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By D. H. Newland

On the bulk basis New York's contribution to the production of oil is small, representing, as it does, a bare half of one per cent of the annual total for the United States. Yet it has more importance than is implied by such a statement. Petroleum includes a variety of organic compounds, some more and some less valuable. It would be a fairer estimate of the situation to say that New York in recent years has produced around 10 to 12 per cent on the average of all Pennsylvania grade oil, the supply of which is strictly limited and the demand steady even in times of overproduction of other grades. One may not infer from this that New York and other Appalachian states enjoy an independent position in the market with a price structure uninfluenced by that of the Mid-Continent, Gulf or California fields. On the other hand, the recent market demoralization in the South and West brought about by uncontrolled production caused prices to drop to a point where the life of the local industry was seriously threatened. The current cost of producing oil in New York under the methods of water-flooding, by which most of the output is now obtained, has been estimated by competent authority at not less than $2.50 a barrel. The

Jan 1, 1934

By E. D. Gardner

About 300 tons of gold ore per week was being produced in February 1934 by Thomas D, Herron and Con Laster from the old lake Superior and Arizona workings; the ground was leased from the Magma Copper Co. The workings adjoined but were not a part of the Magma mine. The lessees had been employees of the Magma Copper Co, at the time the Magma closed down for the summer of 1932. Work on the lease began in July 1932 on an exposure of $2-per-ton ore disclosed in a drift; after a few hand-drilled rounds were blasted the gold content increased to about $30 per ton. Extensive sampling by pannings elsewhere of exposed portions of the vein indicated that other ore shoots existed. The last work previously done in the mine was during the World War, when lessees mined a number of small shoots of copper ore. In some of the stapes the copper miners had left a quartzose streak on the hanging wall that carried $15 per ton of gold. This material did not look as if it cried values and evidently never had been sampled. The first shipment of gold ore was made on September 28, 1932. Up to April 1, 1933, 3,778 tons had been shipped and from September 1, 1933, to January 31, 1934, 3,125 tons.

Jan 1, 1934

By E. A. Anderson, M. L. Fuller

The copper-zinc phase equilibrium diagram has been the subject of many investigations. Until recently, however, the boundary of the terminal solid solution of copper in zinc (eta) has not been thoroughly investigated. This paper reports determinations of the solid solubility of copper in zinc at temperatures from 100' to 400' C., the course of the liquidus and solidus for the eta solid solution and determinations of the peritectic temperature and peritectic point for the reaction between epsilon and the melt to form eta. The liquidus of the eta phase was determined by thermal analysis and the solidus by the microscopical examination of specimens quenched from temperatures above and below the solidus. The temperature of the peritectic horizontal was obtained by thermal analysis and the composition at the peritectic point was determined by extrapolation of the solid solubility boundary of the eta phase to the peritectic horizontal. The solid solubility boundary of the eta solid solution was investigated very carefully. Particular care was used to achieve equilibrium in the alloys at each temperature selected. The X-ray, electrical conductivity and microscopical methods mere used in determining the solid solubility limits. The X-ray method measures the changes in the solvent lattice with increasing solute content and in this manner locates the composition of the alloy at which no further change in the solvent lattice takes place, the limit of solid solubility. The method of electrical conductivity measures the conductivity of the alloys of a graded series of compositions, whereby the solubility limit is indicated by a discontinuity in the conductivity-composition relationship. The microscopical method distinguishes, by direct inspection, between the homogeneous solid solution alloys and those having a secondary constituent in addition to the solid solution phase, and thus indicates from the examination of a series of alloys the solid solubility limit.

