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By S. C. Robinson

"IntroductionALTHOUGH most uranium deposits of the Canadian Shield lie along its western and southern margins, those of the Lake Athabasca region extend easterly along the north shore of the lake and beyond to Charlebois lake. The western end of this belt of deposits, in the vicinity of Goldfields, is 80 miles from the Palaeozoic contact, and its eastern end, at Charlebois lake, is 240 miles from the nearest Palaeozoic rocks.Deposits in this belt may be grouped in four districts, which are, from west to east:(1) The Goldfields district, an area approximately 20 miles square, centred on Beaverlodge lake and extending eastward from St. Joseph's point to Moose channel.(2) A small area in the vicinity of Sucker bay, which is about l0 miles east of Fond du Lac.(3) An area including Middle lake to the northwest shore of Black lake at the Nisto mine.(4) A fairly large area extending northward from the eastern end of Black lake, through Charlebois lake to Spreckley lake.HistoryThe region has stimulated interest in mining circles since the reconnaissance survey of J. B. Tyrrell of the Geological Survey of Canada in l893, who reported concentrations of iron along the north shore of lake Athabasca. The deposits were staked and re-staked up to the early 'twenties' but are too lean to form ore."

Jan 1, 1952

By H. Furman Byars

INTRODUCTION of bottom dump hauling units into the Ray, Ariz., stripping operation of the Isbell Construction Co., was motivated by several reasons, with what appears to be debatable results. The accepted theory of truck design for use in open-pit holds that end dump vehicles are the most adaptable for the work. But, because operations of the bottom dump, under certain construction and haulage conditions, proved economically feasible, the unit was put to work in the Ray copper pit. The decision to try bottom dump was reached after considerable observation of the unit in action on construction of earth filled dams, levees, airport construction and several other similar tasks. Basic tire design also motivated the choice. All things being equal, a vehicle running on low pressure single tires will outperform another operating on dual high pressure tires, providing load carrying capacities are the same. The investment required to equip a vehicle with four single tires to handle the same load as one with dual tires mounted on two axles and single front axles is about 60 pct greater. Thus, in order to reach the break even point on tire costs, single tires must operate 60 pct longer. Comparison is made with a truck outfitted with 10 16:00x25 tires. Two other factors were considered in selecting bottom dump trucks. It was felt the bottom dump principle would work well in dumping ore into a hopper where gate design fits this particular method. Also, with the absence of hydraulic dumping, ore pollution with oil is reduced. The mechanical simplicity of the unit also lent weight to its choice. Ordinary reasoning indicated maintenance costs would be low compared with other units carrying similar loads. The bottom dumping principle is not new. It dates back to the days when horses were used to haul the same kind of rig. The unit employed at Ray holds 25 cu yd struck measure, or approximately 42 short tons. Dumping is accomplished by releasing an air cylinder opening a dog holding the doors. Doors are closed by a cable system operating off a wheel wind deriving power by friction with the trailer tire. The unit is mounted on four 27.00x33 and two 14.00x24 tires on the front axle. The power unit is a 300 hp Cummins engine. Hydraulic power boosts the steering. A straight mechanical drive and friction clutch with 10 speeds is used. Conditions Not Ideal Top performance of the truck can be expected only under the conditions for which it was designed, in particular grades under 5 pct, handling fine material, and dumping where one thin layer can be placed on top of another. The machine will handle 42 tons per haul, operating at high speed, with only seconds used for dumping. On a 2 or 3 pct grade over a one mile haul,

Jan 1, 1952

By C. G. Bruce

"ON NOVEMBER 15th, 1950, the Department of Mines and Technical Surveys announced the discovery of vermiculite near Perth, Ontario. The announcement followed nearly a month of study to determine so far as possible the potentialities of the deposit and quality of the material from surface indications. The mineral was identified by the writer in the field among samples submitted by Mr. Arthur Powers of Stanleyville or, September 22nd, 1950. Within a week of the announcement, mining rights to properties covering a major portion of the deposit had been acquired by commercial interests.Hitherto, Canada has had to import her entire requirements of vermiculite. Prospects of .a domestic supply gave promise of considerable benefit to many industries, particularly the building industry, and to the consumer public. Should the deposit •prove large enough there was also the possibility of exporting to centres in the United States.Field and laboratory studies were continued at the Mines Branch during the winter of 1950-51 as opportunity occurred. It is the purpose of this paper to describe the results of these •preliminary investigations, to attempt to present the Stanleyville occurrence in its proper perspective with regard to similar occurrences elsewhere, and to review the salient features of the vermiculite industry.Properties and UsesVermiculite is a hydrated magnesium aluminum silicate. In appearance it resembles mica, having the same micaceous cleavage, but it differs from that mineral in being very soft, pliable, and inelastic. Colours range from black through dark olive-green and brown to almost colourless."

