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By A. J. Lynch

Mineral commimition is an important and expensive industrial process and modern comminution circuits are complex There is considerable economic incentive to optimize circuit design and performance and to operate circuits at maximum efficiency, and these aims may be achieved by setting up mathematical models of the units in a circuit on a digits, computer and studying the behavior of simulated circuits. Models of grinding mills and cyclone classifiers which may be used for this purpose are discussed. The use of these models for design and optimization is discussed and particular mention is made of the factors which are important in circuit control. A digital computer-based automatic control system which has been successful in practice is described

Jan 1, 1972

By J. Gordon Scott

The Iron Ore Company of Canada has now been operating a computer for the grading or blending of direct shipping ores for two years. This paper deals with the computer application pertaining to the grading of direct shipping ore. It consists of five sections. The first part deals briefly with a description of the operation of the Iron Ore Company of Canada; the second with the source and flow of the various data required to grade or blend ore; the third briefly outlines the computer programs used in this application; the fourth illustrates the mathematical approach used to properly blend ore. The final section briefly describes other technical computer programs.

Jan 1, 1964

By James McManus

The Lornex mine is located on the Southern slope of the Highland Valley in South Central British Columbia. The large low grade deposit was discovered in 1964; stripping began in 1970, and the mill started commercial production in October of 1972. The orebody is classified as a complex porphyry type having as major constituent quartz diorite, with varying amounts of quartz, grano diorite, and porphyry. A substantial degree of alteration is evident in the host rock, and this became the key factor in major equipment selection for the grinding section. A pilot plant was constructed on the property capable of treating 100 TPD of ore. The ore was mined to be as representative as possible of the entire orebody by sinking a shaft and cross cutting the deposit underground.

Jan 1, 1975

By Kenneth A. Grace

Introduction The 1980s have not been kind to the mining industry, especially in the United States. As mineral commodities prices plunged, marginal producers were squeezed out and then major players were forced to cut back or close down operations. Base metal miners suffered the most. Gold was all that glittered. As had been the case throughout min¬ing's history, exploration activity was an early victim of these depressed conditions. Mining companies had to economize drasti¬cally and exploration was deemed a nones¬sential activity. Funding for new explora¬tion ventures dried up as mining was seen as a poor investment. A national magazine even proclaimed the death of the industry. Indeed, ignoring matters of independ¬ence of supply and the relationship of min¬eral production to national security, it was argued that mining was but a small cog in the overall scheme of things in the United States. The industry made a relatively small contri¬bution to the gross national output. We were becoming a service industry economy, re¬member? But what of those countries where mining plays a major role in the economic well-being? In some, mining is the national economy. In a few specific cases, special conditions actually brought prosperity. Copper production in Chile is one example. There, high grade copper, low production costs, and a technically advanced industry reaped the benefits of mine closures else¬where. In most other cases, however, par¬ticularly in the lesser developed countries, whole economies were devastated. This article will show what one major mineral producer, Canada, did to ensure the survival and even growth of its minerals exploration activity during these lean years. Background While Canada is among the world's mining leaders, mining is not its dominant industry. Still, it plays a far more important role than in the United States. It is a major earner of foreign exchange, currently accounting for about 25% of the total value of exports. Through spinoffs and a multiplying effect, it is a significant employer. In the far north, particularly, mining is the major nongovernment industry and a leading factor in the opening up of frontier territory. The industry cannot be allowed to die because it is often the main economic underpinning for vast, remote areas. Thus, exploration for new deposits cannot be cur¬tailed significantly without it having a long¬term negative impact on the very fabric that melds such a large, sparsely-populated ex¬panse of country into a nation. Over the years, Canadian governments have employed various means to encourage the development of new mines. Often, these incentives were tax-oriented, such as the three-year income tax holiday that applied to new mines in the 1950s and 1960s. The advantage of the tax connection is that any such incentive policy can be applied across the board to the 10 provinces and two territories that make up the federation of Canada. This is important because mining, except for the two federally-administered northern territories, comes under provincial government jurisdiction. Mining taxation is a complex give-and-take between the central and provincial authorities. In Canada, expenditure on mineral exploration is an allowable cost against reve¬nue for tax purposes. This works well pro¬vided there is some revenue from which to deduct. New exploration companies, those with no income from mining activities, de¬rive little benefit from this type of tax provi¬sion. Similarly, in times of depressed prices and reduced or nonexistent profits, the tax deductibility of exploration spending loses its value even for the major mining compa¬nies. To encourage exploration in Canada during the lean years, a different sort of incentive was required. The instrument used during the 1980s was again tax connected. It became known as flow-through financing or, simply, flow-through shares. When it assumed its final shape, it worked dramati¬cally. Flow-through shares Flow-through shares are so-named because they permit tax benefits earned by a corporation to 'flow-through' to the share¬holder. Basically, when an investor buys a flow-through share and the proceeds de¬rived by the company from this transaction are used for Canadian exploration, the in¬vestor can claim a deduction for tax pur¬poses as if the exploration expenditure was made by him personally. Flow-through shares go back to the early 1970s when Canada revamped its mineral income tax law. At that time, it permitted full deduction of exploration and development expenditures and provided for an automatic depletion allowance of one¬ third of operating profits from mining. There was also the three-year income tax holiday for new mines. New legislation replaced the depletion allowance with an earned depletion arrange¬ment whereby one dollar of depletion was earned for every three dollars spent on ex¬ploration and development. This earned depletion was `banked' during a transitional period (to 1974). After that it could be deducted from resource profits up to a maximum of 25% of such profits in any one year, with the excess carried forward. To promote exploration and mine de¬velopment in Canada, the earned depletion allowance plus the continued deductibility of exploration and development expendi¬tures permitted the recovery of risk capital before taxation. The three-year tax holiday, however, disappeared. Also, mining com¬panies that did not reinvest in exploration lost the depletion allowance benefit.

