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By Thomas E. Leontis

INTRODUCTION THE importance of magnesium alloys in the manufacture of aircraft engines has been realized for many years. A concentrated effort has been exerted in the laboratories of the Dow Chemical Co. to develop magnesium-base alloys with improved properties at elevated temperatures whereby greater advantage can be taken of the inherent lightness of these materials. In an earlier publication,1 attention was called to the superior tensile properties and resistance to creep of cerium-containing magnesium alloys at temperatures up to 700°F. More recently, additional data on magnesium-cerium alloys have been furnished by Murphy and Payne.2 The present paper deals with the mechanical properties of sand-cast magnesium alloys containing zinc, at temperatures up to 500°F. The study includes binary Mg-Zn† alloys containing up to 10 pct zinc and several ternary and some polynary alloys based on the Mg-1Zn,†Mg-3Zn, Mg-4.4Zn, Mg-6Zn, and Mg-10Zn binaries. The compositional variation in the tensile properties, hardness, and creep at room and elevated temperatures, and in the electrical conductivity at room temperature has been determined. The results of these tests show that many zinc-containing magnesium alloys exhibit resistance to creep at elevated temperatures significantly higher than that of present commercial magnesium alloys, but lower than that of alloys of the magnesium-cerium type. In addition, they have high tensile properties at room and elevated temperatures and high conductivity. This combination of mechanical properties and conductivity indicates that these alloys should be given serious consideration for commercial applications involving exposure to temperatures higher than those to which present commercial magnesium alloys can be taken safely. LITERATURE The properties of sand-cast magnesium alloys containing zinc as a principal alloying element have not been investigated very extensively, especially at elevated temperatures. The following remarks, which are confined to sand-cast alloys, will serve as a summary of the most important references on this phase of magnesium metallurgy. The first recorded determination of the tensile strength of binary Mg-Zn alloys as a function of zinc content was reported by Aitchison.3 Similar studies, including the measurement of elongation and hardness, have been performed by Gann and Winston,4 Dumas and Rockaert,5 Haughton and Prytherch,6 and by Spitaler, the last being reported by Beck.7 A slight superiority in the tensile strength of chillcast Mg + 8 Zn alloy over the sand-cast alloy was noted by Maybrey 8 That alloys of magnesium containing 5 to 12 pct zinc

Jan 1, 1948

PORPHYRY mining in the Bisbee district in Arizona did not begin until 1923, though Bisbee had been the scene of profitable copper-mining operations since 1880, and during the interval had contributed roughly 2,000,000,000 lb. of copper to the world's supply. At that time it ranked third among the copper districts of the United States, first place for total production going to Butte, Montana, and second to the district centering around Calumet, Michigan. Bisbee's production had come from the so-called "limestone" mines operated principally by the Phelps Dodge Corporation and the Calumet & Arizona Mining Co. Each of these companies had a large smelting plant at Douglas, 25 miles southeast of Bisbee on the Mexican border. The town of Douglas owed its existence primarily to the copper mines of Bisbee, the particular location having been determined, first, by the fact that water in adequate supply could be obtained by sinking wells; and, second, by its position about equally distant from Bisbee and the mines in Sonora, Mexico, of the Moctezuma Copper Co., a Phelps Dodge subsidiary. Three partners, Martin, Reilly, and Ballard, conducted the first operations of consequence at Bisbee about 1880; and in 1881 a smelting plant consisting of two 36 in. water-jacketed blast furnaces was erected near by. The ore came from open-cut workings on the later-to-be-famous Queen orebody. The furnace charge is said to have averaged 23 per cent copper-twice as rich as the concentrates from the mills and four times as rich as the smelting ore shipped from Bisbee in recent years. As early as 1881, disputes arose among owners of various claims, and groups of claims, over the ownership of orebodies under the law of apex and extra-lateral rights. This law gives a miner the right to follow his vein downward on its dip, even

