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Mount Isa mine is the largest underground mine in Australia and is located 2,000 kilometres north-west of Brisbane. This mine has been in continuous operation since 1931 and in 1986/87 the silver/lead/zinc stream achieved the peak annual mining rate of 4.7 million tonnes. At present about fifteen different steeply dipping stratiform orebodies are being mined to maintain an annual production rate of around 3.0 million tonnes. Out of these, only two orebodies (2 & 5) are amenable to sub level open stoping (SLOS) type bulk mining methods. This year only 150,000 tonnes are scheduled from pillars and remnant areas but in future, more sources will be required to meet the budget production targets.

Jan 1, 1990

By Brian H. Zelenko, Patricia M. Perry

INTRODUCTION The environmental requirements of the next section of Washington, D.C. METRO subway tunnels present unique challenges to the Contractor. The 14th Street Tunnels contract includes twin 975 m (3200 linear ft) soft ground tunnels. A stringent environmental soil and groundwater monitoring and free product recovery program was specified by the owner. A project-wide dewatering program hinges on satisfactory completion of the environmental requirements. Implementation of the Contractor's environmental program is discussed, including the pros and cons of the program, as they relate to progress of the project. Environmental issues on tunneling projects have become an important part of the urban tunnel construction process. Delays associated with environmental issues can have a major cost impact on tunneling projects. This paper will discuss the first of five Washington Metropolitan Area Transit Authority (WMATA) tunnel and station contracts awarded in 1994. These contracts are part of WMATA's Fast Track Plan to complete the original 166 km (103 mile) system by 2001. As such, stringent environmental requirements have been specified as a part of these contracts to limit delays associated with local regulators in order that the tunnels may be constructed on schedule.

Jan 1, 1995

By John P. Harmon

This paper was written with two objects in view: (1) To describe in detail what has been done toward the ventilation of the main unit of the Portovelo mines and the results; (2) to give information that may be useful to anyone who may have to make a preliminary mine ventilation survey, with recommendations for the improvement of the existing system and finally the maintenance of the improved system. General Description The mining operations of the South American Development Co. at Portovelo, Province of El oro, Ecuador, are described here only briefly, as a full discussion does not fall within the scope of this paper. The orebodies are of the steeply dipping, gold quartz vein type, averaging about 2.0 meters wide. As shown in Fig. 1, the ore chutes are relatively far apart, making considerable development work necessary before connecting raises can be driven between the levels. Faulting' on a large scale and a parallel vein system have made long dead-end drifts and many crosscuts necessary in the exploration of veins. The ventilation of these dead ends is described under Auxiliary Ventilation. The method of mining2 is the filled rill stope method, similar to the method that is largely employed at the Butte mines. The main shaft of the mine is in the Amarillo Valley, on either side of which mountains rise abruptly to a height of several hundred feet above the collar of the shaft. Entrance is made to the mine: (1) Through the American shaft, which extends vertically from the surface to a depth of 1100 ft., of which only the first 700 ft. are in active use at the present time; (2) levels are driven from the American shaft at intervals of 30 m. (100 ft.), of which only the third, fifth and seventh levels need be considered in the ventilation problem; (3) adits at intervals of 30 m. (100 ft.), with a few exceptions, above the collar of the American shaft.

Jan 1, 1931

The future of the United States (US) mining industry will be affected greatly by recent coal mining disasters. These have resulted in new legislation which will have an impact on mining economic costs as well safety and health of miners. This paper discusses the changes that new legislation and regulations are making to the industry and current research that is producing technologies to make mining safer and will likely impact the future of mining.

Jan 1, 2008

By H. Baldauf, H. Schubert

The structure of flotation reagents is important for their adsorption on mineral surfaces and thus for their flotation effectiveness. The influence of the structure of organic depressants on the flotation of fluorite and barite with anionic and cationic collectors was investigated using a modified Hallimond microflotation cell. In addition, adsorption, desorption, and electrokinetic results were employed to further elucidate the role and the correlation of the structural parameters for adsorption and the depressing effect. As hydrophilic reagents, different aliphatic and aromatic compounds capable of forming chelates with alkaline earth materials were used. For the depressing effect, the kind, number, and position of the polar groups in the molecule, as well as the structure of the reagent films play decisive roles.

