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By T. I. Probert, B. W. Burdett, L. B. Hales

Selecting a mineral processing control system from the multitude of offerings can be a formidable task. To assist the plant designer, the material in this chapter includes the advantages and disadvantages of different equipment types, configurations, and control strategies. Selection procedures are detailed, and the importance of each step in the design and selection process is explained.

Jan 1, 1986

By J. Walter Snavely

PRESENT-DAY processing in many industries, calcining, sintering, briquetting, beneficiation and nodulizing, increasingly calls for the handling of large volumes of hot bulk materials. Various types of conveyors have been employed. This discussion will cover the factors governing their selection. For temperature ranges up to 400°F, or approximately 200°C, a wide range of conveyors is available. Special constructions of rubber conveyor belts. steel conveyor belts, vibrating and shaker conveyors, apron conveyors, and drag chain conveyors, all are used successfully. As temperatures go well above 400°F, however, choice of conveyors is narrowly limited. This paper will consider the problem of handling bulk materials only where the temperatures exceed 400°F.

Jan 5, 1953

By N. Aslin, R. Clark, G. Heferen

The methods of harvesting copper from stainless steel mother plates has been investigated from fundamental and operational experience perspectives. At least five different harvesting techniques have been identified that have different effects on product quality, current efficiency, current distribution, growth morphology and ease of stripping. Each method is examined from fundamental principles to understand what occurs during the harvesting process and why the particular effects are manifested. Experience from plants operating the harvesting method is provided to show that the fundamental understanding is relevant. Best practice harvesting method and harvesting management are described.

Jan 1, 2014

By G. J. Dickman, W. N. Thomas

The factors involved in selecting, a drive system for a grinding mill, including gearing arrangement, motor selection, and electric-supply system limitations are reviewed. Equipment costs are evaluated on a dollar per horsepower basis and starting performance is analyzed, the latter making use of a recently developed computer program. The present interest in large-diameter grinding mills and the rapidly rising cost of the drive in proportion to the cost of the mill establishes a need to explore the drive system in detail. The drive for a 7 to 8,000 hp mill will cost from $350 to $600,000 which represents nearly half the total cost of the mill package, and requires as much building space as the mill proper. Some of the drive components require a longer time to manufacture and the installation time and costs are equal to those for the mill. It is apparent that the drive has become a dominant factor in the overall mill design consideration. A new plant requires a tremendous investment in both time and money. With the high degree of competition in the mining industry, low capital cost is an exceedingly important factor in the development of a project. It is just as important, however, to insure that the equipment is going to perform satisfactorily for the anticipated life of the project without adding unplanned operating, maintenance, and replacement costs. This is the position in which the engineer or designer usually finds himself and is really one of his primary functionsestablishing a realistic compromise between cost and performance. Large primary grinding mills can represent a major portion of the cost of a plant and the drive system accounts for a substantial part of this cost. These facts justify a careful analysis of the drive requirements and all of the factors involved in ultimately arriving at the best system for the lowest cost. A number of excellent papers have been published on various aspects of mill drives. The authors have used information from these papers in making a study of a drive for a 7600-hp, 32 x 12-ft autogenous mill. This was a broad investigation, including mechanical and electrical design, layout, performance, and maintenance considerations, and overall economics leading to the selection of the optimum system for that mill. This paper was developed from the study and includes information applicable to large mills in general. For a successful and economical application, the drive must be considered as a system and all of the components analyzed to determine their effect on the system. This requires the participation of the mill designer, gear, and other mechanical component manufacturers, motor manufacturer, plant designer, and operator. A careful analysis of the mill torque requirements is first necessary to provide a basis for selection of the mechanical and electrical drive components. Because of manufacturing limitations on the size and capacity of gearing available for these low-speed applications, an evaluation of costs for various gear ratios and configurations in conjunction with motor speeds is required. Consultation with the power-supply company is necessary to determine limitations on motor-starting disturbances and to analyze operating costs on the basis of existing rate structures and low characteristics. Finally, consideration must be given to the drive arrangement and its affect on plant layout, space requirements, and location of auxiliary equipment for the selected process. There are presently three basic schemes for driving a mill. The first is a direct drive by a motor operating at mill speed with no gearing. The second is by a higher-speed motor through a trunnion-connected gear drive. The third is by a motor through the more conventional pinion and ring-gear with the option of an interposing gear box to permit greater motor speed than pinion shaft speed. [(Fig. 1.)] Several manufacturers have or are presently developing motors which drive the mill directly without the use of gears. One arrangement has the motor armature intimately surrounding the mill shell-discharge spout or extension of the trunnion journal. The motor stator is then supported independently and surrounds the shell or trunnion-mounted rotor. Another variation utilizes an independent mill-speed motor connected to the trunnion by a drive shaft and flexible couplings.

