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By F. T. Davis

Many contributors have added to the fund of knowledge in the basic sciences related to mineral dressing during the past year. During 1964, the French edition of the Proceedings of the VIth International Mineral Processing Congress together with discussions was printed. Also, complete Preprints of papers delivered at the VIIth IMPC were published in September1. Over a third of the papers presented at VIIth IMPC dealt with fundamentals. COMMINUTION It has been postulated by Ponceleta that flaws need not exist before a stress is applied but rather the flaws are created at the tip of a propagating crack at a stress well below the theoretical breaking stress.

Jan 2, 1965

By F. T. Davis

The annual review of mineral dressing was the subject of considerable discussion at the MBD meeting in New York last February. Because the amount of material now being published is so imposing, it was generally agreed that reviewers should try only to cite the items of importance. In order to conserve even more space, it was agreed to omit bibliographies. In reading these reviews, and those of the past two or three years, one is impressed by the advances in materials handling, the enlargement and the advances in automation of unit process equipment. Although there has been development of a variety of new concentration principles in flotation, magnetic separation, et al., the design of these principles into new plants has not been widespread. The probable reason is that the plants being built today are so large and costly that few are able to face the risk of any significant degree of experimentation. There are exceptions to this; for example, some of the chemical processes, but these are usually because there was no conventional process available. This situation should change in time as the ores amenable to our conventional methods become depleted.

Jan 2, 1967

By J. M. Karpinski, R. O. Tervo

A method and equipment have been developed for measuring the impact strength of grains of brittle materials. It is shown that brittle materials develop a characteristic particle size distribution when fractured by impact. A simple mathematical model has been found to describe this distribution, and one of the parameters of the model has been designated the r value. The r value is directly proportional to impact energy and, for fixed impact energy, it becomes a useful criterion of grain strength. Data are presented on the variation of the r value as a function of sample history, initial size, energy input and number of impacts. The results are interpreted in terms of the flaw theory of brittle fracture. The view is now widely held that brittle materials comprise a strong matrix, throughout which flaws or points of weakness are scattered at random. Failure always starts at one or more of these imperfections, and planes of fracture are established by the geometry of the flaw distribution. This view has been developed extensively by Weibull 1,2 and experiments of a confirmatory nature have been reported.3,4 Thus the process of fracture or size reduction of brittle materials can be regarded as a process of elimination or creation of flaws, and the concept of strength is intimately connected with the size and history of the specimen tested. One consequence of the point of view described above is that brittle materials will fracture to yield similar size distributions, although the impact energy to produce a given amount of fracture may vary greatly from one material to another. Generally speaking, experimental investigations of brittle fracture in solids have been confined to two extreme experimental situations. On one hand, we have tests on single specimens of well-defined, but artificial, geometry and, on the other, empirical data have been obtained on the feed-product relation in a variety of mills. The first situation necessitates specimen preparation, which in the case of brittle materials is equivalent to a priori size reduction, while the second one suffers from the disadvantage that little knowledge is gained about individual fracture events. Also, the statistical significance of single specimen tests may be questioned. Our approach lies somewhere between these two extremes. We test a large population of sized specimens and yet subject each specimen to a single fracture event. In 1956 G.H. Fetterley of Norton Co., Chippawa, Ont., made the empirical observation that product size distributions obtained from impacting sized grits can be described by the following equation where R is the proportion by weight of the grain that remains on a screen having an opening x on a side, x, is a parameter having the dimensions of length, and r is a number. This equation has since been derived on a theoretical basis by Gaudin and Meloy.5 They identify x, with the initial size of the test piece and r with the number of flaws per unit length. As will be shown below, our experiments indicate that both x, and r are functions of energy and hence they should more properly be called the effective initial size and the effective number of flaws respectively. Also, our empirical data give us no basis for assuming that r represents the effective number of flaws per unit length, rather than per unit volume. METHOD AND MATERIALS The impact test machine has been designed to feed specimens, essentially one at a time, into an evacuated chamber, where they fall freely and are struck with random orientation by one or the other of a pair of flat steel vanes. The vanes are mounted at opposite ends of a steel bar, which rotates at a closely controlled angular velocity about a vertical axis. Fig. 1 shows the flat circular vacuum chamber with the cover removed, and the horizontal steel bar with the steel vanes at the ends. The cylindrical pot in which the grains are collected after impact appears at the left. Fig. 2 shows the equipment assembled for a test. The vacuum chamber occupies the central position with the variable speed drive below the table surface, the vacuum pump at the extreme left

