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By W. L. Remick

The hydrotator coal-cleaning process was developed as an economic necessity to meet the ever-increasing demand for an inexpensive method of cleaning coal down to the sizes ordinarily referred to as "dust." As the most urgent demand seemed to be in the anthracite field, all experimental work has been conducted in that territory during the past two years, with the exception of a few months during the strike of 1925-26, when some experiments were performed in the Alabama bituminous fields. The first commercial plant was constructed at the Middle Creek Colliery of the Philadelphia & Reading Coal & Iron Co.,. Pottsville, Pa. This plant is now operating. Application The field of application of the process is: 1. Cleaning anthracite fines, ordinarily described as "slush" or "silt." Slush contains all sizes from 3/32 in. down to and including I(dust." (Anthracite passing a 3/32-in. mesh is also referred to as No. 2 Barley and No. 4 Buckwheat.) 2. Cleaning sizes too fine for recovery by other methods. 3. Removal of coal from sand circulated in the Chance sand-flotation process. 4. Cleaning of bituminous sizes from % in. down to "dust." 5. As equipment for the performance of the froth flotation process. 6. Other separating, extraction and washing processes which may be considered outside the realm of coal cleaning. Principle of Operation Fig. 1 shows the method of classification practiced under the Hydrotator patent.' In coal cleaning the machines are operated as "hindered settling" classifiers, the flow of solids and liquids being so controlled that the units may be combined in series.

Jan 1, 1927

By Subhas G. Malghan

Feldspathic deposits occur widely throughout the United States, but North Carolina, California, Connecticut, and South Carolina accounted for over 80% of the total domestic feldspar output for the year 1973.1 Pegmatites and granites constitute the major feldspar reserves of the United States, 2 and in addition, feldspar is produced as a byproduct by firms whose major products are spodumene and mica. 3 Feldspar flotation is practiced in the United States, Mexico, Finland, Norway, West Germany, Japan, and the USSR. According to the US Bureau of Mines estimates, the production of feldspar in the United States and rest of the world were 704,000 and 2,514,000 t, respectively. Feldspar is principally used as a flux in making glass, pottery, porcelain, enamel, tile, and other ceramic products. In recent years, the domestic feldspar industry is faced with a number of problems. As a result of increased cost of energy and the introduction in 1972 of new legislative programs relating to air, water, and noise pollution, land-use restrictions, and mined-land rehabilitation, the production costs have increased. Apart from the increased cost of operation, an operational problem exists with the feldspar producers in North Carolina, especially those in the Spruce Pine area. This problem is concerned with the use of hydrofluoric acid in the feldspar flotation. Feldspar producers in Spruce Pine, NC, have been discharging process waste water into the North Toe River. The mill waste water contains active fluoride ions. Fluoride in excessive concentrations is undesirable in waters used for drinking. It is stated that water containing 0.9-1.0 ppm fluoride will seldom cause mottled enamel on children's teeth; and for adults, concentrations less than 3-4 are not likely to cause endemic cumulative fluorosis and skeletal effect. Although the literature on this subject is rather confusing and inconclusive, the inference that concentrations over 4 ppm may affect bone structure is clear. According to the recent Federal Register,4 maximum fluoride level of 1.4 ppm at 79°-98°F is considered to be adequate and safe for the protection of health of the consumers. The EPA and state environmental agencies have accelerated their drive to reduce water pollution on a faster schedule. By 1977, the EPA specifications for maximum contaminant level of fluoride ions in the discharge waters of feldspar milling operatins is expected to be reduced to 2.0 ppm. The other problems of using hydrofluoric acid are the following: toxicity, hazards of handling and storage, and high cost as compared to other inorganic acids (almost 16 times the cost of sulfuric acid). In order to reduce fluoride levels in mill discharge waters, mining companies have taken the following steps: I) Recirculating a part of their mill water. Even though recirculation of mill water seems to be a novel method of reducing fluoride contamination of the discharge water, there are certain operational and handling problems. 2) Conducting research on the treatment of fluorides in mill waste water. The technology of treatment of fluoride ions has received considerable interest in the recent years. A recent research report5 estimates that the cost of fluoride ion removal to meet the present specifications in the feldspar industry is approximately $0.25/t of ore processed, and about $0.50/t of feldspar produced. At the request of the feldspar producing industries in North Carolina, the North Carolina State University (NCSU) Minerals Research Laboratory has taken up a research program directed towards overcoming the fluoride ion pollution problem. After a close study of the operational, technical, and economic aspects of feldspar flotation, it was decided to attempt to replace the conventional hydrofluoric acid process. Conventional Feldspar Flotatin Using Hydrofluoric Acid Since the inception of the feldspar flotation process using hydrofluoric acid by O'Meara2,6 the process has achieved a great commercial success. In the conventional flotation separation of feldspar-quartz, hydrofluoric acid is used to suppress quartz and activate feldspar, and a long chain amine salt (acetate or chloride) is used as a collector. The bulk of amine collectors used in current feldspar operations are applied as the water-soluble acetates of the free-base amines. These products are pastes or waxy solids which are available in a range of acetic acid neutralization levels generally 50 to 100% neutralized. In spite of the problems mentioned in connection with the use of hydrofluoric acid, this process is extremely stable with respect to changes in the process variables. With the exception of a few operations, alaskite and pegmatite are the major sources of feldspar.7 In the flotation treatment of a pegmatite that contains iron-bearing minerals (heavy minerals), mica, feldspar, and silica, a logical order of removal presents itself considering the following:8 1) Mica is readily floated by an amine collector in a pulp pH 3.5. Some iron-bearing minerals will usually respond to amine collector in acid circuit with the mica concentrate. 2) Since iron minerals tend to occur invariably in the feldspar concentrate, it is desirable to remove most of these prior to feldspar flotation. A fatty acid or a petroleum sulfonate collector used in this flotation step in acid circuit will float iron-bearing minerals. 3) Using hydrofluoric acid to maintain pH of 2.5, an amine collector employed in a final step will float feldspar away from silica, usually leaving the latter in the tailing as a high-grade silica concentrate. The problems connected with the flotation separation of feldspar-quartz arise due to the similarities in their chemical structure. Therefore, any reagent system that is likely to succeed in feldspar-quartz separation should have adsorption affinity towards one of the minerals and depression effect towards the other mineral.

