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By Theodore Balberyszski

The gradual depletion of high-grade sulphide mineral deposits has turned the attention of the mineral industry to the recovery of metals from the oxides and silicates. Anionic (fatty acid) and cationic collectors have in some cases made flotation of non-sulphides possible, although in general, flotation of oxide ores is not as yet an economic process. Consequently, many attempts have been made to sulphidize the surface of the relevant oxide mineral and thus make it amenable to flotation. (1) (2) (3) In recent years, Bautista and Sollenberger(4) have investigated the conversion of a number of oxides to sulphides by reacting them with molten sulpur. This paper presents the results of investigations carried out at the School of Mineral and Metallurgical Engineering at the University of Minnesota to study the flotation characteristics of some sulphidized minerals. It is divided into two parts; Part I describes the sulphidization of a number of oxides and a silicate, and Part II presents the flotation behavior of the products of sulphidization.

Jan 1, 1968

By Thomas Niehoff

Many industrial processes require energy. Energy is required for melting or heating purposes. The heat can be generated by electrical heating or combustion/oxidation of hydrocarbons. Oxygen supports the combustion process. Oxygen is naturally contained in air with about 21 vol.-percent. The use of technical oxygen will allow an increase to the natural oxygen concentration of combustion air. Altering the combustion process by increasing the oxygen content has various effects. These effects are described and analyzed with regard to heat transfer, emissions and energy consumption. Industrial processes requiring oxyfuel are described and discussed regarding energy aspects.

Jan 1, 2008

By Andre Koekemoer, Gys Landman

At the moment, electronic initiation is migrating from a position of a specialist niche to that of a more widely applied technology. Ease of use and deployment rate are becoming aspects of greater concern for end users.

Jan 1, 2011

By Shailin Lalloo, Allan B. Nesbitt

A fluidised bed was exposed to high gravities by placing it in a centrifuge. The bed expansions were measured and compared with the bed expansions predicted by the Richardson-Zaki model (1954). The Richardson-Zaki model was found to predict effectively the fluidisation behaviour of defined particles in this increased gravity environment.

Jan 1, 2003

By Waldemar Lindgren

IN spite of a world production of lead amounting to 1,300,000 tons, of which the United States produces slightly less than one-half, it appears that the mines at present are hardly able to supply the demand. For this there are several reasons. The lead deposits, geologically speaking, were formed comparatively near the surface under conditions of lower temperatures, with the richer deposits often residuary; that is, enriched by surface water, and consequently soon exhausted. Lead is practically absent from a great part of the world. The great Canadian shield, the eastern part of the Dominion, contains practically none. Scandinavia contains no lead. It is absent from geo- logical formations of great age, but does occur in large quantities in the deposits in the Rocky Mountain region. These deposits are, more or less directly, of igneous origin, but here, too, there is a tendency of the lead shoots to concentrate in the upper part, and when they go down the deposits turn to zinc-copper and some other metals. This is one of the best established facts of economic geology. The deposits of the Mississippi Valley district, from Kansas-Oklahoma, to Canada, are in comparatively accessible limestone beds, at a depth seldom more than 500 ft. Therefore, the lead is easily mined but more easily exhausted.

Jan 1, 1926

By J. A. Retty

HOLLINGER CONSOLIDATED GOLD MINES LTD., through two subsidiary companies, has the exclusive right to prospect in two contiguous areas in central Labrador. This paper presents the results of the mineral exploration that has been conducted in these areas to date. One of the subsidiaries of Hollinger. the Labrador Mining and Exploration Co. Ltd., under an agreement with the Newfoundland Commission of Government, holds an area of approximately 20,000 sq.mi., which comprises the western portion of Newfoundland-Labrador and includes the upper basins of the Hamilton and Naskaupi Rivers. (The main area of the deposits so far discovered may be located on a map at about 67° west longitude and 55° north latitude.) The other subsidiary of Hollinger, Hollinger North Shore Exploration Co. Ltd., has licensed from the Province of Quebec an area of approximately 3900 sq.mi. lying directly north of the Newfoundland-controlled area at the headwaters of the George, Whale, and Swampy Bay Rivers. The M. A. Hanna Co., large iron-ore operators of the Lake Superior region, are participating in the project. With the exception of the years 1940 and 1941, field work has been conducted in the Newfoundland area since 1936, and in the Quebec area since 1939. Hollinger assumed the management in 1942. The field base is at Hollinger Lake, some 300 miles north of the tidewater base at Seven Islands, Quebec, which, in turn, is just west of the mouth of the Moisie River, on the Gulf of St. Lawrence. Air transportation is used exclusively to service the operation.