Jan 1, 1964

By Andrew P. W. Briggs, Corale L. Brierley

A considerable economic and technical knowledge base has been amassed with the successful and sustained operation of commercial minerals bioleaching/biooxidation plants to extract copper from chalcocite ore and enhance precious metal recovery from sulfidic refractory ores and concentrates. Economic evaluation ofbio-processing must consider the value of the ore, the sulfide-sulfur requiring oxidation to achieve significant metal recovery, the time required for the biological process and, in the case of precious metal feed-stocks, the down-stream reagent consumption. Of these considerations oxygen requirement for the biologically-catalyzed oxidation of sulfide minerals is the prevailing determinant in the capital and operating costs of aerated, stirred-tank reactors for processing concentrates and bio-heaps for processing ores. Oxygen requirement is dictated by the amount of sulfide-sulfur requiring oxidation to achieve desired metal recovery. The testwork program to evaluate a project for application of biooxidation/bioleaching must be designed to insure that factors critical to economic assessment are fully quantified.

Jan 1, 1997

By M. Scherzinger, M. Dr. Mazurkiewicz

Additional progress in comminution can be achieved if the compressive crushing principle commonly used at present is changed to one where particles are fragmented by the tensile growth of preexisting internal flaws or cracks, under internal waterjet pressure. This idea was studied in a number of tests and generated results and conclusions are the subject of this paper. It covers tests with different jets imposed on rock samples during compressive load as well as without any loading.

Jan 1, 1992

Mining education in Ballarat has a long and proud history dating back to the 1870s. Today the School of Engineering continues this tradition at the University of Ballarat. The recent review of Tertiary Minerals Education by the Minerals Council of Australia has questioned the current situation regarding Minerals tertiary education in Australia and recommendations have been made regarding the future of minerals tertiary education. This paper initially examines the original recommendations made by the Minerals Council of Australia and assesses subsequent changes made to these recommendations. Secondly the paper outlines the future shape of mining education in the light of these recommendations given that they are implemented. Finally the future delivery of mining education is discussed, particularly with respect to the impact of modern technologies.

Jan 1, 2004

The Institute of Geological and Nuclear Sciences (GNS) is commencing a project to develop a National Minerals Information System (NMIS) for New Zealand . Initially, the NMIS project will focus on providing public access via a web site to existing minerals related databases maintained by GNS and some other organisations. Core components are geological maps, GERM (Geological Resource Map), REGCHEM (Regional Exploration Geochemistry), PETLAB (rock catalogue), GEOCHRON (radiometric ages), mineral deposit models, mineral deposit profiles and 3D mineral deposit GIS databases. In addition to developing the web site, the project will include upgrades of some of the databases and the production of derivative products such as mineral resource and prospectivity assessments, and mineral inventories.

Jan 1, 2004

By Dan Witkowsky

In an increasingly environmentally conscious world, mining's importance to society has often been misunderstood and even maligned by the public. Extreme and impractical ideas have often been presented to children because of the lack of accurate, timely resource materials available to educators. In the late 1960s. two mining engineers, S.P. "Pi" Warren and C.L. "Lindy" Barker, became aware of this situation. They proposed to develop a summer field course to provide a factual overview of the minerals industry for teachers. The pair believed that teachers could become better informed to educate students, and future generations, about mining. These two Colorado Mining Association (CMA) members felt that such a course could reduce much of the misunderstanding about this vital industry. This could be done by providing a balanced perspective of mining, not only for kindergarten-through-grade-12 teachers, but also for the students they would be teaching during their careers. Students who better understood the minerals industry could better formulate an unbiased view of it. The course would seek recognized authorities from industry, academia and government who would lecture in their respective fields of expertise. The course would provide a total concept of the coal, aggregate, metals and industrial minerals industries. It would include geology, geophysics, exploration, mining, processing, marketing, product applications, economic, mining history, careers, and environmental responsiblity. When possible, site visits would permit educators to view operations and to meet the men and women who are industry leaders. Teachers would pay a small tuition fee. The balance of the program expenses for each teacher would be paid through scholarships provided by industry and individuals. The "total concept" idea obtained the support of the minerals industry. The support of CMA's Education Committee and the Colorado School of Mines (CSM) was obtained in 1968. Colorado's Commission on Higher Education approved teacher recertification credits through CSM's Office of Special Progams and Continuing Education for those successfully completing the program. The first six-week series of classes presenting the total concept of the indus¬try was held at CSM in 1969. In 1977, the CMA Education Foundation Inc. (CMAEF) was established as a Colorado nonprofit corporation. The "Total Concept of the Mining Industry" (Total Concept) course was placed under its sponsorship. CMAEF is dedicated toward this continuing education program (Table 1). In 1994, the course was streamlined to four-weeks for six hours recertification credit.

