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By C. H. G. Bushell, M. Malnarich

Reagent control in flotation is more an art than a science. Operators vary the amount of re- agents used according to the metallurgy obtained. The amount of collector may be increased, for example, if tailings losses are high and decreased if concentrate grades are low. Often control decisions are based on only one assay, such as the tailings analysis by microscopic or quick assaying techniques. This method of control has given reasonably satisfactory results but is clearly far from perfect. No adjustment in reagent addition can be made until information is received that metallurgy has deteriorated, that is, until the optimum time for adjustment has already passed. The first adjustment probably will be an overcorrection or an undercorrection, and time will be required to establish the best new addition rates. The seriousness of the problem depends on variability of the ore. In ore of continually shifting composition and complexity, mill results will shift back and forth from excessively high concentrate grades and high tailings losses to excessively low concentrate grades and low tailings losses. Economic incentive for improved control also increases with increasing size of mill. Even a small improvement in percentage recovery in a large mill pays for expensive control equipment.

Jul 1, 1956

By A. Springer

Chemists, physicists and others, whose occupations necessitate the use of fine scales, have heretofore regretted their inability to obtain any which would remain uniformly accurate. The difference between the theoretical and the actual results obtained in the ordinary balance (provided the pivot-distances are exact) is mainly due to the frictional resistance between the knifeedges and their bearings. This frictional resistance, although reduced to a minimum in the finest scales when new, constantly increases, thereby decreasing the sensitiveness proportionately. When examined under the microscope, neither the surface of the knife-edge nor that of' its hearings ever appears perfectly smooth. Soft kunife-edges are easily blunted, whereas hard ones are brittle and liable to crumble under the effects of over-load or shock. Prof. Frederick A. Roeder for many years attempted to discover some means by ,which the knife-edge could be replaced with some device free from the above-mentioned objections. His experiments convinced him that a torsion-joint was best suited for that purpose. After he had communicated his conclusion to me, we jointly developed the system to its present form. A torsion-wire had been used for the centre of rotation, prior to Prof. Roeder's invention, but it was found impossible to replace the terminal knife-edges with torsion-joints.

Jan 1, 1884

By Thomas J. O’Neil

From the time of its emergence as an independent state until the late 1950's, the Republic of Ireland suffered from chronic unemployment, the lowest living standard in Northern Europe, and-most serious of all-an aggravated emigration problem which drained off most of its talented young people. In 1958, however, there was a drastic legislative reaction to these problems, and this in turn ignited the current mining boom in Ireland. Paving the Way to Prosperity In order to reverse the tide of emigration, the Irish government now realized, challenging domestic employment opportunities had to be increased and living standards had to be raised. It was also apparent that future industrial and economic growth in Ireland had to be based on producing goods for export. The home market could not sustain large-scale expansion, and consequently Ireland's chronic balance-of-payments deficit could best be minimized by producing export goods. These considerations, together with the limited amount of accumulated wealth in Ireland, combined to set the objectives of the country's First Program for Economic Expansion in 1958. The general objectives of this program were (1) to stimulate all segments of the economy, (2) to develop foreign trade and (3) to attract foreign capital.

Jan 1, 1970

By Robert S. Shoemaker

Receiving the Richards Award is undoubtedly the most memorable event in my entire life. There should, however, be more names engraved on it. These are the names of men who were my teachers (but not all of the academic variety) and my friends, each of whom had a part in my ever continuing education and thus have a part of this award. There was Bill Caldwell who made me into a chemist, and Will Shorey who added a lot of ore dressing. There was Rush Spedden who put me to work in his minerals research lab, Joe Brennan who made me turn my research into plant practice, and Tom Meek who sent me all over the world on metallurgical jobs. Bob Cheatham and Abe Dor taught me to try to give the client what he needs rather than what he wants, while Ed Malouf and Casey Davis always gave their particular brand of advice at exactly the right time. And, lastly, there was Leo Abell and Frank McQuiston, both fine metallurgists and the best friends a man could have. In addition to those I have mentioned, there are literally scores of others I would like to acknowledge with my sincere appreciation.

