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By Henry S. Washington

I. INTRODUCTION. DURING the last twenty years or so the chemical investigation of rocks has made great advances, and it is now generally recognized that a knowledge of the chemical composition is as essential as that of the texture or mineral composition-if not more so-for the proper classification of rocks and study of their origin and relationships. Rock-analyses have vastly increased in numbers and, what is of greater importance, in quality. New and improved methods permit of greater accuracy than was possible in the early days, and the list of chemical constituents frequently determined has risen from the seven or eight of the greater part of the nineteenth century to twenty or more. Indeed, rock-analyses with determinations of so many constituents are now commonly made by the chemists of the United States and Australia, while in Germany, Great Britain, France, and Italy the rarer constituents are determined more frequently than formerly. As a consequence of this modern, accurate work, it has been discovered that some elements which were formerly supposed to be rare are of wide-spread occurrence and are often present in considerable amount. The fact is further being developed that the elements tend to show certain relations of occurrence or abundance in connection with each other. This is a fact which is applicable to the rarer elements, and which also finds a broad geological and petrological expression in the recognition of petrographic provinces. We are beginning to obtain some definite, though as yet rudimentary, knowledge of the distribution of the elements among igneous rocks. Some of the results along these lines obtained by study of the vast accumulation of analytical data now available are well known to petrologists, while others do not seem to be so gener-

Sep 1, 1908

By Bruce A. Kennedy

This is an opportune time to examine the disposition of practical rock mechanics in the mining industry. The rock mechanics world has put on steam with publication of a number of books and the organization of a large number of symposia and teaching seminars. SME has just published Stability ill Open Pit Mining. proceedings of a conference held In November 1970 in Vancouver, R.C. R book entitled Planning Open Pit Mines covering the entire range of open pit mining with emphasis on slope stability has just been published by the South African Institute of Mining and Metallurgy. The Thirteenth Symposium on Rock Mechanics was held at the University of Illinois. Urbana-Champaign, during the last week of August. The University of British Columbia's Division of Continuing Education is holding a symposium and specialty seminars on stability in open pit mining during the first week in November. A tremendous planning effort has started to organize the Tl3ii.d Congress of the International Society of Rock Mechanics in Denver in 1974. This meeting is held every four years in the country of origin of the president of the Society. This third congress comes to the U.S.A. with Leonard Obert of the 17. S Bureau of Mines as president of the Society. The previous two were held in Lisbon. Portugal and Belgrade. Yugoslavia.

Jan 1, 1971

By E. D. Gardner

FIFTY years ago the Utah Copper enterprise at Bingham was just getting under way. An epic in metal mining was in the making. Throughout the West the bonanza deposits were approaching exhaustion and most ore still went direct to smelter. But concentrators were shortly to be constructed for treating milling grade ores, and most important, the pilot plant for the Utah Copper enterprise was being built that year at the mouth of Bingham Canyon. The same decade was to see development at the Inspiration mine in Arizona of the most important new mining method for 50 years to come—undercut block caving. Although the average grade of ore being mined has been declining for 50 years, and wage rates and prices of supplies have been greatly increased, the mining industry has continued to grow and to prosper. Technology has advanced to a point where minerals can be mined under the most severe conditions. The hardest rock can be drilled and broken and the heaviest ground handled. Large or small, an ore-body can be mined successfully, at any desired rate of production. It is possible to pump great volumes of water and to ventilate the most extensive workings; air conditioning has made practicable the mining of ore where the rock temperatures are beyond those that can be borne by man. Mining today in the U. S. is a huge earth-moving operation. In 1953 nearly 2 billion tons of material were mined for direct use or for processing. Stripping at open-cut mines totaled about 1.7 billion cu yd. Table I gives relative tonnages of the branches of the mineral industry in 1953. In addition to the solid materials moved, 350 million tons of petroleum and 340,000 tons of gas were produced in 1953. Fifteen million tons of salt and 5 million tons of liquid sulphur were pumped from wells. An appreciable amount of copper was recovered by leaching old mine workings and dumps. Total value of minerals produced in 1953 was $14.4 billion: oil and gas $7.6 billion, coal $2.6 billion, nonmetallics $2.4 billion, and metals $1.8 billion. Formidable problems face some branches of the industry today, especially pertaining to increased output tons per manshift. The time has come when these problems should be reappraised. With current wage rates, the industry no longer can afford to pay men to do manual labor. It should be recognized, also, that the miner is a skilled worker; efforts to promote the dignity of his calling and his pride of accomplishment have yielded beneficial results. Mineral deposits occur under widely varying conditions. In most instances the degree of support needed by the roof and walls is the deciding factor in selection of an underground mining method. The degree of support needed, in turn, is governed by natural physical characteristics of the ore and its enclosing rocks. Mine operators, of course, learn to judge ground by observation, and an experienced mine boss generally can anticipate what will happen following any given mining operation. A more scientific approach, however, would be advantageous in most cases. More should be known about the strength of the ore and the enclosing rocks, more about stresses set up in the ground when ore is removed, and more about the mechanics of moving ground. Better understanding would work both ways: first, favorable rock conditions could be fully utilized for more efficient mining, and second, hazards of rock falls could be minimized, loss of ore in mining reduced, and expenses caused by ground pressures and subsidence lowered. In general, mining comprises breaking the ore or rock in place, supporting the mine workings, and transporting the ore to the surface. This latter is a materials handling problem. Ventilation, of course, must be provided, and the mines must be kept free of water. Development work at some places is the most important cost item in extracting ore. Drilling and blasting remain the usual practice for breaking ore or rock from place except, of course, at block-caving mines. The drilling and blasting practice at a mine must fit the mining method. In laying out mining procedures attention is being given to

