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By James M. Link

The design and construction of cross-country pipelines for fluids such as crude oil appears relatively simple compared to the complex problems encountered in slurry systems. Considerable effort has been expended in hydraulic research laboratories in an attempt to improve the understanding of slurry behavior. This effort has been rewarded with considerable success and is best illustrated by the large number of slurry systems now planned or under construction. However, slurry transport in pipelines is still, in many instances, more of an art than a science. In order to minimize the risk factors in the construction and operation of large scale slurry systems, studies are frequently conducted in pilot scale test loops such as the one at the Colorado School of Mines Research Institute. The pilot scale projects are designed to provide the basic engineering data necessary to design slurry transport pipeline systems. Usually three slurry solid concentrations are pumped at various line velocities and optimum slurry densities and velocities are determined. Critical velocities, friction head losses, power requirements, and so forth, are also determined from measurements and calculations. Wear tests are also strongly recommended and anticipated pipe wear rates in inches per million tons of solids reported.

Jan 11, 1972

By Thomas Leonard Watson

In a paper read by title at the Washingtoil meeting of the Institute,' May, 1905,I discussed at considerable length the geological relations, mode of occurrence, and the genesis of the lead- and zinc-ores of the VirginisTennessee region. The present paper treats of the purely ecorlomic phases of the zinc-ores of the district,—such as methods of mining the ores, their preparation and treatment. The Albemarle coullty mines and plant were discussed in the paper referred to above, and mill not be considered here. Methods of Mining. Until very recently the mining of lead- and zinc-ores in Virginia mas limited wholly to the surface-belt of weathering. The mode of occurrence and the character of the ores to be mined were such as to demand the employment of niethods used in mining secondary concentrated ores. Accordingly, a system similar to that practiced in mining brown iron-ores was employed, being modified to meet the changed conditions. Oxidized or Soft Ores.—Up to the present time practically all the ore mined in the Virginia district has been of the oxidized or soft type;—the silicate, calamine, and the carbonate, smith-sonite; largely the former, which has been localized and concentrated at only slight depths below the surface. Because of the extreme irregularity with which the limestone weathers when stripped of the overlying residual clay, it presents a roughened surface of large and small irregular " chimneys"

Jan 1, 1907

By Milton E. Wadsworth, J. Brent Hiskey

INTRODUCTION Fifteen years ago a distinguished electrochemist referred to electrochemistry as an "underdeveloped science " In the article in question, Professor Bockris (1) stated that many areas of.natura1 phenomena and applied technology are not perceived as being electrochemically based At that time, this was especially true for much of non-ferrous extractive metallurgy and was a particularly accurate description of hydrometallurgy During the last decade, there has been considerable advancement in applying the theory of electrochemistry to our know1 edge of hydrometallurgical processes and in understanding the mechanisms of underlying electrode reactions. Impressive as these advances are, there is still a growing need for electrochemical research of mineral systems and electrochemical engineering to apply this work in practical situations In a broad sense electrochemistry is defined as the physical chemistry of ions in solution and of phenomena which occur at the electrified interface. Bockris and Reddy (2) refer to electrochemistry as being divided into two fundamental domains, ionics and electrodics ionics is restricted to the behavior of ions in solutions, examples being many familiar redox processes Electrodics represents the main part of electrochemistry, and is the study of charged interfaces and the conditions governing charge transfer reactions across them. Considering hydrometallurgical applications, electrodics suggests the following relationship for a conducting solid (bulk or surface)

