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By R. W. Fedors, S. T. Green, F. T. Dodge, D. B. Walter

Spatial and temporal temperature variations in a high-level radioactive waste repository drift can give rise to moisture transport within the drift. Knowledge of this moisture transport may be important to assessing the potential for corrosion of all metallic components in the drift. The model presented here shows one approach to simulating evaporation, transport, and condensation of water in large underground openings using a framework based on computational fluid dynamics. Simulation results that explicitly model water and latent heat transport are presented.

Jan 1, 2004

By Paul D. Tomlingson

There are huge benefits for mining operations that have a well-defined maintenance program that is understood and followed across the total operation. But for operations lacking a quality maintenance program, there is equal assurance that nearly every major maintenance problem can be traced to this omission. Few problems will be permanently corrected until such a program is implemented. Definition The maintenance program re-quires the interaction of all mine departments. Initially, the production department will request work and the maintenance department will identify work, principally through preventive maintenance inspection and testing efforts. Maintenance will then classify the new work to determine the best way to respond. Maintenance will plan selected major jobs to enable its crews to carry them out more effectively. Maintenance will schedule the planned work with operations. Supervisors will assign all types of work to their crews then, control the work through effective supervision. As work is completed, maintenance will measure the work using an accurate information system. Next, it will assess overall accomplishments against goals such as performance standards or budgets. In addition, the pro-gram would prescribe a means to evaluate every aspect of the operation as it affects maintenance so that necessary improvements or changes can be identified, prioritized and acted on. Such evaluations should be part of a mine-wide continuous improvement effort. A well-defined maintenance program is one of the best investments a mining operation can make to assure its profitability. Educating the total operation on the pro-gram assures long-term dividends from the investment.

Jan 1, 2008

By M. Javier

Defining the concept of sustainability is an important step for industry and society. It is necessary in order to clarify what it means when debunking the many misinterpretations pervasive in different levels of anthropogenic activities. Essentially, the extractive industry has a harvest of differences. Mining involves the extraction of natural resources which are finite, exhaustible, non-renewable, unsustainable, and pay only once. It is remarkable that the definition of sustainability that we will shortly arrive at has totally different characteristics from the definition accepted throughout society. We categorize nature as having its own destiny which is controlled by its own rules and principles and its own society, and is part of nature; therefore, society depends on nature and not vice versa as the initial focus. To society there are no conditions to humanize nature but only respect nature?s rules. It was a challenge to find simplicity for this task not only for the definition but also for the explanation of this concept specifically, to answer the question, ?what is the true meaning of sustainability?? Finally, we are also able through this definition to provide fuel for wide discussions and stimulate critical thinking to improve such a concept. As a result, we present this definition as the tool for society today and for future generations.

Jan 1, 2012

The Mining Foundation of the Southwest will host its 24th Annual American Mining Hall of Fame Awards Banquet at the Tucson El Conquistador Golf & Tennis Resort in Tucson, AZ on Saturday, Dec. 9. The Mining Foundation of the Southwest is a non-profit organization whose objectives are public education about the mineral industries. It also recognizes outstanding accomplishments in and contributions to the fields of fuel and mineral resources.

Jan 1, 2006

By C. S. Kucukkaragoz

An ilmenite concentrate was reduced in the solid state with carbon under argon atmosphere at temperatures between 1000oC and 1400oC. The ilmenite concentrate and 50% excess carbon were reacted to achieve the highest attainable degree of reduction at each temperature and the reaction products were subjected to a series of analytical work by optical microscopy, X-ray diffraction analysis and SEM ( EDS) analysis. The ilmenite remained unaltered at 1000oC and had a slight change in its composition at 1050oC. A secondary oxide phase containing metallic nuclei was detectable at 12% reduction at 1100oC. The reduction of TixOy took place in a sequence changing the y/x ratio from 2.0 to a value less than 1.0 at 84% reduction at 1400oC. Metallic phase consisted of Fe and C initially and started to include Ti at the later stages. Complete reduction of TixOy to metallic Ti was not possible at these temperatures.

Jan 1, 2005

Flawed mining studies have been major contributors to poor investment decisions in mining for many years, contributing to the long period of poor industry profitability. Most of the major mining houses have now adopted quite formal processes and quality standards for mining studies to reduce the potential for poor investment decisions in the future. Other organisations such as the World Bank also have specific requirements for particular types of studies, such as bankable studies. This increasing requirement for rigour and discipline means a highly structured and phased sequence of studies is now required along with the development and adoption of industry-wide standards in mine ventilation studies. New terms in the study process such as ?independent peer review? and ?hold and review? are assisting in this process. More traditional terms such as ?feasibility study? and ?pre-feasibility study? now have much more precise technical definitions. Specific standards for the ventilation components of the various phases of a mining study are proposed in this paper.