Jan 1, 1952

By G. Marchand, R. H. Hay, E. C. Pearson

"AbstractA polishing .technique is described together with two anodic etching methods for aluminum and its alloys. Some of the optical and structural characteristics of the film formed by •these etching methods are discussed and it is shown to what degree these properties of the film are related to the crystallographic orientation of the metallic substrate. Applications to the study of recrystallization and twinning phenomena and to the study of plastic deformation, banding, and texture estimation are discussed. Micrographs are shown .to illustrate the manner in which the technique is particularly well suited to the study of such phenomena.IntroductionThe physical metallurgist is constantly faced with the problem of polishing and etching of metallic sections. Mechanical polishing is tedious, time consuming, and not applicable whenever a surface entirely free from plastic deformation is required. Etchants are generally required to reveal the grain structure in order to determine its size, shape, and regularity, or to bring up constituents. In the case of aluminum, the .most common etchant to reveal grains is a mixture of three acids: HC1, HN03, and HF. This etchant is fairly satisfactory on certain alloys and for certain metallurgical conditions but in general fails to give a good definition of the grain on castings, on highly alloyed products, and whenever the grain is smaller than 100 microns in diameter. Besides size and shape, a grain, or crystal, has an orientation and may be endowed with several types of imperfections."

Jan 1, 1952

By Edward H. Robie

MANY engineers currently are working harder than usual, in part because of the demands being made upon them for increased production in the war effort, and in part because engineers are in short supply so that there is more to do for those who are available. In some instances the question has come up as to what additional payment, if any, should properly be made for overtime work, and to what extent is such payment legally permitted under the rules of the Salary Stabilization Board. Most engineers employed in an executive, administrative, or outside salesman capacity are not paid for overtime. They are paid for doing a job instead of for the hours they put in, and are free to do all the unpaid home work they feel they should do after dinner, as well as to do a bit of thinking and worrying during wakeful hours in bed. But engineers employed in a strictly professional capacity normally have standard office hours. Some employers pay for overtime and some don't. Their practice as it existed on Jan. 25, 1951 may be continued. In the absence of such practice at that time, the Salary Stabilization Board says that the engineer may now receive additional compensation up to his straight-time rate for an extended work week. No formal approval of the Board is required. "A professional engineer," in the mind of the Board, "is a person employed in a professional capacity, who, by reason of his special knowledge of the mathematical and physical sciences and the principles and methods of engineering analysis and design, acquired by professional education and practical experience, is qualified to practice engineering." Inducted Engineers A letter from a young man just inducted into the service and fearful that his engineering training is not going to be utilized reached us last week from Fort Riley, Kan. The AIME, cooperating with the other Founder Societies, is doing what it can, through the Engineering Manpower Commission, to see that engineers are not being wasted in the military establishment. So we passed this young man's letter along to T. A. Marshall Jr., executive secretary of that Commission. Mr. Marshall tells us that the normal procedure now being followed by the Army in handling Selective Service inductees is to have them first complete 16 weeks of basic training before assignment to specialized categories. During that time they are classified. If one has an engineering degree he should be classified as scientific and engineering personnel at the end of the basic training period. He should then be transferred to a technical detachment and assigned an MOS (Military Occupational Specialties) reflecting his education. If a young man is looking for a commission, it might be added that the current policy in the Army is to transfer to OCS (Officer Candidate School) applicants for commissions in the infantry only. The local unit commander can give information on this point, based upon the aptitude shown in tests. In view of the current shortage of engineers, it is believed that a young man should seriously consider remaining in enlisted status unless he can obtain a commission in a branch of the service that can make full use of his technical skills. His work may thus be more to his liking even if his uniform is not. New York or Atlantic City? In which place is it preferable to hold the annual meeting of a professional society like the AIME-New York or Atlantic City? That is, a winter meeting. The American Society of Mechanical Engineers has held its recent meetings at Atlantic City, with increasing attendance and satisfaction. The American Institute of Chemical Engineers chose Atlantic City for its recent December annual meeting. Only twice has the AIME ever met in this famous seashore resort: in 1898 and 1904. Chief advantages of going to Atlantic City over New York are that technical sessions are better attended, there being little else to do there in Winter; the cost to members is less, and hotel facilities are better adapted to a large meeting. As to cost, take a banquet, for instance. The Chalfonte-Haddon Hall, which caters especially to winter conventions, charges about $7 for a banquet dinner of standard quality. A similar dinner at the Statler in New York would cost about $8.50, and about $10.50 at the Waldorf-Astoria. (The charge for tickets is somewhat greater than this because of the cost of music, programs, flowers, and other incidentals.) Rooms, too, are somewhat less at Atlantic City, two in a room being accommodated for about $7 per day each, compared with $7 to $10 at a headquarters hotel in New York. On the other hand, AIME headquarters is put to some extra expense for staff travel, food and lodging, and members living in New York and environs are forced to pay a hotel bill. New York, of course, has more varied amusements to offer, plenty of big stores, and the glamour of a big city. The choice may be discussed at the forthcoming meeting in New York. In the meantime if any reader cares to express an opinion one way or the other we shall be glad to hear it. College Scholarships Most parents of children in the later stages of high school find it necessary to give some consideration to the cost of a college education. Although salaries have increased substantially it seems that the cost of the necessities of life, such as food, housing, and maintaining the family automobile, have gone up even more, so the problem of financing the children's education is as acute as ever. Many overlook the possibility of scholarships, or feel that only a student at or near the top of his class has a chance to get one. As a matter of fact, close to 150,000 scholarships and more than 15,000 fellowships, worth some $42,000,000, are available in 1200 American colleges and universities. Those who are interested should send 55¢ to the Superintendent of Documents, Government Printing Office, Washington 25, D. C. for a 248-page publication just issued by the U. S. Office of Education, entitled "Scholarships and Fellowships Available at Institutions of Higher Education."

