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By Ta M. Li

The implementation of the Clean Air Act (CAA) Amendments of 1970 has resulted in a clean fuels deficit that has significant adverse environmental, energy and economic implications, according to the Project Independence Report. The CAA Amendments charge the Environmental Protection Agency (EPA) to establish national air quality standards as well as national standards for significant new pollution sources and for all facilities emitting hazardous substance. Section 110 of the CAA provides the framework for states to establish "emission limitations, schedules, and timetables for compliance with such limitations, and such other measures as may be necessary to insure attainment and maintenance" of ambient air quality standards. State implementation plans (SIP) are subject to EPA approval. EPA is authorized to enforce federal and state requirements by order or civil suit, including injunctive relief.

Jan 5, 1975

By B. M. Andreas

PRIOR to 1934 all haulage of ore and stripping on the Mesabi Range was by rail. Early rail systems had small narrow-gage locomotives with correspondingly small dump cars. These trains were replaced with larger standard gage rail systems powered by steam locomotives ranging up to 224 tons in weight, which have in turn been replaced by diesel electric locomotives. Along with this development cars have been increased to 30-cu yd capacity. Improvement of cars includes alloy steel construction for lower over-all weight and use of roller bearings to decrease rolling resistance. Despite all of these developments, the total material hauled by rail on the Mesabi Range has decreased every year. Yet, this is no reason to believe that rail haulage is becoming obsolete. Its adaptation to small mine operation has become impractical, but in large mines where normal railroad grades are possible or where hauls to plants or dumps are long, rail haulage is still one of the most economical methods of transporting large quantities of material.

Jan 1, 1954

By A. Taylor

IN a previous communication,l the quaternary system Ni-Cr-Ti-A1 was described in detail and it was shown how certain alloys used for high-temperature applications could be construed as consisting of Ni,Cr suitably modified by the addition of aluminum and titanium in relatively small amounts. With the correct aging treatment, the ordered face-centered-cubic Berthollide phase, y'-Ni,Al, could be precipitated from the face-centered-cubic primary y-solid solution. By increasing the proportion of titanium with respect to aluminum, it was also possible to precipitate the very brittle hexagonal-close-packed Daltonide phase, ?-Ni,Ti. From the nature of the system it seems reasonable to expect the y and y'-phases to take appreciable amounts of cobalt and iron into solid solution. In the case of the present investigation it was decided to confine the work to iron additions only. This element may be introduced in two quite distinct ways: 1) as a simple replacement for nickel; and 2) as a replacement for chromium, titanium, and aluminum. The second method of iron addition forms the basis of the present investigation, which is, in effect, a study of the pseudo-quaternary system Ni,Cr-NiPe-Ni,Ti-NLAl. For purposes of reference, Figs. 1, 2, and 3 have been included and illustrate the quaternary system Ni-Cr-Ti-A1 described in the previous paper along with sections through N&Cr-Ni,Ti-Ni,Al at 750" and 1000 "C respectively. As will be shown below, the pseudo-quaternary system with components Ni,Cr, NiPe, Ni,Ti, Nihl is remarkably similar in many ways to the face defined by Ni,Cr-Ni,Ti-Ni,Al because of iron re-

Jan 1, 1958

By A. N. Mitinsky

(San Francisco Meeting, September, 1915) THE theory of elasticity, the science of the strength of materials, and all our calculations regarding engineering structures are based on Hooke's law, that in loaded bodies the deformations are, proportional to the load producing them. Without this law it would be impossible to design intelligently engineering structures such as bridges, frames, axles, etc. This being the case, the proportional limit,1 that is, the point at which deformation ceases to be proportional to load, is the most important factor in engineering design. Further, the working fiber stress should be fixed in reference to the proportional limit instead of, as is usual, in reference to the ultimate strength. The incorrect use of the ultimate strength instead of the proportional limit in setting the working fiber stress is probably clue to two reasons: (1) it is a more delicate operation to measure the proportional limit; (2) it is usually -assumed, though incorrectly, that the proportional limit is determined by the ultimate -strength. In Germany the point at which permanent set first appears is often taken instead of the proportional limit. The two points will coincide if Gerstner's law, that elastic deformations are proportional to the loads producing them both before and after permanent set, is true; and the limit of proportionality and the elastic limit or point of permanent set will both 'be represented on a stress-strain diagram, by the point at which the line ceases to be a straight line and becomes curved-or changes its inclination. It is to be further noted that the difference in definition between proportional limit and elastic limit introduces a difference in methods of determination in the testing laboratory. The German method of determining. the elastic limit by alternately loading and unloading