Jan 1, 2009

By A. Bascetin

Waste materials caused by mining activities are an important environmental problem. Paste technology is a good alternative for waste management because it has many benefits in the aspects of environment, cost and safety. Disposal of process wastes in paste form is an attractive option for waste management, as it eliminates or reduces the risks associated with conventional methods. Due to the geotechnical characteristics of the paste, it is very similar to soil materials. So determining the geotechnical properties of the paste material is essential to durability of the paste. The some important geotechnical properties are compressive strength, porosity, shear strength, hydraulic conductivity, water content, consolidation, etc. In this study, the important parameters and the relation between them were investigated and obtained some results which will affect for optimum design of waste management.

Jan 1, 2012

By S. Chander, S. W. Musselman

The molecular structure of hydrophobic and hydrophilic groups in nonionic surfactants has been related to the wetting and dispersion of selected pigments. The nonionic surfactants included in this study are acetylenic diol based surfactants and ethoxylated alkyl phenols. The Langmuir model could be used to fit adsorption data. Further analysis of the data showed that the free energy of adsorption was a function of adsorption density of the surfactants at the interface. The change in free energy with adsorption density could be interpreted by considering a change in the orientation of the adsorbed molecules. Acetylenic diol based surfatants were found to have an area per molecule of 2-3 times that of similarly ethoxylated alkyl phenols. The wetting and dispersion properties of lamp black, a model hydrophobic surface, by these surfactants were investigated by contact angle measurements and particle size analysis. Acetylenic diol based surfactants with ethylene oxide contents between3.5 and 10 moles per molecule and alkyl phenol based surfactants with approximately 9 moles of ethylene oxide per molecule were found to provide superior wetting abilities. Longer ethylene oxide chains were required for superior dispersion capabilities within each family of surfactants. Complete wetting and dispersion was found to occur above the critical micelle concentration of the surfactants.

Jan 1, 2000

Mine planners must select a single pit for design with the knowledge that the grades on which this selection is made are uncertain. This uncertainty is often ignored through the use of deterministic models of grade. This makes the mine planner?s job simpler but does not necessarily lead to the ?correct? or ?best? selection. Grade uncertainty is typically modelled with conditional simulation which generates multiple possible realisations of grade that are equally probable (or improbable) to occur. Methods for incorporating grade uncertainty into mine planning to date have either been perceived as being too complicated, not accessible or too time consuming. This paper proposes a simple and efficient modelling approach to incorporating conditional simulation into pit optimisation, which would be able to be applied in currently commercially software. An example for Resolute Mining Ltd?s Syama Gold Project in Mali shows the range of ore, grade and value outcomes associated with generating pits through a variety of methods.

Feb 27, 2013

By M. Prud’Homme

Potash is an important natural mineral used largely as a fertilizer in the production of food and fiber. About 93 percent of all potash consumed globally is used in agriculture as fertilizer. The balance is used to manufacture potassium chemicals. Most potash is extracted by conventional underground mining methods. Solution mining is used when underground deposits are irregular and very deep. The other main production method involves the evaporation of brines in shallow salt lakes, followed by the harvesting of potassium minerals.

Jan 1, 2005

By Carmel Bofinger, Maureen E. Hassall, David Cliff, Eric Stemn

e Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

By Carmel Bofinger, Maureen E. Hassall, David Cliff, Eric Stemn

e Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

By B. T. Mirabile, D. Tang, Y. Luo, S. S. Peng, C. T. Holland

Knowledge of local coal mine roof geology is critical to the design of a safe and suitable mine structure. An automated drill control and data collection system has been designed for a J.H. Fletcher twin-head roof bolter. Drilling parameters collected during the drilling process can be used to interpret geologic features intercepted in the mine roof. The drill and data collection system have been tested in both laboratory and underground settings. Visualization of certain drilling data has shown good correlation with geology drilled. A quantitative prediction model was developed using drilling parameters examined with data visualization. The quantitative model was tested using laboratory drilling data.

