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By D. M. Podobnik, J. F. Shirley

The Cuajone Concentrator of the Southern Peru Copper Corp. is located approximately 900 km southeast of Lima, Peru, near the 500 year old town of Moquegua, in an area that has been occupied since antiquity since the plant was started in July, 1976, the throughput has steadily increased from 36 to 46 kt/d (50,7055tpd). The widely distributed molybdenite content of the ore body ranges from 0.02-0.4% MoS2. The molybdenite content of the copper concentrate has always been sufficient to justify operation of a byproduct molybdenite plant. During the first nine months of 1980, the average grade of the ore was 1.169% copper and 0.026% molybdenite. Pilot plant testing conducted during 1970 at Toquepala, Cuajone's sister plant, determined that the recovery of the molybdenite into a salable concentrate could be accomplished relatively easily by using the Asmol process. Experience gained at Toquepala, which converted to Asmol in 1969, confirmed the simplicity of process. Simplicity of operation was one of the major criteria for the process selection because, at the time, it was expected that the molybdenite plant would start up concurrently with the copper concentrator. Other processes studied either produced inferior results or were judged more difficult to operate. However, geological information indicated that the molybdenite content of the ore would be relatively low for the first couple of years of operation, so the design and construction of the plant was delayed until after the copper plant was in production. Asmol remained the process selection. During 1976 and 1977, the flowsheet and plant layout based on pilot plant data, new results obtained from Cuajone's metallurgical laboratory, and process improvements from Toquepala's experience were completed. One of the more important innovations from the Cuajone laboratory was that the Asmol consumption could be substantially reduced by replacing air with nitrogen gas in the rougher and first cleaner flotation steps

Jan 1, 1983

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Jan 1, 1949

By W. B. Clarke

It is the purpose of this paper to discuss briefly some of the recent developmellts in connection with the use of electrical apparatus for the mining of coal. For several years electricity has been employed extensively for the distribution of power, primarily for the operation of mine-locomotives and chain coal-cutters, and secondarily for motors driving pumps, ventilating-fans, rope-haulage, conveyors, crushers, auger-drills, coke-oven larries, etc. The severe and peculiar conditions which attend the development and distribution of power for the operation of coalmining machinery constitute a field to which the electricmotor seems to be especially adapted. The underground use of steam-engines, to any great extent, is impracticable for obvious reasons. The much higher efficiency of the electrical system is a potent argument in its favor as compared with compressed air, which, under ordinary circumstances, should only be employed for the operation of rock-drills and coal" punchers." The conditions in many mines prohibit the under-cutting of coal with a chain-machine; and the compressed-air " puncher," with its very low efficiency, is extensively employed. There have been no recent important improvements in the design and construction of the chain-machine, although, of course, minor changes are continually being made. More time and attention are being paid now than ever before to the details of mining-machinery, with the idea of eliminating the weaknesses which have been developed, and especially of facilitating repairs and renewals. Electric mine-locomotives are very extensively employecl for the haulage of coal on the main entries and the branchheadings; but in the majority of coal-mines the cars are still

Jan 1, 1904

By C. W. Baxter

Eveleth Taconite Co. was formed in 1963 to mine and beneficiate taconite on the Mesabi Range. Its Thunderbird mine is located mid-way between the cities of Eveleth and Virginia, Minn. The program for blasting restraints here is unique not only on the Mesabi Range but possibly in the world. The ore is a hard siliceous taconite. Its structure varies from bedded to massive with prominent vertical jointing. The jointing of the top or outcrop of the orebody is a challenge for the blasting practices as it is the source of an estimated 75% of the secondary breakage.

