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By D. M. Jamieson, M. P. Pearse, E. R. A. Plumstead

In 1948 the shaft sinking record in the Republic of South Africa was held by the Van Dyk Consolidated Mines Ltd. for a ventilation shaft with a footage of 461 ft sunk during the month of August 1941. This record remained for some ten years; but in the ensuing nine years it was broken no less than 13 times. Table I gives shaft sinking records throughout the world for the 21 years, 1940 to 1960. History shows that the wide, deep, timbered rectangular shaft had passed its peak of popularity by 1948, although it still had a great deal to commend it, both from the sinking and operational points of view. In sinking, it is easy to clean manually, and water can be handled by bailing when wet ground has to be negotiated; its shape also lends itself to equipping concurrently with sinking. In operation it provides the most convenient "in line" hoisting arrangement, and if the ventilation requirements so demand, it offers the simplest solution in that it can be divided into upcast and downcast sections. Furthermore, in the case of a multi-level mine, the shaft compartments can be reduced conveniently if the full area of the shaft is not required to serve all levels.

Jan 4, 1963

By Ferid Kromer

This paper is the first in a series which will describe geology, mining methods, and production costs of some of Turkey's more important minerals. In this paper the economically significant minerals-chromite, meerschaum, and magnesite-of the Tastepe district are described. The cost data presented are believed by the author to be the first made public on Turkish chromite mining.

Jan 1, 1950

By H. W. McQuaid

IT IS usually assumed that chemical specifications are sufficient for steel to be used for case carburizing, and if the steel analyzes within the ordinary limits specified for steel for this purpose, no difficulty traceable to the steel used should be encountered in obtaining satisfactory results in the case carburizing and hardening. Much work has been done to determine the effect of various alloying elements on the rate of carbon penetration, etc. but, to our knowledge, little if anything has been published in regard to the effect of the quality of the steel on the final results in the hardening of case-carburized steel parts. The writers believe that the structure of the case both before and after quenching is greatly affected by the actual condition of the steel itself as made, and that for good results in the case-carburizing and hardening departments, the steel should be of the best possible quality as regards non-metallic impurities. It is the purpose of this paper to prove that the presence of excess dissolved oxides in the steel, as made in the melting furnace, affects permanently the results obtained in carburizing and hardening and that it is possible that the presence of dissolved oxide can result in total unfitness of low-carbon steel for, case hardening purposes. When races and rolls for roller bearings are made from a low-carbon steel, case carburized and hardened, it is of primary importance that the results of this treatment be of the highest quality. It is necessary, therefore, that in the case-carburizing work each detail be rigorously checked to avoid any defects which would cause the loss of much time and material. The case carburizing with which this paper deals was done in under-fired oil furnaces. The temperature of each furnace is controlled by means of a platinum platinum-rhodium thermocouple, in connection with a potentiometer indicator and potentiometer recorder. The temperature of each furnace is registered every 15 min. by an operator, who is continually checked by the automatic recorders.

Jan 2, 1922

By Frank A. Hill

A visitor to the Northern anthracite coal-field in 1844 wrote: " History and song have hallowed the valley of Wyoming, and everything pertaining to it seems wrapped in an atmosphere of romance." Song and history have since been almost forgotten in the rush of enterprise and business energy, while the invested capital which has built 160 colliery plants, producing last year 17,031,826 tons of coal and giving employment to 50,000 men and boys, lends an atmosphere the inspiration of which is the very sustenance of prosperity and progress. The fundamental cause of this great valley's financial strength, however, rests on the fulness of its mineral wealth. Its mountains surround and its cities are built upon anthracite coal. Its foundation, physically, financially and socially, is coal. Its geology has governed its growth and developed its greatness. In 1768, ten years, prior to the celebrated Wyoming massacre, two Connecticut Yankees, named Gore, settled near Wilkesbarre, Luzerne County, and, burning Pennsylvania anthracite in their blacksmith's forges, were the first to utilize it as a fuel. Its first use in the household was also at Wilkesbarre, where, in 1808, Judge Fell burned it in an open grate. Carbondale, Wilkesbarre, and Scranton were early recognized as the coal centers of the field.

