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By Leonard Larson

DURING several years immediately preceding the adoption of wet-charge smelting at McGill, various necessary conditions affecting this procedure, such as plant rearrangement and the metallurgical nature of the concentrate produced at the concentrator, were fully considered. Wet-charge smelting is not altogether novel to the recently reconstructed smelter at McGill. A number of years prior to this improvement, when flotation methods were initiated at the concentrator, large tonnages of wet and (at that time) sticky flotation concentrate were charged directly into the reverberatory furnaces, because of the difficulty in handling the entire tonnage in the roasters. The plant had excess reverberatory units and this surplus furnace capacity was utilized to smelt raw flotation concentrate. During the years 1927 and 1928, a number of actual operating furnace test runs were made to determine in principle the feasibility of wet-smelting operation. Results were encouraging, and in November 1932 the roasting plant was shut down. For some time thereafter the wet feed was delivered directly to the reverberatory side-charging calcine hoppers already in place. Feeding the wet material through the old calcine hoppers and charge holes into the furnace involved considerable labor, but under the conditions existing at that time it was desirable to continue wet smelting even under the handicap of this laborious procedure. The smelting plant during this period was on a curtailed production basis, operating only about 15 days per month. The alternate starting up and shutting down of the roasting plant presented a difficult problem and charging the wet material directly to the furnace entirely eliminated this difficulty. The roasting plant was never operated thereafter. EARLY PROCEDURE Fig. 1 shows the general layout of the smelting plant before the smelter was remodeled. Under this arrangement, all concentrates and fluxes except converter flux were delivered in cars to wooden storage bins, which paralleled the roaster building. The material to be roasted was dis-

Jan 1, 1938

By F. W. Metzger

INTRODUCTION Coal quality control in mining and mine planning has always been important and has become even more essential in recent years due to environmental considerations. The primary consumers of the sub-bituminous coals found in the Powder River Basin are electric utilities that require low sulfur coals to meet government air quality regulations. Electric generating plants are designed to burn coal of a specific quality, and the supplier of that coal must be able to guarantee shipments within specified quality tolerances. Over the past several years, Exxon Coal USA and, more recently, The Carter Mining Company, a division of Exxon Coal USA, have established an evaluation and development program to accurately define the geology and quality of their coal properties. This requires an adequate drill hole density so that detailed correlations of the coal seam and the lithologic units, or benches, within the coal seam can be made. These units are recognizable in the core and also on geophysical logs. Like any systematic approach, geologic modeling has been refined and improved through new technologies. Today, coal seam properties are mapped using computer applications. Rapid access and manipulation of these data allow for optimization of mining efforts. This presentation will demonstrate how a detailed mapping program can be important in both pre-mine development and in-pit quality control.

Jan 1, 1983

By O. Hall

DIAMOND drilling has become a very important factor in mining. It is the most satisfactory method of obtaining proof of the existence of an orebody and of determining the character and extent of the body, in measures where a core can be made. Large investments are based on the information obtained. The method of development, the mine and reduction plants, and subsidiary essentials as railways are often built without other information. The Mond Nickel Co. has drilled about 50,000 ft. (15,240 m.) per yr. for several years and has given considerable study to the question of improving the methods and of overcoming the limitations of this means of securing information. One of the main limitations of the diamond drill has been its inability to drill a straight hole. To depths of 1000 ft. (304 in.) the deflection is often not large but all holes tend to curve and take somewhat erratic courses. A hole running at a small angle to a fissure plane tends to run, along the fissure. If the hole is at a large angle, the tendency is to penetrate the fissure plane at right angles. The face of the bit having one side in solid formation beyond the fissure, the other in the selvage of the fissure tends to turn, the rods curving to the extent of their clearance in the hole. Usually rock measures have somewhat regular fissuring or strata and holes take somewhat similar courses, usually at right angles to the fissuring or strata. Excessive pressure or short or worn core barrels increase curvature. Slow speeds, correct feeds, sharp hits, and core barrels the full size of the hit, tend to decrease curvature but do not prevent it Curvature once started increases rapidly. The disappointments from crooked holes have been numerous. Discoveries have later been found to be on the properties of others. One Canadian company had a hole, supposedly discovering ore 300 ft. (91 m.) from old workings, unexpectedly turn in 8 ft. (2.4 m.) of wooden core from a timber in the old workings.

