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February 18th, 1873. THE Institute assembled in the Hall of the Boston Natural History Society on Tuesday evening. Dr. T. Sterry Hunt, of the Boston Institute of Technology, after a brief address of welcome to the Institute, read an introductory paper on the Geognostical History of the Metals. President Raymond responded to the welcome of Dr. Hunt. The following names were then presented to the Institute, with the recommendation of the Council, for election Adams, J. M., - Silver City, Idaho. Daggett, Ellsworth, - Salt Lake City, Utah. Geist, Alfred W., - Boston, Mass. Hays, Dr. S. Dana, - Boston, Mass. Heinrich, Oswald J., - Midlothian, Va. Johnson, J., - Braidwood, Ill. Leckie, Robert G., - Actonvale, Canada. Lyman, Edward, - Troy, N. Y. Maltby, William, - Braidwood, Ill. Nichols, Lyman, Jr., - Boston, Mass. Ordway, Prof. J. M., - Boston, Mass. Rand, Theodore D., - Philadelphia, Pa. Richards, Prof. Robert H., - Boston, Mass. Rockwell, Prof. Alfred P., - Boston, Mass. Roepper, Charles W., - Bethlehem, Pa. Schulz, A. von, - Central City, Colorado. Singer, William F., - Pittsburgh, Pa. Spillsbury, E. G., - New York. Wells, Calvin, - Pittsburgh, Pa. The session concluded with the reading and discussion of a paper, by Henry Engelmann, On the Mines and Ores of the Little Cottonwood Canyon, Utah. The second session was held on Wednesday morning, when the following papers were presented; On the Midlothian Coal Mines, by Oswald J. Heinrich. On the Probable Existence of Microscopic Diamonds in California, by Prof. Benjamin Silliman.

Jan 1, 1873

T. R. HARRISON, Washington, D. C. (written discussion *).-Ad-vantage will be taken of this occasion to mention briefly a form of double potentiometer which has been used at the Bureau of Standards for about 2 1/2 yr. in calibrating thermocouples. The calibrations referred to are those made by comparison to standard couples. In order to insure equality of temperature between the couples, the junctions are fused together; consideration of fundamental principles will show that this introduces no error. Two separate potentiometers are used, one connected to each thermocouple, and each potentiometer is provided with a reflecting galvanometer. The two spots of light are reflected on to a single scale, the galvanometers being set in such a position that the spots coincide on the scale at a point marked zero when the circuits are open or when the potentiometers are balanced. By setting one potentiometer to a desired value and adjusting the other so that both spots pass across the scale together as the temperature rises or falls, simultaneous readings are obtained. By making observations first with a rising temperature and then with a falling temperature, the rates of rise and fall being approximately equal, and taking the means of the results found, several minor errors such as those clue to differences in the time lags of the two systems, etc., are eliminated or greatly reduced. The differences between the values

Jan 12, 1919

By Charles E. Locke

IN gathering material for this review the aid of the individual members of the Milling Committee was invoked and the assistance received is hereby most grate- fully acknowledged. The replies were much alike; almost everyone stated that in 1932 his operations had been cur- tailed or stopped entirely, that the only activity and progress were in milling gold ores, and that the Hadsel mill' looked like a coming machine in the crushing and grinding field. However, further inquiry and search have shown that the year was not quite so barren of developments as the foregoing statement would indicate.

Jan 1, 1933

H. Van F. Furman, Denver, Colo. (communication to the Secretary): There are some statements in Dr. Carpenter's interesting paper which appear to require explanation, if not modification.

