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By Robert W. Hunt

(Cleveland meeting, October, 1912.) PERHAPS of all the scientific economic questions which have been claiming the attention of capitalists, metallurgists, manu-facturers, directors of public utilities, and the general public of America, during the last few years, none have been of more importance than the one relating to the wear and safety of steel rails. The discovery of the Bessemer process made possible modern railway development. In that growth, as has generally happened in all progressive movements, ill its department have not remained equally balanced. Iron rails permitted the construction of roadways for the passage of power-driven vehicles. In time the speed and weight of such carriages proved too much for the wearing-qualities of the rails, and the limit of railway capacity seemed to have been reached. Bessemer made his invention, which was soon perfected and developed, especially as related to steel rails, and thereby increased the limit of capacity, acid vastly greater railway progress was, made possible. The Siemens-Martin open-hearth process followed, and was later supplemented by the Thomas-Gilchrist basic improvement. For a time the Bessemer steel rails of commerce Were, more than equal to all that was asked of them, but this did not long continue, as evidenced by the records in our Transactions. Revolutionary changes occurred in the industrial world, and in no part of it more than in steel-rail manufacture. Great and powerful commercial combinations were made, whose financial resources made possible the supplanting of the then most efficient blast-furnaces, steel-works, mid mills, by others of theretofore unimagined capacity. Old traditions and practices of steel-making were wiped away, and, in too many cases, output was apparently the chief aim, with the result that much dissatisfaction with the wear and safety of rails was felt by railway officials, and the general public was concerned as to its safety when traveling. The climatic conditions of the winter

Dec 1, 1912

"Butte is in many ways an ideal location for a mining school. The student lives in the atmosphere of his intended profession. By the time he has spent four years at the school and in the community he has a fairly clear idea of what kind of a business he is entering upon, and is freed from any illusions about its being a primrose path he is about to follow. The mines and mills and smelters are his lecture rooms in part, and the shovel, pick and drill form part of his equipment. Most of the students work in the mines during part of their school life, which serves the double purpose of assisting them financially and increasing their practical knowledge.The School of Mines is a state institution, amply endowed and exceptionally well equipped. The school is strictly technical and no attempt is made to prepare men for any other work but mining engineering. The mining men of the community take an active interest in the welfare of the school and are of much assistance in securing employment for its graduates.The teaching staff is entirely composed of men who have had practical, commercial experience in their various specialties, and no expense is spared in securing suitable men for the faculty."

Jan 1, 1913

By Worthen Bradley

A BETTER understanding of what is happening in the domestic quicksilver industry, and what is likely to happen, can be had after reviewing some of the highlights of the past four years. Hitting the high spots in chronological order, they are: February 1939-Army and Navy Munitions Board starts investigation on civilian and war needs of certain "strategic materials," including quicksilver, with a view to recommending stock piles. Every known producer is canvassed by the end of the year.

Jan 1, 1942

By J. A. Bownocker

THE EXISTENCE of petroleum in the rocks of Ohio and Indiana seems to have been first shown by wells dug for salt. The fuel, however, was objectionable owing to its odor and inflammability. Not until the brake well was drilled in 1859 did the people appreciate the value of rock oil, and then they at once began plans to secure the coveted fuel.. The first successful well in these two states was near . Macksburg, in southeast .Ohio, where at a depth of 59 ft. (17 m.) :oil was found in commercial quantity (1860). A year later this fuel was secured on Cow Run, in the same county, and at about the same time in Noble, Morgan and perhaps other counties in that part of Ohio. The second great step in the production of oil in Ohio and Indiana was taken in 1884 when the reservoir of natural gas in the Trenton limestone of northwest Ohio was tapped, and where a year later oil was secured in the same formation. Petroleum in this limestone was obtained in Indiana in 1889.1 The third step in the production of oil' in Ohio and Indiana is associated with the Clinton sand of Ohio. Natural gas in large volume was discovered in that rock at Lancaster, in 1887, and the area has been extended until it has become the largest individual producer in the world. The presence of natural gas in such great volume all but demonstrated to the driller that-oil lay hidden near by. Soon the search for it was started but not until 1899 was petroleum in commercial quantity found in the Clinton sand, and a large pool was not located in it until 1907. The fourth step in the development of the industry was taken in 1913, when the pool in Sullivan County, in western Indiana, was opened. The producing rock is the Huron sandstone, which is the topmost member of the Mississippian system.2