Jan 1, 1934

By E. M. Wise

THE practice of adding moderate quantities of nickel to a variety of bronzes has been employed by foundrymen for many years with several objects in view. In some instances it was desired- to harden the alloy; in others it was to increase the fluidity or to improve the solidity of the castings, or to refine their grain. These important matters have been considered in detail by Pilling and Kihlgren1 and by numerous other workers cited by them, and with the exception of the first will not be considered in the present communication. The possibility of reducing the cost of bronze by replacing a portion of the tin with nickel received attention some years ago by Burgess and Woodward,2 and, as will be shown later, offers attractive savings in cost under present conditions. The age-hardening characteristics of the nickel bronzes of appropriate compositions have been known for some time and were mentioned by Price, Grant and Phillips3 and discussed by Wise4 in connection with their paper. These matters are further considered in recent patents,5 and are becoming of commercial importance in the production of high-strength castings.

Jan 1, 1934

By Eugene A. Stephenson, Leon J. Pepperberg

The natural gas industry is essentially a byproduct of the oil industry. When first discovered the gas was usually regarded as a nuisance, and even when found immediately associated with oil, or suspected to be so, it was customary to blow it freely into the air, in the hope that gas would shortly be replaced by a flow of oil. The early methods of production,' transportation, and utilization were neither economical nor efficient; the chief value of gas was based on its use as a fuel, with no regard to (1) its effect. upon the oil with which it was associated, (2) its importance as a lifting agent, or (3) to its possibilities for the manufacture of byproducts. The spread of scientific research among major gas and oil companies, manufacturers, and academic groups, has gradually brought recognition of the fact that many of the technical problems bearing on production, transportation and utilization are common to both the gas and the oil industry. A few of the problems that have received serious study, and from which highly gratifying results have been obtained, are: (1) gas measurement, (2) oil well and gas well capacity tests, (3) elimination of field waste, (4) design of pipe lines and compressor stations, (5) extraction of constituents which might interfere with the normal flow of gas through the line, (6) control of reservoir pressure, (7) estimation of reserves of both oil and gas, (8) control of water encroachment, (9) measurement of factors which influence fluid movement through sands, (10) solubility of gases in oils, (11) effect of dissolved gases upon the properties of the solution. These investigations have demonstrated that almost every problem relating to oil production also involves some phase of natural gas engineering. During the past 15 years the use of experimental methods for the discovery and measurement of obscure, influencing factors, which cannot be determined purely by hydrodynamic or thermodynamic analyses, have contributed much towards the progress made in solving the problems of the oil and gas industries. Most of the experimental work on

Jan 1, 1934

By A. H. Bell

Continued low prices and restricted markets for crude oil discouraged drilling activity in Illinois oil fields during 1933. Only 36 wells were completed in the state, the smallest number since 1904, and of these the majority were scattered wildcat wells, only 10 having been drilled in producing fields (Table 2). Production was curtailed approximately 40 per cent for the first half of the year. During July, August, and the early part of September there was no restriction on production. On Sept. 8, under the "code of fair competition for the petroleum industry," the quota of allowable production for Illinois was fixed at 12,000 bbl. per day. The state's production in 1933 was 9 per cent less than in 1932. What it would have been had there been no curtailment of production and if economic conditions had permitted a normal amount of cleaning out and repairs to wells, it is not possible to estimate, but it would no doubt have been considerably more than the actual figure. No new pools or new producing horizons were discovered in 1933, but the deepening of a Robinson sand well in Crawford County to the McClosky "sand" horizon (St. Genevieve limestone of the Lower Mississippian) resulted in a production of 3 bbl. per day (Fred Patchel, Savilla Shipman No. 5, NE. 1/4, SW. 1/4, sec. 26, T.6N., R.l3W., deepened from 1122 to 1388 ft., to be tested to the McClosky horizon, and, owing to the rapid variations in porosity within short distances, as shown in the Lawrence County field to the south, one test may not be considered as proving or condemning any large area. The average price of Illinois crude oil in 1933, calculated from the posted prices as published in the Oil and Gas Journal and Oil Weekly, was $0.862 per barrel. This compares with a calculated average price of $1.032 in 1932 and 0.852 in 1931. The total value of Illinois crude oil produced in 1933 obtained by multiplying the average price (0.862) by the total production (4,227,000 bbl.) was $3,643,674. Of the 26 wildcat wells drilled in 1933, only one was drilled on known favorable structure. This was the Walmar Oil Company's William Pepple well No. 1, sec. 12, T.4N., R.12W., Hancock County, which tested

