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By W. J. Keep

We have found that our graphic representations were, in some cases, not perfectly understood. In the tables by which we illustrate all our tests, the records appearing in the vertical columns between the rulings are the results of the tests of iron having the percentages and characteristics noted at the top of the column. The record is made by a short horizontal line in such vertical columns. It is located in horizontal spaces, which divide the table into units of measure, to indicate the value of the record. For example, in the upper part of Table VII. is recorded the transverse strength of the series of tests with white iron and aluminum, which were reported in our former paper. The numbers at the extreme top are the test-numbers. The fractional numbers below are the percentages

Jan 1, 1890

By W. C. Kerr

A BRIEF sketch only is here intended, with a few illustrations, in order to give a general notion of the character and structure of these veins. I have stated elsewhere, several years ago, that these veins were wrought on a large scale and for many ages by some ancient peoples, most probably the so-called Mound Builders; although they built no mounds here, and have left no signs of any permanent habitation. They opened and worked a great many veins down to or near water-level ; that is, as far as the action of atmospheric chemistry had softened the rock so that it was workable without metal tools, of the use of which no signs are apparent. Many of the largest and most profitable of the mines of the present day are simply the ancient Mound Builders' mines reopened and pushed into the hard undecomposed granite by powder and steel. Blocks of mica have often been found half imbedded in the face of the vein, with the tool-marks about it, showing the exact limit of the efficiency of those prehistoric mechanical appliances. As to the geological relations of these veins, they are found in the gneisses

Jan 1, 1880

By Ray W. Ballmer, K. H. Matheson

Since start-up in 1906, Bingham had been a rail pit, beginning with steam locomotives and converting to electric locomotives in 1923. Ore production was maintained by effective utilization of avail- able rail equipment. From time to time, as it became necessary to deepen the pit and as stripping ratios increased, studies of alternative material haulage systems such as diesel locomotives, conveyor belts and trucks were made. Conversion from rail haulage with electric locomotives could not, however, be justified. Because of a gradual decline in ore grade, a program was approved in 1963 to raise ore production to 108,000 tpd. The decision posed a serious problem: due to built-in inflexibility and other limitations, a parallel expansion of the rail haulage system was impractical. (Track and trolley wire relocation causes greater shovel downtime than required for normal maintenance; instability of the dumps and the resulting additional track maintenance increases greatly as the daily volume of waste material increases.) Studies indicated that economically the most favorable course of action would be the replacement of rail haulage on the upper levels of the mine by truck haulage.

Jan 11, 1965

By Alan U. Seybolt

IN examination of some cold-rolled copper and cupronickel that contained a little columbium, it was discovered that these alloys were unusually resistant to annealing. This effect was sufficiently pronounced to warrant some investigation [ ] of the annealing characteristics of such compositions. EXPERIMENTAL PROCEDURE The alloys were made from cathode copper, electrolytic nickel, and a special copper-columbium hardener alloy furnished by the Electro Metallurgical Corporation. This hardener alloy contained 10 per cent columbium, with tantalum, aluminum and iron as major impurities. The melting was carried out in a clay-graphite crucible in a high-frequency induction furnace, under a charcoal or [ ] electrode carbon cover. No deoxidizing additions were made. The 7-lb. copper heats were poured into a steel mold, hot-rolled to ¼ -in. thickness, and annealed for ½ hr. at 760°C.; the cupronickels were annealed I hr. at 815°C. The material was then cold-rolled to a go per cent reduction in thickness and annealing tests were carried out on this 1/8-in. hard-rolled strip. A little silver was added to copper-columbium alloys 402 and 403 to find out

Jan 1, 1941

L. C. GRATON, Cambridge, Mass.-I should like to ask the authors if they attempted to draw any analogies with the manganese deposits at Franklin Furnace, N. J., and whether there are. any traces of zinc in these Brazilian-deposits. J. T. SINGEWALD, JR.-We did not think of them at all as analogous to the Franklin Furnace deposits and there is no appreciable percentage of zinc present. If these ores do contain zinc it could be there 'only as a fraction of a per cent. F. LYNWOOD GARRISON, Philadelphia, Pa. (communication to the Secretary *).-There is no disputing the fact that the manganese ore ,supply situation in this country demands serious consideration and is a matter of fundamental public concern. We are consuming this material at a steadily accelerating rate and there is no hope for a proportionate increase in the domestic supply. In the year 1916, this country imported 560,000 tons and produced only 27,000 tons from our own territory In 1915, the local production was 9,709 tons, which on its face shows the American output to have tripled during the past year. Those of us who are familiar with the

