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By Charles Jones

IN the winter of 1902, while occupying the position of mining and examining engineer for the Mountain Copper Co., Ltd., of Keswick, Cal., I had occasion to discuss with the General Manager, among other things, the question of the enormous waste of sulphur in smelting cupriferous, pyrite ore, and to cast about for means to utilize this waste or to render the fumes innocuous to vegetation. The decreasing rate of production of California farms, the consequent need of fertilizers, and the opportunity thus offered to utilize large quantities of sulphuric acid in the manufacture of superphosphates naturally brought the subject to the practical and commercial side of phosphates. I was informed that the company had made efforts to find phosphates in the West, without success. I advised as a start placing inquiries for phosphate deposits on the Pacific coast in the current mining ,journals. This was done, with the result that in January, 1903, from an advertisement in the Mining and Scientific Press we got track of a deposit in Rich county, Utah, through T.J . Wilson, of the Southern Pacific railroad in San Francisco. As soon as snow in the mountains would permit, in May, 1903, I undertook an examination of the property, with the result of recognizing the importance of the find, in spite of its lack of facilities for transportation at a commercial figure. On June 15, 1903, I concluded my report by saying, "This may be one of the world's deposits of phosphates." On Nov. 17, 1903, I concluded my report for the season in the following words : " I have now no hesitation in saying that I believe the Carboniferous formation so largely developed in the Wasatch mountains of Utah and the mountains of the Great Basin will prove to be one of the greatest storehouses of phosphoric acid in the world."

Jan 10, 1913

By D. W. Jessup

THE handling of native labor is offering an interesting problem that requires diplomacy. It is difficult to induce many of the men to leave their villages and enter into regular work. They do not feel the necessity of manual labor other than to obtain sufficient money to pay the annual hut tax and to buy a little clothing. The ground provides mealies (corn) which means food and beer, he hunts and catches fish, so why work? But gradually, as the native becomes more civilized, his wants increase and his ideas change; he now needs money to supply his desires and eventually he must work more. So in time it is hoped that the labor market will be better supplied.

Jan 1, 1931

By T. T. Read

TWO papers on health and safety were given Thursday afternoon when a joint session of the Health and Safety Committee and the Mining Methods Committee was held. T. T. Read presided and the first paper, on ventilation at Climax, was presented by the author, L. H. Glanville. In the subsequent discussion by Cloyd M. Smith, P. B. Bucky, B. F. Tillson, D. F. Haley, J. L. G. Weysser, and others a number of interesting points not covered by the paper, which appears in full in the January Mining Technology, were brought out. Ventilation troubles in mines so often hinge on the air being too hot and damp that it was interesting to hear of one where it is frequently too cold and too dry.

Jan 1, 1943

By AIME AIME

CONVENTION plans for the A.I.M.E. Regional Meeting to be held on the Minnesota Iron Range Aug. 12 to 1.5 are being completed to give the visiting member?s from all parts of the country a wide variety of technical and recreational features. High spots of the social events are the official dinner, dance, luncheon and golf: and of course, special provision is being, made for the entertainment of visiting ladies. The technical sessions will fit in with scheduled trips to view all phases of mining, beneficiation and transportation of iron ore. Men from the West and Southwest will find much of interest in the detail of the mining operations. A trip to the steel plant of the