Jan 1, 1934

The following paper, submitted by the Russian petroleum authorities, was secured through the courtesy of G. V. Ackerman, Vice President of Amtorg Trading Corporation, and N. V. Vannikoff, Representative in the U.S.A. of the United Oil and Gas Industries of the U.S.S.R. It gives an excellent view of the Russian petroleum industry as seen through Russian eyes. Noteworthy is the tremendous area over which the Russians are searching for petroleum, for this paper refers to such far-flung areas as the Arctic Tamir Peninsula, Kamchatka and Sakhalin on the Pacific, Lake Baikal in Central Siberia, the great new discovery at Neftadag in the plains of West Turkestan, and the oil of the Ferghana oasis, where the derricks look out over to the mosques of Kokand. Of interest also is the new pipe line to supply the industrial centers of Ukraine grouped around the great hydroelectric plant built at Dneprotroy on the falls of the Dnieper. The technical achievements have been noteworthy and we must pause to consider the scope of the undertakings being carried forward. Russia is at the worst a good second to the United States in petroleum reserves and for a long time to come will be a most important factor in the petroleum markets of the world. Her story should be of interest to everyone in the industry. The First Five Year Plan The first Five Year Plan, covering the period 1928-29 to 1932, accomplished the task of transforming the Union of Soviet Socialist Republics from an agricultural, backward land into a powerful independent industrial country, with an advanced technological foundation of its own for finally achieving the social reconstruction of the entire national economy. Along with the gigantic forward 'strides in industry and transportation, radical changes took place in agriculture. The creation of more than 5000 great state farms and of more than 200,000 collective farms serviced by a widespread network of machine-tractor stations has brought the U.S.S.R. to the fore as the largest agricultural country in the world. Imports of tractors and other agricultural machinery in the initial years of the Five Year Plan and the intensive output of this equipment by the great plants of the U.S.S.R. in the latter years of the plan have brought about the mechanization of agriculture in the Soviet Union. This year 250,000 tractors and 30,000 combines will operate in the fields

Jan 1, 1934

By T. L. Joseph

The Bureau of Mines gas been studying the blast furnace for a number of years and has published detailed reports on various phases of its investigations. Inquiries frequently received for information of a more general character than that given in the detailed reports have promoted the preparation of an information circular to cover in a general way the important features of the Bureau of Mines blast-furnace investigations. SHAPE AND DIMENSIONS OF FURNACE The modern blast furnace approximate a refractory-lined steel cylinder about 90 feet in height and 25 feet in diameter. It actually consists of a number of cylinders and truncated cones superimposed upon each other. The shape and dimensions of a modern furnace are shown in figure 1. The bottom section, commonly referred to as the hearth or crucible, is a cylindrical section about 12 feet high. Liquid metal and slag collect in this part of the furnace and are withdrawn at regular intervals; iron is removed at a level about 2 feet above the bottom of the furnace and slag at a level about 5 feet higher. Depending upon on the size of tie furnace, 40,000 to 75,000 cubic feet of preheated air per minute is introduced through from 10 to 16 tuyeres equally spaced around the periphery of the hearth.

