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By A. Probst, N. Moores, J. A. Finch

In 1994, McGill University and INCO Ltd. (Sudbury operation) initiated the transfer of technology originally developed to detect levels in equipment ranging from flotation columns to thickeners. A conductivity probe was installed in a concentrate thickener to monitor the mud line and the solids load. The probe consisted of a vertical tube with 32 equally spaced electrode rings connected in pairs to give 31 conductivity cells. Conductivity was measured as a function of depth to produce a conductivity profile. From the conductivity profile, the mud line and the percent solids can be inferred. The probe was installed in October 1994, and it has been successfully detecting profiles since then. This paper includes a description of the incidents that occurred and the experiences gained during this technology-transfer process. Discussed is probe installation and startup; software modifications to accommodate both operating conditions and the needs of the operators; and calibration procedures to adjust to changes in performance as a consequence of long-term use. Also included are preliminary observations of the still-in-progress last stage, i.e., signal interpretation and use to facilitate operation, particularly by providing early reaction to upstream disturbances.

Jan 1, 1999

By K. H. McDaniel, D. M. Loring

The underground ventilation system at the Waste Isolation Pilot Plant (WIPP) provides for the unparalleled ability to ensure the safety of the workers, the public and the environment. Although small spatially, the system can vary the airflow from 31.2 to 217.1 m3/s (66,000 to 460,000 cfm). The system can automatically incorporate HEPA filtration in the event of radioactive contamination. Remote-capable regulators individually control the four main splits, and they can be adjusted from the surface if necessary. A ventilation remote-monitoring and control system provides real-time information. Future areas of concern include DPM compliance, system psychrometry, logic-based real-time mine-ventilation simulation and automation using PLC technology. This paper discusses the evolution of this system.

Jan 1, 2003

By P. M. Soupios

The study of soft soil (wastes above the rock bed) an issue of great importance in civil engineering, is usually addressed by drilling boreholes. This method is rather expensive and time-consuming and although the information obtained is usually accurate, on the other hand it is much localized. Recently published researches have demonstrated the ability of the combination of geophysical exploration methods to estimate the thickness of deposited wastes, which provides the layered structure of the study area and certain, method depended, mechanical parameters as well. By theory, the frequency of resonance of an upper layer is a function of its thickness and the average shear velocity in it. Furthermore, the application of H/V spectral ratios of micro-tremors is a fast, straight forward and cost effective methodology, yielding the determination of the main resonant frequency of the soil. Based on this framework, 20 microtremor measurements have been carried out in a Landfill in Heraklion-Crete. Some of these measurements were deliberately close to drilled sites, where the basement had been reached. Three electrical resistivity tomographies were also used, in order to define the landfill structure such as, thickness, determination of different wastes distribution in the study area and other parameters. In addition, estimation of predictive Vs using empirical relationship between shear velocity and penetration resistance (SPT?s) were also conducted. Knowing the thickness and the resonant frequency, we estimated the shear (Vs) velocity of the waste cover. The final Vs model was confirmed using the results from the Vs-SPT correlation. The combinative implementation of the above mentioned geophysical and geotechnical methods have successfully defined geometrical and geotechnical/geophysical characteristics of the area under investigation in a fast and cost effective way.

Jan 1, 2005

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 Carl S. Vender

Knife River Coal Mining Co.'s Beulah Mine is a multiple-seam lignite operation located in western North Dakota. The mine began production in 1963 with annual production of 450 kt (496,000 st). It now produces 2.2 Mt/a (2.4 million stpy). As development progresses, operations advanced into more complex geologic areas. Various techniques have been analyzed to maximize coal recovery in a cost-effective manner. Additional studies are ongoing to determine what changes will be implemented as deep, wet sands are encountered in the reserve area. Knife River Coal began as an underground operation in 1924 at Beulah, 120 km (75 miles) northwest of Bismarck. In 1950, the operation converted to a combination underground and surface mine. The underground segment was closed in 1952. Development of the existing reserve area south of Beulah began in 1963. About one-fourth of the acreage under permit (Fig. 1) is sufficient for 10 years at current production rates.

