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By W. H. Durrell

DISCOVERY of large iron ore deposits in New Quebec and Labrador is, undoubtedly, one of the outstanding mining events of the twentieth century. To give an idea of size, the present concession is almost equivalent to a strip a mile wide around the earth at the equator. Importance of this iron ore area can best be appreciated by comparison to the famous Mesabi Range. On Mesabi, the area of favorable rock is 110 miles long and from 1 to 5 miles wide, with a, productive zone about 70 miles long. On the con- cessions the area of favorable rock in the Labrador Trough is 225 miles long and from 10 to 60 miles wide. In Quebec-Labrador, exploration already discloses that the productive zone is 90 miles long, with good chances of being extended at both ends. The Mesabi is covered generally by thick over- burden, and the iron ore deposits were found by T- test-pitting and systematic test-drilling. In Labrador and Quebec, most ore has been developed from a few surface deposits, and when it is considered that at least 95 pct of the area is covered by over- burden, and that there remains thousands of square miles of favorable territory still to be explored, it can be seen that the possibilities for developing additional ore are tremendous.

Jan 4, 1954

By E. P. Shea

The Anaconda Co.'s Geological Department at Butte, Mont., was started early in the Company's history because of litigation involving vein ownership and extralateral rights. The problems, some of which were resolved in courts, were many because of the large number of veins and lode locations. Defensive action was required to prove ownership and protect against illegal exploitation of the downward and extra-lateral extensions of the ore bodies. In many cases it was necessary to define the outcrop of the vein and to show that its apex was within the boundaries of the lode claim. Exhibits illustrating geology were needed to present the cases clearly, and these could be made only after careful inspection and mapping of the underground workings by competent geologists. Also, The Anaconda Co. was one of the first companies to recognize the worth of skilled mining geologists and the value of accurate records in the search for new ore. The department was organized in 1900 by H. V. Winchell who, with D. W. Brunton, worked out the methods. Reno Sales was Chief Geologist from 1906 until 1948 when he was succeeded by V. D. Perry, the present Chief Geologist. Under their direction, F. A. Linforth, M. H. Gidel, C. H. Steele, E. P. Shea, C. C. Goddard, Jr., and W. A. O'Brien enlarged the scope of the work and improved the technique.

Jan 3, 1961

By J. E. Lawver, J. L. Wright, H. R. Kokat

Mesabi semitaconite and oxidized taconite ores that cannot be concentrated by froth flotation can be rendered amenable to flotation through partial concentration in a high-in tensity wet magnetic separator. Since 1964, a method for accomplishing this precon-centration has been under development at the Minnesota Mines Experiment Station, where several hundred tons of ore have been successfully processed. This paper is an analysis of the performance of the separators used at the Station. At present the United States is producing about 85 million tons of iron ore a year, and nearly 55 million tons of this comes from Minnesota. Nearly half of Minnesota's production is in the form of magnetite taconite pellets —the remainder being wash ore and gravity concentrates. As the demands of the blast furnace operators become more stringent - and they are becoming more so yearly — these demands are met by improved iron ore beneficiation technology. Furthermore, there is no doubt that as magnetite taconite, gravity ores, and wash ores are exhausted, new processes will be developed to produce a product comparable to magnetite taconite pellets from Minnesota's vast reserves of oxidized taconite and semitaconite. The magnetite taconite ores are rather easily bene-ficiated by conventional, low-intensity (500- to 1400-gauss) magnetic separators, followed, in some plants, by froth flotation of the magnetic concentrates.

Jan 1, 1969

By A. P. Herring, S. F. Ravitz

Manganese dioxide reacts with sulfur dioxide solution in the absence of oxygen to form manganous ion and dithionate ion, together with a small amount of sulfate ion. The effects of SO, concentration, hydrogen ion concentration, stirring speed, and temperature on the rate of the reaction were studied. If it is assumed that undissociated SO2 molecules react rapidly with MnO, at active surface sites and that bisulfite ions react slowly, an equation can be derived that satisfactorily represents the observed reaction rates. For solutions in which the reaction with undissociated SO2 predominates, reaction rates and activation energies estimated from diffusion theory agree well with those found experimentally. Manganese dioxide dissolves readily in aqueous solutions of sulfur dioxide. The nature of the dissolution reaction was first investigated by Gay-Lussac and welter1 in 1819; they identified a new oxysulfur radical, the dithionate ion, S2O6, as one of the reaction products. Since then, the reaction has become a standard method of preparing dithionates in the laboratory and one of the more promising methods of leaching manganese from low-grade ores. In the "dithionate process" developed by the U.S. Bureau of Mines2,3, manganese-dioxide ore is suspended in a solution of calcium dithionate and leached with gas containing sulfur dioxide. The manganese is dissolved and the sulfur dioxide is oxidized according to the reactions:

Jan 1, 1965

By J. Howard Boyce

INTRODUCTION The Tsumeb Mine is situated in the northern part of South West Africa, approximately 335 air miles north-east of the port of Walvis Bay on the Atlantic Coast, and 240 air miles north of Windhoek, the capital of South west Africa. The mine came into operation in the early 1900's and has operated continuously since then except during the two world warm and the depression years of the thirties, Tsumeb Corporation purchased the property in 1947, installed a new plat, and ham built a modern tom. In addition to the concentrator which began operations in 1948, a copper smelter was started in 1962 and a lead smelter in 1963, Tonnage of ore treated in the concentrator has varied through the years, reaching a maximum of 70,000 tons per month with a current mined tonnage of approximately 50,000 tons per month. Copper concentrates, lead concentrates and zinc concentrates are produced, and for a number of years the production of a germanium enriched concentrate was an important feature of the operation, Both copper and lead concentrates are smelted in Tsumeb, while the zinc concentrates are shipped overseas. Ore change, and the installation of the smelters in Tsumeb have necessitated modifications in the concentrator operation. This paper will describe current plant practice in some detail and will touch briefly on the techniques used from 1954 to

Jan 1, 1970

By George R. Mansfield

INTEREST in the reserves of phosphate rock in the United States and their proper conservation has recently been aroused by hearings held in different parts of the country by the "Joint Committee to investigate the adequacy and use of phosphate resources of the United States." This committee was appointed within a few days after a Presidential message to Congress on the same subject, dated May 20, 1938, and began to function almost immediately. Hearings were held in Washington, D. C., Pocatello, Ida., Wilson Dam, Ala., Knoxville, Tenn., and Lakeland, Fla. The resulting testimony, when published, comprised a volume of 1182 pages.1 At the earlier hearings held in Washington and Idaho the seeming disparity between the great reserves of the West and the smaller reserves in the East led to some suggestions as to the desirability of curtailing or even prohibiting the exportation of phosphate rock so that eastern producers, becoming alarmed, cooperated in making available for the use of the committee information hitherto closely guarded. This information has provided an opportunity for new studies by official agencies, for a restatement of the reserves of Florida and Tennessee, and for some modification of figures for the Western States. The writer, representing the Federal Geological Survey, was given free access to the Florida material and has prepared for publication a report,2 some features of which are summarized in this paper. The Tennessee material was studied by Dr. G. I. Whitlatch,3 of the Tennessee Division of Geology. Prof. J. Stewart Williams,4 of the Utah State Agricultural College at Logan, has published a recent study of the phosphate resources of Utah and the writer has given some further study to reserves of western phosphate from the viewpoint of including material of lower grade than that hitherto considered. Technologic advances in the phosphate industry must be credited with a large share in the expansion of reserves by making available for

Jan 1, 1940

By O’Brian. Daniel T.

Ore reserve determinations supporting property appraisals and economic analyses leading to investment decisions typically require many repetitive calculations. Computers have become well-accepted tools for accomplishing these computations, and are partly responsible for the development of new evaluation methods during the last decade. Excellent descriptions of manual ore reserve may be compared with current computer reserve methods1,2 in North America2 and South Africa3. A comparison indicates that computers are used in two cases: a) when a cost savings can be achieved by the simple conversion of a manual method to a computer processed equivalent, and b) when the quantity of data and ore reserve estimation purpose justifies adoption of a complex ore reserve computational method not feasible on a manual basis. Ore reserve computations essentially consist of using sample data and a mathematical method to arrive at an estimated geometry, tonnage, and grade for a mineral deposit. The mineral deposit is then subdivided, if necessary, into ore and waste components. This separation is based on economic factors which may be explicitly introduced in the computation or incorporated in a numerical cutoff grade4. Computer methods for accomplishing these tasks are presented in three papers. "The Use of Contour Surfaces as Predictive Models for Ore Values" discusses the requirements for a satisfactory value prediction model and the importance of considering auto -covariance. A weighted moving average method is described and compared to other mathematical surface development methods. In the second paper, "The Applications and Limitations of Computer Techniques in the Evaluation of Hypothermal Tin Lodes," particular problems encountered in estimating geometrically erratic economic deposits with a low valuable mineral content are documented. Economics and probabilistic concepts are introduced, allowing a comparison of risk and speculative value for a deposit. Economic considerations are integrated with ore estimation techniques in the third paper, "Method of Calculation of the Iron Ore Reserves in the Lorraine Deposit." The prediction model