Jan 1, 1901

By W. C. Leslie

W. C. Leslie (Edgar C. Bain Laboratory for Funda mental Research)—This investigation, with its com bination of high-purity metal, calorimetry, and metallography, will serve as a model for annealing studies for a long time to come. The evidence for a competition between recovery and recrystalliza-tion is particularly convincing. The demonstration of edge-nucleated recrystallization was so clear that it may obscure the necessity for other types of "nucleation" sites; otherwise, single crystals of aluminum could not be recrystallized after cold work. At least three types of sites have been found to operate in iron: 1) high-angle boundaries, probably in the same manner as in aluminum, 2) matrix sites, 3) inclusions or second-phase particles. In each instance, the cells developed during cold work and perfected during recovery are the "nucle for recrystallization. Observations by ourselves and others of the dislocation structure of cold-worked metals and of the structural changes that occur during annealing have led us to doubt the validity of the basic assumption of the Lucke-Detert theory, and of the modification developed by Gordon and Vandermeer, that during recrystallization of a metal containing foreign elements in solid solution a high-angle boundary is ad vancing into a cold-worked matrix having a random distribution of solute atoms. We contend that an es sential part of the cold-working and annealing of solid solution alloys is the trapping of solute atoms by the low-energy "wells" afforded by individual dislocations and by dislocation arrays. If cells are formed during cold work, the cell walls are stabilized by this concentration of solute atoms. Thus, solutes inhibit recrystallization not only by decreas-ing the rate of high-angle boundary migration, but also by preventing the formation of high-angle boundaries by subgrain growth or coalescence, i.e., solutes can inhibit both "nucleation" and growth. In addition to stabilizing the dislocation Structure, the solute-dislocation interactions may produce clusters of solute atoms which are not as readily assimilated into the recrystallized grains as are individual solute atoms. There is an additional complication. The dislocation structure formed upon cold working a dilute solid solution may not be the same as that formed during cold working of the pure solvent metal. The solute can either enhance or minimize the formation of cells during cold working. Both effects have been observed in binary alloys of iron. The annealing process is inextricably connected with the mechanisms of strain hardening and solid solution hardening. Although the correlation between experimental boundary migration rates and the predictions made from the theoretical equations are impressive, it should be mentioned that in at least four other instances (Pb-Ag and pb-Au,15, Fe-Mn,16, Fe-Mo)17 the agreement was rather poor. In brief, while it is probable that the migration of high-angle boundaries is held back by solutes in the manner described, this is only a partial explanation of the total effect of solutes upon recrystallization of cold-worked alloys. Paul Gordon and R. A. Vandermeer (author's reply)— The authors first wish to thank Dr. Leslie for his compliments of this work. It is perhaps worth pointing out that some of Dr. Leslie's remarks are directed toward subject matter covered in two earlier papers in our work.18,19 We agree with Dr. Leslie's main contention that the exact nature of the metal structure in the vicinity of a boundary should have an effect on the boundary migration. The theory of Lucke and Detert does not take such detail into account, nor does it account for orientation effects on the migration rates. We assume that since our data checks the theory so well, the effects of detailed structure are statistically averaged out by the polycrystalline techniques used just as are the effects of orientation factors.

Jan 1, 1963

By Henry M. Howe, Joseph Winlock, Francis B. Foley

This investigation was undertaken for the purpose of determining, in a systematic way, the effect of the rate of cooling of steels, heated to above the transformation range, on their various mechanical properties. This paper gives the results obtained in the investigation of the heat treatment of carbon steels carried out under the auspices of the Committee on The Heat Treatment of Carbon Steels of the Engineering Division, National Research Council. The objects of this committee, of which Dr. Henry M. Howe was chairman, were to increase knowledge of the influence of heat treatment on the mechanical properties of carbon steel. The mcthod pursued was to subject specimens of steel of the carbon contents most used for engineering work, 0.34 per cent., 0.52 per cent., and 0.75 per cent., to various heat treatments, and to test the mechanical properties thus induced. The steels were the same as were used by the committee on fatigue phenomena. This project was financed jointly by the U. S. Bureaus of Mines and Standards; industries and university laboratories have cooperated. A large part of the work was done at Doctor Howe's private laboratory. The committee consisted of F. B. Foley, H. AT. Boylston, H. C. Boynton, G. K. Burgess, H. J. French, J. H. Hall, Zay Jeffries, R. S. Johnston, F. C. Langenberg, H. F. Moore, E. H. Yeirce, H. S. Rawdon, W. E. Ruder and 11. J. Stagg. The work was undertaken at the suggestion of Doctor Howe, who thought, at the outset, that steel in the sorbitic state might have properties which, for most engineering purposes, would be better than those of the usual or pearlitic state. By a systematic variation in the heating

