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By R. J. Evans, A. G. Revesz

Silicon films have been grown by chemical reaction on (111) silicon substrates. The surfaces were examined by various microscopic and interfero-metric methods. Surface structures are classified into two groups depending on whether the angles between the bounding planes and the (111) surface are small (<3 deg) or large (> I0 deg). A layer-gvowth mechanism is postulated to explain the topography and the influence of growth parameters. Growth proceeds by lateral expansion of the (111) layers in (211) directions, thereby forming steps. The step edges are perpendicular to the direction of expansion and are thus along (110) directions. Step bunching md surface nucleation both play an important role in modifying the flow pattern and in the step regeneration. These are influenced ver?) much by impurities, especially oxygen. Although the growth is a result of a surface-controlled ga: reaction, it is very similar to growth from an impure solution. OVERGROWTH ("epitaxial growth") of silicon is important and widely used. During the past years several investigators have observed various topographical features or so-called faults on the grown films. A study of the surface morphology gives some insight into the growth mechanism. I) EXPERIMENTAL Silicon films have been grown on silicon substrates by a method described by Theuerer.&apos; Silicon is formed by reduction of SiCl, in hydrogen. The rate of incidence of SiC1, was varied between 5 x 10"6 and 2 x 10&apos;4 moles min-&apos; cm-&apos;. The mole fraction of Sic4 in the Hz-SiCL mixture was about 5 x X Both the rate of incidence and the mole fraction were calculated on the assumption that the Hz bubbling through the SiC1, reached equilibrium saturation. Assuming uniform velocity distribution, the linear velocity of the gas in the reactor tube was estimated to be 2 cm sec-l. The temperature of deposition was varied between 1070" and 1260°C. Chemically polished p-type silicon wafers of 20 to 100 ohm cm resistivity were used as substrates. These were within 1/2 deg of a (111) orientation. The thickness of the grown n-type film was determined by two methods: a) measurement of the depth of the p-n junction taking into account the junction shift due to diffusion, b) measurement of the traces of stacking-fault tetrahedra on the (111) plane.&apos; The agreement between the two methods was better than 20 pct. The rate of growth varied between 0.2 and 4.0 pmin-&apos;. The formed films were examined by reflection and light-section microscopy, and by multiple-beam interferometry. Phase-contrast illumination revealed height differences of about 30A. For measuring heights greater than 1 p a light-section microscope3 was used. The resolution by multipke-beam interferometry4 was between 50 and 100A. Crystallographic directions on the surface were determined by X-ray and from the orientation of etch pits and stacking faults as revealed by Dash etch (I part HI?, 3 parts HNOJ, and 12 parts CH3COOH). Some specimens have been investigated by electron microscopy. Platinum-shadowing and carbon-replica techniques were used to show the fine topography and reflection diffraction to determine the structure of the grown layers. 11) RESULTS The topographical features can be classified into three groups. he first group is comprised of fine ridges (striations). The second group consists of structures, which are bounded by planes making angles of less than 3 deg with the (111) surface. They are, therefore, vicinal planes. Structures which closely resemble growth or etch pyramids from the third group would normally be bounded by perfect low-index crystallographic planes. In this case they are deformed. The angles between the bounding planes and the (111) surface are generally larger than 10 deg. The fine ridges are present, even on the smoothest surfaces, as shown in Fig. 1. They are along a (110) direction. The height differences could not be resolved with interferometric techniques. The basic characteristic structures of the second group are depressions and hillocks. These are bounded by three planes, two of them with larger slopes than the third one. The edges between the planes, as projected to the (111) surface, point in (211) directions. Various habits of these structures are shown

Jan 1, 1964

By J. de la Vergne, L. O. Cooper

The hydrostatic steel mine shaft liner (HSL) Provides a permanent wall lining for drilled shafts. It is watertight and suitable for bad ground conditions. After a shaft has been drilled to its full depth, the HSL is lowered into it and secured in place with cement grout. The liner consists of a cylindrical steel shell usually reinforced with exterior stiffening rings. The shell is basically designed for compressive strength and the rings are provided to give the shell added resistance to buckling. There are no published standards for the correct procedures to design an HSL. This paper gives a method that appears logical. A design solution can be complex with increased opportunity for error. This paper presents simple formulas to produce sufficient accuracy for construction design. Two new concepts are presented, referred to as transition pressure and critical pressure. An example demonstrates use of the formulas and concepts presented. To facilitate comprehension and use of the formulas, Greek letters are avoided and most of the English alphabet symbols used refer by association to their definitions. An appendix shows derivation of the formulas.