Jan 1, 1981

By Paul D. Merica

Jan 1, 1937

By C. D. Looker

Common salt is mentioned in the most ancient writings as an important article of diet. It is fairly certain that it was used by men and animals long before the dawn of civilization. Its presence in natural springs has often been the determining factor in colonization; wars have been fought for possession of salt deposits; trade routes have been established expressly for the purpose of traffic in salt. Naturally this led men into adventures and discoveries that altered history and advanced civilization. In the early days the uses for salt were few and the methods of manufacture were crude and the purity low when compared to salt of the present day. Then the salt came largely from springs, shallow wells or the ocean, while today deep wells must be drilled to the natural brines or beds of rock salt and spacious shafts sunk so that the ancient deposits may be made to yield their supply of stored mineral. Mining and Purification The quantity of available salt seems inexhaustible. It occurs in practically every country of the globe. About 20 million tons is produced and consumed annually in the world. Of this amount about 7 million tons is produced in the United States; 13/4 million tons of rock salt, 2 1/4 million tons as evaporated salt and 31/2 million tons in brine used in the chemical industry. Mined rock salt is used in its natural state without purification. It is classified for the trade by crushing and screening. The average purity of rock salt mined in the United States is about 98.3 per cent pure sodium chloride1. The usual impurities are gypsiferous shale, anhydrite and silica, with traces of potassium, magnesium and calcium compounds. Refined or evaporated salt is made by crystallizing the salt from brine in open pans or vacuum pans. A comparatively small amount of salt is made from ocean water or the brines of inland lakes or seas, sometimes by solar evaporation. By far the larger amount of brine is obtained by drill-

Jan 1, 1938

By M. H. Forester, John D. Cooner

ALTHOUGH the unmined anthracite will last for approximately 150 years, most of the thicker and cleaner coal beds have been almost entirely first-mined and pretty well robbed, leaving much of the present and future production to come from thin and dirtier beds. Herewith is a section of one of the dirty beds being mined in the Wyoming region [ ] This section shows that 45.8 per cent of the bed is made up of impurities and that the 45 in. of coal in the bed is in five benches, the thickest of which is 19 in. In some localities of the anthracite region there are 14 beds of minable coal. Orderly and proper mining of the coal makes it necessary to rob or second-mine--almost all beds have already been first-mined-in sequence from the top downward. Therefore the robbing of the few remaining portions of the thicker and cleaner beds is in many instances being held up by the mining of the overlying thin and dirtier coal beds. Impurities Impurities consist of fire clay, slate, rock, and bone. The latter, which is black, contains 40 to 60 per cent carbon and often resembles good coal. In some beds there are also bands of "blue" coal, which, as the name implies,

Jan 1, 1950

By J. T. Burwell

As is well known, the alloys of iron containing 18 ± per cent chromium, 8 ± per cent nickel and less than 1.2 per cent carbon exhibit the same allotropic modifications as iron. The face-centered cubic or gamma phase is stable at high temperatures and the body-centered cubic or alpha ferrite is presumably stable at room temperature. The transformation from the gamma phase to the alpha phase in alloys of the above composi-tion (18-8 or stainless steel) is sluggish; even moderately rapid cooling permits the retention of the gamma phase. Cold-work, however, causes the transformation from gamma to alpha to occur at room temperatures. It is difficult, nevertheless, to induce complete transformation regardless of the method of cold-working. Since metallographic polishing is very effective in transforming the surface austenite to ferrite, as indicated by the magnetic studies of Buehl and Wulff, 1 it was decided to investigate the phenomenon by electron diffraction methods.

Jan 1, 1939

By Thomas S. Blair

I FEEL a certain sense of responsibility in bringing before you the subject of the direct process in iron manufacture. I am aware that, in such a body as I have now the honor of addressing, there are few who are not already so well informed upon its past history that it would be a weariness to them to listen to anything else than an account of practical success. Yet, to claim that success involves so much that, if I do not make good my claim, I deservedly expose myself to severe criticism. The whole literature of the art, so far as it relates to the direct process, is, up to this time, but a history of failure. It is safe to say that more money, time, and talent have been fruitlessly spent in the pursuit of this object than in all the other unsuccessful efforts in the whole line of iron metallurgy. A distinguished authority in patent law has remarked that " the invention records of the United States and of foreign countries are filled with the waifs and abandoned relics of these abortive struggles." Dr. Percy, whose great work may be taken as an epitome of all that was worth mention, whether useful or curious, in pig-iron metallurgy, up to the date of its publication (1864), after giving elaborate accounts of various attempts at the direct process, condenses his own opinion of all that had been then effected, into a brief but summary comment upon a pamphlet of one of the sanguine inventors who had said: "It is evident that the present mode of working iron

