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By Richard Newcomb

Since the report of the 1972 Rapid Excavation Conference in the city of Chicago, speculation has continued concerning the estimates of tunneling demand. Little has been published that would persuade me to modify substantially the rather tentative estimates that originated with the National Academy of Sciences-National Academy of Engineering (NAS-NAE) study of 1968 which were recomputed by the United States in the survey of the Organization for Economic Cooperation and Development (OECD) in 1970. The OECD estimates, of course, hedged the really difficult question of forecasting civil construction tunneling demands. In the United States contribution, this was done by predicting both an upper and lower bound for important categories of demand. A discounting procedure was then applied to each of the major sectors of expenditures, permitting a forecast that reflected the current subjective assessment of how extensively and how likely cities were to adopt plans that required tunneling. This was done for water, utilities, transportation and other novel underground facilities. The purpose of this paper is a modest one. In it I wish to describe the efforts made since 1972 to generate more thoughtful and more robust estimates of urban sector demands, and to apply what has been learned to the most difficult category of predictions: those for urban mass transit systems. The estimates of the Underground Construction Research Council funded by the National Science Foundation have been described at an earlier panel of this Conference. The principal effort I am familiar with is that of

Jan 1, 1974

By Liguang Wang, Roe-Hoan Yoon

The thin film balance (TFB) technique was used to measure the equilibrium film thicknesses (H3 between two air bubbles in sodium dodecyl sulfate (SDS) and electrolyte (NaCl) solutions. The results were used to determine the magnitudes of the hydrophobic forces (K232) using the extended DLVO theory. The Km values determined from He measurement allowed us to predict disjoining pressure isotherms, which were found to be in excellent agreement with those obtained experimentally using a bike-wheel film holder. The rate of film thinning was measured at low SDS concentrations with varying amounts of electrolyte (NaCl) added. In general film thinning was controlled by the capillary pressure during the initial stages, while it was controlled by the surfaces forces during the later stages. At low NaCl concentrations, it was possible to predict the rate of film thinning using the Reynolds equation, provided that the driving force was corrected for the contributions from the hydrophobic force, which in turn were determined from the KZ32 values obtained from the He values measured experimentally. At high NaCl concentrations, where it was difficult to measure the equilibrium film thicknesses, the contributions from the hydrophobic forces were determined by fitting the film thinning data to the Reynolds equation. The K232 values obtained using both the equilibrium film thickness and the film thinning measurements showed that hydrophobic force deceased with increasing surfactant and salt concentrations. It was found that the hydrophobic force in foam films was very sensitive to the added electrolyte concentration.

Jan 1, 2005

By A. T. Yu

Two key components make up the core of a rapid excavation operation. They are: the breaking up of the rock and its removal. Owing to the complexity inherent in mechanical rock-breaking and the relative infancy of the art, for a number of years the first of these two components has received virtually undivided attention from the industry. Only recently has some concern been expressed about the technology and the economics of the much ignored second component: muck removal. As the continuous boring machine's percentage downtime continues to trend lower in the future, the need for adequate and more effective materials handling systems in rapid excavation will become increasingly more acute. (1) Recognition of the need for a broader and more far-sighted approach to our problem has been eloquently underscored in the conclusions of the Committee on Rapid Excavation sponsored by the National Research Council: "Ultimate attainment of the desired cost and speed improvements is significantly dependent on recognition of the excavation process as a system whose subsystems are critically inter-related. Substantial amounts of full-scale field testing of integrated driving, muck removal, and support subsystems are required." (2)

Jan 1, 1997

By Marcel Haffen, Jean Janin

The purpose of grouting is to modify the permeability and strength characteristics of the subsoil in such a way that the planned structure can be efficiently constructed at a given location. This technique, which originally underwent considerable development in the field of dams construction is constantly evolving and it becomes more and more important in urban zones of intensive underground development for projects such as transport tunnels, stations, car parks, ect. Grouting becomes more and more indispensable whatever the natural characteristics of that subsoil ; such is the case particularly when the planned work runs through cohesionless granular soils, usually water-bearing such as alluvium, sands, disturbed ground, fill material, etc. The selection of the grouting method and the extent of treatment required at depends on two fundamental factors. 1º) nature and behaviour of subsoil to be treated. There is no need to stress the necessary of a good knowledge of geotechnical, hydrological and chemical characteristics of the ground to be treated. At the present time the specialists in these fields have available numerous methods of analysis, either laboratory or field tests, which enable to evolve a suitable treatment.

