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By W. W. Beddow

TWENTY years or so ago I wrote an article on management which consisted mostly of a chart similar to thousands of others of that day showing line functions, staff functions, and the chain of command in a typical mining organization. Since hen we have been "bossing" from the faces to the swivel chair and we have made many errors of no little expense to our companies. We have kept the chart in mind but many times we have changed the functions to fit the people we have had to work with. Good management after all is getting results with the people, the equipment, the supplies, and the natural conditions of the coal seam or seams and adjacent strata present. We have made, with little effort, a good showing with average people and equipment in good natural conditions. We have made a miserable showing (although expending every personal effort) with better than aver- age people and equipment in bad natural conditions. In the latter case many of our stockholders felt that better management would have found some way to save their investment. Perhaps they were right.

Jan 1, 1944

By John S. Johnson

THE purpose of this article is to describe several types of borehole lining in common use, and especially to offer a relatively new means of reducing the expense of maintaining boreholes where they are subjected to corrosive action of water flowing either inside or outside of their casing. In the Anthracite region of Pennsylvania, boreholes are used for many purposes, the principal ones being: openings between the surface and underground workings through which are passed steam, water and compressed-air lines, ropeways from surface hoists to underground rope haulages, conduits for electric power and signal lines, water-discharge lines from underground pumping stations, and inlets to mine workings for flushing material. LININGS FOR BOREHOLES The inadequacy of steel pipe for use in boreholes has long been recognized. Various substitute materials have been tried, including screw-joint cast-iron pipe (Fig. I). Cast-iron pipe, while very effective as a discharge line for acid water (mine water) being pumped to the surface, is not so effective when serving as a conduit for silt and crushed rock being flushed underground for filling mine voids. Terra cotta pipe (Fig. 2) has been used in boreholes, and lasts a long time if the glazed inner surface of the pipe remains intact. Its installation in a borehole is very difficult and is recommended only where it is certain that there will be no subsidence of the surrounding territory. Accessibility in order properly to join each section of the pipe is essential to a satisfactory job. In large water holes, where it is possible to lower a man into the hole for sealing the joints of the pipe, glazed terra cotta pipe has been used successfully for delivering mine water from pumps in the mines. For large holes used for flushing refuse into mine workings where the surface wash is shallow, standard paving brick have been used to form a tube through the wash to the bedrock. These brick are laid radially, backed by common brick and cobbles laid in cement. It is obvious that the shaft through the wash must be large enough to permit a man to work in it. The flushing material is carried through bare rock from the juncture at bedrock to the openings underground. This plan has been used, particularly where a cast-iron surface line is laid upon the surface to carry the flushing material from the breaker to the hole, and down the hole continuously, with no opening to the air at the top of the hole, thereby eliminating the necessity of an attendant at this point (Fig. 3). Another similar type of borehole lining is constructed of hexagonal pieces of vitrified brick (Fig. 4). This type requires a steel drive pipe through the surface wash large enough to provide a finished tube of the desired size surrounded by a brick wall about 4 in. thick. The special bricks are laid in cement, six to a circle, around a lubricated pipe used as a form, and lowered in sections inside the large drive pipe; the bottom section is seated in a socket drilled in the solid rock, having the same inside