Jan 1, 1980

By G. Osuch, G. Derge, G. M. Pound

Using a new dternating-current potentiometer circuit and a specially designed four-terminal cell, the specific conductance of molten Cu2S-FeS mattes was measured as a function of temperature, from the liquidus to 1500°C, over the complete range of composition. The high conductivities, about 1500 ohm-I cm-l for FeS and 100 ohm-l cm-l for Cu,S, indicate that the conduction is electronic rather than ionic. Molten FeS has a negative temperature coefficient of specific conductance, resembling metallic conduction. Molten Cu,S has a positive temperature coefficient, resembling semiconduction. The binary roughly follows an additive rule of mixtures with respect to both magnitude and temperature coefficient of specific conductance. Metallic bonding in the liquid is postulated to explain these phenomena. MUCH has been learned in the past about the nature of liquids and the ionic or molecular species in solution by means of electrical measurements. Thus, dielectric constants','2 have given information about molecular liquids such as water and benzene. Measurements of dielectric constant usually are impossible in electrically conducting liquids, such as aqueous solutions of ionic salts and molten ionic salts. However, measurements of electrical conductance and ionic transference have provided much knowledge about the latter systems.a-" In recent years, the ionic nature of certain molten metallurgical slags has been established by Derge and Martin7 through electrical conductance and electrolysis measurements. Chipman, Inouye, and Tom-linsonq ave studied the electrical conductance of molten FeO and report a high specific conductance of about 200 ohm-' cm-' (compared with 4 ohm" cm-' for an ordinary ionic liquid such as molten NaCl) and a positive temperature coefficient of conductance. They interpret these results in terms of p-type semiconduction by analogy to the situation in solid FeO.Y imnad and Derge" have studied cell efficiency in the electrolysis of molten FeO-SiO, systems and conclude that ordinary ionic conductance increases with SiO, content. Very recently, interest has been revived in the electrical conductance of liquid metals and liquid metallic solutions. Scala and Robertson1' report a close resemblance between the liquid and solid states with respect to thermal, structural, and compositional relationships. Molten sulphides have not received a great deal of attention. Bornemann and von Rauschenplat" measured the specific conductance of molten Cu2S as a function of temperature with a four-terminal cell using direct current. A high specific conductance and a positive temperature coefficient were found in that investigation." Using a two-electrode apparatus, Savelsberg" electrolyzed various molten sulphide mixtures. He concluded that pure molten Cu,S and FeS were electronic conductors but that the mixtures exhibited some ionic conduction. In the present investigation, the specific conductance of the industrially important Cu-Fe sulphide mattes was measured as a function of temperature and composition in order to investigate the mode of electrical conduction and the structure of these molten mattes. An alternating-current circuit was used to eliminate the effect of any possible electrode reactions. Apparatus The Conductance Cell: Due to the high specific conductance of the systems studied (10' to 10" ohm-' cm-'), the classical two-terminal cell and Wheat-stone bridge apparatus could not be used. A four-terminal cell was developed in order to eliminate lead resistance, and an ac potentiometer circuit was designed to give rapid and sufficiently accurate measurements of the cell resistance. A diagram of the conductivity cell is given in Fig. 1. The molten matte is contained in a dense alundum crucible, and spectrographic graphite rods that dip into the molten matte serve as the four conductance terminals. Two of the graphite rods on opposite sides of the cell serve as current-carrying leads, and the other two graphite rods are null-current probes that detect the potential drop across the cell. These graphite rods are contained in silica tubes, and the lower constricted portions of the two silica tubes define the column of liquid whose electrical resistance is being measured. The electrical resistance of the broad ex-

Jan 1, 1956

By Alfred F. Beasley

The slags derived from the smelting of lead and copper ores are composed essentially of silicates. The problems arising from the smelting of these ores consequently involve the study of silicate fusions. In the absence of specific knowledge concerning the compounds occurring in slags, it has been the practice of metallurgists to treat them in terms of their total chemical composition. Slags have been classified as monosilicates, bisilicates, sesquisilicates, and subsilicates according to the relative amounts of oxygen in the acid and basic radicles of the hypothetical salt produced. While this has been a useful guide to metallurgists in computing the furnace charges, it falls far short of a basis for the scientific investigation of slags. In order to understand the nature of a slag as a whole it is necessary to learn the physical and chemical properties of the mineral compounds which go to make up that slag. The efficiency with which an ore is smelted in a furnace depends primarily on the physical properties of the compounds formed during the operation. When the melting points and fields of stability of each of the mineral compounds in slags have been established, it will be possible to determine the properties of any given slag by examining the nature and amounts of its mineral constituents. Earlier Investigations In 1884 and succeeding years an extensive survey of lead and copper furnace slags was made in Europe by Vogt, and a large part of the present knowledge of the subject is due to his publications.' Vogt's interest in artificial fusions was directed primarily towards the explanation of problems in igneous and economic geology and his subsequent works have been confined wholly to that subject.