Jan 1, 2004

By Steven J. Van Kauwenbergh, Talaat A. B. Lawendy

Batch laboratory-scale beneficiation tests were conducted on four high-iron phosphate samples. These samples included sedimentary ores (Tilemsi Valley, Mali and Tahoua, Niger), a sample from an igneous phosphate deposit (Matongo, Burundi), and a fine-grained phosphatic iron ore processing residue from Chile. The Matongo phosphate deposit occurs as a thick (up to 80 m) residual blanket of P205-enriched soil over solid parent rock (carbonatite and associated rock types). Although the Matongo deposit is an igneous deposit, ore from the deposit can be subjected to beneficiation treatments commonly used to treat sedimentary rocks. The beneficiation flowsheets designed to process these diverse ore types involve attrition scrubbing, size classification, and flotation. At the best flotation conditions tested, phosphate concentrates assaying 32.0%-39.0% P205 and 1.0%-1.5% Fe2O3, were obtained at 64.2%-82.2% overall P2O5 recoveries from run-of-mine (ROM) ores containing 9.2%-28.6% P205 and 5.9%-16.1% F,20,. A cleaner phosphate concentrate assaying 33.1% P205, 1.8% A1203, and 3.3% Fe2O3 at 53.4% overall P205 recovery was obtained from the phosphatic iron ore residue that originally contained 4.5% P205, 8.0% A1203, and 17.6% Fe2O3.

Jan 1, 1993

By John B. Jones

New concepts in shaft kiln processing are included in the design of two large diameter shaft kiln plants now under construction. One kiln will be used to produce cement clinker at the Boettcher plant of the Ideal Cement Company at Fort Collins, Colorado. The other kiln is for the semi-commercial oil shale plant for Petrobras, the Brazil National Oil Company at Sao Mateus do Sul, Parana, Brazil. Investigations on application of the new concepts are proceeding in a portable pilot kiln. The shaft kiln has long been recognized as a method of gas-solids contacting having the following principle advantages: l. High thermal efficiency 2. Ability to handle a variety of feed materials with a wide range of particle sizes 3. Minimum investment and operating cost

Jan 1, 1963

By A. L. Frank, Benton

INTRODUCTION The selective sensitivity of plastic nuclear track detectors (PNTD's) to low energy 4He particles in an environment which also contains gamma and beta radiations has made these detectors prime candidates for the dosimetric measurement of the concentrations of radon and its daughter products in mine air. Their passive, integrating mode of measurement, small size, low weight and inexpensiveness are attractive characteristics for large scale personnel dosimetry. The detectors can be used in either active or passive dosimeters. In active devices, the PNTD is placed in close proximity to a sampling filter. The filter collects, from a calibrated air flow, all the daughter nuclei which are in suspension. As the daughter nuclei pass through the decay chain, through 214Po, a fraction of the 4He particles emitted are registered as latent tracks in the plastic. In passive devices, the PNTD is placed in direct contact with the ambient air containing the radio-nuclei concentrations to be determined. The active dosimeters have the advantage of excellent sensitivity, and the measured track densities yield very close approximations to accumulated Working Level (WL)** exposures. They have the disadvantage that the simplicity of the passive PNTD is lost, since a battery-driven constant flow-rate air pump is a necessity. The passive dosimeters are simple in construction and use, but they have the disadvantage that WL exposures are not directly measured and certain assumptions concerning radon and daughter equilibrium conditions must be made in determining WL exposures from the measured track densities. Also the sensitivities, in track densities per Working Level Hour (WLH) exposure, are much less than for active dosimeters. Dosimeters of both types have been investigated. Passive devices have been tested extensively both in the laboratory and in mines. Active devices have been laboratory tested. In our earlier measurements, cellulose nitrate plastic detectors were used exclusively, since this material had the highest sensitivity of the PNTD's then in use. When the properties of CR-39 plastic were discovered (Cartwright, 1978; Cassou and Benton, 1978), this material was used, where possible, to take advantage of its superior sensitivity. The results of our earlier work have previously been published (Frank and Benton, 1977). * Research sponsored by the Bureau of Mines, U.S. Department of Interior, under Contract No. JO-188003. ** A Working Level is defined as any combination of the short-lived radon daughters containing 1.3 x 105 MeV of potential 4He-particle energy per liter of ambient air. PASSIVE DOSIMETRY In the earliest testing of PNTD's for passive WL dosimetry, a single strip of cellulose nitrate plastic was used to determine the total cumulative 4He-particle activity in the air of simulated uranium mine and uranium mine environments (Rock, 1968; Rock [et al], 1969; White, 1969). The measurements yielded a close relationship between track densities and WL exposures in a controlled, static environment, but poor accuracy in the active mine tests. It was assumed that equilibrium differences contributed largely to the variations found. The response of PNTD's to airborne 4He-particle emitters, derived by Lovett (1969), demonstrated that detectors such as cellulose nitrate, which has a sensitivity cutoff at 4He-particle energies below the emission energies of radon and its daughters, are equally sensitive to the activity concentrations of radon, 218po(RaA) and 214Po(RaC'). Since radon does not contribute to WL as it is defined, and since, under normal ventilated uranium mine conditions, the radon activity constitutes about 40% to 70% of the total 4He-particle activity, the WL exposures calculated from measured track densities are very sensitive to the particular radon daughter equilibrium conditions. Also, the detector does not weight the individual daughter activities in proportion to their importance to WL. The equation for WL is WL = 0.00103C2 + 0.00507C3 + 0.00373C4 (1) where C2, C3 and C4 are the activity concentrations of RaA, RaB and RaC-C', respectively, in pCi/[L]. The detector leaves C3 unmeasured and weights C2 and C4, equally. [This problem has been approached by Domanski et al (1975, 1979), for some non-uranium mines, by measuring equilibrium conditions throughout the mines to determine a mean value for A, the inverse of the Working Level Ratio (WLR = 100 WL where C1 is the activity of radon-222 in pCi/[L].) The distribution of values allowed Domanski to determine probable errors in calculating WL exposures from track densities. However, measurements of equilibrium conditions in U.S. uranium mines (Breslin et al, 1969; Holub and Droullard, 1978) indicate that this method would not be accurate enough for uranium miner personal dosimetry.] A two-element dosimeter was designed at our laboratory to compensate for equilibrium variations. The first element is a radon detector; the second is a detector for the total 4He-particle activity in the ambient air, just as in the single element dosimeters cited above. The addition of the radon detector allows the equilibrium conditions for the individual nuclei to be determined, given certain assumptions concerning the interrelationships between the nuclei concentrations in mine air. The two detectors and the problems involved in calculating WL exposures from their measurements are discussed below.