Jan 1, 1923

By Joseph Winlock, Francis B. Foley, Henry M. Howe

This investigation was undertaken for the purpose of determining, in a systematic way, the effect of the rate of cooling of steels, heated to above the transformation range, on their various mechanical properties. This paper gives the results obtained in the investigation of the heat treatment of carbon steels carried out under the auspices of the Committee on The Heat Treatment of Carbon Steels of the Engineering Division, National Research Council. The objects of this committee, of which Dr. Henry M. Howe was chairman, were to increase knowledge of the influence of heat treatment on the mechanical properties of carbon steel. The mcthod pursued was to subject specimens of steel of the carbon contents most used for engineering work, 0.34 per cent., 0.52 per cent., and 0.75 per cent., to various heat treatments, and to test the mechanical properties thus induced. The steels were the same as were used by the committee on fatigue phenomena. This project was financed jointly by the U. S. Bureaus of Mines and Standards; industries and university laboratories have cooperated. A large part of the work was done at Doctor Howe's private laboratory. The committee consisted of F. B. Foley, H. AT. Boylston, H. C. Boynton, G. K. Burgess, H. J. French, J. H. Hall, Zay Jeffries, R. S. Johnston, F. C. Langenberg, H. F. Moore, E. H. Yeirce, H. S. Rawdon, W. E. Ruder and 11. J. Stagg. The work was undertaken at the suggestion of Doctor Howe, who thought, at the outset, that steel in the sorbitic state might have properties which, for most engineering purposes, would be better than those of the usual or pearlitic state. By a systematic variation in the heating

Jan 1, 1923

By Wayne P. Myers

Electricity, as normally thought of by a layman's definition, is a manmade force that has no color, no odor, is not visible, cannot be heard, yet man can control it and make it perform his work for him. A person dare not cheat on it, for it then will master him. It has laws, rules, and regulations that must be strictly adhered to if it is to perform in the safest, most reliable, and economical manner. In the early days of coal mining the power source was man himself. Later man employed steam and compressed air to reduce his muscle power requirements needed in the extraction of coal. By the turn of the 20th century, electricity had become the most common source of power for the coal industry. Steam and compressed air are still found in use in isolated cases today for specific applications; however, they are rapidly being replaced by electricity. Electrical laws and regulations are quite extensive and somewhat complex for the proper generation and use of electricity. Man-made laws, rules, and regulations for the care and handling of electricity, designed for man's safety, are rigidly enforced by the U.S. Bureau of Mines, as well as the various state departments of mines. BACKGROUND Until recent years most underground coal mines used direct current exclusively for all movable and for some stationary equipment. Exceptions were for permanent pumps, tipple, fan, and outside buildings where alternating current was normally employed. However, over 60 years ago there were mines with dual systems. Alternating current was used for cutting machines, drills, and pumps, direct current for locomotives. There were no other machines as these were hand-loading mines. Later, during early mechanization in the 1920s, alternating current was also applied to loading machines at some mines. Use of dual electric systems then declined until fairly recently when

Jan 1, 1973

By W. J. Uren, Charles R. Kuzell

The industries engaged in winning minerals from the earth, because of their widespread dissemination, are faced with perhaps as wide a variety of labor-management problems as may be found in any other broad sphere of productive activity. Those problems are continually increasing in volume and complexity, and management has become aware of their growing importance. For the past quarter century at least, labor-management problems have largely been union-management problems. During this period tremendous assistance has been given labor unions through legislation and administrative and political action. In the United States, legislation favorable to unions has come about in the form of the now defunct National Industrial Recovery Act; the Wagner Act, most of which has been carried forward in the Taft-Hartley Act and the Landrum-Griffin Act; the Norris-La Guardia Act, the Wage and Hour Law, the Walsh-Healey Act, and others. The result has been to transfer from the hands of management to those who direct the affairs of the unions a large share of control over the industry and to hamper in many ways the remaining control left to management. In the United States there are many examples of the power of unions to injure whole industries seriously without regard to the interests of management, the employes, or the public. During 1958 and 1959 revelations of corruption and coercion in labor unions made before the McClellan Committee of the U. S. Senate generated considerable public sentiment in favor of legislation to protect the interests of employes and the public. However, the resulting legislation, the Labor-Management Reporting and Disclosure Act of 1959 (Landrum-Griffin Act), demonstrated quite clearly that the political power of the labor union leaders was adequate to prevent adoption of effective measures in this field.