Jan 1, 1979

By Frances Hurd

WHEN 60:40 brass is heated to 825° C., given a drastic quench to obtain the beta solid solution, and reheated, various changes take place in the structure. Reheating at 200' C. causes a fine, granular, sorbitic structure to appear which has been considered alpha solid solution. These particles coalesce at higher temperatures of reheating, and at 470° C., the alpha forms twins. A further study of these transformations was considered worth investigating.

Jan 1, 1927

By John V. Beall

Let's start at the beginning, Mr. Turner. Where and when were you born? In Lansing, Mich., on July 31, 1880. And what was your education? I went to the University of Michigan, where I got an A.B. degree in 1902; then to the Michigan College of Mines at Houghton, graduating from there in 1904 with a B.S. and an E.M. What was your first job in the mining industry, Mr. Turner, and what were you paid? In the summer of 1902, 1 was a field assistant for the U. S. Geological Survey in southwestern Idaho and southeastern Oregon, working under Israel C. Russell, professor of geology at the University of Michigan, who incidentally, had just returned from an expedition to study the effects of the eruption of Mt. Pelee, on Martinique. I was paid $60 a month and found; in addition to doing geologic and hydrographic work, I cooked many of the meals for a party of four, and wrangled four horses. I slept for four months under the stars, without a tent.

