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By C. G. Dunn, P. K. Koh

TWO recent review papers have considered the origin of primary and secondary recrystalliza-tion textures from the point of view of oriented nucleation and oriented growth theories."' Both theories require nuclei for primary recrystallization but provide no unequivocal answer to the question of what nuclei are. The answer to the same question regarding secondary recrystallization, however, often is that nuclei are certain primary recrystallization grains or primaries. The two theories differ, however, in specifying what the certain primaries are. In support of the oriented growth theory Beck and Hua originally stated "It may be assumed that in a re-crystallized material, even with a strong texture, there always are present some grains of practically any orientation. These may serve as nuclei for the coarse grains, provided that conditions are favorable for their growth." In commenting on this statement one would say that there are two restricting conditions: namely, that 1) the certain primaries (nuclei) are large enough to grow, and 2) their boundaries have high mobility. More recently Beck2 has con-

Jan 1, 1958

By H. F. Yancey, O. L. Furse

Although usually coal is screened with punched plate screens having round-hole perforations, there has been an increasing use of wire-cloth screens with square apertures, especially at pneumatic coal-cleaning plants and at other plants that use vibrating screens. It is therefore desirable to establish a relationship between round-hole and square-hole screens for use not only in experimental investigations of coal-preparation problems, but also for use in commercial operations. This need is apparent whenever it is necessary to substitute wire cloth for punched plate and still retain the familiar trade-size product. Although similar work probably has been done by industrial organizations concerned with the screen sizing of coal, the only recorded study of the subject other than the one described herein of which the authors are aware is that of Roesler,1 who screen-sized two samples of limestone and two of zinc concentrates crushed to pass 1/2 in. with a set of square and round-hole screens and found the ratio to be 1:1.23. Procedure In the course of a study of various methods for determining the friability of coal,2 it was necessary to screen-size the products of a series of friability tests of three different coals with both round-hole and square-hole screens. The coals used were from the Roslyn No. 3 and the Bayne mines in Washington and the Rolapp mine in Utah. Twenty 25-lb. samples of each of these three coals at 3 to 2 1/2 in. round-hole size were dropped from a height of 10 ft. to a concrete floor, and then screened with

Jan 1, 1934

By I. A. Lange, A. M. Richardson

Although methods for determining shaft lining thickness are well documented, little attention has been given to the design of station breakouts and other related shaft ground support structures. This paper discusses design of selected shaft structures for the Cathedral Bluffs project, a planned 54-kt/d (60,000-stpd) oil shale mine in western Colorado. Design philosophy and construction sequences used in the three completed 520-m (1700 ft) deep, 4.6-m (15 ft) to 10.4-m (34-ft) diameter shafts are described.

Jan 1, 1984

By D. G. Westlake, U. F. Kocks

WHILE single crystals of most materials with cph lattice structure show essentially unlimited ductility, polycrystalline specimens of the same materials exhibit the entire range of ductilities. A difference between the ductility of single crystals and polycrystals may be associated with the special stress concentrations to be expected, for example, at the intersections of slip bands or twin lamellae with grain boundaries. Whether such stress concentrations prove catastrophic depends on the cleavage strength of the material, the size of the stress concentrations, and the speed with which they are formed. Thus, the ductility may vary in degree from material to material. Another possible reason for differences in ductility between single crystals and polycrystals is that a sufficient number of independent deformation modes must be available to insure compatibility between the macroscopic strains in neighboring grains.''2 This criterion is often taken to be a necessary condition for any polycrystal ductility whatsoever, not as one that determines different degrees of ductility; thus, a material with an insufficient number of independent deformation modes would have to be brittle as a polycrystal. The "sufficient number" is five if every grain is to accommodate arbitrary shape changes ("von Mises criterion "). We should like to argue that fewer than five independent modes may be sufficient to satisfy compatibility conditions; and that the internal stresses set up when the plastic strains are not compatible reach the theoretical fracture stress only after a significant amount of macroscopic strain has taken place which may vary in magnitude from case to case, allowing an influence on the degree of ductility. Experimental evidence for these statements is taken from the following review of the number of independent deformation modes observed in the various cph

Jan 1, 1968

Jan 1, 1961

Jan 1, 1959

By R. F. Davis

The evaluation and selection of coals for producing metallurgical coke is indeed a complex process simply because coal is a complex and variable substance which is sensitive to how it is treated from the time it is mined until it is transformed into coke. A review of some of the more common evaluation tests made on coal and how the test results are applied in commercial practice should be of interest. Parameters used to select coking coal blends for wet and preheated charges should also be of interest.

