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By A. L. Holley

The intention of this paper is not to discuss this important subject in all its bearings, but merely to point out why mechanical tests of steel, as ordinarily made, are not, alone, of any special value to engineers—certainly not to general mechanical engineers. The agents of the Barrow Hematite Steel Company, one of the largest and most successful Bessemer establishments in England, have recently distributed a report, made by Sir William Fairbairn,

A rotary chambered blasthole technique has initially indicated a 30% overall improvement in drill and blast department productivity. The method, developed at several open pit copper mines in Arizona, centers around a chambering tool that can be used with existing high-speed rotary drills. The "Chamber Maker," manufactured by the Servco Div. of Smith International, Inc., produces an enlarged section or chamber near the bottom of a large diameter blasthole (Fig. 1). This enlarged cavity permits a greater concentration of explosives at the bottom of the blasthole, resulting in better fragmentation and reduced hard toe problems, and also lowers the number of blastholes required to break a bench area, says Servco's Gerald W. Laswell. Cost savings can therefore be achieved in reduced secondary blasting requirements, increased shovel efficiency, and subsequently, less shovel maintenance. All these factors would serve to lower the overall mine cost per ton figure

Jan 3, 1975

By T. M. Morris

The forces acting between a small rod, one end of which was made water repellent, adhering to a much larger air bubble in water were measured. An equation is deduced which correlates these forces and the influence of each force is discussed. The importance of the size of bubbles in a flotation cell is emphasized.

Jan 1, 1950

W. VAN DER GRACHT, Tulsa, Okla. (written discussion.*).-I fully agree with Mr. Daly's observation that there is such a coincidence between petroleum deposits and geosynclines as to suggest them to be "closely allied phenomena." However, I accept no "identity of cause." To me the explanation is a simple one. Geosynclinal deposition is the first phase in the formation of a mountain, chain, and petroliferous deposits are indeed closely allied to zones of, mountain folding. In fact, petroleum is a typical occurrence in those beds, which represent the flysch facies, to use the Swiss expression. The uplifting of a great mountain chain is a very slow process; it gradually sets ill as a slow geo-anticlinal upheaval within a zone off former geo-

Jan 1, 1918

The primary purpose of the Institute is to advance the technologic and engineering arts embraced by it through interchange of knowledge This can best be done by the presentation and discussion of technical papers by its members Short practical papers are especially welcome An author should always satisfy himself that his material is of a quality that will be a credit to him and to the Institute The preparation of a good paper frequently leads to a reorientation of the author's thoughts, and publication contributes much to the professional standing of the author Members are urged to submit papers presenting the results of their work Attention to the following suggestions will greatly further the prompt and efficient handling of manuscripts

Jan 1, 1952

By Neil Styler

This paper presents an analysis of measurements of inter-burden deformations above six longwall faces. An attempt is made to demonstrate some correlation between the movements at the various sites, and to examine their importance with respect to predicting caving height, disruption of overlying seams, and disruption of aquifers. This analysis demonstrates some significant differences between predicted surface subsidence, and inter-burden deformation. In addition it is shown that the caving height above a longwall face is equal to 8 to 12 times the extraction height, with a zone of fractured rock extending to approximately 50 times the extraction height above the seam.

Jan 1, 1984

By William E. Ford, Edward Salisbury Dana

1. Normal Class (31) Axinite Type 2. Asymmetric Class (32) Calcium Thiosulphate Type Mathematical Relations of the Triclinic System 216. Crystallographic Axes. - The triclinic system includes all the forms which are referred to three unequal axes. with all their intersections oblique. When orientated in the customary manner one axis has a vertical posi-

Jan 1, 1922

Jan 1, 1913

By Daniel T. Hegyan, Thomas B. Zugates

Continuous vacuum disk filters are increasingly being used to filter refuse from the fine-coal washing circuits as it becomes important to close the water circuits and eliminate sludge holding ponds. This paper discusses our past experience filtering refuse, effects of solids concentration in the filter feed, use of polymer flocculation aids, effect of flocculation devices, and effects of particle size and ash content on the filtration rate. Detailed tests were performed on existing installations utilizing coal refuse filters to determine optimum flocculant dosage, solids concentration, and disk rotation speed to form a dischargeable cake. Information was also obtained showing effect of flocculant addition on the moisture of the filter cake.

Jan 1, 1977

By B. Ball, C. H. Cox, S. N. Yap

Electrokinetic measurements on cassiterite were made in the presence of sodium di-hydrogen phosphate, mono-hydrogen arsenate, bisulfite, and sulfate. Flotation studies were also conducted using sodium dodecyl sulfonate in the presence of these salts. It was found that the anions specifically adsorb on cassiterite in the order H2AsO-4 H2PO4 HSO3 SO4 and consequently cause flotation depression. The adsorption mechanisms of the various inorganic anions are discussed in detail.