Jan 1, 1933

By Richard Rothwell

At the last meeting of the Institute, Mr. Per Larsson read a very interesting paper on the Chapin mine of Michigan, in which he described the systems of mining that had, at different times, been tried in that great ore-body, and especially the system now in use, which consists in working the ore out from the bottom upward in lifts. Shortly after that paper was written, but before it had been published, or that I had had an opportunity of reading it, I bad the pleasure of visiting the mine. At that time I was making a profes sional examination of a nnmber of the mines on theGogebic Range, and others in the Menominee region, Michigan and Wisconsin, and had occasion then, as during several previous visits, to study closely the methods and cost of mining in these districts. As the outcome of these investigations, it appeared evident to me that the system of working on the chamber-and-pillar plan, which up to that time had been the only method of underground work adopted in the Gogebic

Jan 1, 1888

This discussion of the paper of Chester W. Washburne should have been printed following the remarks of H. A. Wheeler, in Bulletin No. 100, April, 1915, pp. 835 and 836, but was inadvertently omitted. ROSWELL H. JOHNSON:-There is one reason why the hydrostatic interpretation of gas pressure is not wholly acceptable. As we go clown in the sands we seem to get excesses of gas. Particularly in this field it becomes excessive in quantity relative to the amount of water in the sand. If this holds in other fields as well it must mean that there has been an ascension of water, because these sedimentaries when laid down, were filled with connate water. If we do get an ascension of connate water, produced by some such phenomena as its expansion by heat or by the formation of new gas by pressure upon organic materials at great depth, we can hardly expect the pressure to be controlled merely hydrostatically. * In reply to Mr. Wheeler's inquiry as to gas wells with pressure higher than hydrostatic pressure, I would cite the original wells given by Orton on which he based the hydrostatic theory. He used in his calculation a head of 600 ft. above tide, assuming the outcrop of the Manitoulin Islands to be in Lake Superior, whereas the Trenton does not outcrop at Lake Superior. The Manitoulin Islands are in Lake Huron, the level of which is 580 ft. above tide. No allowance is made for the lower density of the fresher water near the outcrop, the weight taken for the whole column being the water of high density found at the wells.

Jan 5, 1915

By S. F. Emmons

[The following notes of observations made during a visit of a few days in the month of October, 1886, which was cut short by a sudden summons East, are offered, in spite of their incomplete and tentative character, in the hope that they may aid the members of the Institute, in their coming visit to this region, to a clearer understanding of the general geological conditions under which the ore-bodies occur.] The Butte mining region lies in a sort of a depression in the mountains which is drained by Silver Bow creek and its various tributaries. On the east it is bounded by high north and south ridges of granite, and on the west by lower ridges, also running north and south, which, as far as examined, were found to consist of rhyolite. High mountains also inclose the depression on the north and south, but at a greater distance than the more immediate bounding ridges on the east and west, the distance between which is hardly more than six miles.