Jan 1, 1982

By E. Tulcanaza

The practical significance of the in situ grade variability is usually neglected. Although recognized, often times it is either ignored or just considered as a vague guideline in many of the decisions dealing with exploration, reserve estimation, and mine planning. This paper stresses the significance of grade variability for exploration and mining, and illustrates its liaison to the structural features of the ore deposits, as well as to the mining parameters used for mine extraction. Some geostatistical results obtained from a silver mine, tungsten mine, and copper mine in South America are discussed.

Jan 1, 1985

By K. G. Colman

This text is intended to provide the operator and turn-key contractor with the basic data for sizing vibrating screens to be used in ore crushing plants. The basic capacities, modifying factors, etc. used in the area requirement calculations were developed empirically and modified to their present values based upon years of practical applications. It must be pointed out that screening is much more of an art than an exact science, however, the information presented here should provide for reasonably accurate screen sizing when applied to metallic ores .

Jan 1, 1978

By AIME AIME

CONVENTION plans for the A.I.M.E. Regional Meeting to be held on the Minnesota Iron Range Aug. 12 to 1.5 are being completed to give the visiting member?s from all parts of the country a wide variety of technical and recreational features. High spots of the social events are the official dinner, dance, luncheon and golf: and of course, special provision is being, made for the entertainment of visiting ladies. The technical sessions will fit in with scheduled trips to view all phases of mining, beneficiation and transportation of iron ore. Men from the West and Southwest will find much of interest in the detail of the mining operations. A trip to the steel plant of the

Jan 1, 1941

By C. J. Bise, E. K. Albert

Mathematical modeling and computer simulation are the two primary techniques used for production analysis of underground coal mine layouts. Oftentimes, however, the selection between these two techniques is not based on an awareness of the level of effort needed for input formulation versus the suitability of the desired output. This paper will review mathematical modeling and two of the more prominent simulators (Virginia Tech's FACESIM and Penn State's UGMHS) used in underground coal mine production analysis. A hypothetical section will be analyzed by these programs and, based on the results of the aforementioned study, their advantages and disadvantages will be discussed.

Jan 1, 1985

By M. I. Kabir, R. S. Schechter, L. W. Lake

This paper presents the development and application of a novel scaling technique that, when used with a streamline model, causes a "bundle" of one-dimensional (1-D) problems to reduce to a single 1-D calculation. The 1-D bundle is the streamline representation of a two-dimensional (2-D) problem. The 1-D calculation accounts for chemical-rock interactions and the streamline model for areal sweep. The scaling technique significantly reduces computation time, is readily modified to desktop calculations, and can be applied to both absorbing and reacting species. The work was sponsored by the US Bureau of Mines.

Jan 1, 1986

By F. M. Perkins, R. H. Jamison

Publications concerning scaling laws for laboratory flow models of oil reservoirs indicate that the relative permeability and capillary pressure relations must be the same functions of saturation in the model and its prototype. In this paper, the relative permeabilities and saturations are redefined in a way which permits one to have diflerent relative permeability and capillary pressure relations in the model and prototype. The development of the new scaling criteria is demonstrated by deriving scaling laws for one simple flow problem. INTRODUCTION The successful application of information gathered through bench-scale model studies to the prediction of multi-phase fluid flow behavior in petroleum reservoirs requires careful consideration of the scaling criteria. The requirements which must be met for a small-scale model to duplicate the behavior of a much larger reservoir prototype have been discussed by Leverett, et al,' Rapoport,2 and Geertsma, et al.3 According to these authors, the relative permeabilities to water, oil and gas and the dimensionless capillary pressures must be the must have the same values in the model and prototype. Furthermore, they point out that the viscosity ratios must have the same values in the model and prototype. In addition to these requirements, other scaling criteria are given which, when considered, usually dictate a much higher permeability in the model than exists in the reservoir. Since the more permeable model sands may have connate-water and residual oil saturations quite different from those in the prototype, the scaling requirements pertaining to the dependence of relative permeabilities and dimension l ess capillary pressures on saturation usually are not met. Also, if the model fluids are selected to give equal viscosity ratios in the model and prototype, one may find greatly different mobility ratios* in the two cases and, therefore, may expect grossly different flow patterns. For this reason, Craig, et al,' correlated the results of their model studies with mo- bility ratio rather than with viscosity ratio. As yet, however, no satisfactory method has been advanced which permits use of anything other than the scaling requirements outlined in the previously mentioned papers. The purpose of this paper is to present a method of developing a set of scaling criteria which permits different relationships between saturation and relative permeability or capillary pressure in the model and prototype. Rather than attempt to report scaling criteria for a variety of practical situations, this paper demonstrates by use of one simple example how the modified scaling criteria are derived.