Jan 1, 1941

By R. S. Olson

An analysis of the wash thickener-two stage filtration circuit was undertaken to quantitatively describe the circuit performance. On the basis of information developed in this study, the factors of major importance in reducing soluble loss are: filter wash, wash zone size, filter capacity, filter feed pulp dilution, blow back, filter cloth, water to repulp, water to primary wash, water to feed pulp and thickener underflow. The wash thickener-two stage filtration circuit has been used in many hydrometallurgical plants to separate solute from leach solids. As many as 20 to 30 plant operating variables determine the performance of the wash circuit and hence the soluble loss. The complex relationships of these variables, with each other and with soluble loss, make the evaluation of their effect on mill performance difficult. An analysis of this type of circuit was undertaken to quantitatively describe the circuit performance. THE CIRCUIT The diagram in Fig. 1 represents the operation of the wash thickener-two stage filter circuit. This circuit provides for counter current, cross current or for a combination of countercurrent-cross current operation. The feed pulp stream, J, is intended to include any solution or water, other than primary and secondary filtrate, which enters the wash thickener. Except for filter washing, the operations in the circuit are simple mixing operations which can be described by material balance. The concentration of solute in the filtrate and cake solution after application of wash liquor cannot be described by simple material balance. The displacement washing equation, derived by Rhodes1 and extended by Choundhury and Dahlstrom,2 appears to best describe this case of miscible displacement in porous media. In a useful form, it is

Jan 1, 1963

By Charles R. Keyes

A COMPLETE transformation has taken place in the boras industry during the year 1908. A most remarkable factor in this radical change in method of producing the crude borates has been its removal from the realm of industrial chemistry to the field of mining. With the development of extensive deposits of borate-minerals interstratified in thick sequences of Tertiary clays and sands, their winning becomes a strictly mining-enterprise, of the same kind and of the same certainty as the digging of coal or iron-ore. The major supply of the world's production of commercial borax now comes from the United States. While formerly all of the boric salts of commerce were laboriously extracted from the waters of saline lakes of the arid regions, or from the bottom-salts of desiccated ponds, it later was largely slowly leached from ancient desert shales and clays. During these periods the borax industry was a very hazardous and expensive vocation.

Oct 1, 1909

By H. H. Dreissen, F. J. Fontein

The operating principle of the classifying cyclone has been described often but some special aspects of the cyclone receive further clarification here. In addition, several uses of the classifiers are summarized and made clear by means of practical examples. In coal and ore washeries, the washing cyclone is widely used for the separation by specific gravity of sizes up to about 12 mm. This application has lately been extended to the separation by specific gravity of particles up to about 50 mm. This use makes special demands on the construction and wear resistance of the cyclone. The sieve bend, a development of the Dutch State Mines which is less well known than the hydrocy-clone, is dealt with at some length. The sieve bend is an apparatus designed for wet screening. Attention is given to the variables influencing the performance of the sieve bend. Hydrocyclones are now so widely applied that it would be difficult to find an industry not, directly or indirectly, using them or knowing how to use them since publications on this subject abound.1-3,5,9-11,13-15 However, because of the large number of variables influencing the operation of classifying cyclones, it is not entirely possible to calculate the results of this type of cyclone. Therefore, a number of lesser known variables will be discussed here along with some special applications of the classifying cyclone. FACTORS INFLUENCING CYCLONE CLASSIFICATION Shape of Particles: The shape of particles may cause a much coarser classification than the one expected, considering the sieve analysis and the cyclone dimensions chosen. This was clearly shown by feeding a mixture of spheres and disks in water into a cyclone. The spheres were 0.36 mm diam and the disks, 3 mm diam and 0.03 mm thick. These dimensions were chosen in order that the disks and spheres might have the same rates of fall under gravity. Both spheres and disks had a specific gravity of 1.05. The results obtained with these particles in a cyclone are summarized in Table I. Test No. 2 shows that the catch of spheres was

Jan 1, 1963

By George Burrell

J. S. HALDANE, M. D., F. R. S., Oxford, England (communication to the Secretary?).-The valuable paper of Messrs. Burrell and Gauger is of special interest to me as, through the courtesy of the management, I had an opportunity of visiting the Portland mine, Cripple Creek, in 1911, in connection with the investigations on acclimatization to high altitudes, carried out on Pike's Peak, near Cripple Creek, by Professors Yandell, Henderson and Schneider, Dr. Douglas and myself.1 The analyses of one or two samples of the vitiated air were entirely confirmatory of those of the authors. A fatal accident owing to two men being lowered down a shaft filled with the gas had occurred in a neighboring mine just before our visit.