Jan 9, 1919

E L. DEGOLYER, our new president, though a petroleum geologist by profession, has always s been associated with mining, for soon after his birth at Greensburg, Kan., on Oct. 9, 1886, his parents moved to Joplin, and when he went, in the course of time, to the University of Oklahoma, he intended to follow his course there with another at a mining school. He became a field assistant in the U. S. Geo-logical Survey, however, while still an undergradu-ate, and after field experi- ence in Montana, Wyoming, North Dakota, Colorado and Oklahoma, he went to Mexico as geologist for the Mexican Eagle Oil Co. This was in 1909, and as a result he was unable to complete his work for his degree until 1911. In Mexico, he located the Potrero de Llaño No. 4, one of the world's largest oil wells, and also the dis- covery well in the Naran- jos pool; and the Colorado School of Mines conferred the honorary degree of : Doctor of Science on him in 1925. On his return from Mexico, he engaged in the consulting business, specializing in financial ap- praisement, the Union and Marland companies being among his clients. In 1919, he organized the Amerada Petroleum Co., with the backing of Lord Cowdray. Last year, control of the company was purchased by an American group, headed by Dillon, Read and Co. Mr. DeGolyer is n o w president of the company. He is also vice-president and general manager of the Rycade Corp, the Rycade Oil Corp., and president of the Geophysical Re-search search Corp. The l a t t e r represents the practical appli-cation of his inter-est in the use of the torsion balance in the locating of salt domes, in which he has pioneered, the Nash dome being the first oil field in America actually brought into production by these methods.

Jan 3, 1927

By S. F. Reiter, R. W. Guard, J. H. Keeler

DURING the last several years the authors have been conducting tests on a tensile machine that autographically records load-elongation data. In certain tests at elevated temperatures on face-centered cubic, hexagonal close-packed, and body-centered cubic materials (binary alloys of nickel, zirconium, and iron), the load-elongation curve as shown in Fig. 1 reaches a maximum load (Pmax,) at relatively small amounts of strain and a large amount of elongation occurs subsequently with a continuously decreasing load, until finally localized necking and fracture take place. This early maximum load behavior has been found without the accompanying evidence of localized necking as has been assumed by some, or of evidence of cracking as observed by others.' This behavior has also been observed by Nadai and Manjoinez whose results are in good agreement with ours. The prior strain, strain rate, test temperature, and crystal structure affect the observations. The influence of prior strain was observed in tests on unalloyed zirconium at 300°C in which specimens containing large amounts of prior strain (cold work) exhibited the type of curve shown in Fig. 1. No localized necking was observed after strain as much as that of point B. Annealed and recrystallized specimens of the same material showed a load-elongation curve with maximum load occurring after considerable strain hardening and at the beginning of localized necking. Interrupted tests (Fig. 2) show no loss in strength because of recovery or recrys-tallization during an interval at temperature without load. Recovery under stress such as found by Wood and Suiter3 in aluminum is now being investigated as one possible explanation. The strain rate is a contributing variable as shown in Fig. 3, a test on high purity nickel. Here the strain rate was decreased by a factor of ten during a test in which the maximum load was reached at a small strain. The slope of the true stress-true strain curve was positive with the more rapid strain rate and negative with the slower strain rate. In many binary ferrites an added effect of temperature has been observed. Fig. 4 shows the load-elongation plots for a binary ferritic alloy containing 2 pct Mo. The slope of the small portion of the stress-strain curve obtained at a strain rate of 0.01 mhr1 changes sign from negative to positive on going