Jan 1, 1945

By H. M. Shepard

THE copper industry operated at high capacity throughout 1947, with no serious tie-ups in operation as was the case in 1946, when almost the entire industry was shut down by a four-month strike. Refined copper production in the United States averaged 94,250 tons for the first eleven months and deliveries to domestic consumers, including foreign copper for domestic consumption, averaged 114,000 tons per month. On April 29 the import duty of 4d per lb was suspended until March 31, 1949. Copper prices fluctuated considerably for a short time thereafter. Over the year the price of domestic electrolytic copper at refineries on the Atlantic seaboard advanced from 19.225¢ on Jan. 2 to 21.200d on Dec. 24.

Jan 1, 1948

By HAROLD A. KNIGHT

The Miami Copper Co., Arizona, is asking Congress to reimpose the import duty of two cents per pound on copper which, by law, has been suspended until June 30, 1950. C. Donald Dallas, chairman of Revere Copper and Brass, champion of a duty-free regime as regards the red metal, has been answering E. H. Westlake, Miami president, now that Mr. Westlake's statement to stock- holders has been salted away for posterity on wire recorders. Even prior to this action and at the instigation of two prominent consumers of pig lead, the House of Representatives has, in the confines of committee, not yet reported out, as of June 16, a bill to suspend the duty on lead for another year from expiration of the present law June 30, 1949. But apparently the bill was started too late. Thus the tariff issue becomes a Rip Van Winkle again after having slept for several years in the mountains of metals scarcity. During the wartime scarcity and the boom days that followed, most metal producers welcomed a considerable influx of foreign metal since it gave them a little surcease from constant teleibhone calls asking why that delivery of 300 tons of lead, 250 tons of zinc, and 1000 tons of copper had been delayed. These were the days when it was such an undisputed sellers' market that the sellers had even thrown away their certificates of ownership. Another development that brings home the tariff situation, small in it- self but perhaps indicating a trend, has been the announced closing of

Jan 1, 1949

By Carl M. Fellman

LABOR disputes caused considerable turbulence in the coal mining industry during 1946. As an outcome of these disputes, a definitely fundamental change in safety procedure was instituted: establishment of safety regultions for coal mines through the agency of agreements between the miners' union and the agency or agencies operating the coal mines. Although a temporary plan at present, the future will determine the. extent to which it may become permanent. Notwithstanding the turmoil in the industry extending through much of the year, the safety record for the first eleven months of 1946 was the best in the history of the industry for that period. The fatality rate for 1946 is lower than in any other year in the history of coal mining in the United States. This follows a pattern inasmuch as new low coal-mine fatality records were also made in 1945, 1944, and 1943. The five-year period 1942 to 1946 inclusive has a coal-mining fatality rate far lower than any other five-year period in the history of the industry. It is significant that this period exactly coincides with the operation of Federal coal mine inspection which got under way early in 1942.

