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By W. J. PRIESTLEY

WHEN during the war the Navy Department decided to build an armor-plate and gun-forging plant of its own at South Charleston, W. Va., one of the most important units of the equipment proposed was a 14,000 gross ton forging-press to be used for forging, bending, and rectifying battleship armor-plate and making hol¬low forgings for large caliber guns. A press suitable for doing this kind of work was put into operation in the fall of 1921 and was operated successfully on armor-plate and large forgings until the closing down of the ordnance plant following the Limitation of Armament Conference held in Washington, February, 1922. PURPOSE OF THE PRESS There are three methods by which armor-plate can be made, namely, hammering, forging, and rolling the ingot. Each method produces a different result in the mechanical working of the steel. The hammer was eliminated as impractical from an operating standpoint. The first armor-plate made in this country was worked under a hammer at the Bethlehem Steel Co., between the years 1891 and 1893, but was superseded by forging when the large press was completed in 1893. Harry T. Morris of the Bethlehem Steel Co. informs me that the 1.25-ton steam hammer began operations in 1891 and was in operation for about two years. The Carnegie Steel Co. and the Midvale Steel and Ordnance Steel Co. also forged armor-plate. Certain European manufacturers rolled the plates from large slab ingots, after removing the sink-head and giving the body of the ingot a light pass under a hydraulic press. While rolling accomplished more mechanical work on the surface of an armor plate, forging, on the other hand, resulted in a greater amount of work in the interior of the plate. Either type of equipment involved an enormous expendi¬ture, so it was deemed advisable to adopt the method which would make it possible to use the equipment for more than one purpose. Since g large rolling-mill could be used only for the single operation of rolling armor-plate, a press was decided on, for the reason that it might be designed so as to forge armor, as well as bend and rectify it, and also be used in the forging of ingots for large caliber guns, both in the form of hollow forgings and also solid shafts.

Jan 1, 1926

By R. R. Harvey

Recent evidence has indicated that the films forming at crude oil-water interfaces are the result of naturally occurring su,rface-active components in the crude oil rather than oxidation products resulting from exposure of the oil to air. Since the presence of such films may strongly affect the displacement of oil from porous media, a knowledge of their composition and formatiorz is of fundamental importance. In this study, without the assumption of a specific mechanism, film formation is considered to involve the transfer of a weakly surface-active species in solution in the oil to the oil-water interface. The film gas law and the Gibbs adsorption equation may thus he applied to the system. The rigid films which form upon decrease of the oil-water interfacial area are considered a result of the very slow rate of re-solution of the film material into the oil. When the shrinkage of the interface is very rapid, the amount of film material leaving the interface is negligible, and the system may then be treated in the same manner as an insoluble film. The combination of these treatments leads to a new concept of the film factor in which it may he quantitatively related to the concentration of film-forming material at the interface. Suitable experiments can then yield the following information. 1. Original concentration of surface-active species in the oil. 2. The change of concentration with time. 3. Concentration of surface active species at the interface. 4. The change of this concentration with time. 5. Interfacial tension of the system at any time and its variation with time. 6. Equilibriunz concentrations for a given set of conditions. 7. Concentration requirements for solid film formation. 8. Molecular diameter of the adrorbed species. These calculations may be made solely from data taken from measurements on the original oil. While using the pendant drop method of interfacial tension measurement of crude oil-water systems, Bartell and Niederhauser' remarked on the thin, transparent, pliable, solid films or membranes which were often formed at the interface between crude oil and water. As a result of their observations of these films, Bar-tell and Niederhauser concluded: 1. The films are formed by material from the oil adsorbed at the interface rather than by a reaction at the interface. 2. The adsorption of the film-forming material is a rather slow process. 3. There are good indications that the process is reversible; i.e., the film constituents may re-dissolve into the oil. 4. The film will spontaneously spread over any new surface formed. 5. The process of adsorption at the interface is accompanied by a decrease in the interfacial tension of the system. Although they had proved that film formation was not due to a reaction at the interface, Bartell and Niederhauser were unable to demonstrate conclusively whether these film-forming constituents were present in the original reservoir oil or whether they were formed as oxidation products after exposure of the oil to air. Recent evidence seems to point to their presence in the original oil. Although the true nature of the film-forming constituents is still uncertain, these conditions would be fulfilled by the assumption of the presence of a slightly soluble surface-active component in the original oil. This component would migrate to a freshly formed interface because it would thereby lower the free energy of the system. The component at the surface constitutes an expanded monolayer which would become compressed, upon retraction of drop, due to the slow rate of re-solution of the film components into the bulk of the oil. It is possible, by involved extraction processes, to separate or at least concentrate this film-forming fraction. However, using the assumptions made above, the technique of monolayer film study may be applied to reveal much of the nature of the adsorbing material without resorting to an actual separation of the film-forming constituents.