Jan 4, 1917

By L. O. Howard

MUCH work has been done recently on the lead-antimony system1 in connection with lead-rich alloys of commercial importance containing less than 20 per cent. antimony. Dean, Zickrick and Nix have called attention to the perpetuation in the literature of several erroneous data, such as a eutectic temperature of 228° C. at 12.5 per cent. antimony, instead of 247° at 13 per cent. The series is given as a classic example of a straight eutectiferous series in such late books as those of Heyn and Grossmann,2 Jeffries and Archer,3 Guillet and Portevin4 Pulsifer,5 Rosenhain,6 and Liddell,7 as well as the somewhat earlier works of Hofman (1918), Wang (1909) and Williams (1920). The work of Dean has definitely showed a solid solution of antimony in lead at about 2.5 per cent. antimony. While lecturing to a class in general metallurgy at the University of Idaho, the writer had the students prepare a series of lead-antimony alloys for the purpose of illustrating methods of thermal analysis. Proper proportions of powdered antimony (sold as C.P.) and test lead were mixed and melted in graphite crucibles under a reducing cover. Cooling

Jan 1, 1928

By R. McEwen, G. W. Hansen, G. F. Lee

The effect of using an anionic collector, Reagent 308, a sodium petroleum sulfonate, with a cationic collector, Armac T, a tallow, fatty acid amine acetate, was studied in a series of monomineralic flotation trials with the alkali feldspars and heavy minerals, ilmenite, rutile, garnet, and monazite. This combination of cationic and anionic collectors is employed to float feldspar and heavy minerals from quartz in the beneficiation of sand in Normanville, South Australia, to produce a suitable quartz sand for glassmaking. In the alkali feldspar trials, Armac T additions were held constant, while the 308 additions were varied. In the heavy mineral trials, the 308 was held constant while the Armac T was varied. Peak enhancement of the feldspar recovery was noted when the 308 additions were between 25% and 150% that of the Armac T additions. At higher 308 addition, depression of feldspar flotation occurred. This appears to be due to a neutralizing effect in the combined collector system and to the formation of a nondissociating complex of both collectors. This variability in flotation response when Armac T is used with 308 suggests that the two collectors do not act independently of each other.

Jan 1, 1977

Would you briefly describe how you chose the minerals industry and reflect upon some of your earliest experiences? I wish that I could say that I had a well-formulated career plan early in life and that mining engineering was always foremost in it, but I cannot, In fact, I was quite indecisive before I finally chose my life's vocation. But in another respect, I am glad my career unfolded in the manner it did because it gave me a better insight into advising others on career opportunities. Probably the greatest problem confronting our youth, and the one I find preys upon their minds the most, is their inability to select a career path early in life. This indecision frequently has a deep psychological effect upon them and they become down on themselves. Therefore, it fortifies them somewhat to learn that others who have become successful in their careers had difficulties choosing a career path early in life. However, while assuring young people that an early choice is not absolutely essential for success, I caution them to work toward as early a decision as possible.

Jan 3, 1979

By R. W. Raymond

Most of US, in this hurrying age, take little pains to preserve such records of our doings as will make the work of' our biographers easy. Now and then there is an exception, and Dr. Trippel was one. Methodical in all his habits, he kept diaries and journals comprising his own personal experiences, the details and results of his numerous scientific investigations, and his impressions concerning men and events; and also copies of all his technical essays, published by various societies or periodicals. It is a striking instance of " the irony of fate," that these carefully-preserved materials, which would now have a real historical, as well as biographical value, were totally destroyed by an accidental fire a few years ago. In addition to my own recollections of an acquaintance covering more than thirty years, I am indebted, for the fads upon which this sketch is based, chiefly to Mr. Engene J. Trippel, a son of the deceased, and now Register of the United States Land Office at Tucson, Arizona. Mr. Trippel, however, frankly confesses that his own knowledge of his father's work is, in the absence of written records, imperfect.

Jan 1, 1898

By Joseph N. Morrison

A comprehensive solution is offered to the problem of dust emissions at belt conveyor transfer points. Details of enclosure design are discussed and a straightforward procedure for calculating required dust control exhaust volume is presented. Many design variables are taken into account which heretofore have been commonly ignored or inadequately considered. These include belt widths, belt speeds. enclosure openings, material flow rate, material bulk densities, material lump sizes, height of material fall, material temperature, and ambient air temperature. All of these questions are handled by means of a "fill-in-the-blanks" type of calculation form, permitting quick, reliable solutions by relative "non-experts."