Jan 12, 1916

By K. G. Gorling, S. J. Wallden, N. B. Lindvall

It is the policy of The Metollurgical Society to provide, in the TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME, a prompt and accurate medium for publication of reports of significant new research in both the scientific and engineering aspects of metallurgy. Papers submitted to the Society are judged by competent reviewers according to established criteria for technical merit, accuracy, originality, and presentation. STAFF: Editorial Director, Rixford A. Beals; Associate Editor, James J. Burke; Assistants, L. Capria and R. K. Larkin. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: A. W. Thornton, Choirmon; Dennis Carney, John Chipman, J. C. Fulton, J. H. Hollomon, H. tl. Kellogg, A. E. Lee, R. Maddin, J. D. Sullivan, and O. Swan. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division T. B. King. Cha~rmon; S. J. Dickenson, R. P. Hermsdorf, R. Schuhmann, Jr.. and P. T. Stroup. Institute of Metals Division: Robert Maddin, Chairman. F. Lincoln Vogel, Jr., Vice-chairman, W. A. Backofen, R. W. Balluffi, J. H. Bechtold, M. B. Bever, R. S. Busk, C. G. Goetzel, Paul Gordon, C. D. Graham. Jr., Robert F. Hehe-mann, R. I. Jaffee, F. E. Jaumot, Jr., lrving R. Kramer, A. J. Leno, Horold Margolin, C. J. McHorgue, Russell A. Meussner, J. 6. Newkirk, H. W. Paxton, G. E. Pell~ssier, I. S. Servi, Alan U. Seybolt, A. J. Sholer, and Sack Wahsburn. Iron and Steel Division: J. C. Fulton, Chairman; T. B King, F. C. Langenberg, W. O. Philbrook, and T. B. Winkler. Published bimonthly by the American Institute of Mining Metallurgical and Petroleum Engineers Inc., 29 West 39th Street, New York 18, N. Y. Telephonne pennsylvania 6-9220.Petroleum Subscription Engineers$20 per year for non-AIME members in United States and North South and Central 6-9220.SubscriptionAmerica $25 toreign; $5 for AIME members. Single copies, $4.00, iinalo copies Southfpr;ign,andCentral $5 00. The AIME 'is $25not responsible for any statement made or opinion expressed in its publications Copyright 1958 1958 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . Registered coble address, AIME New York . . . Indexed in Engineering Index, Industrial Arts Index, ...and Chemical Abstracts . . . Application for second class mail privileges IS pending at New Yark, N. Y. Volume 212, Number 2.

Jan 1, 1959

By W. E. Curran

For years the geographical isolation of the Southern iron-ore district from the great producing centers in the North and East enabled it to meet its conditions and solve its own problems without regard to the practices and policies of other districts, but during the past few years distances have been shortened, practices and wages are being standardized, and these changing conditions have brought new problems to the South. Development of Pig Iron in the South The development of the pig-iron business in the South was very slow during its early years, gained speed rapidly in the latter part of the nineteenth century, reached its peak in 1918 and was on the decline before the depression that began in the latter part of 1929. The first blast furnace in Alabama was built at Cedar Creek in 1818, the year before the state was admitted to the union. In 1830, Daniel Hillman was sent from Tuscaloosa to found an iron works in Roupes Valley, where rich pockets of brown ore were numerous. He built a forge on the site of what later became Tannehill furnace and called it the Roupes Valley Iron Works. There pots, pans, plows, and horseshoes were made of metal from his Catalon forge; shaped by a large hammer operated by water power. Daniel Hillman died in 1832 and the ironworks lay idle until 1836, when Col. Ninion Tannehill bought the property, rebuilt the forge and, using slave labor from his plantation, operated and enlarged the works. By 1845 he had built two crude furnaces and did a flourishing business in ovens, skillets and kettles, which found a good market all over the South. In 1855, the plant was sold by Colonel Tannehill to Moses Stroup, an experienced ironmaster from Pennsylvania. He tore down the old furnaces and built a new plant, the ruins of which stand today (Fig. l). This furnace plant operated continuously until it was destroyed by Northern troops in 1865. It was never rebuilt, so that the shell in the picture is the same furnace that made many tons of guns and shells for the Confederacy during the war period.