Jan 1, 1972

By C. R. Euston, B. T. Field, W. E. Lindquist

Pyroprocessing applications in the minerals industry range from low-temperature drying to high-temperature reactions. Material characteristics and process requirements range over a very broad spectrum and can confuse plant engineers trying to select a pyroprocessirtg system for their plant. This paper examines the important process variables and offers empirical guidelines to assist in a user's overall process evaluation.

Jan 1, 2000

By L Gill

The four basic types of electric motors -squirrel-cage, wound rotor, synchronous and D.C. -are de-scribed, with particular reference to speed-torque characteristics. The three classifications of squirrel-cage motors, C.E.M.A. B, C and D, are compared, and methods of selection for specific drives are outlined. Wound rotor and synchronous motors are covered from the viewpoint of construction details, methods of operation and control required. The application of these motors to crushers, conveyors and ball mills is described and reasons for their selection are given. The application of D.C. motors to haulage equipment and mine hoist drives is included, and the basic principles of a variable voltage drive are illustrated. Efforts have been made through-out to provide specific examples of motor selection, with particular reference to the mining industry. THIS paper will attempt to answer the question -"which motor should be used for a specific drive?" Although it is impossible to cover the complete subject of electric motor application here, we hope to give some idea of the types of motors available and why certain types are used on specific applications.

Jan 1, 1963

By J. H. McKibbon

This paper outlines the basic steps in the sizing of electrostatic precipitators according to the Deutsch equation. Design parameters that do not appear in the equation are also described.

Jan 1, 1971

By K Dudley, D Readett

The design of entrainment control processes in copper SX plants has been studied by use of models based on achievable plant performance. A number of alternatives have been assessed for their suitability in minimising the transfer of deleterious species from PLS into the electrolyte. The position of the wash (scrub) stage in the circuit, either before or after the loaded organic tank, has been the subject of considerable debate. The modelling shows that at ænormalÆ entrainment levels, the performance of the circuits are very similar. However at high entrainment levels the selection of the wash after the loaded organic storage has significantly lower transfer of contaminants. When considering the inclusion of a loaded organic coalescer the results of the modelling again show that the best circuit has the loaded organic storage/coalescer before the wash stage. The overall control of EW contaminants includes both a wash stage and an EW bleed flow. The total water use for these two flows is shown to go through an absolute minimum. The minimum flow rate is not greatly dependant on the total entrainment from the SX settlers. This can be a useful operating strategy if the quantity of high quality water for make up is limited by the capacity of the water treatment plant (eg RO). However the minimum cost option is to maximise the flow of water to the wash stage and minimise the EW bleed stream. The main driver for this is the cost of the cobalt sulphate contained in the electrolyte. Some results from the latest circuit modifications at the Nifty and Girilambone Copper Projects are presented to confirm the benefits of using both coalescing systems and a wash stage. The EW bleed has been reduced to a level that is less than the loss internally in the SX stage to stage entrainment. There has been an occasional need to add chloride to the EW to maintain sufficient concentration to act as a growth modifier.