Jan 1, 1941

By Attilio Ligasacchi

The production of magnetite in copper smelting has been the subject of wide investigation in the past.1-9 It is accepted that most of the magnetite is produced in the converters and returned to the re-verberatory furnace with the converter slag. Part of this magnetite is circulated back to the converters in the matte. As a result, if proper fluxing practice is not followed, and temperatures in the converting process are not strictly controlled, an undesirable circulating load of magnetite may occur. This might ultimately lead to saturation in the reverberatory bath with consequent settling of the magnetite at the furnace bottom. This paper contains the cumulative results of a series of investigations on the formation and control of magnetite presently being conducted by the metallurgical department of the Chino Mines Division of Kennecott Copper Corp. THE METHOD USED FOR THE DETERMINATION OF MAGNETITE AND OTHER MAGNETIC MATERIALS Conventional wet chemical magnetite analyses are neither reproducible nor theoretically sound. These analyses are sensitive to time, temperature, and heating rate-all factors which tend to decrease their accuracy and reproducibility. To overcome the unreliability of the above method, H. W. Mossman1 developed an inductance bridge magnetite "meter" which completely replaces the wet chemical analysis with the advantage of quicker and reproducible results. Fig. 1 is a schematic diagram of the meter in use in the Chino metallurgical laboratory. When a pulverized specimen with magnetic properties is placed in coil A of the inductance bridge circuit, the permeability of the core is increased, causing a voltage drop across the coil. The unbalance is amplified to operate the balancing motor which adjusts the movable iron core in coils C and D to bring the bridge back to balance. An indicator arm connected to the movable iron core indicates directly the percent, or weight, of the magnetic material in the specimen. Coil B acts as a reference coil and a zero adjustment. The meter is standardized with a set of various amounts of -100 mesh pure magnetite crystals (99.8 pet Fe3O4) thoroughly mixed in a test tube with -100 mesh quartz sand. These mixtures are combined with inert transoptic powder and heated to 140° to 160°C (melting point of the powder) and subsequently cooled to room temperature, solidifying the whole mixture, in this manner eliminating any possible preferential orientation of the magnetite grains. In order to determine the effect of the particle size" of the magnetite and other magnetic materials on the meter determinations, five size fractions were obtained by wet screening of the 99.8 pet pure magnetite and several reverberatory matte and slag samples. The following size fractions were investigated: -80 + 100; -100 + 150; -150 + 180; -200 + 250; -250 + 300 and -100 mesh. The deviation of the meter readings for the various sizes of each sample never exceeded ±0.3 pet. This deviation is considered well within the accuracy needed for common smelter operation procedures. Further investigation proved also that grinding slag and matte samples in our laboratory disc grinder normally produced a powder constituted of 95 pet -200 + 300 mesh. For practical purposes a - 100 mesh size was used as standard for our studies. It was also found that for rapid determinations tamping of the sample in the test tube was sufficient and gave comparable results with those samples solidified with transoptic powder. For the purpose of this study we define the magnetite content in copper smelter slags and matte as the equilibrium amount of crystalline Fe3O4 existent in the specimen at a given reference temperature, excluding any secondary magnetite precipitated in the specimen during nonequilibrium conditions. MAGNETITE DETERMINATION IN SLAGS Since it is impossible to ascertain the status of equilibrium of a conventional slag sample, due to

Jan 1, 1965

By George Weaton

Two years ago the general features of the St. Joseph Lead Company's zinc-smelting process were described.1 At that time the discussion was limited to a description of the production of high-purity electrothermic zinc oxide. The present paper will describe the commercial production of electrothermic zinc metal. Since a fairly complete description of the plant of the Josephtown smelter was given in the earlier paper, the brief recapitulation given here will be limited to mention of additional equip-ment recently installed and a bare outline of the preparatory process. The raw material is zinc sulphide concentrate received from the com-pany's mines in St. Lawrence County, New York. An average dry-weight analysis of this material is: Zn, 58.28 per cent; Pb, 0.56; insoluble, 1.6; Si02, 1.12; Fe, 6.4; CaO, 0.47; MgO, 0.27; S, 31.9; Cd, 0.1; Cu, 0.06; Mn, 0.24. Moisture content is usually about 3 per cent. Three 21-ft. 6-in. diameter, 12-hearth Nichols-Herreshoff furnaces roast the concen-trate to a calcine of average composition (first 10 months of 1938) : Zn, 67.69 per cent; Pb, 0.06; insoluble, 1.75; Si02, 1.26; Fe, 7.24; CaO, 0.47; MgO, 0.36; S, 1.88; Cd, 0.1; Cu, 0.07; Mn, 0.27. The sulphur dioxide gas, after passing through a waste-heat boiler, proceeds through a recently redesigned low-resistance gas-purification assembly to the contact sul-phuric acid plant, of which the capacity is 200 tons of concentrates per day. The calcine is mixed with a portion of returned furnace residues and sintered on 42-in. by 44-ft. Dwight-Lloyd sintering machines, gas-fired. Wind-box gases pass through air coolers before filtering in a 1440-bag Dracco unit, and thence to stack. The Dracco fume is mixed with Cottrell dust, from roaster gas cleaning, and sent to the leach plant, where it is roasted (SO2 to acid plant) and leached with sulphuric acid to recover, as end products, lead sulphate, zinc sulphate and cadmium.