Jan 1, 1952

By Luiz C. Correa da Silva, Robert F. Mehl

A. D. Le Claire and R. S. Barnes (Atomic Energy Research Establishment, Harwell, Didcot, Berks., England)-—This much awaited paper admirably confirms that the Kirkendall effect is a true diffusion phenomenon and likely to be found in all diffusing systems. The most likely explanation put forward so far to account for the shift of interface is that the two components of the system, diffusing in opposite directions, do so with unequal rates so that there is a net loss of material from that half of the diffusion zone rich in the more rapidly diffusing component. This loss is accompanied, and at least partly compensated for, by a closing up or decrease in volume of this latter half of the diffusion zone and an expansion of the other half so as to tend to keep constant the overall volume per atom. This is manifest as a movement of the original interface. If this is a true picture of what is taking place then there are at least two important matters requiring further study."1—The quantitative relating of the observed shift with the independently measured separate diffusion coefficients of the two diffusing species."2—A detailed study of the mechanism and characteristics of the closing up process."We would like first to make a few remarks pertinent to these topics. In connection with the first of these, it is a pity that more and detailed measurements were not made on the Au-Ag system, the only one for which the separate diffusion coefficients of the two species have been measured.'" One of us (A. D. Le C.) has calculated from Johnson's results the shift to have been expected in samples D.2 and D.3. Darken4 showed that the velocity v with which the markers move is related to the separate diffusion coefficients Dau, Dag, by the eauation:"dN"v = (Dag — Dau "dx"dN"where .is the concentration gradient at the mark-ax"ers. Under certain conditions,4, 20 it can also be shown that:"Xm"v = "2t"where x, is the total marker shift after time, t:"dN". . xm = 2t (Dag — Dau) [9]"dX"Johnson measured Dag and DAu in a chemically homogeneous alloy and so his reported figures represent the true or ideal diffusion coefficients"; the same quantities in eq 9 represent the actual diffusion coefficients as would be measured in the presence of a chemical concentration gradient, so we need to multiply Johnson's reported values of Dag and Dau by the"1 before insert-dlogN "ing them in eq 9. 7 is the activity coefficient of Ag at the concentration prevailing near the markers which we shall assume to be - 50 pct. The values of the thermodynamic factor for N = 0.5 and the temperatures at which D.2 and D.3 were annealed were obtained from thermodynamic data quoted by Darken.' aN/ax was computed from the coefficient of inter-diffusion of Au and Ag given by Johnson on the assumption that in the samples D.2 and D.3, the concentration distance curve could be represented by the standard equation:""No is the original difference in concentration between the two halves of the couple, and + is the error or probability function."aN/ax at x = 0 is then given by:"adN/dx "2/nDt"and we assume that this represents the concentration gradient at the markers, although it is probable that the figure is slightly high."When all the appropriate quantities are inserted in eq 9, we find that the expected shifts are: for D.2, 0.0134 cm and for D.3, 0.0119 cm."The agreement between these results and those