Jan 11, 1972

By L. W. Pommier, F. B. Brien

The Rheological properties of pulps are non-Newtonian in character and more than one viscosity parameter is necessary to describe their behavior, therefore, the single term 'apparent viscosity' which has been used in the past may be misleading. The study reported in this paper uses a dimensional analysis based on the Ostwald-de Waele shear stress-rate of shear model for non-Newtonian liquids to develop velocity and resistance equations for falling spheres. An electronic monitoring apparatus was assembled for determining the velocity of metallic bodies as they fall through opaque liquids and suspensions. By means of this apparatus the behavior of the viscosity parameters of the Ostwald-de Waele model and the applicability of the proposed equations were examined for a number of non-Newtonian liquids. The validity of the equations for these liquids was confirmed. Preliminary data collected using solid-liquid suspensions established the validity of the form of the basic equations for these systems. The differential movement of solid particles through solid-liquid pulps and suspensions is very important LO many branches of engineering, such as minerals processing, soil mechanics, ceramic slip processing, oil well drilling-mud technology, materials-handling in pipelines, and many others. There is a dearth of fundamental knowledge on the flow resistance encountered by immersed bodies moving through solid-liquid suspensions. The resistance offered by Newtonian liquids to the movement of free settling spheres is well described for laminar and turbulent conditions by Stokes' and Newton's Laws, respectively. However, problems are encountered when attempts are made to extrapolate these simple relationships into solid liquid suspensions. The rheological properties of pulps are such that they are non-Newtonian in character;'" that is, the applied shearing stress and resulting rate-of-shear are related by non-linear functions, and thus, in the simplest case two viscosity parameters are necessary to describe their rheological properties. For this reason the single term 'apparent viscosity' which has been commonly used to explain the flow resistance of suspensions and non-Newtonian liquids may be misleading. It is realized that a rigorous analysis of the rnechanisms of momentum transport of liquid-solid systems is complex indeed. There are many variables that affect the rheological properties of the systems such as density, size, shape, and surface energy of the suspended solid and density and viscosity of suspending liquid, as well as the solid to liquid ratio. However, it was felt that a useful contribution to the knowledge of the behavior of suspensions could be made by examining the systems in terms of the basic fundamentals of nowNewtonian flow. This has led to the development, by means of dimensional analysis, of velocity and resistance equations, using two viscosity parameters to describe the velocity of penetrating bodies and the flow resistance encountered by these bodies, as they pass through non-Newtonian systems. THEORY In order to examine the effects of the rheological properties of solid-liquid suspensions on the movement of immersed bodies it is appropriate to start with non-Newtonian liquids and develop equations, analogous to those of Stokes and Newton, for laminar and turbulent flow respectively, from which quantitative information may be obtained. Further investigation would then be directed at the complex suspension systems, and the effects of the many variables on the velocity and resistance equations. Liquids are classified on a basis of viscosity which may be defined as the relationship between applied shear stress and resulting rate of shear?-'* Pure single phase liquids composed of small light molecules behave as Newtonian liquids, having a single viscosity parameter since the shearing stress and rate-of-shear are related by a linear function. Bingham plastics are similar but have a yield stress. Of particular importance in our investigation are dilatant (shear thickening) and pseudoplastic (shear thinning) non-Newtonian liquids, with and without yield values.

Jan 1, 1968

By B. J. Kochanowsky

To improve blasting methods it is necessary to know how the explosive force acts and how rock resists this force. Because of the tremendous power developed within milliseconds and the great number of other factors directly affecting the technical and economic results, an analysis of the fundamentals of blasting theory is difficult. But since the rules used for layout design and for calculations of size of explosive charges are based on theoretical assumptions, complete knowledge of blasting theory has great practical importance in mining. Analysis of Blasting Theory: It is interesting to note the opinion of blasting experts with respect to contemporary blasting theories. F. Stussi,' Professor of the University of Zurich, stated: "We do not have enough experience yet to change our army engineering regulations in blasting and base it on new fundamentals. It is our duty to collect more practical data and to do more research in blasting to close this gap." K. H. Fraenkel,' editor of the Manual on Rock Blasting published in 1953 in Sweden and written by well-known Swedish, German, Swiss, and French blasting and explosive experts, said: "To the best of our knowledge no suitable formulas for civil blasting work are to be found in the American, French or German literature."

Sep 1, 1955

By Max Barber

PRESENT equipment and practices in open-pit mines of the Lake Superior iron ranges have been described recently in some detail by A. H. Hubbell.1 It is anticipated that any further improvements will be the result of gradual evolution of present methods and equipment, just as those now used have been gradually evolved from earlier methods. An exception to the process of gradual evolution during the last decade has been the adoption of electric power for operating shovels and trains in open-pit mines, but it is not expected that any such revolutionary changes will be made in the future. The use of Diesel, engine equipment will gain considerable headway, no doubt, and will find favor in certain lines of operation as improvements and adaptations are evolved to meet particular requirements. The question of installing belt conveyors for handling material from deep mines of restricted area, where haulage grades become a serious consideration, or even for transferring earth, rock, or ore material for distances of several miles, is now being studied and some very interesting data are being obtained.