Jan 1, 1955

J. S. UNGER,* Pittsburg, Pa, . (written discussion?).-The author of the paper has given an excellent description of the appliances used to cool parts of an open-hearth furnace, and some of the reasons why the refractories fail in service. Personally, I favor water-cooling, but to a limited degree. At one time I advocated more universal cooling than is now practised, but believe I must change my mind. Water-cooled, thin-lined blast furnaces have not proved as satisfactory as anticipated. While this may retard the building of many such furnaces, it will not prevent the use of regular tuyere- and bosh-cooling appliances. Water-cooling any furnace may be easily carried to the extreme. In an open-hearth furnace, excessive port or roof cooling, or cooling the working floors may preserve the lines of the furnace, lower the cost of refractories, acid to the comfort of the workmen, and necessitate fewer shutdowns for repairs, but it may not be good economy on account of the high first cost, the cost of cooling water, maintenance of cooling appliances, and the immediate reflection in a higher fuel cost. The question becomes a financial one, and is answered by using water-cooling devices up to the point at which they cease to show true economies. Open-hearth furnace bulkheads, roofs, and ports fail rapidly in about the order named. If they could be made to last indefinitely by water-cooling, the furnace would still have to be shut clown periodically for cleaning the slag pockets, regenerator chambers, and flues. Extra, or spare, pockets and regenerator chambers have been advocated to permit of continuous operation, but the space required, the cost of installation, and the fuel required to initially heat such cold chambers will largely prevent their adoption. Some particular fuels, as high-ash powdered coal, require frequent stoppages for cleaning, but for this particular fuel a special provision can' be made.

Jan 5, 1919

By W. A. Backofen, R. L. Fleischer

AN effect of orientation on the creep behavior of aluminum at 4.2 OK has been observed. Stress relaxation was measured in a hard-type tensile device after stopping the drive. From the spring constant of the device the load-time record could be converted to strain as a function of time. The strain sensitivity was 2-10-=, and the usual creep time of 1 min normally allowed a stress drop of about 25 g per sq mm. Further details of the apparatus and sample preparation appear elsewhere.' It should be noted that neither stress nor strain were constant, so that quantitative comparison with current creep theories will not be made. Shear strain (y) as a function of time (t) was consistent with logarithmic behavior: y = A In t, where A is a constant. In some cases t was made as large as lo3 sec. In the results the quantity A divided by t (the resolved shear stress, which is the driving force for creep) is plotted as a function of strain prior to creep. The quantity A/t is thought to indicate qualitatively the ease with which dislocations can move during creep. In Fig. 1 are drawn tensile stress-strain curves and A/T-strain measurements for single crystals of three orientations: l(a) and l(b) for the maximum resolved shear-stress orientation, l(c) for an orientation 2 deg from [211], and l(d) for a [111] stress axis. The following observations were made: 1) At low strains the A/t values are nearly the same for the three orientations. 2) As strains increase, A/t drops most rapidly for [Ill.] and less rapidly for [211], while for the maximum shear-stress orientation it is constant during easy glide and drops abruptly at the termination of easy glide. 3) In stage 11, A/t values are again approximately the same for the three orientations. These observations are regarded as evidence that 1) the initiation of slip produces obstacles of essentially the same effectiveness for all of these orientations, while 2) the rate at which slip obstacles are produced before stage I1 is fully developed is strongly controlled by the amount of slip on more than one system. This second statement is consis-