Jan 1, 1930

By S. Yukawa, M. J. Sinott

The low solubility of bismuth in copper and its segregation at copper grain boundaries with resulting embrittlement is well known.1-3 The heterogeneous diffusion of liquid bismuth into polycrystalline copper has also been studied.4 This work presents some further observations on these phenomena using high-resolution auto radiography to detect the presence of bismuth in copper polycrystalline and bicrystal specimens. The auto radiographs were made by the stripping film technique which produces an autoradiograph that is intact with specimen surface and can be examined simultaneously with the under-lying microstructure. The details of the technique have been described previously.3 In one series of experiments, high-purity copper was alloyed with 0.02 to 0.03 wt pct radioactive bismuth obtained from the Oak Ridge National Laboratory. Melting and casting was done under a

Jan 1, 1960

By Eugene McAuliffe

The mining press, as well as certain federal and state bulletins, refer from time to time to the relative hazards that attach to loading bituminous coal by hand when compared with the so-called "mechanical loading" process. Much of the coal coming under the head of hand-loaded coal is won in part by the use of machinery; the coal-cutting machine is in general use, the electric power drill employed to a lesser extent. Therefore it may be said that the principal difference in the process employed, mechanical loading versus hand loading, lies in the fact that some type of loading machine is employed in the mechanical loading process to lift the coal from the face of the room, place or entry, after it is mined, placing it in the pit cars for transport to the tipple. It is a common practice to compute accident records on the basis of tons mined per fatal and per nonfatal accident, disregarding the fact that it is possible to produce by the aid of coal-loading machines the same daily, monthly and annual tonnage with a much smaller force than is required where the coal is all shoveled by hand. Inasmuch as the men who are released by the substitution of machinery for hand labor must find employment elsewhere, suffering some measure of hazard in their new occupation, we are of the opinion that the true relative hazard that attaches to the processes of mechanical loading and hand loading can be determined only by using as the basis of comparison "man shifts worked" or "hours of exposure" experienced per accident. The Union Pacific Coal-Co., beginning with the year 1929, undertook to maintain a true record of man shifts worked per compensable accident, giving equal weight to fatal and nonfatal accidents. Accidents lacking sufficient severity to come under the compensable terms of the Workmen's Compensation Act were not included in the compilation, the Act providing that "no compensation, except the expense of medical attention, shall be allowed for the first seven (7) days of disability, unless the incapacity runs beyond the period of twenty-one (21) days, in which case the compensation shall run from the time of the injury." With the further thought that all accidents suffered by employees engaged in any service, in or about the place where the loading process

Jan 1, 1931

By C. A. Allen

"The problem of signaling to the hoisting engineer from a moving cage in the shaft has been considered by many mine operators for a number of years. There are several methods in use in different mining districts, and so far as the writer is aware they have been further developed in Utah than in any other state. The latest installations are of interest because they use a very low-voltage circuit for the shaft wires and also because the wiring can be so arranged that the hoist can be stopped from the cage, if so desired.The first installation in Utah was in the shaft of the Centennial-Eureka mine under the management of C. E. Allen. It was placed in operation in the summer of 1899, end has been in continuous and satisfactory operation for 21 years. The arrangement consists or two bare wires down the shaft carrying a current at 60 volts potential, with a device on the cage for making connection between the two wires. This device is simply a short piece of wire which is thoroughly insulated from the cage and is operated by a short lever. Whenever the cage rider wishes to signal the engineer he pulls down the lever, forcing the short wire out against the two bare wires, thus making a circuit which rings the bell in the hoist-room. A similar device was planned in the Grand Central shaft at Mammoth, Utah, but was later abandoned. The cause of failure was reported to be that the shaft was very wet."

Jun 1, 1920

By Raphael Mourad, Colin R. Phillips

Fluorescence, radioluminescence, phosphorescence and thermoluminescence in TLD 100 and 700 are discussed and compared. The energy budget in thermoluminescent material is presented in general terms. Results of measurements of radioluminescence, phosphorescence and thermoluminescence in LiF:Mg irradiated with [a] radiation, using simple facilities, are presented. The calculated energy budget in the exposed chips using [a] radiation is compared to published data using [y] irradiation.