Jan 1, 1888

By Robert L. Slobod

In much of the work reported in the literature on long cores. true connate water value, probably have not been obtained because of insufficient flow of 011 to attain equilibrium. A -.satisfactory method for establishing connate water in long cores has been developed in which oil flow is maintained until no additiona1 water is displaced. INTRODUCTION Long cores have been used by sev-erals investigators in an effort to evaluate the efficiency of oil recovery for various producing schemes. The effects of many variables such as rate of displacement. pressure drop, volume of displacing medium, gas-oil ratio, inter-facial tension, and others have been investigated, and the merits of gas drive have been compared with water drive. In the older experiments no connate water was used. but in the more recent stndies the philosophy of the experiment calls for a core containing oil and connate water (irreducible water) as the starting point of the experiment. The method generally used to establish this condition in long cores involves dynamic' displacement wherein one or more phases are forced through the core. flow being maintained at a constant rate or at a constant pressure until a steady state is reached wherein there is no change of saturation with time. It is one purpose of this paper to point out that in much of the work reported in the literature true connate water values probably have not been obtained. The reason for this failure is pointed out. and a method for obtaining more reliable connate water values on long cores is presented. It is impossible at this time to completely evaluate the effect on the conclusions in the earlier papers resulting from the failure to obtain true connate water in the long cores, but some data are presented which indicate that serious errors may he present in many cases. MATERIALS AND APPARATUS Cores cut front outcrop sandstones (Strawn. Torpedo, and Elgin sandstones) with permeabilities of the order of 300 md were used. The major experiments were made with a core 18-in. long and 2-in. in diameter. Cores of the same diameter but only 12-in. long were used in a few tests? and in some work a core I-in. in diameter and 11-in. long was used. These materials were all somewhat bentonitic. 'To reduce the effect of such constituents, one of the cores (Torpedo No. 10) on which the most work was performed was acid extracted at the start of the experiment. Brine containing 50,000 ppm chloride and naphtha (Stoddard's Solvent) were used as the water and oil phases, respectively. The core was mounted in a rubber sleeve which forms the inner lining of a brass cylinder. In this arrangement2 the rubber sleeve is forced against the core by applying pressure to water in the annular space between the rubber sleeve and the brass cylinder wall. The core is therefore sealed in rubber so that all fluids introduced at the input end of the core flow through the core. With this equipment the core may be easily removed for inspection and analysis. Also, other cores may be introduced for study with no extra time for preparation such as is required when plastic mounting is used. When pressure or conductivity measurements are desired at intermediate points along tile length of the core, the brass cylinder comprising the outer jacket of the core holder is cut into section, of the desired length. Each section is then made up as an individual unit with its own rubber sleeve (see Fig. 1). The individual units are then butted up against a ring of plastic or other insulating material which carries an electrical contact for resistivity measurements and an opening which can be used for the measurements of fluid pressures. The individual units are forced tightly against the plastic ring separators and held in place with several tie rods. Inlet and outlet end butts of the same diameter as the core and several inches in length are provided to control the introduction and withdrawal of fluids and to complete the arrangement for sealing the core within the rubber sleeve. Fluid flow is maintained either by applying pressure to the liquid confined in a reservoir or by the use of a gear pump. The latter is preferable where continuous flow at a moderate rate over a long time interval is desired since a small volume of liquid can be readily recirculated using filters to prevent plugging of the core. EXPERIMENTAL The oven-dried core is weighed and is then completely saturated with brine

Jan 1, 1950

HAVING previously shown you how ores are found and mined, and also how they are prepared and disposed for smelting, and then how the blast furnaces and other furnaces are made for purging their earthiness, all this would be as nothing if I did not proceed to show you the method of smelting them. Therefore, in the present chapter I wish to show you how you must proceed in this very important operation, telling you all I have seen and also how much work with this kind of blast furnace I have done or directed. For this reason I tell you first to take by weight or measure the quantity of ore that you wish to smelt and, particularly if it is a kind that contains silver, break it into small pieces about the size of [52v] beans. If the ore had previously needed evaporation by fire or cleaning by washing, you will have had this done well and have had it properly prepared by a master sorter or others. A layer of this is arranged on a bed of planks, bricks, or flat stones in front of the blast furnace and its companion is placed on top, then a quarter part of galena or a third if you can obtain it. Then an equal part of crushed iron slag or slag from the same or different ore is added. These materials are spread in layers one above the other. When the blast furnace has been constructed as taught above, correct in all its parts, and is full of well-kindled burning charcoal, then fill it up with charcoal and admit water to the bellows machine. When you see that it is well kindled again from this wind and that the flames begin to come out forcefully on top, work it down with a little rake and fill it up again. Then the pannier is filled with new charcoal, the blast furnace heaped full, and another basketful of the said composition of ore is also put on top. Proceed in this way, continually adding charcoal and ore as long as you have any, or as long as you wish to keep up the work, maintaining the blast furnace always full, or continuing in this way until the bottom of the blast furnace is filled with melted materials. Decide this by judgment, or by seeing through the mouth of the tuyère where the wind of the bellows enters that they are level with this. Then with an iron tool open the hole that was left as an outlet in front of the blast furnace and allow all the metal with its slag to run out. These two things, flowing through the chan-

