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By H. W. Gillett

MAINTENANCE of membership by the technical so¬cieties and the activity of these societies in spite of the adverse business situation have been noteworthy. This forcibly brings home the fact that industry recognizes that sound technical guidance is well worth its cost. The numerous difficulties and losses due to defects of various kinds arising from gas-metal reactions are now generally recognized and interest in these problems is widespread. The forthcoming A. I. M. E. round-table discussion of gas-metal problems will do much to clarify the situation and will permit us to assay our present knowledge and to suggest the proper direction for profitable future research. "The Age Hardening of Metal" was the title of the annual I. M. D. lecture delivered by Dr. Paul D. Merica. A critical review of the known facts relating to age-hardening phenomena was first given, followed by the presentation of a theory correlating the detailed observations which have been made regarding the mechanism of the hardening.

Jan 1, 1933

By AIME AIME

PURSUANT to a recommendation made by the Section delegates at their conference at the Annual Meeting of the A.I.M.E. last February, the Directors, at their meeting on March 15, 1944, appointed a committee charged with the duty of investigating the present status of licensing and registration of engineers, and to make a report on the whole subject for the information of the mining fraternity. The committee consisted of E. W. Ellis, chairman, H. D. Keiser, Henry T. Mudd, J. J. Croston, and Simon Strauss. Messrs. Keiser and Strauss were unable to assist in the work of the committee, and Mr. Mudd was forced to resign in July, his place being taken by A. F. Greaves-Walker. Able assistance was given the committee by T. Keith Legare, executive secretary of the National Council of State Boards of Engineering Examiners, and by Ed. ward Larson, executive secretary of the National Society of Professional Engineers. The accompanying somewhat condensed version of the report of Mr. Ellis's committee, dated Oct. 15, 1944, is confined to facts rather than to recommendations. The "Model Law" to which reference is made was first drafted by repre¬sentatives of six national engineering societies in 1911. It has since been amended many times, the latest version dated June 1943 is recommended to the State Licensing Boards as a pattern for formulating or amending state laws. A copy of the "Model Law" in pamphlet form will be sent to any member on request from A.I.M.E. headquarters while the supply lasts. The report:

Jan 1, 1945

By H. Foster Bain

FROM time to time geologists and mining engineers, impressed by the heavy demands made on our mineral reserves' by modern industry, and particularly by the steadily mounting rate of production necessary to meet that demand, have issued warnings as to the danger of exhaustion. There can be no dispute as to the fact that mineral deposits are exhaustible. New mineral, is not created to replace that taken from the earth and when a crop of mineral is once harvested another cannot be grown in the same area. The evidence of exhaustion 'of particular oreshoots, deposits, or even of whole districts is familiar to all who have mined. If one were to judge solely from the abandoned mills and prospect holes he would rightly conclude that mining is but a short-lived industry. If one were, furthermore, to assemble the data as to known reserves of almost any of the commonly used minerals, and divide them by the annual tonnage mined, he would come to the same conclusion. If, again, one were to consider the most carefully made estimates of competent men seeking to measure the earth's reserves of minerals and plot against them a projection of the curve of past consumption, he would be justified in viewing the situation with alarm.

Jan 1, 1930

By J. B. Fletcher

The Miami mine first started operations in 1910. For convenience, the history of the orebody can be divided into the following categories (Fig. 1): 1) 1910 to 1925: 24.4 million tons of high grade ore, mined by top slicing, sublevel caving, etc. 2) 1926 to 1954: 102 million tons of low grade ore, mined by block caving.