Jan 1, 1947

By John D. Sullivan

ALUMINUM and magnesium plants in the United States underwent enormous wartime expansion which made many wonder if ghost plants would result when industry swung back to a peacetime basis. Production capacity of primary aluminum ingots was stepped up from 150,000 tons annually to about 1,150,000 tons; magnesium production increased from 2500 tons in 1936 to nearly 200,000 in 1943, with a production capacity of some 300,000 tons. Not only was primary metal production enlarged but also the capacity of prime fabrications such as castings, forgings, extrusions, and sheets was correspondingly increased. In mid-December it was estimated that production of primary aluminum ingots in the United States in 1946 will be about 410,000 tons while consumption will be about 500,000, close to half of the wartime consumption. The 1946 estimated consumption of secondary aluminum is 200,000 tons. The critical shortage of soda ash is hindering production of primary metal, and the outlook for an early relief of this shortage is dark.

Jan 1, 1947

By Markus Pötsch, Andreas Gaich

Optimization of surface blasting based on 3D models from drone imagery and a closed loop that starts with an automatic analysis of the geometry and the geological conditions and ends with an objective assessment of the blast result.

Feb 1, 2020

By H. P. Knudsen

In most open pit gold mines ore waste selection is based on estimates made from blasthole samples. These estimates frequently are biased. While it is true that high grades and "outliers" can induce a bias they may not be the only reason for the persistent bias seen at many mines. This paper focuses on a source of the conditional bias. In this paper it is shown that the poor blasthole sampling can cause a conditional bias in the estimates.

Jan 1, 1991

By Jewels Stover, Charles A. Luxford

Oklahoma City is undergoing a replacement program for an existing 66in (1.675m) water pipeline that conveys raw water from Atoka Reservoir to the City. This pipeline currently crosses the Canadian River on elevated piers and is subject to flood hazards. To replace the existing pipeline and mitigate flood damage concerns, two parallel microtunnels will be constructed below the river channel. Access is from construction shafts located near the midpoint of the tunnels; opposing drives are launched from each shaft. This geometry dictated shafts of significant depth – exceeding 120 ft. (37m). To accommodate the casing pipe segments and microtunneling machines, a minimum shaft diameter of approximately 34 ft. (10.4m) was required. Due to the difficult geologic setting, a reinforced secant pile compression ring is specified by contract in the top 70 ft. (21.3m) of these construction shafts to provide a very low permeability support system.

Sep 8, 2021

By Carle R. Hayward

(Wilkes-Barre Meeting, June, 1911.) THE growing importance of metallography has caused a corresponding interest in the improvement of apparatus for preparing specimens of metals and alloys for microscopic examination. The purpose of this paper is to describe an electric heating-furnace, a grinding-and-polishing machine, and a device for mounting specimens, which are used in the metallographical work at the Massachusetts Institute of Technology. These three pieces of apparatus were designed and made in the laboratory of the Institute, and. each possesses some original features which may be of interest. ELECTRIC HEATING-FURNACE., The accurate control of heat necessary for metallographic work is best obtained by the electric-resistance furnace. Unfortunately, however, even the platinum-wound furnaces deteriorate with use and ultimately burn out, while the cheaper resistance-materials are often short-lived. Since the resistance-coil must be replaced from time to time, it is of advantage to be able to make this change with as little trouble as possible, and this is an important feature in the furnace shown in Fig. 1. A is a cylindrical galvanized-iron can, with two handles, B. A porcelain tube, C, passes through the central hole in the cover of the can and rests upon the asbestos disk, D; the bottom of the tube is held in place by the asbestos ring, E. The space, F, around the tube is filled with powdered magnesia. G is an ordinary assay-crucible, with the cover inverted so as to present a smooth top for supporting a second porcelain tube, H. The latter is wound with ?Excello " resistance-tape, 0.014