Jan 1, 1942

By Cornelius F. Kelley

EVERY man connected with the mining industry should take a significant pride in the fact that he belongs to an industry and to a profession that, from the beginning, has been constructive. The miner digs his ore and he gives the metal to art, to industry, and to commerce. The nature of our business is destructive only in that we deal with a wasting asset. That should be a source of great pride to those who belong to the profession. But unfortunately, the product of our mines, our smelters, and our re- fineries does not always go to constructive purposes. There are times when, in the administration of the affairs of men, our product chiefly goes to purposes which are destructive. When we look upon the panorama of horror that is being enacted throughout the world today, we wonder whether any effort toward the development of civilization and culture and education and well-being has been worthwhile. We are appalled to see the things that have been developed, through the application of science, toward progress and efficiency, now used for the catastrophic destruction of those things which are the most valuable that man has built. We must find hope that this is but an episodic thing; that it must, in the infinite wisdom of the Almighty, usher in a period of peace and progress, of civilization and development that will make man's existence upon earth worthwhile.

Jan 1, 1941

By E. Cortese

Phosphate occurs in many places in Egypt, in two main zones: one in Upper Egypt, along the Nile Valley, principally on the right side, and one near the Red Sea coast. In the Nile zone, the principal layers of phosphate rock are to be found: in the mountains east of Mahamid (right side of the valley); in the hills near Sibaiya, also called Sebaieh (both sides); in the hills of Agula, Hagaza and Gurn (right side); and further on, along the camel road leading from Kena to Kosseir, a few miles east of Legheita's Oasis. Following that track, after having crossed the watershed, underlain by rocks like granite, serpentine, porphyry, and diabase, one comes again to the Cretaceous formation containing considerable quantities of phosphate, at Gebel Duwi, Gebel Nakheil, and Gebel Kosseir El Kadim, not far from the coast. More to the north, in the hills near Safaga Bay (Um El Uettat El Wasif) is another rich bed of the same formation. There are reports of phosphate existing near Suez and in the Sinai peninsula, and possibly some other zones can be traced or discovered in the future. The mines are well developed on the right bank of the Nile at Sharawna (near Sebaieh Station) and along the Red Sea coast, at Safaga and near Kosseir. Prospecting work has been done at Gebel Duwi, Gebel Gurn, Agula, Hagaza, and near Mahamid. The phosphatic formation in Egypt is quite variable, not only from place to place, but even within small areas. The phosphate is all of Cretaceous age, as is proved by the fossils found in it. It is considered to belong to the Campanian or, more appropriately, to the Maestrichtian series. The principal fossils are: Alectryonia Villei Coq. sp.; Roudereia Aures-sensis Coq. sp. = R. Drui Mun. Chalm.; Trigonoarca multidentata, Newton.; Cardita libyca, Zittel; Libycoceras Ismaely, Zittel; Nautilus sp.; Ancystrodon libycum Dam.; Corax pristodontus Ag.; Lamma biauriculata Zittel sp. Above the Maestrichtian beds, we have the Danian series, unconform-ably covered by Lower Eocene beds. Under the phosphate is a grayish marly clay, and beneath this, bluish-gray scaly shales resting on the Nubian sandstone (Santonian).

Jan 1, 1918

By W. W. Colpitts

To me, as to many other students of railroad needs, the necessity for reducing the dead weight in railroad rolling stock, both passenger and freight, has been apparent for, many years. The problem of weight reduction of passenger cars is so entirely different from that of freight cars, is so much more to the fore at the present moment and would seem to be so much nearer solution, that I shall confine myself in these remarks to the former. On the surface of things there would appear to be no close association of thought between the decline in traffic on the railroads, which is largely responsible for their present deplorable financial condition, and new metal alloys. It sounds like a trick riddle a school boy might propound to his parents. But that there is a relationship between the two, and one that bids fair to be of great mutual benefit to the railroads and the makers of .high-strength metal alloys, I hope I shall be able to show before I have finished. To make the situation understandable to those who are not entirely familiar with the problems of railroad management, and, who feel that the railroads have not moved as rapidly as they should in the direction of greater use of newer materials and newer appliances, I shall have to review briefly the course of recent railroad history. If in this part of my talk I seem to the professional man to be a little off key I feel sure my remarks will be fully appreciated by the business man who cannot understand why he is not making better headway in selling things to the railroads. To do this I shall have to go back to war times for a moment.