Jan 1, 1961

By Norman F. Schulz

The technical excellence of separation achieved in a mineral concentration process, or any other process where two constituents of any kind are physically separated from each other, is expressed uniquely and quantitatively by the separation efficiency (E,): E. = (R - R,), where R is the percentage of the valuable constituent and R, the percentage of the waste appearing in the concentrate. The separation efficiency meets all the usual requirements of a true efficiency and is independent of the nature of the process used. It can be visualized as the percentage of the feed material that, in effect, actually undergoes complete separation while the rest of the feed is distributed randomly and unchanged into the two separation products. The problem of quantitatively assessing the results of a mineral concentration process recurs whenever one tries to decide which of two similar test results is more desirable. Although economic factors may greatly influence the eventual choice of process, they usually have very little to do with the technical excellence of a separation and are, therefore, not a consideration at this point. Concentrate grade and recovery, used simultaneously are the most widely accepted measures of performance, and if both the grade and the recovery are greater for one case than for another, the choice is simple. However, when the results of closely competitive operations are compared, it often occurs that one set of test results shows a higher grade and a lower recovery than another and the choice is no longer obvious. Laboratory investigations of a mineral concentration process applied to a given feed material can often be designed to yield successive paired values of concentrate grade and recovery over the practical range of the course of a separation process.' These results may be plotted as some combination of the cumulative values of grade, weight recovery, or unit recovery in the concentrate. The resulting correlations for two slightly different sets of conditions can then be compared qualitatively, or even quantitatively in particular cases.2 Such comparisons are not applicable, however, to individual concentration test results. The reduction of a separation test result to a single efficiency figure, preferably as a percentage of ideality, would afford the simplest and most precise means for comparing the results of competitive tests. The effective proportion of feed material that undergoes complete separation in any real concentration process, hereafter referred to as "separation efficiency," is such a figure. It is essily calculated from the usual feed and product data and can even be evaluated, in many cases, from data in publications describing various concentration processes. Mineral Concentration Processes and Their Evaluation Mineral Concentration Processes: The overall concentration process may be subdivided into a liberation process which severs the bonds between unlike mineral species, and a separation process, which sorts the resulting liberated particles into two products—a concentrate rich in mineral A and a tailing lean in mineral A. A perfect mineral concentration process is represented by the idealized scheme shown in Fig. 1 in which liberation and separation are not differentiated. The feed mixture consists of two mineral types which are completely liberated early in the process and then sorted by type. All the mineral particles of type A which respond uniquely to the selection forces acting in the ideal separator, report to the concentrate, while all the mineral particles of type non-A report to the tail-

Jan 1, 1971

By Russell B. Cornell, William B. Plank

AT the close of the academic year 1940-'41 the largest number of students ever recorded received their first or bachelor degree in the mineral technology schools of the United States. The total of men thus prepared to enter their professional careers in the mineral industries was 1601, a number nearly 12 per cent larger than two years ago and nearly 75 per cent larger than four years ago. Notwithstanding this increase in the number of graduates and as had been predicted in the preliminary report in February, there was a slight decrease in the total student population of the schools in both the United States and Canada. During the college year 1940-'41, 9133 students were enrolled in the 54 schools of the United States and 764 in six of the seven schools of Canada.

Jan 1, 1941

By CLAYTON C. BALL

In the year 1948, more than ever before, the coal industry established itself on the threshold of a new and exciting future expansion. While production did not equal the wartime and peacetime peaks of 1944 and 1947, it was, in review, a good coal year. During the latter part of the year a combination of mild weather, record stock piling, and general business slackening reduced coal demand to the extent that marginal mines suspended operations, while mines remaining active found it necessary to renew their attention to producing better products at lower operating costs.

Jan 1, 1949

By L. B. Davidson

The petroleum literature contains many reports on the relative permeability properties of porous media. However, only recently have studies of relative permeability at elevated temperatures been made.1 -5 Each of these studies presents relative permeability data on water-oil systems in linear sandpacks or sandstone cores under isothermal conditions. The results of these investigations are dissimilar. Edmondsonl found that in Berea sandstone a temperature-dependent effect was present, while Shilobod,2 using the same material, found no temperature dependence after normalizing for initial water saturation. Workers at Texas A&M U.3-5 found that the ratio kw/ko was temperature dependent in an unconsolidated system. The differences in results of these studies are probably a consequence of differences in the material employed, in the experimental procedures followed, and in the properties of the porous systems used. This paper describes an experimental investigation of permeability ratio temperature dependence, conducted to clarify some of the results obtained by previous workers. Each experiment described in this paper involved the isothermal displacement of Chevron No. 15 white oil by either nitrogen, steam, or distilled water and displacement of water by nitrogen. All permeability ratios were calculated using the Welge procedure. Values of the water-oil permeability ratio were obtained over the temperature range 75OF to 540°F. Results indicate the ratio is temperature dependent at low water saturations, probably due to interfacial effects. However, as the saturation is increased, temperature dependence decreases until, above some minimum saturation, the ratio becomes insensitive to temperature. Previously published work indicates that the dependence reappears at very high water saturations, a region of the ratio curve not completely examined in the present study. It appears that water-oil permeability ratios are temperature dependent at the extremes of the ratio curve where changes in interfacial tension with temperature induce variations in residual saturations. Between the extremes, there is a region in which the permeability ratio is insensitive to temperature. The size and location of this region is probably a function of the characteristics of the porous system. Gas-oil permeability ratios calculated from nitrogen-white oil displacement experiments indicate a definite temperature dependence over the range 75OF to 500°F and over the entire gas saturation range studied. Evidence discussed in this report indicates that this dependence is a consequence of molecular slippage in the gas phase. This is an extension of the Klinkenberg effect6 to two-phase systems at high temperatures (the existence of slippage in two-phase systems at room temperature has been demonstrated7). Evidence for a similar source of temperature dependence in superheated steam-white oil experiments