Jan 1, 1949

By W. H. Hough, P. B. Leavenworth

Development in the Upper Texas Gulf Coast during 1943 resulted in the discovery of 11 new fields as compared with 12 discovered in the same area during I942. Of the 11 new fields, eight are classed as oil and/or condensate and three as gas fields. In addition to the new discoveries, several more or less important new horizons and extensions were encountered in some of the older fields, as noted in the text under the heading "New Pays and Extensions.'' Drilling During the year, 418 wells were drilled, as compared with 356 drilled during 1942. Of these, 323 were field wells, of which 188 produced oil, 21 were gas wells and 114 were dry holes. The remaining 95 viere wildcats, 12 of which produced oil, 4 produced gas and 79 dry holes. Distribution of themwildcats with respect to the various trends may be summarized as follows: over the 91,340,492 bbl. produced in the same area during 1942. The production statistics in the text and the accompanying tables include condensate or distillate as oil production, because many Gulf Coast fields produce oils with a wide variation of specific gravities, all of which are commingled in pipe lines. Table 3 shows by counties all of the drilling and production" data applicable to this particular area. Outstanding Fields of 1943 The Upper Texas Gulf Coast covered in this report has 178 more or less active oil and gas fields, including the 1943 discoveries. Of these Table 4 lists those that were most important from the standpoint of production. Each of these fields pro duced in excess of one million barrels of oil during 1943. Some of the interesting facts to be noted from this list of some 26 oil fields are: (I) four of the fields— namely, Conroe, Hastings, Friendswood and Thompson—each produced more than 10 million barrels during 1943, whcrcas Conroe and Hastings were the only fields that produced 10 million barrels during 1942; (2) some of the older fields (discovered prior to 1920), such as Barbers Hill, West Columbia, and Hull, are still producing in excess of one million barrels annually; (3) some of the fields more than doubled their 1942 production—e.g., Anahuac and Friendswood. The large increase in production in practically all instances is the result of increased allowables from wells drilled prior to 1943 and

Jan 1, 1944

By W. H. Hough, P. B. Leavenworth

Development in the Upper Texas Gulf Coast during 1943 resulted in the discovery of 11 new fields as compared with 12 discovered in the same area during I942. Of the 11 new fields, eight are classed as oil and/or condensate and three as gas fields. In addition to the new discoveries, several more or less important new horizons and extensions were encountered in some of the older fields, as noted in the text under the heading "New Pays and Extensions.'' Drilling During the year, 418 wells were drilled, as compared with 356 drilled during 1942. Of these, 323 were field wells, of which 188 produced oil, 21 were gas wells and 114 were dry holes. The remaining 95 viere wildcats, 12 of which produced oil, 4 produced gas and 79 dry holes. Distribution of themwildcats with respect to the various trends may be summarized as follows: over the 91,340,492 bbl. produced in the same area during 1942. The production statistics in the text and the accompanying tables include condensate or distillate as oil production, because many Gulf Coast fields produce oils with a wide variation of specific gravities, all of which are commingled in pipe lines. Table 3 shows by counties all of the drilling and production" data applicable to this particular area. Outstanding Fields of 1943 The Upper Texas Gulf Coast covered in this report has 178 more or less active oil and gas fields, including the 1943 discoveries. Of these Table 4 lists those that were most important from the standpoint of production. Each of these fields pro duced in excess of one million barrels of oil during 1943. Some of the interesting facts to be noted from this list of some 26 oil fields are: (I) four of the fields— namely, Conroe, Hastings, Friendswood and Thompson—each produced more than 10 million barrels during 1943, whcrcas Conroe and Hastings were the only fields that produced 10 million barrels during 1942; (2) some of the older fields (discovered prior to 1920), such as Barbers Hill, West Columbia, and Hull, are still producing in excess of one million barrels annually; (3) some of the fields more than doubled their 1942 production—e.g., Anahuac and Friendswood. The large increase in production in practically all instances is the result of increased allowables from wells drilled prior to 1943 and

