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By R. Addison, P. V. Avotins, E. Martinez, L. A. Haas, D. K. Mortenson, E. EI-Shall, R. D. Kulkarni, M. D. Flavel, S. Chong

Mineral processing activities in general reflected the economic ills of 1981 and early 1982, but in some areas the depressed state of the industry resulted in increased activity. As were all aspects of the minerals industry, processing plant operations were severely affected by the recession-prone economy, by sagging prices for primary metal products-copper, molybdenum, nickel, iron, manganese, and especially uranium-and numerous shutdowns and layoffs. Copper production by major producers in Arizona and Utah was severely curtailed; Amax, the major US molybdenum, producer did considerable belt-tightening; and the uranium industry was in a state of disaster. Even the precious metal superstars-gold and silver-were affected, with a steady decline throughout the year in world market prices. Perhaps hardest hit have been newly developed properties, particularly in the uranium industry, and old-line properties where historical development impacts today. No longer can such properties afford the luxuries, for example, of a long haul distance between mine and plant or continued use of antiquated facilities. Surprisingly enough, the very state of the economy has caused increased activity in some sectors of the mineral processing industry. In mill design, although large projects have been tabled, smaller projects have gone on, with innovations in design, often for cost-saving reasons, that will affect future designing approaches. Economic restrictions are impacting on mill flowsheets as researchers look for improvements and better, less expensive techniques. Other unit processes-hydrometallurgy, pyrometallurgy, concentration, materials handling-are impacted by the need for a better, less costly product. Although at the end of the first quarter of 1982, no major environmental legislation had been enacted, rumors persist that there will be a loosening of some of the stricter standards, both in the requirements themselves and in the time allowance for implementation. The year had seen some relaxation in how current legislation and standards are administered. For example, in OSHA (Occupational Safety and Health Administration) operations, there has been a shift toward voluntary checking of industry compliance with work rules, rather than emphasis on agency inspections. However, the industry continues to view environmental factors as having major influence on future operations and efforts to design for environmental safety are becoming almost as important as the processes themselves. Throughout the industry there has been a further focussing on project management, recognizing the necessity for tight control of budgets and schedules-and the systems used to effect them. Materials Handling Review prepared by A. T. Yu, ORBA Corp. The frenzy of coal export activities has continued into 1981. Many modern export terminals are now in construction while others have either been held up or cancelled. Economics and environmental permits have been some of the major problems. Currently under construction are terminals in Newport News, VA; Charleston, SC; and Baltimore, MD. Expansion of existing facilities at Mobile, AL, and New Orleans, LA, is also well under way. A wide variety of systems and components are being used. They include traveling shiploaders, tunnel and bucket wheel reclaim¬ers, stackers and high line trippers, and bottom and side dump-type car dumpers. Manufacturers from Japan and Europe have been participating along with domestic suppliers. As an attempt to avoid environmental problems, a system of loading and unloading coarse coal

Jan 5, 1982

By Rainer Alles, Markus Keller

INTRODUCTION For overland conveyors of several kilometres length and as well as wide for conveyors designed for high mass flows, the cost for the conveyor belting share is 40% to 50% of the invested cost 173. The German Standard DIN 22101 is used for calculation and dimensioning of - conveyor belts and belt conveyor components. Developments in rubber technology and conveyor belt design required a revision of the standard released in 1982 121, which was published in August 2001 131. New research results and publications 16-9, 13-15] led to a better understanding of the material behaviour and their influences on conveyor belts. Test and calculation methods have been established to determine the most important parameters which are related to the performance of a conveyor belt line. These parameters are • The running resistance of the idlers • The indentation resistance of the belt • The dynamic splice efficiency • The distribution of belt load in the splices, transition zones and on pulleys. As a result, new rubber compounds with low indentation losses allow the use of reduced friction coefficients and thus lead to reduced power consumption, smaller drives and lower belt tensions. The deeper understanding of the flux of forces within belt splices led to both optimised splice design and optimised rubber compounds which significantly improve the dynamic splice efficiency. Therefore, in accordance with the standard, the benefits of these technologies and the better understanding of material behaviour allow a reduction of belt strength still maintaining sufficient safety factors. Thus engineers are enabled to calculate belt tensions more exactly and users are encouraged to pay more attention to starting and braking techniques. DETERMINATION OF DRIVE FORCE According to the DIN standards the resistance to motion generally has to be determined for each different section of the belt conveyor including upper and lower run separately. The necessary drive power P is calculated as [ ] with v as the conveying speed. The total of all resistances to motion of carry and return run can be determined as [ ] FHo and FHu are the primary resistances consisting of the running resistances of the idlers, the indentation resistance of the belt, the fulling of the conveyed material and the flexure of the belt. While indentation resistance and idler resistance are measurable, they have been deter- mined to be responsible for up to 70% of the primary resistances covered by FH. Further FN is the secondary resistance that covers, for example, the resistance of feeding points and scrapers. Fa are the total slope resistances and Fs is the total of all special resistances, resulting, for example, from belt steering devices. These three resistances should be neglected in the following discussion. For conveyors where a determination of the substantial parts of the resistances to motion is not possible, according to the new DIN standard [31 a determination of the drive power is acceptable by using the fictitious friction factor) [ ] In this formula the index i identifies the individual section of the conveyor, 1 is the length of the section and MR, MG and ML are the related masses of the idlers, the belt and the load in kg/m. The fictitious friction factor f determines the ratio between the overall resistance to motion and the total of moved masses within the