Jan 1, 1887

By Clarence Balke

SMALL buttons of fused tantalum have been produced by are fusion in a vacuum, by drawing an arc between sticks of pressed tantalum and a tantalum-faced water-cooled copper block. However, ingots of appreci-able size can be produced only by the heat-treatment of bars pressed from powder. The following outline covering the production of finished bars of tantalum by the methods of powder metallurgy is also used for the production of columbium, taking into account the difference in the melting points of these two metals. PRESSING THE POWDER With possibly a few exceptions, a pressing operation is one of the essential steps in the practice of powder metallurgy. In fact, the author's experience with a number of high-melting-point metals and with numer-ous types of hard carbide compositions has led him to believe that this operation is often one of the most important in the- entire process, and frequently one of the most difficult to carry out in a satisfactory manner. Defects clue to improper pressing can readily lead to a defective finished product. It is the author's opinion that rarely is a bar or other article pressed from metal powder in such a way that all parts of the piece are uniformly pressed. The nearest approach to uniformity of pressing is possibly attained when the powder is contained in a flexible receptacle, such as rubber, and is pressed under a liquid by hydrostatic pressure. However, this method is not generally applicable. Hydraulic pressing in steel dies where one or two punches are forced into the die must usually be resorted to. As the pressure in such a die is built up, the powder begins to cling to the walls of the die with a tenacity dependent upon the nature of the powder, and this results in a bridging action, so that the layers of powder adjacent to the moving punch are pressed more heavily than those further removed in the mass. Frequently, as the pressure is carried higher, there may be a mass slippage of the powder upon itself, with the result that slip cracks are formed within the pressed

Jan 1, 1938

By Hannu Penttila, Harrison R. Cooper, Olli Mattila

Two approaches to automated operation in metallurgical processes involve the conventional analog control or, more recently, digital control. The expanding use of digital controls applied to process automation is a comparatively new development. Several current technical reports describe digital control systems in concentrator grinding control, 1, 2, flotation, 3 and smelter operations. 4,5 The principle factors influencing trends to digital control are:

Jan 10, 1976

By Alvin Kaufrnan

This chapter will deal with the policy issues relating to mineral land disposal. The first portion of the chapter will discuss in general terms the legal systems utilized in disposing of mineral rights and the major problems encountered; the second section will comprise an analysis of the policy alternatives with emphasis on the pricing aspects. In this section, we are not attempting to provide a legal text, but simply to outline very briefly and sketchily the details of the systems. More detailed information can be obtained by contacting the appropriate governmental agency for specific information. Mining laws throughout the world are based on two major legal groupings: English Common Law and the Civil Law. These basic systems are often modified by Islamic Law and by negotiated -mixtures of these. Under English Common Law, which is embraced by the United States, Canada, and many of the members of the British Commonwealth of Nations, individuals can hold property and can extract minerals from it. The owner can dispose of minerals as he sees fit, either through contract, deed, or whatever other system is appropriate. CIVIL LAW Under Civil Law (also known as Regalian Law), mineral ownership is normally placed in the state, regardless of who owns the surface. This legal system applies in most European countries and their former colonies. It is derived from Roman law. The mineral deposits, thus, are worked under concessions. Most countries use a negotiated concession system and sometimes a combination of negotiation and competitive leasing. The negotiated system has advantages as well as disadvantages for both government and industry. In a system where the government administratively determines who is to get what, the concessions are normally large. Frequently they range up to several millions of acres and involve a considerable investment on the part of the concessionaire. There is no duplication of effort on the part of producers to obtain information, since a single concessionaire controls a given area. Consequently, less money is spent in toto because several prospective operators are not required to seek the same information. The system also has the advantage to the industry of permitting the concessionaire to select and retain the best producting area. Thus, major developmental expenditures are made on the production unit only, with a resulting reduction in the risk factor. The large initial size of the concession also minimizes the possibility of expending a large bonus payment for a barren property. The major governmental advantage of a concession is its flexibility in accomplishing other national objectives. For example, a lease could be negotiated at less than fair market value, but requiring substantial de-