Jan 2, 1920

By Noel Jarrett, Allen S. Russell, Bernard M. Starner, Stanley C. Jacobs

A process has been developed to refine high-grade commercial aluminum to 99.99 pct purity. This enzploys precipitating titanium, vanadium, and zirconiu~ as borides. The upgraded liquid is partially crystallized under conditions that prevent massive freezing. The resulting crystals are compacted and washed free of adhernig impure liquid aluminum by melting the top crystals while draining off the liquid. Finally, the bottorn portion of the crystal bed is melted and removed as the pure product. Leakage from the crystallizat~on vessel is prevented by a layer of alumina granules that are not wetted by the aluminum. ALUMINUM of 99.99 pct purity is desired in a variety of applications. These include electrolytic capacitors, catalyst carriers, decorative trim for automobiles, aluminum powder, and high-strength alloys. This market was for many years filled by refining commercial-purity aluminum in a three-liquid-layer electrolytic cell of the type originally proposed by Hoopes. To meet the expanding need for lower-cost high-purity aluminum, a refining process based on chemical precipitation and fractional crystallization was developed. The availability of this super-purity metal was announced in November 1961, and three patents1-3 relating to the process were issued in 1965. An alternate process, comprising continuous fractional crystallization of a portion of a liquid-aluminum feed stream under conditions of strong agitation at the surface of the growing crystals, was published by Dewey4 in 1965. Earlier proposals by Larsen 5 and by Regner6 also emphasized the advantage of rapid agitation of the melt in the region of the crystallization zone. johnson 7 more recently proposed extracting purified aluminum from an alloy by mixing crystals of pure aluminum into the molten alloy, allowing them to grow, and removing the pure aluminum as by casting. Aamot's 8 recent patent describes a freeze refining process that involves controlled partial freezing against cooled moving retort walls. The Alcoa process to produce high-purity aluminum is schematically described in Fig. 1. Relatively pure aluminum is treated with boron in a furnace (a) to precipitate high melting point impurities, the supernatant liquid is transferred to a crystallization vessel (b), the liquid is partially crystallized with mechanized "tamping" (c), the remaining impure liquid is tapped out and the crystal bed partially and directionally re-melted to wash the underlying crystals (d), and the balance of the crystals is melted and withdrawn as high-purity aluminum (e). PRINCIPLES OF FRACTIONAL CRYSTALLIZATION Commonly encountered impurity elements form two types of systems with aluminum. Titanium, vanadium, and some other transition elements in periodic groups IV, V, and VI are the high melting point impurities. Initial solidification of aluminum containing small percentages of these elements will produce solid markedly enriched in them at temperatures slightly above the freezing point of high-purity aluminum. Most other elements, such as silicon and iron, produce eutectic type reactions with aluminum. In this case the first solid formed on initial solidification at temperatures slightly below the freezing point for high-purity aluminum is markedly depleted while the remaining liquid is enriched in these elements. The equilibrium change in composition during solidification of aluminum contaminated with silicon, iron, or titanium is illustrated in Fig. 2. Here, for clarity, the temperature scale is expanded beyond the

Jan 1, 1968

By David B. Reger

New discoveries of gas in the southern counties featured the petroleum industry in West Virginia during 194;. Drilling for oil increased slightly over 1944 and a small increase of initial production resulted. Out of 28 wildcats drilled, there were 16 gas discoveries and 12 dry holes. No commercial oil was found in the 28 wells.