Jan 8, 1915

By E. M. MacKevett

The only source of uranium ore in Alaska that has been mined commercially is the Ross-Adams deposit, a gently inclined, fusiform orebody in alkali granite in which uranothorite and uranoan thoria-nit? ale the chief ore minerals. In mode of occurrence, apparent genetic association with the granite, and to a lesser extent in mineralogy, this type of deposit is uncommon. The mine is in the southern part of Prince of Wales Island (Fig. 1) at an altitude of about 950 ft on the southeast flank of Bokan Mountain. A steep unpaved road 1 3/4 miles long leads to the dock on the West Arm of Kendrick Bay, which can be reached by boat or seaplane from Ketchikan, some 35 miles to the northeast. The southern section of Prince of Wales Island is covered by dense forests interspersed with swampy tracts of muskeg. Most of the higher peaks support only sparse vegetation, and in areas underlain by alkali granite bare rocky slopes prevail to as low as 800 ft. Numerous fiord-like embayments penetrate this part of the island, and their shorelines provide near-continuous rock exposures. Rainfall is heavy, about 150 in. annually. Throughout the year the climate is relatively mild. History and Production: In May 1955 two members of a Ketchikan prospecting group, Don Ross and his wife, found the deposit while working with an airborne geiger counter. Later they confirmed their discovery by ground investigations. During the summer Climax Molybdenum acquired controlling interest in the property and started exploratory diamond drilling, resuming the drilling on a larger scale in the summer and fall of 1956. Climax began mining in July 1957, shipping the ore by barge and train to the Dawn Mining Co. mill at Ford, Wash. The open pit workings, about 370 ft long, between 25 and 75 ft wide. and 25 ft deep (shown in Fig. 2) were shut down in October 1957. As of September 1958 the pit was still inactive, although a small tonnage of known reserves remains in the southern part. The operators believe the 15,000 tons of uranium ore already produced will average 0.80 pct. GEOLOGY The Ross-Adams mine is within a small stock or boss of alkali granite, about 1000 ft from the southeast margin of the granite (Fig. 3). The area around the boss is underlain chiefly by plutonic rocks of intermediate composition and by metamorphosed sedimentary and volcanic rocks. The oldest rocks in the area probably are the metamorphosed volcanic rocks that are well exposed adjacent to the South Arm of Moira Sound. They are considered by Buddington and Chapin1 to be of Devonian age. These light gray to dark gray rocks mainly represent a layered volcanic sequence. They are commonly porphyritic with plagioclase pheno-crysts in an altered, fine-grained groundmass. The

Jan 1, 1960

By V. Koump, R. H. Tien

An approximate mathematical solution is found for the problem of unidimensional solidification of a slab of a binary alloy with time-dependent surface temperature. For the model considered, the solid skin does not form until the liquidus front has moved a certain distance. This distance depends on the rate of cooling and can be as large as half the thickness of the slab when the cooling rate is small. Assuming that the THE process of unidirectional solidification of binary alloys with constant surface temperature was analyzed by the present authors in a recent paper.' In the previous analyses, the surface temperature was considered to be lowered instantaneously, at the beginning of solidification, from its initial value to some surface temperature decreases linearly with time and that the solidus and the liquidus lines are straight, calculations are made of the temperature and concentration distributions, movements of the liquidus and the solidus fronts, as well as changes of temperature, solid fraction, and solute concentration of the liquid at the center of the slab. arbitrary temperature, lower than the solidus temperature. Although the solution of the problem for the case of constant surface temperature has some practical applications, instantaneous changes of temperature are physically impossible. Present theoretical study of the unidirectional solidification of a binary alloy is based on a more realistic model, i.e., in this case, the surface temperature of the slab decreases from its initial value continuously with solidification time. The model of solidification within the solid-liquid region is the same as the one described in the

