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By H. Evans, L. A. Hunt

In the pellet-producing industry it is sometimes claimed that "The pellets are made in the concentrator," or that "The key to good pellets is in the balling operation." However, one claim is generally agreed on: If you can put in, on, and through the indurating furnace a good green ball of Proper size and adequate strength to withstand the handling, load, dehydration, and thermal shock until it is properly heat-hardened, you will have the pellet product you desire-that is, a "competent" green ball. The strength requirements that enable a competent green ball to withstand the environment of the indurating furnace are usually less restrictive than those for transporting the green ball from its source of production to the furnace. Experience has shown that different types of material may have different balling characteristics which may impose limitations on the quality of the green ball that can easily be produced under normal conditions. Therefore, if a specific material will produce a green ball that meets the physical requirements for competency in the furnace, but not for handling or transportation, various practices must be instituted to overcome this deficiency. In other words, if a normal handling system is too rigorous for the green balls that can be produced under standard conditions, then "handling with care" should be tried.

Jan 5, 1967

By R. D. Parker

LARGEST of any hoist installation ever manufactured in Canada is that being erected at No. 5 shaft, Creighton mine, of the Inter- national Nickel Company of Canada, Limited. It is a bicylindrical conical- drum hoist with the drums arranged in tandem, and driven by two direct- current motors through single reduction gearing. This hoist was designed by the Canadian Allis-Chalmers, Limited and manufactured at their works in Lachine, Quebec.

Jan 1, 1936

By G. D. TRANT

HOT metal is commonly transported from the blast furnace to the open hearth by one or the other of two general methods: (1) by hot-metal ladles, usually in conjunction with a stationary mixer, or; (2) by means of mixer-type ladle cars, taking the place of both the hot-metal ladles and the stationary mixer. In both cases, the use of transfer ladles for charging the metal into the open-hearth furnaces is necessary. The American Rolling Mill Co. at its Middletown division, adopted hot metal practice on. June 2, 1928. The pig iron is produced' in a .blast furnace about 11 miles from the open-hearth furnaces, and is trans- ported in Pugh-type mixer cars having a capacity of 150 gross tons each. Three cars are in service and handle the delivery of hot metal to the pig machine and the open-hearth furnaces. The capacity of the blast furnace is 550 tons and casts are made every four hours.

Jan 1, 1929

By Charles Catlett

Having had charge during the past year of the operations of the New River Coke Company, the second largest, if not the largest, coke-producer in this district, my attention was called particularly to the yield of coke from the coal as coked in a bank of beehive ovens, as the record showed that this yield, while believed to be well up with the practice of the district, was much lower than the analysis of the coal indicated it should be. The coal is well known to many members of the Institute, and the scope of this paper does not include a discussion of its occurrence and development. It suffices to say that the New River district comprises the mines working on the coals of No. XII. or the Conglomerate Series of the Rogers brothers, which are located on New river and its tributaries, and which find an outlet for their product east and west over the Chesapeake and Ohio Railway. The New river through this section carries the drainage from an extensive peneplain in which it has formed a very striking and stupendous canon, probably the most striking east of the Mississippi river. The only practical access to this territory is by means of this canon and the Chesapeake and Ohio road, and the opportunities for development by other lines may be considered as nil. If it were not for the fact that this road, farther west, reaches and develops entirely different coals, which are found in other measures, the New River district might properly be spoken of (as is now done at times) as the " C and 0. field." For fuller information on the geology of the region, those interested are referred to the ery complete monograph on the subject by Mendenhall and Campbell of the United States Geological Survey. The rocks are the same as those which carry the more widely

Jan 1, 1900

Jan 1, 1894

By P. Barnes

Exact accounts hare been kept of the cost of these chimneys, and it may he a matter of some possible interest. that the plans and details of cost should be laid before the Institute. The statement of cost herewith submitted does not give minute particulars of the weights or quantities of material used, although these are noted upon the company's books.

