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By Fathi Habashi

IT APPEARS that the phenomenon of ion exchange by which saline water was converted to sweet was known to Moses and Aristotle. However, the credit for the recognition of this process is generally attributed to Thompson (1850) and Way (1850), who reported that when a soil was treated with either ammonium sulfate or ammonium carbonate solution, most of the ammonia was adsorbed and calcium was released. It was later proved by Eichorn (1858) that the adsorption of ions from ground waters by clay constituents was a reversible process. The first attempts to utilize ion exchange phenomena was in the field of water softening around 1906, using natural and synthetic silicates. In 1935 Adams and Holmes in England observed that crushed phonograph records (phenol-formaldehyde and amine-formaldehyde resins) were capable of exchanging ions.

Jan 1, 1970

By J. Herbst, H. W. Kropholler, L. A. Cramer, E. T. Woodburn, J. C. A. Greene, G. Poling

A generalized mathematical structure is proposed whereby internal species mass flows within a flotation network are defined uniquely by a matrix of enhancement factors. An element of the enhancement factor matrix is defined as the ratio of the mass flow of that species leaving a given cell in the concentrate to the species mass flow leaving the same cell in the tailings. To predict the enhancement factors, knowledge of flotation kinetics effects is required. Recently experimental data has become available relating to the performance of industrial flotation circuits which indicate that the discrete or discrete-distributed kinetic schemes are capable of reasonably effective simulations. These simulations show the importance of including froth effects. The prediction of performance of networks from small-scale batch tests on flotation streams shows that the model for the froth phase used in the simulations does not scale-up well and that aeration effects are also difficult to predict. The network analysis should be useful in differential flotation of complex ores and it is disappointing in this context that little information on the kinetics of activation and depression is available.

Jan 1, 1976

By B. P. Mohanty, D. A. Shores

During the induration of fluxed taconite pellets, alkali salts deposit on the grate support bars, causing severe corrosive degradation of these alloys. To determine the source of these deposits and to understand the mechanism by which the salts are conveyed to the grate bars, a study of the reactions between fluxed pellets and combustion gas was carried out. The study focused on the thermodynamics and kinetics of several processes associated with induration; namely, oxidation of magnetite, calcination of flux, and the formation and gaseous transport of various alkali salt species. Both theoretical and experimental techniques were used. It was concluded that the principal source of alkali salt deposits is alkali chlorides, which are present as contaminants in the flux and/or residue from contaminated washwater. The pathway from pellet to grate bar involves the following steps: evaporation of chloride salts within the pellet; diffusion of salt vapor out of the pellet, aided by the outflow of CO2 from calcination of the flux; convective transport by the combustion gas with concurrent (partial) conversion to alkali sulfates by reaction with residual SOX in the combustion gas; and condensation of salts on the grate bars.

Jan 1, 1998

By Victor F. Hollister

Porphyry copper deposits can be categorized into three models for purposes of prospect evaluation: Breccia-pipe, modified Lowell and Guilbert, and diorite models. The modified Lowell and Guilbert model is normally associated with a quartz-bearing intrusive and a potassic, phyllic, argillic, and propylitic alteration sequence. Variations can occur in the alteration zones of this model that range from orthoclase-rich (Kalamazoo, Silver Bell, and Mineral Park) to ortho- clase-deficient (Petaquilla and Bougainville) potassic zones. The unifying features of the model are the presence of a phyllic zone and a quartz-bearing intrusion. The breccia-pipe model (Toquepala) is characterized by structure and alteration related to or controlled by breccia. Where tourmaline occurs in the breccia, the identity of the model is usually clear. However, if tourmaline is not commonly developed in the breccia (La Caridad), the deposit can be misidentified as to model. Porphyry copper deposits associated with quartz-deficient intrusives, whether these are calc-alkalic diorites or alkalic plutons, are characterized by alteration suites distinct from those of the modified Lowell and Guilbert model. These have been generalized as diorite model porphyry deposits. Because alteration and mineralogical development in diorite model deposits is distinct from that of the modified Lowell and Guilbert, ore guides and exploration tactics differ for the two models. The reprint that follows describing the three prospecting models summarizes their features. It is to be emphasized that these are models used in exploration for specific deposit types and are not genetic, tectonic, or geographic models. Porphyry copper deposits can be metamorphosed. Gibralter is an example of a Lowell and Guilbert model deposit that has undergone regional metamorphism.