Jan 1, 1938

By W. E. Curran

For years the geographical isolation of the Southern iron-ore district from the great producing centers in the North and East enabled it to meet its conditions and solve its own problems without regard to the practices and policies of other districts, but during the past few years distances have been shortened, practices and wages are being standardized, and these changing conditions have brought new problems to the South. Development of Pig Iron in the South The development of the pig-iron business in the South was very slow during its early years, gained speed rapidly in the latter part of the nineteenth century, reached its peak in 1918 and was on the decline before the depression that began in the latter part of 1929. The first blast furnace in Alabama was built at Cedar Creek in 1818, the year before the state was admitted to the union. In 1830, Daniel Hillman was sent from Tuscaloosa to found an iron works in Roupes Valley, where rich pockets of brown ore were numerous. He built a forge on the site of what later became Tannehill furnace and called it the Roupes Valley Iron Works. There pots, pans, plows, and horseshoes were made of metal from his Catalon forge; shaped by a large hammer operated by water power. Daniel Hillman died in 1832 and the ironworks lay idle until 1836, when Col. Ninion Tannehill bought the property, rebuilt the forge and, using slave labor from his plantation, operated and enlarged the works. By 1845 he had built two crude furnaces and did a flourishing business in ovens, skillets and kettles, which found a good market all over the South. In 1855, the plant was sold by Colonel Tannehill to Moses Stroup, an experienced ironmaster from Pennsylvania. He tore down the old furnaces and built a new plant, the ruins of which stand today (Fig. l). This furnace plant operated continuously until it was destroyed by Northern troops in 1865. It was never rebuilt, so that the shell in the picture is the same furnace that made many tons of guns and shells for the Confederacy during the war period.

Jan 1, 1938

Dimitri Konstantinovitch Tschernoff, was horn in Petrograd, Russia, on Nov. 1, 1839, and died in Yalta (Crimea) in the south of Russia, on Jan. 2, 1921. He obtained his early education in the Russian Gymnasium, corresponding to the American high school, and in the Technologic Institute. On graduation from this Institute in 1858, he was engaged as a professor of geometry and algebra and later became a librarian and superintendent of the museum in the same Institute. He also attended lectures in the mathematical physics section at the Univrrsity of Petrograd from 1859 to 1862. In 1866, Professor Tschernoff left the Technologic Institute and entered the employ of the Obouchoff steel plant, founded in 1863 for the manufacture of guns. Here he did his most important work on the heat treatment of steel, its crystallization and metallography. In 1880, he left the Obouchoff plant and went to the south of European Russia, where he discovered and developed some rock-salt mines. This enterprise brought him a rather large fortune. In 1884, he returned to Petrograd and during the next four years held several prominent positions in government departments. In 1899, he became professor of metallurgy in the Michael Artillery Academy, and retained that position until the time of the Russian Revolution. In 1902, Professor Tschernoff was elected an honorary member of the American Institute of Mining and Metallurgical Engineers. In September, 1917, Professor Tschernoff was sponding his vacation, as usual, in the city of Yalta (Crimea) in the south of Russia, with his wife and one of his daughters. The revolution progressed so rapidly that they were unable to return to Petrograd, and were compelled to stay in Yalta without provision for the winter season. Suffering from hunger. and lack of sufficient clothing, and deprived of his books, Tschernoff nevertheless continued his studies and gave a number of lectures on steel at the Polytechnic Institute. At the same time he worked hard on some. mathematical problems. His health broke down through long-continued under-nourishment. His works in the metallurgical field are well known to the students of metallurgy; good abstracts of his most important papers were published in Revue de Metallurgie (1915, pp. 829-882) in commemoration of his 75th birthday.