Jan 1, 1936

By John D. Siddle

Efficient energy utilization in the electrolytic zinc process, relative to other zinc processes, is one of the reasons for its wide adoption in recent years. Designers and operators of electrolytic zinc plants have pioneered process improvements, new equipment, and operating techniques to conserve energy. As energy costs advance still higher in the future, and competitive pressure against the less efficient producers increases, these or alternative energy-saving methods will be looked upon as a necessity for economic survival. Estimated energy savings which may be achieved by various equipment and techniques are included.

Jan 1, 1977

MEETING OF SAN FRANCISCO SECTION Twenty members were present at the meeting of the San Francisco Section, May 20, 1919. Chairman Bradley being in Alaska, vice-chairman, T. A. Rickard, presided. Prof. Frank H. Probert gave a short account of the activities of the governmental commission, consisting of himself, George S. Rice, and F. G. Cottrell, which recently visited Europe, and studied the coal, iron, salt, and chemical industries. When the work is finished reports will he issued. He gave a resume of the history of. the changes in nationality of Alsace-Lorraine and 'described the importance of the region for coal, iron, and potash. With the return of these provinces France will have an annual output of more iron ore than she has coke to smelt it with; hence, the importance of the Saar coal field. With these new mines France will take the predominant position in the iron and steel-industry formerly held by Germany. Many details were given of the devastated mines of France, and of their former value, production and the destruction that overtook them. Noteworthy is it that much of the damage was done as late as Oct. 28, 1918, for the express purpose of ruining the country industrially. The damaged area of the Valenciennes coal basin embraced twenty-four concessions, three were damaged by artillery bombardment, but have resumed operations since the' armistice, nine had their surface: equipment destroyed by battle, pillage, and sabotage, while twelve concessions at the eastern-end of-the field suffered from wilful, systematic destruction. Of the 285 shafts in the district, 172 were flooded either by: turning surface streams into them, or, by wrecking the cuvellage; thus, admitting water and quicksand from the water-bearing strata above the coal measures. Two hundred and thirty-five surface plants were damaged, many of them to such an extent that they must be scrapped. These properties gave employment to 135,000 men before the war and, even admitting the remote possibility of getting workmen, the terrible destruction and devastation makes housing and living a difficult problem. It will probably be from 3 to 5 years before the mines are drained and information obtained as to underground conditions; to attain the pre-war output may require from 12 to 15 years.

Jan 8, 1919

By J. Fred Johnson

MORE ORE is mined in the Bingham District than in any other mining district in Utah. In addition to the open-pit operations of the Utah Copper Co., there have been, many large underground mines. Until recent years the principal production was from the Jordan and Commercial limestones, but in the last eight years valuable ore deposits have been developed in the so-called alphabetical or "A," "B," "C," and "D" limestones, mainly by the U. S. Smelting, Refining & Mining Co. The value of these developments has led the company just mentioned to acquire large holdings in the district and within the last year to install at the Niagara shaft a hoist capable of going to a vertical depth of 4000 ft., or 1800 ft. deeper than the present lowest level. Ore from Bingham has been the chief factor in enabling the