Jan 1, 1961

INSTITUTE MEDALS AND PRIZES ASIDE from the John Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the Institute itself has five major awards to make annually for excellence in technical papers, as follows The Robert W Hunt Medal, The Hadfield Prize, The J E Johnson Jr , Award, The Lewisohn Platinum Prize to senior members, and the President's Prize to junior members ROBERT W HUNT MEDAL The partners of Robert W Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules, 1 The award shall consist of two prizes, first of a gold medal, second of a sum of money, a certificate to accompany each prize The money prize shall not be awarded to a member over 40 years of age, but under unusual circumstances, both prizes may be allotted to one person provided that he is not over 40 years of age In general it will be understood that the Committee shall award the money prize to, the younger men, rather than the medal 2 The awards shall be made not oftener than once a year to that person or persons contributing to the Institute the best original paper or papers on iron and steel The scope of the term "iron and steel" shall be determined by the sub-committee consider¬ing the awards In general, papers dealing with the practical side of the subject have preference over those dealing with the theoretical side in recognition of the fact that Captain Hunt's main contributions to the industry have been in the improve¬ment of production and quality of material 3 A sub-committee of three to five, including the Chairman of the Iron and Steel Committee, shall be appointed by the Iron and Steel Committee annually to adjudge the award subject to approval 4 The awarding committee shall submit its report to the Iron and Steel Committee at its October Meeting, and the award be certified to the Secretary of the Institute in time to permit the presentation to be made at the Annual Meeting of the Institute 5 The recipient of the award shall be designated "The Hunt Medallist "

Jan 1, 1923

By S. H. Ash

THE increasing need for the products of our mines, mills, and processing plants, the loss of mine manpower to plants other than those concerned with the mineral industry, and the drafting of our younger men into military service have created an acute situation in many places as to workers and production. This, in turn, has focused attention on the need for conserving manpower by conserving the health and life of our mining people. Health A world-wide tendency is noticeable in the mineral industry toward protecting the health of workmen,-particularly younger workers, as well as older workers who can continue to produce in many places where manpower is lacking. This matter was emphasized at the Geneva Labor Conference for Coal Mines at the Committee's fourth session, held in Geneva, Switzerland, May 7 through 19, 1951. Papers concerning the health of workers were presented at the annual meetings of the mining sections of the National Safety Council, the Coal Mine Inspectors' Institute of America, the American Public Health Association, and other organizations. Safety Conferences Without exception, the attendance at mining-safety conferences in widely separated places throughout the country during the year was the largest to date. What is needed at the safety meetings throughout the country is more-widespread attendance by those who can sell the idea to the workers that they are the focal point in accident prevention and that safety is not going to be achieved alone or even in part by laws, decrees, or commands, but by quiet influence, unconscious suggestion, and personal' guidance. If these are acquired by the workmen, a safe environment and ample, capable supervision supplied by management, accidents will be fewer and less severe. Many safety conferences attempt to develop the foregoing idea by enumerating and describing training programs for supervisors and workers alike. Nothing can replace a course in first aid for all persons employed at any mine or plant as an introductory and basic step to a successful safety program. Even in this, the shoe must fit the foot, rather than applying the order do this or else. In first-aid

Jan 1, 1952

By O. I. Deschon, Ralph Arnold

Deep drilling was the keynote of the more important developments in the North Rocky Mountain region during 1929, with Montana recording the most important achievement through discovery of three new oil fields. Alberta produced 1,000,000 bbl. of 74 gravity naphtha, showing a considerable gain over 1928, developed a commercial oil pool in Turner Valley and extended that field 8 miles southward. Wyoming's discovery field was deepened to a second producing horizon, giving impetus to deeper drilling, and practically every Wyoming oil field will have a deep test either this year or in the near future. Whereas Montana prospecting has been confined to the shallow plains structures, since the discovery of Kevin-Sunburst field, the coming year will see an active search for new oil and gas pools in sharp-dip structures, following the success of prospecting in the Sweetgrass Hills during 1929. A dozen or more structures have been mapped in North Central Montana, several of these straddling the Alberta border. Four structures tested thus far have all shown commercial oil or gas or both. Sweetgrass Hills The first important development in the Hills area was the Rogers-Imperial gasser, which had an initial of 51,000,000 cu. ft. of dry gas per day, with a rock pressure of 1080 lb. This well is located on a sharp nose running north from the hills into Alberta. Several wells drilled by independent operators on the American side, on the west flank of reserve structure, have developed a total open flow capacity of 30,000,000 cubic feet. The third structure tested in the Hills area is known as Bears Den, where commercial oil was found at the base of the Cretaceous at 2470 ft. The existence of oil in three lower sands has been established by two wells on the top of the structure, these two wells finding gas flows of 10,000,000 and 15,000,000 cu. ft., respectively, in the horizon where

