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By D. R. George

Preliminary research has identified several organic and aqueous solutions that are effective absorbents for SO, from simulated smelter gas containing 0.3 to 2% SO2. These SO2 loaded solutions are also compatible to the reaction of H2S and SO2 to precipitate a readily filtered elemental sulfur. The economic removal of SO2 and production of elemental sulfur from stack gases discharged by base- metal smelters is a challenging goal. The magnitude of this task is illustrated by the estimate that about 3.5 million tons of SO2 are discharged to the atmosphere by smelters annually in the U.S. The SO2 concentration of the gases ranges from about 0.5 to more than 3%. As the sulfur content of SO2 is 50% a potential production of 1,750,000 tons of sulfur per year is indicated.

Jan 1, 1970

By J. N. Munro

At the present stage of geothermal technology and the still limited applications of geothermal energy, most of us consider any use of "things geothermal" to be something out of the ordinary. If in such a situation there can be a use of geothermal energy which is even more unusual, then the utilization of geothermal energy-or more precisely, geothermal heat--for the manufacture of salt is just such a use. This is the essence of investigations in the Fiji Islands, where experiments in the evaporation of seawater to product, salt have been conducted using geothermal heat emanating from the ground in an area of hot springs. The hot springs are located on the coast at Savusavu in a depression about GO ft wide. There are ten individual springs, but most of these are small and insignificant. The temperature of the water from these springs reaches 100°C.

Jan 9, 1964

The following list of corrections has been compiled from the thirty-five volumes, with some additions: VOLUME I. Page 160. The first two sentences of the second paragraph should read as follows : " For No. II we find that 2.33 percent. A1,08 take 4.07 per cent. 8109, leaving 3.48 per cent. 8102 free, which requires 3.25 per cent. CaO." Page 160, line 14, 3.79 should be 3.25; and in the 15th and 18th lines, 48.44 should be 46.98. VOLUME VI. Page 59. The discharges of the miners' inch per second, given as .2624 and .2499 cubic feet, should be .02624 and .02499, respectively. The discharges per minute, hour, etc., are correctly given. VOLUME VIII. Page 214. 16th and 25th lines, ferric carbonate should be ferrous carbonate. Page 486, 16th line, 10,000 should be 5,000. [ ]

Jan 1, 1907

By Magnus Troilius

The importance of having methods for the rapid and accurate determination of manganese in modern steel manufacture cannot be overestimated. The method adopted in the laboratory of the Midvale Steel Works is very satisfactory, and I think it will be of interest to some of the members to give a description of it. Before giving the more detailed account of the manipulations, a review of some well-known methods and chemical facts may not be out of place. The " bromine and ammonia" process, as fully described in the tenth volume of the Transactions of this Institute, was certainly an improvement on the methods in which fixed alkaline salts were used, as these gave invariably too high resnlts, as generally carried out. But the separation of all the iron before the manganese was, in both methods, a source of great inconvenience and delay.

Jan 1, 1884

By T. F. Witherbee

(Read at the Amenia Meeting, October, 1877.) THE subject of an article in the Engineering and Mining Journal for October 13th, 1877, namely, Blast Furnace Treatment of Silicious Iron Ores,, is of great interest to myself, and doubtless to many others who have been troubled with a seemingly unaccountable percentage of silicon in their pig iron. It is to be regretted that the author of the article did not give us complete details of his charges, and thus prevent a possibly fatal error in the very beginning of the discussion of the points raised in his communication. As it now stands, I think we will have to fall back upon the statement that, "every conceivable mixture of fluxes and ores (A and B) has been used." Let us first, in order to simplify the calculations, do with the

Jan 1, 1878

By Luis E. Vallejo

Experimental and theoretical analyses are presented to study the mechanics of growth and interaction for three inclined left-stepping, three inclined right-stepping and two inclined non-stepping cracks in a brittle material subjected to uniaxial compression. It was found that the non-stepping cracks did not interact and they propagated individually in a direction parallel to the uniaxial compressive stress. The propagating cracks formed in regions where tensile stresses developed. The left-stepping cracks interacted and formed branching cracks as a result of failure in tension of the material between them. Also, they propagated from their tips in a direction parallel to the uniaxial compressive stress. The right stepping cracks did not interact, but extended themselves from their tips following a direction parallel to the uniaxial compressive stress. The extended cracks formed in areas of compressive stresses.

Jan 1, 1984

G. F. COMSTOCK (author's reply to discussion *).-The discussion of this paper has been of such volume and interest as to constitute in itself a sufficient excuse for the paper, even though the paper itself may have been as much in error as some of its critics have maintained. Mr. Howard does not appear to realize some very practical facts that the opponents of his theory have advanced. Among these are: the coarsely crystalline fracture of the nucleus of a transverse fissure, so different from the smooth fatigue break around it; the occurrence of fissures in large numbers in certain heats or rollings of rails, while other heats or rollings do not develop them; and the much smaller proportion of transverse fissures found in rails rolled .from reheated blooms as compared with direct-rolled rails. These facts are not explained by Mr.