Jan 1, 1874

[United States PAGE Alabama 181 Alaska 181 Arizona 181 Arkansas 182 California 182 Colorado 185 Connecticut 186 Delaware 186 District of Columbia 187 Florida 187 Georgia 187 Idaho 187 Illinois 188 Indiana 189 Iowa 189 Kansas 189]

Jan 1, 1928

By Clarence Zener

[ ] THE present investigation started in an attempt to understand certain details of the decomposition of austenite, and of the effect of alloying elements thereon. As the investigation proceeded it became apparent that not only these details, but all the general features of austenite decomposition, could be understood in terms of fundamental physical principles. Since the direct applicability of these physical principles has not been previously recognized, it was decided to incorporate the original results of the investigation into a review of the general subject of the kinetics of austenite decomposition. This review constitutes the present article. An extended summary of the results is given on pages 27 to 30. This article, which deals with the kinetics of phase transformations, may appropriately be considered as a sequel to two recent articles1,2 from this laboratory on the equilibrium relations in medium alloy steels.

Jan 1, 1946

Jan 1, 1889

By C. P. Proctor, J. T. Crawford

TROUGH washers were among the earliest methods used for concentrating ores; they are referred to by Agricola about the middle of the sixteenth century as already being used while the hand- operated jigging sieve had only recently come into use. For cleaning coal the trough washer apparently was first used in France and Belgium about 1841. The early trough washers were intermittent and the refuse at least was shoveled out by hand. The invention of a continuous jig washer, by a Frenchman, Berard, in 1848, acted as a stimulus to coal washings in jigs and retarded progress in trough washing in the nineteenth century. Chapman and Mott' describe a number of trough washers developed in England and on the Continent from 1850 to 1900, such as the Bell and Ramsay, Ramsay, Bell and Green, Wunderlich, Scaife, McLellan, Lodge, Elliott, Blackett, and Murton. The later of these removed the refuse mechanically, either intermittently or continuously, but in ways that interfered with stratification.

Jan 1, 1943

Page Foreword—H. Foster Bain........................ 9 Letter of Transmittal—F. Julius Fohs...................11

Jan 1, 1927

In a straight caving system, the ore is first undercut and then broken down by its own weight or .by the weight of the overlying rock, or by a combination of both. Operations that involve the caving of the material overlying an orebody as an essential part of the work are also classed as caving, though practically all the ore is broken by drilling and blasting. Actually there are two distinct methods—sublevel caving and block caving, and modifications thereof. The mines described are Miami and Alaska Juneau.

Jan 1, 1925

By W. A. Wood, W. H. Reimann, Maria Ronay

The basic mechanism of fatigue is studied in annealed a brass subjectecl to alternating torsion at room temperature, 100°, 200°, 300°, and 400°C, and in air. It is shown that the slip-zone micro-cracking which characterizes fatigue damage produced by small amplitudes at room temperature is progressively replaced by grain boundary cracking at elevated temperatures, replacement being complete at 400°C. Replacement occurs not because slip activity decreases hut because slip movements at elevated temperatures cease to concentrate in narrow zones and instead disperse. Decrease of amplitude at 400°C through permitting longer lives of specimens before fracture actually causes in- MOST studies of fatigue at elevated temperature have been concerned with data for design. Observations on the basic mechanism of fatigue have been largely incidental, though they have led to the interesting inference that this mechanism has features in common with that of creep.' This paper is concerned primarily with the mechanism itself. Advantage has been taken of mater- crease in pain boundary damage, an anomaly attributed to the greater difficulty at elevated tempwature of starting and propagating a crack. Surface corrosion was most pronounced along slip bands but since at elevated temperatures the slip hands showed no cracking the surface corrosion did not appear to influence onset and early spread of fatigue damage. Similarly the type of fatigue damage produced at room temperature by cyclic strain at large amplitudes, characterized by irregular mi-crocracks at zones between disoriented regions in a grain, was also replaced by mainly grain boundary cracking at elevated temperature, though not so completely. ials and procedures known to show readily how fatigue affects the microstructure of a metal at room temperature, so that direct comparison might be made with what the same procedures show when the material is subjected to fatigue deformation at higher temperatures. 1) MATERIAL This was 70/30 a brass, used extensively in previous studies at room temperature.' Specimens were turned from extruded rod to have parallel test portions 1-1/4 in. long and 7/32 in. diameter, annealed to a grain size -1/10 mm, and electro-