Jan 1, 1934

By N. D. Gerald

The mathematical analysis, which is an essential part of this paper, has revealed the interesting fact that contrary to the opinions of many, determinate and measurable economic factors are largely responsible for the price of crude oil. It should, however, be well understood that the results of this analysis are applicable, without qualification, only to the particular period and market studied. There are certain peculiarities of the petroleum industry which make the consideration of its economics very difficult, and at times practically impossible. Noneconomic factors often become highly important and have serious economic effects, which make unqualified predictions based on economic data extremely hazardous and ill advised. However, in spite of the attendant difficulties there are many problems, especially in price analysis, to which approximate solutions must be made for the proper guidance of public and private policy, but their limitations should be kept clearly in mind. An understanding of the nature of prices is of fundamental importance for a number of purposes. Measurement of the motivating factors giving rise to trends and other price movements is essential to forecasting for the intelligent engineering and financial administration of the industry. The fixing of prices, maintenance of an intelligent industrial dictatorship, or the making of other industrial adjustments, demand, for success, an accurate understanding of their probable consequences. The establishment of a system of equitable relations within an industry, or between industries, by methods other than the natural competitive ones, requires a thorough knowledge of the price structures and the nature and trends of the normal and basic prices of their products. This research has shown that in this case, even though the statistical records are only fair, quantitative economics offers a direct and satisfactory approach to the problems of economic consequences dependent on the reactions of mass intelligence. A consideration of commodity prices naturally leads to costs. The true cost of petroleum is so complex and elusive that its accurate deter-

Jan 1, 1934

J. L. CHRISTIE, Chairman T. S. FULLER, Past-chairman W. M. PEIRCE, Vice-chairman W. A. SCHEUCH, Vice-chairman E. M. WISE, Secretary International Nickel Co., Bayonne, N. J. W. M. CORSE, Treasurer Executive Committee H. A. BEDWORTH G. O. HIERS D. K. CRAMPTON R. H. LEACH E. H. DIX, JR. R. F. MEHL J. A. GANN J. WALTER SCOTT' JEROME STRAUSS Finance Committee T. S. FULLER, Chairman W. M. CORSE H. S. RAWDON C. H. MATHEWSON SAM TOUR

Jan 1, 1934

By Charles Ramseyer

THE manufacture of iron and steel is one of the largest of our indus-tries; and in point of size of single plant and equipment certainly the biggest of all industries. By the general public it is generally con-sidered a prime example both of the marvelous technical advances achieved by modern science and engineering in the design and operation of equipment and of the efficiency of big business in the coordination of men and materials. Actually the operation of its basic processes has not changed significantly in either theory or fundamental design of equipment in the past 75 years. Though many other process indus-tries have been born and developed, and not seldom completely revolu-tionized, during this period, the primary processes of making iron and steel are still carried out along the lines laid down, and in the equipment originated so long ago, by Bessemer, Siemens and Martin, and subse-quently expanded to practically the modern scale by Carnegie, Schwab and Captain Bill Jones in the eighteen eighties and nineties. The application of the principles underlying the continuous counter-current physical and chemical interaction of solids, liquids and gases, which have been so successfully used in the rapid evolution of our chemical process industries, has been very largely lacking in the steel industry. In the days of -the last-named giants, especially Carnegie, the steel industry made great and rapid technical progress. Carnegie's ever driving idea (as later with Ford in the production of automobiles) was the finding of new and better ways of making cheaper steel. Carnegie himself was a steelman, and so long as he dominated the industry its technical progress. was rapid; and he, like Ford, was vastly successful financially as well, since his costs were continually being driven lower than those of his competitors by his advances in steelmaking technique.

Jan 1, 1934

By Mehl, Robert F.

IT has been shown by numerous studies that the orientations of new metal crystals are determined by the orientations of the crystals in the original matrix, whether these new crystals are formed by recrystalliza-tion, by precipitation from solid solutions, or by transitions in the solid state. The orientations of crystals formed by recrystallization of cold-worked worked metals that bear preferred orientations are occasionally simply related to the initial preferred orientation; often, however, the relation-ship is not simple, but complicated and obscure in origin.1 The orientations of crystals formed by precipitation from solid solu-tions have been shown by many studies in this and other countries to be determined by the orientation of the crystals of the solid solution stable at the higher temperatures, though here again complicated cases have been found and no general theory is available .2 Related to this latter class