Jan 1, 1946

Louis D. MILLS, San Francisco, Cal. (written discussion *).-The principle involved in the Crowe vacuum precipitation process is so elementary and the apparatus required is so simple, that the whole subject affords scant material for a technical discussion. As. one prominent Colorado metallurgist recently remarked when asked to contribute to this paper: "The Crowe process is the biggest step forward since the early clays of the cyanide process, but there is nothing to write about; just put it in your mill and try it." The writer confesses to a similar feeling, but having been closely identified with the process since its inception in 1916, he is perhaps in a position to at least comment on the theory involved and to record some of the results that have been achieved in actual practise. In practising the Crowe process, the solutions to be precipitated are first vacuumized in a suitable dispersion tower; that is, thin films of the liquid are subject to the action of a vacuum within a receiver. Sub-

Jan 1, 1919

By J. A. Bownocker

The existence of petroleum in the rocks of Ohio and Indiana seems to have been first shown by wells dug for salt. The fuel, however, was objectionable owing to its odor and inflammability. Not until the Drake well was drilled in 1859 did the people appreciate the value of rock oil, and then they at once began plans to secure the coveted fuel. The first successful well in these two states was near Macksburg, in southeast Ohio, where at a depth of 59 ft. (17 m.) oil was found in commercial quantity (1860). A year later this fuel was secured on Cow Run, in the same county, and at about the same time in Noble, Morgan and perhaps other counties in that part of Ohio. The second great step in the production of oil in Ohio and Indiana was taken in 1884 when the reservoir of natural gas in the Trenton limestone of northwest Ohio was tapped, and where a year later oil was secured in the same formation. Petroleum in this limestone was obtained in Indiana in 1889.' The third step in the production of oil in Ohio and Indiana is associated with the Clinton sand of Ohio. Natural gas in large volume was discovered in that rock at Lancaster, in 1887, and the area has been extended until it has become the largest individual producer in the world. The presence of natural gas in such great volume all but demonstrated to the driller that oil lay hidden near by. Soon the search for it was started but not until 1899 was petroleum in commercial quantity found in the Clinton sand, and a large pool was not located in it until 1907. The fourth step in the developrllrnt of the industry was taken in 1913, when the pool in Sullivan County, in western Indiana, was opened. The producing rock is the Huron sandstone, which is the topmost member of the Mississippian system.²

Jan 1, 1921

By K. J. Brondyke, P. D. Hess

Two processes have been developed for improving the quality of molten-aluminum alloys before casting. The Filtration Process. which involves passing molten metal through a packed bed of granular filter material, is a rapid means of removing finely divided particles. It has the most potential in those instances where removal of inclusions is of primary importance. The Combination Fillration-Inert Gas Fluxing Process inuolzles introduction of an inert gas so that it will diffuse countercurrent to metal flow through the filter bed of granular material. Dissolved hydrogen is removed from the metal in addition to removal of finely divided particles. The Combination Process is most useful where both inclusion removal and attainment of conistently low-hydrogen-content metal are important. Metal treated by the Combination Process is of higher and more uniform quality than heretofore attainable with prolonged chlorine fluxing. Costs of the Combination Process can, for the most part, be offset by savings derived from high recoveries and increased production of superior-quality products. IMPROVEMENT in the quality of molten-aluminum alloys is secured generally through the use of some fluxing practice in a crucible, holding furnace, or ladle involving either gaseous or solid fluxing media. Typical fluxing agents may include the gases nitrogen, argon, or chlorine used either singly or as mixtures and the solids aluminum chloride or hexachloroethane. Regardless of the fluxing means used, the primary objectives are the adequate removal of both metallic and nonmetallic inclusions and reduction of hydrogen content to an acceptably low level. The ultimate goal is to produce ingots and cast products of high quality free from inclusions and porosity. The development of ultrasonics for measurement of internal quality, tightening of quality controls, and the application of the aluminum alloys to new or different commercial fields have been responsible for an ever increasing demand for improvement of quality of both cast and fabricated products. This demand for high quality has not been restricted to any single type of product. On the contrary, the demand encompasses about the entire variety of products including those for fabrication, those to be machined, buffed, or finished for decorative purposes, and those for critical applications where both surface and internal quality is of utmost importance. In many instances products acceptable in the 40's would now be scrapped as unacceptable by these higher present-day standards. With this ever increasing demand for higher quality, it became apparent at Alcoa that conventional means of melt treatment were inadequate in many instances and new approaches were necessary. Consequently the research program was intensified with attention focused on metal treatment during transfer in order to reduce the furnace processing time to a minimum in an effort to attain the desired results at a minimum of additional expense. As a result of this intensive research program which covered numerous variations and adaptations of conventional methods in addition to new methods of melt treatment, several new processes were developed, two of which will be described here. The first of these, a method of melt filtration, was patented in February, 1959.l The second process involving combination filtration—inert gas fluxing was patented in June, 1962. 2 Other melt-treatment processes developed during this period of investigation were patented as listed.3 FILTRATION PROCESS General Description. The Filtration Process, which involves passing molten metal through a packed bed of granular filter material, is a rapid method of effectively removing finely divided particles. It is an impingement-type filter; hence the size of the particles removed from the metal are considerably smaller than the interstices of the