Jan 1, 2004

By Geoff W. Seward, Charles J. Maes

INTRODUCTION The work of the metallurgical engineer engaged in developing a leach, solvent extraction electro- winning process usually begins in the laboratory and generally proceeds via pilot plant testing before finally resulting in a commercial operation. The path leading to the development of the eventual process will involve a test program on leaching in order to derive information on the amenability of the copper-bearing material to acid dissolution, under various conditions. Commonly in North America the leach process of choice is either dump or heap leaching but it may also be in-situ leaching or the treatment of mine waste- waters and bleed streams. In the past, agitation and vat leaching have also been included in the list of options. Currently the economics of copper production dictate that only material of mineralogy and grade, capable of being leached without prior milling, will lead to a viable process. This is not necessarily true in other parts of the world where grades are higher and milling costs lower and therefore this paper con- fronts all the techniques available to the metallurgical engineer in terms of the evaluation of the solvent extraction process. Understanding the objectives of a laboratory and pilot plant evaluation of a solvent extraction route is important and these are described in some detail in this paper. Of at least equal importance is understanding limitations of such a test program and this aspect of process development is also discussed with reference to the kind of equipment and experimental practices that have been shown to produce results consistent with the objectives. WHERE TO BEGIN? At the inception of a project much information is developed on the variables of the leach process and indeed in some instances the type of leach that best suits the ore to be treated is the subject of intense investigation (Wadsworth 1983). The decision to treat the leach solution by solvent extraction focuses attention on the selection of the extractant most suited to the nature of the chemical composition of the solution. A laboratory screening program will probably need to be arranged in order to assist in narrowing the options and the following is suggested for this initial screening. Selection of a Representative Leach Solution This is preferably obtained from leaching a representative sample of the ore under conditions likely to pertain in the commercial leach circuit. As the conceptualized circuit flow sheet will undoubtedly involve the recycle of aqueous solutions via the leach, then it is desirable to know the nature of and the likely level of the impurity ions in the solution as well as the concentration of copper. The other most important parameter that is required is the free acid (Anon, Acorga Analytical Method) content of the solution. As a rule of thumb, it is always true that recovery across SX is maximized as the pH of the leach solution rises. Whilst a high pH may be desirable for SX recovery, it is not always desirable for the pH (or more correctly, the free acid) of the leach to rise too high. The working range, therefore, tends to be between 1.5-2.5 pH. At an early stage in process development it is likely that a number of ill-defined conditions will exist, making it difficult to decide on typical leach conditions in which case the screening tests should be carried out using a synthetic leach solution prepared from laboratory chemicals. In doing this the copper and free content should be carefully controlled along with the appropriate addition of major impurity ions as their sulphate salts. Preparation of Suitable Organic Solutions Manufacturers information sheets on the reagents to be tested are required at this stage The information necessary to make an informed judgment on reagent performance is: Copper Uptake Value. This will indicate the amount of copper that can be extracted by a reagent as a function of its operating concentration in a