Jan 1, 1972

The word "engineering" should not be considered as all-inclusive. Perhaps it should be redefined at this time. Various fields of learning that are indispensable to the locating, beneficiating, processing and using of minerals cannot be classified properly as engineering. For example, in locating deposits, the sciences of paleontology, stratigraphy, mineralogy, petrology, petrography, geo- chemistry, economic geography, and mineral economics might be involved. Beneficiating, processing, and using go beyond the normal scope of engineering to include fuel technology, physical and organic chemistry, physical and atomic metallurgy, and ceramics. Fifty-eight institutions of higher learning in the United States offer curricula in one or more subject-matter fields of the mineral arts and sciences. Thirty-four curricula are offered in mining; 42 in metallurgy; 17 in petroleum and natural gas; 13 in ceramics; 1 in fuel technology; 23 in geological engineering; 8 in geology; 4 in geophysics; 2 in mineral preparation; and l in mineral economics.1 Under given conditions, some of these curricula probably could be eliminated without the slightest retardation in the rate of advancement of knowledge concerning the science of mineral discovery, extraction and utilization, but it is no credit to mineral industries colleges that five departments of mining per-

Jan 1, 1950

By G. R. St. Pierre, R. D. Blackburn

Oxygen contents of' liquid-iron alloys saturated with oxides are analyzed. Minimum points observed in particular Fe-X-O systems can be predicled by a simple extension of first-order interaction methods. If minimum oxygen content occurs at N; where r is the ratio of metal to oxygen in the oxide phase. RECENTLY, wisher' reported on solubility measurements of A1203 in liquid iron at 1580°C which support the earlier work of d'Entremont, Guernsey, and chipman2 and Gokcen and Chipman. Swisher's diagram is reproduced in Fig. l. Minimum points in oxide solubilities have also been found in the Fe-Cr-0 system,4 Fig. 2, and the Fe-Ti-0 system,' Fig. 3. Minima positions can be used to confirm approximately the measured first-order interactions, &, cgr, and E&~, in liquid iron and to deduce compositions of components of constant activity in the oxide phases. Consider the solution of Alz03 in liquid iron: for which an equilibrium constant can be written as: differentiating Eq. [2] with respect to Na~, the atom fraction of &l in the metallic solution, and noting that If the activities of Al and 9 are expanded by a first-order interaction model, then:

Jan 1, 1969

By A. V. Henry, W. Harry Vaughan

THE kaolins of the southeastern United States were known to civilization as early as the latter part of the eighteenth century-and yet the [ ] commercial history of Georgia kaolins may be said to begin in the year 1900. The U. S. Bureau of Mines reported for that year a production of 6885 tons of "miscellaneous" clays in Georgia. A comparison of these figures with those of 1934, when the production rose to 284,556 tons (65 per cent of the domestic production), indicates the growing economic and technologic importance of this raw material. Fig. 1 clearly shows that a part of the increase is due to a normal growth in the use of kaolinitic clays and a part is due to replacement of clays formerly imported. Occurrence Georgia kaolin occurs in an irregular belt extending diagonally across the middle of the state, a distance of approximately 225 miles. This belt

Jan 1, 1937

By J. H. Bramwell

THE following experience in rebuilding a furnace crucible while in blast may not be wholly uninteresting to some, notwithstanding its purely practical character. Few are aware of the frequent calls made on a furnace manager's skill and ingenuity, to meet the irregularities which present themselves with kaleidoscopic variations in the operations of furnaces. Unfortunately the methods pursued in overcoming these practical difficulties are too seldom recorded, and much valuable information is lost that could not fail to be of value to many, and to none more so than the educated technical manager, with a limited practical experience, who, without a literature or record of any kind to refer to, finds himself, in times of emergency, dependent and looking for assistance from those whom it is his province to instruct and direct. With positive data, however, that like difficulties have been successfully overcome, he can confidently resort to similar expedients, with such modifications as the circumstances may demand in his particular case, and pull through seeming impossibilities in the face of ignorant prejudice. The Quinnimont Furnace (60 x 15 feet) had been in operation but two months, when it became necessary to draw the tuyeres out a distance of 18 inches, in order to give them a resting-place; the brickwork under them being completely cut away, so that after each

Jan 1, 1877

MELTING in a crucible is the customary method for small things. It is done in two ways: with the blast of bellows and with an air furnace. The one with bellows, which I wish to show you now, is the common method most in use. It melts quickly and is very well known to goldsmiths and to all melters. I could continue without telling you of it, but I shall tell you its method in order to caution you about what you might perhaps not notice. In order to do this, first make a little forge with a pair of bellows that can be worked with one hand or in some other way. A crucible of the size needed is then taken and filled with the material that you wish to melt. Then, on the forge in front of the place where the wind issues from the bellows, kindle as much charcoal as you think will well cover your crucible and put your crucible full of material in the midst of this burning charcoal above the place where the blast strikes the fire, two or three dita distant from the place where the blast issues-or as much more or less as the size of the crucible or the force of the bellows requires. It is allowed