Jan 1, 1991

By Peter J. Suardini

Over the last few years, researcher have been working on improving procedures for fine-coal (minus 150 microns) washability analyses. The effort was stimulated by past difficulties in obtaining accurate and reproducible results from the various commercial laboratories providing fined washability services. This paper contains the results from fine-coal washability testing, performed by Process Technology, Inc. (PTI), as part of a U.S. Department of Energy (DOE)-sponsored project. The testing focused on comparing the performance of a number of media options (i.e., aqueous solutions and organic solvents), as well as evaluating the impact of a number of procedural steps on separation performance. The paper summarizes PTI's recommended washability procedures for various size fractions and ranks of coal, and makes recommendations for future studies of certain phenomenon, such as void penetration and particle density changes, which are not well understood.

Jan 1, 1995

By E. F. Schnitzer, C. Lidstone, D. Cramer, P. J. Wampler

The River Island mining site is located at approximately river mile (RM) 15 on the Clackamas River, a large gravel-bed river in northwest Oregon. During major flooding in February 1996, rapid channel change occurred. The natural process of meander cutoff, slowed for several years by dike construction, was accelerated by erosion into gravel extraction ponds on the inside of a meander bend during the flood. In a matter of hours, the river cut off a meander and began flowing through a series of gravel pits located on the inside of the meander bend. The cutoff resulted in a reduction in reach length of approximately 1,100 m. Erosion by bed lowering, knick point retreat and lateral erosion of upstream river banks occurred quickly. Within two days of the peak flow, 3.5 hectares of land and 105,500 m3 of gravel were eroded from the river bank just above the cutoff location. Much of this gravel moved a short distance downstream into the excavation. Reach slope increased from 0.0022 to approximately 0.0035 in the cutoff reach. Between 1996 and 2003, the knick point from the meander cutoff has migrated 2,290 m upstream, resulting in increased bed load transport, incision, and local lowering of the water table. In 1993, prior to the meander cutoff, transects were surveyed in the River Island reach upstream of the cutoff location. Resurvey of these transects and aerial photo analysis indicates that 96% of the knick point migration occurred during the first winter following meander cutoff. Connection of the flowing river to the off-channel ponds has had minimal effect on water temperatures in the mainstem Clackamas River. It is likely that this minimal change in temperature will decrease as ponds are isolated from active river flow by gravel bar deposition. Fish net-ting in spring 2002, suggests that salmonid use of the pond in the spring is minimal. The most abundant native species netted were large-scale sucker and northern pikeminnow. The most abundant non-native species netted was brown bullhead. Early regulation by state and federal agencies did not adequately evaluate potential impacts to the river and the floodplain; nor did it evaluate future impacts related to geomorphic processes and sediment transport. New permit evaluation methods, currently implemented by both Oregon and Washington, incorporate 1) river dynamism through historic river migration analysis; 2) stability of human structures in light of river dynamics; and 3) sediment transport and its impact on channel stability and dynamics. The gravel pit capture at River Island highlights the potential risks of mining in an active secondary channel of a large gravel-bed river. Mining deeper than the depth of the adjacent channel, within the active migration zone, may increase off-site impacts. In locations where multiple gravel excavations are present within the meander zone, a comprehensive reclamation and restoration plan should be developed which provides long-term channel stability within the natural variability of the entire river reach.

Jan 1, 2006

By G. Y. Li, D. Farahmand

The dilemma of a numerical analyst not only concerns the problem of modelling the non-linear behaviour of intact rock, but also the non- linearity contributed by structural discontinuities. In this light, it is the intention of this paper to examine some aspects of the non-homogenity and structural discontinuities of rock and incorporate this behaviour into boundary element numerical solution. Non-homogeneous material is considered piecewise, thus homogeneous and is modelled by using sub-regions. The Mohr- Coulomb failure criterion is employed to model the non-linear behaviour of the major discontinuities. A computer program is developed based on the procedure for combining the direct boundary element method and the displacement discontinuity method. A linear element type is employed in the formulation of numerical solution. The computer program is used to study the stress distribution in a gold mine.

