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By A. A. Burr, D. G. Ebeling

The effects of casting texture, grain orientation and grain size upon the performance of Alnico permanent magnets is described. Single-crystal specimens were produced by special sintering and grain coarsening techniques to study the effect of crystal orientation. In addition to texture and orientation effects, an analysis of the results indicates that the permanent magnet performance is impaired by a refinement of the grain size. AN excellent historical review of the development of Alnico permanent magnets has been prepared by Bozorth.1 The desirable permanent magnet characteristics of Fe-Ni-A1 alloys were discovered in 1932 by Mishima.2,3 The work of Ruder' showed that the alloys were age-hardenable, and Betteridge5 defined the best composition and heat treatment for the magnetically isotropic alloy known as "Alnico 3." Horsburgh and Tetley0 increased the energy product by the addition of cobalt and copper, "Alnico 2," and Oliver and Sheddon7 demonstrated that cooling in a magnetic field improved the residual induction of this alloy. Jonas8,9 then disclosed the great practical benefits of heat treating an alloy of higher cobalt content in a magnetic field and the resulting alloy, "Alnico 5," has become the standard of the industry. This paper describes the fundamental aspects of a procedure which can be used to further improve the properties of these anisotropic permanent magnet alloys. A study of the casting techniques used in the production of anisotropic Alnico permanent magnets indicated that the magnetic quality was affected by the as-cast macrostructure. Improved performance was observed in magnets containing a high percentage of columnar grains whose long axes were parallel to the magnetic axis of the casting. McCaig10 studied the effect of such columnar grain structures upon the magnetostriction characteristics of similar alloys, however no data was presented showing the effects on other magnetic properties. The following paragraphs describe two experiments which were conducted to determine the effect of various grain orientations upon the energy product. Special composite molds were prepared of highly conductive and highly refractive components to remove the heat of solidification from the casting in a controlled manner. Representative macrostructures produced by these techniques are shown in Fig. 1, along with the relative volumes of favorably oriented columnar grains. The alloy, Alnico 5, has the highest permanent magnet performance of any commercial magnet material. It has the nominal weight composition of 8 pct Al, 14 pct Ni, 24 pct Co, 3 pct Cu, and 51 pct Fe. A heat of this material was cast into molds producing the type A and B grain structures shown in Fig. 1 and pairs of the resulting magnets were placed in heat-treating boats so as to eliminate any biasing effects of boat position. After a standard heat treatment the type A magnets, with 16 pct of the volume composed of favorably aligned grains, had a maximum energy value of 3,940,000 gauss-oersteds, while the type B magnets with 73 pct aligned grains averaged 5,090,000. This large im-

Jan 1, 1954

By P. G. Shewmon

If interfacial equilibrium is maintained at the interface between a growing precipitate and the supersaturated matrix, so that solute diffusion alone determines the growth rate, the precipitate shape should evolve toward that characteristic of the dendrites found in solidification. However, this shape is rarely observed in precipitation reactions proceeding at high temperatures where interfacial equilibrium is usually felt to prevail. Thus some other stabilizing factor must enter, to keep the interface smooth. It is shown that a slow interfacial reaction (low interfacial mobility) will stabilize the interface, while transformation stresses have a IN studying the kinetics of phase transformations such as solidification or proeutectoid precipitation at high temperatures, it is customary to assume that equilibrium exists across the interface and that the rate of the reaction is determined by the rate at which heat and solute diffuse to and from the interface. In the case of precipitation, such an assumption predicts an almost infinite rate of initial growth. It is generally stated that the rate cannot be infinite and that during some initial period the rate must be determined not by solute diffusion but by an interfacial reaction, i.e., transferring atoms across the interface. The duration of this much weaker stabilizing eFfect and impurities tend to enhance instability. It is also concluded that a sets an upper limit on the wavelength of the perturbation that can give instability. Thus initially all flat or smoothly curved particle interfaces will be stable even if their growth is diffusion-controlled. Proeutectoid precipitation in the Fe-C system is considered in some detail and it is shown that the experimental results can only be rationalized if the growth rate of ferrite in steel transformations is determined by a slow interfacial reaction for all hut a few orientations between the two phases. initial period has never been clearly established, but it is generally assumed to be too short to affect any measurable results.' Several authors have pointed out that in the case of interfacial equilibrium any bump in the surface will grow out ahead of the planar interface due to the higher gradient in front of it.2j3 Thus the interface will be unstable with respect to an irregular interface with points (plates) propagating rapidly out ahead of the interface into the supersaturated phase. Recently, Mullins and Sekerka have given equations for the stabilizing effect of surface tenion.~ They found that for particles with a radius of curvature of 1 p or greater the stabilizing effect of surface tension will be completely overcome by a supercooling, or supersaturation, of as little as