Jan 1, 1952

By William P. Jones

THE consumption of sulphuric acid, one of the most important commodities in our modern industrial world, is often used as a barometer for industrial activity. The economics of acid manufacture are largely dependent upon the location of the place of consumption and the availability of raw materials in that locality. Sulphuric acid is made from SO2 oxygen from the air and water. Therefore the sulphur dioxide is the only raw material to be considered in an economic study. SO2 can be obtained from almost any material containing inorganic sulphur, such as elemental sulphur, pyrites, coal, sour gas and oil, metallurgical gases, waste gases, or gypsum and anhydrite. Many tons of acid can also be reclaimed by the recovery and concentration of spent acids. The aim of this paper is to present a guide to the economic aspects to be considered when the installation of an acid plant is contemplated. It must be remembered that 1 ton of elemental sulphur produces 3 tons of sulphuric acid and that the shipping of sulphuric acid by tank car is very costly. The size of the plant must also be given careful consideration. For instance, operation of a plant producing 5 tons of acid per day might be warranted in Brazil or Pakistan, whereas economics usually favor buying quantities up to 50 tons per day for use within the United States. Elemental sulphur, when available at the low price of 1 ½ ¢ per lb delivered at an acid plant, has always been the raw material most frequently used for sulphuric acid. All conditions favor its use at this price. The so-called sulphur shortage has been the subject of so many technical papers, magazine articles, and newspaper items during the past year that it hardly seems necessary to mention it again, but a very brief review of the matter will serve as a foundation for the discussion that follows. There is no shortage of sulphur. Only a shortage of low-cost Frasch-mined brimstone exists today. Other more expensive sulphur-bearing materials are plentiful, both in the United States and abroad. The low cost of Frasch-mined brimstone has discouraged the development of higher cost sources. However, the approaching depletion of Gulf Coast dome deposits and the greatly increased demand for sulphur here and abroad have made it necessary for industry to prepare for conversion to utilize sulphur in other forms. For future planning this situation must be considered permanent and not temporary. This conclusion is based on the fact that although sulphur demand will continue to rise, the production of Frasch-mined sulphur probably will not increase greatly beyond its present level of about 5,000,000 long tons per year. The International Materials Conference in Washington estimates 1952 requirements of the free world at nearly 7 ½ million long tons; and the Defense Production Administration has recently set a new goal for 8,400,000 long tons annual domestic production by 1955. The total sulphur equivalent produced in this country in 1950 was 6 million tons. What, then, are the alternatives for the manufacture of the vital chemical, sulphuric acid? Today about 85 pct of this country's sulphur, and nearly 50 pct of the world supply, comes from our Gulf Coast salt domes and is extracted from the earth by Frasch's hot water process. The Gulf Coast salt dome deposits have been the most important known natural deposits in the world, producing 90 million tons of sulphur during the past 50 years. However, at the present rate of extraction these deposits cannot be expected to last indefinitely. Pyrites Pyrites are, and have been for many years, the source of more than 50 pct of the world's sulphur requirements. The principal use, of course, is in the manufacture of sulphuric acid. The use of pyrites in the United States has diminished greatly because of the availability of low cost native sulphur, but pyrites have continued a major source of sulphur in many other countries. The most available pyrites for use in this country are in the form of lump pyritic ore and in mill tailings from flotation of other minerals such as lead, zinc, copper, gold, and silver. An important factor, when the use of pyrites for acid manufacture is being considered, is the disposal of calcine. A ton of sulphuric acid requires approximately ¾ ton of high-grade pyrite and results in ½ ton of calcine. If the calcine is a fairly pure oxide, free of harmful impurities, it can be used, after sintering, in an iron blast furnace burden. Its value might be as high as 15¢ per unit of Fe at the blast furnace; or possibly $10.00 per ton of sinter, if it assays 65 pct Fe. This might result in a credit of $4.00 per ton of acid if the sintering plant and blast furnace are both located adjacent to the acid plant. On the other hand, several factors must be considered before this credit can be realized, i.e., freight to blast furnace, availability of sintering facilities, methods of eliminating impurities, and the removal of valuable metal values. In some locations it would be most economical to dump the calcines.

Jan 1, 1952

By J. R. Giegerich

"IntroductionMINING operators in common with other operators are confronted today with two serious problems, shortage of experienced workmen and rising costs. The following review of practices at the Sullivan mine of The Consolidated Mining and Smelting Company of Canada, Limited, outlines certain measures that have been responsible, during recent years, for minimizing the effect of these two problems. The paper is divided into three main sections:( 1) Training programmes and job studies( 2) Improved mechanization and equipment( 3) Large-scale methods of operationTraining Programmes and Job StudiesJob TrainingJob training courses were introduced at Cominco immediately after the last war and proved to be a great benefit to the operations. There were three courses given, Job Instruction Training, Job Safety Training, and .Job Relations Training. These were spread over a period of two years and were taken by all operating supervisors and some key operators.The courses were introduced by a trained instructor from the British Columbia Department of Labour. This man trained twelve of our employees as instructors by giving them an intensive one-week course. Similarity between the three courses was such that the instructors trained in the first one were very readily trained for instruction in the two succeeding courses."