Dec 1, 1911

By AIME AIME

NEW YORKERS look forward to the third week of February as the time of the year when they can count on seeing their friends-from far and near gathered in the city for the four-day annual session of the Institute.., Indeed, the metropolitan district is so large that in engineer who lives in New, Jersey and has his office on the lower end of Manhattan island may easily pass a whole year without seeing an acquaintance who lives in Westchester and has an office near Forty-second Street. If the Institute served no other function than to provide a place where friendship may be renewed, ideas exchanged, and new acquaintances made it would still be worth while. But when about 30 technical sessions at which about 160 papers are read and discussed are compressed into four days the annual meeting is also entitled to high rank as an intensive course of post-graduate instruction in the newest development in mining and metallurgical technology. Last, but not least, it is the occasion of a good time for one and all, even if they do get more than a little behind on sleep before the end of the fourth day. Nine o'clock is the time set on Monday morning for the beginning of registration, but a half-hour before that a number have always 'put in an appearance, and this is fortunate, because by 10 o'clock four sessions had begun, those on mining methods, geophysics, a round table on the valuation of coal, and the session of the Local Section delegates. Three committees of the A. S. T. M. were also in simultaneous session, so the meeting may be fairly said to have started "in high."

Jan 1, 1931

By Clinton H. Crane

DR. TILNEY, the great expert on the study of the development of the brain of human beings and animals, tells us that the greatest difference between the human brain and the brain of animals is that man alone has shown evidence of being able to predict the future. Just why he throws overboard the busy bee who lays up honey for the winter, the squirrel who gathers nuts, and the humble ant, I do not know. At any rate, it is nice to be assured by an authority that we have this power of prophecy. My own experience with attempting to prophesy the future has convinced me that our only possibility of being good prophets is to be good students of history.

Jan 1, 1940

By W. E. D. Stokes

The faster that aircraft fly the sooner some new and stronger material must be found to take the place of the present aluminum alloy used in all-metal planes. Experts of the National Advisory Committee for Aeronautics. in studying hi-speed aircraft, are convinced that the present all-metal plane, of semi-monocoque, aluminum alloy construction, is not the ultimate in aircraft design. Magnesium alloys and steel are under consideration.

Jan 1, 1942

By H. P. Greenwald

IN the year just passed the Coal Division's Committee on Rock-Dusting reviewed the status of this safety measure in American coal mines and prepared a paper thereon which will be presented at the February meeting of the Institute. This paper supplements one appearing in Vol. 139 of the "Transactions," page 87 (1940). Because that paper will be issued soon, only a summary is given herein.

Jan 1, 1944

By Oliver Bololes

UNDER the able leadership of Samuel H. Dolbear, the Committee on Nonmetallic Minerals furnished a program of sixteen papers comprising three sessions. An outstanding accomplishment in technology presented at the first session by Benjamin L. Miller and C. H. Breerwood is the application of flotation to the purification of limestone used in cement manufacture. In place of selective quarrying to provide high-grade raw material, the quarry-run stone is pulverized and treated in froth flotation cells for removal of free silica and mica. Some advantages are cheaper quarrying, more complete utilization of quarry rock, avoidance of purchasing high calcium stone, lower fuel cost and improvement in the finished cement. Paul M. Tyler presented the general subject of milling methods as applied to nonmetal lies. He pointed out the importance of some of the more recent refinements in ore dressing, and urged the need of a wider appreciation of their possibilities. The gypsum industry of Canada was described by L. H. Cole. Crystal growth during the setting process was illustrated by moving pictures. The Coastal Plain and interior salt

Jan 1, 1935

By AIME AIME

THE Iron and Steel and Institute of Metals Divisions will meet jointly at the Statler Hotel, Detroit, Oct. 4 and 5, during the Metal Congress, Oct. 2-6. The Wire Association, the American Welding Society and the American Society for Steel Treating, together with the two Divisions of the Institute, constitute the Congress this year, and each body offers an interesting technical program. The National Metal Exposition will, as usual, be held concurrently. Visiting metallurgists will find themselves engaged in a bit of research not listed in the program-a time study of how best to exploit in a few days both the Congress and all that the place of meeting has to offer. For Detroit, the beautiful "City of the Straits," is third in rank industrially in the United States, and its great manufacturing plants offer much of metallurgical interest. This is especially true of the automobile plants which will be open to members of the various societies during the week of the Congress.

Jan 1, 1933