Jan 1, 1965

By William J., Coulter

IN the early days of Colorado mining, between 1880 and 1900, when Leadville, Kokomo, and Robinson were boom mining camps, the entire area around Climax for a matter of fifteen miles was overrun with prospectors, so the mineralized outcrop at Climax was not unknown. The principal interest in minerals during this period was in gold, silver, and lead, and since the Climax outcrop showed none of these it drew little attention. Geology played an important part in bringing prospectors to the very edge of the Climax deposit. The Mosquito fault, which crosses near the base of Bartlett Mountain, continues as an important geological structure, at least as far as Leadville some twelve miles distant, and at the base of Bartlett Mountain the vertical throw on the fault is estimated to be between 2000 and 5000 ft. The sedimentary beds known to the Leadville district are all present on Bartlett Mountain to the north of the Mosquito fault, which cuts them off abruptly, and exposes the Pre-Cambrian rocks that underlaid them, so the prospectors, who were searching for gold, silver, and lead in the sediments

Jan 1, 1946

By James Lorimer

THE topography at the Stan Trg mine facilitated early exploration by adits; in consequence adit levels were developed at horizons 865, 795, and 760 meters above sea level, and the levels in the mine 'are named according to their elevation. Exploitation started from the 760-m. level . upwards while simultaneously first steps were taken with regard to mining in depth. A deep dewatering adit 2.5 km. long now gives access to the deposit at the 610-m. horizon which also is connected with the 760-m. adit level by a three-compartment main hoisting shaft. Main levels have been developed internally from

Jan 1, 1936

By A. E. Chute

The shortage of sulfur is not only continuing but appears to be worsening, attended by steadily rising prices. At the same time emphasis on air-pollution abatement is also increasing. These two factors, a rising market and the growth of environmental attention, have encouraged producers to carefully review all possible sulfur sources. As a result, production of sulfur from hydrogen sulfide occurring in petroleum is receiving greater attention than ever before. Until about a decade ago, the practice of recovering sulfur from hydrogen sulfide separated from gases (either found naturally or generated in desulfurization of liquid petroleum) was wide1y recognized but contributed little to total free-world sulfur production. However, during the past ten years, the production of sulfur from this source has increased so rapidly that it now accounts for a substantial portion of total production. This trend shows no signs of slackening, and current forecasts predict that recovered sulfur may become the dominant source of supply within ten years, exceeding mined sulfur production. This paper is intended to list sulfur sources and relationships, and to discuss the potential of producing sulfur from petroleum. The processing involved, in addition to product storage and transportation will also be discussed along with important economic aspects of sulfur recovered from hydrogen sulfide. For many years, most of the world's elemental sulfur has been produced from salt domes, predominantly by the Frasch process. During the past decade, however, another production source has developed so quickly that it is expected to surpass the Frasch production sources within a short time. This new source lies in the petroleum gases and liquids from which dramatically increasing quantities of elemental sulfur are being recovered. In the phraseology of the trade, the sulfur so obtained is know as "recovered sulfur," a term which does not, as one might expect, include sulfur recovered from other sources such as smelter gases. The growth rate of recovered sulfur compared to that of Frasch sulfur, total elemental sulfur, and total Free World sulfur in all forms is shown in Fig. 1 Since 1963, sulfur consumption has exceeded production,with the natural result that the price of sulfurhas continually increased. The posted price reported for f.o.b. Port Sulphur, La., has risen from as low as $18 per ton in 1962 to $32.50 per ton in mid-1967. With freight and other charges, delivered prices have of course run much higher, amounting to $45 or $46 per ton on the east and west coasts. In some cases, spot sales for as much as $60 have been reported. Although it is playing an ever-increasing role in the sulfur market, recovered sulfur was originally a by-product of the removal of hydrogen sulfide from natural and petroleum refinery gases. Today, however, it is often the most valuable product of a multi-product processing facility. Since there are two major sources of recovered sulfur—production and refining processes —natural gas is included with liquid petroleum for purposes of this discussion. Sulfur from these sources is produced in the form of gaseous hydrogen sulfide which is removed from a gas stream and converted to elemental sulfur. Gases in which hydrogen sulfide occurs naturally are natural gas and the gas produced from a high=pres-sure crude=oil or condensate field.