Jan 1, 1939

By Thomas F. Donnelly

Discussion of the paper of THOMAS F. DONNELLY, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 104, August, 1915, pp. 1759 to 1768. F. LYNWOOD GARRISON, Philadelphia, Pa. (communication to the Secretary *).-The paper is of value in giving the public some first-hand information regarding a copper property that from various causes has attracted considerable attention, especially in Philadelphia, and which has also been the source of several fantastic flotations that had little to recommend them. Since 1906, no work has been done on this property under my direction, with the exception of a topographic survey made last winter by Mr. Donnelly, which was intended as the first step in a sound and logical system of development. From 1906 to 1915, desultory attempts were made to develop these orebodies, but as the work was not in competent hands much money was wasted and even more disappeared in ways regarding which it is perhaps not best to inquire. The result is, this interesting property has now practically no more ore developed upon it than in 1906, despite the fact that a new 100-ton mill is being erected, although, as I have intimated, it is today not much more than a prospect. Turning now to the scientific and more agreeable side of the subject, it is interesting to note that these Santo Domingo copper ores are invariably found in volcanic tuffs and that, in a geologic sense, they are all very old, for there are no evidences of recent volcanic activity in the greater Antilles, of which this island is the second largest. The existence of copper in tuffs in different parts of the world is a notable fact. Often, if not usually, it is present in mere traces, but not infrequently we find it in sufficient amount to be of economic importance. Thus, for example, chalcopyrite and bornite occur in the Tertiary tuffs of Japan, and a number of producing copper mines of that country are either actually in, or closely associated with, rocks of this character. Whether the copper minerals are original primary ores in the tuffs, or were derived from accompanying eruptive dikes, appears not yet to have been determined in any instance. In most of the Japanese cases of which I can find any record the tuffs appear to be associated with shales and limestones. These Japanese copper ores also carry some gold, especially in the upper parts of the veins; in this they resemble the Santo Domingo deposits which not infrequently carry as much as $6 or $7 per ton of gold on the outcrop. As a rule the content of gold in both the Japanese and

Jan 12, 1915

By Colin J. Dixon

The full realization of the potential of computers in geological in- formation system demands new approaches to the machine representation of information. At the same time, the feasibility of such a system, particularly in commercial field, demands greater freedom in input preparation and a degree of standardization in the arrangement of subject matter system. The paper describes some of the basic notions of project "GEOSEMANTICA 70". The aim of the project is to devise means of storing real geological informations in a machine rather than the representation of the information in human language form. This is seen as the only long-term solution to the problems of the complex vocabulary of geology and the complex syntax of geological description. Effectively, a machine language is being defined, consisting of a set of symbols and a date structure for representation of geological and related information. Beyond this, is the definition of a set of rules allowing the use of constrained text as an input/output medium. The investigation is oriented primarily to the representation and handling of information about mineral deposits and the associated geographic, economic and engineering information.