By A. P. Young, L. I. Marsh

HE relationship between microstructure and *- fracture is of interest in many metals and alloys. This relationship is sometimes established by examining the fracture surfaces and the flat surfaces near the fracture path in tensile samples. However, it is often difficult to tell from examining the fractured sample whether the fracture is intergranular, intra-granular, or a mixture of both. Also, it is often of interest to follow the progress of slip, twinning, or crack formation along the fracture path before fracture occurs. The ambiguity concerning the type of fracture generally can be resolved if the area along the path of ultimate fracture can be photographed at inter-

Jan 1, 1959

By AIME AIME

MANY of the important papers to be presented at the World Congress of Engineering at Tokyo, in November, 1929, are being furnished by members of A.I.M.E. and a list of them is given below: "Fifty Years of Physical Metallurgy,,-by H. M. Boylston, Case School of Applied Science, Cleveland, Ohio.

Jan 1, 1929

By Irving Hartmann, H. P. Greenwald

READERS of this journal are familiar with the danger of coal-dust explosions in mines and with recommended means for preventing them. The subject was treated in a paper by R. R. Sayers in the January 1943 issue, as well as in several previous articles. Similarly the danger of dust explosions is generally recognized in the handling of grain dust, flour, starch, sugar, and other carbonaceous products. However, until recently, few people realized that an analogous, real explosion hazard exists wherever dust suspensions of certain finely divided metal powders are formed. This lack of knowledge was in part due to the fact that until a few years ago only a small number of metal powders, such as aluminum, magnesium, zinc, iron, and tungsten, were produced, in comparatively small volume, and partly because information on the explosibility of metal powders was lacking.

Jan 1, 1945

By Zárate G. E.

Practical and statistical considerations concerned with the sampling, sample preparation and chemical analysis of precious metal ores are reviewed. The principal requirements related with the characteristics of sample cutter, sample preparation, equipment and methods are discussed. The main errors introduced in the different stages of the sampling systems are defined. The application of statistical techniques to evaluate these errors to determine the ore grade variation and to design the number of increments needed to get an accurate assay are presented. Finally, results obtained with the application of this method to gold and silver ores are analyzed and some recommendations are given.

Jan 1, 1984

By Albert Sauveur

Jan 1, 1924

By Albert Sauveur

Jan 1, 1924

By Hannon, J. W. G.

Silicosis is today's most important industrial disease and probably dates back to the Stone Age. Since the industrial revolution, increasing attention has been paid to those occupations where mineral dust is present in the air breathed by the workers. For many years it was assumed that the inhalation of all mineral dusts was hazardous. but investigations conducted in several countries pointed the statistical finger of guilt at free silica in any of its numerous physical forms as a dust of outstanding toxicity. Recognition of silica as the chief hazard has resulted in widespread use of the term "silicosis." Depending upon the concentration of finely divided silica dust to which the individual is exposed and the duration of exposure, silicosis may become a disabling condition in from one to thirty years. The structure of the lung and respiratory passages is such that only minute particles of silica can gain entry to the air cells in the lung (5 microns or under are most toxic). When these minute particles gain entry to the lung tissues they stimulate certain protective cells in the lung to multiply at an excessive rate. The cell's undergo inflammatory changes which result in nodular scars and a low-grade inflammation of the lung tissue. These progressive changes in the lung structure gradually encroach

Jan 1, 1949

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 E. L. Jr. Spain

THE deposits described in this paper occur over much of Wayne County and in the southeast portion of Hardin County, Tennessee, and in the northeast and northwest portions of Mississippi and Alabama respec-tively. The presence of tripoli in this region has been known for some time and descriptions of various occurrences in Tennessee have been made by Jewell1 and Miser2, while Hilgard3, Lowe4 and Logan5 have treated the deposits that occur in the adjacent portions of Alabama and Mississippi, but there has not been a general survey of the entire field summarizing completely the geology of the deposits with respect to their origin and stratigraphic relationships. During 1934, while engaged in surveys of mineral resources through this region for the Tennessee Valley Authority, the writer collected data with this in mind, and has assembled them in this report. He is indebted to H. S. Rankin and N. A. Rose, of the Tennessee Valley Authority Geology Division, for field assistance.