By Herbert Hoover

YOUR committee asks that I speak today on the relations of the engineering profession to public affairs. That takes in a lot of ground. This being a cheerful occasion, I will assume that I should exclude the engineer's function as a taxpayer. This being a nonpartisan occasion, I will assume that I should not refer to his voting emotions in 1940. Perhaps what was in the minds of your committee was the application of engineering thought to the confusions of the times. That is also a lot of ground. I fear, however, its boundaries disappear in mirages and rainbows on all sides. Now any entry of the engineer into public affairs involves his breaking into the fields of the sociologists, the economists, and the politicians. However I don't know why, seeing the difficulties these professions are having, they should not welcome a little help.

Jan 1, 1939

By E. H. Erwin Gartner

The Rhenish lignite deposit in the Nordrhein-Westphalia province of the German Federal Republic covers an area on the left bank of the Rhine River of about 970 sq miles (Fig. 1). Here, in the Miocene era, some 20 million years ago a lignite seam was formed and later broken, through tectonic movements into several blocks, some thrown down into depths of over 1,500 ft. This deposit consists of a single seam, in places up to 300 ft thick, but averaging about 150 ft. In a few areas, it is split into as many as five seams, separated by barren strata. It contains about 60 billion tons (2000 lb/short ton) of lignite which, however, being relatively young geologically, has, because of approximately 60% moisture, 2 to 8% ash, and low sulfur, a net calorific value of 3,340 Btu. That calorific value increases, however, with rising thickness of the cap rock. About one-third of the yearly production of 90 to 100 million tons of raw lignites is converted into briquets. Raw lignite is pulverized and dried to about 18% water content and then pressed without binder into briquets under a pressure of about 14,000 psi. The briquets are being used primarily for residential heating; their sales, however, have been declining sharply since 1963. On the other hand, the volume of raw lignite used in steam power plants has been rising steadily and amounts at present (1968) to about two-thirds of the total production. Huge steam power plants, such as Frimmersdorf, shown in Fig. 2 (which, with an installed capacity of 2,600 MW [megawatt], represents the world's largest steam power plant) with a generating capacity of up to 300 MW per unit and a total installed capacity of over 6,000 MW, contribute about 26% of the total electric power production of the German Federal Republic.