Jan 1, 1934

By W. Tempelaar Lietz

The Ten Section oil field is located in the San Joaquin Valley in Kern County, California. about 12 miles southwest of Bakersfield in Township 30 South, Ranges 25 and 26 East. The accumulation is in a low relief anticlinal dome and has a productive area of approximately 2,200 acres. Discovered in 1936 as a result of seismic work, it was the first field on the floor of the Valley to obtain production. It had a small primary gas cap, and since its inception has been produced by depletion with controlled withdrawal from the gas cap to minimize blowthrough. STRUCTURE AND STRATIGRAPHY The Ten Section structure is an elongated anticlinal dome with flank dips of only about 7 degrees. A map of the field, now fully developed, and a composite log are shown in Figs. 1 and 2. Contours shown on the map are on the top of the first zone, or Marker XA as indicated on the composite log. As shown, the field has a productive closure of only some 350 feet, and there apparently is no faulting in the reservoir. The productive measures in Ten Section are of Upper Miocene age and are known as the Stevens sand. They contain thin, irregular shale or siltstone streaks which vary considerably in stratigraphic position and thickness and apparently are rather discontinuous. As a result, individual sands and shales cannot be correlated over any appreciable area, which makes it difficult to subdivide the sand body into separate zones which are distinct throughout the field. However, there are two fairly persistent siltstone bodies that at the time of development were considered to divide the productive measures into three - zones. The first, or uppermost zone is productive over the entire field and has an average thickness of 180 feet, of which some 65 per cent is sand. It had a primary. gas cap in the crestal area with an areal extent of 930 acres. The second zone has a productive area somewhat smaller than the first zone, but it did not have any original gas cap. It has an average thickness of about 360 feet, of which 55 per cent is sand. The third zone has a very limited areal extent and a maximum productive thickness of 100 feet, of which 80 per cent is sand. Recently, a deeper oil accumulation, termed the "53" sand, was discovered, but it is not discussed in this analysis. In the first and second zones the water table was at 7,980 feet subsea, while in the third zone it was at 8,080 feet subsea. RESERVOIR CHARACTERISTICS Sand Characteristics The Stevens sand in Ten Section is hard and well consolidated, and numerous wells were cored for core analysis. Core data on four representative wells are shown, plotted beside the electric logs in Figs. 3 to 6. The average porosity is 20 per cent, with porosities ranging from 15 to 30 per cent. It is estimated, from cores taken with oil base muds, that the interstitial water content is about 40 per cent. The average weighted permeability is approximately 140, with measured permeabilities ranging from 10 to 3,000 md. As might be expected with practically no correlation of individual sand

Jan 1, 1949

By W. Tempelaar Lietz

The Ten Section oil field is located in the San Joaquin Valley in Kern County, California. about 12 miles southwest of Bakersfield in Township 30 South, Ranges 25 and 26 East. The accumulation is in a low relief anticlinal dome and has a productive area of approximately 2,200 acres. Discovered in 1936 as a result of seismic work, it was the first field on the floor of the Valley to obtain production. It had a small primary gas cap, and since its inception has been produced by depletion with controlled withdrawal from the gas cap to minimize blowthrough. STRUCTURE AND STRATIGRAPHY The Ten Section structure is an elongated anticlinal dome with flank dips of only about 7 degrees. A map of the field, now fully developed, and a composite log are shown in Figs. 1 and 2. Contours shown on the map are on the top of the first zone, or Marker XA as indicated on the composite log. As shown, the field has a productive closure of only some 350 feet, and there apparently is no faulting in the reservoir. The productive measures in Ten Section are of Upper Miocene age and are known as the Stevens sand. They contain thin, irregular shale or siltstone streaks which vary considerably in stratigraphic position and thickness and apparently are rather discontinuous. As a result, individual sands and shales cannot be correlated over any appreciable area, which makes it difficult to subdivide the sand body into separate zones which are distinct throughout the field. However, there are two fairly persistent siltstone bodies that at the time of development were considered to divide the productive measures into three - zones. The first, or uppermost zone is productive over the entire field and has an average thickness of 180 feet, of which some 65 per cent is sand. It had a primary. gas cap in the crestal area with an areal extent of 930 acres. The second zone has a productive area somewhat smaller than the first zone, but it did not have any original gas cap. It has an average thickness of about 360 feet, of which 55 per cent is sand. The third zone has a very limited areal extent and a maximum productive thickness of 100 feet, of which 80 per cent is sand. Recently, a deeper oil accumulation, termed the "53" sand, was discovered, but it is not discussed in this analysis. In the first and second zones the water table was at 7,980 feet subsea, while in the third zone it was at 8,080 feet subsea. RESERVOIR CHARACTERISTICS Sand Characteristics The Stevens sand in Ten Section is hard and well consolidated, and numerous wells were cored for core analysis. Core data on four representative wells are shown, plotted beside the electric logs in Figs. 3 to 6. The average porosity is 20 per cent, with porosities ranging from 15 to 30 per cent. It is estimated, from cores taken with oil base muds, that the interstitial water content is about 40 per cent. The average weighted permeability is approximately 140, with measured permeabilities ranging from 10 to 3,000 md. As might be expected with practically no correlation of individual sand