Jan 1, 1969

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Mine Superintendent or Manager. Age 34, graduate mining engineer. Thirteen years' practical mining experience in Canada and United States holding responsible executive positions, mining engineer and mine superintendent. Experience in iron, gold, copper, and pyrite mining. Best references, can go anywhere but prefer location in Canada. At present engaged but desire change. Minimum salary $3600. A-2845. Manager or Superintendent for producing mine or new development. Institute member, 25 years' experience, mining, wet concentration, construction and examination. A-1173. Mining and Metallurgical Engineer. Technical graduate, 11 years' practical experience principally with copper mining, milling, smelting, and electrolytic refining, now holding an engineering executive position, wishes to change to place of more responsibility and opportunity. A-3785. Engineer with 11 years' experience in mining, civil, and industrial engineering, desires to become connected with a strong organization requiring services of thoroughly trained man. Graduated from University in 1909, now employed, having been with present organization nearly 7 years. Available about Sept. 15. A-4071. Metallurgical Engineer, age 31, married, A. M. and Ch. E.; 7 years' teaching and industrial experience, of which 3 ½ have been with electric furnaces. Desires position in investigative or executive work. Minimum salary $3000. A-4176.

Jan 9, 1919

By Lawrence Addicks

Discussion of the paper of LAWRENCE ADDICKS, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 104, August, 1915, pp. 1471 to 1484. L. D. RICKETTS, New York, N. Y.--In the Southwest we have stored up millions of tons of tailings in which the copper exists partly as sulphide and partly in an oxidized condition. Mr. Addicks' first paper suggests a, likely process for the treatment of such material. His second paper 1 deals with the recovery of copper from clear solutions of notable strength, and such solutions may come from the sulphating roast or direct from the leaching of completely oxidized copper ores of which vast deposits are known to exist. What strikes me particularly about the latter paper is the keen perception shown and the clear manner in which the writer has attacked the fundamental principles of the process. He calls your attention to the fact that ferrous sulphate is necessary in the electrolyte and is an ideal depolarizer; that sulphurous acid must be, used to reduce the ferric sulphate produced and thus prevent re-solution of copper at the cathode; that mechanical agitation in the cell, in order to bring the ferrous sulphate in contact with the anode and the copper in contact with the cathode, is essential to efficient work; that lead anodes are

Jan 12, 1915

By M. M. Leighton

INASMUCH as the arrangements for the preparation of the review of progress and new developments in the field of industrial minerals (non-metallics) were not made until early December, the writing of this review could not be completed in time to appear in this issue and will, therefore, appear in the February issue. However, we desire to call attention to the steadily increasing importance of this group of mineral substances. The recent book, "Industrial Minerals and Rocks," published by the Institute, lists 47 principal varieties of nonmetallic minerals to which may be added several more of lesser importance. Because of the wide variety of uses to which many of these industrial minerals are put, it is difficult to classify them into categories, but to mention a few examples which indicate the widespread industrial employment of these minerals and their products, one may cite: the use of limestone, gravel, sand, clay products, lime, cement, and gypsum in the construction industry; fluorspar, lime, salt, borax, and sulphur in the chemical industry; diamond, corundum, emery, garnet, flint, quartz sand, tripoli. and diatomite in the abrasive industry; fluorspar, limestone, and magnesite in the metallurgical industry; clay, feldspar, fluorspar, flint, chalk, and limestone in the ceramic industry; and asbestos, gypsum, mica, vermiculite, magnesia, diatomite, and rock wool in the heat, sound and elec-

