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[A Aall, Christian H., M49 D Mgr, American Metal Climax, Inc., 61 Broadway, New York 6, N.Y. Aaroe, S. L., A54 B Sales Mgr, The W. S. Tyler Co. of Can. Ltd., St. Catharines, Ont., Canada Abalos, Teodulo Q., J57 A Foreman, Lepanto Cons. Ming. Co., Mt. Province, Philippines Abbass, G., M55 P. O. Box 680, Hong Kong, China . Abbitt, James M., A54 770 Sole Blvd., Bartow, Fla. Abdullah, M. Y., J53 Dept. of Mines Res. Div., P. O. Box 1016, Tiger Lane, Ipoh Perak, Malaya Able, John F., Jr., J53 A Ming Engr, USA SIPRE 1215 Washington Ave., Wilmette, Ill. Abell, Leo M., M31 B Conct Supt, Phelps Dodge Corp., Morenci, Ariz. Abenius, Hakan Wilhelm, M52 A Mng Dir, Stora Kopparbergs Bergslags AB, Falun, Sweden Abenoroth, Harry F., A57 Natl. Carbon India Ltd., 18A Brabourne Rd., Box 217, Calcutta, India Abercrombie, Harry W., J56 1645 Camphor Dr., Lakeland, Fla.]

Jan 1, 1961

By Elmer R. Kaiser

G. A. Vissac (Consulting Engineer, Vancouver, B. C.) —Some of the data presented in this paper, in connection with cost studies of washed coals, should be clarified and qualified. Washing a raw coal down to a low ash content may mean higher losses in refuse, but the cost of the operation may be more than compensated by the increased value of the resultant product. However, careful engineering and accurate machinery are required to insure maximum profits. Washing at a low gravity separation demands a very accurate automatic process, chiefly when the small sizes of coal are being handled. Coal consumers today are buying mostly on a Btu basis, cognizant of the fact that low ash contents result in lower installation costs and in savings in handling and transportation charges. The attached Table X gives the actual balance sheets of the various cleaning operations corresponding to various ash contents for the two coals presented in the paper, using the old technique of a two-products separation. or the new technique, now commonly used in Europe, of a three-way separation made possible by new methods and new equipment. Savings in capital costs, handling, and transportation have been calculated on the basis of a delivered cost f.O.b. plant of $10.00 per ton of coal at 16.5 pct ash (actual 1953 average price reported by Consolidated Edison, N. Y.), and of $3.50 at the mine also for 16.5 pct ash coal. In both cases this corresponds to values of 126 and 4.26 per 1 pct of combustible and per ton, respectively, on delivered and on at the mine prices. As an example, the middle western coal at 16.5 pct ash, raw, washed down to 4 pct ash in a two-way process will give 53.75 pct of clean coal at 4 pct ash and 46.25 pct of refuse at 31 pct ash. The value of the losses will be 0.4625x(100—31)x0.042 = $1.34. Add the cost of washing, capital, and operation, which is $0.35. The total cost will then be $1.69. But with a three-ways separation we will have 53.75 pct of first-grade coal at 4 pct ash, 37.25 pct second-

Jan 1, 1955

By T. S. Blair

I feel a certain sense of responsibility in bringing before you the subject of the direct process in iron manufacture. I am aware that, in such a body as I have now the honor of addressing, there are few who are not already so well informed upon its past history that it would be a weariness to them to listen to anything else than an account of practical success. Yet, to claim that success involves so much that, if I do not make good my claim, I deservedly expose myself to severe criticism. The whole literature of the art, so far as it relates to the direct process, is, up to this time, but a history of failure. It is safe to say that more money, time, and talent have been fruitlessly spent in the pursuit of this object than in all the other unsuccessful efforts in the whole line of iron metallurgy. A distinguished authority in patent law has remarked that " the invention records of the United States and of foreign countries are filled with the waifs and abandoned relics of these abortive struggles." Dr. Percy, whose great work may be taken as an epitome of all that was worth mention, whether useful or curious, in pig-iron metallurgy, up to the date of its publication (1864), after giving elaborate accounts of various attempts at the direct process, condenses his own opinion of all that had been then effected, into a brief but summary comment upon a pamphlet of one of the sanguine inventors who had said: "It is evident that the present mode of working iron