Jan 1, 1986

By S. Tavani, R. E. Browner, R. Dunne

Lead is used in CIP/CIL circuit to increase the leaching rate of gold from ores. At least four mechanisms have been proposed for the action of lead in gold leaching circuits: (I) precipitation of sulphides as highly insoluble lead sulphides preventing consumption of cyanide and oxygen; (2) su,face reaction on sulphide particles forming an insoluble lead sulphide layer peventing dissolution of those sulphides; ( 3) precipitation of lead sulphide, which undergoes further oxidation to soluble lead sulphate recycling the lead to solution,· ( 4) contact reduction of lead onto the gold szaface which then acts as a secondary oxidising agent. Rotating disc studies using a pure gold disc show that small amounts (5ppm) of sulphide ions are sufficient to significantly reduce the leaching rate of gold. Lead increased the leaching rate at small concentrations but at higher levels decreased the rate of leaching. The detrimental effects of lead were only found for a pure solution when leaching the gold disc. Ores mediate the amount of lead available by ads01ption/reaction, thus, reduced leaching rates from excess lead are not serious even when 500ppm of lead ions are added to the sluny. The detrimental effects of sulphide ions could be countered by lead addition during the leaching process. A penalty, in the form of reduced leaching rate, will occur the longer lead addition is delayed. A time lag was noted between the addition of lead and the increased leaching rate when a large concentration of sulphide ions was present.

Jan 1, 2000

By A. E. Isaacson

The Bureau of Mines is studying the effect of supercritical water, at 4000 C and 3,500 psi and subcritical water at lower temperatures and pressures. on mixtures of minerals and metals to determine the possible applications of water at high temperature and pressure for processing these materials. This research was conducted using a flow-through bench-scale system. Copper-bearing minerals studied were chalcocite, chalcopyrite, covellite, and cuprite. In general, mixtures of copper minerals and pyrite reacted to form bornite. Intermediate phases formed were chalcopyrite and digenite. Similar reactions occurred between pyrite and metallic copper. A mixture of chalcopyrite and pyrite was inert in supercritical water. The reaction between cuprite and metallic zinc yielded metallic copper. The cuprite was reduced by hydrogen generated by the reaction between metallic zinc and water. None of the reactions occurred exclusively in supercritical water, but also occurred in water at high temperature and pressure below the critical point. Experimental results did show that a dual-reaction process, consisting of solid-state diffusion and fluid transport, was occurring.

Jan 1, 1989

Disposal of solid and liquid wastes from mining and milling operations has become a focus of attention in recent years. Consequently, the geotechnical engineer is more frequently associated with design of disposal facilities. Jack Wulff, a representative of one consulting firm with experience in this field, talks with ME about the geotechnical engineer's contribution. Mr. Wulff, mine and mill waste disposal today is receiving more attention-and many more dollars-than in the past. Regulatory agencies have promulgated demanding requirements concerning mill waste (especially uranium mill waste) and specialist consultants are frequently being called in to design disposal systems. What can the experienced geotechnical engineer add to the development of waste disposal facilities? It's true that geotechnical engineers have recently become more visible in the minerals sector, but we've been around mining for a long time-as foundation engineers for mills and mine support buildings, and for geotechnical aspects of open pits, pipelines, railroads, roads, and so forth. We've also designed water supply dams, which could be considered recursors of tailings dams and other forms of disposal systems. Let me show by example what geotechnical engineering can contribute to waste disposal facility design. I recently was asked to look at several small wastewater impoundments which had failed. The design of the earth embankments appeared, at first glance, to be rather conservative. They were only about 3.4 m high, the slopes were 3 to 1 (horizontal to vertical), with about 24 m of bottom contact with the earth foundation. But there had been three episodes of dike failure in a few months, all upon initial filling. The problem was the nature of some material in the foundation that was also used as structural fill-a dispersive clay that readily deflocculated and eroded on contact with water, especially with seeping or flowing water. The design did not include the defensive measures required to use such materials confidently in water retention structures. Apparently, the designer did not recognize the potential problem posed by the unusual soil characteristics. That's the sort of engineering information fundamental to geotechnical engineering, but not necessarily a part of the civil, structural, or mining engineer's professional training or experience. This difference in expertise is not simply a matter of factual knowledge-it also affects the design process. The structural engineer can design a structure to fit the client's functional needs and can specify the materials (grade of steel, PVC, concrete, etc.) to meet the demands of the design. The geotechnical engineer's design process is somewhat different, since we work with natural materials, not man-made materials produced according to specification. We first have to establish what kinds of materials are available (usually directly from the chosen site, since importation of materials becomes expensive). Then we determine the engineering properties and characteristics and, finally, design the structure to fulfill the client's requirements within parameters dictated by available materials. In brief, the geotechnical engineer works with naturally-evolved, not man-made, materials and uses design techniques developed to accommodate that fact. Because no two sites are exactly alike in configuration, structural (geologic) characteristics, or available materials, there will be unique design and judgmental questions to be resolved on virtually every project. You said that water retention dams could be considered the precursors of tailings dams-you probably had a specific technical relationship in mind. There's a very strong carryover of methodology from earth dam design, where the technology developed and where it has become very refined. In designing a tailings impoundment or similar facility, essentially the same procedures of field sampling are involved (with a geotechnical engineer or an engineering geologist directing the program since representative