Jan 6, 1974

By K. P. Wang, Virgil L. Barr

The U.S. Minerals Attaché Program, similar to the scientific and technical attache programs of other industrialized nations, is designed specifically to keep surveillance on significant worldwide developments in minerals, metals, and fuels. Knowledge of international minerals developments is essential for both domestic planning and conduct of foreign affairs. CONTROLLED BY DEPT. OF STATE Ten minerals specialists-eight minerals attaches and two petroleum attachés-man this far-flung, worldwide program for the U.S. Government as best they can. Minerals attach& also handle oil, in posts lacking petroleum attaché. The legislative authority for the Minerals Attaché Program is the Foreign Service Act of 1946 and succeeding amendments and Presidential Executive Orders. Therefore, this program is controlled by the Department of State. Interior (representing the Bureau of Mines) and State collaborate in policy formation and direction by means of a "memorandum of agreement" which covers establishment of posts, selection of officers, contents of reports, and supplemental training. State also has about half a dozen nonspecialist officers to complement the work of the minerals and petroleum attaché. It is not the intention here to evaluate the administrative arrangements of this program but rather to describe it and to provide examples of the important job it is doing.

Jan 11, 1965

By Howard M. Graff, Sidney C. Bouwer

The economics of mining has traditionally been viewed quite apart from the economics of blast furnace operations. It was realized, of course, that blast furnaces would operate best with good raw materials, but the shipping grade of ore, for example, was decided by a sort of collective bargaining process between the ore producers and the blast furnace operators. The mine operators had to keep their costs down, and were usually successful in convincing management that the ore in any particular deposit was endowed by nature with a certain iron content and that the mine grade could not be raised beyond a certain economic limit. The blast furnace operators would have liked a better grade, but as long as they were able to make a fairly good showing it was more or less accepted that they had to take the ore as it came. The mine operators were able to ship to the nation's blast furnaces thousands of tons of iron ore that would be completely unacceptable by present-day standards. As late as the early 1950's, the major steel companies were witnessing an actual decline in the iron content of their incoming ore supply as the mining companies mined progressively leaner material and upgraded it only enough to pass competitive market requirements

Jan 8, 1965

By William Hamilton Merritt

A brief paper on this subject (which might readily be made to, fill a volume) is suggested at this time by several considerations, among which may he named the meeting of the Institute on the borders of Ontario, not far from some of the mining undertakings which are hereafter mentioned ; the mineral developments made in the Province quite recently ; the highly creditable collection of most of the minerals of Ontario, for the first time got together, and exhibited this year at Cincinnati, in the Centennial Exhibition of the Ohio Valley ; and, finally, the recent appointment, by the Government of Ontario, of a Commiesion to inquire into, and report upon the mineral resources of the Province, and the best means to be adopted for their development. The Province of Ontario has no Department of Mines or official geologist, to take note, and keep record, of mining and mineralogical development and discovery. Within the last few years some valuable statistics have been collected by Mr. A. Blue, the Deputy Minister of Agriculture; but recently a desire has risen on the part of the people to obtain further knowledge of these subjects, and the government has appointed a Commission, the report of which is expected to be issued in part, if not in completed form, this winter.

Jan 1, 1889

For the first time, the attendance at the meetings of the Institute passed the thousand mark; as is shown by the following table: REGIS- AT BANQUET DID TOTAL TERED NOT REGISTER Men :..:... 703 76 806 Women 195 61 256 1062 The names of the members and guests who registered or attended the banquet but did not register are: A A. D. Beers C. A. Adams Hans Behr Thos. J. Adams Edgar G. Bell Lawrence Addicks Donald A. S. Bell H. T. Abrams W. de LeBenedict G. Aertsen G. B. Bertelli M. M. Albertson Charles P. Berkey James Aldrich Clinton Bernard D. C. Alexander, Jr. W. N. Best W. H. Alexander Robert M. Betts A. W. Allen Christopher H. Bierbaum F. D. Aller Paul Billingsley R. H. Allport R. A. Bingham F. C. Alsdorf R. M. Bird Capt. M. Altmayer John L. W. Birkinbine A.' W. Ambrose G. S. Bisey Henry M. Ami Charles W. Boise F. L. Antisell J. J. Blackmore R. S. Archer A. E. Blackwood Paul' Armitage Capt. C. K. Blatchly Andrew B. Armstrong E. L. Blossom Clifton T. Armstrong C. A. Bohn Ralph Arnold James M. Bonsall R. M. Atwater, Jr. E. E. Boon Joseph E. Aue Gail Borden A. M. Austin R. S. Botsford W. S. Ayres John M. Boutwell

