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By H. C. Fiedler

THE development of the cube-on-edge secondary re-crystallization texture in Si-Fe strip depends upon the ability of inclusions to restrain normal grain growth. This ability is determined by the number and size of inclusions, which, for a given composition, is controlled by the thermal history of the material during the prior processing.' It has been shown2 that increasing the silicon content decreases the solubility of sulfur, and it is the purpose of this note to show the consequences of this decreased solubility for secondary recrystallization. Heats were made as previously described and cast into graphite molds.' The compositions are shown in Table I. Slabs 1 in. thick were cut from the ingots and either hot-rolled from 1000°C in the as-cast condition or after one of the heat treatments described later. The processing to the final gage of 12 mils followed the previous procedure.' To avoid cracking, the 5.2 pct Si alloy was cold-rolled at 150" to 200°C rather than at room temperature. The percent cube-on-edge texture developed by isothermal heat treatments was determined by dividing the maximum torque measured on disk sam-

Jan 1, 1968

By R. E. Sinke

Demerara Bauxite Co. in British Guiana has come a long way in tackling the problem of stripping and removing overburden. When the company started mining in 1917, overburden was hand-loaded into carts pulled by donkeys. Since then it has been recognized that overburden removal is one of the greatest problems. Over the past years a great quantity of equipment has been purchased, discarded as it became obsolete, and replaced with better and cheaper tools. The policy has kept the company's overburden removal costs within reason. Accurate records of costs per cubic yard and cubic yards per hour per unit have been kept for many kinds of equipment. Walking draglines and hydraulicking equipment are the key approaches to the current operation, but shovels, tractor-drawn wagons, self-propelled rubber tired scrapers, and tractor-scrapers still have limited applications. Mackenzie, operational headquarters of the Demerara Bauxite Co. Ltd., is on the Demerara River, 65 miles from Georgetown, British Guiana. Ore treatment and ship loading facilities are at Mackenzie, head of navigation for ocean-going vessels and the mines are located 7 to 40 miles farther upstream.

Jan 4, 1955

By W. C. Peters

From the time of its beginning in the mid-19th century, the American barite industry has had its major development in the eastern and central states. Geologic and economic factors serve to maintain Arkansas, Missouri, and the Southern Appalachian states in the lead position. In earlier days, the major markets for barite were in paint, chemical, and glass manufacturing, and the favored deposits were those which were close to eastern industrial areas; furthermore, the eastern deposits were cheaply mined and required little or no beneficiation. In the last few decades, the use of barite as a weighting medium for muds in rotary oil well drilling has caused a great expansion in the industry, but the marketing picture is still centered outside of the western states-now on the Gulf Coast area where high pressures are common in oil wells. Low cost imported barite, readily available on the East Coast and Gulf Coast, has always been a major marketing factor in the industry. The major barite producing state is Arkansas, with the industry centering about the Magnet Cove area. Missouri ranks second, with production mainly from residual deposits. Several Southestern states are actively producing from residual deposits.

Jan 9, 1958

By H. l. Burghoff

DURING the course of preparation of crystals of alpha brass for an investigation of their creep characteristics, a number of critically oriented crystals were produced. In each of these specimens, P0, the specimen axis, lay near some important crystallographic direction or on or near the border of two possible slip systems. Because of the unusual nature of their orientations, it was considered of interest to deform these speci-mens in simple tension and to study orientation changes and any unusual occurrences, different from what would be expected for specimens in which only one slip system had distinctly the highest maximum resolved shear stress. Choice of actual operating slip system in a crystal offering an immedi-ate possibility of two slip systems would be expected to be due to chance, defect, or some inhomogeneity. Even in an ideally perfect crystal so oriented, the natural oscillations of the atoms about their lattice positions would give rise to a condition wherein one slip system would be favored over the other at the critical shear stress. In the large, nonperfect crystals of the present investigation, slip on both systems, but in different portions of the specimen, might occasionally be expected.