On Tuesday evening, February 21st, a reception of visiting societies was held in the Windsor Hall. Hon. George Irvine, Q. C., President of the General Mining Association of the Province of Quebec, occupied the chair, and, after welcoming the guests of the occasion in the name of that Association, introduced Mayor Desjardins, who expressed a cordial greeting for the city of Montreal. After appropriate acknowledgements from the President and the Secretary of the Institute, President Birkinbine delivered his presidential address. The first regular session of the Institute was held on Wednesday morning, February 22d, in the Physics Building of McGill University, where all succeeding sessions were also held. The annual report of the Council was read, as follows : Annual Report of the Council. In accordance with the rules, the Council makes the following report to the Institute:

Jan 1, 1893

It has been suggested that it would be a desirable feature in connection with the Chicago meeting of the, Institute in September to arrange for a return trip for the fuel men through the coal fields of Illinois, Ohio and Pennsylvania, stopping at various points and possibly touching also Kentucky. Perhaps the petroleum men would be interested in a similar trip and might join them stopping off at different points to visit these oil fields. If the members who would-be interested in such a trip will advise the Secretary before the first of June, indicating their desired stopping points, steps will be taken to perfect arrangements accordingly.

Jan 5, 1919

By Alexander B. Morris

Studies such as the investigations into the solubility of gases in crude oil under various conditions, which have been carried on during the past three or four years, are very interesting from an academic point of view, but this consideration alone is hardly sufficient to warrant the large contributions from the industry necessary to maintain them. Some definite benefit to the industry as a whole should be forthcoming. The purpose of this paper is to direct the attention of company engineers, and company executives, to some of the ways in which the information gained from these studies can be made directly profitable. This work has two principal economic aspects. One affects the investment budget, and through it the financial requirements of the companies. The other affects operations, and through this course is reflected in current earnings. It will be shown that, as a direct result of the investigations into gas solubility, undertaken in the recent past by various investigators, it is now possible: 1. To determine more accurately the amount of reservoir oil originally present. 2. To obtain closer control on operating conditions, to effect more economical recovery. 3. To predict earlier and more dependably when and how much surface lifting equipment will be needed. 4. To reduce, or entirely avoid the very large investment in gasoline recovery equipment now frequently found necessary. 5. To control the gravity of the pipe-line oil so as to secure the greatest possible revenue from the products of the well. 6. To effect the recovery of a large amount of gasoline now wasted while the practicability of a gasoline recovery system is being decided. 7. To plan operations, by comparison with the history of old properties operated without this new information, so as to avoid the mistakes of ignorance made in the past. These points will be discussed in the following pages, though not necessarily in the order stated. There is so much overlapping of the points themselves, and of the data from which they have been drawn as conclusions, that to treat them in any particular order would require