Jan 1, 1952

By E. Swartzman

"IntroductionGENERALLY, the necessity for mining coals of higher impurity content, the drive for lower costs by intensive mine mechanization, changing market requirements, and the increasing competition of oil and natural gas, have continued to result in an upward rise in coal preparation, and have necessitated a more intensive study of coal preparation problems.Increasing adoption of •continuous mining equipment, for example, is introducing new problems in coal preparation. Limited experimental work in the United States (1) shows that the effect of the continuous miner on size distribution varies with the characteristics of the seam. In some seams, the fines problem is lessened, in others it is greatly aggravated. Generally there is a decrease in the relative amount of the top sizes (plus 2 in.) and a substantial increase in the intermediate sizes (down to about 1/8 in.). Contrary to expected results•, where continuous miners with vertical-moving cutting heads are used, an increase in impurities in the slack sizes does not necessarily occur where draw-slate is taken. This is because the draw-slate tends to be kicked out in lump form. However, if a seam contains bands •and lenses of impurities they are bound to be in the mined product."

Jan 1, 1952

"ALTHOUGH Canadian metallurgists have long been active in research, the scope of the work was somewhat limited until the be-ginning -of World War II. The rapid industrial development of Canada during the past ten years has been accompanied by .a similar upsurge in research. However, the wide geographical distribution of the research centres has made it difficult for the individual research workers to meet together and to exchange ideas or even to learn what projects .are being investigated or the nature and extent of the facilities available for work of this kind.The purpose of the present symposium is to assemble data relating to projects under investigation and the facilities employed at the various metallurgical research laboratories in Canada, thus providing some measure of correlation so that workers in different locations may learn what kind of work •is being .done at other points throughout the country.In reporting the symposium it has not been possible to reproduce the papers in full, but excerpts have been selected that give the essentia1 data."

Jan 1, 1952

By J. F. Henderson

"IntroductionTHE National Advisory Committee on Research in the Geological Sciences was set up by the Privy Council of Canada in 1949. It was set up because you, the Geology Division of the Canadian Institute of Mining and Metallurgy, asked that it be set up. The Committee is, therefore, to a consider-able degree, your offspring. In the role of good parents you, of the Geological Division of the C.I.M., should be interested in the progress of your progeny. How is the Committee organized? What has it recommended? What has it accomplished? On behalf of the National Advisory Committee, that is what I want to tell you about this afternoon.HistoryYou will remember that, in 1946, the Geology Division of the C.I.M. set up a Committee on Geological Research. This Committee, under the Chairmanship of Dr. J. E. HAWLEY, found ""that there is no national organization interested in surveying, co-ordinating, and implementing with financial help, fundamental and much needed geological research. Accordingly, the first and most necessary step to put the geological sciences in Canada on a proper footing .is the recommendation that a National Advisory Committee on Research in the Geological Sciences be formed"" (l).This recommendation was endorsed •by the President and Council of the C.I.M. in 1947 and submitted to the Minister of Mines and Resources."

Jan 1, 1952

By W. K. Gummer

"THE LOCATION of Canada's present aluminum industry is determined by availability of hydroelectric power, and ready access to ocean transport facilities. The chief raw material for the production of the metal is imported by ship over several thousand miles of water. In times of freedom of shipping and uncontested movement this provides the industry with its cheapest method of operation. However, during the early part of the last decade the general conditions of ocean and rail transportation were such that interest in the treatment of materials other than bauxite was greatly stimulated. This was the case not only in Canada, of course, but in most other countries.Canada has no deposits of bauxite and much research was carried out on other aluminous materials, chiefly silicates, in an effort to develop more or less economic and feasible methods of treatment. In the United States, this research was considerably more extensive. Some projects were early shown to be of little or no value, whereas others, including the widely publicized lime-sinter and soda-lime-sinter methods, became important. In North America, however, apart from the application of the sinter method to the hitherto waste-product (red mud) of the normal Bayer plant operation, none of these processes contributed appreciably to the production of aluminum during the war. In certain European countries, on the other hand, largely because of their situation with regard to bauxite deposits, they had a more general application, and Germany, for example, produced alumina from clay, ashes, and slag by at least four methods."