Jan 1, 1940

Carlisle: This is April 19, 1961. My good friend Dave Irwin is sitting on the other side of the tape recorder. We are at Rose Dhu Island, Savannah, Ga. Now, let's begin with your first job, where and what was that? Irwin: I started out to Arizona, looking for a job and wound up in Morenci. The next morning I applied at the mine office and was put on as a sampler. I worked as a sampler and as an assistant to Frank Pelton, the geologist, for a year, after which I went back to New Haven to take my last year of postgraduate work. After getting my degree, I went back to the Southwest with W. Rowland Cox and Staff, supposedly as a geologist. Q: But that was not when he was with Spurr? Irwin: That was after he had left Spurr. Henry Smith was with the Spurr end of the outfit and I happened to drop into the W. Rowland Cox end. My first job with him was to do some work on a prospect above Metcalf, Ariz., and from there I would go out on short reconnaissance trips in Arizona, New Mexico and old Mexico.

Jan 6, 1964

By H. L. James

THIS paper presents the results and analysis of field trials of various magnetic instruments over anomalies ranging from 20 to 5000 gammas of vertical intensity. The following instruments were used: Askania vertical magnetometer, Wolfson vertical magnetometer (model M-I), Hotchkiss Superdips (used both parallel to and normal to the magnetic meridian, with several settings of the "sigma" angle), Lake Superior dip needle, and the dipping circle for measurements of inclination. The change in inclination over the measured anomalies ranged up to 4°; this caused pronounced changes in sensitivity of the Hotchkiss Superdip oriented parallel to the magnetic meridian. The variable sensitivity not only gives apparent displacement of crests of anomalies, particularly at high sensitivities, but also makes the data difficult or impossible to use in preparation of iso-anomaly maps. This weakness in field performance of the Superdip is shown to be eliminated by orienting the instrument normal to the magnetic meridian and measuring vertical intensity only, which in the latitude of upper Michigan is equal to 97 pct of the total intensity. The dip needle is seen to be relatively ineffectual for location of anomalies of less than 400 gammas.

Jan 1, 1947

By M. B. Holt

At this time, when electricity in its various applications is attract- ing so much interest, and with such good reason, it has been suggested to me that, as the Aspen Mining and Smelting Company, of Aspen, Pitkin county, Colorado, was the first mining company in America to employ electrical power for hoisting, a record of what has been accomplished by this company would be of interest. Early in the year 1888 the question of power for the development of the ore-horizon lying below the level of the tunnel through which the property is worked, became one of importance. The conditions under which it was proposed to use power were as follows (See Fig. 1): The company's mines lie upon the northwestern slope of a mountain, the ascent of which is at an angle of 28' from the horizon. The ore, consisting of argentiferous galena and other silver-bearing mineral, is found at or near the plane of contact of a superincumbent mass of blue limestone, with an underlying bed of dolomite. This contact plane dips north 30° west, at an angle of 60' with the horizon. A tunnel 1000 feet in length, driven south into the mountain near

Jan 1, 1892

By R. W. Smith, R. J. Charles

Fractions of glass particles in the size range 0.5 to 5.0 were prepared by an elutriator that operates in a centrifugal field. Although mean sizes of commercially graded abrasive powders were ten times greater than those of samples prepared by the elutriator, frequency size plots for elutriator samples compared favorably. Efficiency of separation was low and amounts of material recovered by the elutriator were small, but the method should find use in preparation of small amounts of sized materials for laboratory investigations. R. W. SMITH, Junior Member AIME, Research Assistant, Dept. of Metallurgy, Massachusetts Institute of Technology, is presently with Portland Cement Ass'n., Chicago. R. J. CHARLES, Junior Member AIME, formerly Assistant Professor, Dept. of Metallurgy, Massachusetts Institute of Technology, is Research Associate, Ceramic Studies Section, General Electric Co., Schenectady, N. Y. TP 4261B. Manuscript, Jan. 31, 1956. STUDY of light adsorption, reaction rates, electro-phoresis, particle packing, and corrosion is hindered by lack of a suitable method of preparing small amounts of closely sized materials in the micron and submicron range. Most fractionation methods depend on some form of particle movement through a viscous media in which velocity of a par-