Jan 1, 1964

By P. Raffinot, M. Rey, V. Formanek, G. Sitia

Six years of laboratory study, followed by three years of mill operation treating more than 10,000 tons of ore, have established the flotation of oxidized zinc ores with fatty amines as an efficient process. Recently the method has been applied with success to partially oxidized sulphide ores. In this paper the authors give an account of their research and the milling results obtained in Sardinia since 1951. CONCENTRATION of oxidized copper and lead ores by flotation has been practiced for 30 years, but flotation of oxidized zinc ores has remained unsolved until a few years ago. This problem is, however, of great importance in mining districts where large tonnages of oxidized zinc ores exist in underground mines or in dumps. Some sulphide ores also possess a degree of oxidation high enough to justify recovery of oxide zinc minerals. Various attempts have been made to float the zinc carbonate, smithsonite. It is well known' that smithsonite can be collected with fatty acids, but as the predominant gangue constituents, limestone and dolomite. are floatable with the same reagents, fatty acids are difficult to use. Gaudin has shown,' on mixture of pure minerals, that smithsonite can be floated with higher xanthates, or better, with higher mercaptans. Another procedure, briefly mentioned by Davis," consists in sulphidizing the ore, activating the zinc carbonate with copper sulphate, and floating with ordinary xanthates. This process was attempted in the writers' laboratory in 1946, but results were erratic. It has since been taken up by Italian engineers and is in operation on certain types of ores. Two other research projects should be mentioned. In 1942 Erlenmeyer and others' floated synthetic mixtures of smithsonite and gangue minerals with hydroxyquinoline, an analytical reagent for zinc. On the other hand, Bunge, Fine, and Legsdin published in 19465 Some interesting results obtained on Missouri oxidized zinc ores. With sodium oleate as a collector and a combination of sodium hydroxide, sodium silicate, and citric acid as a limestone depressor, they secured, after four cleaning operations, a good grade of concentrate. With many ores this reagent combination lacks adequate selectivity. In 1939 M. Rey initiated a program of research on this important problem. Work was pursued first at the School of Mines in Liége, Belgium"' and later in Paris in the laboratories of Société Miniére et Mbtallurgique de Penarroya and Société Minerais et Métaux. Reagents used in the beginning were higher xanthates and mercaptans, later fatty amines. Sulphidization with sodium sulphide was found necessary. These conditions make possible the flotation of zinc carbonate and zinc silicate. Two milling plants were put in operation in Sardinia in 1950 and several others are now contemplated." ' It should be mentioned that unknown to the present writers McKenna, Lessels, and Peterson were