Jan 1, 1969

By Galen Clevenger

THE losses of gold and silver occurring during the conversion of the precipitate, resulting from the cyanide process, into bullion may occur in two ways: first, there may be mechanical losses during the handling of the precipitate up to the time that it is charged into the melting furnace; and second, there may be losses after the precipitate reaches the melting furnace. Much of the loss during the handling of the pre-cipitate can be eliminated, and in fact, in modern plants this loss is known to be very small; particularly since preliminary acid treatment of the precipitate with the attendant extra operations has been abandoned in all but certain plants where gold predominates and this extra step is still deemed necessary. The losses in the melting furnace are from dusting and volatilization; losses in the furnace bottom and linings; floor sweepings; and slag and matte. The gold and silver in the: products which do not: go out of the flue are readily recoverable by standard methods, and while there may be considerable gold and silver tied up at times, the ultimate loss with careful "work should be small. The losses resulting from volatilization and dusting in connection with the melting of the silver slime from copper refineries have been determined by standard methods, and the possible recovery: definitely estab-lished through the installation and operation of electro-static precipitation units. This subject has not been thoroughly investigated in connection with the melting of`. cyanide precipitate; at least, there are no published accounts of such tests. Experiments have been made in the past to determine melting losses by weighing and assaying the precipitate, but this method gives results which are uncertain on account of the difficulty of accurately sampling and assaying cyanide precipitate. Attempts to ascertain these losses by bubbling a measured sample of the gas through cyanide solution or, other absorbent have likewise failed to give depend-able results.

Jan 1, 1922

By Alfred F. Brainerd

Some fifty years ago, iron-ore was discovered near the town of Sheldon, Franklin County, Vermont, in a vein out-cropping on a knoll near Black Creek, which empties into the Missisquoi River a couple of miles away. A short time after this discovery, the owners, Mr. TV. 0. Gadcomb and Hon. Lawrence Brainerd, both of St. Albans, commenced mining (mostly by open cut), and also erected a Catalan forge, from which iron blooms were produced, most of which were worked into bar-iron and used in the neighborhood of the forge, while some were shipped by Lake Champlain to Troy, Albany and New York. But by reason of the lack of any railroad connections, and an insufficient demand for the blooms, this forge was subsequently abandoned, and the material used in its construction removed to other places. Mr. Keith, of Sheldon, used for many years a mixture of this ore with bog-ore from Swanton, in a charcoal blast-furnace, the product of which he consumed partly in his own foundry, shipping, however, a considerable amount to Troy and New York. Accurate data as to this enterprise are not at hand. The same vein has since been traced for some 20 miles, and some prospecting has been done 011 its outcrops at Berkshire, Enosburg and a few miles east of St. Albans; but the vein being small, only a few car-loads of ore were taken out from these places. The commencement of the St. Albans Iron and Steel Works in 1872, and the erection in 1877 of a ten-ton Siemens open-hearth furnace for the manufacture of steel rails, opened a new use for this ore. The furnace-charge consisted of pig-iron, old mils, steel scrap, and magnetic iron ore, added towards the close of the heat. The ore

Jan 1, 1885

By F. L. Wolf

THE tests here described were made to obtain information regarding costs, efficiency, etc. of baking cores in an oil-fired oven, and two electric ovens, which were installed, early in 1920, in the core room of The Ohio Brass Co. and were used almost continuously during the rest of that year. Operating costs were rather high so a complete test was undertaken early in 1921. The ovens will be referred to as Nos. 1, 2, and 3. Nos. 1 and 2 are electric ovens of different makes while No. 3 is an oil-fired oven made by the firm that made No. 2. The three are equipped with similar ventilating devices. They have full-height doors at front and rear. The cores are placed on iron racks, which are lifted by Cowan trucks and rolled into the ovens through the front doors. When baked, they are removed through the rear doors. Fig. 1 shows the general plan of the electric ovens while Fig. 2 shows the plan of the oil-fired oven. Oven No. 1 is 91 in. (231 cm.) wide, 83 in. (210 cm.) high, and 79 in. (200 cm.) deep, inside measurements. The walls are constructed in, panels about 18 in. (46 cm.) wide and 4 3/16 in. (10.6 cm.) thick, packed with blocks of insulating material and covered with sheet iron. The concrete floor on which the ovens set is 13 in. (33 cm:) thick. A recess about 5 in. (13 cm.) deep was cut in the floor to provide room for the heating units. Channels and plates supported. on I beams serve as' supports for the trucks and racks. The ventilating system consists of a Sirroco No. 1 ½ fan, connected so as to draw air from the top of the-oven or from the room, through damper C, and to deliver it either to the bottom of the oven or to the floor; the delivery is controlled by the vane A. The fan and pipes are covered with ¼ n. (6.3 mm.) asbestos cement lagging.