Jan 1, 1969

By Richard P. Rothwell

IN the pear 1881, I visited San Domingo, in the interest of French capitalists, to examine and report upon certain "concessions" of gold-bearing gravel and quartz veins, on the Isabella and Jaina rivers and their tributaries. This district is periodically reported to he extraordinarily rich, and there is oast around it the glamour of the mysterious shipments of gold, credited, in romance and in more or less romantic history, to Columbus and the Spaniards of the fifteenth and sixteenth centuries. Since considerable sums of money and several valuable lives have been lost in the unsuccessful search for its profitable mines, it seems desirable to place on record Borne of the information collected concerning the value of these famous gold fields, with the hope of facilitating the work of those who may hereafter be called on to investigate these claims, and of preventing the unnecessary waste of capital. It is needless to add that the capitalists for whom my investigations were made abandoned the enterprise they had in view,although no doubt similar schemes will be brought forward many times in the future, as they have been in the past, under the fervent advocacy of too sanguine enthusiasts. Since the time of the Spanish occupation of the Island of San Domingo, in 1497, when Columbus Found the natives wearing ornaments of gold, more or less of the precious metal has been obtained annually by washing the gold-bearing sands of several of its streams. It is said that during the Spanish domination, when the native Indians were held in the most abject servitude, a certain amount of gold was required of each one as the rault of his labor. Uuder this

Jan 1, 1882

By AIME AIME

T HE Board of Directors of the A. I. M. E. held a meeting at Institute headquarters on Jan. 28, 1921. There were present 10 directors and 14 guests, the secretary and the assistant secretary. The following actions of the Executive and Finance Committees were approved: Wilkes-Barre Meeting, Sept. 12 to 17, 1921; authorization of Oregon Section; authorization of Upper Peninsula Section; appointment of Philip W. Henry and Thomas H. Leggett on special committee on Code of Ethics; and presentation of five copies of Raymond Memorial Volume to T. A. Rickard, who edited it. The By-Laws of the Ohio Section were approved. The resolutions in reference to the payment of certain contributions and assessments to the Library Board of the United Engineering Societies, adopted by the Board of Directors on June 27, 1919, were rescinded, and the resolution adopted that the income of the James Douglas Trust of $100,000 be paid over to the Library or otherwise applied by it for the purpose of maintaining the Scientific Library of this Institute in such manner as may be deemed advisable in furtherance of the purposes of such trust, and that said income shall be paid on account of and included in. the assessment levied by the United Engineering Societies on the Institute for the maintenance of the joint libraries of the Founder Societies.

Jan 1, 1921

By H. NORTON JOHNSON

THE oil industry in California during 1929 reached new heights and new depths in the discovery and development of the oil resources of the State. The discovery of new fields, and more especially the discovery and development of deeper prolific sands in known fields has, for the first time in its history, brought the potential production of completed wells within the State to over 1,000,000 bbl. oil per day. Constant improvement in equipment and technique has made possible economic development to depths unheard of but a few short years ago. Commercial production from a depth of over 4000 ft. was considered quite an accomplishment in 1923 when the Meyer sand at Santa Fe Springs was developed, and when later oil was successfully raised from this depth.