Jan 1, 1964

By H. P. Greenwald

THE rapidly increasing use in coal mines of portable auxiliary fans, which are generally "blowers" employed in connection with canvas tubing, raises questions concerning the hazards of such equipment, especially where the practices are opposed to established methods of ventilating face workings. Half a dozen or more coal-mine explosions and some fires have been attributed to the use of auxiliary fans; moreover, competent mining engineers have found many dangerous installations and methods of use-for example, intermittent running of the fans in gassy mines with consequent accumulations of firedamp at the faces. These facts have led the U. S. Bureau of Mines to issue this recommendation: "In the interest of safety, the Bureau of Mines, Department of Commerce, recommends that auxiliary fans or blowers should not be used in coal mines as a substitute for methods of regular and continuous coursing of the air to every face in the mine." The comparatively recent introduction of new types of mining machines, mechanical loaders, face conveyors, and slabbing machines has encouraged the trial of new systems of face mining, all of which have for their object the rapid advance of the faces. Although the latter has certain economic advantages, in gassy mines the rate at which gas is given off is generally found to increase in proportion to the speed of advance into new territory, which in turn increases the difficulties of efficient ventilation of the face workings. Some of the systems of advance mining being tried in connection with new mechanizing methods practically compel the use of blower fans and tubing, as single narrow places are now driven, 300 ft. or more without crosscuts. In some instances a series of parallel headings are driven without crosscuts pre-

Jan 1, 1928

By S. F. Emmons

The history of the mining region of Custer county has been somewhat peculiar. Although, in the broader features of geological structure, it bears a strong resemblance to its newer and now more famous neighbor, 40 miles to the northward, the Cripple Creek mining district, it has been noted for failures rather than for successful mining ventures. Yet it has a number of mines that have proved themselves to be remarkably rich, and many others that have well-defined veins and very rich ore, though they never have been worked to any great depth. A few of the deposits seemed to the early miner so anomalous in form and manner of occurrence that they were popularly described as " contrary to all geological laws." The region has had several " booms," succeeded by more than usually violent reactions, the latter having proved more permanent than the former. It was, for a long time, the favorite resort of patent-process mongers, and the ground is now strewn with relics of various unsuccessful reduction-plants. Mismanagement, ignorance and disagreements among mine-owners seem to have been quite as responsible for the want of success in the region as the quality of the ores or the form of the deposits. In the early eighties, when the booms had not entirely died out, a division, then under my charge, of the U. S. Geological Survey, undertook an examination of the region for the purpose of making a study of its ore-deposits. The areal survey was carried to completion by Mr. Whitman Cross, but the study of the mines could never be completed for the reason that most of them were closed, for one reason or another, before we had time to visit them. From time to time, one or another of the important mines has been started up again, but it was not

Jan 1, 1897

By Harrison Everett Ashley

(Pittsburg Meeting, March, 1910.) Slimes are usually defined as all material passing a certain-sized sieve, which is invariably the finest sieve employed by each metallurgist in his tests; 100-mesh and 200-mesh have been taken as the limits by different writers in recent volumes of the Transactions ; 150-mesh is common practice. The reader of the first two volumes of Richards 1 is impressed by the inflexibility with which all grinding-arrangements are praised or condemned according as they make little or much slime. Until recently, one of the principal aims of the mill-man was to keep down the slimes. He was obliged to have separate apparatus for sand- and slime-treatment. The latter was sometimes puzzling and erratic. Often it was found most .economical to omit treatment of the slimes entirely, or to store them in immense basins or heaps, waiting for possible future improvements in methods of treatment. Recently, improved processes of agitation and filtration have made possible the successful extraction of values from many slimes. The tendency, when the metal is exceedingly finely disseminated, is to cut out all sand-treatment and to slime everything. These processes have been almost entirely mechanical in their conception, and it is the object of the present paper to show that certain chemical considerations may greatly hinder or assist their successful operation. It has long been a source of dissatisfaction to chemists that their analyses fail to be of much help to the clay-worker; that it is a matter of common occurrence for clays of closely identical ultimate chemical constitution to show the widest possible divergence in physical properties. * Published by permission of the Director of the U. S. Geological Survey. Ore Dressing (1903).