By Gen-Hua Shi, Richard E. Goodman

In hard, discontinuous rocks, failure modes and stability are controlled to a great extent by the intersection of discontinuities with the excavated surface. We have solved the general problem of finding the shape and size of all blocks formed through the inter- section of any number of joints and excavation surfaces and will demonstrate a simple graphical method for determining which of these is the "keyblock." An example will explain this methodology applied to a simple open pit. The effects of slope curvature in plan or section, will be demonstrated. Finally, we will show how to determine the optimum orientations for the cut slopes. The methodology is based upon a powerful topologic theorem concerning the finiteness of spatial intersections. This paper is a companion to another dealing with underground openings in the Proceedings of the 22nd Symposium on Rock Mechanics (MIT) , July 1981. This paper discusses the rock blocks created by the intersection of discontinuities and excavation surfaces in a rock mass. It establishes principles and procedures by means of which those blocks that are finite and critically located can be identified and described. The main assumptions are the following: 1. The rock itself is assumed to be strong so that the only concern for stability is the movement of rock blocks them- selves.

Jan 1, 1983

By Richard Moldenke

AmonG the things that will always remain to the credit of the foundry-industry is the circumstance that nearly all the research-work of practical value in daily routine was done by active foundrymen, and the results were freely given by them to the world. Moreover, while consumers felt that to them was due a more systematic and exact method of work, the foundry-men again were the first to act in the establishment of specifications under which their product should be sold. To come to more recent times, the American Foundrymen's Association has not only made an elaborate series of tests on cast-iron, and adopted tentative specifications based upon them, but, in addition, it has urged the International Association for Testing Materials, through its American representatives, to make the testing and specification of cast-iron a distinct issue. The half-hearted support first granted was greatly augmented by the rapidly-growing recognition accorded to the enormous iron-casting industry; and when the president of the American Society for Testing Materials was instructed to ask for a special commission for this purpose, Europe was ready to cooperate. During the Buda-Pesth congress, at, which America was represented by Prof. Howe, Mr. Wood and myself, it was decided to add five members to the general committee on steel and iron, whose special duty should be to conserve the interests of the cast-iron branch of the industry. America took up the work at once, and enlarged its committee to 67 members, all of whom were actively concerned in the manufacture or study of cast-iron in all of its branches. At the organization-meeting in Philadelphia, April 25, 1903, Mr. Walter Wood was elected chairman, and myself secretary; and, within a week thereafter, the sub-committees were appointed and became active at once. The scope of the work was naturally limited to those branches of the iron-casting in-

Jan 1, 1905

By Alan C. Noble

INTRODUCTION Forecasting of metal and mineral prices is a complex and hazardous undertaking. In order to accurately forecast prices, the complexities of both marketing and production must be modeled for each commodity. Even with the most detailed model, the economy may change unexpectedly, invalidating the forecast. Because of these factors, this chapter will not attempt to present specific methods for price estimation. It will, however, review the fundamentals of price forecasting as applied to planning and design of the final pit shell. Recognizing that no price estimate can be exact, sensitivity analysis will be reviewed as an approach to coping with these unknown variations.

Jan 1, 1979

By W. E. C. Eustis

1st. The fine iron ore is mixed with a sufficient proportion of fine coking coal, and is coked in any of the ordinary methods for making coke. The effect of this is to convert the iron oxide into sponge in such a shape that the usual trouble of oxidation is avoided. 2d. The resulting mixture of coke and sponge is melted down ill an ordinary cupola, the coke furnishing more than sufficient fuel for that purpose. I may briefly point out here that in the first place the iron is sponged, and this sponge, as is well known, contains no phosphoras or silicon when the reduction takes place at a low temperature; and in the second place this sponge is melted down in a cupola in which there is no zone of reduction for phosphorus or silicon, and that con . sequently the resulting iron should be free from both of these impurities. 3d. The liquid sponge, now carburized, is run into an open-hearth furnace, where the requisite degree of hardness or softness is obtained by adding some of the fine ore, and the usual dose of ferromanganese, I have merely given above the rough outlines of the prows, bat it is my intention, as early as possible, to bring the process more fully before the Institute.