Jan 7, 1980

By Victor F. Hollister

Introduction Trends of successful discovery technology and psychology emerge from a thoughtful study of various companies' exploration programs. These subjective patterns can be generalized into groups of factors for discussion. Here, for convenience, factors that influence exploration success are separated into management and geologic concerns. Most successful discoveries have a demonstrably favorable management combined with a technically competent geologic input. Both are required. But the management input is decisive. Management factors include the correct definition of management's role; cost of exploration; time needed for exploration; commodity selection; and the fostering of autonomy, creativity, and confidence in the geology department. Geologic factors include imaginative technical competence (field as well as academic), correct development and use of empirical exploration or prospecting models, and dedication. Success comes to those entities that are properly managed and have technological competence. A management team that directs a company's business has been compared to a dynasty. The dynasty lays out policy and follows up with appropriate action. In that management's power is pervasive, the term is appropriate. Management's role is, however, more important. Many examples can be cited where the geologic input was impeccable. But management somehow snatched defeat from the jaws of victory, and the exploration success was turned to a third party's profit. Management Factors Management's role can be broadly generalized to four parts. These are to identify the commodities it seeks, define its part in the exploration process, develop a functioning exploration department, and have the desire to succeed. It must have confidence in its geologists and delegate to them the authority and responsibility they need to operate successfully. Head office management cannot do the thinking for a field staff thousands of kilometers away. There is no substitute for confidence and delegation of authority. Successes came to those who had the freedom to act. Motivation is a management requisite. Management's role is to prevent destructive, internecine political battles within the corporate structure. Most large US mining corporations have well known histories of political strife that have damaged their exploration efforts. Management's role must, above all, include the desire to succeed. There are cases where management has been confronted with a commercial exploration success, but their reaction is to request additional study or exploration. Perhaps the problem of bringing a commercial find into production is beyond their capabilities. But a bona fide discovery sent back for additional work commonly is lost due to that management. The cost of exploration is a factor that management must accept. A variety of studies made during the past 40 years shows the cost per discovery to be $25 million, $38 million, $200 million, or even $290 million. These figures are derived by dividing the total exploration expenditure by the number of discoveries. However, successful management dynasties have a much lower cost per discovery during their management regime. Asarco, from 1948 through 1963, had one of the lowest cost discovery rates in the world. Duval Corp., from 1948 through 1968, had comparably low discovery costs. Placer Development, from 1955, was equally successful. Western Mining in Australia has had one of the longest lived dynasties associated with exploration success. Time is vital in exploration success. Most successful exploration case histories stress sufficient time in project exploration so that the target is well tested. A large target cannot always be adequately evaluated by a few holes (strat or concept testing). Serendipity helps in exploring large targets, but it best operates in a lengthy program. Numerous case histories include pleasant surprises. But these came mostly after the 10th hole. Commodity markets are important factors governing exploration success. Management's decision to explore for a specific commodity can doom its effort if that product suffers from severe oversupply. Unquestionably, progressive copper price increases from 1948 through 1968 helped convert marginal porphyry copper discoveries

Jan 8, 1985

By Basar Arioglu, Jaeung Kim, Mehmet Öztürk, Jinmoo Lee, Dongho Lee, Taek-Kon Kim