Jan 1, 1981

By J S. J van Deventer

Geopolymerisation is a new technology that processes and transforms aluminosilicate minerals into mechanically strong and chemically stable products. In this investigation, minerals such as fly ash and kaolinite were used as the solid raw materials for geopolymerisation. Inorganic salts were added to the geopolymeric pastes to simulate ionic contamination during processing for building and construction applications. The resultant products were examined and characterised physically. It was found that the early strength development of geopolymeric pastes could be changed according to the nature as well as the extent of the contamination. At a small dosage, the effect of the contamination on the early geopolymeric system depended heavily on the nature of the artificial surfaces that were created in the geopolymeric solution through the addition of the chemical additives. For example, the samples containing MgCl2 and Mg(NO3)2 had shown the same yield stress developments due to the similar surfaces that were formed. The cations of these salts were expected to hydrolyse and form magnesium hydroxide precipitates immediately after the addition to the early geopolymeric systems. The calcium cations of CaCl2 also precipitated upon addition, but the nature of the surfaces of these hydroxides was quite different to those of the magnesium hydroxides and gave rise to different yield stress development. The samples that contained the insoluble salts (in water) demonstrated different yield stress development when compared to each other because of the different nature of the additive surfaces that were exposed to the geopolymeric solution. These results suggested that heterogeneous nucleation could be responsible for the change of the rheological behaviour upon inorganic salt addition. When the extent of the ionic contamination was large, the anions released from the insoluble salts (in water) changed the nature as well as the concentration of the geopolymeric solution and the setting processes were retarded. Oxides, in general, behaved very differently from other salts, indicating the uniqueness of the oxygen anions in a system rich in hydroxyl and silicate anions. The inorganic salt contamination in geopolymers did not show any significant signs of structural change according to the XRD diffractograms collected. The seven-day compressive strength was not lowered by the inorganic salt contamination and it could sometimes be beneficial to the product performance, for example, an increase of 20 MPa was induced by the addition of calcium oxide. Inorganic salts as chemical additives have demonstrated the potential to modify setting times of geopolymers without sacrificing much of the productsÆ strength and integrity.

Jan 1, 2000

By J. D. Mote, A. Rosen, J. E. Dorn

The effect of strain rate and temperature on the critical resolved shear stress for (1100) [1120] prismatic slip was determined for the intermediate hexagonal phase containing about 67 at. pct Ag and 33 at. pct Al. Whereas the flow stress increased only slightly as the test temperature was first decreased below room temperature, a rapid increase inflow stress was obtained with yet greater decreases in temperature from about 240" to 4°K. The effect of both temperature and strain rate on the flow stress over the low-temperature range could be completely rationalized in terms of the Peierls mechanism when the deformation is controlled by the rate of nucleation of pairs of kinks. A few years ago Mote, Tanaka, and Dorn1 observed that the critical resolved shear stress for prismatic slip of a 67 at. pct Ag plus 33 at. pct A1 hexagonal intermediate phase by the (1100)[1120] mode decreased precipitously as the test temperature was increased from 4" to about 160°K. Their results for both basal and prismatic slip are given in Fig. 1. It is obvious that only the flow stress for prismatic slip is strongly temperature-dependent, whereas the flow stress for basal slip is independent of temperature. If the temperature dependence of the flow stress were primarily due to interstitial impurities, it might be expected that they would influence the flow stress for basal slip as well. Since the activation volume at 115°K for prismatic slip was determined to be about 15b3, where b is the Burgers' vector, this thermally activated deformation process was tentatively ascribed as being due to the Peierls mechanism. But the various analyses of the Peierls mechanism then available as formulated by Seeger2 and also by Lothe and Hirth3 did not agree well with the experimental data. Since that time a more realistic theory for the operation of the Peierls mechanism under conditions where the strain rate is determined by the rate of nucleation of pairs of kinks has been presented by Dorn and Rajnak.4 The present investigation was, therefore, undertaken in order to provide the essential data for a careful check on the agreement between this theory and the low-temperature deformation by prismatid slip of the above-mentioned Ag2A1 intermediate phase. EXPERIMENTAL TECHNIQUE Single-crystal specimens so oriented that the [1120] direction and the normal to the (1100) plane were at 45 * 2 deg to the tensile axis were grown from the congruent melting composition of about Ag2Al for the intermediate hexagonal phase by the