Jan 1, 1970

By Max Hebgen

Within the State of Montana the streams rise in the high mountains at. an elevation of from 5,000 to 8,000 ft. These streams leave the State line both east and west at elevations from 3,500 to 2,400 ft. It is, therefore, apparent. that all these streams have an average fall of 3,000 ft. within the confines of the. State, and many opportunities are presented on all streams. for the development of power, by taking advantage of the natural fall. It is probable that 1,000,000 h. p. can :be developed in the State of Montana. I. NATURAL FEATURES OF STATE AFFECTING POWER DEVELOPMENT. The main. range of the Rocky mountains, forming the Continental Divide, cuts the State of Montana into two parts. The eastern part is drained by the Missouri river and its tributaries, the Madison; Jefferson, Gallatin and Yellowstone, rivers. The western part is drained by tributaries to the Columbia river, the Clarks fork and the Kootenai river. The Clarks fork in turn is formed by the junction of Missoula and Flathead rivers, the latter, draining Flathead lake. The western part of the State. is mountainous and the eastern part is comparatively level. As a natural result the rivers in the western part are capable of generating large amounts of power, while in the eastern part of the State natural power sites are much fewer and farther apart. It also follows that in the mountainous districts large amounts of power are required for the mining industry, while in the eastern part of the State, which is principally devoted to agriculture, power is required in smaller quantities. ?

Jan 8, 1913

By AIME AIME

ALL technical men who are planning to visit the Century of Progress Exposition in Chicago this summer-and all reports indicate that it will be worth visiting-should try to be there during Engineers' Week, beginning June 26. At that time most of the national engineering societies of the country will hold important meetings in that city. Engineers will thus have an opportunity not only to see the Fair at a time when special programs have been arranged for their benefit, but will have the opportunity to meet their professional brothers and to attend technical sessions of direct interest to them. The A.I.M.E. headquarters will be at the Stevens Hotel, and it will be to the interest of every Institute member who expects to attend the Fair at that time to secure his accommodations as promptly as possible. A request to the Chairman of the Chicago Section, A.I.M.E., or to the Secretary's office in New York, will bring a copy of the program as soon as it is available, together with any in- formation desired about hotel accommodations or other matters. The Chairman of the Chicago Section is J. R. Van Pelt, and his address is Museum of Science and Industry, 1525 East 53rd St., Chicago.