Jan 1, 1969

By S. C. Lindsay, D. J. I. Evans

With each year that passes hydrometallurgical processes are being more widely used to recover base metals from ores and concentrates. Generally these processes involve liquid-solid separation of metal-bearing liquors from barren residues. This may be done by countercurrent decantation, thickening and filtration, or filtration or centrifuging only. Choice of method is governed by chemical and physical characteristics of the pulps; cost of labor, power, materials, and waste disposal; and even by the amount of capital available when building plans are under way. Since all these controlling factors change with time and location and with technological advances, the separation method must be re-evaluated when new plants or expansion programs are contemplated. At the Sherritt Gordon refinery in Fort Saskatchewan, Alberta, an ammonia pressure leaching process recovers nickel, copper, and cobalt from the nickel concentrate produced at Lynn Lake, Manitoba.' Pregnant liquors are separated from the barren leach residues in a thickener-filter liquid-solids circuit. The decision to use this type of separation was based on a summation of economic factors during the pilot plant and design stages. Although countercurrent decantation was not incorporated in the refinery flowsheet, the problems solved in thickening the leach residues and the experience gained in operating the commercial plant are pertinent to countercurrent decantation, particularly where it is applied to slow-settling leach slurries or slurries having a relatively high vapor pressure of a valuable, obnoxious, or poisonous vapor. The nickel sulfide concentrate is leached under pressure with air and ammonia to dissolve the nickel, copper, and cobalt and most of the sulfur, leaving a residue of iron and siliceous material to be discarded.2,3 During a subsequent distillation stage to recirculate part of the ammonia used for leaching, copper is recovered from the solution as a high-grade sulfide. After further purification to remove traces of copper and undesirable sulfur compounds, the nickel is precipitated by hydrogen under pressure at an elevated temperature. The cobalt, together with unreduced nickel, is precipitated as a mixed metal sulfide by hydrogen sulfide for eventual cobalt recovery. The end solution is then evaporated to produce a crystalline ammonium sulfate byproduct. As shown in Fig. 1, the nickel concentrate is leached in a continuous, two-stage, countercurrent circuit. In the first stage, or adjustment leach, the fresh concentrate is partially leached (60 pct) in the liquor produced in the second stage, or final leach. This system is necessary to produce a solution suitable for treatment in the copper sulfide precipitation step. Both stages are carried out at 170" to 180°F under a total pressure, with air, of 100 to 120 psig in large, horizontal, water-cooled autoclaves. The autoclaves are divided by overflow weirs into four compartments to give a certain amount of staging during leaching. In each compartment a relatively slow-speed (100 to 150 rpm) agitator maintains the nickel concentrate in suspension. Adjustment leaching, carried out in two autoclaves in parallel, is followed by a thickener-filter liquid-solids separation. Final leaching is done in two parallel trains of three autoclaves using aqueous ammonia to extract metal values from the adjustment leach residues. This too is followed by a thickener-filter circuit. Here the residues are repulped once with aqueous ammonia and twice with process water and refiltered after each repulping stage, to insure a maximum recovery of soluble metal, before being discarded to the tailings pond. The adjustment leach is followed by a seven-disk Dorr-Oliver American filter, with an agitator in the filter boot to keep the residues in suspension. Agitators have also been installed beneath the four ten-disk filters following the final leach thickener. Slurry Characteristics: A typical analysis of the Lynn Lake nickel concentrate, produced by differential flotation,' is given in Table I. The concentrate comprises 35 to 49 pct pentlandite, (Fe, Ni)S; 3 to 6 pct chalcopyrite, CuFeS,; 1 to 4 pct pyrite, FeS2; and 24 to 42 pct pyrrhotite, Fe1-2S (where x varies between 0 and 0.2) together with various siliceous minerals such as actinolite, hornblende, and talc. During leaching, the sulfur in the pentlandite, chalcopyrite, and part of the pyrrhotite is successively oxidized through the thiosulfate and poly-thionate radicals to sulfate and sulfamate." Simultaneously the nickel, copper, and cobalt are converted to soluble ammine complexes and the iron in the pentlandite, chalcopyrite, and part of the pyrrhotite is oxidized to a spongy hydrated iron oxide. The hydrated iron oxide is readily broken down by the agitation needed to sustain the concentrate in suspension and to maintain a satisfactory mass transfer of the oxygen from the air to the slurry. Table I shows typical chemical, screen, and