Jan 6, 1919

By Milton Glicken

The airborne geophysicist is a busy man these days. In his plane he may have the airborne magnetometer, the airborne scintillation counter, and the airborne electromagnetic surveying system. Each of these is an independent tool, but all require additional auxiliary equipment for locating the aircraft in space: recording altimeters and Shoran or aerial cameras. Now there is still another piece of equipment, the airborne magnetic gradiometer, an accessory to the magnetometer. To understand its uses, consider the function of the magnetometer itself. Aside from detecting magnetic ore, the airborne magnetometer finds greatest use in spotting intrusions of igneous material. Where there is enough contrast in magnetic susceptibility of igneous rock and adjacent formations, it outlines the intrusion. Certain minerals also influence the magnetometer directly, but with the exception of magnetite and possibly one or two others, their effect is weak and can be detected only when there is sufficient ore and the magnetometer flight passes very close to it.

Nov 1, 1955

By J. D. Cannon

SLAGS studied in this investigation were from 0.25 to 0.35 pct plain carbon steels and were melted in a 3-ton acid-lined Lectromelt furnace with a 2500-kva transformer. The melting process employs a short, violent boil, which is partially blocked, and the desired carbon content is adjusted by pig iron or iron ore, depending on the preliminary carbon. A relatively small volume of slag is used in refinement. Bottom is here defined as that portion of the furnace that comes in contact with the molten metal, or all the surface below the slag line. Bottom trouble-i.e., holes in the bottom lining-is very seldom experienced at our plant. We have been watching the bottom lining over a period of some boo heats in the hope of having holes large enough to supply data for this report, but none occurred during that period. The bottom is eroded uniformly, occasionally with slightly deeper depressions around the taphole.

Jan 1, 1947

By Howard E. Kremers

Since the discovery of the first-known rare earth elements more than a century ago, these metals have always been of academic interest. It is not so well known, however, that a rather stable, respectably large industry based on rare earths and their related materials has been in operation for more than 60 years. Rare earths, of course, are the elements having atomic numbers 57 through 71--lanthanum through lutetium in the periodic table. The most important commercial members of this group are mixtures of the lower atomic-numbered rare earths, and cerium. Although yttrium is not a rare earth, it occurs with rare earths and its properties are so similar to them that. it must be included in a discussion of these elements. In addition, thorium is important to most producers of rare earths because their ores generally contain this element. Thorium extractive metallurgy and technology is closely related to rare earth chemistry due to the frequent similarity of properties.

Jan 4, 1962

By J. A. Benell

DIOXIDE of silicon, commonly called silica, is one of the greatest single constituents of modern in-dustry. It is brought most clearly to the mind when we consider the various kinds of sand and their rela-tion to industry. The major portion of.all sand is silica, and should be its principal component part in building materials. As an abrasive for cutting, polish-ing and sand-blasting, sand serves a vital purpose in many industries. Even lumber is now being sand-blasted, to cut away the softer grains of wood, leaving the harder grains in relief. The result not only in-creases the beauty of the wood, but adds to it an ap-pearance of antiquity. The common uses of silica in industry may be classified about as follows: Chemical industries-filtering medium; manufacture of carborundum; manufacture of water-glass. Paint-inert extender. Mineral fillers-wood filler; filler in rubber, hard rubber, pressed and molded goods, phonograph records.

Jan 5, 1928

By William P. Blake

Travelers in the desert regions of the southwestern portion of United States, especially along the valley of the Colorado of the West, can hardly fail to note that most of the rocky outcrope of the harder rocks have a uniform prevailing blackness of the surface, in strong contrast with the normal color of the interior of the rock when freshly broken. For example, the granitic or gneissic rocks of Pilot Knob, below Yuma, are blackened beyond easy recognition. So also rocks upon the lower Mojave in California are so thoroughly blackened, as if painted, that ordinary gneiss can scarcely be recognized without breaking it so as to show the interior color and structure. The discoloration is not confined to the rocky outcrops in place, but is found upon boulders and upon the loose rounded pebbles which strew the surface of the mesas along the Colorado river. These fragmentary rocks partake of the general blackening.

Jan 1, 1905

By Eugene A. Stephenson

In November, 1932, Dr. Lacey, of the California Institute of Technology, presented before the American Petroleum Institute some of the results of his research under Project 371. The investigations described dealt particularly with changes in the physical properties of petroleum that result from the solution of natural gas therein. The solubility of Santa Fe Springs dry gas, containing 87 per cent methane, 8 per cent ethane and 5 per cent propane, had been determined in various crudes at 100' F., and 2000 lb. pressure per square inch as shown in Table 1 and Fig. 1 herewith. Originally the computations were made in terms of cubic feet per barrel, but' for a more uniform basis of comparison the results are also shown as cubic feet of gas2 per cubic foot of oil.