Jan 1, 1969

By Eugene Guccione

FOREWORD-At the SME-AIME meeting in Las Vegas this year, the SME Publications Board and the MINING ENGINEERING Committee decided that a fitting way of celebrating the United States' bicentennial would be to publish an article in ME covering the great men in American mining. After some discussion as to the inclusion of financiers -men such as William Randolph Hearst, J. Pierpont Morgan, etc.-the group agreed that the feature should be restricted to the "nuts-and-bolt people," e.g., mining engineers, geologists, mineral processing engineers. Thus, from the AIME All Institute Honors roll and from the SME Awards list, the group chose these 11 historical figures: Herbert Hoover, Daniel C. Jackling, Henry Krumb, James Douglas, Rossiter W. Raymond, Hal W. Hardinge, Seeley W. Mudd, Erskine Ramsay, Howard N. Eavenson, Robert A. Richards, Arthur F. Taggart. What follows is an account of each of these great miners' achievements and the problems they faced, and an assessment by some of today's mining leaders of the challenges that lie ahead.

Jan 7, 1976

By Theodore H. Eyde

The Superior Oil Co. drilled two holes, 4720 and 5940 ft, respectively, using conventional oilfield rotary drilling equipment. The results indicated that large rotary drills can be adapted to mineral exploration purposes with few modifications. The principal advantages are: a large hole diameter, excellent samples of cuttings, a geolograph which is a constant drilling record, rapid penetration even in hard rocks, and the ability to use electric logs for measuring the properties of the rock being penetrated. The disadvantages are the high cost of mobilization, drilling, and oilfield service at remote locations. Though the oilfield sampling techniques are adequate for identifying lithology, improvements are necessary to obtain representative samples for analytical purposes. As deeper targets are explored, mineral exploration organizations will have to resort to rotary drilling.

Jan 1, 1975

By Richard S. Culver

In spite of the widespread interest in rock bolt research, relatively little is known about the critical region surrounding the bolt anchor. In analyzing the stress distribution around an opening resulting from rock bolt support, it is commonly assumed that the bolt is fixed at a point far enough from the surface so that the anchor does not influence the performance of the bolt. Furthermore, a bolt anchor is assumed to per- form satisfactorily if it will hold the design load with a minimum amount of load relaxation, commonly called bleedoff. From the standpoint of the design engineer both of these assumptions are reasonable, but they ignore the fact that the extremely high stresses in the region of the anchor are capable of generating fractures in the rock. Lang1 estimated the bearing stresses for a slot and wedge anchor on a one-inch-diameter bolt to be as high as 125,000 psi. This paper describes a more thorough analysis of the magnitude of the stresses around the anchor and the nature of the potential fractures that might result. It should be emphasized that there are two types of anchor-associated fracturing which may occur. The more common form, particularly in soft rock, is severe localized crushing of the rock in the immediate vicinity of the anchor, which makes securing the anchor difficult and causes bleed- off. It is also possible to develop larger single fractures which propagate out from the anchor, affecting the strength of the entire rock mass. The formation of these larger fractures is of primary concern in this paper. In addition to estimating the contact stresses and pullout load for slot and wedge bolt anchors, Lang carried out an important study of rock bolt interaction which served as a basis for the experimental phase of this investigation. In the first phase of his tests, a plate of photoelastic plastic was compressed by a row of piano wire bolts, simulating the interaction of bolt stress fields to form a zone of uniform compression (Fig 1). To show the supporting effect of this beam, hr carried out another test series

Jan 1, 1968

By E. Higgins

It is the purpose of this paper to set forth the relation and function of the various organizations and institutes engaged in the promotion of safety in the iron mines of the Lake Superior region…

Jan 1, 1915

By John A. Church

In May, 1878, I had the honor of presenting to the Institute, at the Chattanooga meeting, some observations upon the heat of the Comstock Lode, and since then the subject has attracted some attention and criticism, in the course of which, L have observed errors of apprehension which I beg leave to correct now. Mr. John Arthur Phillips discussed it before the Geological Society, his paper being printed in the Quarterly Journal for August, 1879." His criticism is based upon that part of my paper in which I quote a number of analyses of the mine waters, to illustrate the fact that the heat does not come from the oxidation of pyrite. I pointed out that these waters contain only an insignificant proportion of sulphuric acid, and not enough to account for even one per cent. Of