Jan 1, 1984

By G. B. Walker, S. A. Falconer, S. J. Swainson, H. H. Vogel

During the past few years much interest and attention has been focused on a relatively new method of ore concentration, which utilizes the principles of sink and float and employs as the heavy medium a suspension in water of a finely ground solid, such as galena or ferrosilicon. Although a relatively recent development, much progress has already been made in applying heavy-media separation processes to a considerable number of ores. Eight plants in this country and abroad are now treating approximately 10 million tons of ore annually by heavy-media separation (sink-float) processes, including lead-zinc, lead, iron, garnet, tin and tungsten. At the annual meeting of the A.I.M.E. in 1941, three interesting papers (unpublished) dealing with heavy-media separation (sink-float) processes of ore concentration as practiced in four commercial units in the United States were presented by Victor Rakowsky, Grover Holt, Elmer Isern and Robert Ammon. These papers gave an excellent exposition of the principles of sink and float, as well as the operating practice in two iron-ore-beneficiation plants, the Harrison and the Merritt, of Butler Brothers, in Minnesota; the Central mill of the Eagle Picher Mining and Smelting Co.; and the Mascot mill, of the American Zinc, Lead and Smelting Co. Augmented by pictorial descriptions and a working model demonstrating the processes, these papers evoked a great deal of interest and discussion. In fact, in reporting the high lights of the meeting in the April 1941 issue of Mining and Metallurgy, Professor Taggart made the statement that " preconcentration by heavy suspension was Miss A.1.M.E 1941 so far as milling is concerned." Although to date the greatest application of heavy-media separation from the tonnage point of view has been for the treatment of lead, zinc and iron ores, these processes have a much wider field of usefulness. In this regard, it is to be noted that recently new heavy-media separation plants for treating cassiterite ore and garnet ore have been placed in successful operation. Moreover, numerous other types of ores have been found to respond well to these processes when tested on a semi-commercial scale, and it is expected that in the near future a considerable number of new plants will be erected. In view of the fact that heavy-media separation processes offer such attractive possibilities, particularly now, when the mining industry is being called on for an even larger production than ever before has been attempted, despite shortages of labor and supplies, it was felt that a description of some of the successful separations that have been worked out during the past year in the Ore Dressing Laboratory of the American Cyanamid Co. on a variety of ores of strategic importance would be of interest. The purpose of this paper, therefore, is to present the essential data relating to investigations of heavy-

Jan 1, 1943

By G. B. Walker, S. J. Swainson, S. A. Falconer, H. H. Vogel

During the past few years much interest and attention has been focused on a relatively new method of ore concentration, which utilizes the principles of sink and float and employs as the heavy medium a suspension in water of a finely ground solid, such as galena or ferrosilicon. Although a relatively recent development, much progress has already been made in applying heavy-media separation processes to a considerable number of ores. Eight plants in this country and abroad are now treating approximately 10 million tons of ore annually by heavy-media separation (sink-float) processes, including lead-zinc, lead, iron, garnet, tin and tungsten. At the annual meeting of the A.I.M.E. in 1941, three interesting papers (unpublished) dealing with heavy-media separation (sink-float) processes of ore concentration as practiced in four commercial units in the United States were presented by Victor Rakowsky, Grover Holt, Elmer Isern and Robert Ammon. These papers gave an excellent exposition of the principles of sink and float, as well as the operating practice in two iron-ore-beneficiation plants, the Harrison and the Merritt, of Butler Brothers, in Minnesota; the Central mill of the Eagle Picher Mining and Smelting Co.; and the Mascot mill, of the American Zinc, Lead and Smelting Co. Augmented by pictorial descriptions and a working model demonstrating the processes, these papers evoked a great deal of interest and discussion. In fact, in reporting the high lights of the meeting in the April 1941 issue of Mining and Metallurgy, Professor Taggart made the statement that " preconcentration by heavy suspension was Miss A.1.M.E 1941 so far as milling is concerned." Although to date the greatest application of heavy-media separation from the tonnage point of view has been for the treatment of lead, zinc and iron ores, these processes have a much wider field of usefulness. In this regard, it is to be noted that recently new heavy-media separation plants for treating cassiterite ore and garnet ore have been placed in successful operation. Moreover, numerous other types of ores have been found to respond well to these processes when tested on a semi-commercial scale, and it is expected that in the near future a considerable number of new plants will be erected. In view of the fact that heavy-media separation processes offer such attractive possibilities, particularly now, when the mining industry is being called on for an even larger production than ever before has been attempted, despite shortages of labor and supplies, it was felt that a description of some of the successful separations that have been worked out during the past year in the Ore Dressing Laboratory of the American Cyanamid Co. on a variety of ores of strategic importance would be of interest. The purpose of this paper, therefore, is to present the essential data relating to investigations of heavy-