Jan 1, 1976

FRANK N. SPELLER,? Pittsburgh,. Pa.-Mr. -Hayward's paper again draws attention to the fact that copper in steel is not the enemy that a good many of us it one time thought it was. He shows clearly that steel with over 0.75 per cent. of copper is as dependable, under the :conditions which he describes, as the same steel without copper. I might add that you-can weld copper-steel- satisfactorily up to that point; in fact, we have succeeded in welding pipe by the lap weld process up to 1 per cent. copper. Notwithstanding the date that have been presented on the effects of copper on the physical properties and corrosion of steel, a maximum copper limitation is still found in many specifications. In some cases the limit is extremely low, such as below 0.05 .or 0.03: per cent., or thereabout. That is a relic of days gone by, and I think the practice should be discouraged. E. F. CONE, New York; N. Y.-Not so many years ago steel-casting makers were very particular as to the amount of copper that existed in the pig iron that they used. They would not use copper-bearing pig iron unless mixed with non-copper iron. I do not know what the practice now is in the particular foundry where I was metallurgist at one time,

Jan 4, 1918

By R. B. Gordon, D. A. Koss

Ultrasonic-atlenuation changes due to the formation of free dislocations have been observed during tensile tests of magnesium and LiF single crystals and samples of polycrystalline Results on the LiF and samples are similar: A preyield attenzration increase is observed which, however, be-corlzes smaller as the magnitude of the drop in load al yielding increases. This indicates that the yield point observed in these materials is due to dislovation rather than dislocation unpinning and that the initial density ' free dislocations must be low if the yield point is to be sharp,. Tests on the magnesium ere conducted at both 27" and 200C. Magnesium has the unusual property that the yield drop is larger at the higher test temperature and is accomplished by a decrease in attenuation. The latter is due principally to the temprovary pinning of detained dislocations by highly solute atoms. After strain aging., a stress as low as 0.3 bur suffices to unpin dislocations; microstrain measuements of sufficient sensitivity should. reveal plastic flow at stress levels this low IN another paper,' we describe the technique of simultaneously observing ultrasonic-attenuation changes and plastic microstrain during deformation of spher-oidized carbon steels. Changes of ultrasonic attenuation indicate damping effects caused by the oscillation of long, freely moving dislocation segments. Simultaneous microstrain measurements are used to indicate total dislocation motion. The dislocation-damping observations are most useful in the study of the early stages of deformation where the dislocation density is low and the plastic strain is small and relatively difficult to measure. Particularly interesting results are found in materials which display sharp yield points. Observations of these phenomena are reported here for three materials: single-crystal LiF and magnesium, and poly crystalline molybdenum. EXPERIMENTS Dislocation-damping effects were observed by measuring changes in acoustic attenuation with the ultrasonic-pulse method. The end faces of each of the specimens were ground flat and parallel and a quartz 10 Mc per sec, x-cut transducer was attached to one face. The bonding agents used were: a) "Nonaq" stopcock grease with magnesium, b) beeswax with LiF, and c) salol with molybdenum. With the LiF, the best acoustic signals were obtained at 45 and 50 Mc per sec; all other measurements reported are at 10 MC per sec. The Sperry Ultrasonic Attenuation Comparator2 was used to measure attenuation changes. In the

Jan 1, 1967

By John M. Hartman

The high temperature of the blast of modern furnaces renders it desirable that the pipe conveying the blast into the furnace crucible shall transmit and radiate as little heat as possible. To accomplish this, the pipe shown in the accompanying sketch was devised and patented. It consists of a slide-valve, leg-pipe, and belly-pipe, which are held together and to the tuyere by a system of levers and links. The slide-valve is superior to the old throttle-valve. The legpipe is formed of two thicknesses of wrought-iron pipe, with a space of half an inch filled in with clay and brick. The belly-pipe is made in the same way as the leg-pipe, and terminates in a globe face to suit the tuyere. The quarter turn is made extra thick, of cast iron, and the cap on the end is lined with clay also. The catches, A, B, C, are merely for convenience in putting the pipe together. The joints D and E are globe faces, and allow the pipe to adjust itself to any angle. The eye-piece is made of violet glass, which cuts off the glare from the bright coals in the furnace and allows a close examination of the interior, so that any water dropping or vapor can be detected. The glass does not become coated with dirt, like mica. Since good running of furnaces is shown by a bright tuyere, it is necessary to have a good eye-piece to examine them. To detach the pipe, a man lifts the weights, the side rods are then slipped off the bell crank under the quarter turn, the link under the belly-pipe is unhooked, and the pipe carried away. The same process is reversed to put the pipe together. The nozzle is changed by taking off the cap, G, drawing the nozzle through the belly-pipe, and inserting another. In this way the change can be made quickly, without taking down the pipe. On the old tuyere pipe bolts with brass nuts were used, which burned up and gave trouble. In other cases key-bolts were used, making it difficult to adjust the pipe. Bolts make too rigid a joint, and there is no provision for movement from contraction or expansion. As the temperature of the blast increases there is more expansion, and where rigid joints are