Jan 1, 2002

By E Rojas, C Pardo

The exploitation of primary ores using cave mining caused new challenges at the El Teniente mine that required changes to a number of conventional cave mining practices. For example, in the 1970s and 1980s, panel caving was introduced to manage certain geotechnical and operational conditions. Today, El Teniente mine is facing new challenges associated with deep cave mining and establishing its New Mine Level (NML) project, which is located 240 m below the Esmeralda operating cave.The engineering and development phases for this new project have been largely based on experience and lessons learned throughout the history of primary ore exploitation at El Teniente mine, particularly knowledge about seismicity control, the management of collapses and operational practices. For example, previous experience demonstrated that seismicity could be managed by preconditioning using large-scale hydraulic fracturing (HF). HF has been systematically applied in the column of ore above the undercut planned for the NML project and below the production or extraction level, where the main ventilation and haulage infrastructure are to be located.This paper discusses how this has been achieved and is based on previous experience of preconditioning using HF, which has been applied in the selection and management of exploitation techniques and associated planning strategies and design parameters for the NML project.CITATION:Pardo, C and Rojas, E, 2016. Selection of exploitation method based on the experience of hydraulic fracture techniques at the El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 97–104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Mustafa Onder

The paper point out that there are two méthods in the design of the long auxiliary ventilation systems. These methods can be summarized as constant fan spacing and constant fan size. If the fans are placed at the end of the duct, leakage will increase due to the high combined pressure.Also The program called SERIP can be used to examine the effects of positioning the fans at varying distances along the duct and determine the appropriate locations.

Jul 17, 2000

By Wm. D. Jr. Sheldon

THIS paper presents practical data to aid in the selection of a mine ventilating fan, and outlines considerations to be made to ensure satisfactory operation and optimum efficiency of the fan. Much has been published on the general subject of mine ventilation, but the writer has found few specific data on factors and considerations which govern the selection of a fan-data which should be available to the operator if his fan is to give satisfactory service within the range of the high-efficiency portion of its performance curve and deliver the specified air capacity when operating against the anticipated range of resistance of the mine. The total quantity of fresh air furnished by the ventilation system must be adequate to provide, and to ensure at all times, safe and healthful working conditions in the mine. It is assumed that the mine operator is able to determine the air quantities required for the various parts of the mine.

Jan 1, 1941

By Mahesh C. Jha, Frank J. Smit

Column flotation and selective agglomeration are promising advanced physical cleaning processes that can be developed for preparing premium quality coal-water slurry fuel from coal fines. Such a fuel could either replace oil or natural gas in certain industrial and utility boilers or else could be burned in advanced combustors currently under development. These applications require coal cleaned to sulfur and ash contents below 258 g/GJ and 430 - 860 g/GJ (0.6 lb/million Btu and 1 - 2 lb/million Btu), respectively, to meet clean air emission requirements. A highly loaded slurry must be produced in order to avoid derating the boilers, and the total cost of the fuel must be below $2.37/GJ ($2.50/million Btu) in order to penetrate the market by the turn of the century. Achieving these technical and economic goals depend critically on the selection of suitable feed coals. This paper describes the identification and evaluation of 18 coals and final selection of six coals from different regions of the United States as potential feedstock for preparation of premium fuel. The work is being performed under a cost-shared DOE project.

Jan 1, 1995

By Daniel Hodouin, Claude Bazin

"This paper examines the economic advantages of adapting the production grade and recovery targets of a flotation circuit as a function of metal prices. The study is periormed using a steady state simulator for a Cu-Zn differential flotation circuit operating under the following strategies of 1) Maintaining constant operating targets, 2) Maximizing individual circuit Net Smelter Return and 3) Maximizing the global Cu-Zn circuit efficiency. Results are compared to assess whether or not one of the strategies produces benefits significantly higher than the others. A discussion of the tools required to achieve such a kind of control completes the paper.Paper not Available at Time of Publication"

Jan 1, 1997

The degree of ionicity-covalency of complex compounds is discussed here as a prospective criterion for selection and purposeful synthesis of sulfhydril and oxhydril collectors. Theoretical predictions of flotation behaviour were confirmed by flotation of a number of ores.

