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By James R. Arnold, Timothy D. Arnold

The mathematical rigor of the collegiate engineering experience prepares an engineer well for the technical aspects of his or her career. However, as that engineer progresses in the industry, how well does he or she do as a manager? The exacting, detailed, and complete problem-solving process that engineers are trained to use sometimes conflicts with the nimble, rapid decision-making process required in the dynamic world of business. This paper discusses the topic of "engineers as managers.”It will investigate the personality traits of engineers relative to the traits of successful managers, and provide specific details about how well engineers have done in the field of management.

Jan 1, 2001

By M. Abdi Oskouei

Some believe that Sustainable Mining due to impermanence of mining operation and adverse environmental impacts of mining, is an oxymoronTruly, no one can overlook these environmental impacts; however, a sustainable development is based on three elements Environmental, economical and social sustainability. In order to assess the relation between mining activities and sustainable development, not only environmental but also economical and social sustainability must be considered.Thanks to mine reclamation the adverse impact of mining on the environment can be reduced, meanwhile it will improve the social and economical condition after the mine-closureTo ensure that a mining operation is toward sustainable development goals, specific criteria and indicator frameworks have been established, in addition, for verification of our discussion the suitable selected reclamation plan for Bibishahrbanoo limestone mine of Tehran-Iran and its effect on sustainability of region has been studied.

Jan 1, 2011

By P. Mousset-Jones, F. Calizaya

Ultrasonic anemometry is a relatively new method of measuring the air velocity in underground excavations and is not widely used. The method has been mainly used for surface applications, such as meteorology and fluid flow measurement. Several instruments were looked at to determine their applicability for continuous underground monitoring systems. The units fall into two main categories: variable distance units and fined distance units. The method relies on the acceleration and deceleration of ultrasonic pulses transmitted through a moving airstream. This study presents some of the results of the testing of variable and fixed distance ultrasonic anemometers in a wind tunnel and a mine drift.

Jan 1, 1995

By P. J. Kientzler, Y. C. Lo

The current study is concerned with the analysis and attempt at simulating the product size distributions obtained from a vibrating ultrasonic device. Systematic experiments of comminution were performed with natural sizes as well as monosizes in order to understand the breakage behavior of the device. A precise analysis of the device's breakage performance in the case of fine grinding of alumina samples will be presented. Initial steps to model the breakage events using a detailed mathematical algorithm will be discussed.

Jan 1, 1992

By James G. Sampson

The discarded phosphatic clays from mining operations have historically been stored behind earthen dams for long periods of time before any reclamation was accomplished. In efforts to expedite the dewatering and reclamation of the clay ponds, the phosphate industry explored alternatives to conventional clay disposal practices. One alternative, employed by CF Industries, Inc., combines the clay and the discarded sand prior to disposal behind earthen dams. The sand encourages the clays to 'give up' trapped water more readily resulting in enhanced consolidation behavior. This paper provides an overview of the sand-clay mix process including the reclamation of sand-clay disposal areas.

Jan 1, 1992

By T. C. Rao

The quantum of coal fines below 6 mm in run-of-mine (ROM) coal has been increasing due to progressive mechanization of mining methods which has created a substantial incentive, worldwide, to develop suitable fine coal beneficiation techniques. The majority of the efforts have been directed toward reduction in ash/sulfur contents in clean coal. The beneficiation techniques may be broadly grouped as those based on specific gravity and surface property. The processes, which use heavy medium cyclone, water-only cyclone, concentrating tables, and spirals, belong to the former group while the latter group encompasses froth flotation, column flotation, oleo- flotation, and oil agglomeration. In almost all the gravity based techniques, it has been noted that a classification step prior to beneficiation is essential for effective treatment. In general, the effect of design and process variables on the performance of these units and also the quantification of the processes have been the main areas of research and development. In froth flotation, efforts throughout the world have been mainly to understand the effect of variables and to optimize the process. Quantification of the process has been attempted through kinetic studies and mathematical modeling. The efforts have led to the development of new reagents, machine designs, and flowsheets for a specified objective. The attempts so far with the column flotation and oleoflotation processes have indicated a great potential. Extensive R&D efforts are in progress to understand as well as to commercialize the processes. The efforts in the oil agglomeration process have been toward substantiating the inherent merits of the process by developing cheaper bridging liquids and technology to recover and reuse the oil to make the process commercially viable. Modeling of the process has also been attempted to predict the yield and size distribution of the agglomerates. This paper reviews and summarizes the recent developments in the science and technology of fine coal beneficiation processes. The current trends in R%D efforts for these processes are also highlighted.