Jan 1, 1922

Dimitri Konstantinovitch Tschernoff, was horn in Petrograd, Russia, on Nov. 1, 1839, and died in Yalta (Crimea) in the south of Russia, on Jan. 2, 1921. He obtained his early education in the Russian Gymnasium, corresponding to the American high school, and in the Technologic Institute. On graduation from this Institute in 1858, he was engaged as a professor of geometry and algebra and later became a librarian and superintendent of the museum in the same Institute. He also attended lectures in the mathematical physics section at the Univrrsity of Petrograd from 1859 to 1862. In 1866, Professor Tschernoff left the Technologic Institute and entered the employ of the Obouchoff steel plant, founded in 1863 for the manufacture of guns. Here he did his most important work on the heat treatment of steel, its crystallization and metallography. In 1880, he left the Obouchoff plant and went to the south of European Russia, where he discovered and developed some rock-salt mines. This enterprise brought him a rather large fortune. In 1884, he returned to Petrograd and during the next four years held several prominent positions in government departments. In 1899, he became professor of metallurgy in the Michael Artillery Academy, and retained that position until the time of the Russian Revolution. In 1902, Professor Tschernoff was elected an honorary member of the American Institute of Mining and Metallurgical Engineers. In September, 1917, Professor Tschernoff was sponding his vacation, as usual, in the city of Yalta (Crimea) in the south of Russia, with his wife and one of his daughters. The revolution progressed so rapidly that they were unable to return to Petrograd, and were compelled to stay in Yalta without provision for the winter season. Suffering from hunger. and lack of sufficient clothing, and deprived of his books, Tschernoff nevertheless continued his studies and gave a number of lectures on steel at the Polytechnic Institute. At the same time he worked hard on some. mathematical problems. His health broke down through long-continued under-nourishment. His works in the metallurgical field are well known to the students of metallurgy; good abstracts of his most important papers were published in Revue de Metallurgie (1915, pp. 829-882) in commemoration of his 75th birthday.

Jan 1, 1922

By E. W. Krampert

Oil development continued active in Wyoming during 1937, with much of the interest centered on prospecting for new pools, following a rather intensive seismograph play in 1936. The new fields of Lance Creek, Medicine Bow and Quealy were the centers of intense development in proved areas, but routine drilling occurred in most old fields. A new and deeper producing horizon (the Leo sand) was opened up in the Lance Creek field, which materially extends the producing area and will probably account for continued active development during 1938. The discovery in 1936 of oil in the Eocene Wasatch formation at Powder Wash, northwestern Colorado, tended for a time to stimulate prospecting in the deep Tertiary basins, but this interest as rapidly declined after drilling several failures on similar structures and the discovery that the productive area at Powder Wash itself was very small. A most interesting test of an Eocene structure was drilled by The Superior Oil Company of California on the South Baggs structure, in Carbon County, Wyoming. South Baggs is one of the best developed structures in the Red Desert Washakie Basin, which also includes the Hiawatha gas field and the Powder Wash gas and oil field. The Superior Oil Co. started the well according to contract but apparently had lost interest in the prospects, for it abandoned the well at 2138 ft. without testing the oil-bearing and gas-bearing horizons of the Wasatch. The Sinclair Wyoming Oil Co. drilled a deep test in the Muskrat gas field to the Madison. This well discovered oil in the Embar formation, which was considered noncommercial because of depth. After the Embar was abandoned the hole was plugged back and the various sands tested by shooting through the casing with the Lane-Wells gun. The Lakota sand was found to contain high-pressure gas and the well was completed as a 24-million-foot gasser at 2175 lb. rock pressure. This is a new sand in an old field. The Italo Petroleum Co. drilled a flank well on the Hamilton dome structure and found oil in the lower Embar formation. Thk merely extends the limits of production, as one old well on the structure had