Jan 1, 1936

By Arthur Mitchell

POSSIBLY in no other of the non-ferrous mining districts of this country has the use and develop-ment of mechanical loaders been carried to such an extent as in the "lead belt" of Southeast Missouri. It has become apparent to the four mining companies in the district that it is imperative to apply satisfactory mechanical methods to the chief remaining stage of the entire operations-mining, milling, smelting and refining-in which manual labor is still largely used to handle material in process. With increasing wages and with the reduction of the metal divisor by the extension of mining into lower-grade orebodies, the shoveling cost per ton of lead produced has become relatively so large that in an effort to reduce it there is ample justification for considerable capital expenditure. Hand shovelers load about 18 tons of ore per shift and the average grade is less than five per cent. lead. Further, the ore is relatively heavy, about 21 cu. ft. to the ton when broken, and is often so coarse and so closely compacted after shooting that it requires much more block-holing, sledging, and muscular effort to shovel than, for example, does the cherty and more granular ore of the Joplin district or the finer ore in the headings of a drift mine. No mining company desires to pay for mere back muscles if it be economically feasible to avoid it, and labor saving machinery should be susceptible of operation by older employees, who are no longer capable of the more strenuous manual occupations.

Jan 4, 1923

By T. L. Johnston

MUCH has been said and written about deep mine shafts and deep drill holes as man in his search for mineral wealth digs deeper into the earth's crust. Each year some new extra depth is heralded as a record, but with unlimited possibilities of going still deeper. In contrast to "digging deep," "mining high" is limited by the height of the mountains (Mt. Everest being the maximum with its 29,000-ft. elevation) and also by the extent of human endurance. An ex- ample of what might be called near- stratosphere mining in what is probably the highest mine worked by compressed air in the world is seen in a recent project in the Andes mountains of southwestern Bolivia.

Jan 1, 1939

By Mark C. Malamphy

AT present the Federal Government represents the only organization applying geophysical methods of prospecting in Brazil. The geophysical work of the National Department of Mineral Production, which will be described in the following pages, must be considered as a program of experimental work designed to demonstrate the applicability of the more or less "standard" methods of geophysical prospecting to various problems of economic interest in Brazil by means of practical examples of results obtained in certain typical areas. Our work is somewhat similar to that of the Imperial Geophysical Experimental Survey of Australia, but our task has been greatly simplified by the ever increasing number of technical publications relative to the theory of instruments and methods.

Jan 1, 1936

By CARLE R. HAYWARDC

BEFORE discussing this subject it is necessary to define somewhat the meaning of the tern metallurgical.. When I was a student at M. I. T. ore-dressing was not thought of as metallurgy in any sense of the word, but it was considered as more closely allied to mining, enabling the miner to market an otherwise unmarketable product, or at least to market it to better advantage. Progress in ore-dressing has gradually allied it more closely with smelting, for at present the raw material received by the smelter is predominantly concentrates and smelting practice has been profoundly affected by the products of the concentrating mill. It is not surprising therefore that in many schools ore-dressing is frankly considered as metallurgy and although there may be some dissenting opinions it will be considered as such in this discussion. Twenty-five years ago at M. I. T. metallography was taught in a few optional lectures. This subject has developed rapidly and been expanded into the new and increasingly important field of physical metallurgy. To many metallurgists the -term metallurgy means only physical metallurgy. They know little or nothing about smelting and leaching and even less about ore-dressing. Having then broadened the scope of the term metal¬lurgy to cover ore-dressing, smelting, leaching and phys-

Jan 1, 1930

By AIME AIME

MOST of the copper mines in Canada are favored by nature in having other metals besides, copper in their ore, which puts them in a most satisfactory competitive position. Noranda ore has an important gold content, Flin Flon gold and zinc, and International Nickel of course has nickel. All of the larger copper companies in Canada operated during 1.933 and the total production of copper exceeded that of the year before. The Britannia Mining and Smelting Co. worked out to succcessful conclusion a three-product flotation process for separating the copper, zinc and iron from its low-grade ore. Although the method and equipment is different from that used at the Flin Flon mine, the object is the same, that

Jan 1, 1934