Jan 1, 1944

By C. Y. Clayton

In connection with certain cooperative work carried on between the Ordnance Department of the U. S. Army, the U. S. Bureau of Mines, and the U. S. Geological Survey during the year 1918, it was the writers' privilege to make metallographic examinations of a great many test bars and other pieces of nickel-steel gun forgings. The material studied came from many different steel plants throughout the country and consisted both of forgings that had been accepted by the Ordnance Department and those that had failed to pass the specified physical tests. In general, these tests require a minimum tensile strength of 95,000 lb. (42,091 kg.)! an elastic limit of 65,000 lb. (29,483 kg.), an 18 per cent, elongation, and a 30 per cent. reduction in area. An average chemical composition of the steel studied is 0.38 per cent. carbon and 2.9 per cent. nickel. The steel was of both basic electric and basic open-hearth manufacture. The object of the metallographic work was twofold: to assist in detecting defects in the steel and, if possible, to suggest remedies for the same; and to obtain as much information as possible in regard to the relation of the microstructure of the metal to its physical properties. The grcatcr part of the investigation was devoted to defective metal that failed to pass the ordnance specifications. Many types and kinds of more or less serious defects thus came under observation, but most of these were due to the attempts by the manufacturer to meet the enormous demand for ordnance steel with more or less inadequate equipment, and were soon remedied. Two defects, the so-called "flakes" or "snowflakes" and a certain "fibrous" or "woody" fracture, were encountered so frequently and were so disastrous to the steel that the greater part of the study was devoted to them. As a result much information as to their nature and their effects upon the steel and something in regard to some of the conditions that favor their development has been obtained. The purpose of the present

Jan 1, 1920

By E. P. Pfleider, W. G. Pariseau

This paper reports the theoretical and experimental results of an analysis of ore pass drawdown as a problem in soil plasticity. The method of analysis developed appears to be a promising technique of investigating the mechanics of fragmented materials. A reconstructed plasticity theory brings experiment and theory into reasonable agreement, and hence may provide the foundation needed for rational ore pass design. The gravity-induced movement of broken rock through ore passes is an economical method of transporting fragmented materials through large vertical distances in underground mines, provided the ore pass is well designed. Unfortunately, the design procedures now followed do not very often result in ore passes that function properly. On the one hand, the huge accumulation of empirical data pertaining to the movement of materials in gravel bunkers, storage bins, deep grain silos and other structures that have features in common with ore passes remains uncorrelated. On the other hand, there is a dearth of experimental data substantiating theoretical models of material behavior. Consequently, reliable generalizations encompassing the broad spectrum of problems involved have not been forthcoming. AS an initial step towards improving the situation, a detailed case study of two-dimensional ore pass drawdown was made. The mechanics of the process were analyzed theoretically as a problem in soil plasticity and tested experimentally through observations of a laboratory ore pass model. THEORY Taylor1 defines a soil as a "mass commonly considered to consist of a network or skeleton of solid particles, enclosing voids of varying size." Broken rock in an ore pass is such a material. In plasticity theory this material is replaced by an idealized substance that deforms elastically up to some state of stress at which slip or yield occurs,2 For com-pressive states of stress, the Mohr-Coulomb criterion is a satisfactory yield condition. After the yield point is reached, the ideal soil deforms in accordance with the concept of plastic potential.4 Under plane strain conditions the governing equations separate into a system of stress equations and a system of velocity equations.' Only stress variables appear in the stress system. The velocity system, however, contains a stress variable. The two systems are, therefore, coupled. Both systems are hyperbolic, and each has two real, distinct families of characteristic curves that coincide according to the classical theory of ideal soil plasticity. The