Jan 1, 1989

By I. Yaniv

The magneto-hydrostatic method can be used today to separate slightly magnetic or non-magnetic particles according to differences in their specific gravities and magnetic susceptibilities. The classical approach is to effect stratification prior to separation. This paper discusses some of the significant parameters which bear on the design and pattern of the expected stratification in the separation cell. As the characteristics of the magnetic field, and consequently those of the magnetic forces, are determined by the geometry of the poles, this subject is treated first. In this context a new approach, whereby the range of stratification is extended, using positive as well as negative gradients, is presented. Finally, the effect of the relative size and shape of the particles on stratification is discussed.

Jan 1, 1978

By Peter J. Szabo

In 1980, a caravan of representatives of Japanese trading companies debarked on the shores of the United States bearing gifts of watches, electronic games, and radios. In early 1983, we find in a parking lot of a major U.S. coal company, a haggard general manager of marketing returning to the Orient with a box under his arm of trinkets of his own; cross pens with company logos, alarm clocks, etc. The tables have turned, but our fellow sitting in a jet plane over the Pacific Ocean had only to heed the warning of the famous 19th Century poet well familiar with the ways of the Far East. Kipling said; "And the End of the Fight is a tombstone white and with the name of the late deceased, And the epitaph drear, a fool lies here who tried to hustle the East."

Jan 1, 1984

By B. Anameric, S. K. Kawatra

Pig iron nuggets were produced in a laboratory scale furnace at Michigan Technological University. These nuggets are produced from pellets consisting of a mixture of iron oxide, coal, flux, and a binder, which are heated to 1450°C.These pellets then self-reduce to produce a solid, high-density, highly metallized (96.5% Fe) pig iron. During the nugget production process, a separate slag phase forms that cleanly separates from the metal. The physical and chemical properties of the pig iron nuggets are similar to pig iron produced by blast furnaces, which is distinct from Direct Reduced Iron (DRI).