Jan 1, 1930

South Dakota State Geological and Natural History Survey, State University, Vermillion, S D. A list of publications will be sent upon request Many of the publications are out of print A series of Biennial Reports of the State Geologist will be sent upon receipt of three cents for postage on each, and are available as follows: 1918-20, 1920-22, 1922-24, 1924-26, 1926-28, 1928-30 Available Bulletins of greatest interest are: Bulletin 4, Pre¬liminary report of the geology of the Rosebud Reservation (1909), 10 cents; 10, Possibilities of oil in South Dakota (1922), 10 cents A series of Circulars (5 cents each) deals with the possibilities of oil and gas in various parts of the state, as follows¬ Circular 8, Eastern Pennington County (1921), 9, Western Dewey County (1922); 10, Northern Dewey County (1922), 12, Eastern Harding County (1923), 13, Northern Ziebach County (1923); 20, Western Ziebach County (1925), 23, Northeastern Meade County (1925); 27, Western Corson County Other Circulars (5 cents each) are: Circular 16, The natural resources of South Dakota (1924), 22, Structures ,in northern Haakon County (1925); 24, The Ragged Butte structure (1925), 25, The structure of western South Dakota (1925), 28, Structures in western Haakon and eastern Pennington counties (1926)

Jan 1, 1933

By M. T. Halbouty

The Laredo oil district, South Texas, includes an area of approximately 200 miles long north and south and 75 miles wide, embracing the following counties: Starr, Zapata, Jim Hogg, Webb, Duval and McMullen. The area is relatively old in respect to the production of oil, as the first oil was discovered and produced in the Piedra Pintas field in Duval County on Sept. 10, 1905. Since that date, continuous new discoveries have contributed to the development of this district until, at the present time, it is one of the important oil-producing and gas-producing areas in the world. The year 1937 also had its share of new discoveries in the district, including not only new oil fields but also new sands in already producing pools and important extensions to existing sands and fields. Among the most important field discoveries, by counties, are: Duval County..... Benavides, Sweden, Thomas-Lockhart, Labbe and Lundell fields Jim Hogg County.. Las Animas field McMullen County. Ezzell field Starr County...... El Tanque field Webb County..... Killam and Oilton fields Of these, Benavides, Oilton, Killam and Ezzell have so far proved themselves most important; the Benavides field, Duval County, showing by far the most activity. For the year 1937, therc were 283 wildcat tests drilled in this district, of which 35 were oil producers, 20 completed as gas wells and 228 abandoned as dry holes. Duval County, as usual, received the greatest amount of wildcat drilling, having 21 oil wells, 5 gas wells and 63 dry holes completed during the year for a total of 89 tests. Next came Webb County with 4 oil wells, 4 gas wells and 53 dry holes for a total of 61 tests.The Laredo oil district, South Texas, includes an area of approximately 200 miles long north and south and 75 miles wide, embracing the following counties: Starr, Zapata, Jim Hogg, Webb, Duval and McMullen. The area is relatively old in respect to the production of oil, as the first oil was discovered and produced in the Piedra Pintas field in Duval County on Sept. 10, 1905. Since that date, continuous new discoveries have contributed to the development of this district until, at the present time, it is one of the important oil-producing and gas-producing areas in the world. The year 1937 also had its share of new discoveries in the district, including not only new oil fields but also new sands in already producing pools and important extensions to existing sands and fields. Among the most important field discoveries, by counties, are: Duval County..... Benavides, Sweden, Thomas-Lockhart, Labbe and Lundell fields Jim Hogg County.. Las Animas field McMullen County. Ezzell field Starr County...... El Tanque field Webb County..... Killam and Oilton fields Of these, Benavides, Oilton, Killam and Ezzell have so far proved themselves most important; the Benavides field, Duval County, showing by far the most activity. For the year 1937, therc were 283 wildcat tests drilled in this district, of which 35 were oil producers, 20 completed as gas wells and 228 abandoned as dry holes. Duval County, as usual, received the greatest amount of wildcat drilling, having 21 oil wells, 5 gas wells and 63 dry holes completed during the year for a total of 89 tests. Next came Webb County with 4 oil wells, 4 gas wells and 53 dry holes for a total of 61 tests.