Jan 1, 1997

By T. S. Golosinski

Timely and efficient conversion from traditional to sustainable development of mineral resources requires that managers, engineers and other mineral industry professionals become familiar with the related techniques and methods. To fill this need the online Master of Engineering program has been developed at University of Missouri-Rolla. Designed primarily for mature students with an engineering or science background this program allows for specialization in several areas of sustainable development of earth resources. To accommodate mineral industry professionals working in remote locations all courses constituting the program can be taken online, without the need to attend the classes in person. The paper describes the program and discusses the experience gained during the first two years of program offering.

Jan 1, 2003

By William M. Clark

In 1988, the Chemical Manufacturers Association (CMA) launched Responsible Care®, a program of guiding principles created to address the publics' concern about the manufacture and use of chemicals. The Product Stewardship Management Practice code is a key component of the program. Along with the other five comple­mentary codes - Community Awareness and Emergency Response (CAER), Pollution Prevention, Employee Health and Safety, Process Safety, and Distribution - it has been initiated to protect the health and safety of member companies employees, neighbors, customers, the public and the environment. Possibly no other Management Code requires greater collec­tive effort or comprehensive commitment to implement than Product Stewardship. With its mandated cradle-to-grave control, every employee is required to consider all of the potential cir­cumstances involving product and processes, from raw material supply to customers final use or consumption of product. Degussa Corporation, a long time CMA member, fully endors­es the Responsible Care initiative and is most active in imple­menting the various codes. In fact, the guiding principles of the program are an integral part of the company's business strategy. Degussa recognizes that its long-term success and the health of each of its products, the company and the chemical industry itself, is contingent on the successful implementation of the program. Furthermore, the company believes its role in society and the economy can only be justified and sustained if it improves the overall quality of peoples' lives. Consequently, it is a dictum that Degussa products must provide a net benefit over their entire life cycle - from inception to final disposal - both in terms of their utility and their impact on health, safety and the environment.

Jan 1, 1998

By M. J. Hrebar

Surface coal mine design has traditionally relied on graphic and analytic approaches for pit layout and equipment selection. A number of interactive graphic microcomputer programs have been written which aid in the design process in the academic arena and should also have industrial applications. The programs described include a dragline cut diagram and production index calculation program, a downslope load scraper cut diagram and volume program and an overburden volume and coal tonnage sequencing program.

Jan 1, 1985

By Nelson R. Shaffer

Implementation of the Clean Air Act Amendments of 1990 is negatively affecting production of coal used for generating electric power in Indiana and elsewhere in the Midwest. Required reduction of sulfur compounds from gas streams, or flue gas desulfurization (FGD), as mandated by these laws has encouraged installation of wet limestone scrubbers at many generating plants. Increasingly stringent requirements that will begin in 2000 are expected to necessitate even more extensive use of such scrubbers. Indiana has large deposits of limestone-the major consumable alkaline raw material for scrubbers-that can meet an expected demand of several million tons per year. Limestones are not, however, all the same. Different limestone units behave quite differently when used as scrubbing agents under differing conditions in actual practice. Decisions about FGD scrubber details would be more meaningful if made with thorough knowledge of which rock units contain the most efficient FGD limestones and which sites of suitable stone are located nearest to power plants. Even though abundant carbonate rocks occur in Indiana, their suitability in scrubbing systems has received little attention, and few attempts have been made to match details of stone resources to the needs of various utility scrubbing systems. Optimization of the fit between geologic characteristics of the existing limestones and prospective scrubber systems should allow for greatly improved planning and operation of FGD systems with attendant lower overall costs. Electric utilities have developed computer models to predict FGD system operations (i.e., the FGD-PRISM model of the Electric Power Research Institute). These models require geologic data such as reactivity that are commonly unavailable. We generated data needed for the model during a cooperative effort among the Indiana Department of Commerce, the Indiana Geological Survey (IGS), The Indianapolis Power & Light Company (IP&L), and the Indiana Mineral Aggregates Association. Our goal was to provide missing geologic details of Indiana scrubber-stone raw materials and apply them to the FGD-PRISM model to provide general guidance to determine which geologic units can provide stone for most efficient sulfur removal. Results of the model for selected limestones and parameters specific to one IP&L generating plant were calculated. Geologic data generated may be applied to other generating operations, and our examples should help other utilities optimize their FGD strategies. Several hundred samples from more than 30 active quarries were collected and their physical properties determined. Grindability values ranged from 7.2 to 21.7 for 50 selected samples. Acid-insoluble residues of less than 1% to 13% were found. Dissolution rates as an index of reactivity varied over two orders of magnitude for the selected set of samples. These data plus chemical analyses and Ca/Mg ratios were entered into a generic scrubber model to determine rates of stone use and scrubber efficiency for various stone. Removal of SO2 was projected by this model to range from 89% to 98% with stone utilization rates from 91% to 93%. Excellent scrubber stone sources were found in Mississippian rocks in central and southern Indiana. Rocks of the Ste. Genevieve and Salem Limestones were especially efficient. Even small amounts of dolomite, clay minerals, and quartz diminished a stone's usefulness for FGD scrubbing.