Aug 1, 1910

By C. E. Dobbin

THE identification of rock formations by a study of certain physical characteristics of burned samples was introduced in Wyoming in 1,926, when W. G. Buckles, superintendent. of the brick department of the Parco Development Co., reported to officials of the Producers & Refiners Corpn. that shales from the Cretaceous and older formations exposed between Parco and Rawlins exhibited distinctive coloration and textural features when burned in a standard brick kiln at temperatures ranging between 1000° and 3000° F. In collaboration with Elfred Beck, chief geologist of the Producers & Refiners Corpn., Buckles later burned cuttings and cores from several Wyoming wildcat wells in a standard kiln and successfully identified certain subsurface formations which had not been satisfactorily identified by other means. The results of their investigations were outlined in papers presented by Beck before the American Association of Petroleum Geologists at San Francisco in March, 1928, and by Buckles at. a joint meeting of the Rocky Mountain Oil and Gas Association and the Production Division of the American Petroleum Institute at Casper in November, 1928. These papers have not been published. The investigations set forth in this paper were carried out for. the purpose of determining the value of certain ceramic tests in assisting the petroleum engineers of the U. S. Geological Survey to identify well cuttings that represent Cretaceous shales penetrated beneath unconformable Tertiary formations in central, and eastern Wyoming, but that yield neither lithologic nor paleontologic criteria for satisfactory correlations with distinctive weathered outcrops. The investigations were made in the chemical laboratories of the Geological Survey at- Midwest, Wyo., and consisted of studying certain physical characteristics of burned bricks from representative outcrop samples of unweathered Cretaceous shales and of similarly burned cuttings of the same shales collected from wells in the Salt Creek oil field.

Jan 1, 1931

By H. P. Greenwald, H. C. Howarth

The rapidly increasing use in coal mines of portable auxiliary fans, which are generally 'blowers" employed in connection with canvas tubing, raises questions concerning the hazards of such equipment, especially where the practices are opposed to established methods of ventilating face workings. Half a dozen or more coal-mine explosions and some fires have been attributed to the use of auxiliary fans; moreover, competent mining engineers have found many dangerous installations and methods of use-for example, intermittent running of the fans in gassy mines with consequent accumulations of firedamp at the faces. These facts have led the U. S. Bureau of Mines to issue this recommendation: "In the interest of safety, the Bureau of Mines, Department of Commerce, recommends that auxiliary fans or blowers should not be used in coal mines as a substitute for methods of regular and continuous coursing of the air to every face in the mine." The comparatively recent introduction of new types of mining machines, mechanical loaders, face conveyors, and slabbing machines has encouraged the trial of new systems of face mining, all of which have for their object the rapid advance of the faces. Although the latter has certain economic advantages, in gassy mines the rate at which gas is given off is generally found to increase in proportion to the speed of advance into new territory, which in turn increases the difficulties of efficient ventilation of the face workings. Some of the systems of advance mining being tried in connection with new mechanizing methods practically compel the use of blower fans and tubing, as single narrow places arc now driven 300 ft. or more without crosscuts. In some instances a series of parallel headings are driven without crosscuts pre-