Jan 1, 1933

By Elmer R. Kaiser

Industry Adopts Research: Seventy-Ave years ago Thomas A. Edison began in a modest way and with limited funds to gather about him men of various talents to form the first industrial research laboratory. His laboratory at Menlo Park, N. J., became famous for many discoveries and inventions, but possibly the most important of all may yet be the industrial research laboratory itself. Today, private industry operates 2500 research laboratories in which 135,000 persons' are directly and indirectly creating new processes and products and improving old ones, as well as developing new information to help keep the fountain of knowledge from running dry. In this change-making function, the scientific personnel comprises 41 pct; the technical personnel 26 pct; and the balance, 33 pct, nontechnical. The term "industrial research" has become so broad as to include almost everything beginning with the search for and discovery of the laws governing the properties of matter and energy to the development and testing of processes, methods, and equipment. These classes of investigation commonly merge so that no sharp boundary can be traced between them. The National Research Council therefore defines industrial research as "the endeavor to learn how to apply scientific facts to the service of mankind."' Currently, expenditures for research by industry are variously estimated at between $450,000,000 to $700,000,000 a year,' or about twice the expenditure for 1940. The President's Scientific Research Board" estimated that the national research and development for 1947 (excluding atomic energy) was as follows: A few companies spend as much as 5 pct of their gross receipts for research, but 1% to 2 pct is considered a good proportion by many." Shortages: Commendable as is the record of growth and accomplishment of science in industry, it is only a beginning. America and the rest of the world have merely sampled the fruits of industrial research; most industries have yet to make research the key to their future. A top research consultant, T. A. Boyd, of General Motors, states ". . . perhaps 90 per cent of all companies still have no research laboratories."Y or example, of more than 17,000 manufacturing concerns whose gross sales exceed $500,000 a year, less than 2500 have research laboratories. A still smaller proportion of the 184,230 manufacturing establishments in 161 industriese have or could afford their own research facilities. Yet, the small and mediurn-sized com,panies with less than 250 employees each, produce one half of the dollar volume of manufactured products.' How are these companies to participate in and share the benefits of research? Boyd gives two reasons for the inadequate number of laboratories in industry: Many people still do not appreciate the importance of research, nor understand its tremendous potentiali-

Jan 1, 1951

By Elmer R. Kaiser

Industry Adopts Research: Seventy-Ave years ago Thomas A. Edison began in a modest way and with limited funds to gather about him men of various talents to form the first industrial research laboratory. His laboratory at Menlo Park, N. J., became famous for many discoveries and inventions, but possibly the most important of all may yet be the industrial research laboratory itself. Today, private industry operates 2500 research laboratories in which 135,000 persons' are directly and indirectly creating new processes and products and improving old ones, as well as developing new information to help keep the fountain of knowledge from running dry. In this change-making function, the scientific personnel comprises 41 pct; the technical personnel 26 pct; and the balance, 33 pct, nontechnical. The term "industrial research" has become so broad as to include almost everything beginning with the search for and discovery of the laws governing the properties of matter and energy to the development and testing of processes, methods, and equipment. These classes of investigation commonly merge so that no sharp boundary can be traced between them. The National Research Council therefore defines industrial research as "the endeavor to learn how to apply scientific facts to the service of mankind."' Currently, expenditures for research by industry are variously estimated at between $450,000,000 to $700,000,000 a year,' or about twice the expenditure for 1940. The President's Scientific Research Board" estimated that the national research and development for 1947 (excluding atomic energy) was as follows: A few companies spend as much as 5 pct of their gross receipts for research, but 1% to 2 pct is considered a good proportion by many." Shortages: Commendable as is the record of growth and accomplishment of science in industry, it is only a beginning. America and the rest of the world have merely sampled the fruits of industrial research; most industries have yet to make research the key to their future. A top research consultant, T. A. Boyd, of General Motors, states ". . . perhaps 90 per cent of all companies still have no research laboratories."Y or example, of more than 17,000 manufacturing concerns whose gross sales exceed $500,000 a year, less than 2500 have research laboratories. A still smaller proportion of the 184,230 manufacturing establishments in 161 industriese have or could afford their own research facilities. Yet, the small and mediurn-sized com,panies with less than 250 employees each, produce one half of the dollar volume of manufactured products.' How are these companies to participate in and share the benefits of research? Boyd gives two reasons for the inadequate number of laboratories in industry: Many people still do not appreciate the importance of research, nor understand its tremendous potentiali-