Jan 1, 1952

By M. C. McCall

When electric current of any appreciable magnitude flows from a power line into the earth, a change sometimes takes place in the conditions of resistivity immediately surrounding the electrode or medium of contact. If the conducting medium is composed of moist earth or clay the effect is to increase rapidly the resistance. If the conducting medium is coal or a coal bed, the effect is one of slowly decreasing resistance as the coal is carbonized, If, however, the flow of current is not enough to carbonize the coal, it will dry slowly, with a resultant increase in resistance. Measuring ground resistance, or impedance, with conventional commercial ground testers does not always indicate the current that will flow in the earth circuit from a direct-current or an alternating-current power circuit. The exact reason for this has not been determined however, it is thought to be due to the comparatively minute currents used for such testing. A typical ground, tester used by the authors for this work indicated a maximum current of 25 milli-amperes. The frequency of this testing current also has an effect on the readings in all probability. While the possibilities of the effects of varying frequencies has by no means been fully explored in this investigation, there are very definite indications that the impedance of a circuit through a section of earth will vary in some inverse relationship to the frequency of the applied voltages. This is evident at ordinary power-line frequencies ns well as at higher frequencies up to 200 kilocycles, which was the highest frequency available for tests in this investigation. This report is written in the hope that it will stimulate further investigation of the possibilities suggested for communication and the development of safety devices for increased electrical safety in coal mining.

Jan 1, 1952

By Wallace W. Wilson

This DaoerAA calls to attention for the first time, to the writer's knowledge, a purported recovery of oil by substantially horizontal gas cycling that is considerably in excess of 50 per cent of the oil originally in place. The average angle of dip along the path of travel of the gas is less than one degree of arc. The best recovery by gas cycling previously brought to the writer's attention1 occurred in the case of the Mile Six Field in Peru, where about 68 per cent of the original oil in place has so far been recovered. In this case, however. the recovery was greatly aided 1)y the high dip angle of about 17.5". An approximate estimate of recovery was made by the method developed by the writer' for the case of the Cook Ranch Field, using an average relative permeability ratio function dictated by past experience with a number of good quality sandstones. A result of about 40 per cent recovery of the original oil in place wa* obtained after the 8.5 pore volumes of cumulative gas cycling undergone by the Cook Ranch Field. Tile writer desires to emphasize what appears to him as the sound engineering practiced at Cook Ranch, and also the care attending the taking of data and the high quality of the calculations made. It is impossible to take issue on factual grounds with any of the conclusions drawn in the paper. It is, however, desired to point out the difficulty of explaining the unexpectedly favorable oil recovery on ordinary theoretical grounds. It would be of interest to know whether relative permeability ratios have been measured on the Cook sand. The operator is inclined to attribute some of the excess benefit to settling of the oil across the bedding planes into the lower part of the sand. It is difficult for the writer to appreciate the importance of such an effect, inasmuch as the concomitant opening of excessive vacated pore space in the upper part of the sand would he expected to cause excessive bypassing of the gas. REFERENCE 1. Welge. H. J.: "A Simplified Method for Computing Oil Recovery by (Gas or Water Drive." Trans. AIME, (1952), 195, 91. AUTHOR'S REPLY TO MR. WELGE Welge has poined out clearly the difficulty of applying material-balance procedures in calculating the Performance of low-pressure, dispersed gas injection operations. There can be no argument that even with the most favorable assumptions of K,/K,, and with cumulative gas cycling in excess of normal expectations, the calculated oil recovery will be considerably less than the 72.5 per cent recovery realized from this project to Jan. 1, 1951. There probably are at least two reasons for the unusually high recovery from this reservoir, the effects of which would be difficult or impossible to calculate by known methods: 1. The operator did not use the same injection wells for the entire operation, and exercised considerable control over producing GOR by changing the locations of injection wells whenever well performance indicated excessive bypassing. Fifty-six wells were used for injection, not over 29 of which were in use simultaneously. This procedure resulted in frequent shifting of the fluid movement patterns in the reservoir and undoubtedly increased the ultimate recovery. The writer knows of no satisfactory procedure for calculating the effect of this practice. 2. Vertical movement of oil across the bedding planes of the reservoir rock hy gravity drainage tended to maintain a relatively high oil saturation, and hence a favorable K,/K, ratio, in the lower sections of the reservoir. As pointed out by Welge, this condition has aggravated the tendency for high producing GOR, but at the same time it has resulted in increased oil recovery. As may be seen from the performance charts for the various battery areas, operating (GOR'S have been quite high for the last several years of reported history.