Jan 1, 1961

By W. V. Vietti, E. P. Hayes

OpeRations on the Texas Gulf Coast during 1936 increased materially over 1935. A number of new fields were discovered and a few of the older fields were extended, both by the discovery of deeper pay sands and by lateral expansion of the known producing horizons. Twenty-seven new fields have been discovered, of which 25 are oil fields and the others are gas fields that have every indication of becoming oil-producing areas. Amelia, Anahuac, Bay City, North Pettus, Placedo, Pickett Ridge and Tomoconnor have had major extensions. Production for 1936 amounted to 91,224,844 bbl., an increase of 21,627,033 bbl., or 31 per cent, over the 1935 production of 69,597,811 bbl. The number of producing wells at the end of 1936 was 6727, as compared with 4851 at the end of 1935. Proration has continued in force, thus decreasing the rate of depletion and the number of abandonments normally expected. New Fields A brief discussion of the new fields follows, in addition to Tables 1 and 2, which contain the general data on these fields. Aransas (McCampbell).-Buckingham and McCampbell No. 1 McCampbell was drilled to 7501 ft., then plugged back to 6560 ft. and completed in the Marginulina for a 100-bbl. flowing well on July 18. Bee County.—The Voss field, discovered by Swiger and Devonian's No. 1 Voss, and the Holzmark field, discovered by Miller and Donzis on the Holzmark farm, are both of the same type structurally and are caused by folding against a fault, one field being on one side of a fault and the other on the opposite side of the same fault. Brooks County.—-Standard Oil Company of Texas Garcia No. 1, the discovery well in the Alta Mew field, and Dick Young's Singer No. 1, the discovery well of Alta Verde, appear to indicate small fields. Garcia No. 1 was drilled to 8022 ft. and plugged back to 2485 ft., at which depth the well made 189 barrels. Lockridge.—This gas field was discovered by Gulf Production Company's Fairfield No. 1, in Brazoria County. It was originally drilled to

Jan 1, 1937

By Louis D. Huntoon

(New Haven Meeting, February, 1909.) THE Hammond Mining and Metallurgical Laboratory is the gift of Prof. John Hays Hammond to the Sheffield Scientific School of Yale University. Professor Hammond was graduated from this school in the class of 1876, and has always shown great interest in its welfare and progress. In 1903, he offered to build and equip for it a mining and metallurgical laboratory. This offer was gratefully accepted by the trustees; and in October of the same year the architect, W. Gedney Beatty, and the writer were employed to draw up plans for the building, which is the largest of its kind in this country. The Treasurer's report shows the total gift of Professor Hammond, including land, building, and equipment, to have been $128,741.53. This does not include $5,000 given by Professor Hammond to defray incidental expenses. The detailed cost of the machinery and installation, included in the above sum, is as follows: Machinery, $9,846.00 Pipe and fittings, 925.05 Hangers, shafting, pulleys, belts, etc., . 357.83 Steel-work, tanks, launders, etc., . 272.19 Screens for sizing ore, 411.37 Lumber, 1,896.36 General Supplies Hardware, . $135.96 Tools, 263.66 Paints, . 04.63 Electric and incidental, . 439.57 - 1,043.82 Machine-shop material, 259.44 Labor, 722.29 - 981.73

Mar 1, 1909

The 118th meeting of the Institute was under the auspices of the Institute of Metals Division and the Iron and Steel Section, and was held at Milwaukee, Wis. The opening session was a joint meeting with the American Foundrymen's Association and the American Malleable Castings Association, and was presided over by Benjamin D. Fuller, President of the American Foundrymen's Association. At this time Hon. Emanuel