Jan 1, 1940

THE Institute assembled in the Hall of the Boston Natural History Society on Tuesday evening. Dr. T. Sterry Hunt, of the Boston Institute of Technology, after a brief address of welcome to the Institute, read an introductory paper on the Geognostical History of the Metals. President Raymond responded to the welcome of Dr. Hunt. The following names were then presented to the Institute, with the recommendation of the Council, for election: Adams, J. M., . . . . . . Silver City, Idaho. Daggett, Ellsworth,. . . . . Salt Lake City, Utah. Geist, Alfred W., . . . . . Boston, Mass. Hays, Dr. S. Dana, . . . . . Boston, Mass. Heinrich, Oswald J., . . . . Midlothian, Va. Johnson, J., . . . . . . Braidwood, Ill. Leckie, Robert G., . . . . . Actonvale, Canada. Lyman, Edward, . . . . ' . Troy, N. Y. Maltby, William, . . . . . Braidwood, Ill. Nichols, Lyman, Jr., . . . . Bbton, Mass. Ordway, Prof. J. M., . . . . Boston, Muss. Rand, Theodore D , . . . . . Philadelphia, Pa. Richards, Prof. Robert H., . . . Boston, Mass. Roclrwell, Prof. Alfred P., . . . Boston, Mass. Roepper, Charles W ., . . . . Bethlehem, Pa. Schulz, A. von, . . . . . Central City, Colorado. Singer, William F., . . . . Pittsburgh, Pa. Spillsbury, E. G., . . . . . New York. Wells, Calvin, . . . . . . Pittsburgh, Pa. The session concluded with the reading and discussion of a paper, by Henry Engelmann, On the Mines and Ores of the Little Cottonwood Canyon, Utah. The second session was held on Wednesday morning, when the following papers were presented : On the Midlothian Coal Mines, by Oswald J. Heinrich. On the Probable Existence of Microscopic Diamonds in California, by Prof. Benjamin Silliman.

The following is an incomplete list of members and guests who' called at Institute headquarters during the period Mar. 10, 1918 to Apr. 10, 1918. W. Sinclair Brown, Lebong Donok, Sumatra. F. Laroque, Roodepoort, Transvaal. H. B. Catlin, Syracuse, N. Y. A. H. Means, Camp Upton. A. R. Chambers, New Glasgow, Nova Scotia. J. H. Miles, Nome, Alaska. W. M. Corse, Buffalo, N. 1 . Harvey S. Mudd, Washington, D. C. George C. Crossley, Toms River, N. J. Henry Noyes, Melbourne, Aust. F. A. Dalburg, Montoursville, Pa. C. L. Petzel, Camp Upton. Kuno Doerr, El Paso, Tex. J. L. Schueler, Peoria, I11. V. E. Edwards, Worcester, Mass. J. G. Scrugham, Reno, Nev. H. F. E. Gamm, Rutherford, N. J. Frank M. Smith, East Helena, Mont. J. W. Gerhard, St. Louis, Mo. W. G. Swart, Duluth, Minn. Julius H. Gillis, Sudbury, Ont., Canada. A. L. Sweetser, Boston, Mass. S. J. Gormly, Guayacan, Chile. W. N. Thayer, Cincinnati, Ohio. Fletcher Hamilton, San Francisco, Cal. Felix E. Wormser, Cornucopia, Ore. Dorsey A. Lyon, Washington,. D. C. John B. Arnold has opened offices at 606 Lyceum Bldg., Duluth, Minn. E. E. Barker, formerly mine superintendent with the Chile Exploration Company at Chuquicamata, Chile, has resigned his position to become superintendent of mines for the Cerro de Pasco Copper Corporation at Cerro de Pasco, Peru.