Jan 1, 1928

By Bevan Presley

THERE has been developed at Latouche a rather unusual system of mining which, for want of a better name, has been called the "Latouche system of mining." It is a modified form of shrinkage stoping applicable to orebodies of large or fairly large size where the ground is such that timbering would not be required in stoping. Mention has been made of this method of mining by Birch,1 who gave no details as it had been in use only a short time and the final outcome undetermined. The system, however, has proved to be entirely successful and it is thought that a paper covering it might be of general interest. Before proceeding with a detailed description of the "Latouche system" a brief description of the property and the various mining methods previously used will be given. LOCATION The Beatson mine of the Kennecott Copper Corp. is situated on the west coast of Latouche Island-, in Prince William Sound, Southwestern Alaska, 45 miles east of Seward, the coast terminus of the U. S. Government Railroad. It is a regular port of call for ships on the Southwestern Alaska run. The island is about 12 miles long and 3 miles wide. A ridge of mountains runs the entire length with a maximum elevation of 2500 feet. CLIMATE Latouche has to contend with possibly the greatest amount of precipitation on the North American continent. The annual average precipitation for the past 4 years has been 188 in., with 248 in. for the year 1926. A rainfall of 4 in. per day is not uncommon. In the winter the thermometer rarely falls below +20° F. and the snowfall is usually heavy during the months of March and April.

Jan 1, 1927

By George B. Lee

DURING The Two Years In Which The New Reduction-Works Of The Copper Queen Consolidated Mining Co. Have Been In Operation At Douglas, Ariz., There Has Developed A Remarkable Condition In Regard To The Corrosive Action Of The Water Used To Cool The Jackets Of The Blast-Furnaces. Were It Not For The Many Contradictory Features, It Might Pass As One Of The Unavoidable Troubles Due To The Composition Of The Water. This Water, Obtained From Wells 600 Ft. Deep, Is Also Used In The Steam-Boilers, And Its Composition, As Shown By The Following Analysis, Does Not Indicate The Presence Of Any Ingredient Which Would Explain The Corrosion Grains Per U. S. Gal. Silica, 0.861 Iron Oxide And Alumina, 0.223 Calcium Carbonate, 0.2111 Calcium Sulphate, Magnesium Carbonate, Sodium And Potassium Sulphates, . 14.850 Sodium And Potassium Chlorides, 9.732 Sodium And Potassium Carbonate, 6.452 32.409 The Jackets Are Made Of Inner Plates 0.5 In. Thick And An Outer Plate I In. Thick, With 3-In. Stiffeners Between The Inner And Outer Plates. In From 10 To 12 Months The Inner Plates Have Been Reduced By Corrosion To A Thickness Of From 1/8 To 1/16 In., While The Outer Plate In The Same Time Is Reduced By Less Than 1/16 In., And The Stiffeners Show Very Little Corrosion. The Plates Are Pitted And Eaten Away In Some Places More Than In Others. There Is Practically No Scale Found On The Jackets, But When Cleaned Considerable Iron Oxide Is Found In The Bottoms. With An Action So Marked, Serious Trouble Would Be Expected In The Boilers, But, On The Contrary, A Recent Inspection By a

Mar 1, 1908

By James H. Hance

Several years ago the writer was connected with the Mint and Assay Service of the Federal Government as Assistant Assayer at the Salt Lake Assay Office. At that time cyanide bars formed approximately half of the bullion purchased by that office. Disagreement in valuat,ion between the producer and the office was not infrequent and to a lesser extent between the Assay Office and the Mint, this latter issue being soon obviated, however, by adopting uniform methods of sampling the bars. A nice problem seemed to offer itself for research and the writer began a series of experiments which were soon terminated, however, by his going into other work, and which he regrets have not since been completed. The results attained may suggest lines of approach to this problem and are, therefore, offered in this article. Frederic P. Dewey, Assayer of the Mint Scrvice, U. 5. Treasury, has had abundant opportunity to study this phase of metallurgy, and has published several articles relative thereto.1 In the last article cited Dewey quotes analyses of cyanide bullion similar in content to that with which the writer worked, and which show some of the variations met with. In the discussion of these papers,2 comparison has been made in terms of copper bullion, but to the writer this seems of questionable value. Copper bullion may resemble silver bullion, but its similarity to gold bullion with little or no silver content is another thing. The freezing-point diagram of Roozeboom, reproduced on page 881 of the discussion cited, is for the gold-silver series as stated. The original problem under discussion, however, is not this alloy but gold with base metals other than copper. As for the statement that the corners are the worst places or