Jan 1, 1932

By C. S. Witherell

THE first feature that strikes one when considering the use of air enriched with oxygen in pyrochemical processes is the conservation of Enriched Air FIG. 1.-TEMPERATURES THEORETICALLY OBTAINABLE BY BURNING PURE AMOR¬PHOUS CARBON IN AN ATMOSPHERE COMPOSED OF AIR ENRICHED WITH OXYGEN, PRODUCING GAS CONTAINING CO. heat due to the partial elimination of the inert heat-carrier nitrogen, as set forth in the report of the committee. The second feature, which

Jan 11, 1924

By E. B. Fitch

The operating behavior of liquid-solid cyclones is outlined, together with the nature and range of the process results obtainable, to serve as a background for engineers wishing to consider application of this new process tool.

Jan 3, 1953

By Donald C. Moore

INTRODUCTION Published laboratory procedures used by the major crusher manufacturers for estimating crusher size are based upon techniques developed in the mid 1940's. Specifically, the two largest U.S. crusher manufacturers are using the Bond impact procedure. Although the procedure is still in use, there is little confidence in the results. Unless the laboratory results fall within a preconceived range, personal experience is used for selecting the number of crushers and connected horsepower (Coleman, 1978). There have been numerous theoretical studies of the communition of particles. However, no procedure has been widely acclaimed for predicting crusher power requirements. Experimental studies have included breakage by slow compression, slow speed impact and high speed impact. Theoretical results have increased our knowledge of the comminution process, but the procedures have not been capable of analyzing the complex mechanism of industrial crushing machines. The purpose of this chapter is to review the empirical crushing procedures that have been used, including advantages and disadvantages. A new procedure which has been in development at Allis-Chalmers Corp. from 1977 to 1982 is detailed. Actual results of the new procedure on a concentrator feasibility study are included. EXPERIMENTAL GOALS The goals of a laboratory crushability procedure are accurate predictions of: (1) Rock crushability, measured as energy per unit mass. (2) Crusher product size analysis. A procedure capable of predicting these parameters should be inexpensive and require a minimum amount of sample. CRUSHABILITY TESTS Bond Impact Procedure F. C. Bond (1946) detailed the development of the pendulum impact device that is still used by the leading crusher manufacturers (Bond; Rexnord, 1976). The device (Fig. 1) is comprised of two bicycle wheels with 13.6 kg steel hammers tangentially attached to the rims. The hammer faces are 50 mm apart at rest. On opposite ends of the hammers lifting

Jan 1, 1982

By Subhash C. Malhotra

This paper discusses the historical background on major sources of obsolete electronic scrap and spent catalytic converter scrap. The paper discusses the principal changes taking place that will affect the future supply of these scraps. The author projects from this background the future opportunities for reclaimers and refiners in these two important segments of the precious metals scrap reclamation industry.

Jan 1, 1984

By P. E. Fitzgerald, Dana G. Hefley

An apparatus has been developed which permits selective acidizing of producing formations and determination of the relative permeability of a formation by fluid injection. This apparatus, known as the "Electric Pilot," is an electrical fluid-interface locator, the electrical circuit of which is completed when the elec-tcodes in the well are in contact with a conductive fluid, but is not completed when immersed in a nonconductive fluid. Results are given for a number of typical acidizing applications in which the interface locator was used to control the acid. Description of the method used in making a permeability survey and the data obtained are also included. Introduction Early in the development of the acidizing industry it was recognized that one of the most important problems to be solved in the chemical treatment of any well was the determination of what part of the exposed section in the well should be treated and the selection of the technique that would insure treatment of the desired section. One of the first techniques adopted for assisting in proper placement of the acid, which is still widely used, is the method of confining the acid to the producing section by means of a column of oil, which is known as the Carr1 method of treatment, named for its inventor. In the Carr method it is not possible to selectively acidize a specific horizon in a multiple pay zone, so many improvements and modifications of the basic Carr technique were devised to accomplish this result. In order to overcome the possibility of the acid entering an undesirable section at the bottom of the well, organic gel plugs2 were introduced into the bottom of the well, which served to halt the entrance of the treating solution into these zones.3 These chemical gels later liquefied because of bacterial action and were removed from the well with the produced fluid. In fields where a gas cap existed, as in the Goldsmith field of Ector County, Texas) it was imperative that a treating technique be evolved that would confine the acid to the oil-producing zone below the gas cap. By so doing the oil-productive capacity of the wells could be improved without greatly increasing the gas production and this would lower the gas-oil ratio of the well. ~h, technique employed4 to achieve this effect utilized two pumps, one for pumping the chemicals down the tubing, the other to simultaneously force oil down the annular space to confine the acid to the oil pay, thus preventing the chemicals from entering the upper gas-bearing zones. Experience has indicated that gas wells and certain types of oil wells respond better to ''stage treating.'' This technique utilizes the introduction of a certain volume of acid and then allows the well to ''clean up99 before introduction of the next and usually successively larger stages. Where such methods are employed steps must be taken to keep a disproportionate share of the acid from entering the most permeable and previously treated Zones. A special tool