Jan 1, 1956

By Harvey N. Davis

MUCH has been written and said during the last twenty years about the place of the engineer in modern life, about the fundamental role that he plays both in developing and in maintaining the material foundations of modern civilization, about the advantages, and also the dangers, of the machine age that he has inaugurated, about the Frankenstein problems that he has unconcernedly foisted upon a generation utterly unable to cope with them, and about the obligation that rests upon him to stop inventing machines and turn his almost legendary energy and skill to inventing institutions that will constitute a solution of the problems he has raised, and contrariwise about his utter inability to offer wise or useful counsel in fields outside the narrow boundaries of his technical training.

Jan 1, 1938

By Albert Sauveur

SOME writers believe that when austenite transforms completely into pearlite on slow cooling through the thermal critical range, such transformation does not imply the formation of any of the so-called transition constituents: martensite, troostite and sorbite. Might it not be claimed with as much justification that when water freezes it does so suddenly, solid ice being obtained without passing through the intermediate stages of ice and water? Obviously, regardless of the speed of solidification, this would be erroneous. Before reaching the completed solid condition, this must of necessity pass through an unbroken series of stages when the system consists of mixtures of water and of ice, the former decreasing and the latter increasing in amount. Are not these "transition" stages in the freezing of water similar to the transition stages occurring in the transformation of austenite into pearlite? To clarify, let us consider in Fig. 1 the mechanism of the transformation of eutectoid steel from its austenitic to its pearlitic condition as it cools slowly through its thermal critical range. It is generally admitted that this transformation is the result of two distinct phenomena: (1) the allotropic change of gamma iron into alpha iron and (2) the crystallizing out of solution of the carbide Fe3C. Whether this crystallizing of Fe3C implies also its formation is immaterial for our purpose. In other words, whether it is the carbon in atomic dispersion which is present in gamma iron or molecules of Fe3C has no bearing upon the matter to be discussed. The transformation of gamma iron into alpha iron cannot take place suddenly. It must of necessity be progressive, regardless of the speed with which it may take place. At A, for instance, there would be present AB gamma iron and BC alpha iron. The distance MN does not refer to falling temperature, but to the passage of time. It may be assumed that the transformation takes place at a constant temperature (the Ar321 point). In a similar way, the crystallization of Fe3C out of the austenite solid solution must be progressive as depicted between M and N. At A there would be present AB gamma iron, BC alpha iron, CD carbon dissolved in gamma and in alpha iron and DE Fe3C. This condition may be described according to individual preference as martensite or troostite. To sum up, can the metal pass from condition