Jan 4, 1922

By Carleton C. Long, George F. Weaton

Two years ago the general features of the St. Joseph Lead Company's zine-smelting process were described.' At that time the discussion was limited to a description of the production of high-purity electrothermic zinc oxide. The present paper will describe the commercial production of electrothermic zinc metal. Since a fairly complete description of the plant of the Josephtowlz smelter was given in the earlier paper, the brief recapitulation given here will be limited to mention of additional equip-ment recently installed and a bare outline of the preparatory process. The raw material is zinc sulphide concentrate received from the company's mines in St. Lawrence County, New York. An average dry-weight analysis of this material is: Zn, 58.28 per cent; Pb, 0.56; insoluble, 1.6; SiO², 1.12; Fe, 6.4; CaO, 0.47; MgO, 0.27; S, 31.9; Cd, 0.1; Cu, 0.06; Mn, 0.24. Moisture content is usually about 3 per cent. Three 21-ft. 6-in. diameter, 12-hearth Nichols-Herreshoff furnaces roast the coacentrate to a calcine of average conlposition (first 10 months of 1938): Zn, 67.69 per cent; Pb, 0.06; insoluble, 1.75; SiO², 1.26; Fe, 7.24; CaO, 0.47; MgO, 0.36; S, 1.88; Cd, 0.1; Cu, 0.07'; Mn, 0.27. The sulphur dioxide gas, after passing through a waste-heat boiler, proceeds through a recently redesigned low-resistance gas-purification assembly to the contact sulphuric acid plant, of which the capacity is 200 tons of concentrates per day. The calcine is mixed with a portion of returned furnace residues and sintered on 42-in, by 44-ft. Dwight-Lloyd sintering machines, gas-fired. Wind-box gases pass through air coolers before filtering in a 1440-bag Dracco unit, and thence to stack. The Dracco fume is mixed with Cottrell dust, from roaster gas cleaning, and sent to the leach plant, where it is roasted (SO² to acid plant) and leached with sulphuric acid to recover, as end products, lead sulphate, zinc sulphate and cadmium.