Jan 1, 1952

By A. B. Irwin

"Discussion at MeetingDR. D. DERRY (Ventures Limited) referring to the diagram (Figure 15) which shows a transverse structure section across the Central Slocan area, asked what the assumed structure at depth was, remarking that dips are steeper and more uniform at depth and that the contortions with gently-dipping axial planes are at higher elevations. He wondered whether the section represented ,part of a very large fold with steeply-dipping axial plane.MR. J. D. LITTLE (Canadian Exploration, Limited) replied that E. B. Mayo (Kelowna Exploration Company) and others had considered that the entire section illustrated faces to the southwest and represents part of the lower limb of a great overturned •syncline which is concave toward the southwest.DR. R. DEWIT (Geological Survey) remarked that the photograph of a ripple mark (Figure 7) showed internal lamination conformable to the ripple mark and wondered if the structure was not due to slumping during consolidation, since the normal mode of formation of ripple mark would seem to preclude the possibility of such internal stratification.MR. LITTLE remarked that in his opinion such structures should not be depended upon alone with-out other confirmatory evidence of the direction of tops of beds."

Jan 1, 1952

By J. B. Mawdsley

"AbstractThe uraninite-bearing deposits in the Charlebois Lake area of northeastern Saskatchewan are unusual and important concentrations of uranium. They were first discovered in 1949 and preliminary development work to the end of the 1951 field season indicates the probability that this will become •another uranium producing district. The deposits are in zones bordering granite masses. These zones are of migmatite (mixed rocks) composed of calcium-rich meta-sediments intruded and replaced by a fine-grained white pegmatite. Locally this pegmatite is replaced by an end fraction which is relatively rich in fine-grained disseminated uraninite; it is these occurrences that constitute the bodies of economic interest.The fine-grained white pegmatite contains plagioclase feldspar more lime-rich than that in the granites of which it is an end differentiate. This extra lime, evidently derived from the intruded sediments, would result in the raising of the temperature of crystallization of the pegmatite-forming magma, thus consolidating it rapidly near the granite contacts as a fine-grained pegmatite. The end liquor containing uranium was evidently locally concentrated in minor fracture zones in these pegmatites. Where no lime sediments were present. the coarse-grained alkaline pegmatites were formed. Their crystallization would not be accelerated and the uranium would tend not to be localized in the pegmatite but to migrate and consolidate at lower temperatures with the end products, possibly in some instances as pitchblende veins."

Jan 1, 1952

By Edward H. Robie

NEVER before have the annual company reports in the mineral industry field exhibited the typo-graphical art so abundantly as does the current crop. Time was when most company reports made a drab appearance and dry reading, mostly confined to financial data and text that gave little information to the public or technical men. Now, the dollar statistics assume less importance. Considerable information is given on what is going on at the company's plants, new equipment being installed, new methods, properties under development, ore reserves and grades, and similar information of interest to professional men working in the field. We have one suggestion for further improvement: The names of the officers and directors of the company are always given, but only a few companies give the names of the principal operating officials. We think, in the case of a mine for example, that the name of the general manager, his assistant, the mine and mill superintendents, and any other top operating officials who have been largely responsible for the success of operations, are worthy of mention. The reports are now widely read and this recognition is due them. Conspicuous among the annual reports that we happen to have seen, in point of typographical attractiveness, are that of the Texas Co., celebrating its fiftieth anniversary with a gold-plated cover and gold printing inside; and that of Noranda Mines Ltd., with a red and black cover that would attract attention anywhere. Comment on economics, taxes, and labor give an excellent picture of what our industry is facing. Consider the following, from the report of the Union Oil Co. of California:

Jan 1, 1952

By C. M. Signer, W. P. Hewitt

THIS is a story of a mine discovered in the days of the Conquistadores but that remained unimportant until the second decade of this century. Without the usual legendary history of romance and fabulous riches it has become famous for the development of unexpected metals and unusual problems. These developments and experiences, exciting and interesting as any legend, are the substance of the San Antonio mine of the Santa Eulalia district in northern Mexico. Originally opened for its silver-lead content, it developed a tin deposit of singular economic importance and unique geologic interest, a vanadium orebody that for a few years placed it among the leading vanadium producers of the world, and now lead and zinc sulphide ores. It has been the seem of a disastrous flood that brought deep-sea divers into Mexico's desert mountains and raised important problems regarding ground water, demanding unusual measures. Geology and operating questions relating to the above matters will be discussed and much of it is recent history which has become a part of Mexican mining lore. History Dates Back to 1325 Santa Eulalia is the oldest of American cities, founded in 1325 by the Aztecs under the name of Tenochtitlan and devastated in 1521 by Cortes and his rapacious band of iron-willed adventurers. Their lust for gold burned through the Aztec empire and onward into most of North America. Santa Eulalia was in the path of conquest. In 1591 the district's first ore discovery was made near what is now the San Antonio mine. The ores carried no gold and the silver-lead content was unattractive to the early pioneers. Not until 1700 was real mining activity undertaken.