Jan 1, 1943

By G. B. Walker, S. J. Swainson, S. A. Falconer

DURING the past few years much interest and attention has been focused on a relatively new method of ore concentration, which utilizes the principles of sink and float and employs as the heavy medium a suspension in water of a finely ground solid, such as galena or ferrosilicon. Although a relatively recent development, much progress has already been made in applying heavy-media separation processes to a considerable number of ores. Eight plants in this country and abroad -are now treating approximately 10 million tons of ore annually by heavy-media separation (sink-float) processes, including lead-zinc, lead, iron, garnet, tin and tungsten. At the annual meeting of the A.I.M.E. in 1941, three interesting papers (unpublished) dealing with heavy-media separation (sink-float) processes of ore concentration as practiced in four commercial units in the United States were presented by Victor Rakowsky, Grover Holt, Elmer Isern and Robert Ammon. These papers gave an excellent exposition of the principles of sink and float, as well as the operating practice in two iron-ore-beneficiation plants, the Harrison and the Merritt, of Butler Brothers, in Minnesota; the Central mill of the Eagle Picher Mining and Smelting Co.; and the Mascot mill, of the American Zinc, Lead and Smelting Co. Augmented by pictorial descriptions and a working model demonstrating the processes, these papers evoked a great deal of interest and discussion. In fact, in reporting the high lights of the meeting in the April 1941 issue Of MINING AND METALLURGY, Professor Taggart made the statement that "preconcentration by heavy suspension was Miss A.I.M.E. 1941 so far as milling is concerned." Although to date the greatest application of heavy-media separation from the tonnage point of view has been for the treatment of lead, zinc and iron ores, these processes have a much wider field of usefulness. In this regard, it is to be noted that recently new heavy-media separation plants for treating cassiterite ore and garnet ore have been placed in successful operation. Moreover, numerous other types of ores have been found to respond well to these processes when tested on a semi-commercial scale, and it is expected that in the near future a considerable number of new plants will be erected. In view of the fact that heavy-media separation processes offer such attractive possibilities, particularly now, when the mining industry is being called on for an even larger production than ever before has been attempted, despite shortages of labor and supplies, it was felt that a description of some of the successful separations that have been worked out during the past year in the Ore Dressing Laboratory of the American Cyanamid Co. on a variety of ores of strategic importance would be of interest. The purpose of this paper, therefore, is to present the essential data relating to investigations of heavy-

Jan 1, 1943

By Dwight K. Smith

A new pozzolanic composition has been developed for cementing oil wells where moderate to high temperatures prevail. This material is an entirely different concept to other oil well cementing materials, such as portland cements, cements containing additives, or liquid resins. Its characteristics are such that it is not, at present, recommended for use at temperatures less than 140º F. It can he either accelerated or retarded across a wide range of well conditions. This new cement is composed of a pozzolanic material, hydrated lime, and a chemical activator to give it early initial strength. This material can be used in wells from 6,000 to 18,000 or more feet where temperature conditions are similar to those along the Gulf Coast. This cement, when set, has no soluble portion subject to leaching or any compounds that should be attacked by sulfate waters or brines. For this reason, it should be permanent when placed adjacent to formations carrying any type of fluid. The compressive strengths in 24 hours are more than adequate for wells where temperatures are 140°F and higher. These values ore in excess of many other types of cementing composition presently in use in the field. This pozzolanic composition does not retrogress in strength at high temperatures as do some other types of cementing materials. The slurry weights of this material will vary slightly according to the specific gravity and water requirements of the pozzolnn itself. The materials covered herein will mix from 13.5 to 14.3 lb/gal, and will have a waiting-on-cement time comparable to other materials used under the same conditions. Economically speaking, this composition is less expensive than either portland cements or retarded cements presently being used under deep well conditions. INTRODUCTION Pozzolans are siliceous material which, though not cementitious in themselves, contain constituents which at ordinary temperatures will combine with lime in the presence of water to form compounds which have a low solubility and possess cementing properties. The use of pozzolanic materials dates back many hundreds of years and both the ancient Greeks and Romans were aware that certain volcanic deposits, if finely ground and mixed with lime and sand, yielded a mortar which possessed special properties. Generally, the early strengths of such materials were rather weak and were considered insufficient for modern commercial usages. Pozzolanic materials have been used extensively with portland cement in mass concrete to obtain special properties. In recent years, large quantities of certain pozzolanic materials have been used successfully admixed into portland cements for oil well cementing. Pozzolans, being reactive silicates, will combine with the free lime that is an inherent component of set portland cements and thereby. becomes cementitious themselves. POZZOLANS FOR OIL WELL CEMENTING There are many types of pozzolans, some of which are more reactive than others. The quality of the pozzoIan depends on the degree of reactivity, chemical composition, fineness, and other less well understood factors. Some of the more widely accepted pozzolans are those classified as fly ashes, while others are certain materials of volcanic origin. pozzolans which require large vol-