Jan 1, 1943

By George F. Weaton, Carleton C. Long

Two years ago the general features of the St. Joseph Lead Company's zine-smelting process were described.' At that time the discussion was limited to a description of the production of high-purity electrothermic zinc oxide. The present paper will describe the commercial production of electrothermic zinc metal. Since a fairly complete description of the plant of the Josephtowlz smelter was given in the earlier paper, the brief recapitulation given here will be limited to mention of additional equip-ment recently installed and a bare outline of the preparatory process. The raw material is zinc sulphide concentrate received from the company's mines in St. Lawrence County, New York. An average dry-weight analysis of this material is: Zn, 58.28 per cent; Pb, 0.56; insoluble, 1.6; SiO², 1.12; Fe, 6.4; CaO, 0.47; MgO, 0.27; S, 31.9; Cd, 0.1; Cu, 0.06; Mn, 0.24. Moisture content is usually about 3 per cent. Three 21-ft. 6-in. diameter, 12-hearth Nichols-Herreshoff furnaces roast the coacentrate to a calcine of average conlposition (first 10 months of 1938): Zn, 67.69 per cent; Pb, 0.06; insoluble, 1.75; SiO², 1.26; Fe, 7.24; CaO, 0.47; MgO, 0.36; S, 1.88; Cd, 0.1; Cu, 0.07'; Mn, 0.27. The sulphur dioxide gas, after passing through a waste-heat boiler, proceeds through a recently redesigned low-resistance gas-purification assembly to the contact sulphuric acid plant, of which the capacity is 200 tons of concentrates per day. The calcine is mixed with a portion of returned furnace residues and sintered on 42-in, by 44-ft. Dwight-Lloyd sintering machines, gas-fired. Wind-box gases pass through air coolers before filtering in a 1440-bag Dracco unit, and thence to stack. The Dracco fume is mixed with Cottrell dust, from roaster gas cleaning, and sent to the leach plant, where it is roasted (SO² to acid plant) and leached with sulphuric acid to recover, as end products, lead sulphate, zinc sulphate and cadmium.

Jan 1, 1943

By Irving H. Wentworth

The little town of San Nicolás, Tamaulipas, Mexico, lies approximately 60 miles east of Linares, situated in the State of Nuevo Leon, and 150 miles SE. of Monterey, as shown in the sketch-map, Fig. 1. The place is reached from Monterey by the Tampico train as far as Linares, a distance of 92 miles, and then by coach the rest of the way. It is situated in a narrow valley between low hills, the houses forming one main street and a plaza. It is peopled by about 500 inhabitants. The climate is temperate, the thermometer ranging from 90" in summer to a few degrees below freezing-point in winter; but this severe weather only lasts a day or two at a time, when the " northers " blow. There are no streams in the vicinity, but water sufficient for the use of the people is obtained from wells. The rainfall is about the same as that in the rest of NE. Mexico. The rainy months are July, August, and September. The rest of the year is practically dry, with an occasional showery day or two during the winter, when a " norther " is blowing. Timber is abundant in many localities. There are two varieties of oak, besides mesquite, ebony, "maguira," "patol," and a number of other kinds of trees indigenous to this region. I. History. On the discovery of the silver-lead bearing veins occurring in this district, the mining-camp of San Nicolás was founded in 1767 by the Spaniards, and numerous mines were opened and worked for a distance of about 3 miles east and 5 miles west of the town. At the western extremity and near the Car-rolefia mine, a small town called San Pedro was huilt. The

Jan 1, 1913

By Samuel Hoyt

THE writer has long been interested in seeking an explanation of the upper heat effect in the copper-tin alloys over the a + ß range, first described in 1913. These notes are offered, not at all as the final explanation of this heat effect, but rather to indicate certain progress which has been made toward establishing what happens over this temperature interval. While working on the thermal analysis of the copper-rich kalchoids (copper-tin-zinc alloys), it was noted that those alloys containing major portions of tin and minor portions of zinc exhibited two marked heat effects, one at about 520° C. and the other at about 600° C., instead of the single effect which is generally observed in either of the two binary series. This matter was discussed with Dr. Guertler, who suggested that a heat effect at about 600° C. in the pure copper-tin alloys might be expected. This led to a more searching examination of the thermal critical points in the pure copper-tin alloys, with the result that a marked, although somewhat weak, heat effect was located at about 600°. Somewhat later, this upper heat effect was discussed with Dr. Burgess, and it was requested that the Bureau of Standards make heating and cooling curves of one of these alloys for the purpose of removing any possible doubt as to the actual presence of the heat effect. Results obtained by the Bureau are given in Plate I. In an earlier paper1 differential curves were published showing that the heat effect occurred at constant temperature over the a + ß range and increased in magnitude with the amount of a up to a point somewhat above 20 per cent. tin. No heat effect was noticed at this temperature in the eutectoid alloy. The existence of this heat effect seems to require a modification of the present copper-tin diagram in the a + ß field, and it has been the object of the work here presented to secure the evidence upon which such a change should be based.