Jan 1, 1986

By J. C. Barker

Alaska, with about 74% of the US continental shelf, is largely unexplored for placers in its vast shallow marine waters. Nevertheless, there are numerous occurrences of marine minerals including gold, platinum, and cassiterite. Offshore dredging has recently begun in the Nome area. State and Federal agencies are preparing additional acreage for leasing. With 76,200 km (47,300 miles) or 54% of the US coastline, Alaska is a vast, largely unexplored frontier for shallow-water marine placers. Despite the general lack of mapping and only sporadic past prospecting, many prospects are known and a major mining operation for gold has recently begun offshore of Nome. Due largely to the demonstrated success of the Nome operation, the US Minerals Management Service is preparing to conduct a lease sale of additional acreage further offshore from Nome. And future sales are being considered elsewhere by both the Federal and state leasing agencies.

Jan 1, 1990

By Shahzad Moosa, John M. Pitt

Statistical variability in rock strength can be evaluated by rapid, inexpensive ultrasonic pulse velocity measurements, an important consideration since rational probabilistic design in rock is often hampered by the cost of obtaining sufficient strength data. Experimental ultrasonic pulse velocity measurements on a set of 96 limestone specimens showed two distinct statistical populations. Both populations followed Weibull distributions, with flexural strength distributions paralleling pulse velocity distributions. Thus, experimental results suggest that strength variability may be predicted from a few rationally selected strength measurements and several ultrasonic tests. The correspondence between strength and velocity may then be used to develop an experimental transformation function, allowing the development of a statistical distribution function for strength based on the known statistics of velocity. Comparison of experimental groups with full sets of corresponding strength1 velocity data showed the technique offers a fairly accurate description of the statistics of strength.

Jan 1, 1986

By J de Cuyper, S. R. Rao, J. Leja, K. S. Moon, W. Freyberger

A prolonged grinding of sulphide ores in steel mills appears harmful to flotation recovery and selectivity whenever xanthates are used as collectors. Particles finer than about 10um show a pronounced decrease in floatability. A supposition was made that the cause of the reduction in floatability of ground sulphides is the presence of metallic iron abraded during grinding and deposited on the ground particles. Electro- chemical measurements were made of mixed potentials developed by different sulphide-mineral electrodes (galena, chalcopyrite, pyrite, marmatite, pyrrhotite) in xanthate solutions, without a direct con- tact or in contact with a metallic iron electrode. These measurements showed that without a galvanic contact between the sulphide and the iron, the values of mixed potentials were in the vicinity of the xanthate/dixanthogen redax potential. When contact with iron was established, the mixed potentials shifted towards the more negative reducing or cathodic values, The shift was greater the higher was the ratio of the surface areas: iron electrode to sulphide electrode. Further, the shift in mixed potentials was greater the more reducing were the conditions on the sulphide electrode. Chemical analysis of reaction products produced on the surfaces of sulphides and in the bulk solution showed that less thiosulphate was formed in all of the sulphide-xanthate systems and that more elemental sulphur was detect-

Jan 1, 1976

By J. M. Mutmansky, A. Wang

This paper defines the elements of a basic economic model for decision making when considering a methane drainage system for an underground coal mine. A drainage system entails significant capital and operating expense; hence the decision to utilize drainage must be made carefully. The model outlines the basic structure of decision making and considers the costs and benefits when the methane is marketed and when the methane is vented to the atmosphere. The effects on mine safety and the dust levels in the mine are also considered, both in a general format and as economic variables. Sources of information for executing this decision making are provided for an actual mine decision.

Jan 1, 1999

By W. T. Plummer

• The SuperBowl is a fluidized bed, semi-continuous, enhanced gravity separator for gravity gold recovery. The market for this type of equipment has, until recently, been dominated by a single supplier. Many mineral processors have encouraged the SuperBowl designers to develop competitive equipment for obvious reasons. • The primary beneficiary of competition in this field will be the mineral processing community because legitimate competition fosters continuous improvement in product and price.