Jan 1, 1955

Thomas T. Read, New york, N. Y. (communication to the Secretary *):—At the meetings of English technical societies it not infrequently happens that, during the discussion of a paper, someone will arise to say that although he highly appreciated the material presented, nevertheless he believed it would have been better if some other phase of the question had been more highly emphasized. Assuming that this form of discussion is permissible in the Institute, I should like to reiterate the point made by Prof. A. J. Moses that conclusive proof of the identity of the minerals in question is an essential feature of the study of ores in this way. This is also expressed by Paul Krusch in his recent valuable paper on the sulphide ores (in which he arrives at conclusions diametrically opposed to those of Mr. Graton), as follows: "The diagnostic properties of the various ore minerals are known to but a limited circle of investigators." Many earlier investigators began the study of ores beneath the microscope by reflected light, but discontinued their work, in most cases, because they were unwilling to undertake the great amount of preliminary work necessary to securely establish a basis for their inferences. It is evident that Messrs. Graton and Murdoch realize that the promised later paper on diagnostic characters will be the more important of the two, but the point should be emphasized to forestall a flood of literature from other investigators who may gain the impression that the brief survey of polished specimens is a vade mecum to incontrovertible conclusions as to any given ore deposit.

Jan 1, 1914

Boiler-Room Economy "Establishing and Maintaining Boiler-room Economy" is the title of a paper presented before the Ohio Society of Mechanical Electrical and Steam Engineers by Geo. H. Gibson, of which the following is an excerpt: Boiler-room economy depends less upon equipment than upon operation, i.e., it depends largely upon the condition in which the apparatus is maintained and how it is used. A given boiler may operate this week with an efficiency of 78 per cent., and next week with an efficiency of 65 per cent., while using the same fuel and developing the same rating. If there are variations ii; character of fuel and in load and other factors, the falling-off may be even greater, possibly to less than 60 per cent. The steam produced may cost twice as much per 1,000 lb. at one time as at another. Most steam plant managers know from their own experience that these statements are not exaggerated. It does not take much of a plant to run up a coal bill of $5,000 per year, many "spend $10,000 for coal, and fuel bills of $50,000, $100,000, or $200,000 per annum are not uncommon. As it call be shown in the majority of these plants that 10 per cent. of this amount may be saved, and in large numbers of them 25 per cent., while in some the expenditure can be cut in half, there is no disputing that we have here a subject worthy of attention. In the production of steam the greatest variable is the human factor. Before we can pass judgment, however, we must first have standards. This implies accurate quantitative knowledge of fuel consumption and steam production. We must measure the output and know how much the steam costs per thousand pounds, and how many pounds of steam are obtained from a pound of coal. We can then begin to analyze the problem, and find where and how methods and conditions can be improved, and how much. Many favor buying coal on a B. t. u. basis. This is advisable where the amount purchased warrants the considerable expense involved in systematically gathering samples that: are. truly representative and in having analyses made, of every carload. Coal analyses, combined with. an honest endeavor on the part of the miner to ship good coal, should insure the receipt of the heat units paid for. , It often happens, however, that the coal which is cheapest on a B.t.u. basis is not the cheapest or most suitable for producing steam, because of peculiarities of the plant in which it is to be burned, or conversely, the fuel which furnishes cheap B.t.u. may require special methods or equipment for its economic utilization.

Jan 2, 1916

By Albert Sauveur

(Cleveland Meeting, October, 1912.) ALTHOUGH many metallurgists know that some pearlitic special steels can be made troostitic, martensitic, and even austenitic, without quenching, and, therefore, without exposing them to the dangers of the quenching-bath, the practical significance of such possibility does not seem to have received the attention it deserves. Let us recall briefly the mechanism of the transformation alluded to. In Fig. 1 (after Guillet) is shown the constitutional diagram of nickel-steel that; is, of alloys of iron, carbon, and nickel. Any steel the composition of which falls within the area LPO is pearlitic after slow cooling; any steel the composition of which is represented by a point within the area MLO is martensitic, and any steel within the area MNO is austenitic. Starting with pearlitic steel, then by increasing the carbon-content or the nickel-content, or both, the metal becomes martensitic and eventually austenitic; that is, its composition crosses first the boundary-line LO and then the line M0-and it remains martensitic or austenitic after slow (air) cooling.1 We have inn this way imparted to the metal without quenching it the properties of hardened carbon-steel. In other words, the steel is now self-hardening. Nickel cannot be introduced into solid steel, but by the well-known process of case-hardening it * Professor of Metallurgy and Metalllography in Harvard University. + Assistant in Metallurgy and Metallography in Harvard University. 1 The boundaries between the various zones are not, as a matter of fact, as sharp as indicated in the diagram, because pearlite is not transformed abruptly and in its entirety into martensite when a certain critical composition is attained, nor is martensite suddenly and completely converted into austenite. Greater refinement in the construction of the diagram would undoubtedly result in the introduction of troosto-pearlitic, troostitic, and troosto-martensitic zones between the pearlitic and martensitic areas and-of a martenso-austenitic zone between the martensitic and austenitic areas. Fur the purpose of this note, however, the existence of these transition-conditions may be ignored.