Jan 4, 1919

By A. Bauer, P. Calder, N. H. Carr, G. R. Harris

Smallwood mine is part of the Iron Ore Company of Canada's Carol Lake operation and is situated in Labrador, 240 miles north of Sept-Iles, Quebec. Last year, 15 million tons of crude ore were crushed to yield 6.3 million tons of concentrate and pellets. This year the figures will be 17 million of crude and 7 ¼ million tons of concentrate and pellets, which is the full plant capacity. Carol Lake ores consist primarily of specularite and magnetite mixed with quartz. Since both rotary and jet piercing drills are used, it is often desirable in planning to know in which regions of the orebody, or new orebodies, a particular drill will be most economic. This makes it necessary to establish a correlation between drillability and pierceability and some physical rock property. For the rotary drills a good correlation was found with penetration rate and grinding factor index. The jet piercers were found to have a reciprocal relationship in the sense that the best rotary ground was the worst jet ground and vice versa. It is also indicated how an economic comparison could be made using these penetration rate versus grinding factor index curves, the hole size distribution curves for single pass and chambered holes, and the mine distribution curve for grinding factor index.

Jan 9, 1965

By H. E. Powell, A. A. Cochran, R. E. Coleman

Infrared spectroscopy, employing the internal reflection method in conjunction with solvent extraction techniques, was used to study surface reactions between aqueous potassium ethyl xanthate and both sphalerite and precipitated zinc sulfide, each activated with aqueous copper sulfate. It was determined that reactions occurring on the sphalerite and zinc sulfide surfaces produce the reaction products ethyl dixanthogen and cuprous ethyl xanthate, some of which are adsorbed on the mineral surfaces. As the pH of the xanthate solution increased from 5.6 to 11.0, the amount of cuprous ethyl xanthate on powdered sphalerite surfaces decreased and the amount of ethyl dixanthogen first increased and then decreased. It is generally accepted that the collector potassium ethyl xanthate will not float the mineral sphalerite (ZnS). However, Gaudin1 showed that sphalerite readily floats if activated with certain metal cations before exposure to the xanthate. Copper sulfate (CuSO4) was found to be the best activator for sphalerite. The over-all flotation reagent reaction, as given by Gaudin,3 is as follows: While this is the over-all reaction, the exact mechanism of the reaction and the intermediate compounds that may be formed are not yet known with certainty. Important work has been done in Russia by Plaksin

Jan 1, 1968

By O. Chanute

In discussion of Mr. Macdonald's paper, I can say little more thau to add t~ the general acknowledgments of iguorae, and like several of the gentlemen who have preceded me, make one of those confessions which are thought to be good for the soul. Having had some experience in the erection of bridges during past years, I am aware that We yet need much information in order to proportion them to the best advantage. I would more especially like to emphasize three of the points mentioned by Mr. Macdonald, as among those upon which we lack knowledge; these are: first, the behavior of steel; second, the proportions of compression members; and, third, the influence of the size of a bar upon its strength per square inch. First, as to steel. While we all acknowledge this as the material of the future, our position map be said to be still one of expectaucy. Feu? engineers are bold enough to employ it largely in bridges, and those who do, find such serious difficulties in obtaining uniform grades of it, are so puzzled by apparent anomalies and unexpected phenomena, that it requires considerable faith and courage to apply it in large structural masses. A series of systematic experiments,

Jan 1, 1882

Discussion of the paper of WALTER 0. SNELLING, presented at the New York meeting, February, 1915, and printed in Bulletin No. 100, April, 1915, pp. 695 to 704. A. F. LUCAS, Washington, D. C.-Are the results of the experiments in practical operation? WALTER 0. SNELLING.-There have been no large-scale operations up to the present. The necessary conditions of temperature are easily arranged for, but the required condition of pressure, 800 lb., is not so simple a matter. The company has been working on this problem, and at the refinery in Oklahoma work of this kind is now being carried on. The way in which an ordinary still will leak at 50 lb., and more at 100 lb., leaves some doubt in the mind of many as to what can be clone at a continuous working pressure of 800 lb. On the other hand, the fact that they are making ammonia abroad by a method which employs higher pressures and temperatures than anything involved in this method, leads me to believe that the difficulties, which will undoubtedly arise when this is attempted on a commercial scale, can be overcome. WILLIAM N. BEST, New York, N. Y.-Is there any change in the calorific value of these oils?