Jan 1, 1981

By C. A. Rowland

Introduction Rod mills are horizontal, cylindrical, rotating, tumbling mills in which steel rods, that are usually about 6 in. shorter than the length of the grinding chamber, are used for grinding media. Fig. 33 shows a cutaway view of a rod mill. Rod mills were first used around 1910 because of their ability to grind in open circuit, consistently produce a uniformly sized prod¬uct, give greater continuous availability, and give lower maintenance costs. They have basically replaced roll crushers and coarse grinding ball mills in comminution flowsheets. The present 20-ft limit on rod length, based on rod manufacturing methods, and the pulp flow char¬acteristics, that influence mill capacity, have established the maximum rod mill sizes' of 15 x 21 Vs ft using 20-ft rods and drawing from 2,200 to 2,300 hp. Rod Mill Uses. The principal uses for rod mills are: preparing feed for ball or pebble mills, grinding gravel or aggregates to the size analysis required for making concrete sand, preparing coarse agitator feed for leaching operations, and for primary grinding circuits, particularly in industrial mineral applications. Wet grinding is the most frequently used grinding process for rod milling. There are a few special cases where dry rod milling is used. Preparing feed for ball or pebble mills is the most common use for rod mills. In ferrous and nonferrous ore concentrators, wet open-circuit grinding is used to prepare ball-mill feed. Figs. 34 thru 37 show the four basic grinding circuits used in these concentrators. In rod mill-ball mill grinding circuits, where the rod-mill discharge contains 25% or more of the grinding circuit product-size material, the rod-mill discharge can be fed to the ball- or pebble-mill classifier as shown in Fig. 34. This is the most frequently used rod mill-ball mill circuit in the nonferrous ore concentrators. In a few concentrators such as Anaconda's Weed concentrator,55 the rod mill discharges to one classification stage which makes the same or a slightly coarser particle-size cut as the classifiers used to close the ball- or pebble¬mill circuits, as shown in Fig. 35. In concentrators where rod mill-ball mill circuits are used to grind low grade magnetic iron ores such as Reserve Mining Co., Silver Bay, Minn.; Erie Mining Co., Hoyt Lakes, Minn.; Eveleth Taconite Co., Forbes, Minn.; US Steel, Mt. Iron, Minn. and Atlantic City, Wyo.; Inland Steel-Jackson County Iron Co., Black River Falls, Wis.; and The Cleveland-Cliffs Iron Co., Adams mine, Kirkland Lake, Ont., the rod mills discharge to rougher magnetic separators (cobbers), the concentrates from which are fed to a ball milling stage as shown in Fig. 36. The same basic circuit is also used with gravity concentra¬tion methods such as spirals (Hanna Mining Co., Groveland, Mich.), tables (St. Joe Minerals, Bonne Terre, Mo.), and jigs. When the rod-mill discharge contains less than 25% of the grind¬ing circuit product size, this indicates an ore that does not readily produce the fines needed to help carry the coarse feed into the ball charge. When this occurs, the fines in the rod-mill discharge are needed in the ball mill or pebble mill so the rod-mill discharge flows direct to the second-stage mills as shown in Fig. 37. Rod mills are used to make feed for open-circuit ball mills such as those used in wet grinding cement raw material (American Cement, Brennan Ave¬nue plant, Detroit, Mich., and Port Huron, Mich., plant, and at the South Dakota State Cement plant, Rapid City, S. Dak.). Grinding gravel or aggregates to the size analysis required for making concrete sand is used in areas where natural sand of the proper particle size gradation required to make concrete is not availa¬ble. Three-quarter inch crushed aggregate is ground to 4 mesh using center peripheral-discharge rod mills (Fig. 38) operating in open circuit. US Corps of Engineers specifications state that the sand product be 93-100% passing 4 mesh and contain no more than 3-7% passing 200 mesh. It may be necessary to classify the rod-mill discharge to remove any excess -200 mesh sand produced in the rod mill. Particu¬larly when processing aggregate with high abrasion indices, center peripheral-discharge rod mills are used instead of hammer mills, fine bowl crushers, and crushing rolls for the production of specification sand. If the -4 mesh size fraction of the rod-mill feed is removed