Jan 1, 1931

By Edmund C. Pechin

THE iron trade of America seems on the point of a new departure. After years of struggling against heavy odds, patient endurance in periods of depression and loss, fears and hopes alternating as failure or success seemed to be the penalty or reward ; wanting in sufficient capital, embarrassed by reason of imperfect knowledge and lack of skilled labor, confronted by a powerful foe-every doubt has at last vanished, physical and mechanical difficulties have been largely over-come, capital has become more abundant and remunerative, the excellence of our product has been everywhere established, and the peculiarities of American character-pluck, energy, and perseverance -have at last placed the trade upon a foundation so broad and stable that upon it we begin to erect the structure of a world-wide business. Concerning the future of the iron trade in the United States there can be but little doubt. The growing scarcity and constantly increasing cost of raw material in Great Britain, their loss of labor by emigration, the social disturbances among the working-classes, assuming a more threatening attitude on each new outbreak ; the rapidly decreasing value of money, in consequence of the enormous production of gold and silver, combine to forbid any return to former prices, and indicate that a point has been reached beyond which any marked increase of production is improbable. The same causes are operating to a greater or lesser extent upon the Continent. In the meanwhile the growing wants of humanity are rapidly outstripping these sources of supply. In addition to the steadily increasing foreign and home demand, we find, the world over, the most intense activity everywhere displayed in enterprises requiring

Jan 1, 1873

By Ralph H. Sweetser

IN the recent world-wide deflation of commodity prices the coal industry, including both anthracite and bituminous coal, had reached a level where the actual delivered market prices received by the operators were usually less than the cost of production. Many steel companies and public utilities, operating their own "captive" mines, could have bought coal during the past three years for less money than the true cost of coal produced at their own properties. Competition within the coal industry itself was cruel to the point of profitless operation, and the competition of other forms of fuel was bearing heavily on the coal producers. They were thus forced into methods of production and utilization that they had hitherto ignored; there had been almost complete absence of any appreciation (by the bituminous operators especially) of the necessity of real research work in finding better methods of preparing coal for specific uses, and in finding new and profitable uses for different kinds and grades of coal.

Jan 1, 1933

By WALTER M. DAKE

GENERALY speaking, the bituminous coal mines of the country are being operated at a loss. To purchasers of the necessary commodity, a statement of this character may have the sound of a far fetched propagandist cry; but to the coal producer who lives in the hope of an up-turn in the almost stationary market price of his product, while inking in red his monthly operating balances, it carries the ringing sound of truth.

Jan 1, 1925

By Arthur R. Still, Paul Gilmour

The ore deposit of the Iron King mine occurs in a group of steeply-dipping metamorphosed eugeosynclinal volcanic and sedimentary rocks of Precambrian age. Within this sequence, the ore deposit lies at the contact of a unit made up of rhyolitic tuff and interbedded andesite and a structurally underlying series consisting of andesitic tuffs, minor rhyolitic tuffs, and argillaceous sediments. Field evidence suggests that these rocks have been overturned. The ore deposit is made up of a series of overlapping, conformable or bodies consisting of massive pyrite and associated lenses of massive quartz. These contain recoverable amounts of gold, silver, lead, zinc, and copper. A parallel zone of copper mineralization occurs within the hanging-wall rocks. The deposit is considered to belong to a large and important group characterized by mineralogical composition and the lithology and structural type of the host rocks. Evidence regarding the origin of the deposit is reviewed, and it is concluded that the ore bodies were formed through the agency of volcanic hot springs on, or near, a submarine surface of deposition

Jan 1, 1968

By P. E. Queneau

This study confines itself to an examination of the two million square miles of the northern hemisphere which the geographer defines as the terrestrial Arctic, a land region in which the mean temperature of the warmest month is below 50°F-in effect, the area lying north of the tree line. The engineering and human problems there are of a different order of magnitude than is generally true of the sub-Arctic. Whether in Dawson Creek or Matanuska, in Mo i Rana or Skelleftea such problems are of the same general order as in Hibbing or Noranda. The same is not true in Kong Oscar's Fjord or Lancaster Sound.