Jan 5, 1915

By John Birkinbine

The favor with which the members of the Institute received Mr. Fernow's paper upon the use of charbon roux in the manufacture of iron has encouraged me to present this paper, in the hope of having the discussion upon the manufacture and use of the oldest and undoubtedly the best fuel for producing pig iron continued. Owing to the advances made in employing anthracite coal, bituminous coal, or coke, or mixtures of them, we are apt to forget how much of our present development is due to the pioneers in iron manufacture and the fuel which they employed in the production of pig iron. In Mr. Swank's last compilation of the iron and steel works of the United States, the furnace capacity of the country is given as 5,868,000 tons, of which 1,000,000 tons can be made in the 264 charcoal furnaces. In other words, over one-third of the furnaces now in existence use charcoal for fuel, and produce more than onesixth of the iron made. If to this is added the 130,000 tons of blooms and billets turned out by the 122 forges and bloomaries, the importance of the charcoal industries will be appreciated.

Jan 1, 1879

By John Chipman, Donald W. Murphy

RECENT developments in iron alloys containing nitrogen have indicated that this element may exert a considerable influence on the properties of the metal. This influence is not always in an undesirable direction and the indications are that nitrogen should be regarded as an alloying element, the amount of which should be subject to control, rather than as an inherently deleterious impurity. In controlling this element in liquid iron to the best advantage, it is necessary to have a reliable background of fundamental data pertaining to solubilities, rates of solution and chemical reactions of nitrogen in liquid iron. Obviously, the first step in such an investigation is the determination of the solubility of nitrogen in pure iron, and this has been the object of the experiments described in this paper. The solubility of nitrogen in solid iron has been measured by Zurich,1 Sieverts,2 Martin,3 and Iwasé4 and, the agreement among the first three inspires confidence in their results. No accurate determinations of its solubility in liquid iron have been recorded though several investigators have obtained approximate results. Strauss5 was able to introduce 0.03 to 0.04 per cent nitrogen into steel by the action of either ammonia or nitrogen on the liquid metal. This was accomplished by Eilender and

Jan 1, 1935

By S. Oglesby, A. L. Thomas

Until recently, probably the best means of sampling airborne dusts has been the impinger method. Dust-laden air is drawn into a sampling tube, and the particulate matters separated from the air and collected in the liquid in the impinger. A sample of the suspension is prepared on a slide and counted through a projection microscope. This method is simple and reliable, but it does suffer drawbacks. Since the collected particles must be counted visually, results of the dust count are not immediately available at the time the sample is taken. This seriously impedes studying the effectiveness of dust inhibitors, such as water sprays, or making adjustments in equipment. Greatest disadvantage of all, however, is the tedious task of counting particles in the sample. With the growing desirability of taking more samples, the effort involved in making these counts is a real factor in the cost of dust control. Finally, it is generally recognized that impinger dust counts can be related to health hazard only for specific kinds of dust and under similar conditions. This is because the rather complex mechanism of dust damage depends so much on size distribution of the dust. Counts determined by impinger samples cover a limited size range that does not necessarily corre-

Jan 1, 1960

By B. J. Kochanowsky

To improve blasting methods it is necessary to know how the explosive force acts and how rock resists this force. Because of the tremendous power developed within milliseconds and the great number of other factors directly affecting the technical and economic results, an analysis of the fundamentals of blasting theory is difficult. But since the rules used for layout design and for calculations of size of explosive charges are based on theoretical assumptions, complete knowledge of blasting theory has great practical importance in mining. Analysis of Blasting Theory: It is interesting to note the opinion of blasting experts with respect to contemporary blasting theories. F. Stussi,' Professor of the University of Zurich, stated: "We do not have enough experience yet to change our army engineering regulations in blasting and base it on new fundamentals. It is our duty to collect more practical data and to do more research in blasting to close this gap." K. H. Fraenkel,' editor of the Manual on Rock Blasting published in 1953 in Sweden and written by well-known Swedish, German, Swiss, and French blasting and explosive experts, said: "To the best of our knowledge no suitable formulas for civil blasting work are to be found in the American, French or German literature."