Jan 1, 1930

By W. M. Clark

OUR interest in the matter of pyrometers and pyrometry is primarily that of a user of considerable quantities of heat-measuring equipment; and while we play be somewhat critical on the subject we have aimed to make the nature of these comments constructive. The glass industry in America dates back to 1609, when Capt. John Smith started a small glass plant near Jamestown, Va., with a few Italian workmen, to manufacture glass beads for trading with the Indians. While the industry has expanded until it has reached a volume of over $200,000,000 per annum, the means of heat determination in Colonial days was the human eye, and in much of the industry the same means is used today. About 15 yr. ago the largest glass-house supply dealers began to sell platinum pyrometers, but as nearly all of these proved un-satisfactory, pyrometers met a temporary rebuff from the old-time glass manufacturers. As their ruggedness of construction, reliability, and stability have been improved, however, pyrometers have gradually won their way into more and more extensive use throughout the glass trade. But there are still many applications where pyrometers are not used, largely because of cost and upkeep considerations. There are two distinct fields in glass works for pyrometry. The first calls for accurate temperature measurement and the second only demands knowledge of relative comparative fluctuations of temperature, to know whether the work is becoming hotter or colder. For example, in a lehr for annealing glassware and removing strain we want accurate temperatures to know that the ware is heated to the critical temperature for rapid removal of strain. On the other hand, in a glass pot furnace nearly 120 ft. (36 m.) in circumference, where the pyrometer couples only project inside the furnace wall for less than 2 in. (50 mm.), it is inconceivable that these few inches represent the accurate temperature at every point of the 120-ft. circumference but the relative readings as to whether the pyrometer shows schedule temperature fluctuations are valuable indications for control. The glass melting in the pots is,

Jan 8, 1919

By A. C. Fieldner

A FORMER paper1 described in detail various methods of calculating coal analyses to obtain the composition and calorific value of the pure coal substance-that is, of the coal free from its mineral matter. The paper included a table showing calorific values of pure coal, as calculated from float-and-sink portions, by means of the Parr formula for "unit coal" and by the customary moisture-free and ash-free formula. A modification of the Parr formula was proposed, based on the assumption that one-half the sulfur present in coal occurs as pyritic sulfur and one-half as organic sulfur. In the published discussion of the paper Cady gave a table of results on a large number of Illinois coals as obtained by the Parr formula and the proposed modification thereof. The results obtained by Cady indicate that the Parr formula applies better to Illinois coals than does the modified formula proposed by Fieldner and Selvig. The present paper gives results obtained by applying the modified Parr formula to the analyses of the float-and-sink portions of the coals shown in the former paper, and results obtained by applying the Parr formula, the modified Parr formula, and the simple moisture-free and ash-free formula to various coals of the United States ranging in sulfur content from less than 1 per cent to more than 4 per cent sulfur. A graphic method of estimating the calorific value of pure coal and determin-ing the relation of the coal ash to the mineral matter of coal, as proposed by Stansfield and Sutherland,2 was applied to a number of coals, and the results are given herein.