Jan 1, 1957

By Wallace W. Wilson

It scarcely is possible to read a new issue of any of the principal mining trade journals without noting some mention of a major new overseas mining venture with which one or more domestic companies are involved. These projects follow a fairly consistent pattern; most are large open pit mines with relatively low grade orebodies but huge reserves; the total price tag is in nine significant figures and half or more of the total cost is for infrastructure. West' notes that nearly $7 billion is being invested annually for new mining projects and the expansion of existing mining ventures in the free world. He anticipates that by 1975 such investments will reach the $10-11 billion annual figure and that in the period 1972-76 total capital requirements can be expected to aggregate around $45 billion. West estimates that 75% of the total capital will come from internally generated funds. Conceivably, a substantially higher percentage could be attributable to external financing, especially if the trend of recent mineral development in Canada and Australia is any criterion, and including local sales of equity as a part of the package.

Jan 7, 1973

By T. A. Read, M. S. Wechsler, D. S. Lieberman

IN the formation of martensite in steel, it has been observed that the habit plane does not change continuously as the alloy content is varied. Instead, it appears that discrete habits correspond to certain ranges of composition. Greninger and Troiano' found that in low-, medium-, and high-carbon steels, the habits are approximately (1l1), (225), and (259), respectively.* The work of Mehl and Van Winkle2 indicated that the change from the (225) to the (259) habit is fundamentally a consequence of the lower transformation temperature rather than the higher carbon content. Also, Otte and Read3 observed that the habit plane orientation for a chrome-carbon steel scattered within a cone of semivertex angle of 5 deg, which was outside of the experimental error in the determination of the habit plane. These observations suggest the importance of investigating what factors in the crystallography of the formation of martensite account for the several types of habit and the inherent scatter in the precise orientation of the habit plane. A theoretical treatment of the austenite-martensite transformation has been given,4 which considers the total transformation distortion to be composed

Jan 1, 1961

By Robert Glass Cleland

THE CLOSING years of the nineteenth century witnessed a rapid expansion in Phelps Dodge activities in Arizona and other parts of the Southwest and a corresponding decline in its exporting and importing interests in New York. Before the close of another decade, this process had gone so far that the company was committed lock, stock, and barrel to its western undertakings. By 1910 the evolution that began with the tentative investments at Bisbee and Morenci was complete. An enormous increase in the domestic production of iron and copper, which made it increasingly difficult to find markets for imported cargoes of those metals from English mills, accounted in part for this radical shift in Phelps Dodge activities and interests. In the case of tin plate, the change was even more spectacular. In 1890 a seventh of the world's supply of pig tin passed through the hands of Phelps Dodge agents. In 1906, thanks chiefly to the McKinley Tariff of 1890 which imposed a duty of over two cents a pound on tin plate imported into the United States, the company received its last shipment of tin from England, and thus ended a form of

Jan 1, 1952

By Alden B. Greninger

THE time-honored description of the growth of metal crystals to form polycrystalline aggregates is. one in which two important steps are considered: (1) nucleation, and (2) dendritic growth, each dendrite starting from its individual nucleus and resulting (upon slow cooling, assuming no solid phase changes) in a macrograin. This picture of the process of crystallization is incomplete, and it is with the hope of enlarging upon it that the following summary and correlation of experimental results are given. MOSAIC STRUCTURE For an exact definition of the mosaic structure of metal crystals-if, indeed, one can be found that will hold for all metals-one must await the results of much experimental work in this field. The writer's investigations have been. confined almost entirely to copper and a few of its alloys. The following terms are proposed, and will be used in this report: Macromosaic Structure1.-Large-scale mosaic structure; more specifically, mosaic structure of a scale large enough to produce splitting of Laue spots on back-reflection Lane X-ray patterns2. The deviation from exact parallelism of neighboring macromosaics varies from a few

