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INDEX TO TRANSACTIONS After a delay of many months, which is very much regretted, but which, it is hoped, will be one means of insuring a volume of accuracy where accuracy is very important, the Institute now has for distribution copies of the index of Volumes XXXVI to LV, inclusive. This is more than a mere index off names of authors and titles of papers. Every important topic under consideration by author or discusser is introduced under such key-word as will enable an engineer to locate the desired information with the minimum expenditure of time. This index sells for $5* in half morocco binding and $4*. in paper covers. With the index of Volumes II to XXXV (which sells for $5 in half morocco and $4 in paper covers), it forms a complete index of the first fifty-five volumes of the Institute's Transactions. These collective indexes are very valuable to members of the Institute, enabling them to look up matters in their own library; if they have the volumes to which the indexes refer, they can get the information at once, and, if not, they can readily determine whether or not a visit to a nearby public library is desirable.

Jan 7, 1918

By J. J. Bodmer

Although the similarity between puzzolana, or trass, and blastfurnace slag, as seen by comparison of the analyses, is a well-known fact, blast-furnace slag has not been used commercially as a substitute for those cementing materials. The reason, the writer apprehends, lies in the fact that unless such slag is disintegrated or subdivided by rolls, the process must either be too costly, or the material is not in a fit and proper condition for the purpose. In order to produce a reliable slag cement, the slag must be ground together with the lime into an impalpable powder. The subdivided slag must, therefore, be perfectly dry, and, at the same time, friable. The stronger the hydraulic properties of the lime, the more reliable the slag cement will be, and practice has proved, that the slag from a gray-iron furnace gives the best results. The slag cement which has given the results shown in the annexed table, under pressure tests, was composed of six parts of slag, from a blast-furnace producing No. 3 foundry iron, and one part of lime, of medium hydraulic properties. The above-described class of cement bears storing as long as most Portland cements, and the cheapness of its production is self-evident.

A permanent exhibition of mining machinery has just been opened in the Grand Central Palace, New York City. The exhibits include: Aerial tramways, amalgamation, assaying and laboratory appliances and supplies, blast furnaces, coal, coal-breaker plant, coal excavation, coal products, compressed-air plant, concentrating, crushing, cyanidation, distillation, drainage and pumping, drilling, earth excavation, electrical supplies, explosives, fire prevention, flotation, general supplies, hoisting, hygiene, welfare, iron products, leaching, mechanical conveyors, metal products, natural gas, petroleum, petroleum products, electric, steam, hydraulic, gas, air, and internal-combustion engines, power machinery, preparation of coal, pumping, refining, roasting, rock excavation, rotary drilling; boring, safety appliance, screening and washing, sizing and classifying, smelting, storage of coal, storage of petroleum, surface transportation, surveying, underground timbering, underground trans-port, ventilation, mine. This exposition is operated by the Merchants and Manufacturers Exchange of New York for the purpose of showing under one roof all lines of machinery and mechanical appliances. As for as possible, the exhibits will be shown in operation. The Advisory Committee is as follows: General Howard R. Ward and H. C. Parmelee. Coal and Coke.-Prof. H. H. Stoek, Samuel A. Taylor, Edwin Ludlow. Petroleum and Gas.-Frederick G. Clapp, Ralph Arnold.¬ Extraction of Metals.-Charles W. Merrill, E. Gybbon Spilsbury. Refractories.-Kenneth Seaver.

Jan 12, 1919

By J. J. Bodmer

ALTHOUGH the similarity between puzzolana, or trass, and blast-furnace slag, as seen by comparison of the analyses, is a well-known fact, blast-furnace slag has not been used commercially as a substitute for those cementing materials. The reason, the writer apprehends, lies in the fact that unless such slag is disintegrated or subdivided by rolls, the process must either be too costly, or the material is not in a fit and proper condition for the purpose. In order to produce a reliable slag cement, the slag must be ground together with the lime into an impalpable powder. The subdivided slag must, therefore, be perfectly dry, and, at the same time, friable. The stronger the hydraulic properties of the lime, the more reliable the slag cement will be, and practice has proved, that the slag from a gray-iron furnace gives the best results. The slag cement which has given the results shown in the annexed table, under pressure tests, was composed of six parts of slag, from a blast-furnace producing No. 3 foundry iron, and one part of lime, of medium hydraulic properties. The above-described class of cement bears storing as long as most Portland cements, and the cheapness of its production is self-evident.