Jan 1, 1934

By E. M. Wise

PLATINUM and palladium are the most generally useful, most ductile and least rare members of the platinum family. They have many impor-tant applications in the pure state but for other applications it is fre-quently desirable to harden them and otherwise modify their properties by alloying small amounts of the other platinum group metals with them. These alloys are frequently required to withstand very drastic forming operations and to possess certain mechanical properties to fulfill specific requirements. For these reasons a knowledge of the tensile properties and annealing characteristics of pure platinum and palladium as well as their more useful commercial alloys is important to the user, and the fabricator. The present work was undertaken to fill this need. Rather brief (5 min.) annealing treatments were employed to render the data of maximum practical value and all tests were conducted upon 0.050-in. dia. wire, initially reduced 50 per cent in area by cold drawing, for the same reason. CONCLUSIONS 1. Pure (thermocouple grade) platinum reduced 50 per cent by cold drawing exhibits the following tensile properties: ultimate tensile strength, 36,000 lb. per sq. in.; proportional limit, 27,000 lb. per sq. in.; elongation, 2.5 per cent in 2 in.; reduction in area, 95 per cent. When fully annealed by treatment at 1100°C. its properties are: ultimate tensile strength, 20,700 lb. per sq. in.; elongation, 30 per cent in 2 in.; reduction in area, 93 per cent.

Jan 1, 1934

By H. I. Althulee

The mines operated by the Compañía de Real del Monte y Pachuca, Pachuca, Mexico, are in two districts, the Pachuca, and Real del Monte. The principal area of mineralization is within a rectangle roughly 10 miles from east to west and 6 miles from north to south. It contains a number of veins from 2 to 20 ft. wide, which are exploited by this mining company. The scattered position of the producing mines led to the construction of two mills between 1906 and 1908; the Loreto mill, in Pachuca, averaged 2600 tons daily, and the Guerrero mill, in Real del Monte, milled 1270 tons daily. On Feb. 1, 1929, the management decided to enlarge the Loreto mill to take the combined tonnage of both mills at that time. This economic measure required the centralization of ore delivery, which would also afford a material saving in the cost of ore transport. The centralization would give the company the following advantages over the former system of operation: 1. Beneficiation at a single mill, closer to source of materials and supplies than the abandoned Guerrero mill. The refinery is also in the Loreto patio. 2. Ore delivery to surface at one point (San Juan Pachuca shaft) instead of at four. 3. Elimination of aerial tramways. To show what would be required to effect this centralization, it is necessary to describe the means by which the ore was delivered to the two mills, prior to centralization. The heart of the Real del Monte district is roughly four miles from that of the Pachuca section. The producing mines in these two districts were: Pachuca district: Real del Monte district: Santa Ana mine La Rica group Camelia group Purisima group Santa Margarita mine

Jan 1, 1934

By Harold H. Goe, Louis V. Bender

The recovery of arsenic was started at the Washoe Reduction Works (later called the Anaconda Reduction Works) in 1904, when an arsenic plant was constructed adjacent to the lower end of the 60-ft. main flue.' This plant originally consisted of a Brunton roasting furnace for treatment of flue dust and a small reverberatory furnace for treating the crude arsenic produced in the roasting operations, together with the necessary kitchens for condensation of the fumes and grinding and barreling apparatus for preparing the refined white arsenic for market. The Brunton furnace was fired with wood. It was 14 ft. 6 in. in diameter with two outside fireboxes. The hearth revolved upon a central shaft. The charge was fed through a dust-tight hopper on to the center of the hearth and slowly moved to the outer edge of three rows of stationary rabbles fastened in the roof of the furnace. There was a 3-ft. space between the hearth and roof. A crude arsenic was condensed from this furnace. The hot flame from the fireboxes passed directly over the charge, vaporizing the As203 that was carried through brick flues to the condensing chamber. This chamber was 8 ft. high, 16 ft. wide and 240 ft. long, divided into small kitchens by partitions spaced every 7 ft. It was connected with the main flue system to provide draft and to receive any losses from the chamber. The small kitchens were connected by openings in such a way that the fumes took a zigzag course, causing them to come in contact with the cold walls and ceiling and condense the arsenic. There was an opening from the outside into each kitchen, for the removal of the deposited arsenic, which was closed by a wooden door. The refining furnace was a small coke-fired reverberatory having a hearth 10 by 20 ft. in dimensions. It had three hoppers through which the crude charge was introduced, and one firebox placed at one end. The hot gas from the burning coke passed over the charge, volatilizing the arsenic and carrying it to the kitchens.