Jan 7, 1961

By Henry S. Washington

I. INTRODUCTION. DURING the last twenty years or so the chemical investigation of rocks has made great advances, and it is now generally recognized that a knowledge of the chemical composition is as essential as that of the texture or mineral composition-if not more so-for the proper classification of rocks and study of their origin and relationships. Rock-analyses have vastly increased in number and, what is of greater importance, in quality. New and improved methods permit of greater accuracy than was possible in the early days, and the list of chemical constituents frequently determined has risen from the seven or eight of the greater part of the nineteenth century, to twenty or more. Indeed, rock-analyses with determinations of so many constituents ire now commonly made by the chemists of the United States and Australia, while in Germany, Great Britain, France, and Italy the rarer constituents are determined more frequently-than formerly. As a consequence of this modern, accurate work, it has been discovered that some elements which were formerly supposed to be rare are of wide-spread occurrence and are often present in considerable amount. The fact is further being developed that the elements tend to show certain relations of occurrence or abundance in connection with each other. This is a fact which is applicable to the rarer elements, and which also finds a broad geological and petrological expression in the recognition of petrographic provinces. We are beginning to obtain some definite, though as yet rudimentary, knowledge of the distribution of the elements among igneous rocks. Some of the results along these lines obtained by study of the vast accumulation of analytical data now available are well known to petrologists, while others do not seem to be so gener-

Jan 1, 1913

By Frank H. Skelding

Still the world's largest producer, consumer and importer/exporter of minerals, the United States has, in recent years, become more and more aware of the many diverse forces that increasingly affect its ability to maintain free access to and trade in minerals, both domestically and abroad. The nation's growing dependence upon foreign sources of minerals in the face of mounting competition is causing many changes, not only in the mineral industries, but in national attitudes and policies as well. This paper examines the position of the United States in the world mineral economy relative to the significant trends that have and are developing. It attempts to define and evaluate the major present and future impact of these trends and to anticipate the probable effects upon the U.S. and its mineral economy.

Jan 1, 1976

By J. B. Bassett, E. S. Rowland

INTRODUCTION THE experimental work reported herein was inspired by the publication of a paper by Grange and Stewart,1 in which it was suggested that at low chromium contents the effect of this element on the [M,] point was greater than at higher chromium contents. It was argued that, if a small increase of chromium in solution in austenite caused a sharp lowering of the [M,] point, it might lead to an explanation of occasional unsolved stress cracking of SAE 52100 during heat treatment. Commercial hardening is carried out at temperatures of incomplete solution, leaving carbides available to enrich the austenite during any inadvertent increase in temperature. Such enrichment of the austenite in chromium content would lower the [ M,] point nearer room temperature where cracking is more likely to occur. Accordingly, it was decided to investigate the effect of chromium, in quantities between o and 2 pct, on the[ M,] point of commercial steels. Fig I summarizes the data available on chromium steels. For purposes of comparison, the [M, ] temperature values were corrected by means of the Grange and Stewart formula§ to (I) Hypoeutectoid compositions: 0.50 pct carbon and 0.80 pct manganese (2) Hypereutectoid compositions: 1.00 pct carbon and 0.35 pct manganese. Only the steels having compositions reasonably close to these corrected values were included, because large adjustments inevitably introduce increased errors such as are experienced in using the formula. The straight lines of Fig I were drawn by the authors. These data obviously do not settle the question of the effect of chromium on the [M,] point, particularly at low chromium contents. While it is fairly well established that chromium causes the [M,] to be lowered when present in quantities of I pct or more, Grange and Stewart1 have suggested that in small amounts (less than I. pct) it is more effective in lowering the[ M,] point, while Klier and Troiano2 have suggested that in small amounts it is less effective in lowering the []M,] point. Payson and Savage3 concur with Klier and Troiano and further suggest that the effect is not linear at these concentrations. Rose and Fischer4 report that small amounts of chromium actually raise the-[M,] point of a 0.20 carbon steel. MATERIAL Two series of 35 lb induction heats were melted for this work, the analyses of which are given in Table I. One series was aimed at 0.50 pct carbon and 0.80 pct manganese with chromium additions in 0.25 pct increments from o to 1.5 pct with a single heat at 2.0 pct Cr. This series was considered necessary because the commercial heat treatment of SAE 52100 does not generally introduce more than about 0.60 pct carbon in solution in the austenite. The high