Jan 1, 1980

By S. C. Sun, D. R. Mitchell

T LTRASONICS can be used to deslime and up-grade ores, such as tungsten and tin, which slime excessively with high losses of value in the tailing and are difficult to deslime with conventional methods. Experimenta] work has been performed with a test-tube size ultrasonic classifier. Larger equip-

Jan 1, 1957

By Theodore H. Orem

In 1928 Elam,1 discussing the subject of twinning in metals, disclosed that she had observed this phenomenon in aluminum, a metal little susceptible to twinning. The twinning described was one in which the boundary between the twinned portions was not a geometric plane but appeared, in one section, more like a normal grain boundary. Under these circumstances twinning might remain unrecognized by an observer of microscopic sections. She therefore suggested that twinning in aluminum might be much more prevalent than expected. Whereas the parallel composition lines shown in sections of polysynthetic twins were characteristic of the phenomenon of twinning, Elam pointed out that from the absence of

Jan 1, 1963

By J. R. Eickmeier

By G. A. Perry, C. D. Iles

The philosophy used in designing and writing Duval's Sierrita mine design programs is discussed. The Sierrita Incremental Design system (SID) is reviewed with emphasis on Pushback Extraction Design (PED). PED is a method by which predesigned pushbacks are sequenced into an optimized period-by- period design. The design that PED Produces is the design used in the field without further modifications. The advantage of SID is that it provides a practical, mineable open pit design. PED is not a theoretical design system. It is in operational use.

Jan 1, 1984

By L. T. Larson, P. M. Basinski

In the northern Reese River Valley uranium is corroded with Middle Pliocene zeolites. These zeolites were diagenetically derived from rhyolitic volcanic glass deposited in a saline- alkaline lake. X-ray diffraction, scanning electron microscopy, and chemical studies reveal clinoptilolite, analcime, and enonite to be pesent and that these minerals can concentrate at least 0.7% uranium from solution. Most anomalous drill cuttings contain zeolite and zeolites are believed to host the uranium. Research suggests the uranium mineralization is conceptually analogous to the Tono mine, Japan.

Jan 1, 1981

By R. Schuhmann

Distribution of material in the fine sizes of a comminution product generally is well represented by the empirical equation [ ] in which y = cumulative percent finer, x = particle size, = distribution modulus, and k = size modulus. Charles found that the energy consumption in comminution is usefully expressed by another empirical relation, [ ] in which E = energy input per unit volume of material, A = a constant, k = size modulus based on Eq. 1, and n = a constant; ( 1-n) is the slope of a plot of log E vs log k. Holmes has presented energy equations similar to Eq. 2.

Jan 2, 1960

By Persifor Frazer

AMONG the geological problems with which the present Pennsylvania Geological Survey has had to deal is the relative age of a series of strata passing around and through the city of Philadelphia, Bucks, Chester, and Delaware counties. Rogers includes all these rocks in his hypozoic series, and every student, so far as the writer knows, with one exception, has assigned to them a position beneath the Potsdam sandstone, or " Primal " of that eminent and gifted geologist. So far as regards the small portions of this belt, to which it is the intention of the present paper to draw attention, even the one geolo - * Read at the Lake Superior Meeting, August, 1880.

Jan 1, 1881

By H. I. Aaronson, S. M. Kaufman, G. M. Pound

WHETHER the carbides associated with bainite precipitate from the ferritic component of bainite, as originally suggested by Davenport and Bain, or from the adjacent austenite at aus-tenite:ferrite boundaries, as proposed by Hultgren, 2 remains in dispute.3-5 A recent metallographic investigation in this laboratory has shown that the bainitic carbides formed in a plain carbon hypo-eutectoid steel nucleate entirely within ferrite at higher reaction temperatures3 and in both ferrite and austenite at lower temperatures." The present investigation was undertaken to ascertain the effects of alloying elements on the nucleation sites selected by bainitic carbides. The compositions of the steels studied were as shown in Table I. Specimens of these steels were

Jan 1, 1958

By Stephen E. Erickson

MORE and more hydrocyclones are being installed in beneficiation plants. This recent rapid increase is of special interest in the history of beneficiation, since development of the hydro- cyclone appears to have swung in a circle. To avoid any chance of confusion, it would be well first to review the accepted definitions. The size of a cyclone is expressed as the diameter of the cylindrical section. Size of the inlet orifice- which may be circular, square, or rectangular- is expressed as a diameter, or as width and length, or as an area (in square inches). The angle of a cyclone is expressed as the total included angle. The overflow or finest classification fraction leaves the cyclone through the vortex finder. The underflow or coarsest classification fraction leaves through the apex opening.

Jan 8, 1957