Jan 1, 1987

By P. Somasundaran, D. R. Nagaraj, Jing Wang

Polysaccharides have been widely used as depressants in mineral processing for decades. They constituent one of the most abundant family of biopolymers. However, only a small number of them have been used by industry so far because of a general lack of understanding of interactions between these polymers and minerals. In this work, adsorption tests, electrophoretic mobility measurements, microflotation and fluorescence spectroscopic tests were performed along with computer simulation to explore the mechanistic aspects of guar gum adsorption and conformation on talc as a function of relevant variables such as ionic strength, pH, solvent composition and polymer molecular weight. From microflotation tests, it was found that talc hydrophobicity decreased markedly due to the adsorption of guar gum even at very low concentrations and reached a plateau below moximum adsorption. Guar gum adsorption on talc was found to be not affected significantly by changes in solution conditions such as pH and ionic strength, ruling out electrostatic force as controlling factor for adsorption. Fluorescence spectroscopic studies showed no evidence of the formation of hydrophobic domains at talc-aqueous interface. Also urea, a hydrogen bond breaker, reduced the adsorption of guar on talc. All of the above results suggest that one of the main driving forces for guar adsorption on talc is hydrogen bonding in preference to electrostatic or hydrophobic force. This information should help toward designing reagents of optimum molecular architecture for efficient depression, dispersion or other such surface modification of particles.

Jan 1, 2005

By Joel K. Witt, Jackson G. Jenkins, Wendy M. Gort, Brent A. Whitman

A major concern for operators of leaching/SX-EW plants is a phenomenon known as gunk or crud. The build up of gunk is typically the result of fine particulates which are transported via the leach operation to the solvent extraction plant. The particulates develop into a solid layer that concentrates at the aqueous/organic interface. This can cause phase separation problems which can result in entrainment and other deleterious operating conditions. Most operations physically remove the gunk from the SX settlers and process it via a centrifuge or coalescer to remove valuable organic. While both methods have served for many years, Magma is currently evaluating the use of a chemical surfactant which induces a definitive separation of particulates from organic.

Jan 1, 1994

By W. H. B. Blackburn, D. M. S. Bhatia

Twenty-six in situ analyses of cubic galena crystals from a Mississippi Valley-type deposit were undertaken with a laser microprobe emission spectrograph to study the variation of nine trace elements from the crystal center to its periphery, both along the diagonal and vertical. The general trend is an outward increase in the concentrations of Ag, Ga, Ge and In, with As showing the opposite trend. Bi, Cd and Sn showed no discernable trends. Sb was not detected. These variation patterns may serve as a model for similar studies of other Mississippi Valley-type deposits.

Jan 1, 1987

By Odin D. Christensen

Gold deposits of the Carlin Trend occur within sedimentary rocks deposited across the Paleozoic continental margin. Lithologically dissimilar units, juxtaposed along the Roberts Mountains Thrust Fault system, constitute three distinct stratigraphic packages: autochthonous miogeoclinal carbonates, allochthonous eugeoclinal siliciclastic rocks, and an overlying coarse clastic overlap assemblage. Gold deposits occur within all three stratigraphic packages, with economic concentrations localized at structural and stratigraphic settings similar to those which host petroleum traps. Along structural breaks, gold is selectively concentrated within favorable stratigraphic units. Host stratigraphy controls the character of the ore, including average grade, grade variability, physical properties and metallurgical response.

Jan 1, 1989

The new generation of computer environment provides mineral processing plants with convenient tools to store and retrieve or to analyze on-line process variable values as given along time by the various sensors installed in the plant. The paper describes the application of classical tools, such as time series analysis, to retrieve the hidden information contained is such data. The concepts used in single signal processing (autocorrelogram, power spectrum, ARIMA descriptors) and multi-signal processing (cross-correlogram, cross-spectrum) are briefly reviewed. Some examples are given to illustrate their application (sampling, data filtering, process behaviour prediction, process evaluation, data synchronisation). Examples are taken from mixing, flotation and leaching processes.

Jan 1, 1990

By Michael D. Balen

The plate-glass windows in the bus were cracked and mud-coated. Nevertheless, they afforded an excellent view of the many head-on collisions we narrowly avoided along the route from the Magadan airport to town. Apparently the driver thought the left side of the road was smoother than the right side, for he drove in the wrong lane at all possible times, even in the face of oncoming traffic. As far as we could tell, neither side of the road was any better than the other. Either way, we had to hang on just to stay in our seats. We careened past trucks and pedestrians, nearly always in the face of impending disaster. When the bus finally pulled into the parking lot of the Okean Hotel in Magadan, we had to thank the driver, not only for safely delivering his passengers, but also for the lasting first impression he gave us of the Russian Far East.