Jan 1, 1874

[ ] TUNNELS TO BINS. Originally designed for tunnel work, the strong lightweight liner plates used to construct this 30-ft diameter, 31-ft high, aggregate storage bin have several advantages. Bins and conveyor to tunnels can be quickly erected in any season, for permanent service, or to be salvaged and reused. Armco Steel Corp. (16) ROLLER CHAIN: Engineering Data Book No. 2457 published by Link-Belt Co. is a comprehensive 148-page volume on roller chain and its application. Detailed engineering information covers installation, maintenance and lubrication of chains for drives, conveyors, and sprocket wheels. The book covers selection of drives to meet both standard and special installations. (17) LABORATORIES: The Fisher Scientific Co's. line of 21 basic units of standardized steel laboratory furniture is described in catalog no. 25. The Unitized line was designed to combine the advantages of custom installation with the convenience of selection, delivery and continued flexibility that goes with ready-made units. (18) PUMPS: Two similar, but functionally different types of vertical centrifugal wet-pit pumps; a heavy duty bilge pump for handling solids-free liquids and drainage; and a screenless sewage ejector, constructed to handle sewage and solids carrying liquid; are illustrated in a bulletin from Yeomans Bros. Co.

Jan 1, 1952

POSITIONS VACANT (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) Superintendent for iron mine operated on the sub-level and caving system. Small output, moderate salary. Location, Southern State. No. 45. Chemist to sample and analyze iron ore. Experience in other branches not essential. Location, Southern State. No. 46. ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introducd by members.) Experienced mine superintendent desires position. Several years' experience in practical management of mining and development work. Has also practiced ass consulting engineer and is thoroughly experienced in the examination and development of mining properties. Mexican experience. Will go anywhere for reliable concern. Salary moderate. References. No. 254. Member, mechanical superintendent, wants position. Has had 12 years' experience as master mechanic of smelting plants in United States and Mexico. Also superintendent of shops doing marine, mining, and general contracting work. . Experienced in manufacture of mining tools and equipment. Up to the minute in copper, lead, and zinc smelting. Has learned a learned a great deal, can forget much, and has the inclination and ability to learn more. Best of references. No. 255.

Jan 10, 1915

POSITIONS VACANT Position as superintendent of all-sliming cyanide plant in Montana will he open in spring. Thoroughly experienced man wanted. No. 6. Position as engineer for iron-mining company in Virginia is open. Single man with experience in underground surveying preferred. No. 7. ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute. by members or other persons.) Member, 34 years old, married, nine years responsible position in South America, excellent knowledge of Spanish, Latin-American people and customs, with present employer seven years, six years as manager and legal representative of a mining company, desires to make a change April, 1914. Prefers position requiring energy, executive ability, business tact and practical knowledge dealing with political and legal authorities, rather than strictly technical position. No. 35. Technical graduate, married, with four years' experience in assaying, surveying, sampling,. and mine supervision in Utah and Mexico, open for engagement. No. 37. Member, aged 28, desires opening on engineering or sales force of machinery house, or manufacturing concern. Twelve years' experience, in smelters, cyanide plants, concentrators and gold dredges, steam, gas and electric machinery and mechanical drafting. At present foreman for a silver-lead company. No. 40.

Jan 1, 1914

The School of Mineral Industries is dedicated to education in mineral conservation and research by which the means may be found to make conservation effective. This includes diligent search for mineral truths and the energetic discovery, complete recovery, and maximum utilization of irreplaceable mineral resources. Standards of living depend upon two factors: human resources-intelligence, imagination, initiative, know-how, work; and natural resources-plants, animals, and minerals, including water, air, soil, heat and light from the sun, and all other such resources that are useful to man. Human relationships have not kept pace with scientific achievement; as a result man, in desperation, wittingly, premeditatively sacrifices freedom for security. Many natural resources, through overproduction, mismanagement, and greed, have definitely moved over into the exhausted or exhaustible category. The United States cannot maintain present standards of living on an agricultural economy alone, and serious harm can ensue if there are marked disproportions in numbers and relationships between city and rural populations. The most materialistic New Yorker must see virtue in bucolic loveliness. The United States is rated wasteful and inconsistent most of the time. It does not make sense to dole out through the keyhole what a wage earner can bring through the open door; to raise wages to lower the cost

Jan 1, 1950

By Thomas V. Falkie, Robert Stefanko

Previous articles in this column have defined the manpower situation as it. applies to the coal industry. There is at present a shortage of experienced managers, mining engineers, technicians and skilled workers. The extent of this shortage is controversial, but it is sufficiently important to have received the serious attention of coal industry people at all levels. It has also been discussed by union officials, educators, government agencies and trade publications as well as other communications media. Discussion is not enough, however. A plan of action is needed. Some suggestions for such a plan are presented here. First, the coal industry must interest itself in government training programs. The U.S. Government (primarily the Bureau of Mines and HEW) is planning to spend or is spending millions of dollars to educate and train technicians, inspectors, engineers and miners. The new Federal Health and Safety Academy at Beckley, W. Va., for example, will involve an expenditure of $20-30 million for the physical plant alone. There are encouraging signs that the present hierarchy in the Bureau of Mines intends to seek the advice of mining educators on some of these projects, but industry should also demand a voice in the policy to be followed in making these expenditures.