"Istanbul Strait Road Tube Crossing Project (Eurasia Tunnel) includes 3.34 km of a bored double-deck tunnel under the Bosphorus Strait, at a maximum depth of 106 m from the sea level, and 1 km of twin NATM tunnels on the Asian side. The region’s variable geology, hydrology and propensity for seismic activity, combined with high water pressure and large-diameter/double-deck tunnel configuration, make the Eurasia Tunnel one of today’s most challenging and complex projects under construction. Due to the site’s proximity to the active North Anatolian Fault, the tunnel is designed to withstand a 7.5 magnitude earthquake. The tunnel penetrates through both the Trakya bedrock (on both European and Asian sides) and the alluvial sediments at the bottom of the channel. The tunnel is designed to accommodate differential displacements by introducing seismic/flexible joints at proper locations at the transition zones between rock and soft soils. Tunnel fire is also a significant design consideration for undersea tunnel due to that the rubber protecting it in close proximity of the seismic joint should resist a fire for long term safety and durability. This paper mainly focuses on the design for method of tunnel response analysis in transverse and longitudinal direction against seismic demands relating with the seismic joints. INTRODUCTION Istanbul Strait Road Tube Crossing Project (Eurasia Tunnel) will build and operate a roadway tunnel under the Borphorus connecting Kazlicesme on the European side and Goztepe on the Asian side, to provide additional road-access across the Strait and consist of three main parts as shown in Figure 1."

Jan 1, 2016

By J. E. Spencer

Mesozoic and Tertiary mineral deposits in west-central Arizona are commonly associated with Mesozoic thrust faults and Tertiary detachment faults, respectively. Quartz-kyanite rocks and pyritic quartz-sericite schists with local anomalous gold are the product of probable Jurassic argillic alteration of Jurassic volcanic, sedimentary, and plutonic rocks followed by Cretaceous thrust burial and associated metamorphism. Slivers and sheets of Paleozoic carbonates along Mesozoic thrust faults were locally sites of syn-and post-thrust mineralization. Widespread brecciation along Tertiary detachment faults resulted in increased permeability along fault zones. Elevated thermal gradients also resulted from detachment faulting and apparently caused convective aqueous-fluid circulation along detachment faults and associated Fe+Cu±Au mineralization.

Jan 1, 1988

By Fulvio V. Fonseca

The Trombetas bauxite deposits were discovered by ALLAN, as from the original work of the geologists Drs. E. E. GREIG and 3.A. STAARGAARD on the axis of the Amazon river, between Manaus and Santarem - (see fig. 1). With research licences obtained in 1965 by the SANTA RITA BAUXITA - a subsidiary of ALAN a group of Brazilian geologists, under the supervision of IGOR MOUSASTICOUSHVILLY, begins researches on the areas of Parintins, Juruti and Mathias with unsatisfactory results. In 1966, photographs obtained from the US Air Force and the Brazilian Oil Company PETROBRAS -, covering an Amazon region between Parintins, Santarem and north of Trombetas river, permitted the identification of a great number of plateaux between the Nhamunda and the Trombetas rivers. Based on this information, a research group has worked intensively from 1966 to 1967 allowing the discovery of the trihydrated bauxite in a quite large area. After five years of intense work and analysis of approximately 56.000 samples, near 500 million of tonnes of bauxite are evaluated on the several plateaux of the, area, thus insuring the commercial exploration of these deposits. Such discovery places Brazil among the detainers of the main bauxite stocks of the world and as a potential exporter.