Jan 1, 1957

By Peter J. Szabo

Introduction This is the Pacific Rim. Nearly three fourths of the world&apos;s population live on or near its border. In the recent past, on any given day, one could find traversing its„ borders pirates, smugglers, gunrunners, missionaries, slave traders, tourists, and businessmen. If one were not too observant, he would notice that over the last several years the ocean traffic in the Rim has pretty much stayed the same--Polynesian outriggers, passenger ships, general cargo vessels, ore carriers, and oil tankers. If he were to look a little closer, he would notice some coal colliers. A still closer look would reveal that most of them were hauling metallurgical coal destined for the steel mills of Japan, Taiwan, or Korea. If his senses were keen, he would observe that not only were the number of colliers increasing dramatically, but also that a relatively new cargo was being carried to those countries as well as additional areas in the Pacific Rim., This new cargo thermal coal holds the promise of not only exceeding the metallurgical coal trade, but significantly cutting into and decreasing the already vast oil tanker business throughout the Pacific Rim. The high price of crude oil as a result of the oil embargo in the Middle East in 1973-74 has forced the Pacific Rim countries to convert to coal, and as a result, the coal resources of the Rim are being exploited at an ever-increasing rate. Although coal produced outside the Pacific Rim does enter its borders for ultimate consumption from such places as South Africa and the East Coast of the United States, the vast majority of thermal coal that will enter this booming market place will be sourced from countries within the Pacific Rim. Accordingly, this paper will provide an overview of those sources with particular emphasis on the non-communist block nations. This is not to say that countries such as China and Russia will not be players in the Pacific Rim thermal coal arena, but that -most consuming countries in the Rim are basing the majority of their near-term sourcing requirements from countries that provide a stable source of supply. Pacific Rim Coal Resources Figure 1 is a map of the Pacific Rim countries and identification of major coal resource locations within its border. Going in a clockwise direction, the following countries will be the major suppliers of thermal coal through the year 2000: Australia, Indonesia, China, Russia, Alaska (U.S.), Canada, United States (Utah, Colorado, Wyoming, Montana), and Colombia, South America. Other countries such as New Zealand, Malaysia, Philippines, Korea, etc., will play a role in supply, but compared to the ones previously mentioned, will only have a minor impact. When one looks at the vast stretch of ocean that separates the sourcing countries from the consuming countries (Japan, Korea, Taiwan, Hong Kong, Singapore, etc.), one realizes that costs of transportation will play a significant role in determining which countries and in what quantities coal will be purchased. Figure 2 for comparative purposes, shows