Jan 12, 1918

By J. H. Swisher

An experimental study has been made of the possible mechanisms for foam stability in the system CaO-SiO2-Cr2O3, where Cr2O3is the foaming agent. The degree of lowering of surface tension by Cr2O3 was determined at 1600 "C for high -silica melts. Measurements were also made of foam stability under standardized conditions. The results of the two sets of measurements then were correlated by applying the Gibbs and Marangoni theories of film elasticity. It was demonstrated that the Marangoni elasticity effect is probably the largest single contributor to foam stability, although the high uiscosity of' silicate melts makes some contribution in controlling the rate of drainage of liquid from bubble lamellae. ThE tendency of metallurgical slags to foam has frequently been observed during steel-refining operations. In the open-hearth furnace,this tendency is considered undesirable because it slows down the rate of heat transfer from the burners to the molten-metal bath. On the other hand, it is sometimes desirable to have a "foamy" slag in the basic oxygen converter.' A more effective blanket over the steel bath is made by a "foamy" slag, and loss in yield of metal due to splashing is minimized. In addition, a flush slag can be removed more easily in this condition. Since slag-foaming problems in the field have been attacked largely on an empirical basis, it appeared desirable to obtain a better basic understanding of the mechanism of foam stability. The experimental work was directed almost entirely toward the behavior of Cr2O3 as the foaming agent in CaO-SiO,-Cr2O3 melts. In the first stage of the investigation, the degree of lowering of surface tension by Cr2O3 was determined at 1600°C. The second stage consisted of measuring foam stabilities under standardized conditions. The two sets of experimental results then were correlated by applying various theories of foam stability. For convenience in interpreting the surface-tension and foam-stability results reported here, a portion of the CaO-SiO2-Cr2O3 phase diagram2 is reproduced in Fig. 1. EXPERIMENTAL 1) Surface-Tension Measurements. Very little information is available in the literature on the lowering of surface tension of slags by foaming agents. Kozakevitch 3 mentioned that the addition of 1.5 pct Cr2O3 lowered the surface tension of FeO slightly. In another system, some data on the lowering of surface tension of foaming slags by P2O5 were reported by Cooper and Kitchener.4 The technique used for the surface-tension measurements was the maximum bubble-pressure method,' using a single tube immersed to various depths in the melt. This method has been used extensively in high-temperature systems, such as in liquid metals, slags, and glasses.6,7 It has the advantage that the contact angle between the liquid and the tube material need not be known. The equation used for calculating surface-tension values from maximum bubble-pressure measurements is the Schroedinger equatioq5 which can be written as follows:

Jan 1, 1964

By Keats, J. L.

IN THE literature on the elimination of metalloids in basic open-hearth practice, there are a great many heats recorded in which excellent data on changes in slag and metal composition during refining are given, but in almost all of these heats either temperature data or weights and analysis of charge are unrecorded and observations on the physical charac- teristics of the slag are almost always lacking. With these points in mind, a test heat was made in which as complete as data possible on all the factors that affect the elimination of metalloids were obtained.

Jan 1, 1957

By Jay N. Fairbanks, Richard G. Robinson

This paper discusses a computer program and related formulas for fire fighting responses by coal mine personnel. The computer will interpret the mine air analysis, print reports, and provide relevant graphs allowing quick and accurate responses to coal mine fires.