Jan 1, 1995

By J. W. Markham, M. Atiemo, K. Yoshida

INTRODUCTION In open-pit mining of high grade ores, operators of mining equipment in a pressurized cab are protected from inhaling radioactive aerosols by the use of filtered air through a pre-impactor and a HEPA (high efficiency particulate air) filter. At present, a limited amount of scientific information is available on the worker exposure to airborne alpha emitters in the mining of high-grade ores. (Miller, 1977, Nielson, et al, 1979). Factors affecting the worker exposure to alpha radiation are: the grade of uranium containing ores, the environmental conditions inside the mine pit, the protection factor of the cab filter system, the workers' attitude towards the hazards of radioactivity and the adopted contamination control in the cabs. Four series of field samplings were conducted during the fall of 1980 and the summer of 1981 at a mining site in northern Saskatchewan to investigate the extent of protection an equipment operator has against cab internal exposure to airborne alpha emitters with short and long half-life radionuclides. The variation in the breathing zone concentrationnof aerosols as a result of resuspension is discussed, however no attempt was made to isolate and investigate the factors and the associated parameters of the aerosol resuspension phenomenon. AEROSOL RESUSPENSION IN A CAB Mechanisms of Resuspension [Sources]: The presence of radioactive aerosols inside a cab and in the breathing zone of an operator may be due to initial concentration inside [(CO)], concentration in the filtered (HEPA) air (CC, at the flow rate [QC]), the concentration of the aerosol through resuspension ([CR]), the aerosol concentration in the air outside the cab ([CE]) and the concentration of the aerosol in the leaking air [(CL)], at the flow rate of [(QL)]. [Volumetric Equilibrium]: Assuming a uniform concentration of the aerosol in the cab, the aerosol concentration in the breathing zone[ (CBZ)] may be expressed as, [CBZ+CO+CC+CR-CL] If [QC] remains greater than [QL], there is pressurization in the cab. There is particle loss as a result of the leaking air from the tight cab, however the condition of adequate pressurization ensures that [CL ~ CC]. Also for dust particles filtered through HEPA [CC – 0] thus [CBZ + CO + CR] For the radioactive gases, [CBZ - CO + CC] Over long periods,[ CBZ – CE] but if [CBZ] exceeds the value of CE then the aerosol build-up in the cab has, occurred. [Resuspension]: Turbulent bursts are generated within the core region of a cab confinement, such that the down sweeps and the up sweeps of the air bursts cause resuspension of dust from the surfaces. Particles initiate resuspension by four major modes: namely, sliding, rocking, rolling, bouncing or sudden ejection or by combinations of these. Nevertheless the adhesion force between the particles and the surface must be overcome by ejection forces before ejection takes place (Kline et al, 1967, Corino and Bradkey 1969, Kim et al 1971). The phenomenon of particle resuspension from a surface may be expressed in a generalized form as: CR =f (Uz . R . D . H) where CR = Rate of particle resuspension UZ = Surface shear velocity R = Surface roughness parameter D = Aerodynamic diameter of particle H = Frequency of surface airburst A detailed discussion of the individual parameters was attempted for the case of farm tractor cabs by Atiemo (1981), such a treatment is out of the scope of this study. Only the effects of the properties of surface roughness will be discussed. Effect of Surface Properties The roughness of the surface from which dust particles are ejected plays a significant role in the deposition and resuspension of the dust. The roughness or the amount of protrusions greatly influence the intensity of air turbulence in the immediate vicinity of the surface (Schmel 1976). For most roughened surfaces therefore, larger particles may be dislodged in greater quantities than smaller particles. The deposition and the resuspension of dust particles from different surface materials of glass, cloth, metal and rubber have been studied in a wind tunnel (Atiemo, 1981). Field Conditions Mining equipments used are: a backhoe, a bulldozer with ripper attachment and two dumptrucks for high-grade ore operations; a payloader and two dumptrucks for waste handling; and a jumbo drill which drills dynamite holes for ore blasting. All this

Jan 1, 1981

Geopolymerization is a process by which Al-Si minerals undergo dissolution and polymerization in an alkaline solution to form a monolithic material with a high mechanical strength (Davidovits, 1991, 1994). In this study, the factors affecting the geopolymerization of Na feldspar (albite) and K -feldspar (microcline) were investigated. It was found that both Na feldspar and K -feldspar are reactive in geopolymerization with the resultant geopolymers showing a high compressive strength. The leaching ability, the proper molar ratio of Si/Al in the geopolymeric gel phase and the higher average hardness of the undissolved particles remaining in the geopolymers are found to greatly affect the ultimate compressive strength of the formed geopolymers. Key words: Geopolymerization, Mineralogy, Albite, Microcline

Jan 1, 2003

By Simon D. Handelsman

Technical co-operation activities of the Department of Technical Co-operation for Development of the United Nations Secretariat have included the introduction of electronic data processing techniques in mineral sector projects for several years; computers have been provided to countries in Africa, Asia and Latin America. Advisory services are provided to interested developing countries at their request concerning applications for various uses in mineral sector activities. They include advice on appropriate hardware and software depending upon the requirements of the particular Government. The Department's activities in this area are described. The input from a Group of Experts on this subject convened by the United Nations, and their conclusions and recommendations, are also discussed.