Jan 1, 1982

September 20, 1917. As this meeting terminates the year&apos;s agreement under which the Engineering Foundation has appropriated its income to the National Research Council, a brief summary of what has been accomplished seems called for. The Research Council was organized Sept. 19, 1916. The Executive Committee was appointed at that meeting; since that date two other meetings of the Council have been held, one in Boston, on Nov. 13 and 14, the other in Washington on April 19. During the intervals between the meetings of the Research Council, the Executive Committee has conducted all of the business of the Council. There have been 29 meetings of the Executive Committee, 13 in New York up to the first of May, 15 in Washington subsequently, and one in Boston. The meetings in New York were devoted to the organization of the Research Council and especially to appointment of committees. At the outset, the Council had no very clear idea of the way in which it was to organize; there were several other groups of scientific men at work, among them, the Research Committee of the American Association for the Advancement of Science and the Engineering Committee of the Advisory Commission to the Council of National Defense. Time was spent in straightening out these two principal complications, both of which were satisfactorily adjusted. The upshot of these negotiations is to leave the Research Council as the only representative, national body of research men, assisting the Government. During the period up to May, the Executive Committee in New York selected carefully the personnel of some 25 principal committees, and of a large number of sub-committees; so carefully were these chosen that of the entire number, several hundred, there have been only one or two declinations. Some of the important steps in the development of the Research Council are the establishment of the Military Section, composed. of the members of the Council connected with the Government and resident in Washington. This Section put the Research Council into close contact with the most important officials of the Army and Navy. From it has grown the Washington office of the Council, and the recognition of the Research Council as the "Department of Science and Research of the Council of National Defense; " and the establishment of the Washington office after the Council of National Defense had officially recognized the Research Council. About this time Dr. Hale, Chairman of the Council, appointed Dr. Millikan to be Vice-Chairman to represent the Council in Washington, and Dr. Millikan has since then been in charge of the work of the Council. At the request of the Secretary, Dr. Millikan has prepared a brief report of some of the work of the Research Council during its first year, which is appended to this report. It shows that the Research Council has been active in much of the important work. under way in our preparations for war, and that it has rendered effective services to the Government.

Jan 12, 1917

CONTENTS PAGE CARMICHAEL, NORMAN, and KIDDIE, JOHN.-Development of Mine Transportation in Clifton-Morenci District. Discussed by Norman Carmichael, Charles Legrand, B. B. Gottsberger 1 BARER, THOMAS C.-Fresnillo - Glory-hole Mining Practice. Discussed by Charles A. Mitke, B. B. Gottsberger, E. R. Thomas, Enoch Perkins..: 3 BRADLEY, P. R.-Estimation of Ore Reserves and Mining Methods in Alaska Juneau Mine. Discussed by R. M. Raymond, A. H. Rogers, Enoch Perkins, H. G. Moulton 6 BIRCH, STEPHEN.-Geology and Mining Methods of the Kennecott and Beatson Mines. Discussed by R. M. Raymond, Alan M. Bateman, Enoch Perkins 8 LEES, CHARLES E.-Mining Methods and Costs at the Iron Cap Copper Co., Copper Hill, Ariz. Discussed by A. L. Walker, A. Neustaedter 10 BELL, CHARLES N. -Mining Methods of the Telluride District. Discussed by Charles S. Hurter 10 Development of Mine Transportation in Clifton-Morenci District Discussion of the paper of NORMAN CARMICHAEL and JOHN KIDDIE, presented at the New York Meeting, February, 1924, and issued, as. Paper No. 1310-M, with MINING AND METALLURGY, March, 1924. NORMAN CARMICHAEL.-We realized the objections too the gable-bottom car, but were almost forced to its adoption by the same reasons that caused us to retain the 20-in. gage. To use another car would have meant a vast number of changes, for our transportation system was quite extensive; all mine chutes and ore bins were arranged for that car. Had we been laying out, new works, many of our decisions would have been different. MEMBER.-If you were planning it now, would you not put in box bottom cars with a rotary dump? NORMAN CARMICHAEL.-We surely would. One objection to the gable-bottom car is the spill. No, matter how carefully the cars are kept up,: there is always leakage and spill. The cost of keeping and maintaining the cars in a good state of repair, so as to keep that loss at a minimum, is not necessary for a box-bottom car.