Jan 1, 1938

By George Stone

THE stack gases from regenerative furnaces are very seldom utilized for the production of steam. If the temperature of the gases is not higher than 300° C. (572° F.) there is no economy in their use for this purpose, as the amount of available heat is very small and the temperature is so little above that of the steam that the interchange is too slow. With higher temperatures of the waste gases, however, good results can be obtained. At the plant of the New Jersey Zinc Co. (of Pa.) at Palmerton there are a number of return tubular boilers, each 6 ft. in diameter and 20 ft. long, with 96 3.5-in. tubes, which are heated by the waste gases from the spelter furnaces. These furnaces have continuous regenerators heating the air only and the stack gases reach the boilers at a temperature of about 450°. The gas producers for one of these furnaces require 14 tons of anthracite (a mixture of Nos. 2 and 3 buckwheat), and the waste heat from the furnace gives a little more than 42 h.p. in steam. The boilers are not well adapted for the purpose, as they are much too large for the amount of heat going to them and the area of the tubes is not sufficient to take the gas from two furnaces without causing an objectionable amount of back pressure. The plant was built without any idea of using waste-heat boilers, and it was impossible to place the latter as close to the furnaces as they should be. Furnace and boiler are connected by an underground brick flue in which the temperature of the gas drops about 100°, losing 40 per cent. of its available heat. If the .boilers were close to the furnaces the horse power of each would be 70 instead of 42. Even under these unfavorable conditions the boilers have been very advantageous, as one boiler easily supplies the steam necessary for two batteries of producers. With such low gas temperatures the heating surface of the boilers is, of course, not as efficient and the flue areas need to be considerably larger than for coal firing.

Jan 10, 1913

By George C. Stone

The stack gases from regenerative furnaces lare very seldom utilized for the production of steam. If the temperature of the gases is not higher than 300" C. (572" F.) there is no economy in their use for this purpose, as the amount of available heat is very small and the temperature is so little above that of the steam that the interchange is too slow. With higher temperatures of the waste gases, however, good results can be obtained. At the plant of the New Jersey Zinc Co. (of Pa.) at Palmerton there are a number of return tubular boilers, each 6 ft. in diameter and 20 ft. long, with 96 3.5-in. tubes, which are heated by the waste gases from the spelter furnaces. These furnaces have continuous regenerators heating the air only and the stack gases reach the boilers at a temperature of about 450". The gas producers for one of these furnaces require 14 tons of anthracite (a mixture of Nos. 2 and 3 buckwheat), and the waste heat from the furnace gives a little more than 42 h.p. in steam. The boilers are not well adapted for the purpose, as they are much too large for the amount of heat going to them and the area of the tubes is not sufficient to take the gas from two furnaces without causing an objectionable amount of back pressure. The plant was built without any idea of using waste-heat boilers, and it was impossible to place the latter as close to the furnaces as they should be. Furnace and boiler are connected by an underground brick flue in which the temperature of the gas drops about 100°, losing 40 per cent. of its available heat. If the boilers were close to the furnaces the horse power of each would be 70 instead of 42. Even under these unfavorable conditions the boilers have been very advantageous, as one boiler easily supplies the steam necessary for two batteries of producers. With such low gas temperatures the heating surface of the boilers is, of course, not as efficient and the flue areas need to be considerably larger than for coal firing.