Jan 1, 1991

By Nicholas T. Camicia

A career in the coal mining industry today offers students one of the most interesting and challenging opportunities available in the industrialized world. As reserves of other fossil fuels dwindle in face of the world's demand for energy, it has become apparent that coal, once the king of energy sources, must be relied upon again as the major fuel for powering industrial growth in developed and developing nations. Centuries of coal supplies lie beneath the earth's surface, assuring the world of a steady, plentiful supply of energy until science and technology can produce a way to harness and efficiently use renewable sources, such as solar. The need to increase our use of coal during the last two decades of the 20th century is reason enough to believe that the future growth of the coal industry is assured. A major impediment to that growth might be backward national public policies that could restrict the full utilization of our coal reserves. These policies could result from overregulation and a failure of the public to recognize that coal use, with proper techno- logical safeguards, is compatible with our society's environmental-quality objectives. Communication of this problem and its solution is a major undertaking of the coal industry in the 1980s. At the end of the 1970s, the American coal industry was producing approximately 635 Mt/a (700 million stpy) of coal. To meet the nation's projected energy needs by 1985, the annual tonnage must be doubled. A similar scenario is predicted for the rest of the world. Such growth in the modern international business world will require huge additional amounts of capital, equipment, and people who know how to wisely raise and apply the capital ; use the equipment productively; and deal with the many community, public, and governmental problems such expansion will create. Whether a student's interest is in actual mining operations, business administration, engineering, finance, law, industrial relations, marketing and sales, or public affairs, a career opportunity is available in the industry.

Jan 1, 1981

By Kenneth S. Graham, S. C. Gambrell

A short term, simple roof bolt load cell which uses a birefringent (photoelastic) coating as its sensing element has been developed. The load cell is installed between the bearing plate and the nut/washer and measures the initial force after installation by the bolting machine. The load cell can be removed from the bolt and used again to measure initial force in another bolt if desired. Because temperature and humidity changes in the mine cause creep/relaxation of the coating and/or adhesive, the load cell is useful for accurately measuring force for a period of only two weeks after installation. Force in the bolt is determined by referring to a calibration curve for the load cell.

Jan 1, 1992

By Herbert S. Richey

Two hundred years ago next April, our forebears embarked upon the difficult path to national independence. They succeeded, and shook off the yoke of foreign domination. In the ensuing two centuries, the country was mobilized several times to protect that political and economic independence from foreign domination. These efforts were also successful. Thus, as we stand here on the threshold of our third century of political independence, we can thank previous generations and congratulate ourselves for establishing and maintaining the world's oldest republic. Now -- once again -- the United States faces the challenge of foreign intervention into our economy. This time the battleground is resource avail- ability. America has been blessed with enormous resources. Whether we speak of minerals or timber or water or "amber waves of grain," this nation has benefitted from a resource base that is the envy of the world. This asset, coupled with a political system that permitted us to develop it, has been the physical backbone of our independence. Without the economic independence that this resource base has given us, the political independence we fought for would have been tenuous, at best.

Jan 1, 1975

A new fluid bed lime calcining plant is converting high quality limestone into quicklime at the Cape Lime facility in Vredendal, South Africa. The plant was supplied by Metso Minerals. Cape Lime, established in 1946, operates two limestone and dolomite mines in South Africa. The high quality Vredendal limestone deposits are suitable for the production of lime for water treatment and for manufacturing precipitated calcium carbonate.

Jan 1, 2003

By Leo Misagi

THE ROLE OF MANAGEMENT IN PLANT SAFETY Safe Production In plant management, safe production is an ideal. It becomes reality when: 1. Plant employees work in healthful and safe conditions. 2. Plant safety is in harmony with productivity. 3. Worker absenteeism and turnover are low-the work force is stable. Plant management must apply its talents, skills, and resources to build and maintain the foundations of safe production on a system of policies, procedures, and attitudes. It must do so by marshaling all managerial functions - staffing, direction, control, innovation, and representation-toward that goal. Ideally, a plant safety program is proactive. Management should plan and implement safety activities that are aimed at prevention. Past accidents-accomplished facts-should not be the sole guide of future actions. In other words, positive preventive measures, not the fewness of accidents are the criteria for safety production. An ideal safety program is one which is cost effective. Management should view plant safety as part of a broader program-loss control. Loss control includes prevention of fires and other accidents, unhealthful conditions, and occurrences that cause bodily injury, illness, property loss, or damage. Management evaluates the employees' productivity and safety. An effective training program aimed at loss control is the hallmark of safe production. Ideally, both labor and management should be well versed in safety. They believe in the premise that work-related injury and illness, as well as property loss and damage from fire and other accidents, are manageable and preventable. Such belief prompts them to learn more about the work process and potential hazards associated with each job. They also learn how to expect and prevent fues and other accidents, and respond to emergencies at the plant. Plant management determines which individuals or groups of employees are accountable for the following functions:

Jan 1, 1991

By G. W. Kenzy

Recently, in the United States, questions of possible deleterious synergistic health effects of the gaseous and particulate components in the diesel exhaust and mineral and coal dust have been the impetus for extensive research by several agencies. At the present time, diesel engines are tested and approved for use in gassy and non-gassy underground metal and non-metal mines under Parts 31, 32, and 36 of Title30 of the Code of Federal Regulations. Diesel-powered equipment for use in underground coal mines, though not explicitly addressed in the law, is administered under Parts 32 and 36 of Title 30, with Part 36 being applied in the case of equipment working inby the last open crosscut or in the return airways. Operation of diesel equipment in underground mines has the potential for serious health and safety hazards from the gases, vapors, and particulates in the exhaust. Therefore, various countries have rules and regulations for the safe deployment of diesel equipment. The applicable laws and regulations from several countries who have long experience with diesel-powered equipment in their mines are reviewed. Four major areas have been addressed: (1) testing and approval procedures of diesel engines, (2) ambient mine air quality specifications, (3) frequency of sampling and location of samples, and (4) air quality specifications in splits where diesel-powered equipment are operated. The review indicates that most regulations generally consider four possible hazards: (1) toxic components in the engine exhaust, (2) ignition of flammable atmospheres by the engine or electrical equipment, (3) fire hazards presented by the engine fuel oil and by combustible material that might come in contact with the equipment, and (4) mechanical hazards. There is a remarkable similarity in the laws with regard to engine design, testing and approval procedures. However, the aspects with regard to mine air quality and quantity are quite variable-- from a general statement to very specific standards for many different diesel exhaust constituents. However, the laws with regard to synergistic effects of diesel exhaust components and other mine air contaminants are an exception.

Jan 1, 1980

By S. G. Hardcastle, Akbar Sheikh

In Canadian underground uranium mines, bacterial leaching is being increasingly applied to low-grade ore reserves. At Denison Mines Limited uranium operations, old stopes are used as leaching vessels; these contain a leaching muck pile brought down by drilling and blasting from the back which contained a low-grade reef. The bacteria used require atmospheric oxygen to oxidize the pyritic ore. A study was initiated to evaluate the ventilation, including oxygen supply, specifically, of flood leaching stopes during their rest period. The method of ventilation investigated was a single ended compressed air system which feeds airlines laid under the muckpile and carried through the inlet pressure bulkhead. The air delivery system was tested for post- blast integrity with a sulphur hexafluoride, SF6, tracer gas technique. This was injected into the intake compressed air line and collected at the stope's borehole exhaust in grab-sampling bags. The samples were analyzed with a laboratory gas chromatograph and results provided information on the stope's airflow, average residence time, overall clearance time, volume of the airpath and the airflow distribution. The borehole exhaust was monitored by anemometer and psychrometer and indicated that the psychrometric conditions in the stope were independent of the area's ambient climate. Evaluation of the exhaust's standard gaseous composition showed the oxygen consumption of the bacteria to be independent of the investigated flow range. Field derived results are compared with computer models, theoretical predictions and laboratory investigations.