Jan 1, 1997

By J. N. Murphy

The use of the National Science Teachers Association (NSTA) regional meetings as a forum to educate teachers on the role of minerals in our society has been immeasurably successful. Each year, on average about 3,500 to 4,000 teachers participate in each of the three regional NSTA meetings. At each of these meetings, nearly 2,000 teachers visit the “Minerals Coalition Booth” and receive free mineral samples and other educational support materials. Some rules of thumb for a successful booth at the NSTA are provided. Considering the level of effort for such a booth, are there alternatives? The NSTA also organizes a national annual meeting with attendance of about 20,000. All who have participated in a regional NSTA agree that the traditional approach of providing a mineral set and teacher materials for a substantial fraction of the 20,000 attendees is not feasible. Conceptual alternatives for minerals education at the national NSTA meeting are introduced and evaluated.

Jan 1, 2001

By Robert A. Clifton

It seems probable that more and more minerals will be used in plastics as time goes on. This must occur because the minerals will; aid in processability, enhance the engineering properties, reduce the cost, and above all conserve large amounts of petroleum based chemicals. This paper examines the advantages and disadvantages of using the minerals and the ability of the domestic minerals industry to support this possibly very large undertaking. In the author's opinion, it can. This talk is excerpted from a forthcoming Bureau of Mines Information Circular.

Jan 1, 1985

'Industrial Minerals - their mining and use in New Zealand' is the theme of the 1978 Annual Conference of the New Zealand Branch of The Australasian Institute of Mining and Metallurgy. This paper describes the use of phosphate rock, sulphur and potassium chloride (potash) - three industrial minerals which have enabled the farmers of New Zealand to increase production to current levels. The growth of imports of these raw materials for the New Zealand fertiliser industry is well documented in NZ Fertiliser Statistics 1977. This is the most recent of the Ministry of Agriculture and Fisheries annual publications on this Subject prepared from the detailed returns of fertiliser manufacture and sales from each fertiliser works. There are now 12 of these works in New Zealand one of the most recently established being in Whangarie where this conference is being held. Its capacity to manufacture superphosphate will shortly be 300 000 tonnes twice that when it opened late in 1964. New grinding and manufacturing equipment comes on stream early in 1979. This paper illustrates the interdependence of two primary industries, agriculture and mining. New Zealand's economy in the foreseeable future will be based on agriculture so that our standard of living is dependent on the overseas prices and freight costs of the bulk raw materials from which our fertilisers are made. For the year ended 31 March 1978 New Zealand's total exports were $3395 million, of this total $2413 million (71%) came from the products of pastoral agriculture (wheat, wool, dairy and other animal products), $291 million from forest products and $501 (15%) from manufactured exports. Approximately half of the pastoral receipts can be attributed to the fertilisers applied at a total cost of about $200 million including subsidy.

Jan 1, 1978

By Henry T. Mulryan

Since World War II, U. S. chemical companies have loosed a flood of synthetic organic insecticides. These synthetics fall into two broad categories. DDT is the best known of the chlorinated hydro- carbons and Parathion is the most famous (or infamous) of the organic phosphate nerve gas type. Insecticide poisons are not applied at full strength but as dilute sprays or dusts. This permits a broader and more efficient distribution of the active killer.

Jan 12, 1958

By W. Lorenz

The responsible treatment of natural resources, including mineral raw materials, contributes to the protection of the environment. The management of resources and the environment encompasses reduction of emission through application of environmentally friendly processes, economical use of resources, recycling and substitution, application of energy saving processes, land reclamation and recultivation, as well as a well balanced regional and land use planning. A variety of materials are needed for measures to protect the environment. Many of these materials are, or to a large percentage consist of, mineral raw materials, which become effective either directly or indirectly in their natural state or after an appropriate industrial treatment. We call them environmental minerals. Although extraction and processing of these mineral raw materials destined for use in the protection of the environment, may have a negative impact on the environment on one hand, preventive or curing measures to protect the environment on the other would not be possible without them. We have to accept certain smaller burdens of the environment, which naturally will have to be kept at the lowest possible level, in order to avoid or minimize greater damages to nature. In the broad group of industrial minerals and rocks there is a wide variety of mineral raw materials, which lend themselves for countermeasures in favor of the environment. To hamper their production and processing through excessive environmental regulations would make the protection of the very environment more difficult or even impossible.