Jan 1, 1914

By James M. Henderson, John B. Pfeiffer

The recently completed liquid sulfur dioxide plant at American Smelting and Refining Co.'s Tacoma copper smelter in Washington last April is one step by the firm to meet ambient air quality standards in the vicinities of its three US copper smelters. At a capital cost of $18.5 million, the liquid SO2 plant will work together with an existing sulfuric acid plant to treat all gases generated by the copper converters. Designed to handle up to 45,000 cfm of converter gas utilizing the Dimethylaniline (DMA) process, this plant is expected to recover about 51% of the total smelter input.

Jan 11, 1974

By E. W. Davis

I . OPERATING TESTS 1. CHARACTER OF ORE UNDER INVESTIGATION On the eastern end of the Mesabi Range, in Northern Minnesota, is a large formation of siliceous rock which contains bands and fine grains of magnetite . The magnetite comprises about 35 per cent. of the rock. Fig.. 1 show's graphically that the tonnage of minus 200-mesh material produced varies directly with the tonnage fed to the mill. There is undoubtedly some limit to this relation, but there seems to be no indication of it at 18 T. per hr. Some of the conclusions drawn from this test are that: (a) The ball-mill is naturally a machine of very large capacity; (b) if it is not possible to deliver a large tonnage of original feed to the mill, a closed circuit should be provided so that the mill may crush its own oversize.

Jan 2, 1919

Meeting, June 26, 1913).-On the petition of 29 members residing in and near San Francisco, Cal., the San Francisco Local Section was established. The territory of the St. Louis Local Section was established to include the following States and parts thereof: All the State of Missouri ; That part of the State of Illinois south of and including the city of Urbana ; That part of the State of Indiana south of and including the city of Indianapolis ; That. part of the State of Kentucky west of and including the city of Frankfort ; That part Of the State of Tennessee west of and including the city of Nashville That part of the State of Arkansas north of and including the city of Little Rock.

Jan 7, 1913

INTERNATIONAL ENGINEERING CONGRESS, 1915.. Announcement. In connection with the Panama-Pacific International Exposition which will be held in San Francisco in 1915, there will be an International Engineering Congress, in which engineers throughout the world will he invited to participate. The Congress is to be conducted under the auspices of the following five National Engineering Societies: American Society of Civil Engineers, American Institute of Mining Engineers, The American Society of Mechanical Engineers, American Institute of Electrical Engineers, and The Society of Naval Architects and Marine Engineers. These societies, acting in co-operation, have appointed a permanent Committee of Management, consisting of the Presidents and Secretaries of each of these Societies, and eighteen members resident, in San Francisco. Thus constituted, the personnel of the Committee 'is as follows:

Jan 9, 1913

By W. S. CAYPLESS, H. O. Hofman, E. E. HARRINGTON

I. INTRODUCTION. LIME-ROASTING is a term proposed by Ingalls 1 for the operation of forcing air under pressure through a mixture of galena and lime at the kindling-temperature with the object of oxidizing lead and sulphur and of fritting or fusing the charge. If, finely-divided galena were treated in this manner without the addition of lime, the heat set free by the oxidation of part of the lead and the sulphur would be sufficiently great to fuse undecomposed sulphide, and thus stop desulphurization. Besides the chemical action that the addition of lime, limestone or gypsum to the charge may have, the admixture has the physical effect that it keeps the particles of galena separated from one another and accessible to the oxidizing effect of the air. At present, three methods of lime-roasting are carried out on a working-scale, the Huntington-Heberlein, the Carmichael-Bradford and the Savelsberg2 processes. In the last, which interests us here, an 8-ton charge is made up of galena, limestone and perhaps some siliceous or ferruginous flux; the whole is crushed to pass a screen with 3-mm. holes and moistened with 5 per cent of water. It is fed gradually into a bowl-shaped converter, 6.56 ft. in diameter, supported by trunnions attached to a truck. On the .bottom the converter has a grate with blast-inlet beneath. In starting, the truck with the converter