Jan 1, 1999

By Ching-Yi Tsai

The effect of various constituents on the pyrolysis and combustion of a pulverized coal in an entrained-flow reactor has been inves¬tigated. Predicted time-temperature histories of the coal' particles and experimental weight loss data indicate a strong coupling of heat and mass transfer to the pyrolysis and combustion rates. A higher combustion rate following ignition was observed as particle size was increased to 112 µm. This is related to a higher particle temperature after ignition for the larger particles. Although the heating rate prior to ignition decreases with increasing particle size, higher slip velocities and surrounding gas temperatures for the larger particles promote early ignition. The presence of liptinite in the coal increases the weight loss rate before and immediately after ignition. Similar behavior was observed for pyrolysis. Fractions of a HVA bituminous coal which were rich in mineral matter or semi-fusinite were found to have a higher heterogeneous char combustion rate than vitrinite rich samples.

Jan 1, 1984

By J. A. Herbst, Z. Rogovin

In order to develop more accurate procedures for scale-up and design of semi-autogenous grinding mills through detailed mathematical models, a better understanding of the charge motion and rocklball segregation is needed. To achieve this a 0.61 m (2.0 ft) diam by 0.305m (1 .0ft) length plexiglas mill was constructed as a scale model of a commercial SAG mill. Rock motion in the rotating mill was simulated using various sizes of ceramic balls. Quantitative measurements of dynamic angle of repose, water and slurry motion, holdup and size segregation of the charge were taken. In addition, a video presentation (available to the public) was prepared to elucidate charge and water motion at various mill speeds, charge volumes, rocksize distribution, and flow rates.

Jan 1, 1990

By Charles A. Hickey

The dining industry game tome Spruce Pine area a few years after tine Civil War. Two Yankees came down from Massachusetts to mine sheet mica to sell to the stove manufacturers for windows in heating stoves. At this time the method of mining was very crude; it was done only with pick and shovel. They were mining mica from the soft veins. Later they progressed to hand grilling and blasting. Hand drilling was quite an art in the area. One man would hold and turn the steel while one or two other men would drive the steel with hammers. In shaft raining, the muck and water was removed by hand winches called windlasses. About 1920 air compressors and jack hammers came into use. These were perhaps tide greatest improvement that has ever come to the area's mining industry. Later carne gasoline hoists, air drive water pumps, and all electrical equipment. Mica mining has, for the past few years, been very modern and efficient.

