conducted a survey of the resources, production, consumption, and economic future of the sulfur and sulfuric acid industry in States of the Central and Southern Rocky Mountain area - Wyoming, Colorado, Utah, Arizona, and New Mexico - and in the Northern Plains States - North Dakota, South Dakota, and Nebraska, even though these States do not represent an economic or marketing unit. The purpose of this survey is to review the demand for sulfur and primary sulfur compounds that draws upon the natural resources of the region, to discover opportunities for better use of these resources, and also to analyze and evaluate the patterns of consumption, sources of supply, and other factors that affect the demand for these mineral products. While this survey stresses the economic and marketing phases of the industry, a complementary report (32) emphasizes the resources of sulfur in Wyoming, Colorado, Utah, New Mexico, and Arizona.

Jan 1, 1962

By B. Mishra, A. Staley, D. Kirkpatrick

The major waste product of the alkaline extraction of alumina from bauxite [Bayer Process] is known as red-mud. Approximately, a ton of red-mud is produced for every two tons of bauxite mined. The red-mud produced from Jamaican bauxite is rich in hematite, alumina and titanium oxide. It has been shown that over 90-wt. pct. alumina can be recovered from red-mud by soda-ash sintering and caustic leaching. Hematite can be carbothermically reduced with a degree of metallization of over 94 pct resulting in attempts for magnetic separation. These separations are desirable in the notion that there is no waste product generated from this type of processing and consequently an opportunity for complete utilization of the waste material. Conversely, the pre-separated material could be charged through the tuyeres in an iron blast furnace or smelted to produce pig iron. If smelted, the concentration of titanium oxide in the slag will be significantly high justifying its recovery by established acid-leach process. This paper describes the results of alumina recovery and the plans for titanium oxide recovery from red-mud. In addition, the situation of ongoing efforts in iron extraction, particularly, the method of magnetic separation of the reduced material. The problems associated with the use of reduced red-mud as an alternative to direct-reduced iron [DRI] has also been discussed. Critical assessment of the recovery sequence chosen for the products has been described based on economics.

Jan 1, 2001

By J. A. Lamonica

The Bureau of Mines conducted an environmental noise survey to determine the noise levels to which underground coal mine employees are exposed, to evaluate noise survey techniques and equipment, and to compare noise exposures using two criteria, Walsh-Healey and CHABA, for determining allowable exposures that were under consideration for the Federal Coal Mine Health and Safety Act of 1969- Time study techniques and Bureau-approved standard sound level meters were employed. The shift exposures of 20 percent of the miners studied were in excess of the safe standards established by both criteria. The shift exposures calculated using the Walsh-Healey criteria were greater than those calculated using the CHABA criteria owing to the intermittent nature of the exposure. Ultimately the CHABA criteria were rejected, and the Walsh-Healey criteria were adopted.

Jan 1, 1971

By W. P. Tassie

"The location of Quintette Coal Limited's pit and geologic nature of the dedicated reserves combine to introduce a number of factors which can adversely affect waste dump stability. These factors include steep terrain, variable material type and particle size, and precipitation. This paper describes the solutions to related waste dump problems. A brief geotechnical review of the waste dumps is given and Quintette's operational strategies during periods of dump stability and instability are discussed. Despite best efforts, failures occasionally occur and discussion is included on Quintette's success at bringing failed dumps safely back into use. IntroductionQuintette Coal Limited (QCL) property is situated on the east slope of the Rocky Mountains near Tumbler Ridge, approximately 120 km southwest of Dawson Creek, British Columbia. This surface mine is located on mountainous terrain and is subject to climatic extremes of wind, precipitation and temperature.QCL has a current annual production of 4.75 million tonnes of metallurgical coal with a stripping ratio of 7: 1. This correctly implies the extraction of over 33 million bank cubic metres (BCM) of waste which is placed on numerous waste dumps at various locations adjacent to the pit.There are three active pits - Mesa, Wolverine, and Shikano (Fig. 1). Shikano is a newly developed pit located near the plant site. It is not subject to the unique dump management problems prevalent at the Mesa and Wolverine pits, therefore the Shikano waste dumps will not be discussed . The dumps for the Mesa and Wolverine pits, however, have been technically and operationally challenging since shortly after mining began in 1983. Their characteristics, associated site specifics and management, therefore, are the subject of this paper.Waste dump locations for the Mesa and Wolverine pits are shown in Figures 2 and 3 as is the relative waste distribution . Each sub-pit is connected to a principal waste dump in reasonable proximity and to an alternate dump should disposal of waste be necessary at that location. The waste dumps are constructed from the top elevations initially to coincide with subpit development. In the initial years (1-7) waste dump heights will be up to 250 m, then, as the mine matures (8-20 years), waste dump maximum heights will continuously decrease to coincide with lower bench elevations"

Jan 1, 1988

By A. F. Raschenko, Y. A. Golodcov, V. V. Elshin

"The autoclave noble metal desorption in apparatuses with a dense stationary sorbent layer is perspective for the technology of sorption gold and silver extraction from solutions and pulps by carbon sorbents. The study of the mechanism and optimization of the autoclave desorption process involve some difficulties. To overcome them it is necessary to use mathematical and quantum-chemical modelling. The given paper deals with a mathematical model for the dynamics of gold and silver desorption from active carbons by alkali solutions based on the physical-chemical notions of the process. The kinetics and the mechanism of the process were investigated using the mathematical model for gold and silver desorption.The calculation of the efficient mass-transfer coefficient (ße) for various initial and intermediate noble metal concentrations in carbon (Cy) made it possible to find that the dependence of ße on Cy in case of gold desoprtion shows a clear extreme character. The value of the initial metal concentration in carbon therewith does not influence the character of the curve the inflection point of which is changed essentially at elevated process temperatures only. The revealed characteristic property, in the author's opinion can only be indicative of the change in the mechanism of gold desorption under autoclave desorption conditions. The assumed [Au(CN)(OH)]- type intermediate that has a higher diffusion coefficient in comparison with the adsorbed complex [Au(CN)2]- can be considered as an intermediate compound in the process of gold desorption."