Jan 1, 1971

By R. H. Wightman, G. H. Adams

H. C. WEED*—Referring to the use of "dummy fuse" for checking the shots in chute blasting operations, I believe that an even better practice is to blast the chutes with no delay electric blasting caps. Permanent wires can be strung through the grizzly lines and the lead wires from the shots attached to these lines. Using this method, no time is lost in spitting the individual fuses. The possibility of a fused charge becoming dislodged by previous shots and falling into the chute below is eliminated and there is no chance of a man walking back into his own blast. A small hand twist blasting machine or a radio "B" battery can be used to fire the shots if the lines are fired individually. If so desired the entire area can be blasted at once by a switch at the manway or in the drift below. providing a sufficient source of electricity is available. In case a switch is used, proper precaution for locking the switch must be provided. R. H. WIGHTMAN (author's reply) —We do use electric blasting when the number of shots is large; but we have found it more satisfactory to use fuse and caps for individual shots on the grizzly.

Jan 1, 1950

By Reinhardt Schuhmann JR

Metallurgical Engineering Volume I, by Reinhardt Schuhmann, Jr. Addison-Wesley Press. $7.50, 390 pp., 1952. -This first volume, engineering principles, of a two volume work, is intended by the author to meet a need for reorganization of instruction in extractive metallurgy. Its three main objectives are to organize the subject matter according to basic principles and unit processes; to integrate the underlying science of physical chemistry with metallurgical engineering; and to put greater emphasis on analysis and quantitative solution of engineering problems. Vol. I deals with unit processes, stoichiometry, thermodynamics, fuels, fluid flow, heat transfer, pyrometallurgical systems and refractories. Vol. II will take up the individual unit processes. Initiation and Growth of Explosion in Liquids and Solids, by F. P. Bowden and A. D. Yoffe. Cambridge University Press. $4.50, 104 pp., 1952.-The book is a study of decomposition by impact and by friction of explosive substances and deals mainly with the work of the authors and their collaborators. Research is still in progress but results thus far indicate that the mechanism of initiation is relatively simple. Findings are thoroughly discussed, and the latter part of the monograph describes the way in which a small nucleus of decomposition can grow into a large scale explosion.

Jan 1, 1952

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 5 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and file this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. 11. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its Council; that the under- signed are all members of said Council as the same was constituted on the 29th day of December, 1904.

Jan 1, 1932

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 6 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and 6le this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. 11. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its Council; that the under- signed are all members of said Council as the same was constituted on the 29th day of December, 1904.

Jan 1, 1939

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 6 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and 6le this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. 11. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its Council; that the under- signed are all members of said Council as the same was constituted on the 29th day of December, 1904.

Jan 1, 1943

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 6 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and 6le this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. 11. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its Council; that the under- signed are all members of said Council as the same was constituted on the 29th day of December, 1904.

Jan 1, 1936

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, 8s provided in Section 5 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and file this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. II. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its Council; that the under- signed are all members of said Council as the same was constituted on the 29th day of December, 1904.

Jan 1, 1932

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 6 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and 6le this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. 11. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its Council; that the under- signed are all members of said Council as the same was constituted on the 29th day of December, 1904.

Jan 1, 1934

WE the undersigned, being all persons of full age and citizens of the United States and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 5 of Article I. of said law, the existing unincorporated association known as American Institute of Mining and Metallurgical Engi¬neers, Incorporated, do hereby make, acknowledge and file this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. II. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its Council; that the undersigned are all members of said Council as the same was constituted on the 29th day of December. 1904.

Jan 1, 1938

By H. Eklund, R. T. Hukki

This article presents a simple arithmetic derivation for the relationship between sharpness of classification and circulating load, as well as world-wide industrial data which are compatible with the derived equation. It is shown that the sharpness of classification decreases with increasing circulating load. Based on the evidence available a comparison is presented between the performance of the present-day hydraulic classifiers. In a continuously operated closed circuit grinding system the tonnage and the fineness of the components may be indicated as follows: Eq. 8 expresses the relationship between sharpness of classification and circulating load in closed grinding circuits. If CL = 0, E = 100% according to the definition used. This, however, is a purely theoretical case because any apparatus to be called a classifier must produce the conventional two products. Furthermore, if CL = m, E =0%. In order to visualize the meaning of Eq. 8, the effect of factors d (fineness or percentage of under-size of classifier overflow at size x) and b (fineness or percentage of undersize of classifier sands at size x) should be studied. By the most rigid standard, factor d should be given the value of 100%. By so doing the size of classification is defined as that screen size x through which 100% of the classifier

Jan 1, 1965

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 5 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and file this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. II. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its Council; that the under-signed are all members of said Council as the same was constituted on the 29th day of December, 1904.

Jan 1, 1934