Jan 1, 1986

By H. L. Bourne

This paper describes six basic stages between perception and production for a new sand and gravel deposit. Sand and gravel, like many of our natural resources, is taken for granted. It is assumed by John Q. Public that because sand and gravel is ubiquitous that it is available whenever and wherever needed - so long as it does not have to be mined in his neighborhood. This idea illustrates one of the enigmas of the industry, the fact that sand and gravel is abundant; however, its availability is another matter. Another problem is that this resource falls in the category of high volume, low profit materials; therefore, transportation costs are critical. Transportation roughly doubles the cost of these materials. It is not difficult to find sand and gravel, at least in Michigan. The problem is to locate a new source close to a market, near an adequate transport route (usually a highway) and in an area which will allow mining.

Jan 1, 1970

By Zvonimir Jam?ek

In Rudarski Institut Ljubljana (RIL), i.e. Ljubljana Mining Institute, we have developed CADRIL, a smaller CAD package which purpose is to overcome the difficulties by introducing Computer Aided Design in our mines. Program CADRIL is a graphics shell for several computer applications in mining. With the basic version of CADRIL all 2D working maps for daily use can be produced. Inserting different program blocks into CADRIL we get versions MAPRIL, TAHRIL, SECRIL and so on. The main purpose of all versions is graphics design. The main and most innovative feature of CADRIL is the screen four-word command menu. Not having pull-down or tablet menus is the speciality of this program. CADRIL contains 500 achievable commands. Each of them can be composed by choosing two to four expressions stored and shown in a specific four- column menu, sorted as objects functions, parameters and modes. Thus all commands are immediately accessible. As a result of its plainness and adaptability to the present working methods of mining engineers, CADRIL quickly attained a good reputation in our mines.

Jan 1, 1992

By B. K. Baird, P. C. Satchwell

The application of cutoffs during and after pit optimization is examined for a lower-grade multi-metallic copper deposit. Pit optimization requires calculation of the net revenue associated with each mining block, incorporating parameters such as metal prices, grades and expected recoveries, mining and processing costs, smelting and refining charges, and penalty element and royalty charges. Sensitivity analysis during pit optimization reveals which of these parameters have a significant effect on the total contained resource tonnage and total contained non-discounted revenue in the optimized pit. The cumulative effect of changing several of the more significant parameters is investigated. Application of a copper cutoff grade to a block inside the optimized pit could result in the less than optimal extraction of the resource. A block with copper grade below the applied cutoff could be economic due to the presence of other metals. Conversely, a higher copper grade block may be sub-economic. The relative merits of applying a copper grade cutoff, “equivalent grade” cutoff and dollar value per ton cutoff to blocks inside the optimum pit are discussed.

Jan 1, 1999

By K. Koizumf, A. A. Cram, K. Whitchurch

The Expert Scheduling is a new, exciting method for scheduling underground and open-cut coal mines. A key feature of the Expert Scheduler is the adoption of an expert or artificial intelligence system. The expert system makes decisions regarding the schedule, such as which area should be mined. With existing scheduling systems these choices are made by the scheduling engineer. Developing one area may be better than another if it offers better quality or lower costs. Information the engineer considers in these decisions could be; • coal tonnage and quality targets, • equipment utilisation, • mining cost, • and other practical constraints. In expert scheduling a number of experts are appointed to make these decisions. A number of mining strategies are examined for each period. Information for each strategy is evaluated by "experts" and the "best" solution adopted. The method is based on the Blackboard Techniques. With this technique information is presented to "knowledge sources” or "experts" by the Blackboard Controller for their "opinions". These "opinions" are examined by the Blackboard Controller to select the best strategy. Engineers can readily add experts to the system, and modify the weighting of experts to suit mining conditions. Using an Expert Scheduler means that many schedule op- tions can be analysed quickly with full repeatability.

Jan 1, 1996

By Tad S. Golosinsk

Use of computers for hoist evaluation and design dates back to the early 1960's. Mine hoist production calculations, repetitive in nature, were computerized first. More elaborate modeling of hoist operations followed soon. Typical for this, early period are the models described by Touwen (1973), and by Albert and McIvor (1984). Apart from the simple hoist production calculations, the models were very complex, typically written in Fortran, and often required advanced computing facilities and expertise to run the simulation. The early models were strictly deterministic, with no consideration given to the random nature of hoisting operations. The effects of randomness of the hoisting process on hoist performance were often accounted for by introduction of the deterministic factors, most notably of an "utilization factor" related to the hoist production. The value of the latter was based on observations of actual hoist performance, and could vary in a wide range. For example Harvey (1973) reports values of the "utilization factor" to be between 0.7 and 0.92.

Jan 1, 1989