Jan 1, 1949

By W. B. Coleman

Considerable discussion on the effect of iron and steel scrap in blastfurnace burdens was presented in the January, 1927, issue of Mining and Metallurgy. Therein the question is asked as to what causes the difference in physical properties of pig irons where the chemical analyses are practically the same. This point no doubt has been noticed by a number of furnace operators, but several years ago very little thought was given to it. The foundries purchased pig iron, had it analyzed and found it to be within their specification. The castings made from this iron at times would be satisfactory and at other times hardness and shrinkage would occur. Since the iron was chemically correct the foundries generally were at a loss as to what to do. They changed their method of melting in the cupola and in some cases this corrected the trouble. In some instances the foundry would continue eliminating a brand of iron until the castings produced were satisfactory. Through this process of elimination they would finally arrive at the conclusion that a certain brand of iron was causing the trouble. During the course of this elimination minor changes might have been made in the melting and in the end satisfactory castings were secured without discovering any definite reason for the trouble. Frequently the foundries blamed the manufacturer of the pig iron although the seat of the trouble was in their own method of melting. I have in mind one foundry in particular that was using three brands of pig iron for producing their castings and their losses were rather high. Three entirely new brands of iron were substituted in the charge and still the losses continued. Even after using six brands of pig iron the management felt that the pig iron was the cause. The difficulties encountered in the melting of iron in the cupola, over the past several years, reflect in a great many cases on the operation of the cupola. At different times certain brands of iron were unsuitable for producing a certain class of castings, but at the same time one could see no reason why the iron should be considered abnormal. Irons from furnaces where production and low cost are the main factors that are being used in foundries produce in most cases harder cast-

Jan 1, 1927

By K. Huessener

INTRODUCTION THIS paper attempts a survey of the principles involved in the com¬bustion of blast-furnace gas in boilers and stoves. I do not expect to be able to give much information which is actually new, since the laws and methods of calculation pertaining to this problem are contained in a number of handbooks; but, so far as I am aware, they have nowhere been treated exclusively with reference to this one problem of gas economy. The road which I follow is less that of strictly scientific research than that of the practical engineer, faced by operation problems which require a. quick solution by easily accessible means without a prolonged search in scientific handbooks. For this purpose I give a number of tables and diagrams, as well as the results of many years' practical working experience as combustion engineer, which I trust will prove useful to my readers. HISTORICAL Considering the tremendous efforts made during the last 15 years to increase the efficiency of all kinds of power plants, it is highly surprising that until a comparatively very recent period, progress in the economical combustion of blast-furnace gas has been so slow. The explanation generally put forth, that fuel has been so cheap that it was hardly worth while to bother about this economy, will not hold good, for the greatest trouble was taken to improve the combustion of coal and to reduce the consumption of steam. The most plausible explanation appears to be the general impression, held as an accepted fact, that gas, especially hot, uncleaned, blast-furnace gas, was not a good boiler fuel. Many managers of high repute had tried unsuccessfully to improve the conditions of its use, and the dictum went forth that efficiencies of over 60 per cent., particularly with high loads, were impossible. This was the situation not only in the United States, with very cheap fuel, but also in Europe, where fuel prices are twice and three times as high.

Jan 2, 1916

By Vernon F. Swanson

An equation has been developed which will permit the direct determination of free settling velocity of any sized particle encountered in mineral benefici-ation. The equation is based on Newton's Law with the friction factor defined as a function of the laminar boundary layer. Development of the equation is described first from an empirical trial-and-error approach. Examples are given of actual settling data from the literature versus calculated data to prove the validity of the new equation. Newton's law of resistance of a fluid to flow around a sphere is expressed in Eq. 1. Free settling velocities can be determined by setting Eq. 1 equal to the gravitational force on a particle and solving for V. Experience has shown that when the solids are greater than 1 mm in diam, or when Reynold's number for the system is greater than 800-1000, the friction factor term, fD, essentially becomes a constant, and Eq. 2-b becomes Newton's equation for free-settling and is applicable under the conditions stated. Another special condition exists for particles smaller than 0.05 mm or when Reynold's number for the system is less than three. In this case fD=24/NRor24µ/pL,dV,. Eq. 2-b can then be rewritten as