Jan 1, 1907

By Harrison Everett Ashley

(Pittsburg Meeting, March, 1910.) Slimes are usually defined as all material passing a certain-sized sieve, which is invariably the finest sieve employed by each metallurgist in his tests; 100-mesh and 200-mesh have been taken as the limits by different writers in recent volumes of the Transactions ; 150-mesh is common practice. The reader of the first two volumes of Richards 1 is impressed by the inflexibility with which all grinding-arrangements are praised or condemned according as they make little or much slime. Until recently, one of the principal aims of the mill-man was to keep down the slimes. He was obliged to have separate apparatus for sand- and slime-treatment. The latter was sometimes puzzling and erratic. Often it was found most .economical to omit treatment of the slimes entirely, or to store them in immense basins or heaps, waiting for possible future improvements in methods of treatment. Recently, improved processes of agitation and filtration have made possible the successful extraction of values from many slimes. The tendency, when the metal is exceedingly finely disseminated, is to cut out all sand-treatment and to slime everything. These processes have been almost entirely mechanical in their conception, and it is the object of the present paper to show that certain chemical considerations may greatly hinder or assist their successful operation. It has long been a source of dissatisfaction to chemists that their analyses fail to be of much help to the clay-worker; that it is a matter of common occurrence for clays of closely identical ultimate chemical constitution to show the widest possible divergence in physical properties. * Published by permission of the Director of the U. S. Geological Survey. Ore Dressing (1903).

Aug 1, 1910

R. M. Raymond, New York, N. Y.—The filling and drawing down of the overhead material was done at considerable depth, which is not the usual method in which it starts at the surface.. R. J. Mechin.— It is a little more than 1000 ft. at El Bordo. The vein above had been caved practically to the surface and some of the ore had been excavated, using underhand and overhand square-set methods. This was far enough away from the shaft to prevent any bad effects. When the sill floor was taken out, to insure the old cave material following down well, we put chutes in the square sets for several weeks until we were sure that the material from above was moving down; on each level above, several crosscuts were driven into the old fill by which we could see the material coming down and thus be sure it was following the first. We had to dynamite it very little because it was dry and dusty. The only trouble was that timber starting from the old square sets would get across the chute and hang up. R.. M. Raymond.—HOW many floors did you operate at once? R.. J. Mechin.—We would operate one floor through the whole length and prepare for the second. F. W. SperR, Houghton, Mich.—Could you have worked it in steps? R.. J. Mechin.—Yes; but working it all on one floor was much better for ventilation. The passage between steps would tend to become heavy and blocked and, as the passages from the mining floor down are usually filled with ore, there would be no way for the air to pass up. By means of doors and fans, air was driven to the extreme end of the orebody through the stope and up the other end; but it could have been worked in steps. F. W. SpeRR.—D the following-up material ever become so heavy that you could see weight on the caps before you had to take out the posts?

Jan 1, 1927

By George C. Coupland

Ecstall Mining Limited, a wholly owned subsidiary of Texas Gulf Sulphur Company, is the owner and operator of the Kidd Creek Mine including the concentrator complex located near Timmins, Ontario. Canada, approximately 450 miles north of Toronto. The mine, concentrator and Timmins form a triangular arrangement with a 17-mile rail link connecting the mine and concentrator and both of these facilities 18 and 14 miles respectively by road from Timmins. A core drilling program in the spring of 1964 established the presence of a large massive sulphide orebody which was to become the Kidd Creek Mine. Texas Gulf Sulphur had been conducting an intensive search for base metal in various parts of Northern Ontario and Quebec since 1957. Of several thousand anomalies detected in airborne electromagnetic surveys, several hundred warranted ground inspection, but only one of more than sixty drilled became a commercial orebody, the Kidd Creek Mine. The geophysical exploration work has been well covered in a paper written and presented by Van Donohoo, presently a Vice-President of T.G.S., at the American Mining Congress in San Francisco in October 1969. GEOLOGY The orebody lies within a series of overturned rhyolitic flows and pyroelastics with a major peridotite intrusive to the east. The hangingwall and footwall are composed chiefly of intermediate volcanics, andesite and dacite. The southern end of the orebody appears to terminate abruptly against greywacke while the north end is bifurcated and the structure obscured.

Jan 1, 1970