Jan 1, 1969

By OTTO HERRES

TITANIUM is estimated to be the ninth most plentiful element, ranking after iron, aluminum, and magnesium, and ahead of copper, lead, and zinc. Vast quantities of titanium are widespread throughout the world in ore deposits and beach sands. Before the war, processing plants were operated in England, France, Italy, Czechoslovakia, Norway, Russia, Australia, United States, and Japan. In spite of its widespread occurrence, however, the U. S. Department of Justice has held the titanium industry to be a world monopoly and action was taken in the Federal court during the summer of 1945 to enjoin international patent and marketing agreements and to restore free competition. Possibly the rather surprising lack of public familiarity with this industry of international importance arises from its astonishingly rapid development and growth in the strong hands of some of the greatest chemical companies in the world, including the important foreign companies, Imperial Chemical Industries (British), Montecatini (Italian), I. G. Farben (German), and Titan Kogko Kabushiki Kaisha (Japanese). The rapid growth of the titanium industry in the United States is indicated by a tenfold increase of ore imports in the 1930 to 1940 decade before the war began to affect shipments from overseas. The fact that the industry formerly derived practically all ore for chemical processing in American plants from foreign sources probably also accounts for lack of general public knowledge of titanium. In 1939, to meet the requirements of increasing demand for the white pigment. titanium dioxide, more than 250,000 tons of titanium concentrates moved to this country, principally from the Travancore coast of India where the ilmenite concentrate from the beach sand runs as high as 60 per cent in titanium dioxide. Global warfare put a stop to shipping and thus gave rise to the development of titanium mining on a substantial scale in the United States during 1941.

Jan 1, 1946

By L. C. Graton

[CONTENTS PAGE INTRODUCTION AND ACKNOWLEDGMENTS. By George M. Fowler2 Question 1-Is Structural Deformation of Some Character Always Necessary for the Migration of Mineralizing Solutions, Especially in Limestone or Other Dense Rock? DISCUSSION by: A. M. Bateman 10 S. F. Kelly 15 C. H. Behre, Jr 8, 13 G. B. Langford 13 T. M. Broderick11 H. E. McKinstry6 R. H. Clarke 13 D. H. McLaughlin8 J. D. Forrester for M. H. Gidel . . . 4 W. H. Newhouse13 G. M. Fowler 2, 6, 11 R. H. Sales 6 L. C. Graton 11 Edward Sampson 12 R. D. Hoffman 10 J. S. Stevenson 7 I. B. Joralemon11 L. B. Wright 2 Question 2-What Are Some of the Chemical and Physical Characteristics in Certain Beds within a Limestone Formation that Determine Their Favorable or Unfavorable Aspects as Reservoirs for Ore and Other Introduced Minerals? DISCUSSION by: G. W. Bain 17G. M. Fowler 21 C. H. Behre, Jr21L. C. Graton18 J. S. Brown 16G. F. Loughlin18 E. L. Bruce 19R. H. Sales 19 R. H. Clarke 20A. K. Snelgrove 20 Question 3-Are There Any Criteria by Which One Can Determine When Mining Operations Have Reached the Roots of an Ore Deposit? DISCUSSION by: J. M. Boutwell29G. B. Langford 29 T. M. Broderick28G. F. Loughlin25 E. Y. Dougherty27R. H. Sales 24 G. M. Fowler 22F. A. Thomson 26 I. B. Joralemon 22Edward Wisser 30 General S. F. Kelly35 References36

Jan 1, 1940

CORPORAL SHEPPARD B. GORDY Sheppard B. Gordy, a brief biography of whom was printed inn the January Bulletin, entered the employ of the Braden Copper Co. immediately on his graduation from the Sheffield Scientific School in 1912. He remained with this company four years, working up through the various grades to assistant foreman and foreman to one of the individual mines. The last year he was in its employ, he acted as general mine foreman. He was for a short time with the Chile Exploration Co. and then went with the Andes Exploration Co. (Anaconda) and remained with CORPORAL SHEPPARD B. GORDY. the latter, doing mine exploration and development work, until he sailed for home in June, 1918, to give a more personal and active service to his country in her need. He declined a tender of induction into an officers' training camp, at the urgent request of Professor McClelland supplemented by Mr. Potter, because they demonstrated to his satisfaction that he could give more valuable service to his country in helping out with the aircraft production. Being within the draft age, in order to carry out this plan, it was necessary for him to be called by his Local Board and sent to camp. This call came Aug. 26. Two weeks before that time lie had gone to Dayton, Ohio; to begin the study of aircraft production, and was sent by the Dayton Board to Camp Sherman, Chillicothe, Ohio, where he died of pneumonia on Oct. 9.