Jan 1, 1996

By D. W. Smellie

This paper is a review of technological progress in mining geophysics during the past decade. This has been the most significant period in the history of mining geophysics. Among the already existing; techniques, instruments for ground -magnetic and electromagnetic prospecting, were developed that are more, portable and faster to operate. Induced polarization equipment came into widespread use. Airborne instruments of various types became available and were used to survey large areas. Drillhole instruments were developed and have had some use, and it is to be hoped will be used to a greater extent in the future. Two revolutionary new methods, the AFMAG and INPUT, were developed. The wisdom of attempting to cover such a broad field in a single paper might be questioned. There is the inevitable problem that each topic must be discussed very briefly. However, while papers describing individual instruments have appeared, many have yet to be described in the technical literature. The evolution of the ground magnetometer and electromagnetic instruments has not been discussed. It is only recently that a review article has appeared on airborne EM. The existence of review literature on some topics has meant that they are given less emphasis in this review than those topics inadequately covered. It will also be observed that stress is laid on "chose instruments that are generally available to the mining industry rather than those developed by individual exploration companies for their own use.

Jan 1, 1963

By R. Timothy McCrum

It is not often that the Interior Department's Bureau of Land Management, Office of the Solicitor, and Interior Board of Land Appeals (IBLA) jointly act to do the mining industry a good turn. That happened, however, in the recent decision, Schlosser v. Pierce, 92 IBLA 109 (1986). It was ruled that the theorized "independent mine requirement" was not a part of the discovery standard for mining claim validity under the 1872 Mining Law. The phrase "independent mine requirement" would require the mineral reserves within the boundaries of each individual mining claim in a claim group to support an independent economic mining operation. This, without regard to the fact that reserves on adjacent claims could be mined in a group operation, resulting in greatly reduced mining and marketing costs per ton of ore. Such a rule would render invalid under the 1872 Mining Law mining claims for almost all low-grade, high-tonnage, commercially valuable mineral deposits. Until the Schlosser case, no judicial or administrative decision had addressed the issue of the independent mine requirement. Nonetheless, a series of Interior decisions in the 1970s implied such a rule. Even the Rocky Mountain Mineral Law Foundation reluctantly concluded in 1984 that, "each claim to be valid must be capable of being operated at a profit independently of any other claim," the Foundation did criticize the rule as "excessively stringent" and urged the adoption of a "more realistic rule." Fortunately, the IBLA did just that in Schlosser when it ruled that the "application of a requirement that each claim be independently capable of being mined and marketed at a profit is rejected," 92 IBLA at 134. Now, a year after the 1986 decision, there remains some unwarranted confusion over the issue resolved in, and the meaning of, the Schlosser decision. There is no need for this confusion. The Interior Department's decision is a clear and legally sound victory for the mining industry. Grazing rights vs. mining claims The Schlosser case was an unusual mining claim contest. A private contest was brought before the Interior Department. Schlosser was a federal grazing lessee and surface owner. He filed against Pierce, the locator of a group of mining claims for bentonite over the same lands. At a hearing before interior's administrative law judge (alj), Schlosser's counsel began laying the foundation for the independent mine requirement. Counsel asked the mining claimant's expert whether he would go through the permitting procedure, road building, and reclamation just to mine the amount of bentonite on any one claim in the group. Schlosser's counsel proceeded with this line of questioning for each of the 16 claims in the group. Pierce's mining expert testified that the tonnages of mineral on any individual claim could not be mined, processed, and marketed at a profit if only one individual claim was considered. However, if the claims in the group were operated jointly, all the mineral could be mined, processed, and marketed at a profit.

Jan 8, 1987

By Conrad W. Steller

What is the definition of a successful construction or development project? It could be described in many ways: a project that performs as designed; a project completed on time, a project completed within budget. The title of our talk today is, "The Advantages of Applying Design/Build -Construction Management to the Mining Industry." As our talk develops, you will see that rather than tell you how to apply this concept, we will discuss the advantages and details of Design/Build so that you can independently apply the concept. Design/Build is not new, and it cannot be universally applied. It has, however, within the past ten years, carved a specific and substantial place in the overall construction -development market. The reasons for its rather recent rise to considerable prominence as a concept is due, in part, to the increasing urgency of gaining productive access of a production facility and, in part, to the inherent advantages of the concept's economics--and they are considerable. If the Design/Build concept of contracting were fully understood, it would, without exception, be the favored way for private industry to contract for its new construction and development as well as renovation work. The basic advantages are: earliest possible access and completion at the lowest cost. Design/Build is often equated and compared to "fast track" or "turnkey" methods of construction. The Design/Build concept can, in fact, be both of these or neither. "Fast track", in and 6f itself, implies that the project will be phased construction, that is to say, it will be built quickly; whereas I "turnkey" is a measure of the completeness of the project, usually meaning essentially that the