Jan 1, 1879

By John M. Hartman

THE high temperature of the blast of modern furnaces renders it desirable that the pipe conveying the blast into the furnace crucible shall transmit and radiate as little heat as possible. To accomplish this, the pipe shown in the accompanying sketch was devised and patented. It consists of a slide-valve, leg-pipe, and belly-pipe, which are held together and to the tuyere by a system of levers and links. The slide-valve is superior to the old throttle-valve. The leg-pipe is formed of two thicknesses of wrought-iron pipe, with a space of half an inch filled in with clay and brick. The belly-pipe is made in the same way as the leg-pipe, and terminates in a globe face to suit the tuyere. The quarter turn is made extra thick, of cast iron, and the cap on the end is lined with clay also. The catches, A, B, C, are merely for convenience in putting the pipe together. The joints D and E are globe faces, and allow the pipe to adjust itself to any angle. The eye-piece is made of violet glass, which cuts off the glare from the bright coals in the furnace and allows a close examination of the interior, so that any water dropping or vapor can be detected. The glass does not become coated with dirt, like mica. Since good running of furnaces is shown by a bright tuyere, it is necessary to have a good eve-piece to examine then. To detach the pipe, a man lifts the weights, the side rods are then slipped off the bell crank under the quarter turn, the link under the belly-pipe is unhooked, and the pipe carried away. The same process is reversed to put the pipe together. The nozzle is changed by taking off the cap, G, drawing the nozzle through the belly-pipe, and inserting another. In this way the change can be made quickly, without taking down the pipe. On the old tuyere pipe bolts with brass nuts were used, which burned up and gave trouble. In other cases key-bolts were used, making it difficult to adjust the pipe. Bolts make too rigid a joint, and there is no provision for movement from contraction or expansion. As the temperature of the blast increases there is more expansion, and where rigid joints are

Jan 1, 1879

By Eugene N. Cameron

Graphite is the hexagonal form of crystal-line carbon. It is found in nature locally as tabular crystals but occurs mostly as disseminated flakes, foliated, platy, or fibrous masses, or microcrystalline compact to earthy material. Graphite is characterized by its gray to black color, metallic luster, black streak, perfect basal cleavage, softness (H = 1-2) and unctuous feel. It is sectile and flexible and has a specific gravity of 2.1 to 2.3. It is an excellent conductor of heat and electricity and is inert to ordinary chemical reagents. It melts at a temperature of about 3500°C and vaporizes at a temperature of about 4500°C. In the presence of oxygen it oxidizes to CO2 in the temperature range 600° to 700°C, but it is stable at ordinary temperature and markedly resistant to chemical weathering. Although some natural graphite is nearly 100 pct pure carbon, most contains mechanical impurities of various kinds; quartz, biotite, muscovite, pyrite, iron oxides, and feldspars are the most common. Commercial graphite products have a wide range of graphite content, but the better grades contain 80 pct graphite or more. Both natural and manufactured (artificial) graphite are used in industry. Natural graphite products are divided into two broad categories based on grain size. Graphite composed of visible crystals is called "crystalline" graphite, whereas graphite so fine-grained that it is not visibly crystalline is termed "amorphous." The distinction is arbitrary, for all natural graphite is crystalline, and all gradations between the two commercial categories are known. Within the two categories the terminology used in industry is confusing and not entirely consistent. Crystalline graphite comes from two principal types of sources. The first consists of rocks containing disseminated flakes of graphite. This source yields the "flake graphite" of industry. The second comprises vein deposits of graphite, of which those in Ceylon are the most important and furnish the Ceylon graphite of industry. Amorphous graphite comes from any of a variety of sources, including some of those that yield crystalline graphite. Manufactured graphite is made by electric furnace processes, mostly from petroleum coke. Occurrence and Distribution of Graphite Deposits GENERAL Graphite is widely distributed in nature, occurring in igneous, sedimentary, and metamorphic rocks, and even in nickel-iron meteorites. Graphite deposits of economic interest, however, occur mostly in metamorphic terranes. Five principal geologic types of deposits are recognized: 1. Deposits consisting of flake graphite disseminated in metamorphosed siliceous sediments. 2. Deposits consisting of flake graphite disseminated in marbles. 3. Deposits formed by thermal or dynamothermal metamorphism of coal or other highly carbonaceous sediments. 4. Vein deposits of the Ceylon type. 5. Contact metasomatic or hydrothermal deposits in marble. DEPOSITS IN METAMORPHOSED SILICEOUS SEDIMENTS Deposits consisting of flake graphite disseminated in metamorphosed siliceous sedi-