Jan 3, 1919

By W. L. Remick

THE hydrotator coal-cleaning process was developed as an economic necessity to meet the ever-increasing demand for an inexpensive method of cleaning coal down to the sizes ordinarily referred to as "dust." As the most urgent demand seemed to be in the anthracite field, all experimental work has been conducted in that territory during the past 2 years, with the exception of a few months during the strike of 1925-26, when some experiments were performed in the Alabama bituminous fields. The first commercial plant was constructed at the Middle Creek Colliery of the Philadelphia & Reading Coal & Iron Co., Pottsville, Pa. This plant is now operating. APPLICATION The field of application of the process is: 1. Cleaning anthracite fines, ordinarily described as "slush" or "silt." Slush contains all sizes from %2 in. down to and including "dust." (Anthracite passing a 32-in. mesh is also referred to as No. 2 Barley and No. 4 Buckwheat.) 2. Cleaning sizes too fine for recovery by other methods. 3. Removal of coal from sand circulated in the Chance sand-flotation process. 4. Cleaning of bituminous sizes. from 3/8 in. down to "dust. 5. As equipment for the performance of the froth flotation process. 6. Other separating, extraction and _washing. processes which may be considered outside the realm of coal cleaning. PRINCIPLE OF OPERATION Fig. 1 shows the method of classification practised under the Hydrotator patent:1 In coal cleaning the machines are operated as "hindered settling" classifiers, the flow of solids and liquids being so controlled that the units may be combined in series.

Jan 1, 1927

By Charles W. Bloomquist

The profitability of miscible flooding in a hypothetical target oilfield is examined. The major costs, including Windfall Prof it Tax, are identified and their re1ative importance are discussed. The sensitivity of profit to important physical and economic variables is evaluated and discussed, including variance in oil recovery, oil price, injectant requirements, injectant cost, and capital requirements. Economic sensitivities to important development and operating decisions such as timing, Spacing, Slug size, and gas recycling are also analyzed. The Windfall Profit Tax (WPT) as it applies to gas miscible EOR projects is reviewed. The effect of WPT on each of the various project cases is analyzed and the effect of reduced WPT on remaining production from existing operations is evaluated. Tax implications are compared for integrated vs. "independent" controlled projects and the alternative of expensing vs. capitalizing tertiary injectants is also evaluated. The impact of the Net Income Limitation in reducing WPT. during early and late project life is determined and discussed.

Jan 1, 1982

THE Institute of Metals Division of the A. I. M. E. has joined with the American Society for Steel Treating and the American Welding Society in support of National Metal Week in Philadelphia, Oct. 8 to 12. Individual and joint technical sessions, plant inspection trips, and a general exposition to be held in Commercial Museum have all been arranged. With the coming of the Institute of Metals Division into the circle, the scope of the exposition has been broadened to cover non-ferrous metals, and exhibits of much interest are promised. Headquarters for the Institute of Metals and the American Society for Steel Treating will be at the Benjamin Franklin Hotel, and for the American Welding Society at the Bellevue-Stratford. The American Society for Steel Treating and the Welding Society will hold technical sessions each forenoon at their hotel headquarters. The Institute of Metals Division will hold sessions Tuesday morning and Wednesday and Thursday afternoons; that for Wednesday being a joint session with the American Society for Steel Treating. The latter society will hold independent afternoon sessions on Thursday and Friday. Registration and information desks will be open at the hotels throughout the week, and an attractive program of entertainments has been arranged.

Jan 1, 1928

By E. A. Holbrook

IN view of what has happened in - the past three years, it seems incredible that industrial corporations continue to write to engineering and mines schools for "promising members of the graduating class," or, indeed, that they even send representatives to the colleges to interview engineering graduates. Certainly, by this time, every company should be aware of the fact that recent engineering graduates are almost nonexistent and the number is not likely to increase within the next several years. At the February, 1945, annual meeting of the Local Section delegates of the A.I.M.E. in New York, W. B. Plank, professor of mining engineering at Lafayette College, summarized well the situation of the colleges by titling his talk "The Lost Generation of Engineers."