Jan 1, 1987

By R. Todd Swinderman

Variations in designs between belt cleaner systems are so wide that it is impractical to establish a dimensional stan- dard. The number of variables that affect the efficiency of belt cleaners is too great to assume a required number or style of cleaners for broad classifications of bulk solids or typical applications. The amount of carryback remaining on the belt is more dependent upon the characteristics of the bulk solid and the physical parameters of the conveyor system than it is on tonnage of material conveyed. Therefore, a performance-based standard is proposed. Three levels of cleaning performance are proposed: • Level I cleaning is general specified when concerns about carryback are not critical. Cleaning systems normally associated with achieving a Level I performance are single or double cleaner systems with one-piece blades undergoing poor to average maintenance. Frequent cleaning of the carryback that falls from the return run will likely be required. • Level II cleaning is generally specified when carry- back is of concern but does not create a safety or environmental problem. Cleaning systems normally associated with Level I1 performance are multiple cleaner systems with segmented blades undergoing the manufacturer's specified maintenance. Regular but infrequent cleaning of the carryback that falls from the return run will likely be required. • Level III cleaning is generally specified when con- cerns about carryback are critical. Concerns range from safety to environmental to product contamination. Cleaning systems normally associated with achieving a Level 111 performance are multiple cleaner systems in conjunction with at least one low- volume water spray. Scheduled inspection and the manufacturer's specified maintenance would have to be performed to maintain a high level of cleaning performance. Difficult-to-clean bulk materials may require the use of a washbox system with multiple cleaners using a combination of low-volume eater sprays to lubricate the cleaners and high-volume sprays to keep the washbox and discharge piping freely flowing. Further addition of a water and sludge recycling system reduces the amount of water that ends up in the product to a negligible amount. Very infrequent cleaning of the carryback that falls from the return run will be required. PURPOSE The purpose of this proposal is to propose a standard method for specifying belt cleaner systems based on user expectations and equipment performance over time. DEFINITION In bulk solids handling by conveyor belt, carryback is the material that adheres to the belt after the belt discharges its cargo. PROPOSED STANDARD Required Basic Good Practices There are a number of basic design and operating principles that are good practice for the selection, installation, and maintenance of belt cleaning systems on conveyors in order to achieve "standard belt cleaning performance over time. 1. The Belt Cleaning System shall be designed to meet the performance requirements based on the worst operating conditions and worst bulk solids proper- ties that are expected. 2. Each conveyor discharge point shall be designed to readily accept the manufacturer's recommended minimum number of belt cleaners. In addition, the discharge chute shall be designed to accept, with minor modifications, at least one additional cleaner if it is required.

Jan 1, 2004

By Yoginder P. Chugh

The Department of Energy is presently sponsoring the development of automated miner-bolter machines in an effort to increase production and productivity in the continuous room-and-pillar mining sections. This study is concerned with the production potential of these machines in three different mine layouts. The Underground Material Handling Simulation (UGMHS) computer model was utilized in the study. The effect of variables such as bolt installation delay, shuttle car capacity, and equipment availability on production are analyzed.

Jan 1, 1979

By K. C. Carriere

INTRODUCTION The purpose of this paper is to introduce the reader to basic control strategies for solid/liquid separation in mineral processing and to indicate some of the implementation difficulties to be encountered, without becoming overly involved in details of process, equipment or software. It is assumed that the reader has some familiarity with control systems and with dewatering processes, since exploration of these topics would require considerably more length. The paper is organized into three parts: first a general discussion on the need for control of dewatering processes and of the general criteria involved, next a more detailed elaboration on control strategies for the various unit operations, and finally a case study showing a specific approach towards such a project. Motivation & Objectives The justification for implementing any control system in an industrial plant is to improve operations and thereby to increase profitability. Without this motivation, the system will likely be perceived as unnecessary and will decline into disuse, an expensive and troublesome monument to someone's ill-conceived ideas. However, when a control strategy is correctly conceived, implemented and integrated into operations, it can provide significant advantages in operating ease and efficiency, and a handsome return on investment. In general terms, the objectives in establishing a control system are: • stabilization of process disturbances maintenance of product quality • maximization of throughput • dearer definition of process • protection of personnel and equipment A successful control strategy must address at least some of the above criteria. However, the most important requirement is a commitment on the part of plant personnel and management to start up, operate and maintain the system, and to upgrade it to reflect current process status and operational philosophy. Process Applications In this paper, control strategies will be explored for the most common methods of dewatering of mineral pulps. These unit operations include: drying, centrifuging, filtering and sedimentation. While the first three are important, they do not tend to be as complex as sedimentation, and thus will not be as exhaustively treated. Sedimentation is very widely applied, not

Jan 1, 1986

By R. M. Guymon, D. D. Lauriski

Safety management can best be described as how each company deals with the control of hazards (human or mechanical) to reduce costly accidents and employee injury caused by accidents. Properly used, effective safety management can mean the difference between being a highly productive, cost-efficient operation or one that "walks the fence," that is less productive with higher product costs. At Utah Power & Light Co's mining division, effective safety management has been used as tool to achieve this difference and remains as the number one priority to maintaining that difference.