Jan 1, 1983

By Ernest N. Patty

WHEN an Alaskan prospector makes a new mineral discovery he stakes out his claims and then starts prospecting for a near-by landing field. This may be a convenient lake but more often it is a gravel bar along a river, where, by cutting off some brush and throwing the larger rocks to one side and then tying a flour sack to a pole, he may decoy some intrepid aviator into testing it gingerly with the wheels of his plane. It was only a few years ago that .the fence around the baseball park at Fairbanks, Alaska, was taken down so that planes could get in and out of the ball park without ripping off boards. Today the grandstand is lost among the modern hangars which line one side of a modern and busy airport. Planes come and go all during the day, and in summer, when there is no darkness, the night stillness is frequently broken by the hum of a motor overhead. Fairbanks is the hub of interior Alaska and from that hub airplanes radiate in all directions to mining camps large and small. An air industry of comparable size is based at the town of Anchorage, and in fact there are but few towns of more than 200 population in the Territory that do not have one or more planes based there.

Jan 1, 1937

By W. J. Sharwood

(San Francisco Meeting, September. 1915) THE assay or estimation of the total gold content of an ore presents little difficulty, when circumstances permit of securing a thoroughly representative sample. The general practice has been fairly standardized, and such errors as occur in the results obtained are for the most part attributable to the methods of sampling rather than to those of assaying, while duplicate assays made by skilled workers usually agree closely. When it is a question of estimating the "free" or amalgamable gold of an ore, as opposed to the total gold, there is but little uniformity in the methods employed by different workers, and often equally little in the results obtained when duplicate determinations are attempted, no satisfactory standard method having been generally adopted. The methods in use are of two general types-"panning" and "amalgamation."

Jan 8, 1915

By Duncan MacVichie

The iron fields described here are located in the Iron Springs and Pinto mining districts, Iron County, Utah. This region is in southwestern Utah, about 260 miles south from Salt Lake City, and is reached by the Los Angeles & Salt Lake railroad of the Union Pacific system. The iron fields lie at an elevation of 5500 to 7500 ft. above sea level, and are essentially desert in character. They are covered with a light growth of sage brush, piñon pine, and scattered cedar. Weather conditions are unusually favorable for all-year mining operations, the winters being mild with little or no snow; and the summers not excessively hot, the temperature rarely rising to 100 during the day, while the nights are invariably cool. The iron-ore bearing area extends from the Iron Springs district to the Iron Mountain mining district, being approximately 25 miles long in a northeast-southwest direction, and from 1 to 3 miles wide in a northwest-southeast direction. In the Iron Springs and Pinto mining districts, the ore occurs at various points around three sides of Granite Mountain and Iron Mountain. This is readily understood by reference to Figs. 1-4. These mountains are composed of andesite, which has been forced up through the surrounding sedimentary formation, in the form of laccoliths. An extensive report on the geology of these districts was made by Leith and Harder,' who state: The three dominating geological features of the district are three large andesite laccoliths which constitute the Three Peaks, Granite Mountain, and Iron Mountain; lying in a northeast-southwest line across the area in question. Three unconformable sedimentary series, aggregating 4000 ft. in thickness, outcrop in successive rings around these laccoliths, dipping outward asymmetrically, very steeply at the contact, less steeply farther away. Still farther from the laccoliths, lava-flows 2000 ft. thick rest in nearly horizontal attitudes on the tilted sedimentary rocks. These general relations are modified by faulting. All of the rock formations of the district are more or less covered on the middle and lower slopes by unconsolidated and partly consolidated erosion debris, both aqueous and subaerial, which spreads out on the lower ground to make the deserts.

Jan 1, 1927

By Harry H. Power

INDUSTRY has the right to expect the petroleum engineering schools to supply more than the minimum technical qualifications necessary to obtain or discharge the responsibilities of a particular job. The basic training, social and economic orientation, should go far beyond these minimum requirements. Petroleum engineering students should also be well grounded in the history of the oil business so that they may understand the industry's progress since the advent of the Drake well. Furthermore, according to P. H. Bohart, the schools "have a definite duty to help the students form a workable philosophy of life, which includes an appreciation of the service of science to mankind, and a belief in the obligation of the individual who enters a profession to exalt himself by continuing his studies and growth so that he may never cease making contributions to the advancement of science and industry."

Jan 1, 1948