Nov 1, 1912

By W. J. Schuster

Safety in coal mines depends largely upon adequate training of the foreman. Although management must provide modern and safe equipment and at all times keep mines in first class condition from a safety viewpoint, final results will be determined by the quality of supervision. HANNA COAL CO., Division of Pittsburgh Consolidation Coal Co., operates three large underground mines in eastern Ohio. The section of Pittsburgh No. 8 coal seam in which these mines are located varies in thickness from 52 to 64 in. It is immediately overlain by a stratum of shaly material 12 to 15 in. thick locally known as draw slate, which is structurally very weak and which disintegrates rapidly upon exposure to atmosphere. Immediately above the draw slate as it is normally found is a band of extremely high ash material 6 to 12 in. thick known as roof coal or rooster coal, and above this is a stratum of conglomerate material varying from 4 to 10 ft in depth. Overlying the conglomerate is a relatively thick stratum of limestone, the first stable material above the Pittsburgh coal seam in eastern Ohio. With the method of full-seam mining that has been adopted, draw slate is shot down, loaded with the coal, and removed in the preparation plants. The roof coal then becomes the permanent roof. The major problem in mining the No. 8 seam in eastern Ohio is control of the roof. Since the strata above the draw slate contains no material with a structure firm enough to provide self-support, the roof begins to sag in a relatively short time after the coal and draw slate have been removed. The problem thus becomes one of getting temporary safety posts under this roof as quickly as possible to prevent a break or separation from occurring either in the roof coal or in the conglomerate above it. Haulage System The Pittsburgh No. 8 seam in eastern Ohio is relatively level, with only minor local dips. Throughout the Hanna Coal Co. mines, entries are generally 12 ft wide. Rooms are driven on a 60" angle on 30-ft centers and are 22 ft wide. No attempt is made to extract the 8-ft pillars between. The entire length of main line haulage is gunited in one mine, and a major portion in another. Two of the mines have single-track main haulage roads with passways. The third, a new mine, is double-tracked, and the roof is supported by steel crossbars, 60 lb or heavier, spaced on 4-ft centers and lagged. In recent years timbering on main line and secondary haulage roads has been accomplished by one of two methods: 1—crossbars are supported on a small section of post set in a hitch hole in the rib, or 2—or a hole is drilled in the rib about 12 in. below the roof, of sufficient depth to fasten securely a short length of 40-lb rail, the bottom of the rail facing the roof, on which a short post is set directly under the crossbar. At present the hitch-hole timbering method is favored. At two of the mines the main line haulage locomotives are 26-ton, 8-wheel units. These locomotives are of the axleless type, each wheel being individually mounted on the frame. The motorman's compartment is encircled by 3-in. armor plate for the protection of the occupants. At the third underground mine conventional 15-ton locomotives are being used. However, these locomotives have been completely rebuilt in the company's shops. Equipment has been streamlined and quarters have been provided for two people, who are protected by heavy steel plate in much the same way described above. This modernization program has been completed on all secondary haulage locomotives at the three mines, and the company is well on the way to similar equipment of the 6-ton section locomotives. The following additional features have been included in their modernization: 1—additional support for the motors to prevent their falling to the middle of the track and derailing the locomotives should a break occur in the suspension bar support; 2—installation of additional bracing to prevent brake rigging from becoming displaced and causing derailments; 3—enclosure of all electric wiring in conduit or raceway; 4—provision of an enclosed compartment for the storage of re-railers, jacks, and other equipment, so that they need not be carried on the outside of the motor; and 5—redesign of the end of the locomotive opposite the operator's compartment to prevent anyone's mounting from that direction. It is interesting to note that some