Jan 1, 1932

By Felix Shay

THE Agua Fria mine is in eastern Honduras at Lat. 140° 06' N., Long. 86° 36' W. Danli, the seat of the local municipal government, is the nearest town. The property is approximately 44 miles east of Teguci-galpa, the terminus of a truck road from the Pacific coast. The mine lies at an altitude of 3300 ft. with surrounding elevations as high as 6000 feet. For 20 years the oxidized croppings of the Agua Fria vein had been worked intermittently when in 1927 an attempt was made to open the property. A shaft was sunk 300 ft. and considerable ore was blocked out, but before a mill could be installed financial difficulties arose and the mine reverted to the original owners. Erle P. Halliburton, of Los Angeles, purchased the property in 1934. At that time a careful consideration of all factors involved showed that air transport was the only practical method of moving the equipment and machinery necessary to commence production. The other alternative was by muleback, which required sectionalizing all equipment to a maximum load of 200 lb., and during the rainy season this type of freighting was subject to serious delays. It was decided to purchase a trimotor Ford powered by three Pratt and Whitney Wasp B motors developing 400 hp. each. There were several reasons for the choice: (1) this type of plane was available at a reasonable price, owing to its replacement by faster models on most of the airlines in the United States; (2) the ship was capable of carrying a pay load of 3000 lb. over the required distance; (3) since this airplane had been widely used there would be no difficulty in securing competent personnel or in purchasing spare parts. It was necessary to rebuild the plane for cargo service. The windows were removed and the fuselage was entirely covered. A hatch was cut in the top of the fuselage to receive heavy crane loads and pieces of freight that were too large or too long to go through the rear door. The seats were removed and the interior of the plane was lined with Duralumin sheets. A heavy-duty landing gear was installed and the floor was reinforced.

Jan 1, 1940

By H. Case Willcox

AERIAL photographic surveying and mapping is not new or unknown to geologists. However, it has been utilized but little before, principally because it is only within the last few months that practical means of adapting this method to the requirements of petroleum companies have been discovered. No American aerial survey company has taken up aerial surveying and mapping as an engineering service to be offered to petroleum companies and their geologists for use in undeveloped and jungle-covered petroleum areas. This method of surveying and mapping, however, is used by the War Department, the U. S. Reclamation Service, and Geological Survey, and the corresponding Departments of the Canadian Government. ADVANTAGES OF AERIAL PHOTOGRAPHIC SURVEYING AND MAPPING The advantages of aerial photographic surveying and mapping to petroleum companies and their geologists are many. One of the most valuable is presented in the very first phase, or the exploration period. It is assumed that, when convinced that petroleum possibilities are present, a petroleum company has secured a concession of 8000 sq. mi. of unexplored area in Eastern Venezuela. The company may either have the entire area surveyed and mapped by the aerial photographic method, or send its chief field geologist up in an airplane so that he, from-an aerial reconnaissance, may reject certain portions that, for geological reasons, the company would not be interested in. He will then point out the regions that are to be surveyed and mapped. After the air-work is completed, the results are brought down, developed, and printed; then the resulting "contact prints" are given to the field geologist. They may be roughly assembled to give a general idea of the property in its entirety, or they are in shape to be examined in adjoining pairs under the stereo-scope. With this instrument, the geologist is enabled to make a minute examination of surface indications. The work of assembling and constructing a complete general or detailed map, according to the scales desired by the petroleum company and for the later office use, is continued by the aerial photographic company.

Jan 3, 1925

By Hillary W. St. Clair

An equation is derived for the rote of reaction of a sphere of metal oxide in a restricted enclosure through which a reducing gas is flowing. The equation takes into consideration the reaction rate coefficient, transport through the gas and through the porous shell of reduced oxide, the rate of gas flow, THIS paper describes a mathematical study of the chemical and physical processes that determine the rate of reduction of solid metal oxide with a reducing gas. The study was a part of a theoretical study leading to the development of a mathematical model for the simulation of the thermochemical behavior of the iron blast furnace. An essential feature of such and the volume of- space surrounding the sphere available for gas flow. The equation is applied to experimental data on vote of reduction of iron oxide in hydrogen. The equation serves as a model for predicting the course of reduction of a particle of. metal oxide in a shaft furnace. a model is an adequate mathematical relationship defining the rate of reaction in terms of all the important chemical and physical phenomena that affect the rate of reaction. This includes not only the reaction rate coefficients, equilibrium ratios, gas composition, and temperature, but also the relevant physical properties of the oxide, rate of gas flow, and relative volumes occupied by gas and solid. In many previous experimental studies of the rate of reduction of oxides by hydrogen or carbon monoxide, the rate of reduction was assumed to be controlled primarily by the chemical reaction at the