Jan 1, 1935

By R. Gilman Brown

Mines are interesting by reason of what they have done for man, or of what has been done for them by nature. Not all are interesting on both scores. Many profitable mines are commonplace to the geologist; and many presenting unique gcological conditions have been sad failures commercially. The Standard group at Bodie has produced in 25 years, $14,500,000, paying $5,000,000 in dividends.' On the other hand, this output has beeu mined (almost wholly above the 1,000-ft. level) from a system of more than 100 veins, ranging in thickness from 0.5 in. of ('specimen rock" to 30 ft, of clay and quartz; distributed through a zone about 2,000 ft, in width, and representing from three to five distinct periods of formation. This group, therefore, by reason of its industrial record as well as its geological features, may fairly be regarded as doubly interesting. The Bodie district occupies an island of recent (Tertiary) hornblende-andesite, surrounded by a complex of igneous rocks and breccias. It lies at the summit of the eastern foot-hills of the Sierra Nevada mountains, and within the Great Basin, a

Jan 1, 1908

By Zavis M. Zavodni, Carl D. Broadbent

During the past 15 years, rock mass structural properties have become acknowledged as the focal point for rock slope design. Re- search into the methods for measuring and incorporating structure into the design effort has taken many directions and has produced a variety of useful techniques. Among the findings at Kennecott has been the realization that structure-controlled instability can be categorized as regressive or progressive depending on the relative geometries of slope and structure and on the strength characteristics of the structures. It was further identified that a failure condition can initiate as regressive and in time become progressive should external stimuli increase or structure characteristics be altered due to extensive displacements. The transition point has been shown to be a useful indicator of the expectable collapse time. This paper defines three fundamental failure types as dictated by structure and offers discussion on the practical value of such a classification to slope design and failure control. Several prominent examples of failures typifying the categories of structure- controlled instability are discussed. An application of f allure prediction based on the regressive-to-progressive transition point is described.

Jan 1, 1983

By W. M. Courtis

SINCE many accounts of Silver Islet Mine, in Lake Superior, have already been published, it is supposed that the members of the Institute are familiar with the location and character of the mine. To many, however, a more detailed account of the ore and manner of treatment will, perhaps, not be without interest. The extraordinary richness of Silver Islet ores, and the difficulty of obtaining correct assays, induced the company to erect smelting works of its own. Accordingly, ground was broken at Wyandotte, Mich., early in the spring of 1871, and the work was pressed on with indomitable energy by Captain E. B. Ward of Detroit, as president, and Mr. Thomas MacFarlane, the discoverer of Silver Islet, as superintendent of the works, so that by July 1st the works were so far completed that smelting could be commenced. The intention was to work Western ores with those from Lake Superior, since the latter contain but a small amount of lead. Hence the capacity of the works is much larger than is needed for the present yield of the mine. The planned process for treatment was smelt-

Jan 1, 1874

By Kenneth L. Cook

The five serpentine masses exposed within the northern half of Riley County, Fig. 1, constitute a major part of the few exposures of igneous rock in Kansas. Although not many subsurface data are available for this part of Riley County, six deep wells indicate that the basement complex lies between 2500 and 3000 ft below the earth's surface. A northwestward-trending ridge in the present basement surface, which extends across the northern half of Riley County, is indicated on Mettner's contour map. The serpentine masses lie in a region that was active during Pennsylvanian and Permian time along two main tectonic trends, which may, in part at least, have developed contemporaneously. One trend is northeasterly, as evidenced by the Nemaha anticline, the Abilene anticline, the Voshell anticline, and many other smaller northeastward-trending folds. The other trend is northwesterly, as evidenced by the central Kansas uplift, the Salina basin syncline, and smaller northwestward-trending folds. The area of the Abilene anticline was actively deformed during much of this time, and the present surface rocks, for the most part Permian in age, show many normal faults