Jan 6, 1924

By Robert M. Asimow, Bisuddhi Riddhagni

THE use of back-reflection Laue photographs for crystal orientation is standard in many research projects. The time required for the orientation of any given crystal depends largely on luck and the skill of the investigator. In any case, where large numbers of crystals are used, this time can be quite considerable when the standard methods involving a Greninger chart and Wulff net are employed. For this reason the technique described below was developed. This new procedure applicable for cubic crystals (without preparation of new charts) largely eliminates the skill and luck factors and makes possible the determination of orientation in minutes. The procedure works in the following way: the Laue photograph is examined and arbitrarily an important hyperbola is picked out. An important hyperbola is defined as one which contains some spots through which several hyperbolas pass. Such a hyperbola inevitably corresponds to a low-index zone axis. The angles between the reflection planes causing all the spots on this hyperbola can be read directly from a Greninger chart in the usual manner. If the hyperbola contains more than five spots, these interplanar angles will positively identify the zone axis and the indices of each of the reflecting planes. However, initially since neither the zone axis nor the Miller indices of a diffraction spot are known, there are a very large number of possibilities that must be considered. Using tables of interplanar angles to check out every possibility would be quite tedious, so that this approach is not generally used. Instead, various poles are plotted on a stereographic projection. In the cubic system, however, it is possible to plot out once and for all the angles between all planes of a particular zone axis up to some upper limit of Miller indices. This has been done for all low-index zone axes in Fig. 1. Given these charts, it is quite a simple matter to identify the spots of the unknown hyperbola. All that is necessary is to plot the angles read off the Greninger chart to the same scale as Fig. l(b) on a strip of paper. Then this strip can be slid along each zone axis of Fig. l(a) until a good fit is obtained. Once this is accomplished, the Miller indices of each spot are given and thus the orientation problem is solved. To check, it is possible to pick a second hyperbola and see whether a compatible solution is obtained. This is most conveniently done by picking for the second hyperbola one that contains a spot common with the first. If the specimen axis is chosen parallel to the incident X-ray beam, then usually the [ loo] hyperbola will appear on the film as one of the more important hyperbolas and consequently will be either chosen initially or as a check. Using the [100] hyperbola, after the (001) or (011) spots have been identified, the latitude and longitude of the specimen axis can be read directly from the Greninger chart so that it is unnecessary to use a Wulff net for the entire orientation procedure. This makes the operation not only quicker but more accurate. Of course, if neither the first nor second hyperbolas correspond to [loo] then a third hyperbola can be chosen.

Jan 1, 1967

By Forbes K. Wilson

Dick Hunt is known for having said, "Ore bodies are found but mines are made." This was certainly true of the Ertsberg-it was stumbled upon, literally, by a group of mountain climbers, but to develop it into a mine took 12 years of concerted effort. For more than a century, explorers had attempted to penetrate the jungles of New Guinea and climb the snow-covered Mt. Carstensz, named for a Dutch navigator who first saw it in 1620. But the first to succeed was the Colijn expedition which reached the 5030-m (16,500-ft) pinnacle in December 1936 after starting out from the south coast57 days earlier. Members of that expedition were A. H. Colijn and Jean Jacques Dozy, employees of Shell Oil Co., and Lt. Wissel, a pilot in the Royal Dutch Navy.

Jan 6, 1977

By W. David Leyshon

This paper compares the general characteristics of Florida phosphate rock for the manufacture of fertilizers and phosphoric acid. The subjects covered are relative reactivity for superphosphate manufacture and various properties of the rock for use in phosphoric acid production, including gypsum filterability, sulfuric acid consumption, foaming, relative cor-rosiveness, chemical composition, and others. Comprison will include rocks of North Africa, the western U.S., and other locations. This paper reviews some of the important properties of phosphate rock, giving particular attention to a comparison of Florida phosphate with some of the major phosphates produced in the world. It also discusses some of the techniques available for evaluatine Phosphate. rock for phosphoric. acid and fertilizer use. The use of Florida rock outside the U.S. has been increasing steadily, evidence in itself of certain desirable properties of this rock. Table I is a list of the major producers and exporters of phosphate rock as of 1965. Florida, meaning in this case Central Florida, was the largest producer of phosphate rock and the largest exporter of rock. Of a total world production estimated at 60 million tons, about 50 million tons were produced during 1965 by the areas listed in Table I. One major producing area omitted from Table I and from subsequent evaluations in this paper comprises Nauru, Ocean, and Christmas Islands, whose output totaled about three million tons in 1965. This phosphate is marketed entirely by the British Phosphate Commissioners, primarily in Australia and New Zealand, and does not get into the world market elsewhere to a significant degree at the present time. South Africa, Egypt, Israel, and North Vietnam also produce lesser quantities of rock for the international market, and these materials are also excluded from this review. The phosphate industry is now seeing the introduction of several new areas that will be significant factors in the rock market in the future. The North Carolina and North Florida areas each have capacity at present or in the near future for producing about three million tons per year. The Djebel Onk mine in Algeria has a potential of about 800,000 tons per year. In addition, announcements have been made of significant development of deposits in Peru and in the Spanish Sahara, and sizable expansions are planned in several of the existing areas that are now of minor importance. Competition for the rock market appears to be increasing so that more attention will probably be paid to evaluating phosphates available from different areas. It is not possible here to go into all the properties of even a few of the materials listed in Table I. However, it is practical to discuss some comparative properties important for making phosphoric acid and fertilizers, and to touch on the techniques used for the evaluation of various phosphate rocks. Table II gives typical analyses of the major phosphate rocks available in the world as of 1965. There is, of course, an inherent danger in labeling any analysis as typical, but it appears that variations between two samples of rock within one given area are generally less than between two samples from different areas. The analyses listed were compiled from several years of data so they may not be representative of the present output of any particular area. The range of grades represented by these analyses goes from 66 BPL for Gafsa rock to 85 BPL for Kola