Jan 1, 1965

By Henry M. Howe

If a bar of wrought iron or steel is suddenly cooled from a bright red-heat, the contraction which then occurs is considerably greater than the expansion previously caused by heating the bar, so that its final length is considerably less than its initial length. Mr. Thomas Wrightson has investigated this phenomenon,* and has shown that not only does this permanent contraction occur on sudden cooling, but, if the heating and cooling be repeated, say fifty times, a further permanent contraction occurs at each successive cooling. In Mr. Wrightson's opinion, this contraction cannot be explained on mechanical grounds, and he ascribes it to some molecular change caused by sudden cooling; but I think that we need not invoke mysterious molecular changes to explain this phenomenon, which appears to me to be due to very simple and purely mechanical action. Let us consider the cooling as divided into two periods, in the first of which the exterior or skin of the bar becomes almost completely cooled, and hence tends to contract almost to its initial dimensions, while the still hot arid plastic interior contracts but little; in the second period the already cool skin remains nearly constant in temperature, and hence tends to contract but little, while the interior cools from a comparatively high temperature to the ordinary temperature, and hence undergoes great contraction. The excess of the contraction of the skin over that of the interior during the first period tends to make the bar bulge in the middle of its length. This, as well as the decrease of density which occurs, Mr. Wrightson correctly explains. The interior of the bar just sufficed to fill the skin when both were in their initial condition, before being heated at all. At the end of the first period, the volume of the still hot interior is more than the now contracted skin can hold while maintaining its initial shape; and the effect is much the same as when we powerfully blom into a soft India-rubher Lag of the shape of the skin of the bar—it bulges, and tends to approach the spherical shape, in which the ratio of surface to

Jan 1, 1886

By Yap Chu-Phay

IN the previous paper, the writer showed how, on the basis of thermodynamic reasoning, it seems probable that when true equilibrium conditions obtain, carbon exists as Fe3C in the liquid state and as elementary carbon in the solid state (7 Fe), in which case the solidus would be a straight line from 0.18 to 1.70 per cent. carbon (Fig. 1). In the same paper he concluded that the solidus obtained by Honda 'and his co-workers1 probably does not represent the same conditions, insuring a complete equilibrium. Except for a downward temperature displacement, the solidus obtained by Gutowsky,2 using the Heycock and Neville method, practically coincides with Honda's solidus as shown in Fig. 1. The writer at first thought that perhaps in some way Gutowsky's thermocouple was improperly calibrated for high-temperature measurements, as his liquidus was also much lower than those obtained by Carpenter and Keeling3 and by Ruer and Goerens.4 However, the eutectic temperature obtained by Gutowsky agrees with the generally accepted value of 1130° C., so that the validity of the inference regarding improper temperature calibrations is to be strongly doubted. In Fig. 1, Gutowsky's solidus is shown both in the original and in the corrected form. In the latter, a correction of 29.2° C. is made for all temperatures above 1416° C. in accordance with-