Jan 1, 2005

By R. O. Burt

Gravity concentration - the separation of minerals according to their relative density - is one of the oldest forms of mineral processing. Even though modern technology has developed a range of other processes, gravity concentration remains as one of the most important methods employed for mineral separation. The range of minerals recovered covers a wide spectrum, from andelusite to zircon, from coal to diamond, from gold to industrial mineral. The long history of gravity concen¬tration, along with a still imperfect understanding of the various mechanisms involved has resulted in a series of ingenious engineers developing, some¬times perfecting and sometimes rejecting, a wide range of equipment, suited for a variety of different duties. 'Selection' in the context of gravity separation, is primarily the choice of the right type of equipment for the separation in hand; 'sizing' of the correctly chosen unit is, more often than not, determining the appropriate number of units required to suit the throughput. The accent of this chapter will, therefore be 'selection'. A brief description of the major types of gravity concentration equipment will follow a discussion of the factors which determine the selection of the correct unit. CLASSIFICATION OF GRAVITY CONCENTRATION EQUIPMENT All concentration equipment has a primary function and a secondary function. The primary function is the efficient separation of the constituent minerals into two or more discrete phases; the secondary function is to effectively cause the discharge of these discrete phases into separate compartments (Aplan 1975). For maximum efficiency of operation, the forces which effect the primary function should not also result in the secondary function occurring; in such cases optimum operating conditions required for the primary function, separation, may have to be compromised to ensure reasonably efficient operation of the secondary function, product discharge. With gravity concentration, the primary function is effected by the relative movement of minerals of different density in response to gravity and one or more other forces, the latter often including the

Jan 1, 1986

By Ho-Seok Jeon

The separation in gravity concentrators is based on the density difference between valuable and gangue minerals. In addition to density, many auxiliary parameters like particle size, shape, feed rate, pulp density etc. plays an important role in the separation. The performance efficiency of gravity units is largely based on the interference of such auxiliary parameters during separation. Many gravity concentrators are used for the beneficiation of cassiterite ores and performance of which are varying with different feed material, particle size and required enrichment from the unit. Selection of gravity units is generally based on laboratory testing and data collected from the previous experience. In the present investigation cassiterite ore collected from Uljin deposit, South Korea has been subjected to various gravity units like jig, spiral, and Knelson concentrator with the intension to pre-concentrate the ore. Second stage concentration was carried out using shaking tables. The article mainly summarizes performance evaluation methods employed for gravity concentrators. Selection of gravity circuit for the beneficiation of cassiterite was made on the basis of the recovery-grade curve, and Tromp curve methods. Keywords: cassiterite, gravity concentration, recovery-grade curve, sink-float test, tromp curve

Sep 1, 2012

By Howard S. Avery

The wear resistance of an alloy in heavy mill liner sections may be quite different from that of the same alloy in small balls and other light sections. This fact was established by means of a well standardized laboratory test that was validated for ball mill service. The salient properties of mill liner alloys, including austenitic manganese steels, medium alloy hardenable steels, and abrasion resistance cast irons are described, critically compared, and quantitatively ranked in terms of mill liner service. Where they are tough enough the high-chromium and other martensitic cast irons (e.g. Ni-Hard) promise maximum economy, but their section sensitivity is a limitation. To overcome this an extensive research program studied over a hundred experimental alloys, ranking them for heavy section abrasion resistance by means of the laboratory test. Computer analysis of the results provided a parabolic formula in terms of composition, the apexes of the parabolas providing optimum wear resistance. From the extensive family of parabolas one apex was selected for intensive study in experimental liners, pilot plant production, development of quality controls, and finally full scale production. This is a 19% chromium iron critically alloyed with nickel and molybdenum and hardened by heat treatment. It has excellent resistance to various types of abrasion, but its chief advantage is in heavy mill liner sections, where it has about 25% better abrasion resistance than the best of the quality controlled chilled Ni-Hards. It is also tougher. After production problems were solved, a number of ball and rod mill tests were arranged on a guaranteed performance basis. Two of these, representing about 138,000 pounds of mill liner castings, have recently confirmed in service the superiority that was predicted by the laboratory tests.