Jan 1, 1952

By W. J. Bennett

"I AM very happy to have this opportunity of speaking to the Montreal Branch of the Canadian Institute of Mining and Metallurgy.I have selected as the subject of my remarks transportation in that area which is at present our only source of uranium -Northwest Canada. Considering the widespread interest in atomic energy, the end-product of uranium, it may be wondered why I have not chosen to speak of a more spectacular aspect of the development. I hope it will be evident from what I have to say that transportation plays a very dominant role in our effort to maintain a continuing supply from Eldorado's producing property at Port Radium on Great Bear lake and from its coming producer at Beaver lodge Lake in Northwest Saskatchewan. Moreover, transportation has such a bearing on the entire mineral development of the Northwest that it cannot help but be of concern to an organization of this kind. Finally, the transportation problem, of which I shall try to tell you something, is quite unique and the story of its solution or partial solution is, I believe, an interesting one.Transportation experience on this continent indicates that the cheapest method of moving freight is still by water -with •rail, highway, and air transportation following, and in that order •of economic significance. Excluding rail transportation, since the area has as yet no railway lines, this order also applies in the Northwest. I shall direct my remarks to the two kinds of transportation which serve our uranium producers -water and air."

Jan 1, 1952

By A. D. Mutch

IT has long been known that there are wide variations in the thermo-electric potential of pyrite. In the last few years a study of this variation and other properties of pyrite was carried out at the University of Toronto by F. G. Smith on specimens of pyrite from many localities.1-3 As a result of these studies the pyrite geothermometer was developed by Professor Smith. The calibration of the pyrite geothermometer is based on the assumption that "crystals of any one electronically conducting mineral species deposited at a high temperature have a more positive thermo-electric potential than crystals deposited at a low temperature, and the thermo-electric potential varies continuously between any given limits of the temperature of deposition." The cause of the variation was postulated to be crystal discontinuities, such as lineage boundaries. As yet this postulated relationship has not been established as fact. On theoretical grounds it is indicated that the thermo-electric potential of pyrite or any other partial conductor is dependent upon a number of factors as well as the temperature of formation. For this and other reasons there is ground for doubt as to the validity of the relationship postulated above. To date a large number of readings have been made with the pyrite geothermometer which have been recorded in terms of the calibration of the instrument in degrees centigrade. So far most of the pyrite tested by this technique has been in association with gold ore. The values for the temperature of formation obtained in these tests appear to be reasonable and, in relation to geological problems, to vary in the right sense. Determinations on some specimens not in association with gold ore have given readings that appear to be much too high, taking into account the probable maximum temperature of the host rock. To sum up, although many determinations made with the. pyrite geothermometer appear to give reasonable values for the temperature of formation of the pyrite, there are at the same time other readings which seem anomalous. On the basis of an examination of available results of work with the pyrite geothermometer, two problems must be considered: 1-the validity of the calibration of the pyrite geothermometer; and 2-the nature of the distribution of the thermo-electric potentials of pyrite in relation to the specific problems that have been examined. In this paper the academic problem relating to the validity of the calibration of the pyrite geothermometer will not be discussed. Instead, the variations of thermo-electric potential of pyrite in association with gold veins will be discussed with regard to specific examinations. The first of these two examinations deals with the distribution of thermo-electric potentials of pyrite in association with a gold vein and was carried out in the McIntyre Porcupine Mine, Schumacher, Ont., in the summer of 1949 as part of a study with this technique. The second problem deals with variations of thermo-electric potential of pyrite in gold ore specimens from all over the world. The specimens used in this study were part of the private collection of Frank Ebbutt, geologist for Howe Sound Exploration Co. Results of Detailed and Reconnaissance Studies In discussion of the results of determinations made in these two studies the values of thermo-electric potential in millivolts will be used. It will be noted that in some of the diagrams the determinations are recorded in terms of pyrite geothermometer temperatures. Fig. 1 is a calibration chart relating, pyrite geothermometer temperatures and thermo-electric potentials. A full discussion of the technique is given in the original paper by F. G. Smith.' Briefly, the determinations are made by placing two stainless steel probes, one hot and the other cold, against the surface of the pyrite crystal being tested. The thermo-electric potential that is developed is read with a null-point potentiometer that is calibrated in what

Jan 1, 1952