Jan 1, 1934

By Peter Price

Introduction The Horne mine, the property of Noranda Mines, Limited, has in the last six years become one of Canada's leading gold and copper producers. Since the smelter was blown-in during December, 1927, up to the end of 1933, it has produced approximately 1,200,000 oz. of gold and 35O,OOO,OOO lb. of copper. The property is situated within an area occupied entirely by pre-Cambrian rocks and characterized by the complexity of rock types and structures common in such terrain. But apart from this the mine also presents other features of unusual interest in the size, number, and variety of the ore-bodies, the mineralogical associations, and the rather exceptional values both in gold and copper. It is not surprising, therefore, that a study of the geology of the mine should bring to light many interesting problems. The present paper summarizes, as concisely as possible, the results of such a study. Actually, it is a much abridged version of a more comprehensive and detailed paper completed by the writer a year ago (1), but embodying certain corrections and additional data made possible as a result of further development at the mine and of field work carried out during the summer of 1933. Owing to limitations of space, the paper is, in the main, a presentation of conclusions arrived at in the course of the study. Much of the supporting evidence cited in the thesis referred to has, of necessity, been omitted here.

Jan 1, 1934

By Paul F. Grundy

The ever changing conditions in the coal-mining industry and the increasing competition of other fuels such as oil, natural gas, wood refuse, etc., have made it imperative that the coal operator be in a position to supply a constantly uniform and clean product. The old idea of putting on the market "anything so long as it's black" no longer holds good. Today's users of fuel have to consider the amount of heat per dollar they obtain from the fuel they buy. Burning of coal has become largely mechanical, at least so far as industrial coal is concerned, and industrial coal is the kind the bituminous operator is for the most part called upon to supply. When we get into things mechanical, the matter of precision has a mighty bearing on efficiency. Precision in coal means standardization of quality, or uniformity of preparation in size and also in ash and moisture content. The trend of coal mining is ever towards more and more mechanization. Mechanization means coal-cutting machinery, loading machinery, conveying machinery, etc. Although such methods cut the cost, the cleanliness of coal so mined and loaded is not controllable to the same extent as when each operation is by hand labour. The operator has therefore the problem of mining his coal as cheaply as possible, but at the same time preparing a product which will to the utmost satisfy his customer. The answer is a mechanical cleaning plant. Before installing a cleaning plant, however, the operator must take into consideration the cleansability of the coal from his particular mine. This is accomplished by taking representative samples of the seam or seams to be treated, and subjecting these to screen tests, followed by float and sink tests on each size product. From these tests, it can be readily found to what degree of cleanliness the several sizes can be prepared advantageously, and also what will be the percentage recovery of cleaned coal. The accompanying tables give the results of representative tests on Michel coals of minus-2-inch size. All coal over 2-inc.h was intended to be hand cleaned. The coal-cleaning plants in general use at the present time come under two broad classifications, namely, wet and dry.