Jan 1, 1969

By A. K. Ghose

The increasing application of roadheading machines in the coal industry has prompted the development of an appropriate selection methodology for such machine applications in specific locales. Accurate geological sections and comprehensive rock testing are required for all machine tunneling. Using suitable geotechnical parameters and index tests, sensitive both to excavability and standability of the strata, a classification scheme has evolved to help evaluate the rock mass vis-a-vis application of a given weight-class of roadheading machine. The classification parameters include point load index, brittleness, abrasiveness, average crack density, and ground water, which with assigned numerical ratings, lead to a quantitative global rating of the rock mass. For each rock mass class, the selection of an appropriate roadheading machine is recommended. The paper illustrates the application of the rock mass rating system and also describes simple index tests for evaluating the classification parameters for brittleness and abrasiveness. Manuscript not received in time for publication.

Jan 1, 1983

By M K. Singh

Mining is nothing but an art - besides being a science - of extracting valuable minerals from the womb of the mother earth. In this gigantic task, a large number of machinery and equipment are employed judiciously. Wire ropes play a vital role in lifting or hoisting men and materials under hostile/adverse working conditions and constitute a major item of investment on machinery/equipment. The economy of using a wire rope is a concern for engineers, users and the planners. The economic use of wire ropes for mining purposes largely depends on the following factors;Mechanical design considerations - which include tensile strength of wires, elasticity, resistance to abrasion and crushing, fatigue values, static and dynamic loads on wire ropes, factor of safety, fleet angle, etc. Metallurgical consideration - Composition and heat treatment of wire materials, defects like inclusions and voids, surface quality factor, lubrications, micro structural parameters. Operational consideration - Seizing and cutting of rope, storage, care and maintenance, cutting back, etc. Environmental consideration - Temperature and humidity, pit condition, dust, corrosive atmosphere, etc. In the present paper, an attempt will be made to suggest steps for achieving optimum economy while using the wire ropes for extraction of precious minerals and coal keeping in view the points noted earlier. Once technical viability is established, economy is the ultimate consideration for an industry for safe hoisting of men and material.

Jan 1, 2000

By Ronald G. Hamm

"With the advent in Canada of large open-pit equipment, the associated wire rope required must keep pace, especially in design and construction, along with the field that leads to increased rope life.This paper will first describe the various types of shovels and draglines in use today and also the unique characteristics of the wire rope required to efficiently service this equipment.Emphasis will be placed on the special equipment and techniques required in the wire rope manufacturing, along with the maintenance procedures required for a profitable operation.IntroductionOpen-pit and strip mining is increasingly playing an important role in the Canadian mining industry.An integral part of the surface mining industry is the excavation equipment used both to strip the overburden and remove the actual orebody. Two of the more prominent pieces of equipment are the electric power shovel and dragline. These two types of equipment have increased significantly both In size and number over the last decade.Wire rope plays a significant part in the operation of these machine s. Proper selection of the correct wire rope as well as proper maintenance procedures, can result in a major saving of a mine's wire rope consumption.The most prominent ropes for shovels are the hoist ropes. Some shovels also employ crowd and retract ropes. Boom pennants are manufactured from both wire rope or galvanized bridge strand.The most prominent ropes for dragline excavators are hoist, drag, and dump ropes. Some dragline excavators have boom hoist ropes, and most large dragline excavators have a boom suspension system using galvanized bridge strand."

Jan 1, 1983