Jan 5, 1918

By Henry S. Poole

This field is geologically of much interest. It is small, hut with some seams of unusual thickness, the main one being as much as thirty-eight feet thick. The quality of the seams, as also of the associated beds of shale and sandstone, in several instances changes to a remarkable degree within short, distances. The strata dip at inclinations that carry the coal to depths of 3000 feet or more; heavy faults cut up the district, and the New Glasgow conglomerate, of disputed age, separates it from the Upper Carboniferous measures, in which no seams of workable thickness are known. This coal-field offers to the geologist much ground for study and peculation. The commercial value of the field is affected by its restricted area, the varied quality of its coal, and its advantageous position in the mainland, with railway connection and home markets, offset by the physical difficulties which make the cost of production high. It has been so long a habit with us to speak of our resources of coal as boundless, that any adverse comments, or insinuations that avoidable loss in working is a national loss, hare hitherto fallen on idle ears. While it is not my purpose to underrate the riches we do possess, yet I deem that no good end is served by echoing exaggerated estimates which encourage a national indifference to wasteful

Jan 1, 1886

By R. S. Archer

THE name molybdena was employed by Pliny to denote various substances resembling lead. Later this name was applied to galena-the naturally occurring sulfide of lead-or substances of similar appearance. By the middle of the eighteenth century, it was applied to graphite and to the mineral sulfide of molybdenum (MoS2) now called molybdenite. This confusion is quite understand- able inasmuch as these substances look and feel very much alike. In 1778, the Swedish chemist Scheele published a treatise in which he pointed out essential differences between graphite and molybdenite. On treatment with nitric acid, molybdenite, unlike graphite, produced a peculiar white earth with acidic properties which he called molybdic acid. Since the same mineral gave off sulfurous fumes on heating, he concluded that it was a sulfide of molybdenum. In 1790, there appeared an account of the isolation by P. J. Hjelm of the new element molybdenum, as a metallic powder, by heating the oxide with carbon. It was not until Bertelius conducted the necessary experiments, about 1818 to 1825, that the foundation of the chemistry of molybdenum was laid. The only recorded use of molybdenum during the first century after its isolation was as a chemical reagent, primarily for the determination of phosphorus. It was not until the last decade of the nineteenth century that the use of molybdenum in steel appears to have been investigated. A

Jan 1, 1953

By Richard B. Greenwalt

INTRODUCTION Direct reduction of iron ores has unquestionably become established as an important step in the worldwide steelmaking industry. The history of this development has been long and fraught with difficulty. In 1800, Champlain suggested the direct reduction concept using carbon and a shallow hearth vessel. Roughly 100 years later, Jones attempted a commercial process using carbon and producer gas in a rotary kiln. During the early years of this century, numerous attempts were made to start commercial direct reduction plants using such processes as Hoganas, Wiberg, Krupp-Renn, and others. Most of these were short lived, being abandoned due to a variety of technical and economical factors. Today, however, a new generation of direct reduction processes has emerged. We enter 1977 with at least 40 commercial plants in operation using 15 processes in 14 countries. These plants have combined total annual capacity of roughly 10 million tonnes of direct reduced product. Many articles have been written, and projections made, concerning the future growth potential for direct reduction. As is al- ways the case with projections, the numbers vary, but the outlook does not. Anyone who participated in the years of effort that have gone into this field of endeavor should be excited and justly rewarded by noting the shape of the curve in Figure 1.

Jan 1, 1977

By C. D. Tedmon, D. P. Ferriss

THE yield stress, o of low-carbon steel has been shown to vary with the average grain diameter, d, according to the relation1-3 where o is taken to be the lower yield-point stress Of is the friction stress on an unlocked dislocation, and ky is a constant. The interpretation2,4 of ky in terms of dislocation theory relates this constant to the stress to unlock a source across a grain boundary. cottrel14 predicted that ky would increase with decreasing temperature. This was observed to be the case by Adams and coworkers5 in their investigation of niobium (columbium). However, petch6 and Backofen: both working with low-carbon steel, found ky insensitive to temperature. In his work with high-purity niobium, Johnson' found ky equal to zero. Evansg showed that k, was essentially zero for niobium containing nitrogen in an appreciable concentration range. The present experiments were designed to check this apparent anomaly in the value of ky in another Group V metal. Yield points were determined as a function of grain size at several temperatures for tantalum and a tantalum-tungsten alloy. The material used was double are-melted tantalum and a double are-melted alloy of 90 pct Ta and 10 pct tungsten (by weight), both obtained as unannealed, swaged rod. The impurity content of the materials is given in Table I. The tantalum was annealed at 1325"C. in a vacuum resistance furnace using a tantalum boat. The alloy was similarly annealed at 1660°C. Annealing times varied from 15 min to 2 hr, depending on the desired grain size. Nominal pressure in the furnace was 3 X 10~4 mm of Kg. Metallographic examination showed that the annealing treatment produced grain sizes ranging frorn 0.021 to 0.200 mm in the tantalum, and 0.060 to 0.160 mm in the alloy. Tensile bars were made by centerless grinding the annealed specimen;, and then electropolishing to remove all grinding marks. The specimens were than pulled :it 2 1/2 pct per rnin in an Instron testing machine. The tantalum specimens were tested at 77", 195", and 300°K. The alloy was tested at 300°K only. All specimens exhibited a yield-point phenomenon at all temperatures. Typical load-elongation curves at the three test temperatures are shown in Fig. 1. The lower yield stress is plotted as a function of (grain size) in Figs. 2 and 3 for tantalum and the 90 pct Ta-10 pct W alloy, respectfully. The position and slope of the curves was determined by least-