Jan 1, 1931

I. N. KNAPP, Ardmore, Pa. (written discussion *).-The writer would first call attention to the fact that the mid-Continent field was credited from 1900 to 1915 with a production of about 641,000,000 bbl. of oil with-out any burdensome water troubles being reported. In fact, the authors say the conditions were not acute until about two years ago when the unusual conditions in the deeper oil fields were first encountered. The writer disclaims any personal knowledge of the district mentioned but, from the experience he has gained in directing drilling in various fields by both the cable-tool and the rotary methods and also in plugging and cementing wells, he fails to see how the analysis of water trouble given in the paper under discussion could be of any practical assistance in solving the problems so vaguely outlined. Possibly it might induce academic discussion, if not limited to practical operating conditions. A recent bulletin of the Bureau of Mines gives definite and practical statements that can be easily understood by one skilled in the art of drilling wells and heading off water troubles. From an operating standpoint subsurface knowledge must be based on logs of completed wells. Absolutely no one can have such knowledge as that indicated in Fig. 1 of the paper in question without drilling wells, and no one can question such facts when disclosed by the drill. Under classification of water the paper states "This water (primary) cannot be exhausted from the sands, but its encroachment can often be checked and so directed that wells need not be abandoned, until most of the available oil is secured." This is a live question to the writer. A couple of years ago he had some wells drilled and found the conditions comparable with sands A and D of Fig. 1 with B and C left out; but nothing in the paper, so far as can be found, indicates how this water encroachment is or can be checked or directed particularly under the High heads named.

Jan 5, 1919

By Enrique Touceda

As IN the case of steel and the non-ferrous alloys in general, the use of the microscope in connection with the manufacture of malleable cast iron has proved of inestimable value to the industry. Had its use not been invoked, many facts either would not be known at all or, if suspected, would be confined to the realms of conjecture. No fairer statement could be made than that the start of real progress in the industry was coincident with the application of metallography to the product, though the full significance of this statement can hardly be appreciated except by those who not only are conversant with conditions as they existed at the time referred to, but are familiar with the character of works' practice at the present time. A few years ago, about the only test made to ascertain the physical properties of the product, t except in the case of certain plants, was the bending of a casting to destruction, not only with the object of discovering whether or not the metal was ductile, but for the purpose of inspecting the fracture. The characteristics of the fracture, if correctly interpreted, were known to be of value in locating the trouble in, castings that were inferior. In general, it was found that if a casting of medium or heavy section would bend through a wide angle before failure took place, the fracture in the majority of cases would have a black velvety appearance; while if it was held at different angles to the direction of the rays of light, it would show a change of color and an iridescent sheen. But an inferior air-furnace heat or anneal might yield castings which, if thin and consequently largely decarburized, could be bent double on themselves and still not possess the fracture described. If, on the other hand, a casting broke short, its fracture might have one of a great many different color and structural peculiarities. Depending on the cause of the trouble, such castings might have any of the fracture characteristics, of which the following is but a partial list.

Jan 2, 1920

By Francis Peabody

THIS paper will not be a technical paper, because, although I have been in. the business of mining and selling coal for 30 odd years, I am neither a mining engineer nor a practical miner. If I digress from time to time from my thesis, I must be forgiven by the expert engineers and highly technical gentlemen for whose proceedings this article is written. Waste of the wonderful store of power that the Creator placed at our disposal appears to have been the theory and the basis of our methods of extracting this power-waste from the time the coal is mined to the time it is consumed. Let us consider the prime causes of this wastage which has been the heritage of the coal mining industry. In the early days-about 150 years after "Stone Cole" was discovered in Illinois by Joliet and Marquette, and Father Hennepin noted a, "sole" mine on his map-the mode of mining prevalent among farmer land-owners, on whose property coal was discovered near the surface or outcropping on the hillsides, was to enter the seam by a shallow shaft or drift into the hillside and remove the coal by wedging it down until a large room was left. The roof without support would fall and our primitive coal operator would then sink another shaft or drive another drift. In these early operations only the large lumps were taken and all small pieces and screenings were left to be covered by the fall of the roof-in fact this condition prevailed in Illinois up to about 1885. Gradually the method of mining changed from the open chamber, to a single entry with rooms turned to the right and left. Later, as the demand for coal increased and the necessity for larger mines became evident, the "room and pillar" system grew to be regular practice.

Jan 5, 1917