Jan 12, 1918

Jan 1, 1915

By AIME AIME

FREE competition, long the controlling ideal of domestic trade within the United States, has had the fundamental geographical advantage of functioning in the world's largest area of unrestricted commerce. Goods moved back and forth across state lines, unimpeded by customs, and industrial operations have developed rapidly to meet the expanding needs of a pioneer country richly endowed with natural resources. Fifty years ago, antitrust laws were adopted to protect the competitive private enterprise principle. It became illegal for one person to combine with another to restrain trade or commerce among the several states or with foreign nations. The original legislative measures defining this philosophy were the Sherman Act of 1890 and the Clay- ton Act passed in 1914. The development of Europe and other parts of the world was influenced by different conditions which led to a different theory of trade. Here were many small nations, with limited natural resources and a thin market, and they attempted to protect their national economy by tariff walls. International business arrangements for the purpose of diminishing the ups and downs of the more competitive system --crux of the modern cartel operations-seemed a logical device to stabilize production and guard the interests of both workers and consumers. European governments as well as European industrial interests became convinced that if com- petition could be held in bounds the danger of business depressions and un- employment could be reduced.

Jan 1, 1944

By John Wellington Finch

WHAT is an engineering opportunity? To the mining .engineer the natural assumption is that the first requisite 'is a mineral deposit, but, of course, it is not so simple as that. There are at various points on the earth really very great mineral deposits which, on account of geographic location, backwardness of the country, or hostility of its natives, are now, and for a long time to come will be, quite valueless. The mining engineer, and for that matter the civil engineer, is more dependent upon the decisions of capital than upon any other factor in his profession. Ordinarily it is to be assumed that money will go to any place where it is clear that an adequate return upon its investment can be secured, but for many years it has not been safe to depend upon this. ' As already stated, there are many places where local conditions are such that mining is not safe to engage in and there are still other places in which conditions have been so aggravated by the Great War and by the social unrest which has upset the Asiatic region that capital is naturally most reluctant to venture, even when engineering data makes the undertaking appear attractive. It will be evident, I. believe, that there are many factors vital to the success of a mining enterprise in some of the remote countries which we do not have to consider in the United States and which do not, in fact, exist here.

Jan 1, 1924

By Arthur R. Still, Paul Gilmour

The ore deposit of the Iron King mine occurs in a group of steeply-dipping metamorphosed eugeosynclinal volcanic and sedimentary rocks of Precambrian age. Within this sequence, the ore deposit lies at the contact of a unit made up of rhyolitic tuff and interbedded andesite and a structurally underlying series consisting of andesitic tuffs, minor rhyolitic tuffs, and argillaceous sediments. Field evidence suggests that these rocks have been overturned. The ore deposit is made up of a series of overlapping, conformable or bodies consisting of massive pyrite and associated lenses of massive quartz. These contain recoverable amounts of gold, silver, lead, zinc, and copper. A parallel zone of copper mineralization occurs within the hanging-wall rocks. The deposit is considered to belong to a large and important group characterized by mineralogical composition and the lithology and structural type of the host rocks. Evidence regarding the origin of the deposit is reviewed, and it is concluded that the ore bodies were formed through the agency of volcanic hot springs on, or near, a submarine surface of deposition

Jan 1, 1968

By H. H. Richardson, E. H. Dix

Of all the alloying elements used in commercial aluminum alloys, copper stands out as by far the most important, and it is perhaps for this reason that the constitution of the aluminum-copper system has received the attention of a number of experimenters covering a period of approximately 20 years. It would be expected that during this time the equilibrium relations would have been thoroughly and exactly worked out. In a general way this is true, but there is a surprising lack of agreement in the details of the high aluminum end of the diagram, particularly in regard to the solid solubility of copper in aluminum, which has been given variously as 2 per cent. to 5 per cent. at the eutectic temperature. The importance of this is much greater than might at first appear to one unfamiliar with modern commercial aluminum alloys. This is true because, with one exception, the susceptibility of the strong alloys to heat treatment depends, in part at least, upon the solid solubility relations of copper in aluminum. In 1919, Merica, Waltenberg, and Freeman1 published the first detailed information on these solubility relations. They found that the solubility of copper decreases with falling temperature from about 4 per cent. at 525" C. to about 1 per cent. at 300" C. and is apparently still diminishing at lower temperatures. In 1921 there was published a brief account of the results obtained in the National Physical Laboratory, Teddington, England.2 This laboratory, however, reported that 5 per cent. of copper is soluble in aluminum at 540" C., and that this amount decreases to about 3 per cent. at 20" C. In the same year Ohtani and Hemmi3 reported a solubility of 4.8 per cent. copper at 520" C., 2.6 per cent. at 460" C. and 1.5 per cent. at 420" C.