Jan 1, 1960

By C. W. Vaupell

The Huitzuco mines lie in north central Guerrero, Mexico; production has been about 90,000 flasks of quicksilver since 1873. Near-surface ores fill extinct mud geysers and the deep deposits are chambered veins, stock-works in brecciated blocks, and replacements in limestone. The epigenetic minerals livingstonite, stibnite and sulphur occur in limestone, gypsum and dolomite through a developed vertical range of 260 meters. The deepest workings expose an increased amount of stibnite, which probably indicates that the lower limit of mercury mineralization is being approached. A resurgence of heat and water formed geysers over an extended area after the period of mercury mineralization. Mud geysers, which are situated, in the outcrops, contain the secondary mercury minerals, cinnabar and barccnite in the gravel and mud filling the vents. A 150-ton flotation plant is in operation concentrating stope fills that assay 3.0 kg. of mercury per ton. In one open stope, which is more than one hectare in area and 60 m. high, 150,000 tons are available. Introduction The Huitzuco mercury mines are of interest because of the unusual occurrence of ore in extinct geyser vents and the presence of several rare mercury minerals. Some of the deposits have typical characteristics of the telethermal zone and there is a gradation towards typical epithermal mineralization in depth. Halse,1 Villarel1o,2 Mactear3 and Merri114 have described the geology and the early operations in the district, and Bar-cena5 and Mallet6 have described the rare mercury minerals, livingstonite and barcenite, found at Huitzuco. Location The village of Huitzuco lies in the north central part of the State of (Guerrero, Mexico, 27 km. (16.7 miles) east of Iguala, which is the largest and most important town in the area. Iguala is served by the Mexican National Railways and also by the Mexico City-Acapulco highway. The highway is surfaced from Mexico City to Iguala, a distance of 200 km. (124 miles) by road, and there is a fairly good, level, dirt road from Iguala to Huitzuco. The elevation above sea level is about 1000 m. (3280 ft.). The climate is warm and very dry except during the rainy season, from June to