Jan 1, 1985

By Jr. Schnakenberg

The automation (robotization) of coal mining activities at the face offers improvements in worker safety and productivity. The evolutionary introduction of autonomous, intelligent robotic machines to perform the most hazardous tasks may become a reality within the next 10 years. The U.S. Bureau of Mines Robotics and Automation research program is aggressively pursuing the development of the enabling technology necessary to achieve this goal. This program consists of both core and applications research, each focused on the fundamental issues of robotic technology. In the short term, the research is directed specifically to the robotization of present-day underground equipment and is being performed in a manner that can make incremental improvements in safety and productivity. The long-term goal is the development of intelligent autonomous mining systems.

Jan 1, 1990

By James W. Mitchell

On December 2, 1942, a scientific team lead by Nobel Prize winner Enrico Fermi first initiated and controlled a self-sustaining nuclear chain reaction. This historic event occurring beneath the stands of the University of Chicago football stadium instantly created an entirely new and tremendously broad area of technology. Indeed, the event probably changed the course of world history and considering the curret energy shortage, it probably came none too soon. Following many technological breakthroughs in the ensuing years, this event led to the first full scale nuclear fueled electric generating plant. In December, 1957, the Shippingport Nuclear Power Plant became operational and the United States had entered the era of the nuclear fueled electric generating station. Today, only fifteen years later, there are some thirty-five operating nuclear power plants in the United States with another 56 under construction and 116 on order. Still, we are only scratching the surface of this tremendous energy source. In 1970, less than one-percent of the total electric generating capacity in the United States was nuclear fueled. By 1985, it is projected that 45% of our generating capacity will result from nuclear power plants. These projections are based upoa statistics of six months to a year ago and considering the current energy shortage and recent attempts by the United States Atomic Energy Commission (USAEC) to speed the licensing process and encourage standardized plants, the contribution of nuclear power to our total generating capacity may be even greater. In summary, it is obvious that nuclear power is now, and will continue, playing an important role in our future. Those factions of government, industry and the professional community charged with fully developing this tremendous energy source must deal with it rationally, logically and expediently. The various environmental considerations in nuclear plant siting play an important role in the overall plan.

Jan 1, 1974

By C. B. Manula

The application of computers to materials handling problems has recently been investigated by various mining groups. This approach has been found, especially useful where a large amount of alternatives must be investigated prior to arriving at a final decision. These alternatives may be expressed in terms of man hours, units and types of equipment such as trucks or conveyors, or the allocation and operation of proposed or existing haulage facilities. The decision problem becomes especially evident when we consider the mechanical revolution which has flooded the mining industry in recent years. The industry has become highly competitive, with the need to keep low profit materials away from high cost production faces ever increasing. The capital investment required for the highly sophisticated equipment that is necessary to perform this function is generally great, and management is faced with decisions which must all too often be made without sufficient data.

Jan 1, 1967