Jan 1, 1934

By T. C. Campbell

Copper is extracted from the Chuquicamata oxide ore by a hydro-metallurgical process. The ore is crushed to 3/8-in. sizing, and leached with a sulfuric acid electrolyte. Chlorine is precipitated. and the ferric iron reduced in the enriched electrolyte, after which the copper is recovered by electrolysis with insoluble Chilex and lead-antimony anodes, the spent electrolyte being returned to leaching. Cathodes are melted and refined in market furnaces and cast into commercial wire-bar and cake shapes. Sulfuric acid for the process is supplied by the brochantite in the ore. Water for washing the ore is advanced through the solution system and finally after cutting by electrolysis to from 6 to 16.0 grams per liter is completely stripped by the cuprous chloride method and run to waste. The cuprous chloride so obtained plus that resulting from precipitation of chlorine from strong solution is dissolved in ferrous chloride brine and the copper cemented on scrap iron. The cement so obtained is in part used to reduce ferric iron in electrolyte, and as it is of exceptional purity is also furnace refined and cast into an exceptional quality of fire-refined copper. Fig. 1 is flow sheet of the operation. The reduction plant is composed of seven divisions as follows: (1) crushing, (2) leaching, (3) tailings disposal, (4) dechloridizing, (5) sulfur dioxide treatment, (6) electrolytic tank house, (7) smelting and melting. A brief description of each of these divisions will be given. Crushing Ore that is frequently blocky and up to 5 ft. in section is crushed in four stages to 3/8-in. mesh. The first stage of crushing is called primary and the next three stages are known as secondary crushing. The first stage is accomplished with two 60-in. Superior McCully gyratory breakers by which the ore is broken to 9 in. The second coarse gyratory breakers crush the ore to 3-in. sizing. There are seven No. 10 McCully gyratories in this service, for one of which recently has been substituted a No. 7 cone crusher. The third and fourth stages of crushing are accomplished by fifty 48-in. disk crushers. In the third stage 14 disk crushers break the ore to 1 in., and in the last stage 36 disk crushers turn out the final product of 0.371-in. sizing. Reference to the flow sheets of Figs. 2 and 3

Jan 1, 1934

By Thomas M. Price

Sand production for use in hydraulic concrete is probably the most important element affecting the physical characteristics of the resulting concrete in the opinion of most engineers, aggregate producers and contractors of today, who are engaged in the effort to produce stronger concrete per unit of cement used. Their opinion is based on both laboratory and field results. In the past, proper cement production has been the object of most of the study given this subject and while it is still studied by the extensive and well equipped laboratories that are a part of every cement mill, as well as by all governmental laboratories, at the present time the object of most of these studies has been in the field of low heat and quick setting qualities rather than the effect on the strength of the concrete. It is recognized that concrete must have two important qualities; namely, workability with the least water possible, and uniformity. These qualities have been accepted as axiomatic and possible to obtain if the foreman in charge knew his business. Now, however, with concrete produced by plants that mechanically weigh and chart all the ingredients, including water, of a batch of concrete, the foreman cannot cut and fit his aggregates, cement and water to fit his own desires and the secret of the important qualities of workability and uniformity are found to lie largely in the sand, hence the attention given its production at the present time. With this condition in mind the engineers of the United States Bureau of Reclamation and the Six Companies Incorporated in designing the plant for producing the aggregates for the Boulder Canyon Project included every possible means for the production of a sand of a constant and acceptable fineness modulus as well as a constant moisture content, and for attaining these results with as few detrimental ingredients, like silt and vegetable matter, as possible. This aggregate plant (Figs. 1 and 2) is in Hemenway Wash, 7 miles north of Boulder City. It is 4 miles upstream from the low-level mixing plant. At this screening plant 8,234,000 tons of raw aggregate are being

Jan 1, 1934

By Chas. F. Jackson

During the past 5 years the Bureau of Mines has published information circulars dealing with mining methods and costs at 78 ore mines; 7 circulars, each of which is devoted to a discussion of one of the principal mining, methods; and 23 circulars dealing with special phases of mining, such as ventilation, shaft sinking, tunnel driving, the cost of equipping and developing prospects and small mines, underground transportation, diamond drilling, and ground support. These circulars were written by many different authors, and in order that the method of presentation and the basis for compilation of data might be the same in all the papers the Bureau drafted an outline to be followed in their preparation. To clarify the data in these circulars, which are in the libraries of many engineers and mining companies, and the summarized data presented in this paper, that portion of the outline dealing with cost and labor-performance data is reproduced below.

Jan 1, 1934