Jan 1, 1941

By C. W. Vaupell

The Huitzuco mines lie in north central Guerrero, Mexico; production has been about 90,000 flasks of quicksilver since 1873. Near-surface ores fill extinct mud geysers and the deep deposits are chambered veins, stock-works in brecciated blocks, and replacements in limestone. The epigenetic minerals livingstonite, stibnite and sulphur occur in limestone, gypsum and dolomite through a developed vertical range of 260 meters. The deepest workings expose an increased amount of stibnite, which probably indicates that the lower limit of mercury mineralization is being approached. A resurgence of heat and water formed geysers over an extended area after the period of mercury mineralization. Mud geysers, which are situated, in the outcrops, contain the secondary mercury minerals, cinnabar and barccnite in the gravel and mud filling the vents. A 150-ton flotation plant is in operation concentrating stope fills that assay 3.0 kg. of mercury per ton. In one open stope, which is more than one hectare in area and 60 m. high, 150,000 tons are available. Introduction The Huitzuco mercury mines are of interest because of the unusual occurrence of ore in extinct geyser vents and the presence of several rare mercury minerals. Some of the deposits have typical characteristics of the telethermal zone and there is a gradation towards typical epithermal mineralization in depth. Halse,1 Villarel1o,2 Mactear3 and Merri114 have described the geology and the early operations in the district, and Bar-cena5 and Mallet6 have described the rare mercury minerals, livingstonite and barcenite, found at Huitzuco. Location The village of Huitzuco lies in the north central part of the State of (Guerrero, Mexico, 27 km. (16.7 miles) east of Iguala, which is the largest and most important town in the area. Iguala is served by the Mexican National Railways and also by the Mexico City-Acapulco highway. The highway is surfaced from Mexico City to Iguala, a distance of 200 km. (124 miles) by road, and there is a fairly good, level, dirt road from Iguala to Huitzuco. The elevation above sea level is about 1000 m. (3280 ft.). The climate is warm and very dry except during the rainy season, from June to

Jan 1, 1941

By T. Sterry Hunt

I have in a previous communication called the attention of the Institute to the geognostical relations of the crystalline iron ores belonging to the Eozoic racks of North America, at which time I noticed (1) those associated with the gneisses of the Laurentian series, (2) those of the crystalline schists of the Huronian, as seen in Northern Michigan and in many localities along the Appalachians; (3) those of Southeastern Missouri associated with petrosilex porphyries and schistose rocks, and presumed to be nearly of the same age with those of the Huronian schists; and (4) the highly titaniferous ores of the Norian or Labradorian series from Essex County, N. Y., and from various parts of Canada. It may here be remarked that, although the presence of titanium is most marked in the Norian ores, this objectionable element is sometimes found in the schistose ores of the Huronian, and to a lesser extent in certain Laurentian magnetites. The ores of each of these geological divisions have their individual peculiarities, which serve to distinguish them to such a degree that the magnetites and specular ores of the Laurentian are as dissimilar to those of the Huronian as are the crystalline silicated rocks of the two series. As it happens that these mineralogical dissimilarities correspond to diflerences in composition and in adaptability to different processes of manufacture, which, in the present condition of the iron industry, are objects of special consideration to metallurgists, it will be seen that these geognostical distinctions become of great practical importance. During the past year I was desired by the Geological Commissioners of Pennsylvania to devote a few weeks to certain geological studies in the eastern part of the State, in the course of which I was enabled to make, with regard to its crystalline iron ores, some observations to which I desire to call the attention of the Institute. I may mention, in passing, that the great South Mountain belt, from the Schuylkill to the Delaware, is composed of Laurentian rocks, in which are found the characteristic ores of the series like those of the Highlands of New Jersey and New York, and of the Adiron-

By R. A. Falconer, H. L. Lovell

With increasing requirements for fine coal cleaning and the many advantages of the cyclone operating on a coal-water slurry, a series of studies designed to achieve an enhanced understanding of the cyclone parameters has been pursued. The purpose of this investigation has been to vary a series of dimensional parameters with an experimental 15-in. diam hydro-cyclone, and to determine the relative effects of parameter variations upon ash and sulfur removal. This study of the hydrocyclone is a continuation of a series of investigations, conducted in the Dept. of Mineral preparation at The Pennsylvania State University, which are directed toward the removal of ash and sulfur constituents from fine bituminous coal by size-density separations in cyclones, and toward a fuller understanding of the complex mechanisms involved in such separations. The purpose of this investigation has been to vary a series of dimensional parameters with an experimental 15-in. diam hydrocyclone, and to determine the relative effects of parameter variations upon ash and sulfur removal. Of special interest was the response to cone angle variation, since it is the high included cone angle that generally distinguishes the hydrocyclone as a gravity separator rather than a classifier. DESCRIPTION OF THE HYDROCYCLONE Fig. 1 is a dimensional drawing of the hydrocyclone used in the investigation. The unit was designed and fabricated by Heyl and Patterson, Inc., for experimental use. The dimensional parameters considered were: 1) Three cone sections having included angles of 45, 60, and 95,degrees, 2) Three 3 1/8 in. diam vortex finders having lengths of 15, 17, and 19 1/2 in., 3) Three 4 1/16 in. diam vortex finders having lengths of 15, 17, and 19 1/2 in. 4) Two apex sections having diameters of 2 and 2 1/4 in. The feed inlet orifice had a fixed diameter of 3 in. The hydrocyclone test installation was made at The Pennsylvania State University pilot plant at Barnes-boro, Pa., which operated at 50 tph. During the period that the hydrocyclone was tested, research was in progress at the Barnesboro site to reprocess refuse material from a near-by coal preparation plant in