Jan 1, 2004

By J. Bartrum

Kidston Gold Mines is a 14 000 tonnes per day rated operation located 280 kilometers west of Townsville in Queensland. The principle shareholder is Placer Development Limited. Kidston's orebody consists of 44.2 million tonnes graded at 1.79 g/t gold and 2.22 g/t silver. Production commenced in January, 1985, and despite a number of control, mechanical and electrical problems, each month has seen a steady improvement in plant performance to a current level of over ninety percent rated capacity.

Jan 1, 1985

By K. Hartman

Certain external forces affect the manner in which business is conducted. and in recent years changes in the business environment have altered how some of these external forces affect the management of a business. These changes must be understood and considered in definition of the strategy of the business. Implementation of the strategy must assure commitment from all departments within a company, and this commitment sometimes involves compromises to assure that a department's goals mesh with the overall business objective such compromises must be externally motivated. i.e. for benefit of the customer. Complete implementation transcends internal departments to all aspects of managing the efforts in the marketplace.

Jan 1, 1989

By Marshall D. Himes

The Pima mine, 39,000 ton per day copper mine, is located 17 miles south of Tucson, Arizona. The mine is in a sequence of Paelozoic and Mesozoic sediments striking east-northeast and dipping southeasterly intruded by a Tertiary quartz monzonite porphyry. The Paleozoic Permian(?) dolo¬mites, limestones, and sandstones have been altered to talc-silicate skarn, marble and quartzite. The overlying Mesozoic Triassic(?) clastic sediments have undergone some recrystallization and hydro¬thermal alteration. The clastic metasediments are divided into three distinct lithologic units, lithic arenite, arkose, and inter¬bedded and overlying black argillite. Three types of hydrothermal alteration in the clastic rocks are propylitic alteration (epidote, chlorite and quartz, with or without sericite), quartz-sericite alteration, and potassic alteration (K-feldspar and quartz, with or without sericite and chlorite). The porphyry has undergone potassic alteration. Dominant structures are an east-west post mineral fault in the western part of the pit, and strong low angle faulting and shearing which truncates the ore body at depth. Two joint sets, one parallel to bedding and the other at right angles to bedding are prominent in the mine. Faulting is in two dominant directions, one striking northwest, dipping northeast and the other striking northeast, dipping northwest. Mineralization is predominantly disseminated pyrite and chalcopyrite, and molybdenite-quartz veinlets. There are lens important amounts of magnetite, hematite, sphalerite, galena, tennantite and bornite. Mineralization is believed to be both structurally and chemically controlled.

Jan 1, 1972

"Above ground, elevated belt conveyors that span more than 200 m (656 ft) between support points can cross valleys, rivers, forests and buildings with a minimal footprint. The cable bridge conveyor (CBC) is a new type of suspension bridge based belt conveyor system that has long spans between support points. It combines a typical belt conveyor and an improved simple suspension bridge to form a conveyor bridge. The improved simple suspension bridge places a widened bridge deck directly on suspended cables, without the need for high truss towers. The benefits include reduced cost and increase aerodynamic stability compared to conventional suspension bridges. The CBC’s compatibility with current belt conveyors allows versatility in application.A belt conveyor is a ubiquitous material handling system. Conveyors can be placed directly on ground or elevated above ground by support structures. Considerations of cost, design, environment, civil work, safety and process requirements are all factors in choosing the ground-based or elevated conveyors (Zhang, 2014). The ground-based conveyor has the lowest structural cost when the conveyor is placed on an existing road. Maintenance access is easy and straightforward. Compared to the groundbased conveyor, the elevated conveyor can cross existing buildings and structures, give passage to traffic beneath the conveyor, has a smaller footprint and requires less civil work to pass mountainous areas. The drawback of the elevated conveyor is higher structural cost, which can be compared with savings in civil work and other benefits. Conventional elevated conveyors are supported by rigid truss-type structures, with a typical span of 15 to 25 m (50 to 82 ft) between concrete support bents or steel trestles. Triangular truss, using steel pipes instead of hot rolled steel sections, is more efficient. The typical span of a triangular truss-supported conveyor is around 30 to 40 m (100 to 130 ft), while the weight is about 10 percent less than conventional box truss with a shorter span (Jennings, 2013).Long-span elevated structures based on suspension bridge is another step forward in increasing the distance between support bents, reaching 100 to 400 m (330 to 1,312 ft) and beyond. The wide distance between the support points of an elevated conveyor offers unique benefits. The conveyor can cross rivers, valleys, highways, forests and other obstacles with minimal footprint and reduced civil work. The versatility from long-span conveyors makes bulk material transportation over previously impossible terrains now a feasible option."