Jan 1, 1968

By R. A. Deju, R. B. Bhappu

The basic structural unit of all silicate minerals is a tetrahedron with a silicon atom at the center and four oxygen atoms at the corners. The oxygen-silicon distance is about 1.6 & and the oxygen-oxygen distance about 2.6 &. The different types of oxygen-silicon frameworks in the various silicates are based entirely on the combinations of the tetra-hedral oxygen-silicon groups through sharing of oxygen atoms. In recent years, infrared spectroscopy has permitted estimation of the ratio of the ionic character of the oxygen-silicon bond to be a few times that of the oxygen-carbon bond and the ratio of electro-negativity of the two bonds has also substantiated this finding. On this basis, it is generally accepted that the oxygen-silicon bond is the strongest one occurring in silicate minerals. As the oxygen-silicon ratio increases from quartz to the olivines, a greater percentage of the oxygen bonding power is available for bonding to cations other than silicon. Hence, with an increasing oxygen-silicon ratio, there is increasing oxygen-to-metal bonding. Upon the fracturing of a silicate mineral crystal, the oxygen-metal bond, which is almost entirely ionic in character, should break more easily than the stronger oxygen-silicon bond, resulting in a greater number of unsatisfied negative forces on the surface. If, then the mineral is immersed in a liquid containing hydrogen ions, these negative forces should tend to be neutralized by hydrogen ions from solution, resulting in a change of the pH of the solution. An increase in the degree of adsorption of hydrogen ions is to be expected as the oxygen-silicon ratio in the crystal structure increases. This study attempted to correlate the oxygen-silicon ratio for various representative silicate minerals to the adsorption of hydrogen ions. Experiments to determine the effect of surface area on this adsorption and to investigate the effect of surface iron were also conducted. It is believed that such studies of the surface properties of silicate minerals will supply pertinent information about their behavior in froth flotation systems. EXPERIMENTAL PROCEDURE Ion Exchange: Carefully selected, hand-picked samples of the minerals investigated were dry-crushed in a ceramic ball mill and sieved to obtain a minus 100 plus 200-mesh sample. The sized samples were then run through the electro-magnetic separator to remove any iron-bearing particles. A 10-g sample of each mineral was placed in 100 ml of freshly deionized water previously adjusted to a pH of 3.50 with HCl. The beaker containing the sample and the water was placed under a bell jar from which the air was displaced at once by nitrogen gas from a tank. All experiments were carried out in a nitrogen atmosphere. The sample and solution were stirred gently but continuously during the entire experiment, the stirring speed being kept about the same for all runs. Changes in pH were followed with a Beckman Zeromatic pH meter and recorded on a

Jan 1, 1967

By S. Chander, D. W. Fuerstenau

The inherently sluggish nature of the reactions involving sulfide minerals, particularly molybdenite, in aqueous solutions under ambient flotation conditions make their investigation complicated and difficult. Since the physicochemical nature of sulfides is known to be controlled by electrochemical reactions, a number of attempts have been made in the past to study sulfide mineral-collector interactions through rest potential and electrode polarization measurements. The purpose of the present investigation was to study the interaction of potassium diethyldithiophosphate (KDTP) with molybdenite. In the present investigation of the interaction of KDTP at the molydenite surface, molybdenite electrode rest potential measurements and electrode polarization behavior were experimentally determined under various solution conditions. The standard reduction potential for the equilibrium between dithiophosphate ions (DTP-) and bis(diethoxythiophosphoryl)disulfide (DTP) [(DTP). + 2e :i7-± 2DTP- (1)] can be evaluated from the electrode rest potential measurements on a platinum electrode in deoxygenated KDTP solutions saturated with freshly prepared (DTP)2. Experimental A platinum wire was used as the electrode for potential measurements. Prior to each measurement the elec-

Jan 1, 1975