Jan 5, 1955

By C. F. Cornell, Henderson, A. F. Dunyon, D. A. Dahlstrom

IN processing magnetic taconites several steps of crushing, grinding, classification, and magnetic separation are required to produce a 60+ pct Fe concentrate. Usually the final concentrate is in a slurry form of 55 to 70 pct solids by weight and is further characterized by a particle size of 60+ pct -325 mesh. In taconite plants already completed or under construction the conventional method used to obtain pellets suitable for blast furnaces is to filter the concentrate slurry, ball the filter cake, and then harden the green pellets in a traveling grate or in a vertical shaft furnace. Large tonnages must be handled in minimum floor space, with reduced maintenance and lowest possible operating cost. Filtration must therefore achieve two objectives: 1) high filtration rate-in terms of pounds of dry solids per hour per square foot of filtration area-at a low filtrate solids concentration, and 2) a filter cake moisture that will always permit efficient balling within the normal fluctuations of plant operating conditions. If moisture contents are too high, balling may be impossible or result in a mushy ball without enough green strength for the firing operation.

Jan 3, 1957

By Eugene P. Pfleider, Claus Freyberger

Generally, the different methods of financing new mining projects are not well understood by the engineers and supervisory personnel. Nor are the effects of these alternatives on depletion, taxes and profitability readily apparent to even the sophisticated management personnel without the aid of cash flow studies. Fortunately, with the advent of the computer it is possible now to simulate many different combinations of 1) equity, 2) loan and 3) production payment financing with little effort. A general computer program for cash flow analysis of mining ventures has been developed and applied as a case example to a 1967 feasibility study of the Underground Mining of Minnesota Taconite. The effects on profitability as measured both in rates-of-return and present value are presented for various financing combinations. In addition, percentage depletion rates were altered so as to measure the impact of this statuatory allowance. Based on the cost data as presented in the aforementioned 1967 feasibility study, and assuming 7% loans, the rates-of-return vary from 9. 9% to [00] % on equity variations and from 9. 9% to 11.4% on total invested funds.

Jan 1, 1969

By R. Stanford

In any discussion of steel pouring too often refractories quality assumes a high level of importance. Unfortunately when one considers the many and varied conditions to which pouring refractories are exposed, it is difficult to isolate the true role of refractories quality alone. Some of the more important, yet often overlooked, variable conditions bearing on pouring performance are heat size, tap time and temperature, steel chemistry, ladle additions, ladle height and preheat, mechanical conditions of the pouring mechanism, hot top or non hot topped ingots and, ingot size, which determine total number of shutoffs, direct or tundish pouring, ingot filling rates, metallurgical demands, etc, etc. These considerations apply for either conventional or slide gate pouring of ingots and, to a large extent, even strand casting. In any event probably the most significant factor on pouring performance in any individual shop is what is considered an "OK" pour. We find considerable variance in this qualification, not only between Republic Steel meltshops, but throughout the industry. Therefore, it is a worthless exercise to draw comparisons attributable to refractories quality alone, except for similar conditions in a single shop.

Jan 1, 1972

Earth Sciences: The standard of living of the world's people depends upon human initiative, investigation, and know-how in exploiting the earth's resources. The Earth Sciences-geology, mineralogy, geophysics and geochemistry, meteorology, geography-are basic sciences dealing with those problems concerning the origin, constitution, and utilization of the earth's materials. The development of these fields in one department provides the greatest opportunity for direct contact and stimulus for scientists and teachers working in related fields. In the Earth Sciences, geology and mineralogy are obviously closely related. As rocks are the materials of which the earth is made, so in turn minerals are the constituents of the rocks. Conversely, a study of earth structures and the interplay of physical and chemical forces in the earth is necessary in order to understand the origin and source of minerals. Building on the basic core of knowledge of earth processes, earth structures, and earth history, the geologist will continue to push out the frontiers of stratigraphy, structural geology, pale-biology and petrology with growing insight into principles that control surface and subsurface rock conditions. As the field of geology has advanced, several lines of specialization have developed. The economic geologist

Jan 1, 1950