Jan 1, 1880

By J. Burbank

A TECHNIQUE has been developed for the microscopic study of the three-dimensional structure of the Pb-Sb alloys by the formation of a chemical replica in which the internal structure of the metal may be seen directly. In the replica process one of the phases present in the structure as-cast is converted into a translucent material, and the second phase remains virtually unaffected, permitting microscopic examination by transmitted light. Alloys of lead and antimony were made from the chemically pure metals, cast in a sooted and pre-

Jan 1, 1954

By David Branch, Martin J. White, Faramarz P. Hassani

The work presented in this paper is part of an overall research programme into the problem of stability of main access roadways driven in Coal Measure strata. Data about the post-failure behaviour of rocks are generally of a qualitative rather than quantitative nature. This investigation represents the initial part of a long-term research project aimed at quantifying the post-failure properties of Coal Measure rocks and to investigate their effects on tunnel stability. The results of tests conducted to evaluate the post-failure strength characteristics of Coal Measure rocks under uniaxial and triaxial stress conditions are presented. Empirical failure models are proposed to define the triaxial intact and residual failure properties of these rock types. The application of such data to closure prediction techniques of underground excavations are outlined and discussed.

Jan 1, 1984

By Robert S. Shoemaker

At this Symposium on Gold which is sponsored by The Metallurgical Society of AIME and the International Precious Metals Institute many distinguished authors will present the latest developments in the metallurgy of gold and in operating practices at mines and in refineries. It seems appropriate then, as the introduction to this volume to recall some of the history of gold and the metallurgical developments which have been accomplished, especially during the past 100 years and some of the people who have contributed so much to the metallurgy of gold. Of all the elements gold has been the most sought after since the earliest times. Perhaps the quotation from Virgil's Aeneid best describes man's desire for gold but Pliny the Elder also put it very well when he wrote in 79 A.D. that "Gold is the first of man's follies, silver the second". This quest for gold has markedly influenced man's history and through the efforts of the early philosophers and alchemists to turn base metals into gold the foundations for modern chemistry were laid. The pages of history literally teem with references to gold. Gold is the first metal mentioned in the Bible and was the source of Croesus wealth as well as the death of King Midas whose touch turned everything into gold. And of course almost everyone has heard of Jason's Argonauts and the golden fleece. They are the subject of one of the many drawings in Agricola's De Re Metallica published in 1556. The Argonauts were probably prospectors seeking the source of the placers in the region near-the Black Sea. The time was about 1200 B.C. and the placer miners recovered gold by trapping the particles in sheep's fleeces placed in sluices. After drying, the fleeces were shaken to recover the gold. Gold is not hydrophilic, or wetted by water and thus the oils in the wool aided in collecting the particles. Here we have perhaps the earliest reference to surface chemistry and the basis for concentration of gold by flotation.