Jan 1, 1944

By P. E. Fitzgerald, Dana G. Hefley

An apparatus has been developed which permits selective acidizing of producing formations and determination of the relative permeability of a formation by fluid injection. This apparatus, known as the "Electric Pilot," is an electrical fluid-interface locator, the electrical circuit of which is completed when the elec-tcodes in the well are in contact with a conductive fluid, but is not completed when immersed in a nonconductive fluid. Results are given for a number of typical acidizing applications in which the interface locator was used to control the acid. Description of the method used in making a permeability survey and the data obtained are also included. Introduction Early in the development of the acidizing industry it was recognized that one of the most important problems to be solved in the chemical treatment of any well was the determination of what part of the exposed section in the well should be treated and the selection of the technique that would insure treatment of the desired section. One of the first techniques adopted for assisting in proper placement of the acid, which is still widely used, is the method of confining the acid to the producing section by means of a column of oil, which is known as the Carr1 method of treatment, named for its inventor. In the Carr method it is not possible to selectively acidize a specific horizon in a multiple pay zone, so many improvements and modifications of the basic Carr technique were devised to accomplish this result. In order to overcome the possibility of the acid entering an undesirable section at the bottom of the well, organic gel plugs2 were introduced into the bottom of the well, which served to halt the entrance of the treating solution into these zones.3 These chemical gels later liquefied because of bacterial action and were removed from the well with the produced fluid. In fields where a gas cap existed, as in the Goldsmith field of Ector County, Texas) it was imperative that a treating technique be evolved that would confine the acid to the oil-producing zone below the gas cap. By so doing the oil-productive capacity of the wells could be improved without greatly increasing the gas production and this would lower the gas-oil ratio of the well. ~h, technique employed4 to achieve this effect utilized two pumps, one for pumping the chemicals down the tubing, the other to simultaneously force oil down the annular space to confine the acid to the oil pay, thus preventing the chemicals from entering the upper gas-bearing zones. Experience has indicated that gas wells and certain types of oil wells respond better to ''stage treating.'' This technique utilizes the introduction of a certain volume of acid and then allows the well to ''clean up99 before introduction of the next and usually successively larger stages. Where such methods are employed steps must be taken to keep a disproportionate share of the acid from entering the most permeable and previously treated Zones. A special tool

Jan 1, 1944

Jan 1, 1943

By Gary B. Williamson, Barton K. Cross

Digital simulation is a modern analysis tool which allows the mine operator to evaluate the result of making a decision without actually changing the organization or buying the equipment. The purpose of this paper is to demonstrate the use of digital simulation in evaluating a decision of whether or not to introduce dispatching in an open pit mine. The analysis shows that appreciable savings can be realized by dispatching. In certain cases, an operator can reduce the number of trucks required to move a specified tonnage. A second analysis evaluates the alternatives of using one large shovel or two smaller units. In this case, the operating cost of the haulage equipment necessary to support the shovels turns out to be the critical factor in this decision.

Jan 1, 1969

By N. Rowlands, J. A. Finch, R. Espinosa-Gomez

The sulphation roast-leach process for complex sulphides results in phase changes due to roasting and leaching. The phases in the calcine, and in the neutral and hot acid leach residues were identified and their degree of liberation determined in order to design and Interpret separation tests on the residues. The hot acid leach residue was composed of hematite, silica, and lead sulphate with some associated silver. Magnetic separation was selected as the process for producing a lead concentrate, as the non-magnetic product. Separation was limited by -1 pm hematite reporting to the product, and hematite/lead sulphate agglomerates reporting to the magnetics.

Jan 1, 1984