Jan 1, 1964

By H. H. Rachford, and J. D. Rice

The effectiveness of digital computing machines in making technical calculations depends on how well the work is arranged to utilize the capability of the machines. This note presents a particularly useful way of calculating hydrocarbon vapor-li.quid equilibrium in the flash vaporization (or condensation) system. The method is well suited to sequence-controlled computing equipment. It is not limited to equilibrium calculations and may be used for solution of most implicit equations in one variable. INTRODUCTION There is increasing interest in the use of electronic digital computers in research and engineering calculations. This is a fortunate and inevitable trend in view of both the increasingly extensive numerical work which is becoming a routine part of many daily production operations and growing demand for the overwhelming amounts of calculations required by newly developed numerical methods for solving heretofore unsolved problems. Machines are in many ways ideally suited to the task but of necessity present certain difficulties. for a particular poblem to be solved must often be formulated quite differently from the way it would be arranged for manual solution. This is done in order to take advantage of the inherent speed and precision of electronic computers and at the same time to limit the need for number storage to the capacity of the machine. Therefore, this note is submitted to present a general and quite powerful method of finding solutions of the frequently encountered implicit equation: F(x,y1,y2,...ya)=0.......(1) where the root, x, is to be found for a given set of y1, ... yn.. The procedure is well suited for use with computing machines, for it usually requires but little storage or programming beyond that necessary to evaluate F. HYDROCARBON EQUILIBRIUM The method is described in terms of the problem it was designed to solve, i.e., the calculation of hydrocarbon vapor-liquid equilibrium in flash vaporization. Given the composition of a hydrocarbon mixture and appropriate values of the equilibrium ratios K, to find the phase ratio and compositions in a closed system: let z, be the mol fraction of the i-th component in the mixture. If K, is the ratio yl/xl, where y, and x,

Jan 1, 1952

By Corale L. Brierley

Bioheap leaching, commercially applied for secondary copper ores and agglomerates, is rapidly gaining popularity. Bioleaching of chalcopyrite concentrates is imminent. Copper bioheap leaching encompasses the bioleaching of acidified and agglomerated coarse, secondary copper ore, stacked on permanent or on/off pads. The stacked ore is irrigated with raffinate containing bacteria. LME-grade cathode copper is produced by SX/EW. Low capital and operating costs, rapid start-up, environmental benefits, operational simplicity and a good performance record make bioheap leaching an attractive technology. This paper looks at the state-of-the-art of copper bioheap leaching and chalcopyrite concentrate leaching, the risks, the benefits, costs, bioheap performance and the future prospects of copper bioleaching.

Jan 1, 1999

By D. M. McFarland

A FEW years ago a novel electric detonator known as the split-second or millisecond delay electric blasting cap was introduced for use in quarry blasting. Regular electric blasting caps fired in series may be depended upon to fire within a millisecond or so from the first to the last in a series. Regular delay electric blasting caps are provided that fire one period after the other period in intervals of 1/2 to possibly 1 l/2 sec. Most split-second or millisecond delays are designed to fire one period after the other period in possibly 25 to 50 millisecond intervals. The ear is not capable of detecting time intervals of this magnitude.

Jan 11, 1950

By A. Sacit Saydam

"Induced polarization/resistivity and magnetometer surveys have been carried out over the Casmo molybdenite deposit in mountainous terrain of northern British Columbia. Molybdenite occurs in quartz-bearing fractures with or without pyrite along a zone of hydrothermal alteration and intense fracturing, believed to be a northerly dipping fault zone, within medium-grained equigranular and porphyritic quartz monzonite.The molybdenite-bearing zone is characterized by a significant resistivity low, a metal factor high and a subtle IP low flanked by highs outside the mineralized area. Magnetic trends, indicated by a magnetometer survey, generally parallel the zone and strike direction of the different intrusive phases, and have been helpful in delineating contacts and faults in the area.IntroductionThe Casmo molybdenite deposit is 6 km southwest of the asbestos mining town of Cassiar in northern British Columbia, at an elevation of 1,550 metres. Molybdenite was first discovered during the early 1950s and the first important exploration work was done in 1964. Between 1964 and 1971, about 25,000 feet of drilling was done by various operators, as a result of which 33.7 million tons of molybdenite ore was drill indicated at a grade of 0.123%. In 1979, Shell Canada Resources entered into an option agreement with the former operator, New Jersey Zinc Corporation. Shell completed 27,000 feet of diamond drilling between 1979 and 1980 and ha s reported 75 million tonnes of drill-indicated ore with an average grade of 0.13% MoS2• This paper is a case history of IP I resistivity and magnetometer surveys done over the Casmo deposit during 1979 and 1980."