Jan 1, 2014

By T. Reed Scollon

Before we can attempt to answer the question of what can be expected from coal research, let us examine why research is done in other fields and what others expect for the money they spend on research and development. Up to 1900 almost all organized research was carried out at universities. Most of the support came from the university, and by present standards the amount of research was extremely small. The motivation for university research was basically discovery of new phenomena, with the objective of advancing knowledge. Side by, side with this organized effort was that of individual inventors who were primarily responsible for applying this new-found knowledge to useful purposes. During this period inventors were rarely supported by anyone, and experimentation was carried out either in their spare time or at the expense of earning a living. Men like Edison, I believe, were the first to demonstrate on a large scale that one could systematically apply newly discovered scientific principles to inventions that would serve useful purposes and would return a profit to those engaged in the effort. The tremendous expansion in research therefore began with the realization and demonstration that the scientific discovered could be applied in such a way as to return a' handsome profit to those who invested in it. The motivation of many of the research personnel however, remained the satisfaction associated with new discoveries, The money to support their efforts came from those interested in a return on their investments. Since the First World War and a rapidly accelerating rate since the Second World War another important motive for supporting research has appeared--the needs associated with national defense; this type of research has been supported almost exclusively by the Government.

Jan 1, 1959

By Tsutomu Yanagase

Non-ferrous smelting industry in Japan often had the severe problems about the over production of sulfuric acid. There has been such a closed relation between amount of sulfuric acid from non-ferrous smelting industry and the products of copper, zinc and lead metals that the production of one ton of copper accompanies three tons of H2S04. When the proper balance exists in both markets this situation certainly brings bigger profits. In Xining and Metallurgical Institute of Japan the research commitee concerned with the fixation process of sulfur in non-ferrous smelting industry was established in 1977 and continued the activity for four years untill 1981. This paper will introduce some of the activities involved in the report published by the committee.

Jan 1, 1982

By Donna Wallace

Past EPA groundwater monitoring programs required that contamination not leave the boundaries of a disposal facility. New regulations under the Resource Conservation and Recovery Act (RCRA) require that once hazardous waste constituents are detected beyond the limits of the disposal area, a program to define the rate and extent of contaminant migration must be instituted. Future regulations are likely to include even more stringent groundwater protection criteria. The implications of both the existing and probable future groundwater protection and monitoring requirements in terms of using geologic containment as a means of disposing of hazardous waste are explored in this paper.

Jan 1, 1981

By William E. Horst

Ore grindability data based on various techniques to measure comminution characteristics are used to evaluate the crushing and grinding efficiency in mineral processing operations. The importance of achieving improved comminution efficiency, in terms of energy consumption, has been emphasized by recent increases in the cost of electricity. From a theoretical standpoint, the objective of a grinding operation might be expressed as maximizing the production rate at a given grind size while minimizing the energy consumption per ton of material ground. To achieve this objective in an industrial operation presents a challenge especially in view of changes in the raw material which are normally encountered. Various procedures1-5 used to determine energy-size parameters and grindability measurements have been reported. The proposed relationships between particle size and energy consumed have much in common between many of the techniques for measuring grindability. Probably the most widely used parameter to measure ore grindability in recent years is the Bond work index6, Wi, which is defined as the kw-hr per ton required to break from infinite size to a product size of 80 percent passing 100 microns. If the breakage characteristics of a material remain constant over all size ranges, then the calculated work index would be expected to remain-constant since it expresses the resistance of material to breakage. However for most naturally occurring raw materials differences exist in the breakage characteristics depending on particle size, which can result in variations in the work index depending on grind size. Consequently work index values are generally obtained for some specified grind size which typifies the comminution operation being designed or evaluated.