Jan 1, 1968

By C. W. Schulties, W. J. Mallio, L. J. Petrovic, J. A. L. Campbell

Roof control comprises about 35% of direct and indirect underground mining costs. In addition, difficulties in estimating roof control costs for new areas lead to the greatest uncertainties when negotiating coal contracts. And obviously, coal cannot be mined if the roof can&apos;t be held. Accordingly, there are strong incentives to attack this problem on as many fronts as possible. One successful geological modeling technique for predicting future roof conditions was recently applied at Peabody Coal&apos;s Simco mine No. 5, located in Coshocton, Ohio. Benefits derived from it included: - A better identification of areas where poor safety conditions may be encountered. - Improved roof control cost estimates for contract negotiations. - Estimates of time-duration while mining in bad roof areas. - Labor and materials cost predictions in an existing mine. - Productivity increases through prior knowledge of areas to avoid.

Jan 10, 1975

By Brij M. Moudgil

Disposal of fine coal refuse is one of the major technical problems which could adversely affect growth and development of the coal industry. At present one of the most: common methods for disposal of fine coal refuse slurry involves impounding the slurry behind dams. However meeting new federal and state government regulations for building, maintaining and reclaiming these impoundments in addition to terrain and space considerations render this technique to be only marginally competitive with other disposal methods. The coal industry has been actively engaged in developing alternate disposal techniques which are economically feasible and environmentally acceptable. A review of coal refuse disposal problem and current refuse disposal practice both in the eastern and western coal fields is presented. Various promising techniques being developed for economical and safe disposal of fine coal refuse slurry are also discussed.

Jan 1, 1980

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) The governing body of the Imperial College of Technology, London, S. W. (Royal School of Mines), will shortly proceed to the appointment of a Professor of Metallurgy. This important Chair has been filled in the past by such eminent metallurgists as John Percy, Sir William C. Roberts-Austen, and others. Inquiry has been received at the office of the Institute for an engineer to examine a mica, deposit in one of the New England States. The position of converter blower at. a side-blow Bessemer steel casting plant is vacant.

Jan 4, 1913

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the first half of March: James C. H. Ferguson, San Francisco, Cal. Capt. A. F. Lucas, Washington, D.C. Henry Adams, Stamford, Conn. Dexter P. Cooper, New York, N. Y. H. A. Wheeler, St. Louis, Mo. L. D. Moore, Chatham, N. J. John M. Sherrerd, Easton, Pa. Hennen Jennings, Washington, D. C. R. T. White, formerly General Manager of the Braden Copper Co., Chile, is to take charge of a copper company in Caucasus, South Russia.

Jan 4, 1914

By John F. Myers

Since the art of comminution has lain practically dormant for many years, it is very interesting that R. T. Hukki approaches the subject with a new concept. One is reminded of the research carried on by A. W. Fahrenwald of Moscow, Idaho, a few years ago. Fahrenwald mounted a steel bowl on a vertical shaft. The balls and ore placed in the bowl were rotated at fast speeds, thus simulating the supercritical speeds used by Hukki. The rolling action of the balls against the smooth shell liner has pretty much the same effect. The action is horizontal in one case and vertical in the other. Both researchers report good grinding activity.