Jan 1, 1938

The oil production in Bahrein for the year 1937 was 7,762,264 bbl., a monthly average of 646,855 barrels. Sufficient potential production had been developed in the Second Pay (Main Pay) at Bahrein by the end of 1936 to supply the anticipated crude demand, and the drilling program was changed from straight development to partial exploration during 1937. Two nonproductive wells were drilled to test the Third Pay at a depth of about 2900 ft., or some 900 ft. below the top of Second Pay. As a result of this exploratory work, the normal drilling program was slowed down and only eight new wells were completed in the Second Pay during 1937, making a total of 45 producers from the Second Pay. The deep test was drilling at 5081 ft. at the end of the year. A 550-ft. section (termed Fourth Pay) of porous limestone interbedded with anhydrite was topped at about 4150 ft. Numerous drill-stem tests indicated that the limestone was very permeable and that it carried large volumes of natural gas under high pressure together with a small amount of high-gravity oil or condensate. Drill-stem tests also indicated that the bottom 50 ft. of the 550-ft. section carried an encouraging amount of heavier oil, gravity about 37" A.P.I., with characteristics similar to the oil produced from the Second Pay. A well was started somewhat down-structure from the deep test to better determine the oil-producing possibilities of the Fourth Pay. Some refinements in drilling technique were adopted during the year. All wells started to the Second Pay were drilled with rotary from the surface. The top 1500 ft. of porous limestone section, formerly drilled with cable tools, is now drilled with rotary without circulation, using water to wash the cuttings into cavities. The shale section from this point to the top of the oil horizons is drilled with natural mud circulation. The productive horizons are drilled with oil circulation under pressure control. A second satisfactory method of completing wells was developed when the two Third Pay test wells were plugged back and gun-perforated through cemented casing opposite the Second Pay, with good results.

Jan 1, 1938

By GEO M. FOWLER

AN appraisal of the activities of the mining geologists during 1936 clearly indicates the ever in- creasing utilization of geology in the search for ore. Few men with geo- logic training are idle at present; this is particularly true regarding recent graduates. Many have accepted employment in distant fields, such as the Philippines and South America, and greatly increased mineral production from these places reflects their activities. In North America, regions of intense mineralization formerly important are being restudied in greater de- tail and with better understanding; as a result, new mineral wealth is being found in many such districts. Much is being done by private companies and individuals, and it is to be hoped that mining companies will increasingly make available the purely scientific results of such studies by permitting their geologists to publish. On such generosity to a large extent will future advances in ore finding depend.

Jan 1, 1937

By Sydney H. Ball

AMERICAN consumption of industrial diamonds has increased five fold in the past 25 years and today accounts for 15 to 20 percent of the world's sale of rough diamonds. In another decade the value of industrial diamonds sold may well equal or exceed that of gemstones. It is generally understood that industrial diamonds are one of the strategic minerals being stocked by the Government in the present crisis to ensure rapid and efficient armament production. Diamond die making is a trade largely confined to artisans in Switzerland and in certain parts of France. Today, in addition to turning out pilots, we should train expert artisans in diamond die making, for thousands of miles of tremendously small-gauge wire will be needed to make the instruments by which the efficiency and safety of these pilots is assisted.