Jan 1, 1983

By John Chipman, Daniel Dutilloy

The equilibrium of gaseolis H2O-H2 mixtures with liquid iron-phosphorus alloys in the range 0 to 3 pct P is used to establish the increuse of the activity coefficient of oxygen, in the presence of phosphorus. Two different sampling techniques are used. THE importance of oxygen as a refining agent in steelmaking operations makes it desirable to improve our understanding of its behavior. Phosphorus which is always present in the ores has adverse effects on steel properties and its removal is necessary. The present study was undertaken to evaluate the interaction of oxygen and phosphorus in molten iron. Bookey, Richardson, and welch1 have studied the phosphorus-oxygen equilibria in liquid iron in the presence of lime. They used a mixture of hydrogen and water vapor to control the oxygen potential and worked with crucibles made of tetracalcium phosphate and lime. At low phosphorus concentration, i.e., at high oxygen, they observed a marked deviation in their results. They tentatively ascribed this to a large negative effect of oxygen on the activity of phosphorus. This was then included by chipman2 in his review of interactions in liquid iron. Pearson and Turkdogan 3 have later reported an interaction parameter They equilibrated a mixture of hydrogen and water vapor with an iron-phosphorus alloy contained in an alumina crucible and sampled the melt by suction in a silica tube. The solubility of oxygen in iron-phosphorus alloys has been studied by Levenets and Samarin.4 They reported an interaction parameter

Jan 1, 1961

By Purushottam Kumar

Keywords: Magnetostriction, magnetic properties, Pd(Fe,Co,Ni) single crystals Fe-Pd, Co-Pd and Ni-Pd alloy systems show appreciable magnetostrictive strains that are of interest for sensor applications. These systems exhibit congruent melting minima. In this work the magnetic and magnetostrictive behavior of congruent melting Fe-Pd, Co-Pd, and Ni-Pd compositions have been examined. The alloys examined include Fe-54.9 at.-% Pd, Ni-45.4 at.-% Pd, and Co-45 at.-% Pd. The paper describes the growth of bulk single crystals of these alloys using Czochralski technique. X-ray diffractometer was used to obtain rocking curves that were used to determine the [001] crystal direction. Magnetostriction in [001] direction was measured using strain gages. Magnetic properties were measured using a vibrating sample magnetometer. Ni-Pd showed the highest magnetostriction values among the congruent melting compositions. Magnetic and magnetostrictive behaviors of these alloy single crystals are presented.

Jan 1, 2005

By C. D. Broadbent

INTRODUCTION The slope stability research plan at Kennecott was developed to serve the specific needs of large, open pit mines; primarily those developed in faulted and highly-fractured intrusive deposits. The program emphasis is on applied research; being defined in this case as research into the engineering mechanics of discontinuous rock and into the related rock property survey and slope design techniques. The program has been developed in phases, with each phase organized to explore more thoroughly the most significant findings of previous work and to improve on techniques found to be applicable. The current work is based on principles developed early in the program and that show promise of having engineering and economic value. A brief summary of the conceptual principles of the program is given to put our current work in context. This is followed by a review of the two cooperative programs done with the U. S. Bureau of Mines. Most recent work is described and interpreted in terms of practical slope design. Although failure-free slopes are a desirable goal, it is recognized that some failures will occur when overall slope designs approach a calculated safety factor of one. A discussion of failure control research is therefore offered. BACKGROUND In 1965 Kennecott management specified that a slope stability technology must be used to achieve optimum development of ore resources. The subject was carefully explored and by 1960 it had been established that there was no technology readily applicable to open pit slope design. Therefore, in 1962, Kennecott Copper Corporation and the U. S. Bureau of Mines agreed upon a cooperative research program having the objective of developing a mine slope stability science. One of the first decisions made by the cooperating groups was that the research must be conducted primarily in the field and not in the unrealistic environments of a laboratory. Accordingly, the Kimbley Pit, an abandoned mine once operated by Kennecott's Nevada Mines Division in Nevada, was selected for the full-scale research. Fortunately, there was near-universal agreement on the basic stability parameters and thus on the areas to be investigated. These parameters were acknowledged to be: (1) anisotropy (generally due to faults or joints), (2) stress, and (3) water; in that order of importance.

Jan 1, 1972