Jan 1, 1916

By Richard Franchot

IN the inevitable conquest of the blast furnace by metallurgical science in the solution of the problem of how to make more and better iron or to burn less coke, or both, it is highly desirable first to find out why the efficiency of the furnace generally is no better than it is. The immediate need would seem to be a theory to account for the existing facts. Explanation for the quantitative results obtained in current practice has been strangely lacking. One reason for this may be found perhaps in the custom of think-ing of efficiency in terms of coke consumption. Before efficiency can be explained there should be a fairly exact knowledge of what it is. A statement of the pounds of coke used per ton of iron made may have value in indicating comparative results in smelting similar ores with similar cokes, but it tells very little of the efficiency of the operation. When the materials are different, one practice burning 1800 lb. may be less efficient than another using 2000 lb. A better measure is the pig and slag per unit of coke. What is needed is a specific description of efficiency as a' definite quantity having an exact meaning. Such description is afforded by expressing efficiencies in terms of the respective proportions of the fuel energy absorbed in and chargeable to the various actions known to be -taking place in the furnace. Concretely, the energy value of a pound of coke having 85 per cent carbon blown with air heated to 1200° F. is about 7650 lb.-cal. (13,770 B.t.u.). And the work done in smelting a pound of average iron from hematite, comprising reduction and melting with production of a half pound of free running slag from an equal weight of limestone,

Jan 9, 1926

By J. B. Morrow, D. H. Davis

THERE are two general approaches to the problem of increasing profits from an operation. One is to lower expense; the other is to raise income. Mechanical preparation of coal may be used for either purpose but a prudent consideration of many details must precede any decision lest the results be negative instead of positive. It is quite possible that any net gain will result from a combination of the two. Since mechanically prepared coal invariably is a better product qualitatively than a hand-picked coal from the same mine, it is a reasonable expectation that the customer will be willing to increase the producer's income by paying a higher price. Or there may be the possibility that a combination of mechanical mining plus mechanical cleaning will give a lower over-all production cost for the coal in the railroad car. More likely, there will be found a combination of these two factors. From the customer's point of view, the competitive delivered cost per B.t.u. considered in relation to such incidental factors as dust nuisance, handling properties, ash disposal, and ash fusibility determines what he will pay. In-a bulk tonnage such as coal, freight is a very considerable part of the delivered fuel cost, and obviously freight paid on incombustible ash has no economic attractions. INCENTIVE FOR CLEANING Coal is prepared in four major ways: l (1) by screening or sizing, (2) by mixing or blending, (3) by cleaning, including hand picking and mechanical cleaning, (4) by dustless treatment. By a combination of any or all of these methods, coal can be prepared to standard specifications. It is easily possible to have good cleaning and still get a poor final product because of faulty screening or mixing, while it is possible to produce a very acceptable product from mediocre cleaning if the coal is well screened and mixed.

Jan 1, 1950

By Be Van Presley

There has been developed at Latouche a rather unusual system of mining which, for want of a better name, has been called the "Latouche system of mining." It is a modified form of shrinkage stoping applicable to orebodies of large or fairly large size where the ground is such that timbering would not be required in stoping. Mention has been made of this method of mining by Birchll who gave no details as it had been in use only a short time and the final outcome undetermined. The system, however, has proved to be entirely successful and it is thought that a paper covering it might be of general interest. Before proceeding with a detailed description of the Latouche system a brief description of the property and the various mining methods previously used will be given. Location The Beatson mine of the Kennecott Copper Corpn. is situated on the west coast of Latouche Island, in Prince William Sound, Southwestern Alaska, 45 miles east of Seward, the coast terminus of the U. S. Government Railroad. It is a regular port of call for ships on the Southwestern Alaska run. The island is about 12 miles long and 3 miles wide. A ridge of mountains runs the entire length with a maximum elevation of 2500 feet. Climate Latouche has to contend with possibly the greatest amount of precipitation on the North American continent. The annual average precipitation for the past 4 years has been 188 in., with 248 in. for the year 1926. A rainfall of 4 in. per day is not uncommon. In the winter the thermometer rarely falls below +20° F. and the snowfall is usually heavy during the months of March and April.

Jan 1, 1928