Jan 1, 1942

By F. B. Richards

For the last five years the furnace-men drawing their oresupply from the Lake Superior districts have had to solve the problem of using the very fine Mesabi ores as part of their oremixture. It is not my purpope to dwell on the early experiences and the progressive development in the use of these ores up to this time, but to lay before the members of the Institute one prominent feature concerning them, namely, the frequent and sometimes very disastrous slips (?) or explosions (?) occurring at furnaces where these ores are used. The Transactions of the Institute contain very little on this subject. Mr. F. E. Bachman, in his discussion of Mr. 0. 0. Laudig's paper (Trans., xxvi., 1061), advances a theory as to the cause of these occurrences; but this is the only reference to the subject in the Transactions up to this time, so far as I can recall. Probably all the furnace-men running the harddriven coke-furnaces in the central West have had more or less experience with this trouble; and I believe the majority of

Jan 1, 1899

By D. D. Porter, C. Fairhurst

Crack propagation in the region of a statically pressurized borehole is investigated to determine a role of the sustained borehole pressure following detonation in a blast. The case of a single-hole bench blast is reduced to a plate model, which is considered both theoretically and experimentally. Based on the principle of least work, it is hypothesized that the path of any crack in the plate will coincide with one of a family of maximum principal stress trajectories. These trajectories were computed, and critical experiments in glass, designed to test the effects of controlled crack origin and of changed trajectories from different loading configurations, confirm this hypothesis. It is concluded that under ideal conditions the crack path can be predicted and that cracks can be produced in the absence of either high-amplitude stresses or stress waves. Energy considerations for crack extension are discussed, and, based on the strain energy distribution, a relationship between hole burdens and spacings is revealed, a critical burden is demonstrated, and a maximum crater width is shown to exist.

Jan 1, 1971

By J. H. Brophy, A. I. Prill

The authors have previously investigated the solid-state activated sintering of tungsten powder with various Ni-Cu additions.' Log shrinkage vs log time plots showed changes in slope from 4 to x at intermediate times during the sintering process. This was attributed to a change in the rate-controlling mass-transport process from solution of tungsten into the tungsten-alloy interface to diffusion of tungsten in this interface. It was postulated that the melting of the activating layer should not affect this transport process. However, the superposition of rearrangement due to the presence of a liquid phase complicates the data analysis. It is the purpose of this note to apply the analysis of Prill, Hayden, and rohy' to account for "rearrangement shrinkage'? in liquid-phase sintering of the W-Ni-Cu system. This results in "solution-precipitation stage" shrinkage plots which were comparable to those obtained in solid-phase activated sintering of the same system. If one assumes total shrinkage to be the sum of rearrangement and solution precipitation, the effects can be isolated easily.2 This results in the general equation:

Jan 1, 1967

By Ta M. Li

US mine-related fatalities were reduced by 10.3% at metal and nonmetal operations in 1974, according to a report by the Secretary of the Interior to Congress concerning the administration of Public Law 89-577. While there was no significant change in the overall injury experience, the 157 fatalities were the lowest recorded in the mining industry since federal mine inspections began under the Act in 1970. The report attributes this reduction to the "improvement in the quality and increased size of the inspection force as well as the continuing emphasis on mine safety conditions and practices." The year 1974 represents the first full calendar year in which the Mining Enforcement and Safety Administration (MESA) had responsibility for administration of the Federal Metal and Nonmetallic Mine Safety Act, and the Federal Coal Mine Health and Safety Act of 1969. Prior to MESA's establishment in 1973, these functions were delegated to the US Bureau of Mines. Research activities in health and safety were continued by the Bureau in 1974.

Jan 12, 1975

By Eugene Guccione

FOREWORD-In an interview published in the May 1975 issue of MINING ENGINEERING, one of the world's most respected scientists, nuclear physicist Hans Bethe discussed the reliability of nuclear power plants and their unmatched safety record. The Nobel laureate also refuted the anti-nuclear lobby's claims that nuclear plants emit harmful radioactive effluents. When asked whether the US has sufficient uranium resources, Dr. Bethe replied that "it depends on the time of introduction of the commercial and advanced breeder reactors which, in effect, can generate more nuclear fuel than they consume." The United States has enough U3O8 to last until the breeders can take over in 1995, said Dr. Bethe. But lie warned that extensive environmental damage would be caused if "environmentalists" succeed in delaying the development of the breeder. Any such delays, he noted, would vastly increase the demand for U3O8 in conventional reactors; this, in turn, would impose an immense burden on the US uranium mining industry, which would then have no alternative but to mine the low-grade Chattanooga deposits.

Jan 4, 1977