Jan 1, 1995

By D. A. Viljoen

An account is given of the development of man's interest in the recovery and working of minerals from Palaeolithic times to the present. This is followed by a discussion of future production trends for the more important minerals, and of likely technological developments in the recovery of various minerals. The crucial importance of energy minerals is stressed, as are several other factors of significance to a flourishing minerals industry: manpower, education, financial climate, Industrial health and safety, and preservation of the environment.

Jan 1, 1979

By H. Foster Bain

FROM time to time geologists and mining engineers, impressed by the heavy demands made on our mineral reserves' by modern industry, and particularly by the steadily mounting rate of production necessary to meet that demand, have issued warnings as to the danger of exhaustion. There can be no dispute as to the fact that mineral deposits are exhaustible. New mineral, is not created to replace that taken from the earth and when a crop of mineral is once harvested another cannot be grown in the same area. The evidence of exhaustion 'of particular oreshoots, deposits, or even of whole districts is familiar to all who have mined. If one were to judge solely from the abandoned mills and prospect holes he would rightly conclude that mining is but a short-lived industry. If one were, furthermore, to assemble the data as to known reserves of almost any of the commonly used minerals, and divide them by the annual tonnage mined, he would come to the same conclusion. If, again, one were to consider the most carefully made estimates of competent men seeking to measure the earth's reserves of minerals and plot against them a projection of the curve of past consumption, he would be justified in viewing the situation with alarm.

Jan 1, 1930

By Zay Jeffries

From the title of this chapter the reader could expect an attempt to outline the anticipated shape of things to come, mineralwise. We have no crystal ball and if we possessed one we could claim no expertness in its use. In the first place no one can tell the future status of man. No one has any way of knowing to what extent peace will prevail, nor to what extent changes may occur in national sovereignties or forms of government or in international relationships. So future man is an uncertainty. Nor can we predict new developments that may result in significant changes in man's status or in the mineral industry or both. If, for example, this chapter had been written in the middle 1930's, nearly everything that has happened since in the field of atomic energy would have been missed. Yet what a vast change this has made in the status of man! Also the changes in the mineral industry have been important. A writer would have been bold indeed had he prophesied that uranium would play such an important role. But we need not confine our foggy vision to the atomic energy field. The steep rise in the use of aluminum, titanium, and germanium reflects the unpredictable in what may be thought of as the more normal pursuits. This should not discourage one from using the past and currently observable trends as bases for limited predictions. To do this, however, it is desirable to make certain assumptions about man's status without even a pretense that these assumptions have a high probability of fulfillment: 1. Only minor changes will occur in the geographical boundaries of the nations of the world. 2. World War III will not take place in the near future. 3. As a consequence of (2), man will not destroy himself by wanton use of atomic weapons. 4. Disarmament will take place, if at all, gradually rather than all at one time. Under the above assumptions the world will enjoy a period of relative peace even though the status may be one of an armed truce. The assump-

Jan 1, 1959

By Zay Jeffries

From the title of this chapter the reader could expect an attempt to out- line the anticipated shape of things to come, mineralwise. We have no crystal ball and if we possessed one we could claim no expertness in its use. In the first place no one can tell the future status of man. No one has any way of knowing to what extent peace will prevail, nor to what extent changes may occur in national sovereignties or forms of government or in international relationships. So future man is an uncertainty. Nor can we predict new developments that may result in significant changes in man's status or in the mineral industry or both. If, for example, this chapter had been written in the middle 1930's, nearly everything that has happened since in the fields of atomic energy and space technology would have been missed. Yet what vast changes these I have made in the status of man! Also the changes in the mineral industry have been important. A writer would have been bold indeed had he prophesied that uranium would play such an important role. But we need not confine our foggy vision to these fields. The steep rise in the use of aluminum, titanium, and germanium reflects the unpredictable in what may be thought of as the more normal pursuits. This should not discourage one from using the past and currently observable trends as bases for limited predictions. To do this, however, it is desirable to make certain assumptions about man's status without pretense that these assumptions have a high probability of fulfillment: 1. Only minor changes will occur in the geographical boundaries of the nations of the world. 2. World War III will not take place in the near future. 3. As a consequence of (2), man will not destroy himself by wanton use of atomic weapons. 4. Disarmament will take place, if at all, gradually rather than all at one time. Under the above assumptions the world will enjoy a period of relative peace even though the status may be one of an armed truce. The assump-