Jan 1, 1962

By Patzen Wu, Chao-Ming Tsai, Shaw-Chii Wu, Yuan Lin

INTRODUCTION The development of nuclear industry in Taiwan requires an increasing supply of uranium. Uranium recovery from phosphate ores, becomes an important item of the R & D programs. Many countries have already started such a program. USA has set up an industrial-scale production plant; South Africa, Israel, Morocco and other countries have also engaged in the development of extraction technology of uranium from phosphate ores and started setting up the production plant. In Taiwan, a feasibility study of establishing the production plant was started in 1977. A pilot plant was completed, tested, and operated in 1979. The main source material. - phosphate ores is obtained from China Phosphate Company. The annual yield of the pilot plant has been planned to be one ton of ammonium diuranate (ADU). The Health Physics Division of Institute of Nuclear Energy Research (INER), Atomic Energy Council of Republic of China (ROC AEC), is responsible for the radiation safety control of the plant. The purpose of the radiation safety control is to collect radiation safety information of the plant of this type, to evaluate possible radiation hazards to the personnel, and to analyze the radiation safety of the immediate environment adjacent to the plant. Furthermore, the information and experience obtained are used as the basis for applying radiation safety control to the production plant. The main emphases of the radiation safety control are therefore the arrangement of radiation safety control areas and the collection and evaluation of the health physics data. This report includes the past one and half years' experiences of the radiation safety control of the pilot plant, the planning of the production plant with an annual yield of 10 ton ADU, and considerations given in improving the radiation safety control of the production plant. PILOT PLANT AND ITS OPERATION PROCESS The pilot plant occupies an area of 350 m2 and is a two-story rectangular building. Exits are provided by a front and a rear door. An additional small door at the central right side of the building is connected to the maintenance area located outside the main building. The interior of the building is divided into interconnected offices, laboratories and process area (Figs. 1 and 2). A stairway to the process area of the second floor is located in the central part of the first floor. The second floor offices are accessible by the additional front and rear stairways. The main process area of the first floor is furnished with plastic floor, and the second floor with poriferous iron-grid floor. The building is not furnished with centralized air-conditioning system. Individual air conditioners are, however, available to some laboratories. Because the back door of the building is frequently open, the product storage room is provided with a blower to maintain good ventilation. Natural uranium contents of phosphoric acid solution vary in the range from 0.07 to 0.11 kg/m3. The process consists mainly of the uranium concentration cycle and the purification cycle. A flow diagram of the process is shown in Fig. 3. CONSIDERATIONS GIVEN FOR RADIATION SAFETY CONTROL AND THE ESTABLISHMENT OF RADIATION CONTROLLED AREAS The radiation safety control of the pilot plant is carried out on the basis of the considerations listed below:1,2 1) Since the wet process is adopted, and the flow of the radioactive material is confined to closed pipes and containers, air contamination is therefore not too much of concern. 2) The concentrations of radioactive material of the whole process are mostly less than 10 ppm. An exception is the final ADU product after precipitation and centrifugal separation, which contains up to 50% natural uranium. It is therefore necessary to apply radiation safety control to the process area where

Jan 1, 1981

By J. F. Edwards

In situ extraction of copper through borehole injection presents a new technology for the mining of copper. For the successful application of this technology, copper recovery at the surface must be specifically designed for borehole injection and the general conditions of the well field. This paper describes the design of a solvent extraction / electrowinning facility specifically designed for in situ leaching of copper. This design is based on commercial solvent extraction / electro-winning with considerations of the requirements of this specific application.

Jan 1, 1988

By John C. Cook

There is pressing need for better means of exploring ground conditions ahead of mining. Exploration drilling has the drawbacks of high cost and a seriously restricted sampling zone. Traditional geophysical exploration methods including gravity, magnetic and resistivity techniques have been used with some success underground, but all give poor target delineation relative to range, since they depend upon minor distortions of a potential force field. Much greater ratios of resolution to range can, in principle, be obtained by employing electromagnetic or seismic radiation as the exploring agent. This is because propagation time delays can be used to measure range accurately, and to separate the small effect of a distant target from the much larger effects of nearer targets and of the transmitter. Seismic waves have long been used with great success in exploration for petroleum, and recent research on their application underground is promising. Electromagnetic (radar) waves have been very successfully used for detection and location through the air and outer space, and have also explored through polar icecaps more than a mile thick.l It is not generally realized that below the soil many rocks are also somewhat radar-transparent, and that radar can be used for exploring such rocks, once a quarry, a mine, a borehole, or other means of access has been opened. Radar waves are reflected by any boundary or object where they encounter a large change in electrical properties.2 The usual cause of such a change is a difference in moisture content. Radar waves passing

Jan 1, 1972

By A. K. Bakshi

Mineral suspensions show Newtonian flow properties at lower solid concentration, but change into non-Newtonian regime as the solids content is increased. For Newtonian fluids viscosity is independent of shear rate, but for non-Newtonian fluids it varies with rate of shear. Therefore, measurement of viscosity at a shear rate, different from the process will be futile unless the slurry is Newtonian. This is especially true for hydrocyclone operation, where the rate of shear is different at different points within the hydrocyclone. In this case, it is very important to determine the flow type of the suspension before attempting to establish any correlation between viscosity and process efficiency. A new technique to distinguish such changes in flow type has been developed. This involved a co-axial cylinder type viscometer which measured apparent viscosity at a low shear rate, and a vibrating sphere type viscometer which measured the apparent viscosity at a high shear rate. Special precautions were taken to allow measurements of viscosity of rapidly settling mineral suspensions. Because the vibrating sphere viscometer operated at a much higher shear rate than the rotating viscometer, the two instruments together could determine the shear-rate dependency of the viscosity. Ground silica of 80% passing 65~m size in water was used to prepare slurries at concentrations ranging from 1O-70wt% solids. Viscosity of each slurry sample was measured simultaneously by both the viscometers and the results were compared with each other. With this technique, it was found that all the silica slurry samples were in the Newtonian flow regime.