Jan 1, 1935

By Louis A. Panek

MOST roof bolts are used in mines with bedded roofs, but it has not been determined to what degree thin-bedded roofs can be reinforced by bolting if there is no thick member in which to anchor the bolts, or what function the bolts must perform in such a case. Owing to widespread practice of sys- tematic bolting to support thin-bedded roofs, moreover, it is desirable to design roof-bolting systems on a quantitative basis. Specifically, a solution to the following problem is required: For a roof composed of beds of given thickness and physical properties, what is the optimum length, spacing, orientation, and tightness of bolts consistent with safety and economy? The investigation reviewed here has produced a functional equation to evaluate these variables and establish basic principles of roof bolting.

Jan 1, 1956

The Oregon School of Mines Society held its regular monthly meeting on the evening of October 23. This meeting was an informal reunion at which members gave accounts of personal experiences during the last three months. Many members of both junior and senior classes answered their country's call to arms and so did not return to college. The senior class is particularly well represented in the Army, as two men hold lieutenant's commissions and a third is already in France with a hospital unit. The junior class has also contributed men to various branches of the service. Plans for the regular meetings include discussions by members and lectures by outside authorities oil mining and allied topics. These meetings are open to the lower classes and all others interested. The Oregon School of Mines Society, composed of members of the junior and senior classes, has, joined with the sophomore and freshman relining students in purchasing a Liberty Bond under the name of the Miners' Club of 0. A. C. H. W. THOMS, President.

Jan 12, 1917

By J. Redstone, A. R. Laplante

Sidbec-Normines operates six large iron ore concentrate regrinding mills in parallel and open circuit at its Port-Cartier pelletizing plant. Grinding kinetics in these mills were characterized for slurry densities varying between 70 and 89% solids, using a lumped parameter size discrete model. Optimum grinding conditions were encountered at 83.5 to 84% solids. Higher densities decreased the normalized selection function and increased slurry short-circuiting, yielding a sharply coarser mill discharge. At lower slurry densities, the normalized selection function decreased and the mill discharge coarsened slightly. The grinding kinetic model predicted particle size distributions within the mill. These were found to vary significantly from the feed to the discharge end. This is likely to cause nonlinear breakage kinetics.

Jan 1, 1985

By Calvin C. Brown, John Bigando

Pit slopes at Cananea commonly vary from 50-55°, and some have been standing for over 25 years. Their maximum vertical extent is 700 ft. Investigation of these slopes and the rocks of which they are composed has led to the decision to experiment with final pit slope angles of up to 70". Precision blasting to obtain a smooth final pit wall with minimum raveling is an integral part of this field experiment. Presplitting, one of the precision blasting techniques, requires the drilling of a single row of holes along the limit of a pre- designed excavation. The hole spacings and charge concentrations must be experimentally determined in the field, using published data as a base (Table 1). The holes are fired prior to the main round and carry no burden and therefore produce no broken rock. Thus, it is an operational cost with no direct return on investment.

Jan 9, 1972

By David R. Maneval, Ralph A. Lambert, H. B. Charmbury

Subsidence, although it may or may not be apparent on the surface, is an inevitable consequence of deep coal mining and a frequent cause of damage to surface structures. Efforts to prevent subsidence go back many years, but there is still only one known antidote that is both technically feasible and predictable. This is the hydraulic or pneumatic stowing of solids-or flushing. In coal mines, however, flushing has been rarely used because it is considered the most expensive method of filling such mines, even though the reverse is true for ore mines. It is thus significant that the method has found favor in a comprehensive program the Commonwealth of Pennsylvania has undertaken to eliminate the hazards of abandoned coal mines within its jurisdiction. In "Operation Backfill," as the program is known, the Commonwealth has successfully used hydraulic flushing and fully justified the method economically.

Jan 4, 1967

By D. R. Colton, W. V. Youdelis

The maximum segregation, as a function of alloy composition, is calculated for the aluminum-zinc system using the theory of inverse segregation based on the mechanism of volume contraction and interdendritic flow. The results show good agreement with experiments on aluminum-zinc ingots. The significance of the mass calculations of the segregation theory in discussing the metallography of the cast aluminum-zinc alloys is considered. THE occurrence of inverse segregation in rapidly cooled castings has been reported on previously by various authors, and several theories have been proposed to explain this phenomenon. It is now generally accepted that the mechanism of inverse segregation involves volume contraction on solidification followed by interdendritic flow of enriched residual liquid to the contraction volumes. This increases the concentration of the lower-melting-point constituents in regions of first solidification to above the mean concentration, which is con-

Jan 1, 1961

By R. W. M. Lai

INTRODUCTION Manganese nodules were first discovered by the H.M.S. CHALLENGER expedition of 1873-76 and have engaged the interest of oceanographers and natural resources engineers ever since (1-4). Manganese nodules, some of them as large as grapefruit, cover vast stretches of the ocean floor throughout many parts of the world. In some areas the ocean floor is literally paved with nodules. The Pacific Ocean alone is estimated to contain 1.5 trillion tons of nodules which are forming at the rate of about 10 million tons per year (2). An analysis of the principal metal values for Pacific Ocean nodules is shown in Table I (5). [ ] The principal ingredients of the nodules are manganese and iron, but they also contain other important associated metal values such as copper, nickel, cobalt, and molybdenum. These associated metal values,

Jan 1, 1980