Jan 1, 1984

By A. J. Chellew, Robert Condit

THE Company maintains a port agency at Antofagasta for dispatching copper and also for receiving from ocean vessels the vast variety of materials and supplies required at the plant. Copper shipments from the oxide plant refinery to Antofagasta amounted to 162,000 metric tons during 1951, while incoming freight totalled 175,000 metric tons. Electrolytic market copper in various shapes is currently loaded at the plant upon 20 or 30-ton cars of the meter-gage Antofagasta-Bolivia Railroad, to be transported a distance of 165 miles to the company's yard at Antofagasta. Here it is unloaded by cranes at the rate of about 175 tons per hr. Copper not scheduled for immediate shipment is stocked in tiers within the yard, but most of it is reloaded and sent to port works or a wharf serving lighters. Some of the vessels entering Antofagasta tie up at the port works, while others anchor inside the breakwater. In the latter case, all of the loading into the hatches is from 50-ton lighters towed to the vessel. When the vessel is at the dock, about half of the copper is loaded by port works cranes and the other half is loaded by ship's tackle from lighters. Fuel Oil Requirement Expands One of the innovations caused by the construction of the sulphide plant has been the necessity to provide facilities at Antofagasta for receiving and storing greater quantities of fuel oil than in recent years. From here it is loaded into tank cars for transportation to Chuquicamata. The older installation consisted of a 10-in. submarine pipe line, heating, and pumping facilities, a 67,500-bbl storage tank, and railroad loading rack, located at Antofagasta's northern limits. Two new tanks, of 80,000 and 30,000-bbl capacity respectively, have now been added and a second submarine pipe line will shortly be installed. Fuel oil requirements for the sulphide plant are estimated at 39,000 bbl per month, in addition to which 9000 bbl per month are required for the operation of the oxide plant. The company has a special lighter which is used by its diver for connecting the oil line with the oil tanker when disembarking oil, this lighter also being used for inspecting and overhauling buoys, as well as for recovery of bars of copper which are sometimes dropped into the bay when loading vessels during periods of rough weather. Transport of oil to Chuquicamata is by 76 tank cars of, 20-ton capacity and 20 of 30-ton capacity, all assigned to the company's fuel oil shipments excepting six for Diesel oil and one for gasoline. Incoming Freight Other freight received by the port agency has been averaging about 4800 metric tons per month of operating supplies for the oxide plant (renewals of equipment, spare parts, lubricating oils, and greases, etc.), some 1900 metric tons per month for the company stores, and about 6000 metric tons per month of materials and equipment for the construction of the sulphide plant. The greater part of these shipments (particularly the operating and construction supplies) originate from abroad, and must be handled through the Chilean Customs. Hence the company maintains a Customs storage warehouse (goods pending appraisal of Customs duties) in addition to its other storage facilities at Antofagasta. Not the least of the Port Agency's duties is to meet air and steamer passengers en route to Chuquicamata and to arrange for their trips up the hill. Landing in a strange country with a strange language, the first impressions of a new employee might otherwise be indeed confusing when facing Antofagasta's unique setting of brown barren hills.

Jan 1, 1952

By M. T. Simnad, C. E. Birchenall, M. H. Davies

THE marker movements observed by Davies, Simnad, and Birchenall during the growth of magnetite on wustite have been misinterpreted. It is the purpose of this note to correct the original interpretation. In that investigation wustite specimens were prepared by oxidizing pure iron disks in water vapor until the iron was consumed. Argon was used as a carrier gas for the water vapor and on the complete conversion of the metal to its oxides ('FeO' plus a small amount (10 pct) of surface Fe3O) the water supply was bypassed and the specimens were annealed in argon alone in order to equilibrate the wustite with the overlying magnetite. After cooling, the magnetite was ground off, a crude magnetic test being employed to determine its complete removal. Radioactive silver streaks were then applied to the surface and the specimen was oxidized completely in water vapor to prevent hematite formation. After complete oxidation the markers were found to enclose about 80 pct of the magnetite with the other 20 pct lying outside the markers. This observation was interpreted to mean that oxygen transport was four times as great as iron transport during the growth of the magnetite. The conclusion would have been correct if, as in the case of wustite growing on iron, all the iron had started from one side of the marker and all the oxygen from the other side initially. Actually a material balance is required. For simplicity, take wustite to be exactly FeO, and magnetite to be Fe3O,. Then at the start of the reaction 3 FeO + O -> Fe,O., All of the iron and three-fourths of the oxygen of the final product will be within the marker inter- faces. The other fourth of the oxygen is in the gas phase outside the marker. From the experimentally determined final position of the markers simple calculation shows that one-fifth of the total iron has crossed the marker interface, while one-twentieth of the total oxygen has crossed in the reverse direction. The simplified result favors iron transport in the ratio four to one. However wiistite is not stoichiometric FeO. At 900°C, the temperature of the measurement, the composition is about FeO When the material balance for the same experimental result is repeated, assuming the product will be 1 mol of Fe3O4, it is found that 0.6 gram atoms of iron and 0.19 gram atoms of oxygen must have passed the marker in the same direction. (This is readily apparent from the reaction to form 1 mol of Fe3O4 SFeO The total oxygen supplied from the atmosphere is 0.61 gram atoms, but the iron which passes the marker interface, i.e., 0.6 gram atoms, requires 0.8 gram atoms of oxygen to convert it to Fe,O,.) If all the transport during magnetite growth is due to iron ion diffusion, then the marker would enclose about 85 pct of the final magnetite and the original measurement is in error by about 5 pct. This error is probably less than the uncertainty in locating the markers by autoradiography. The possibility also exists that the starting wustite was not quite saturated with oxygen and underwent further enrichment with consequent envelopment of the marker before magnetite caught up with the marker interface. In any case it appears that these measurements actually favor iron ion diffusion in magnetite overwhelmingly as the factor controlling its growth, although further experimental measurements are needed to eliminate the error in material balance described. Such studies are planned.