Jan 1, 1955

By Ralph W. Marsden

The natural iron ores of the Lake Superior Region in the United States are being replaced by iron-ore concentrates produced from magnetite- or hematite-rich horizons in the Precambrian cherty iron formations. The production of natural ores will soon be less than one-half of the total ore shipped annually. The tonnage of natural ore produced will continue to decline until it is a minor percentage of the ore shipped. The natural ores include (1) soft ore, (2) hard ore, ( 3) conglomerate ore and ( 4) siliceous ore. The soft ores are the important ore type and are sometimes termed "Lake Superior type ore". These ores are in situ deposits of hematite and limonite formed by the leaching of silica and other gangue materials in the iron formations. The leaching is believed to have been done by downward moving surface waters. In deep ore deposits, generally over 1000 feet below the present surface, circulation and leaching action may have been assisted by hydrothermal activity. Hard ore deposits occur on the Vermilion and Marquette ranges where hematite or magnetite has replaced the silica (and possibly some silicates) in cherty iron formation. These ores commonly occur in structural situations favorable for the movement of hydrothermal waters. The ores are believed to be the result of hydrothermal action with iron, possibly from the iron formation, transported by hydrothermal waters to areas favorable for the replacement of silica by iron oxides. Certain stratigraphic horizons of the Lake Superior Precambrian cherty iron formations contain sufficient iron as magnetite or hematite, with a grain size and texture that will give adequate mineral liberation, to yield an ore-quality product after grinding and concentration. The magnetite-rich deposits are termed magnetite taconites. These ores occur on the Mesabi, Gogebic, and Marquette ranges. Magnetite taconite ores are unenriched cherty iron formation and are the result of the sedimentary deposition of the iron formation and the metamorphic history of the rock. The commercial quality hematite-rich iron formations in Michigan are termed jasper ores. The jasper ores are being mined on the Marquette and Menominee ranges. These ores are composed of specular or granular hematite associated with quartz and iron silicates. The jasper ores appear to be recrystallized iron formations in which iron, prior to recrystallization, occurred as hematite.

Jan 1, 1968

By John L. Ham, Robert M. Parke

THE melting point of molybdenum is 2625° ± 50°C. Heretofore the metal has been considered too refractory to be melted in commercial quantities; hence, it has been formed into rod, wire, and sheet by the methods of powder metallurgy, wherein the temperatures do not exceed 90 per cent of the melting temperature. The manipulation of liquid metals at temperatures of about 2000°C. and above presents some difficult problems in heat transfer, in purification, and in container materials. For metals melting at such high temperatures, it is generally regarded as expedient to circumvent the more common melting and casting process by resorting to powder metallurgy. This circumvention is not accomplished without some penalties, the more notable of which are the relatively high cost of the powder metallurgy method and particularly the size limitations of its product. In an effort to overcome the inherent disadvantages of the powder metallurgy method, especially in respect to the limit of size, a project was begun in 1943 at the Climax Molybdenum Co. laboratory to develop a method of melting and casting molybdenum capable of producing larger bodies of molybdenum than were then obtainable. Later, from Feb. 1, 1944, to Aug. 31, 1945, the project was under the supervision of the National Defense Research Committee, Division One. In peacetime, too, there are needs for molybdenum, which make consideration of another process desirable; for example, large parts for heat engines generally, the omnipresent demand for metal of higher quality and lower cost, and the development of molybdenum-base alloys. This paper describes methods for melting and casting molybdenum, with details of the special process needed to make molybdenum castings ductile, and reports some of the properties of what may be regarded as a new, or at least modified, form of the metal. FIRST PROCESS FOR MELTING AND CASTING MOLYBDENUM The maintenance of a temperature greater than 2625°C. in a space large enough to melt several pounds of molybdenum may involve the loss of heat at a very considerable rate. For melting molybdenum, therefore, the source of heat must be of high potential and of fairly high power. Evidently, also, the source of heat must not impair the purity of the product. The electric arc operating in vacuum appeared to meet these requirements and was accordingly the first choice as a source of energy. A number of arc devices for melting molybdenum were examined, and several were tried. In the first experiment, a 20-kw., 60-cycle-per-second alternating-current arc was operated between two horizontal and opposed electrodes of molybdenum. In this arrangement the falling droplets of molybdenum solidified below the arc in an irregular mass. This experiment did not produce a useful casting, but the data obtained indicated that