Jan 1, 2003

By Wojciech Klecan

Cobb County, located on the northwest side of Atlanta, GA, is continually growing and, like many other metropolitan areas, it needs to increase the capacity of its waste water system to meet future demand. The Cobb County Water System (CCWS) is the responsible agency for water distribution, waste water collection and treatment in most areas of the county. CCWS, one of the most progressive agencies in the metro-Atlanta area, is addressing its future waste water capacity needs in the southern part of the county with the construction of the South Cobb Tunnel and Pump Station. This project consists of an 8.8-km- (5.5-mile-) long, 8.2-m- (27-ft-) diameter, tunnel boring machine (TBM) excavated waste water storage and conveyance tunnel; six tangential vortex-flow intakes ranging from 1,533 to 5,700 L/s (35 to 130 mgd) peak flow capacity, two construction shafts, six 1.8-m (6-ft) finished diameter connecting tunnels ranging in length from 6 to 975 m (20 to 3,200 ft) and a 5,700-L/s (130-mgd) wet/dry pit pump station. The pump station will have a semi-circular wet well with a dividing wall that extends almost to the top of the shaft and a spilt dry well for reliable operation. Roller gates will control the flow to the wet well from the tunnel. The pump station will have six 1,420 L/s (32.5 mgd) pumps and two sets of stair wells and elevators. With a finished diameter of 32 m (104 ft) and a depth of 62 m (204 ft), this is the largest pump station shaft constructed so far in Georgia for the dewatering of a waste water tunnel. The pump station shaft was also the highlight of the well attended and successful 2009 Shaft Design and Construction Short Course held in Atlanta, Sept. 10-11. The two-day course was sponsored by the Underground Construction Association of SME and Pennsylvania State University and concluded with a field trip to the pump station shaft. The tunnel starts south of the city of Austell and finishes at the South Cobb Water Reclamation Facility (WRF), located on the banks of the [ ] Chattahoochee River just north of Interstate 20 (Fig. 1). The South Cobb Tunnel will run 30 to 137 m (100 to 450 ft) below the surface, with an average depth of about 91 m (300 ft), through metamorphic rocks (Fig 2). The construction contract was awarded to Shea-Traylor JV with the lowest bid price of $305 million and notice-to-proceed was given on July 14, 2008. Jordan Jones & Goulding, Inc. (JJG) is the project designer and performed the geotechnical investigations. Parsons/Jacobs Associates is the construction manager. The South Cobb Tunnel is CCWS?s second deep hard rock tunnel. The 15.3-km- (9.5-mile-) long, 5.5-m- (18-ft-) diameter TBM excavated the Chattahoochee Tunnel was the first deep tunnel to be construced in Cobb County. Construction began in 2000 and the project was completed four years later. It is located about 16 km (10 miles) northeast of the South Cobb Tunnel in similar geology. It was designed by JJG to meet east Cobb?s long-term waste water capacity needs and provide flow equalization to the R.L. Sutton WRF. The Chattahoochee Tunnel was named ?Outstanding Civil Engineering Project of the Year? by the Georgia Sec-tion of the American Society of Civil Engineers in 2006.

Jan 1, 2009

By Alan Galley

CMIC Mandate CIM Annual Meeting, Toronto, May 6, 2013 To increase mining research, innovation and commercialization efforts in order to strengthen Canada?s pre-eminent role as a global leader in mineral exploration, mining and knowledge-based services and technologies. To increase the supply of highly qualified graduates from mining and earth sciences faculties to meet the significant demand today and into the future of industry, governments and academia. The CMIC initiative is intended to develop long term research strategies that extend five or greater years. Such a research plan will underpin fundamental research and innovation and the training of HQP

May 1, 2013

By Gordon F. Scott

This paper considers a recently completed hoist project for IAMGOLD. Called the Westwood project, this mine utilises some of the largest drum hoists supplied to the North American Market in recent times. This project is an example of where many of the design features discussed the associated paper, (Robotham, 2011) were incorporated. Director of sales and marketing, Gordon Scott has worked at DavyMarkham for over 30 years in a variety of roles starting as a mechanical design engineer, moving to project management before joining the sales department. Gordon has an honours degree in mechanical engineering from Leeds University.

May 1, 2011

By Robert F. Randolph, Jeffery L. Kohler, David C. Byrne

Multiple versions of an educational message can reach a diverse population more effectively than a single version. For instance, some workers are trained in formal classrooms while others are self-taught. The National Institute for Occupational Safety and Health has developed multiple versions of a hearing loss simulator (an interactive software package, a Web-based module, and an electronic slide show) to show how a single set of information can be readily adapted to different delivery methods. The three versions of the simulator were developed with a minimum of effort and expense compared to a single, less-flexible version. The interactive software is best for training sessions led by a hearing conservation professional, the Web pages are best suited for an individual worker, and the slide show is best for a small, more-generalized, training class. This paper will describe additional advantages and disadvantages of different delivery systems and will show what considerations are helpful in designing content that can be readily adapted to alternate presentations.

Jan 1, 2002