Jan 1, 1990

By Felicia F. Peng

Flotation process is particle hydrophobic surface-based separation technique. To improve the essential flotation steps of collision and attachment, and reduce detachment probabilities between air bubbles and hydrophobic particles, a selectively designed cavitaion venture-tube can be used to generate very high numbers of pico-nano bubbles to flotation column. Fully embraced by those high numbers of tiny bubbles, hydrophobic particles are readily attracting those tiny bubbles to their surfaces. The results of column flotation of Pittsburgh No.8 seam coal are obtained in a 50 cm ID and 162cm height flotation column equipped with static-mixer and cavitation-venture tube, using kerosene as collector and MIBC as frother. Design of experiment procedure combined with statistical two-stepwise analysis method are applied and attempted to made the optimizing the grade and recovery. The effect of independent variables on response has been explained. Combustible material recovery of 85-90% at clean coal product of 10-11 % ash are obtained from feed of 29.6% ash, with reduced amount of frother and collector than that used in conventional column flotation. The column flotation process utilizing the pico-nanobubbles can also be extended to the lower limit and upper limit of particle size ranges for better recovery minus 75 µm and 300-600 µm, respectively.

Jan 1, 2013

By W. H. McDonald, D. D. Carr

The use of stone in building construction predates written history. From the time that stone was first used, builders have constructed stone buildings predominately from local or regional materials. However, since World War II, the stone business has become increasingly global. For example, French limestone is now sold to builders in the United States, and American granite is shipped to Japan. The internationalization of architectural and construction firms has encouraged this trend. Differences among nations in trade practices, environmental demands and the level of knowledge of dimension-stone characteristics make international trading in stone a risky and potentially disastrous business for unwary participants.

Jan 1, 1997

By Patzen Wu

The Hai-Shan No. 1 Coal Mine, located in northern Taiwan, is one of the typical coal mines on the island which, limited by natural condition, are mostly small in scale. With the advancing longwall method, the mine is now winning a seam, 80 cm thick, at a 32° dip, with a working depth of 824 m below surface. The annual output is about 50,000 mt of clean coal. At the working gallery, the virgin rock temperature may go up to 46°C, difficult to be brought dam to n acceptable level: because .of the tropical climate with high intake temperature and high humidity. Besides, at this depth, the intake air that goes down the long inclined shaft generates considerable heat due to autocompression. The mine is ventilated by a set of axial-flow fan with 38 m3/S of intake air at 2.2 KPA WG. With this volume of air, the temperature at the working-face is usually above 30°C WB. Appreciable lowering of the temperature is not expected even with an increased volume of ventilated air. For this reason, decision has. been made to try the installation of a pilot underground refrigeration unit near. the lowest gate road to cool the intake. air. from 32°C WB to 28°C WB which seems acceptable to on-the-spot workers exerting heavy physical labor. The experimental unit is designed for carrying away a total heat load of 90 Kw. The capacity of the unit is 200 Kw. The unit consists of a compressor, an evaporator, a condensor and a motor. The heat rejection is done in a cooling tower. Chilled water is circulated from the evaporator to the cooler by insulated pipes. The cooler consists of 90 Kw-coils with two fans and forces air by flexible ducting onto the working face. This paper examines mainly the effect of this additional reduction of working temperature, on working efficiency of the workers. Another aspect of this experiment is to evaluate the overall economy of underground refrigeration in small-sized coal mines under tropical condition. The success of such an experiment may lead to wider application of refrigeration to render many of the deeper mines economically workable.

Jan 1, 1980

By Thomas E. Shufflebarger

Glass sand is a virtually pure, fine- to medium-grained, quartz sand. It is produced in 25 states from a variety of chemically different source rocks. Deriving their raw material largely from either friable sandstones or loosely consolidated sands, 59 operations produced 14.9 million tons of melting sand in 1976. About one-third of this tonnage was obtained from the Oriskany and St. Peter Sandstones. Glass-sand prospects are discussed in this paper with regard to chemistry, environment, transportation, and costs. Demand for a quality product will range from 36 million to 46 million short tons in 1995.

Jan 1, 1978

By L. A. Obasi, C. Obasi

Investigations were carried out to determine the effects of changing metamorphic conditions on the formation of magnetite from the Itakpe iron ore deposit. Various magnetite grain sizes from ferruginous quartzites from different zones were determined and analyzed statistically. The results reflect the reaction of mineral individuals. In particular, the granulometry of magnetite changed with changes in the mineral formation conditions in the deposit and correlate with the mineralo-geochemical zones. This is interpreted as part of a readjustment of the mineral to the prevailing conditions. Because granulometry is a prebeneficiation parameter, this work will be, no doubt, of importance to the exploitation and beneficiation of the quartzites and rich ores.

Jan 1, 2000