Jan 1, 1965

Jan 2, 1953

By C. E. MacQuigg

In this paper it is impossible to more than touch on many of the commercial alloys of iron, chromium, and carbon, therefore the discussion is confined to the properties of some of the less well-known alloys with upwards of 20-per cent. chromium. The discussion has been based largely on the strictly engineering aspects of the alloys. Chromium has well-defined effects when added to the iron-carbon system. These effects depend on the amount of chromium added and on the composition of the iron-carbon alloy to which the addition is made, i.e. whether low- or high-carbon steel, cast iron, etc. In the case of the low-carbon steels, the chromium addition, when not in excess of several per cent., appears to exert an influence on the properties by its influence on the critical range. In the higher chromium alloys, the physical properties are influenced chiefly by the formation of new complexes, such as iron-chromium solid solutions and, with higher carbon contents, iron-chromium carbides of great hardness. Examination of the published data1 on the critical range phenomena of chromium-bearing steels up to several per cent. chromium indicates an agreement on the following points:

Jan 1, 1923

By Frank G. Miller

The lower cost of producing oil from naturally flowing wells compared with pro-luction costs accruing from artificial lifting methods has stimulated much research, rith the joint purpose of extending the natural flowing life of wells and of increas-ng the productivity of small wells. The iboratory investigation described herein was made to determine the effect of a lotted liner on the pressure gradient in the icinity of the wall of a flowing well. Flow estrictions caused by the liner induce nergy losses between the oil-bearing for-lation and the inside of the liner, which lay be reduced by improved liner design, nd thereby the flow capacity of wells may e increased. These losses have been evalu-ted for rectangular slots of different sizes, nd means are suggested for reducing them. The dearth of information concerning the ature of the flow of fluids from uncon-slidated sands through small openings in he walls of. pipes—as represented by the ow of oil from an oil sand into a slotted ner—is acknowledged. Although the bene-ts to be realized by operators through the se of optimum liners is just beginning to e recognized generally, Coberlyl in 1937 ointed out that the functioning of screen is is an important factor in the pro-uction of oil. From his study on the :lection of size of oil strings for wells in California, Parks2 concluded, in part, that the perforated section of the oil string deserves continued study, especially with respect to the selection of perforations. The growing use of gravel packing resulting from certain research findings lends even more significance to the problem of selecting optimum liners, as the application of these methods usually requires slotted liners or other kinds of perforated liners. The present study was made to obtain further information for the guidance of engineers and operators in selecting slotted liners and to develop a laboratory method that may be used in analyzing possible pressure conditions surrounding most types of perforated casings used in producing oil wells, so that the present inadequate fund of knowledge on this important subject may be expanded. Discussion of ProbleM At the beginning of the investigation the following assumptions were made regarding bottom-hole conditions of a producing oil well and the oil-sand reservoir it penetrates: (I) Conditions of steady-state flow exist, (') a a homogeneous liquid is being produced) (3) no contaminating material (such as drilling fluid) is present between the liner and the face of the oil-bearing sand, (4) the well is vertical and completely penetrates a horizontal sand stratum of uniform thickness occurring between two impermeable strata, and (5) the flow is wholly viscous. If the foregoing assumptions are made, with the added requirements that the sand