Sep 1, 1955

By John Birkinbine

THE favor with which the members of the Institute received Mr. Fernow's paper upon the use of charbon roux in the manufacture of iron has encouraged me to present this paper, in the hope of having the discussion upon the manufacture and use of the oldest and undoubtedly the best fuel for producing pig iron continued. Owing to the advances made in employing anthracite coal, bituminous coal, or coke, or mixtures of them, we are apt to forget how much of our present development is due to the pioneers in iron manufacture and the fuel which they employed in the production of pig iron. In Mr. Swank's last compilation of the iron and steel works of the United States, the furnace capacity of the country is given as 5,868,000 tons, of which 1,000,000 tons can be made in the 264 charcoal furnaces. In other words, over one-third of the furnaces now in existence use charcoal for fuel, and produce more than one-sixth of the iron made. If to this is added the 130,000 tons of blooms and billets turned out by the 122 forges and bloomaries, the importance of the charcoal industries will be appreciated.

Jan 1, 1879

By Edward H. Robie

IN many ways, the Annual Meeting of the Institute in February was the most successful yet held. Attendance surpassed even that of the 75th Anniversary Meeting in 1947 with its international flavor. The number of technical sessions and the number and quality of papers presented almost certainly set a new record. The banquet was the best attended of any yet held even though the price reached a new high. Despite the demand for almost 1700 tickets to the banquet, some felt that the price-$13.50-was higher than they could afford. There are two points of view: One is that this is the big social event of the year for members and that it is worth from three to five dollars more to have it at the Waldorf and to have a luxury menu, as we did this year, with turtle soup, a fish course, guinea hen for the entree, and wild rice (which we understand is $3.50 per lb) for a vegetable. The other point of view is that a seven or eight dollar banquet of more simple food at the Commodore Hotel would more than make up in appeal, especially to the younger and less well-heeled members, what it would lack in glamour.

Jan 1, 1952

By James J. Scott

INTRODUCTION This paper presents the basic principles which must be followed to create a truly inherently safe mining system. The need to relate the support mechanism to be employed to the ground reaction curve and basic rock mechanics principles will be pointed out. The support system must function in concert with the deformations that are inherent in the selected mining system. Following the support selection, the mechanics for installing support must be developed. This is best done through a cooperative effort between mine engineers, mine operators, safety personnel, equipment sup- pliers, and government inspectors both state and federal. Accident statistics, near miss statistics, review of equipment used by others, geologic features, etc. will necessarily have to be studied. The goal of equipment development and selection should be to develop inherent safety by removing the miner from the hazard area or by providing absolute protection for the miner if he must work in close proximity to the potential fall of ground. The role of good productivity in reducing the numbers of men exposed to hazards is emphasized as a good safety measure ROCK MECHANICS PRINCIPLES A thorough understanding of the ground reaction curve surrounding openings to be created is essential in the

Jan 1, 1982

By T. H. Watkins

COAL is the basis upon which the activities of the industrial nations of the world rest today. In order that the coal industry may bee restored to a reasonably healthy condition, it is essential that both the operator and the miner should understand that they are directly concerned and that their selfish interests demand that they take an active, intelligent, self-sacrificing view of the entire situation and do their part in restoring and repairing the economic structure. Foreign credits, foreign debts, unstable exchanges, destroyed markets, and inability through lack of credit to carry on as before, all require our attention and cooperation. DEEP CONCERN AS TO FUTURE There is deep concern as to the future and a realiza-tion on the part of some of these leaders of industry that they will have to sacrifice their personal time, away from their desks and the details of business, in order to cooperate with other groups in studying the situation and endeavoring to find the best method of utilizing their knowledge in improving conditions and averting further disaster. It is most unfortunate for the country and for labor itself that the labor chiefs are blind to these necessities, and hostile to every effort to secure their cooperation in rebuilding prosperity.

Jan 2, 1922