Jan 1, 1964

By Elmer W. Pehrson

Minerals have played a prominent role in the affairs of man and nations since time immemorial but with the advent of the industrial revolution, expanding use of the products of the mineral kingdom became synonymous with the material progress of mankind. Individuals and business groups have recognized this fact so have been aggressive in searching for and utilizing mineral resources, with notable success. Indeed, their achievements are primarily responsible for the present Machine Age. On the other hand, until recently the body politic has failed to grasp fully the essentiality of minerals although, at times, access to mineral supplies has been an important factor in the political maneuvers of nations. This chapter is concerned primarily with the broader political and economic relationships of mineral resources to the world economy, and with the internal and external actions of nations in the field of minerals. Many factors that condition the mineral economy of regions and the world as a whole, influence the internal and external affairs of individual nations. The more important of these are: 1. The nature of man's dependence on minerals. 2. The problems resulting from the unique characteristics of mineral occurrence. 3. Geopolitical concepts. 4. Minerals and world power. Actions of individual nations affecting their mineral economy seek two basic objectives : 1. Attainment and maintenance of prosperity. 2. Military security. Other objectives may be cited but on careful analysis they become integral parts or extreme phases of the two points noted above. For example, the twentieth century aggressions of the USSR, Germany, Italy, and Japan might be considered as direct bids for world power but they also can be interpreted as exaggerated or mistaken efforts toward military security and peacetime prosperity. Similarly, trade barriers, nationalization of industries, foreign exchange manipulations, taxation, monopolistic prac-

Jan 1, 1959

By Elmer W. Pehrson

Minerals have played a prominent role in the affairs of man and nations since time immemorial but with the advent of the industrial revolution, expanding use of the products of the mineral kingdom became synonymous with the material progress of mankind. Individuals and business groups have recognized this fact so have been aggressive in searching for and utilizing mineral resources, with notable success. Indeed, their achievements are primarily responsible for the present Machine Age. On the other hand, until recently the body politic has failed to grasp fully the essentiality of minerals although, at times, access to mineral supplies has been an important factor in the political maneuvers of nations. This chapter is concerned primarily with the broader political and economic relationships of mineral resources to the world economy, and with the internal and external actions of nations in the field of minerals. Many factors that condition the mineral economy of regions and the world as a whole, influence the internal and external affairs of individual nations. The more important of these are: 1. The nature of man's dependence on minerals. 2. The problems resulting from the unique characteristics of mineral occurrence. 3. Geopolitical concepts. 4. Minerals and world power. Actions of individual nations affecting their mineral economy seek two basic objectives: 1. Attainment and maintenance of prosperity. 2. Military security. Other objectives may be cited but on careful analysis they become integral parts or extreme phases of the two points noted above. For example, the twentieth century aggressions of the USSR, Germany, Italy, and Japan might be considered as direct bids for world power but they also can be interpreted as exaggerated or mistaken efforts toward military security and peacetime prosperity. Similarly, trade barriers, nationalization of industries, foreign exchange manipulations, taxation, monopolistic prac-

Jan 1, 1964

By RAY LYMAN WILBUR

SINCE boyhood I have had a keen interest in mining engineering. To see the prospector with his pack outfit and his pan, followed by the assayer and the trained engineer, has always had -something of the lure of romance for me. It is appropriate that the American Institute of Mining and Metallurgical Engineers should hold a general meeting in California, since this State has long been a home of mining engineering. Here, after the early open methods of mining, it has been necessary for the universities to train men in geology and mining, so that the earth could be penetrated and the rich ledges opened. In the eighty years in which the mines of California have been offering experience to the miners of the world, we have seen mining engineering evolve from a comparatively simple art, covered largely by rule of thumb, into a complex group of specialties, each utilizing the very latest discoveries in the various fields of physical sciences. Mining, too, has become a great business requiring large financial support and the most careful handling. Those mining engineers who have applied new processes in special fields have thus been able to give a wide-flung range to their activities in all parts of the world. The hand of nature in distributing minerals over the surface of the earth has compelled the mining engineer to become a modern pioneer, facing the heat of the tropics as well as the frozen regions of the north. There has been a marked cosmopolitan aspect to mining engineering, since the engineer had to go wherever the prospector discovered favorable leads. This has meant dealing with the harshest of conditions, the handling of labor of all sorts, the control of sanitary conditions, and relations to all forms of transportation. Naturally this has called on some of the very best minds in all countries to unlock the stores of hidden wealth. To make them available for civilization has been the job of the mining engineer.

Jan 1, 1929