Jan 1, 1954

By R. J. Weege, A. W. Schillinger

Conventional underground mapping methods and diamond drilling are being applied in a study to determine the nature of the copper ore occurrences near the footwall of the Osceola lava flow top, commonly referred to as the Osceola Amygdaloid. The work to date suggests that structures formed by relatively impermeable barriers, created by flowage and injection of still-molten lava from the interior of the flow into the solidified, brecciated crust, acted as the ore receptacles. Ascending hydrothermal fluids traveling near the footwall contact were trapped and confined in these barriers which retarded the direct upward movement of the ore fluids and caused deposition of copper. Oreshoots located near the footwall appear to have been formed spatially independently from the hanging-wall oreshoots by fluids traveling simultaneously, but along different channelways. The barrier concept, as advanced by earlier writers to explain the concentration of the ore-bearing fluids into broad shoots constituting entire ore bodies, is found to be equally as applicable for the localization of smaller oreshoots within the Osceola ore body. Recently, the Calumet Division of Calumet and Hecla, Inc. completed the unwatering of the old mine workings on the Osceola amygdaloid. Two shafts were subsequently reactivated and mining commenced on the Osceola lode after an idle period of over 20 years. Early in 1961, the Calumet and Hecla Geological Dept. was assigned the task of locating additional reserves. Accordingly, an intensive mapping and underground diamond drilling program was initiated. Except for a very few years following the first mining on the amygdaloid, the Osceola lode had never been a high grade producer. It was, therefore, recognized from the onset that a concentrated effort would have to be made by the mining, milling, and geological departments to insure success of the project. Company reports contained many references to ore that had been located near the footwall of the Osceola amygdaloid. Information concerning the grade of this ore was meager, but it was known that at least some was very rich. In contrast to ore that occurred near the hanging-wall, however, the footwall copper did not appear to have a systematic distribution and a large amount of poor rock had to be removed in developing this ore. This, of course, resulted in high development costs and discouraged any extensive mining of footwall ore. The possibility of more continuity than had previously been suspected was recognized by other workers, in particular Dr. T. M. Broderick, formerly Chief Geologist of Calumet and Hecla, who suggested attempts be made on a trial basis to follow the footwall contact with the main development drift. As most mining was done on the Osceola lode before a geological department had been established by the company, and almost all of these openings are now caved, very little information concerning the geology of footwall ore was available. It was, therefore, decided that the first step in the exploration program would be to become familiar with footwall ore occurrences by mapping the geology as the openings were driven. It was possible that a mapping program would reveal the features that controlled the localization of the ore. Furthermore, if it could be shown that footwall ore was more continuous, or if its distribution was more systematic than generally believed, it would be possible to produce a high grade ore that could be blended with the lower grade hanging-wall ore. In connection with the geological program, the Michigan College of Mining and Technology Geophysical Dept. under the direction of Professor Lloyal Bacon, is making a geophysical study of the problems of locating footwall ore by electrical methods. GENERAL GEOLOGY OF MICHIGAN NATIVE COPPER DEPOSITS The native copper deposits of Michigan are located in Keweenaw, Houghton, and Ontonagon Counties. The host rocks are Keweenawan in age and are comprised of interbedded sediments and lava flows which form a belt two to four miles wide and over one hundred miles long. These rocks form part of the south limb