Jan 1, 1945

By V. F. STANLEY

THERE is not the slightest doubt that the present recoveries of valuable minerals by the Broken Hill mills could be improved, and that further machinery would be installed for the purpose if it could be assured that a high price of metals would be maintained; but concentration, like all other com¬mercial propositions, is a question of profit and loss, and no sensible metallurgist would carry out his work in such a manner as to obtain high recoveries at a financial loss to his company. There is a point in all concentration at which the added money obtained from the higher recovery of minerals is balanced by the extra cost of obtaining the last part of the recovery; a wise metallurgist will be content with his work before his working-expenditure reaches this point. To a casual observer, the work being done by the various Broken Hill mills is identically the same. A closer investigation will show that this is far from being the case, for it is a remarkable fact that, although the larger mines extend over a length of approximately only 2 miles, such a difference in the physical and chemical properties of the ores exists that, from the first reduction downwards, special treatment is necessary in each case, and hardly any two mills are identical in operation. The details of this paper refer directly- to the work of one . particular mill in Broken Hill, for the reason that the ore from each mine presents special difficulties and requires its own special treatment. I have selected the mill referred to because it has been constructed and modified under my supervision.

Sep 1, 1909

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 M. R. Geer, H. F. Yancey

Four coals were treated in the Humphreys spiral concentrator, and the products were examined by float-and-sink and screen-sizing tests to determine fundamental performance characteristics. The efficiency of the separation between coal and impurity was shown to be influenced greatly by particle size.

Jan 1, 1950

By Nathaniel Herz

PARTING of bullion before shipment to the mint had been considered by the Homestake Mining Co. at various times, but had never been attempted before 1933, be- cause the margin of profit appeared to be too small to warrant the complications in refining. When the gold standard was abandoned by the United States in the spring of 1933, however, parting of the bullion was decided upon. The method selected was the Miller or chlorine process, which consists of the passing of gaseous chlorine into a bath of molten bullion, converting all metals other than gold into chlorides, and remov-

Jan 1, 1935

By G. A. Beiswenger

The application of the law of supply and demand to the sale of crude oil is generally conceded, but the motives underlying the buyer's (refiner's) demands are not always obvious to the seller (producer). In some cases this obscurity has led to the conclusion that the refiner may be unnecessarily particular when he selects one crude and rejects another. This preference, however, is very largely the reflection of the refiner's product demands and the quality of the stocks obtainable from the selected crude. The purpose of this paper is to point out critical characteristics of the major classes of refined products and to show how crudes vary in their suitability for such products. With relatively few exceptions, available processing methods and addition agents make it theoretically possible to produce any type of refined product from any crude source, although it may not be economi-cally sound to do so. The widespread application of thermal cracking for converting higher boiling stocks into gasoline is well known. More recently cracking and refining in the presence of catalysts9 have been developed, as well as various processes for polymerizing lighter hydro-carbons into gasolines having desirable characteristics.6 For several years, selective solvents have been applied commercially to refining inferior quality kerosene, Diesel fuel and lubricating oil distillates .3 Improved methods for refining lubricating oils from crude residua,4 formerly suitable only for fuel, are now in use and a number of special solvent processes are available for dewaxing lubricating oils to low pour point.5 These improved refining methods have been developed not only to meet the demand for improved product quality but also to enable the refiner to obtain quality products from crude sources that would not yield such products by the older refining methods. In many cases, the utilization of these modern refining tools necessi-tates an appreciable expenditure for equipment as well as added manufac-turing costs, and their application therefore must be justified economically. Despite the availability of such tools, the added processing costs involved and yields obtainable may render their application entirely impractical. To illustrate this point, inspections of typical cuts from various crudes

Jan 1, 1940