Jan 1, 1975

By Wilbur H. Smith

Geologic mapping techniques at the Bingham Mine have evolved as rapidly expanding applications of geological data have caused new methods to be utilized. The most significant changes in method have been in the preparation of the base map and in computer application of collected data. Formerly maps were prepared by surveying with transit or plane table. Currently a photogrammetric map, on the scale of 1-inch equals 200-feet, is prepared semi-annually and continuously updated to keep pace with the removal of more than 350,000 tons of material daily. Larger scale bases for specific problems, such as areas having unstable slopes, are prepared by use of aerial and terrestial photography and photo mosaics. Note sheets designed for computer application enable fast processing of the data. Application of geology at the Bingham Mine has been increasing rapidly in recent years. The effect of structure, rock type, and alteration on slope stability, the relationship of sulfide mineral distribution to concentrating results, the effect of rock and mineral types on waste dump leaching, and requirements of a reliable internal source of silica flux for smelting are a few of the problems which require the collection and application of geologic data.

Jan 1, 1968

According to the Balandin's (1) "multiplet theory of catalysis", adsorption can occur only if atoms of the reactant molecules are congruent with surface atoms of the catalyst. Such a condition calls for certain definite geometrical relationships between the reactant molecules and the atoms at the surface of the catalyst. If such a match or geometrical 'fit' is not provided, the surface reaction will not take place. An appropriate analogy to this may be the lock and key theory that enzymes should fit a substrate just as a key fits a lock. Similar geometrical considerations in adsorption studies were made in connection with the flotation of minerals. Gaudin(2) and Gaudin and Preller (3) proposed that if the dimensions of collector ions are in registry with the mineral lattice, an ordered layer of adsorbed species is formed. They explained that the structural fit is one reason for good flotation of galena with xanthate. In another study, Bachmann (4) attributed the selective flotation of KC1 from NaCl with amine to the fact that the lattice parameter of the amine collector is closer to that of KC1. Schubert(5) investigated the flotation of various nonmetallic minerals with amine and pyridine, and related the dimensions of the collector ions with the anion distances of the mineral surface. He concluded that good flotation is obtained when the tolerance is within 20%. The geometrical theory has also been used by Groszek (6) to explain the preferential adsorption of n-paraffin onto the basal plane of graphite. The geometrical theory has thus been found useful in explaining adsorptive properties of an adsorbate relative to the substrate structure. The purpose of the present work is to examine the possibilities of a geometrical fit between sodium dodecyl sulfate and Cu(OH)2 surface, and to construct a crystallographic model of the surface compound.

Jan 1, 1974

By J. Kallioinen

Theoretical considerations, experimental results and plant experience have lead to a new design concept called the unit reactor approach. It has been successfully implemented to the largest flotation cell on the market, the 4000 cu ft OK TankCell. The work has also lead to a new operating idea called size specific flotation. The paper discusses these concepts in the view of full scale field experiments. In large scale porphyry copper flotation experiments conducted in Chile the new large TankCell with its new low energy input Free Flow mechanism out-performed the more conventional designs. The recovery was substantially better, especially in the coarse fractions. In some experiments the difference in total recovery was up to 10%-units and the savings in total energy consumption at the same time over 40%.

Jan 1, 1995

By S. B. Castor

Proceeds from industrial mineral mining in Nevada were approximately equal to those from metal mining during the barite boom in the late 1970s and early 1980s; however, since then the economic importance of industrial minerals has been overshadowed by gold mining (Fig. 1). The total value of industrial minerals mined in Nevada increased by about 60% during the 1980s, reaching an estimated $306 million in 1990 before falling slightly in 1991. The state's most important industrial mineral commodities, in order of estimated value, are aggregate, lithium carbonate, diatomite, lime, cement, gypsum, barite, clay, silica, and magnesia (Fig. 2). Industrial minerals produced on a smaller scale are colemanite, dimension stone, dolomite, perlite, salt, and zeolite. In 1991 industrial mineral commodities other than aggregate were produced at 39 operations in Nevada. Most of these operations are located near the two major metropolitan areas of the state, or along the major transportation routes (Fig. 3).