Jan 8, 1958

By George M. Bouton, Lawrence Ferguson

The experiments described in this publication were inspired by the Bell System&apos;s large interest in lead-alloy sheathed cables and by the wide range of fatigue and corroding conditions to which they are sometimes subjected in service. The first experiments consisted of operating specimens of lead + I per cent antimony telephone cable sheath alloy in a fatigue test while they were immersed in water taken from a manhole. Because of many published reports concerning corrosion-fatigue phenomena of various metals and alloys, a reduction in fatigue life was expected(1)2 Instead, however, the fatigue test ran on for many times the normal number of cycles an4 was finally stopped without failure. Because of this, the experiments were broadened to include the effect of many media on the fatigue properties of four lead alloys over a wide range of testing speeds and strains. One material, a viscous tacky polymerized isobutylene3 used in

Jan 1, 1945

By Walter Kauenhowen

Germany&apos;s crude oil production during 1935 totaled 3,007,711 bbl., an increase of 36.6 per cent over the 2,202,214 bbl. produced in 1934. The Nienhagen-Haenigsen field furnished 77 per cent of the total 1935 production. Cumulative production figures for Germany&apos;s two most important oil fields, Wietze and Nienhagen, show that during the period from 1872 to the close of 1935 the Wietze field produced 13,325,536 bbl. and the Nienhagen field 9,340,870 bbl. Table 1 gives statistics of German production since 1928, arranged both by fields and by oil provinces. Fig. 1 demonstrates the production of the various German fields since 1890. New Fields Discovered During 1935 five new fields came into production. The first of these, the Moelme-Hoheneggelsen field near Hanover, was opened up in April. This region has been sporadically drilled for oil since 1882, but not until 1935 was production on a commercial scale obtained. The oil comes from Mesozoic sandstones on the flanks of a shallow salt plug. Also during April, oil was found in commercial quantities in the Rhine valley at Forst, near Bruchsal. Tertiary and Mesozoic sandstones cut by faults of the Rhine Graben form the reservoir structures in this area. In July a wildcat well drilled on the Fallstein structure, a broad Triassic anticline near Halberstadt, came in as a producer from Permian (Zechstein) dolomite. In September commercial oil mas found at Gifhorn, near Braunschweig, in Wealden sandstones associated with a shallow, geophysically discovered salt plug. During the same month production was obtained at Heide, in Holstein, from the Permian Rotlie-gendes formation, in a structural high on which oil seepages have been known for years. Drilling Activities Published information indicates that during 1935 drilling totaled 574,000 ft., as compared with 436,000 ft. in 1934; 233,000 ft. in 1933 and 151,000 ft. in 1932. The German Government is subsidizing wildcat

Jan 1, 1936

By Walter Kauenhowen

Germany&apos;s crude oil production during 1935 totaled 3,007,711 bbl., an increase of 36.6 per cent over the 2,202,214 bbl. produced in 1934. The Nienhagen-Haenigsen field furnished 77 per cent of the total 1935 production. Cumulative production figures for Germany&apos;s two most important oil fields, Wietze and Nienhagen, show that during the period from 1872 to the close of 1935 the Wietze field produced 13,325,536 bbl. and the Nienhagen field 9,340,870 bbl. Table 1 gives statistics of German production since 1928, arranged both by fields and by oil provinces. Fig. 1 demonstrates the production of the various German fields since 1890. New Fields Discovered During 1935 five new fields came into production. The first of these, the Moelme-Hoheneggelsen field near Hanover, was opened up in April. This region has been sporadically drilled for oil since 1882, but not until 1935 was production on a commercial scale obtained. The oil comes from Mesozoic sandstones on the flanks of a shallow salt plug. Also during April, oil was found in commercial quantities in the Rhine valley at Forst, near Bruchsal. Tertiary and Mesozoic sandstones cut by faults of the Rhine Graben form the reservoir structures in this area. In July a wildcat well drilled on the Fallstein structure, a broad Triassic anticline near Halberstadt, came in as a producer from Permian (Zechstein) dolomite. In September commercial oil mas found at Gifhorn, near Braunschweig, in Wealden sandstones associated with a shallow, geophysically discovered salt plug. During the same month production was obtained at Heide, in Holstein, from the Permian Rotlie-gendes formation, in a structural high on which oil seepages have been known for years. Drilling Activities Published information indicates that during 1935 drilling totaled 574,000 ft., as compared with 436,000 ft. in 1934; 233,000 ft. in 1933 and 151,000 ft. in 1932. The German Government is subsidizing wildcat

Jan 1, 1936