Jan 1, 1995

By W. M. Shaver, R. Letourneau, W. R. Dengler

Dynatec Mining Limited contracted to sink a 1500 metre (4960 ft.) concrete lined shaft for Falconbridge Nickel Mines in Sudbury, Ontario, Canada. The shaft is 6.3 metres (20.5 ft) in diameter inside the concrete lining and is equipped with steel furnishings. Dynatec used the owner supplied 4.6 metre (15 ft.) diameter double-drum hoist to sink the shaft with 12.5 tonne buckets for muck removal and 4 cubic metre concrete buckets for concrete placement. One of the unique features of the shaft sinking operation is the use of a four-boom electric hydraulic drill jumbo permanently mounted in the shaft sinking stage. This paper will describe the performance obtained with the electric hydraulic drilling equipment and the high capacity muck removal and concreting equipment.

Jan 1, 1991

By Emily Wortman-Wunder

Attendees at December?s Arizona SME Section Conference at the Hilton El Conquistador Resort outside of Tucson, AZ were feeling optimistic and ready to get to work after a year of steady growth and recovery in the mining industry. During the two-day event (Dec. 5-6, 2010) and the preceding American Mining Hall of Fame banquet and awards ceremony, the focus was on copper, worldwide population growth and regulatory pressures, with several smart new projects featured alongside updates to traditional large-scale copper development projects. Keynote speaker Timothy Snider, chair of the University of Arizona?s Lowell Institute for Mineral Resources, hit the mood of cautious optimism when he analyzed the global demand for resources, using the case example of copper. Over the next 20 years, he said, the world?s population is expected to grow to 9.2 billion and the average annual per capita copper use is expected to rise from 2.2 to 4.5 kg (5 to 10 lb). The increase in demand will provide tremendous opportunity for mining companies, he said, but cautioned that the opportunities are balanced by negative influences on demand and pressures on supply. While demand for copper is currently growing, Snider noted that there were significant downward pressures on demand as well. These included a western world that is overbuilt, in-creasing use of substitute materials in new construction and the rise of wireless devices. He also noted new regulatory pressures, and pointed out that resource development now had to occur within a context of sustainability on several levels.

Jan 1, 2011

By W. J. Karwoski

A ground-support system for grizzly and haulage drifts was tested in Magma Copper Co.'s San Manuel mine. Eight two-piece, wide- flange steel sets were erected in a ventilation drift on the 2315 grizzly level. The sets were lagged with three different materials and back- packed with pea gravel and sand. The pillar on either side of the drift support system was instrumented with stressmeters and rock-bolt load cells, the backfill with pressure cells, and the steel sets with load cells. Results indicate a better survival rate than with typical monolithic concrete.

Jan 1, 1979

By Leonard Sugin

As we approach the end-of the 20th century we are made more aware of the tremendous role that energy plays both directly and indirectly in our varied way of life. The industralized nations of the world have already established industries and economies which are greatly dependent upon the availability of energy. The underdeveloped and developing nations of the world are slowly and surely moving to the same utlimate requirements. The world wide need for distribution of energy sources is continuing to grow. At the present time there is a great imbalance between the sources of energy and the consuming economies In order to bring about greater equality between supply and demand major efforts and large capital expenditures are constantly being made. Industralized areas are seeking their own independent sources of energy whereas those areas of the world which contain great reserves of energy are limiting its export as well as developing its own industralized capacity. Nevertheless, energy bearing materials are still transported great distances in order to satiate the appetites of power hungry economies.

Jan 1, 1975

By H. A. Stoess

The Minerals Industry makes heavy demands for and on its Material Handling equipment. It also gives progressive management the opportunity for considerable savings, ad consequently increased profits. In some cases, cost of Materials Handling amounts to 40°/o of the total cost of the ultimate product. Handling costs are hidden in overhead, indirect labor, excessive maintenance, productive workers performing handling tasks, and, a great many more. Even though Materials Handling is the oldest occupation of mankind, it is only within the past twenty years that it has emerged as a specialized field. While this industry has made full use of all types of mechanical and vibratory conveyors, pneumatic conveyors in their proper application can be a distinct asset. me use of pneumatic conveyors by this industry however is limited- to a certain extent by the particle size of your products through the various phases of manufacture, as well as their bulk density. However, with increasing knowledge of the fluidization of dry materials, their use is becoming more wide spread.

Jan 1, 1962