Jan 1, 1951

By HOWARND N. EAVENSON

THE year 1930 resembled the preceding one in the coal industry in continuing the era of falling prices and 'of the abandonment of unprofitable mines. Practically all coal prices fell, and in the steam sizes during the last half of the year this was particularly true, due to the small industrial demand. No new mines of any size were opened in the bituminous coal industry, but there was a steady increase in the number of cleaning plants of all kinds built in all fields. It is estimated that at least nine million tons per year were added to the previous total of washed coal. The largest washing plant started during the year was that of the Buckeye Coal Co., at Nemacolin, Pa., with a capacity of 650 tons per hour. Fig. 1 shows - the mixing-bin, conveyor galleries, washing-plant and skip hoist, and Fig. 2 the 120-ft. Dorr thickener for collecting the 48-mesh material from the wash water. Dryers are used for drying the steam coal product. The following statement by J. R. Campbell shows the effect of cleaning on Pittsburgh coal in Greene County: "With the advent of the 650-t.p.h. efficient washing plant in Greene County at the Nemacolin mine of the Buckeye Coal Co., it has undoubtedly been demonstrated that the potential coking-metallurgical coals of the county can be brought within the pale of the highest grade high-volatile coals for steel manufacture. A few months' operation indicates that 9% per cent ash in the raw coal can be easily reduced to under 7 per cent ash in the washed coal and the sulfur from 1.60 per cent in the run of mine to 1.20 per cent sulfur in the washed coal.

Jan 1, 1931

By F. A. Forward, A. H. Ross, J. Halpern

Application of the carbonate leaching process to carno-tite ores has often been limited by the difficulty of obtaining simultaneous high recoveries of uranium and vanadium. The chemical aspects of this problem are discussed and the effect of prior roasting procedures on this discovery is described. IN treating carnotite ores by carbonate leaching it is often necessary to subject the ore to a prior roast. Among the advantages that may result from roasting are: 1) improvement in settling and filtering characteristics of the ore; 2) destruction of carbonaceous impurities that would otherwise contaminate the leach solution and consume carbonate reagent; and 3) substantial increase in extraction of vanadium, which is usually low when the un-roasted ore is leached. Recovery of vanadium may be an important factor in processing carnotite ores, and the fact that vanadium is usually recovered in good yield by acid leaching has often been an economic advantage over results obtained with carbonate leaching. It has been found that response of an ore to carbonate leaching, following roasting, depends primarily on its composition and on the conditions of the prior roast treatment, particularly with regard to the roasting temperature, the atmosphere maintained above the charge during roasting and cooling, and the presence of certain reagents. These factors, especially the last, virtually determine the extractions of uranium and vanadium attainable by carbonate leaching, as well as the reagent consumption on leaching, whereas adjustment of the leaching conditions has only a limited influence. These variables were examined systematically to elucidate roasting and carbonate leaching of carnotite ores and to establish a treatment yielding high recoveries of both uranium and vanadium. Tests were conducted on samples of four different Colorado Plateau ores, described in Table I. Roasting Procedure: The roasting tests were conducted in an electrically heated furnace in which the temperature was controlled to ±15°C. The ore (usually a 500-g charge) was ground to —100 mesh, mixed with the desired reagent, and spread in a silica tray to a bed depth of about 1/2 in. During the roast the charge was rabbled at intervals of 15 min. To provide free access of air the furnace was usually ventilated; however, in a few experiments a controlled atmosphere such as carbon dioxide or hydrogen was maintained above the charge. Leaching Procedure: The pulp, generally comprising 500 g of ore and a 2000-cc solution containing 80 g per liter of Na2CO8 and 20 g per liter of NaHCO3, was agitated in an autoclave at 120°C, under 30 psi 02. Samples were withdrawn periodically, and the solution and ore residue were analyzed. Under the conditions employed, maximum attainable extractions were generally achieved in 4

Jan 1, 1959

By J. W. Buch

IN THE FIELD of track haulage, interest has seemed to center on the question of larger mine cars both for handling material from loading point to shaft bottom or surface, and for shuttle service. Saving of time in car changing is obvious if larger cars are used. In addition, shorter trips result where car transportation is from face to opening without transfer. This also brings about side-track and equipment savings. Track shuttle service, using large automatic-dump cars (10 tons) between loading machines and trip loading point, has been a satisfactory solution for the operator who mechanizes a working mine regularly equipped with a large number of small mine cars. This development in track shuttle haulage, has made track installation and maintenance increasingly important, requiring closer supervision.