Jan 1, 1946

By W. D. MOTTER

THE following brief description of the status of operations of the Chile Exploration Co. at Chuquicamata, Chile; and of the plant as it exists today, points out the-great progress that has been made since the initiation of prospect drilling in 1912. During the 11 years which have elapsed since then, a group of small mines, eking out a 'precarious existence, has been consolidated into one large operating property,, taking high rank among the world's producers of copper. After a drilling campaign followed by a construction period, the plant first started operations in 1915. Since then production has been gradually increased, as world conditions permitted, until the present status has been reached.

Jan 1, 1924

By Benjamin B. Lawrence

The lease-system is the gradual result of the development of our larger producing mines throughout the State of Colorado. The operation of a mine, or group of mines, by corporations has been attended, in many cases, by disaster, owing to the difficulty of securing a fair day's work from the men employed in the mine, and the loss entailed by careless mining and sorting of high-grade ores, or by lax or inefficient management on the part of superintendents and foremen. Given, therefore, a mine that has been practically abandoned by its owner, for the reasons given, but still possessing merit, the lessee appears on the ground and secures a lease for a year, or term of years, from the owner, upon the payment of a royalty upon the gross smelter- or mill-returns of the ore which he mines. In this way many of our abandoned mines have been re-opened by the miner, who, with two or more associates, has been enabled, by careful attention, to obtain profitable results.

Jan 1, 1893

Under date of Sept. 30, the following open letter was addressed to the Members of the Colorado Section of the American Institute of Min-ing and Metallurgical Engineers by a Colorado Committee: At a meeting of the Colorado Section of the American Institute of Mining and Metallurgical Engineers, held on Friday, Sept. 19, a reso-lution was unanimously passed condemning the Engineers' Licensing Bill passed at the last session of the State Legislature, and requesting the Chairman to appoint a Committee to act in conjunction with the other National Engineering Societies and the Colorado Metal Mining Associa-tion, with a view to securing its repeal at the extra session of the Legis-lature which the Governor has expressed his intention of calling. It may be within your knowledge that the bill in question was passed by the Legislature and signed by the Governor without the knowledge of any of the National Societies, and of few if any of their members. Under its provisions residents of other states cannot even come into this to examine a mine without securing a license, and aliens (among whom are many honored members of, the profession in Colorado) cannot obtain such a license at all. The mining industry in this state needs the coopera-tion of outside engineers, and we should welcome any assistance from them that will tend to develop our resources. To attempt to discourage the activity of visiting engineers will inevitably react on us, and brand the state as being hostile to brains and capital from outside. The difficulty of securing a license will prove a serious handicap to young engineers starting out in the independent practice of their profession. Moreover, a license issued to au engineer qualified in one branch will entitle him to practice in any other: so that the license is apt to mislead the public.

Jan 11, 1919

By A. Ross Rornmel

ABILITY to speak effectively is one of man's most longed for and coveted abilities. It is the ability to stand on one's feet, transfer knowledge and thoughts to others, to reach an objective professionally or otherwise by leading groups through a channel of planned thought. Each day group speaking plays an important part in making or marring success, and the engineering profession often provides this opportunity and requirement. An ability to speak effectively develops courage, poise, confidence, and prestige for the speaker. The technical man cannot be reluctant to face an audience. He is often called upon to do this in presence of employees, supervisors, and other groups. His ability to speak effectively is as much a requirement as the fundamentals of his profession. The three fundamentals of effective speaking are: (1) Enthusiasm and Confidence. These are joined because of their close relation. (2) Preparation. This includes knowledge of the subject. (3) Presentation. By this is meant the features of delivery.

Jan 1, 1946