Jan 1, 1948

By E. P. Bucklen, L. J. Prelaz, J. R. Lucas

Today, the future of the coal industry is extremely bright because coal can be produced at a cost which makes it competitive with other energy sources. However, the industry has been forewarned that further cost reductions must be made if it expects to remain a serious contender in the growing energy market. Surface as well as underground operations must be improved. The very same elements which affected production a few years ago still exist today and will continue to be present in the future. Improvements in production mining equipment, mining methods and auxiliary equipment have resulted in reduced costs over the past few years. Efforts must be continued toward further reducing costs in areas which have been previously improved and new areas should be investigated for possible improvements. Therefore, new techniques must be developed which will enable the industry to augment its current efforts in reducing the cost of mining. The logical place to begin evaluating the factors affecting production and cost is in the immediate face area where a substantial part of the total cost of mining is incurred. The coal industry stands to gain much through the development of new techniques for analyzing the numerous variables affecting production and by establishing methods for eliminating or minimizing the adverse effect of those variables which can be controlled. Intuition and trial-and-error methods have been the standard means used to resolve many of the factors which influence production. As a result, many elements are overlooked or ignored because their effects on production are not pronounced and cannot be readily resolved.

Jan 3, 1965

By G. E. Karantzavelos

Although jigging has been the subject of extensive studies, evaluation of the effect of various jigging factors on the efficiency of separation has been less comprehensive. The basic factors that affect jigging separation are reviewed, a mathematical model describing jigging kinetics is presented, and attention is focussed on the mechanisms of the stratification process. The parameters of the kinetic model (the Wei- bull distribution function) are redefined in a gravity concentration technological sense, and their values are estimated for a wide range of jigging conditions. Several mathematical relationships (regression models) are also formulated which express the dependence of total time required for the complete stratifaction of mineral particles on the operating jigging variables.

Jan 1, 1984

By Thomas H. Sheehan

The purpose of this paper is to present an application of computer technology to assist the mineral company financial executive in assessing exchange risks. The paper is divided into five parts: Background, Translation Approaches, Theory, Empirical Validation, and Conclusion. BACKGROUND Exchange risk results from a change in the rate of exchange between a host and a home country's currencies. Legitimate reasons exist for changes in the currency exchange rates among countries in a world with over a hundred different currencies. These reasons include: different economic growth rates, social factors, cultural heritages, and political motivations. The problem of exchange rate changes are perennial and exist whether the world operates on exchange rates or floating exchange rate practices. The cause of the problem is trade and international payment imbalances. If one accepts the premise that exchange rates fluctuate over time, then the mineral company financial executive faces a continual process of reassessment of the impact of exchange rate changes on the financial worth of his company. (1) The mineral company financial executive prepares balance sheets and income statements that are audited by certified public account- ants annually for shareholders, bankers, and tax authorities. The financial executive translates assets and equities denominated in foreign currencies into domestic dollars, e.g., Japanese firms convert to Yen, French firms convert to Francs, and so on. When figures from foreign subsidiary operations are consolidated into the balance sheets of the parent corporation, estimates of the company's finan-

Jan 1, 1977

By R. S. Shrode, R. F. Bunting

Transportation is one of several important increments in the total market cost of most commodities. On a national average it has been reported that transportation accounts for about 25% of the total cost of a product at the market place. And industrial minerals are no exception. In fact, the proportionate cost frequently exceeds the 25% average. Further, it may actually determine the economic value of a deposit. Transportation possibly may be thought of as a specialized subject, of concern only to a traffic manager and of only nominal interest to the mining engineer, the geologist or other technically oriented member of a mineral producers' staff. However, in the industrial minerals field, interest is not commonly confined to exploration, development, production or marketing, but is in contrast an overlapping one. In a very real sense this broad area of interest in the total economics of the business is the specialty of the industrial minerals man. And transportation is a vital part of the total picture.