Jan 1, 1993

General. Data for the operating information given in the 15 tables in this chapter was obtained from voluminous questionnaires sent to over 100 operating companies in 1972. There has been a considera¬ble change since then in supply and power costs and many companies have had expansions or revisions since that time, so it must be realized that information is valid for the year 1972. This is true except for the three new properties of Sacaton, Metcalf, and Pinto Valley. These three operations started up since 1972 and all information for them was obtained in 1975. The questionnaires were sent to all major copper properties throughout the world as well as to many smaller units and to some mines that had complex or unusual conditions. Properties for which no information is given did not submit completed questionnaires. Several operations were unable to supply information requested be¬cause of company policy prohibiting it. However, data is presented for 75 different operating properties. The reference number of the left-hand column is the same for all 15 tables of data. If the company had several operating properties as of 1972, then subsequent properties use the same number but a different letter. For example, Anaconda's property at Butte, Mont., is IA, whereas Anaconda's (now Anamax) Twin Buttes property in Arizona is IB. Table I gives general data for the properties including exact loca¬tion, milling rate, pertinent assay values and recoveries, and a brief listing of ore and gangue minerals. It was not possible to obtain any more information from the properties in Chile except that given in Table I. Crushing. Crushing plant operating data is given in Table 2. This table gives data on the crushers, feeders, and screens used at each property. The data obtained on feeders was confusing, but, rather than completely eliminate this information, it was decided to report it as given. The confusion lies only in the description of where the feeder is located. Where a primary feeder is listed it was not possible to determine if this feeder was on primary feed or primary discharge. For secondary feeders it is known that the feeder listed usually is feeding the secondary crushers, but at some properties it is handling the secondary crusher discharge. The same reasoning holds true for tertiary feeders-they handle either tertiary feed or discharge. This table contains a voluminous amount of data. A column giving tons per day per square foot of screen area would have been very informative, but some properties included circulating load in the feed rate and others listed new feed only, so calculations were meaningless. Autogenous Mills. The use of autogenous or semiautogenous mills for any property must be given serious consideration in the future. Table 3 lists data for four properties that are fully autogenous and four more semiautogenous mills that use balls to supplement the chunks of ore. This method of grinding is especially applicable when the ore is of such a nature that crushing problems would be severe, such as when ore is wet or sticky or contains a lot of fines. Paradoxically, it should also be considered when ore is tough and hard and blocky because then the competency of the ore means it can serve well as the grinding media. Where the ore varies greatly in hardness, as at Cyprus Pima and Lornex, semiautogenous grinding has been especially beneficial with capital costs and operating costs both 10-20% lower than could be obtained with conventional crushing and grinding. Rod Mills. For a great many years the standard milling operation used two- or three-stage crushing followed by open circuit rod mills and then ball mills in closed circuit with classifiers of some kind. A surprising number of properties crush to the fine size of about 3/8 in. and then use ball mills only, in closed circuit, with no rod mills. It is difficult to say whether rod mill-ball mill circuits or ball mill only is the best. One can be certain of two things: (1) the argument will go on for a long time and (2) for some mills one method obviously was superior over the other. As ball mills of 14, 15 ft, and larger came into use, more properties like Duval Sierrita (16b ft diam by 19 ft long) and Bougainville (18 x 21 ft) were built with single-stage ball mill grinding. Although there are larger rod mills used, especially in the iron ore industry, the largest rod mills on copper ore are at Twin Buttes (14 x 18.5 ft) and at Gibraltar (13'A x 20 ft). Table 4 lists operating data for rod mills. If a company is listed in Table I

Jan 1, 1985