Jan 1, 1926

By W. O. Hotchkiss

RECOVERY and profits in the mining business do not go hand in hand. Some part of an orebody can usually be recovered at a lower cost per ton than the whole orebody or a higher proportion of it. Similarly, the total of the profits that may be made from mining an orebody is in itself not a true measure of the value of the business. The yardstick for money value should be present worth, and this is particularly so for purposes of com-parison. A simple example, well within the bounds of practicability, illustrates these points: Assume a mine to have known ore reserves of 4,000,000 tons. The ore is of uniform grade but is so situated that 1,000,000 tons could be mined more cheaply than the remainder. Present operations are on the basis of complete recovery of the ores. Output is 100,000 tons per year at a profit of $1 per ton. It is estimated that the 1,000,000 tons of readily accessible ore could be mined at the same production rate but at a profit of $2 per ton. For an output of 100,000 tons each year at a profit of $1.00 per ton, the mine will have a life of 40 years; will produce $4,000,000 of total profit, and, at Hoskold rates of 8 and 4 per cent, will have a present value of $1,104,690. If only the easy one-quarter of the ore is considered, with an output of 100,000 tons each year, at a profit of $2.00 per ton, that part of the mine will have a life of 10 years, will produce total profits of $2,000,000, and at rates of 8 and 4 per cent will have a present value of $1,224,800. . Under conditions such as these, then, one-quarter of the reserve ore promptly mined is worth some 10 per cent more than the entire reserve would be on an average basis extending over the longer period. Assume further that one-half, or 2,000,000 tons, of the reserves could be promptly mined at the same yearly rate of 100,000 tons at a profit of $1.50 per ton. Then this part of the mine would have a life of 20 years, would produce total profits of $3,000,000, and would have a present value of $1,320,630; approximately 20 per cent greater than for the whole ore-body on an average basis for the longer period.

Jan 1, 1936

By Arthur Notman

THE raw material men in all industries, and copper is no exception, are accustomed to think of them- selves as the whole show, and not without justice, for if there were no copper mines the world would have no copper. Nevertheless, many different things costing money and resulting in profits must be done to their product before it is ready for the world's use. In other words, they are making the frequent mistake of Chinking in terms of partial costs. Nobody really uses electrolytic copper. Possibly that is why nobody seems willing to pay anything for it. The manufacturers, being canny, do not buy any more electrolytic than they feel that they can work up and sell profitably, although they like to make the raw material men Chink that they will take all that can be produced. This is a state of affairs that has aroused my sympathy and curiosity, and has induced me to study the financial history of the copper wire and brass industry of the country or such portion of it as publishes any records readily available to the curious minded. About 60 per cent of the electrolytic copper used in this country is drawn into wire and consumed by the electrical industries. The remaining 40 per cent is

Jan 1, 1926

By J. E. Johnson

At the Cleveland meeting of the Institute in October, 1912, I had the honor to present a paper outlining the conditions surrounding the charcoal iron industry…

Jan 1, 1915

By Samuel S. Wyer

THE installation of the gas-producer power-plant in America has been so unusual that all engineers have viewed it with in¬terest; a large majority, however, regard it with a lack of con-fidence and many with positive distrust. Despite the fact that European engineers have usually been less inclined to take the initiative along experimental lines than are Americans, they have, nevertheless, developed the gas-producer plant to a very high state of efficiency to which they were forced by the neces¬sity of economy in fuel-consumption. The gas-producer power-plant is so common in Europe that engineers as well as the general public regard it with the same degree of confidence that is now universally placed in steam¬plants. Gas-engines, both small and large, are in general use there, and central stations, aggregating several thousand horse¬power, are quite numerous. The fact that gas-producer power-plants have received so little attention in America may be attributed to five conditions:-1', ignorance and prejudice; 2, newness of work; 3, in-