Jan 1, 1941

By S. A. Falconer

The benefication of non-sulfide or non-metallic minerals by froth flotation has been practiced commercially for at least 30 years. In the pioneer stages of development of this flotation art, most of the promoters investigated were fatty acids or soaps that had been found to float sulfide minerals. When commercial application of froth flotation started to assume importance in the late 1920' s and 1930's, a great deal of fundamental research work was done in the laboratory (11-14, 19, 22, 23, 26, 29, 32). Among other subjects, this work included studies of the relative effectiveness of the different fatty acids and their salts on the flotability of various non-sulfide and non-metallic minerals. The successful present-day use of fatty acid and petroleum sulfonate type promoters results from better understanding of the principles of non-sulfide flotation plus the developnent of effective selectivity modifying agents. Many investigators have contributed to a greater appreciation of the numerous interrelated factors involved in fatty acid and soap flotation of non-sulfide minerals. Of these, mention should be made of recent fundamental studies by Tagart and Arbiter (31); Wolstenholme and Schulman (35); Schulman and Smith (28); Wark and his co-workers(3,4) Du FIietz(l5); and J. Leja(24). According to J. Rogers, K. L. Sutherland and E. E. and I. W. Wark(27), "the basic requirements for a 'collector' in flotation are that it shall form a film over the surface of the mineral to be floated and that this film should be oriented so that hydrocarbon (non-polar) groups form the effective surface." When modified in that way, the mineral surface possesses some degree of air avidity. All investigators would agree with Taggart, Taylor and Ince (33)that such a film can be produced only if the collector compound contains an active (polar) group to be attracted to the mineral surface, as well as the non-polar group. The commonly used anionic-type promoters for non-sulfide, non-metallic and metallic oxide ores include: 1. Fatty acids, and their soaps and emulsions. 2. Fatty acids residues — "pitches" and "foots." 3. Sulfonated and sulfated fatty acids and so-called "petroleum sulfonates." 4. Paraffin chain salts — sulfonated and sulfated higher alcohols. 5. Cyclic organic acids or salts, such as naph-thenic acid and naphthenates. Certain fatty acids are more effective than others as promoters for particular minerals under certain specified conditions. Some of the more costly fatty acids or collectors of the paraffin chain salt type may give improved selectivity in some instances and are being used commercially in a limited number of operations. Local availability may dictate the choice of the fatty acid used — for example, the use of palmoil fatty acid for flotation of copper carbonate ores in the Belgian Congo. Coconut oil fatty acids have also found limited use.

Jan 1, 1961

By Elmer R. Kaiser

G. A. Vissac (Consulting Engineer, Vancouver, B. C.) —Some of the data presented in this paper, in connection with cost studies of washed coals, should be clarified and qualified. Washing a raw coal down to a low ash content may mean higher losses in refuse, but the cost of the operation may be more than compensated by the increased value of the resultant product. However, careful engineering and accurate machinery are required to insure maximum profits. Washing at a low gravity separation demands a very accurate automatic process, chiefly when the small sizes of coal are being handled. Coal consumers today are buying mostly on a Btu basis, cognizant of the fact that low ash contents result in lower installation costs and in savings in handling and transportation charges. The attached Table X gives the actual balance sheets of the various cleaning operations corresponding to various ash contents for the two coals presented in the paper, using the old technique of a two-products separation. or the new technique, now commonly used in Europe, of a three-way separation made possible by new methods and new equipment. Savings in capital costs, handling, and transportation have been calculated on the basis of a delivered cost f.O.b. plant of $10.00 per ton of coal at 16.5 pct ash (actual 1953 average price reported by Consolidated Edison, N. Y.), and of $3.50 at the mine also for 16.5 pct ash coal. In both cases this corresponds to values of 126 and 4.26 per 1 pct of combustible and per ton, respectively, on delivered and on at the mine prices. As an example, the middle western coal at 16.5 pct ash, raw, washed down to 4 pct ash in a two-way process will give 53.75 pct of clean coal at 4 pct ash and 46.25 pct of refuse at 31 pct ash. The value of the losses will be 0.4625x(100—31)x0.042 = $1.34. Add the cost of washing, capital, and operation, which is $0.35. The total cost will then be $1.69. But with a three-ways separation we will have 53.75 pct of first-grade coal at 4 pct ash, 37.25 pct second-

Jan 1, 1955

By Harry J. Evans

DURING the fury of the conflict it was believed quite generally that World War II was being fought for and would accomplish a permanent peace. Yet, before the guns were actually stilled on all fronts, the American people realized that the devastated world would continue to be dominated by suspicion and uncertainty. The misunderstandings which rapidly developed indicated that it may prove unwise to rely wholly on mutual international agreements and contracts to avoid war. Before the celebrations of V-Day died down serious thought was being given toward measures for preparedness for the next conflict. Along with a realization of the enormous loss of life caused by the destructive forces of war, the American people came to understand the seriousness of the rapid and unwarranted depletion of our natural resources. During the last half of 1945 the question of stock-piling strategic and critical raw materials for a future national emergency became an intensely live subject.

Jan 1, 1946