Jan 1, 1970

By JOHN JERMAIN

In my opinion, the explanation of the fuel-requirements involving the conception of heat available and necessary above a critical temperature, as advanced by Johnson 1 and elaborated by Howe, Raymond and others,2 affords a theoretically correct basis for such an accounting. It is the purpose of this paper to set forth a first crude attempt to construct a formula which shall show quantitatively the relation between the various factors affecting fuel-economy, and afford a means of comparing the enormous amount of data on the fuel-consumption of various blast-furnaces, at various times and under various conditions of operation. I have also applied this formula to a large number. of individual cases, and have, by its means, compared the furnace-practice of several important iron-making districts. II. DERIVATION OF FORMULA FOR FUEL-REQUIREMENTS. The general expression for the fuel-requirements of the blast-furnace, which I believe to be theoretically correct as to form, is as follows Carbon per ton of iron = Heat per ton of iron necessary in hearth above Tc./Heat per pound of carbon available in hearth above Tc. XFactor of rate of driving. +Carbon dissolved by CO2 of flux. +Carbon dissolved incidental to reduction of ore. + Carbon dissolved in pig-iron. (NOTE.-Tc = critical temperature.) Since, according to Johnson's theory, fuel-economy is usually limited by heat available and necessary in the hearth, rather than by the total heat supplied and necessary, we may write Carbon needed in hearth = Hn/Ha in which Hn is the heat per ton of iron necessary in the hearth above some critical temperature, and Ha is the heat per pound of carbon available in the hearth above this same critical tem¬perature. 1 Trans., xxxvi., 454 (1906). 2 Trans, xxxvi., 792 to 798 (1906) ; Trans, xxxvii., 216 to 237 (1907).

May 1, 1911

By Robert L. Bates

On April 2 and 3, 1970, more than 100 geologists attended the Sixth Annual Forum on Geology of Industrial Minerals at Ann Arbor, Mich. After this brief appearance, the Forum apparently ceased to exist- but it didn't really, and another spring will see it again in action, in another corner of the country. The organization might be characterized as the country's largest permanent floating conference on the geology of industrial minerals. What is the Forum, where did it come from, and what is it up to? The idea originated in 1964 with a small group in the Department of Geology at Ohio State University, Columbus. This group felt that a forum was needed for the exchange of geologic information on industrial rocks and minerals. They envisioned an approach-which has subsequently been adhered to--that would be dominated neither by geological academics interested in theoretical problems nor by practical engineers concerned with processing large tonnages of rock. It was proposed to focus attention on the middle part of the spectrum, especially on practical problems of geological occurrence and how these problems affect extraction and use. In terms of the standard rock-products flow sheet, which starts with a truck unloading into the primary crusher beneath the words 'from quarry,' it was proposed to focus geological attention on what is beyond the primary crusher, out in the quarry.

Jan 1, 1970

By W. P. Sykes

SINCE Honda and Murakami1 in 1918 proposed their constitutional diagram of the carbon-free iron-tungsten system, considerable effort has been expended by several investigators in attempts to define more positively the structural features of the alloys. The existence of an intermediate phase corresponding to the formula Fe3W2 (68.7 per cent W) was proposed from evidence of a purely metallographic nature by one of the present authors2 in 1926. Since that time the identity of this phase has been confirmed by Arnfelt3 and by Takeda,4 both of whom employed X-ray methods as well as the microscope and the chemical analysis of isolated microconstituents. According to Arnfelt, Fe3W2, as crystallized from the iron-rich melts at a temperature above 1450'C., contains by analysis 68.7 per cent W. The lattice of this phase is characterized by trigonal symmetry. Arnfelt, moreover, proposed a second intermediate phase formed at some temperature between 1450° and 1000° C. by a peritectoid reaction involving Fe3W2 and the iron-rich solid solution. A melt containing 25 per cent W was cooled to 1000° C. and heated for. 100 hr. The precipitated tungsten-rich constituent was separated and found by analysis to contain 62.6 per cent W. This composition agrees closely with that represented by the formula Fe2W (62.2 per cent W). Diffraction patterns from the concentrated precipitate showed a hexagonal unit cell. Takeda confirmed the data of Arnfelt regarding Fe3W2 but was unable to detect Arnfelt's second intermediate phase. While Takeda. failed to describe in detail the treatments employed, he stated that in alloys containing 40 per cent W which were quenched after heating at various temperatures between 1200° and 1450° C., no evidence of the second phase (Fe2W) was observed either in the microstructure or in the diffraction patterns of isolated residues. He therefore considered the existence of this low-temperature hexagonal compound as disproved.

Jan 1, 1932