Jan 1, 1942

By Arthur S. Huey

AS the end of the collegiate year approaches, the problem of student employment again becomes acute. This subject divides itself into two phases: (1) employment prior to graduation and (2) employment following graduation. "Experience is the best teacher," according to the old adage, and the student needs all that he can get. He is afforded every opportunity to reap from his books the theories and principles of scientific and engineering practice, and occasionally he is privileged to make field trips to observe the practical side of the subject. But it is not enough for one to know the theory and to observe its application; it is also desirable for the student to get the feel of the tools during his training Such opportunities can only be afforded the student if the major companies cooperate with the universities in giving the student part-time and vacation work.

Jan 1, 1932

By E. M. Murphy

(Presented by invitation at a meeting of the Spokane Local Section of the Institute, Feb. 17, 1912.) EIGHT years ago the Hecla mine, a lead-silver producer, situated at Burke, Idaho, was producing ore from but two levels, the 300- and the 600-ft. All hoisting was done with a 12- by 16-in. slide-valve, double-reel, hoist. The hoist was being worked to its capacity and was unsuitable for hoisting from greater depths. As the work of opening a new level was about to be started, it became necessary to remodel the then-existing equipment or install a new hoist. The recent advent of electricity from Spokane had made available a cheaper power than steam. By a series of tests conducted throughout the Coeur d'Alène district, it was found that it cost $109 per year to generate a horse-power with steam. Electric power was to be had for $50 a horse-power per year. It was decided to substitute for the engines a motor-drive, of sufficient capacity to operate from the 900-ft. level, and ultimately install an entirely new hoist. After disconnecting the engines, installing a new shaft, and making a few minor changes, a 300-h-p., 2,300-volt, 514-rev. per min., variable-speed motor of the induction type was geared to the reel-shaft. The reels were supplied with 3/8 by 4-in. flat rope, and the duty of the hoist was about as follows: Cage, 1,700; ore, 2,600; car, 1,400; rope, 2,250; total, 7,950 pounds. The Bristol ammeter chart, Fig. 1, shows the combined current-consumption of the hoist- and mine-motors. The large intermittent load is clearly shown ; this produced harmful fluctuations in the voltage of the long, lightly-loaded, 60,000-volt transmission-line from Spokane to the Coeur d'Alènes. The power company received no compensation for the increased cost of producing power for this intermittent or fluctuating load. In order to protect its system from similar excessive

Sep 1, 1912

By Donald H. McLaughlin

ZEST in the search for new supplies of metallic ores and petroleum is difficult to maintain with stocks of raw materials accumulating and with over- production rightly or wrongly blamed for most of our industrial troubles. Enthusiasm over new methods of prospecting has consequently diminished and exploration programs in many fields have been drastically cur- tailed. Very naturally the effects have been felt with particular keeness in highly specialized phases of the work, such as geophysical prospecting, for the feverish scramble for new areas in which to drill beneath magnetic or electrical anomalies has abated, and there is even a lull in the firing in the battle over salt domes on the Gulf Coast. It is unquestionably an unhappy time for many of the organizations dependent on this work, but in certain respects the situation may be beneficial in correcting unsound practices that .have grown up through the necessity for haste and for quick decisions. With the restriction of the field to the more competent workers by the harsh rule of survival of the fittest, a general improvement, not only in technique but in business methods, can be expected which may go far in restoring public confidence. Geophysical prospecting in the short period that it has been utilized in North America, has suffered severely both from over-popularity and from excessive abuse. The former evil now

Jan 1, 1931

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Jan 1, 1938

By L. O. Howard

THERE are three active mines in the Chewelah-Colville district, the United Silver Copper near Chewelah, and the Old Dominion and the Chloride Queen near Colville. The Admiral near Valley is also doing development work. The Chewelah district is in the south central part of Stevens County in the Colville Valley. Chewelah, a thriving town of 1600 people, and the scene of operations of the Northwest Magnesite Co., is about the center of the district. It is situated in a farming community on the Spokane-Nelson branch of the Great Northern railway, about 65 miles north of Spokane. Only two or three of the mines in the district have been extensively developed, although many have been prospected. The general elevation of the valley, is about 1600 or 1700 ft., that of the mountain ranges on each side about 3000 to 4000 ft., with gentle slopes and rounded glaciated tops. Prospecting is often difficult because of much glacial debris.

Jan 1, 1925