Jan 1, 1980

By Michael J. Taylor

Introduction A prime goal in the design and operation of uranium milling waste or tailing disposal systems is to mitigate adverse effects of tailing liquid on the adjacent groundwater. Adverse effects are often defined as modifying the groundwater quality in such a manner as to have detrimental health effects on downstream users. To accomplish this goal, the following three types of systems are employed with regard to the seepage and groundwater aspects of waste disposal: Type I Systems Seepage is allowed to occur unabated from the tailing disposal facility. Detrimental radionuclides and chemical elements are prevented from causing adverse downstream effects by natural purification actions in the subgrade geologic materials and the near zone groundwater. Monitoring is required to assure the predicted natural purification is occurring. The consequences of seepage loss is minimal since the m be predicted with current investigation and analytical techniques and can be evaluated as to effectiveness during operations. Type II Systems Seepage is partially retained in a waste impoundment or leakage from a designed retention system is anticipated. Natural purification is relied on for controlling migration of detrimental radionuclides or chemical elements, or contingency planning is employed to collect and return the tailing liquid to the impoundment. Installation efforts and concern for escape of tailing liquid are greater than for Type I systems, but extra precautions to preclude all seepage are not implemented. Monitoring is required to detect leakage and/or assure the natural purification of escaping tailing fluid. The consequence for accidential excusions are moderate, and will be excessive only if massive system failure occurs. Type III Systems Seepage is totally restricted by a costly system constructed and operated with extra care. Natural

Jan 1, 1980

By Marco D. Boscardin

During subsidence, the ground surface may settle, change slope, change curvature, go into tension, and/or go into compression. In response to these ground movements, buildings and buried utilities in the subsidence area may settle, tilt, bend, distort, and sustain extension, compression and/or torsion. In order to develop measures to protect existing structures and utilities, or to design new structures and utilities to withstand potential movements in areas of subsidence, it is necessary to understand the interaction between the ground and the building or buried the utility. This paper reviews subsidence-induced ground movements, how these ground movements are transmitted to and accommodated by buildings and buried pipelines, and how these structures may alter ground movements relative to free field subsidence-induced ground movements.

Jan 1, 1986

By Brian K. Failon

Scale formation is a problem that affects many mineral processing systems because the processes require the use of large volumes of water. Scale composition may vary from circuit to circuit, but the scale deposition mechanisms and needs for prevention are often somewhat similar. Likewise, there is a degree of commonality in the prediction, detection, and elimination of scaling conditions in various water systems. This paper briefly reviews some of the conditions which lead to scale formation, as well as some of the common problems associated with unchecked scale growth. The primary focus of the paper is on the variety of chemical scale inhibitors available for use in mineral processing circuits, and the actions of each type. The means of predicting and detecting scaling tendencies are also addressed, and include both direct and indirect methods, i-e., stability index determination and chemical analysis of deposits.

Jan 1, 1986

By D. G. Bosse

Equipment choices for ultrafine grinding encompass several different types of dry and wet size-reduction devices These need to be put into functional perspective for systematic analysis of capabilities and limitations versus processing requirements of the materials to be satisfactorily ground Particle strengths plus maximum and average sizes are the primary variables controlling grinding action requirements and equipment options for efficient processing These are fairly well understood and provide the starting point for decisions Particle space requirements under dynamic processing conditions vary with particle shapes and size-distributions by as much as 30X This additional major variable IS not widely appreciated and does need adequate description to provide a firm basis for selecting processing compositions and procedures

Jan 1, 1983

By Charles F. Stack

The A. P. Green Refractories Co. operates clay mines in ten states. Eight of these states have reclamation laws with which we have to comply and indications are that the U. S. Congress will pass a federal surface mining reclamation act in the near future. These regulations, in addition to the value of land in most areas, dictate that mining and reclamation be considered as a single operation. In many instances the land may be more valuable after properly planned mining and reclamation than before. Refractory clay, commonly called "fire clay" is defined as a siliceous clay rich in hydrous aluminum silicates, capable of withstanding high temperatures. It is deficient in iron, calcium, and alkalies and approaches kaolin on composition. Refractory clay is much more limited in occurrence and usage than common clay or shale. During 1971, common clays and shales were mined in 47 states with a total production of 45 million tons. Fire clay production was reported in 22 states with a total production of only slightly over 3 million tons.(1) Many of these producing areas are extremely limited in extent and production. Several are contained within a one or two county area. This reflects the unique geological conditions required for the formation or development of fire clay. The major fire clay producing areas in the United States are shown in Figure 1.

Jan 1, 1974

By Thomas P. Meloy

As the importance of particle shape in mineral processing is increasingly recognized as an major variable in predicting the behavior of both individual particles and particle systems, whether it be in dense media, froth flotation, comminution or the flow of particles, new method of shape characterization are being developed, particularly for use on image analyzers. These shape characterization methods may be broadly classified into the analytical, empirical and physical formation methods. Discussed are approaches and the strengths and weakness of each of these methods. Moreover old and new shape measuring techniques are reviewed, particularly the new image analysis methods techniques such as Fourier, Haar, Fractal, Walsh and Delta as well as a variety of other techniques such as tabling, the Cascadograph, settling and L/D ratios. Also discussed are the problems of doing shape research, current progress and the future of the field.