Jan 1, 1968

By E. L. Fisk

First discovered and claimed in 1929, the Cordero cinnabar deposit lies 11 road miles southwest of McDermitt, Nev., near the Nevada-Oregon boundary. The name "Cordero" means "little lamb" in the Basque language and is symbolic of the fact that the first ore specimen was found during the lambing season. The Bradley Mining Co. held the property for several years during the early thirties, but it was not until 1939 that Cordero Mining Co., a subsidiary of Sun Oil Co., entered the picture. The company, then known as Horse Heaven Mines, Inc. conducted preliminary work in 1940 which proved enough near-surface ore to warrant the construction of a mill during the following year. By 1943, Cordero was being rapidly depleted when deeper churn drilling intersected the large underground orebody that is still being mined today.

Jan 11, 1961

By Max Barber

PRESENT equipment and practices in open-pit mines of the Lake Superior iron ranges have been described recently in some detail by A. H. Hubbell.1 It is anticipated that any further improvements will be the result of gradual evolution of present methods and equipment, just as those now used have been gradually evolved from earlier methods. An exception to the process of gradual evolution during the last decade has been the adoption of electric power for operating shovels and trains in open-pit mines, but it is not expected that any such revolutionary changes will be made in the future. The use of Diesel, engine equipment will gain considerable headway, no doubt, and will find favor in certain lines of operation as improvements and adaptations are evolved to meet particular requirements. The question of installing belt conveyors for handling material from deep mines of restricted area, where haulage grades become a serious consideration, or even for transferring earth, rock, or ore material for distances of several miles, is now being studied and some very interesting data are being obtained.

Jan 1, 1932

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons. ) Position in sales department is open for a mining engineer with experience in mine ventilation and possessing some knowledge of fan design; one competent to lay out ventilating systems to meet various conditions. No. 2. A large company manufacturing mining machinery has an opening in one of its Western agencies for a young mechanical engineer who has had some experience in designing along general machine shop lines, and who is familiar with cost systems. No. 3. A large university desires to secure a prominent metallurgist for a vacant professorship in metallurgy. No. 4. Opening at a mine in New Jersey for a technical graduate to begin work as chairman on the surveying squad. Salary $50 per month to start. No. 5.

Jan 11, 1913

By R. L. Templin

IN TREATING a cast metal by any working process such as rolling, drawing or forging, variations in the conditions present in the remelting, casting, chilling and preheating of the initial ingot will certainly have some effect on the physical properties of the final product. In considering the effects of cold working on the physical properties of metals, however, it will be assumed that these factors, being controlled according to best practice, will remain constant and therefore may be neglected. Starting with such a uniform metal ingot, the next operation in the production of wrought metal involves hot working by rolling, forging or extrusion so as to produce a slab, billet or bloom. This working must be sufficient to produce substantial grain refinement and minimize any defects occurring in the initial ingot. Even such a hot-worked product is not suitable as a starting material for determining the effects of cold working because it contains internal strains analogous to those resulting from cold working. It is necessary, therefore, to supplement the hot working with a considerable amount of cold working, followed by a proper annealing in order to obtain a material suitable for use in defining the effects of cold working on the physical properties of a metal. That is, if the effects of cold working are to be evaluated accurately it is necessary to have other effects at least constant if not absent. Such material, unfortunately, cannot always be obtained in commercial practice but the requirements just indicated certainly represent the desired goal; this goal has been attained in the treatment of some metals, one being aluminum.

Jan 1, 1929