Jan 1, 1881

By Keith E. Robinson, Brian Stimpson

INTRODUCTION In inclined sedimentary strata slope failure may occur by sliding along bedding and along a discontinuity or weak zone, as illustrated in Fig. 1. This mode of failure may be called 'bi-linear', as the failure surface is comprised of two linear or approximately linear segments. This type of failure has been suggested for the famous Frank Slide, Alberta, Canada (Cruder and Krahn, 1973) in which an estimated 90 M 5 tons (8.97 x 10 MN) of rock separated from Turtle Mountain and buried the town of Frank. Also, with the increasing depth of open pits and the construction of highways through inclined sedimentary strata this mode of failure is of major concern to the rock slope stability engineer. A computer program for calculating factors of safety for this slope failure mode is provided and includes the ability to vary shear strengths of potential slide surfaces, ground water elevations and wedge geometry. LIMITING EQUILIBRIUM MODEL The simple limiting equilibrium model used in the analysis is shown in Fig. 2. It is assumed that jointing is orthogonal to bed- ding and that the interface between the upper and lower wedges there- fore corresponds to a joint plane or planes. No shear strength is attributed to the interface so that the resultant force, P, from the upper wedge acts normally across the interface. The normal loads

Jan 1, 1983

By Charles A. Ashburner

[The statistics contained in this paper were collected for the United States Geological Survey and communicated to the Institute, by permission, prior to their publication in the report on the Mineral Statistics of the United States for 1887.1 The total coal-production of Alabama in 1887 was about 1,950,000 short tons, the spot-value of which, at the mines, was $2,535,000. The coal-regions of the State lie in the extreme southern part of the Appalachian coal-field, the northern part of which lies along the western New York-Pennsylvania State line; between these limits, New York on the north and Alabama on the south, portions of the

Jan 1, 1889

By G. W. Imholz

A number of interesting wells were drilled in north central Texas during 1940. The Shell Oil Company's Smith well in scc. 143, block I, H. and T. C. survey, Stonewall County, was completed for an initial production of 581 bbl. per day from the Mississippian limestone, with a total depth of 6065 ft. The same company's Patterson well, sec. 393, block D. H. and T. C. survey, Stonewall County, tested the Ellenburger limestone and was abandoned as a dry hole with a total depth of 6760 feet. In Nolan County the Tex-Harvey Oil Co. drilled a well in sec. 43, near the Tipton well, which was completed as a small producer in the Strawn section. The Tex-Harvey well tested this producing horizon but was abandoned as a dry hole with a total depth of 5210 feet. The Montour-Haggart well, sec. 184, block 2, H. and T. C. survey, Fisher County, tested the Strawn and was abandoned with a total depth of 5664 feet. The Georgian Oil Company's Blach, sec. 309, T. R. and L.. Shackelford County, encountered the top of the Ellenburger limestone at 4725 ft. After being plugged back to 3915 It. from a total depth of 4825 ft., the well tested 10 bbl, of oil per day and 300 bbl. of water. The W. I. Sothern No. 2 Carlisle well in sec. 293 was deepened to the Cambrian. The top of the Ellenburger was encountered at 6540 fcet. A wildcat well in Fisher County, the E. A. Stephenson-Maberry, apparently opened a new pool when the well encountered sand from 3298 lo 3302 ft. and was completed for 50 bbl. per day in the Cook sand horizon. In Jones County, the King Oil Company's Olsen well, sec. 158, B. B. B. and C. survey, extended the Avoca-Olander pool. The well was completed for 263 bbl. in 8 1/2 hr. from the Palo Pinto limestone, from 3298 to 3302 ft. Ungren-Frazier extended the Akard pool with No. I Akard, in the D. 'T. Bruce survey. The well was completed for 83 bbl. per day from the Cook sand, encountered from 2109 to 2126 feet.

Jan 1, 1941