Jan 1, 1962

Endurance Properties of Non-ferrous Metals Discussion of the paper of D. J. McADAM, JR., presented at the Syracuse Meeting of the Institute of Metals Division and issued, as Paper No. 1506-E, with Mining AND METALLURGY, October, 1925. H. F. MOORE,* Urbana, Ill. (written discussion).-This paper says that the results of tests of some non-ferrous metals made at the University of Illinois and in the testing laboratories at McCook Field are abnormal when they do not agree with results obtained by the author. The writer can see no inherent reason why results of the type uniformly reported in this paper are any more normal. The knee of the stress-cycle, or S-N, diagram comes at different lengths of life for different metals. For steel, the knee occurs after from 1,000,000 to about 4,000,000 cycles, and for some non-ferrous metals not before 20,000,000 of 30,000,000 cycles. The writer can see nothing inherently abnormal in finding certain nonferrous metals for which the knee of the stress-cycle curve occurs at 1,000,000,000 cycles or higher. The writer has had experience with both the cantilever and the rotating-beam testing machine, and thinks that the chance of whipping action in the cantilever machine is a more serious handicap than the action the author has pictured. Furthermore, the writer questions whether the author has shown the existence of a clearly marked and definite endurance limit for all the non-ferrous metals he has tested including the following: Nickel (CT and A-16, Fig. 1), monel (CS-5.5 and BK, Fig. 2), bronze (F and CK, Fig. 4), aluminum bronze ( BJb-1, Fig. 6).

Jan 12, 1925

By F. Louis Grammer

The following study of flue-dirt and the influences controlling it may be interesting to many. It is published because it represents observations at about thirty furnaces at different times. It may assist in giving an impetus to the making of similar observations elsewhere. Until ten years ago, the metallic waste in furnace-gases was not considered a problem of pressing urgency in iron metallurgy—certainly not in the blastfurnace end of it. Many plants at present ignore, or pay but little attention to, top-pressures. Prior to the introduction of Mesabi ore, the losses in escaping gases, if considered at all, were regarded as thermal losses, or losses of fuel (except by those interested in lead, zinc, silver, etc.). In a high-priced material like ferro-manganese, such losses were, indeed, considered important. But the behavior of the Mesabi ores, corning, as they did, in practically inexhaustible quantities, could not be disregarded by the furnaceman. These ores came to stay. The tables appended below have purposely been altered to disguise the plant, the company and the ores used. The comparative values are maintained. In these tables, the influencing elements and conditions which are constant, or practically so, namely, size of furnace, quantity of wind, fuel used, etc., are not mentioned. The figures represent observations consistently followed up for a long period. The weights of flue-dirt were obtained from cars on which no other dirt was thrown. The analyses and calculations are based on the best of sampling. The effects of slips are excluded. Slips should not occur at well-regulated or properly-constructed furnaces, excepting under unusual and rare conditions. Allowances are made for moisture, scrap charged and silicon in the metal. The cutting effect of Mesabi

Jan 1, 1904

Discussion of the paper of J. V. EMMONS, presented at the Pittsburgh meeting, October, 1914. and printed in Bulletin No. 93, September, 1914, pp. 2233 to 2248. ALBERT SAUVEUR, Cambridge, Mass.-Mr. Emmons is to be congratulated for having placed before us in so forcible and satisfactory a manner a question of much importance-that of the surface decarbonization of steel. Of course, both manufacturers and consumers have known for many years that during the heat treatment of high-carbon steel, surface deca.rbonization is always likely to occur to a greater or less degree, but the subject does not seem to have been investigated with the method and thoroughness it deserves. I am in substantial agreement with Mr. Emmons's conclusions, and I have but little to add to what he has so well said. His statement that carbon dioxide is just as effective an oxidizing agent as pure oxygen is likely to cause surprise and some will wonder whether his investigation has been carried far enough to warrant so unexpected a conclusion. The reaction C + 0 = CO, expressing the oxidation of carbon by pure oxygen, is decidedly exothermic, whereas the reaction C + C02 = 2C0, expressing the oxidation of carbon by carbon dioxide, is endothermic. Decarburization by pure oxygen, therefore, should take place much more readily than by carbon dioxide. One cannot help regretting that the author does not mention' the best way of preventing in a practical manner surface decarbonization while treating tool steel and other high-carbon steels.

Jan 4, 1915