Jan 1, 1962

By Charles Y. Clayton

THE general public does not know that there is such a thing as metallurgy and it is very seldom that you see the word metallurgy in print except in technical magazines. Perhaps it is more to the front now than in former years; the Dee. 30, 1929, issue of Time mentioned under the heading of "Science7' certain new achievements in metallurgy, which may be cited as a rare instance of the use of the word in anything but the technical press. Too often the part the metallurgist plays in the advancement of the different branches of engineering is overlooked. To say that the public does not know there is such a profession as metallurgical engineering seems to be a bold statement, but had there beep time a questionnaire could have proved this beyond doubt. Suppose a carefully-planned questionnaire had been sent to all high school students asking them, among other questions, to list the different branches of engineering, I believe that the several professions would have been listed in this manner: (1) Electrical engineering; (2) mechanical; (3) civil, and (4)' mining. One in each hundred might have listed metallurgy as an engineering profession. Even the Society for the Promotion of Engineering Education in its Bulletin No. 10-"Investigation of Engineering Education" lists Civil, Mining, Mechanical, Electrical, and Chemical, leaving out Metallurgical Engineering.

Jan 1, 1930

Jan 1, 1977

By B. Fagerberg, P. H. Fahlstrom

Crushing and grinding practice in Sweden follows closely the international pattern. Certain special circumstances, however, have had an influence on its development. Most mines are worked underground. These mines are either quite small or very large. Sulfide ores are commonly treated by custom milling and, apart from the cement industry, the rock species treated are hard and abrasive. Another important factor is the increasingly strict requirements placed on the mechanical condition of different products, especially lump ores and coarse iron-ore concentrates. Increasing requirements are being placed on the concentrate grade to suit the new steel processes. As a result, iron ore beneficiation has expanded considerably for the production of fine pelletizing concentrates. This applies especially to magnetite ores in the intermediate phosphorus range 0.1-1% P. In 1969, about 5.5 million tons of pellets will be manufactured. It should be pointed out, however, that fairly large quantities of coarse products are still being made at mills where the right conditions are available. Crushing and grinding is also of great importance in the production of rich concentrates at high recovery from sulfide ores. In fact, a large part of the development work on the concentration of sulfide ores has been devoted to the crushing and grinding processes. Boliden has played an important role in this connection.

Jan 10, 1969

By Franklin Bache

There seems to be in the public mind, and even in the minds of some coal-operators not experienced in mines subject to dust-explosions, a feeling that there has been somet-hing mysterious at the bottom of a number of recent American colliery-exploaions. It has been declared in cases of accidents in mines regarded as particularly well equipped, in which every preventive precaution was said to have been taken, that the explosions were incomprehensible, and resulted from causes beyond the present knowledge of the practical coal-operator. But it is safe to say that no explosion has taken place which could not be explained by reasons well understood by most operators. The U. S. Geological Survey Testing Laboratory, recently inaugurated at Pittsburg for the reported purpose of investigating scientifically the matter of explosions in mines, will discover no new explanation of explosions. It can, however, co-ordinate the previous investigations of similar boards in England and on the Continent; and it may do a vast amount of good by promulgating widely, and in a form comprehensible to the most unlettered miner, certain facts and obvious deductions that cannot but have an effect in reducing the number and extent of the mine-disasters which, in the last few years, have been so terrible in frequency and magnitude.

Jan 1, 1910