Jan 1, 1941

By Walter Knox, Charles H. Sawyer

All of the coals commonly used in domestic bituminous stokers form coke, and satisfactory operation depends upon the fact that the coke formed is so weakly bound together that it breaks readily in the normal operation of the stoker and automatically maintains a good fuel bed. Some coals, because of their tendency to form solid, blocky coke, are practically excluded from use in small domestic stokers as now built. Other coals, some among the best stoker coals available, can form this troublesome coke under certain conditions. Many contradictory methods have been offered as cures for coke formation. Generally the procedure has been to try various adjustments until a combination was found that seemed to give better results. Such random methods of treatment have not provided any reliable information as to causes. The present paper covers a comprehensive test program undertaken by the Koppers Company's Stoker Coal Research Laboratory at Kearny, N. J. The program had two main objectives; first, to discover what factors affected coke formation, and second; to define corrective steps that could be applied in stoker service work. Conclusions and Results i. The design of the stoker outweighs in importance all other factors capable of improving coke formation. 2. Insufficient air supply aggravates the formation of large blocky coke, although raising the air above 30 to 40 per cent excess (as determined during steady running) does not further improve the character of the coke formed and only reduces its accumulation at the expense of efficiency, increased fly ash, poorer clinker-ing, and other disadvantages. 3. Increasing the coal feed results in a somewhat more friable coke structure and is recommended for persistently troublesome jobs. 4. Increasing over-fire draft improves the character of the coke formed and reduces troublesome accumulations by accelerating off-period burning, although at some expense in efficiency and some increase in fly-ash accumulation. 5. Coke structure was not substantially improved by blocking some of 'the retort tuyeres, although the blocking of tuyeres at the feed-screw end of a rectangular retort did lead to somewhat improved performance, possibly because of considerably better distribution of coke in the fuel bed. 6. With the equipment tested no difference was shown between installation of the same stoker in a steam boiler and a warm-air furnace, or between a sand-filled and a ventilated type of hearth. 7. The following design features had no noticeable effect on coke formation: a. Presence or absence of coal-tube air as provided by many manufacturers to eliminate smoke-back. B. Presence or absence of a flap damper ill the air duct to minimize off-period burning. c. Continuous or intermittent (ratchet and pawl driven) movement of fuel feed screw.

Jan 1, 1944

By Glenn C. Waterman, Scott Hazen

3.1-1. Purpose. Development drilling is directed towards determining the grade, volume, and three-dimensional outline of a mineralized zone previously located by exploration. It is distinguished from exploration or reconnaissance drilling, which has as an objective the discovery of new mineralized areas. A development drilling and bulk sampling program should furnish the following information: 1. Geology of the mineralized zone. 2. Quantitative data on grade and tons of material within pertinent cutoff limits. 3. Physical size and shape of the deposit. Areas underlain by waste as well as ore. 4. Mineralogica1 and metallurgical characteristics of the ore. 5. I1hysical characteristics of the ore. 6. Hulk samples for metallurgical testing and grade check. 7. Data on other factors that could affect mining operations, such as ground water, ground conditions, etc. 3.1-2. Procedures. There are numerous methods and techniques that are used to acquire pertinent data on a potential ore deposit. The total cost and accuracy of a development program depends on significant evaluation of the geology, proper selection of a drilling method, thorough analysis of sample data, and accurate evaluation of all the information. Knowledge of the geology of the mineral deposit is important in planning the development testing program and in evaluating the data obtained from such a program. Exploration work usually provides some significant information on the general size, shape, thickness, grade, and geology of the deposit. In some cases no further data are needed; in many cases geological complexities suggested by the preliminary work require further geological study. Of considerable importance may be the following:

Jan 1, 1968