Mar 1, 1905

By J. WILLIAM WETTER

WHEN the privilege was extended to me to address this meeting I could not help but make a mental review of my own activities and experiences in connection with association work. After having spent about 16 years in the mining engineering field, I entered into the operating branch of coal mining which afforded, about 12 years ago, my first opportunity of attending a meeting of our local Association and sitting in with the "big boys" of the industry. This was quite a thrilling experience because I had heard a great deal about the various operators who belonged to the Association and knew, or at least thought I knew, that a certain group dominated its affairs and that a "clique" was in control of a sizable "roller" which could be "steamed up" at will to flatten out any opposition which might appear upon the horizon or under it, too, for that matter. Now, I was to have the privilege of observing this "clique" at first hand, of seeing a small group making the policies and shaping the destinies of a great industry and planning the activities of an important Association while a large majority of the members would sit by either complacently or otherwise with the full knowledge that the "roller" was in waiting to reduce them to ribbons at the first sign of resistance.

Jan 1, 1930

By A. V. UDELL

OF all the metals that have from time to time been called the "Wonder Metal," mercury, often called quicksilver, is probably the most deserving of this designation. A wonder metal it must have been to those workers of an earlier day who named it after that Latin god of commerce and gain, characterized as the fleet messenger of the gods and the conductor of souls to the lower world. The word mercury has been used to indicate a carrier of tidings, a bearer of news, a nimble or clever person, a hawker, and a skillful thief. All of these attributes, and more, are recognizable in this metal, the technical terminology of which is "Hydragyrum," meaning water-silver, and from which the chemical symbol "Hg" is derived. Fickle in its occurrence in nature, simple in its metallurgy, illusive in captivity, it serves man in life or death, in war or peace, in commerce, science and arts, in mining, agriculture, and forestry with a versatility found in no other element.

Jan 1, 1929

By Thomas Fraser, David R. Mitchell

THE primary purpose of the loading plant is to transfer the finished product from the preparation machines to the railroad car, truck, or barge in which it is to go to market. Secondary purposes of the loading plant are: to prevent excessive degradation of sizes during loading, to reduce segregation as much as possible, and to prevent excessive quantities of very good or off-grade coal from entering any one car. Nonuniformity of consignments is one of the chief sources of com- plaints by consumers and coal merchants. A properly designed loading plant will do much to reduce complaints and ensure uniformity, not only from shipment to shipment but also in each individual consignment along the length of the car and in cross section. DEGRADATION IN STORAGE, LOADING AND SHIPMENT The object in loading is not only to handle the coal without breakage and segregation, but also to produce a well-trimmed load that will ride to its destination without spillage or breakage en route. The small sizes present in a car of prepared coal as received by the purchaser consist-of: missed small sizes not screened out in the preparation plant, breakage during loading, and breakage caused by handling en route. For domestic sizes of anthracite shipped from the Pennsylvania anthracite field to Atlantic coast cities, the dealers' lass because of breakage in loading and shipment amounts to from 2 to 5 per cent and for anthracite shipped to Middle West cities, the loss is 8 to 9 per cent. This difference is in part because dealers in the Middle West rescreen their coal more thoroughly than is usual in the East. One dealer handling Illinois No. 6 coal shipped from southern Illinois mines to Chicago reports an average size loss of 10 per cent when lump coal is unloaded with a fork. This runs as low as 5 per cent for carefully loaded coal and as high as 15 per cent for carelessly loaded coal.

Jan 1, 1943