Jan 1, 1977

By F. C. Bond

Nature of Empirical Calculations The size reduction of large tonnages of ore and rock is an operation of great magnitude. It is a necessary and important part of industry. Its development has been motivated by practical need and has followed the path of an industrial art without much help from theoretical science. Knowledge has been accumulated from experience. Trial and error established the methods; then collected data were tabulated and served as the basis for empirical equations that have been continually modi¬fied and amplified as new data became available. These equations now constitute the bulk of our present knowledge of comminution. There is no accepted scientific theory that is basic to comminution. In electrical, mechanical, and civil engineering, as well as in many other industrial activities, such theories exist and are extremely help¬ful, but rock is essentially heterogeneous, and the zones of weakness that control its breakage are thoroughly diversified. No theory has yet been discovered which can account for the variability of rock, although many attempts have been made. Empirical equations tell nothing of the why of a phenomenon, but if they are properly derived they can tell much about the how. They always represent only an approximation of behavior but never a law. In a proper empirical equation a symbol is assigned for each of the variable quantities that obviously affect the relationship. In a grinding mill these include mill diameter, mill speed, and feed rate among them. In setting up and revising an empirical equation the cardinal princi¬ple in establishing and modifying it is this: any change must be strictly ascribed to the variable which caused it. A useful empirical equation is rendered useless when a change in any convenient coefficient or exponent is made to make it fit a particular set of data, without certainty that the altered coefficient or exponent is the responsible variable in the new data. Such indiscriminate revisions have brought the use of empirical equations into some disrepute. When existing equations are changed to accommodate new data it is a good rule to make a change which gives results intermediate between the new and the old. A halfway point is usually a good choice.

Jan 1, 1985

By Vi-Duong Dang

Lithium requirements in the next few decades for batteries and controlled thermonuclear fusion reactors (CTR) may exceed the availability of the current mineral and brine reserves. It is thus prudent to search for new reserves and resources to satisfy these and future lithium applications. The lithium content of the waters from the Smackover oil field. located in the Gulf Coast region of the United States, ranges from 100 to 500 mp/l and could represent a substantial new reserve. Experimental evidence described in the literature indicates that a specific chelating agent dipivaloylmethane (DPM), of the diketone type, has a specific selectivity toward lithium in the presence of other metal ions in aqueous solutions. Based in part on this unique property of dipivaloylmethane, a conceptual design of a full-size plant to extract lithium from the Smackover brine is presented in this paper. This study includes alternate flow-sheet development, design information on the major units of the process, energy requirements, and an economic analysis of a facility capable of producing 106 kg of lithium per year. The economics of three different process concepts depend primarily on the amount of water needing to be evaporated from the initial oil-field feed waters in concentrating the brine. The results, as a function of production rates, are indicated only in a general manner.

Jan 1, 1978

By J. A. Finch

The use of pneumatic methods for measuring interface level in flotation columns is analysed. It is shown that errors can vary over a wide range (e.g. 40 cm. in one industrial application) depending on bubble size, particle size, bubble loading, liquid hold-up and bulk slurry density. Accurate measurements (+ 5 cm) can be obtained by measuring intensive properties of the froth near the interface. Methods based on the measurement of temperature and conductivity are described and analysed. Control of the interface level using these measurements subject to various disturbances is demonstrated.

Jan 1, 1988

By J. Abbott

This paper gives a brief description of the Compania Ninera del Pacifico (CNP) a subsidiary of the Campania Acero del Pacifico (CAP), its participation in the Chilean Iron Ore mining and the gradual development of its activities. mainly in this paper, it is explained the CNP experience in the production of 34 million tons of self-fluxing pellets for Blast Furnace in a period of ten years in its Huasco Pellets Plant.

Jan 1, 1989