Jan 1, 1990

By John L. Bolles

The mineral processing engineer must have some knowledge of mineral identification, and the greater his knowledge in this field, the greater will be his potential to do his own specialty well. Most metal-bearing ores and industrial minerals require processing of some kind to produce a salable product or a material suitable for further processing. The types of treatment are many, but each one is aimed at separating a mineral or family of minerals from others. Obviously, then, it is basic to all mineral processing to identify the minerals present in the raw material and in intermediate and final products resulting from processing. Very often the mineral processing engineer will enter planning while exploration of a mineral prospect is going on. He will examine hand specimens, drill cores and cuttings, bulk samples, and materials in place. He must identify the valuable minerals, their occurrence and associations with other minerals, and the identity of diluents or host rock. An exact and detailed knowledge of the raw material will usually suggest the treatment processes that should be investigated in the development of the most suitable scheme for that particular raw material in that particular location. Physical properties of a mineral often lead directly to a process for separating that mineral from others. Some well-known examples of these are: magnetic separations for such minerals as magnetite, rutile, ilmenite; gravity separations for gold, silver, galena. cassiterite; flotation separation for most sulfides; distillation of mercury from cinnabar; and selective dissolution in specific solvents such as halite or sylvite in water, gold and silver in cyanide solutions, copper oxides, carbonates, sulfates and silicates in dilute sulfuric acid. These processes and many others are described in detail elsewhere in the Hand¬book and so it is not appropriate to give details here, except to emphasize that processing is aided greatly by complete mineral identi¬fication. Developing a treatment scheme for a new mineral discovery is an exciting assignment fag the mineral processing engineer, but much more of the usual work relates to quality control in existing plants. Here too, mineral identification is important. Some processing is aimed toward producing an end product which will meet exacting specifica¬tions regarding purity or allowable diluents. In this situation it is vital that contaminants be identified so that the process can be adjusted

Jan 1, 1985

By Arpad E. Torma

The introduction of biotechnological principles in hydrometallurgy has created new opportunities and challenges for the industry of mineral processing. During the 1950's and 608s, the mining wastes and unused complex mineral resources have been successfully treated in bacterial assisted heap and dump leaching processes, especially for the production of copper and uranium. The economic viability of bio- leaching technology lead to its world-wide acceptance by the mining industries. During the 1970's this technology grew into a more structured discipline which is called "biohydrometallurgy". Currently, bioleaching techniques are ready to be used, in addition to copper and uranium, for the extraction of cobalt, nickel, zinc, gold and silver from diverse mineral resources and for the desulfurization of certain coals. However, in a foreseeable future the biohydrometallurgical processes may be applied also for the treatment of high- grade ores and mineral concentrates using native and/or genetically engineered microorganisms.

Jan 1, 1989

By Sundar S. Saluja

Efficient and re1iable methods of fragmentation through blasting have been sought ever since the introduction of black powder in mining operations, but the pace of investigation became faster with the discovery of nitroglycerine. The development of modern measuring instruments and the need to blast more rock with the least damage has made the study of blasting mechanics and its application more important, particularly since the oil embargo. Investigations into the practical approach evolved by Daws (1909) and the work done to make it more useful is discussed. The work of several investigators is touched upon with particular reference to the development of computer programs to simulate and optimize blasting operations.

Jan 1, 1986

By S. C. Sun

Very little information is available concerning the magnetic properties of minerals and only recently has there been any attempt to correlate magnetic susceptibility with varying chemical composition1. The work described here covers a study of the relationship and chemical composition of both the rutile and sphene types of titanium minerals. The relationship between the magnetic susceptibility of three selected mineral specimens and the applied field strength is also presented. Experimental: The equipment and procedures used in this in- vestigation for crushing and cleaning the mineral specimens and for determining the magnetic susceptibilities were the same as that employed by Spokes and Mitchell1. The particle size of-the measured specimens was limited to 270/325 mesh.

Jan 1, 1959