Jan 1, 1935

By D. I. Bardos, A. M. Bardos, Paul A. Beck

The approximate effective silicon radii in ternary Laves phase alloys with transition elements and silicon were found to range between 1.16 and 1.21A, i.e., considerably smaller than the atomic radius calculated for elemental silicon. The atomic radii were found to increase with the size of the transition element atoms in the structure. It has been noted by Aronsson1 that silicon in solid solution in iron, cobalt, and nickel has an effective CN 12 atomic radius of approximately 1.20Å, a value very much smaller than the CN 12 radius of 1.34Å derived from the interatomic distances in elemental silicon.7 The unusually short metal-silicon interatomic distances in transition element monosilicides and disilicides have been also pointed out by various investigators.1 A similar tendency was observed by Nevitt in Cr3O type silicides.2 Recent work on Laves phases in ternary systems of silicon with transition elements4"8 suggested that extensive Laves phase fields may occur in such systems.8 It has been pointed out by Laves7 that the MgCu2 and MgZn2 type structures lend themselves particularly well for the determination of the effective radii of the component atoms. In these AB2 phases the B atoms are arranged in close packed straight lines, and their distances are related in a simple manner to the lattice parameters.8 The present work was undertaken in order to find out whether or not the B transition element in such AB2 Laves phases can be replaced to an appreciable extent by silicon. In cases where extensive substitution proves to be possible, the "average atomic radius for the B site" at various silicon contents was to be determined, and the effective atomic radius of silicon calculated by extrapolation to complete replacement of the B component by silicon. The following ternary systems were studied: Ti-Mn-Si, Ti-Fe-Si, V-Co-Si, V-Ni-Si, Nb-Fe-Si, Nb-Co-Si, Ta-Fe-Si, Ta-Co-Si, and Mo-Fe-Si. In all of these alloy systems, the Laves phase solid solutions were found to extend over a considerable range of silicon content. As previously reported,4"8 in the V-Co-Si, V-Ni-Si, and Mo-Fe-Si ternary systems Laves phases do occur, even though there are no corresponding binary Laves phases. In stabilizing the Laves phase, silicon acts as if it were decreasing the effective electron concentration of the alloy.8 A more detailed study of the boundaries of the Laves phases in the V-Co-Si and V-Ni-Si systems has been made and will be published elsewhere. In both cases, the elongated Laves phase fields extend parallel to the B-Si side of the composition triangle, clearly showing that silicon is substituting for cobalt, respectively, nickel over a wide range of compositions. The binary Laves phases NbCo2 and TaCo2 have the cubic MgCu2-type structure. It was found that, in both ternary systems with silicon, again the MgZn2-type hexagonal Laves phase is stabilized and that this phase extends to high-silicon contents. In each ternary system at least three Laves phase alloys of the composition A(B1_xSix)2 were used, x here denoting the fractional substitution of the B-transition element atoms by silicon. The alloys, listed in Table I, were prepared by arc melting in argon. Each specimen was water quenched after a homogenizing anneal of 3 days at 110(FC, except for the Mo-Fe-Si alloys, which were annealed at 1200°C. Metallographic examination showed that most of the homogenized alloys consisted of a single phase, although some had minor amounts of a second phase, as shown in Table I. X-ray diffraction patterns were prepared using an asymmetrical focusing camera of large resolution and Fe Ka radiation. The patterns were indexed, and the lattice parameters of the hexagonal Laves phases were determined from the available diffraction lines of highest indices: (213), (205), and (313). The lat-

Jan 1, 1963

The American Society of Mechanical Engineers extends an invitation to members of the Institute to participate in an exceedingly interesting excursion on Saturday, November 11. Permission has been secured for a visit to the plant of the Electric Boat Co. at New London, Conn. There will be run a special-test on a high-power 8-cylinder, 4-cycle Diesel engine. A large number of submarine and other engines in various stages of construction will be seen, also the boring of torpedo tubes, cylinders and other equipment for submarines. The drafting rooms and foundry mill also be open for inspection. The party will have an opportunity to see at close range the submerging of several submarines, and an attack on a vessel on the surface, an exhibit which is being arranged by courtesy of Rear Admiral A. W. Grant, who is in command of the submarine forces of the United States. The Boston members will leave South Station on train No. 7 at 8.30 A. M. Those from Providence will board this train at 9.36 A. M. The Worcester members will leave on train No. 745 at 8.36 A. M. The New York contingent will leave the Grand Central Terminal at 8.31 A. M. on train No. 8. This train will leave New Haven at 10.30 A. M. Upon arrival at New London, each group will go directly to the Mohican Hotel, where a "get-acquainted" luncheon will be served

Jan 10, 1916

By Byron M. Bird

JIGGING is the stratification of a mass of solid particles in upward pulsations of water or in alternating upward and downward pulsa¬tions. The stratification usually is effected in a rectangular open¬top container having a perforated bottom through which the pulsations of water are applied to the materials to be separated; in separating coal, to a mass of coal and refuse. Jigging usually is a continuous process involving three steps: (1) the reception of the raw coal, (91) the stratification of the coal and refuse so that the refuse settles to the screen plate, and (3) the overflow of the cleaned coal and the withdrawal of the refuse collected on the screen. The jig is the most universal washer ever devised. It is handling in practice a wide range of closely sized coals and ores, mixed sizes of coal from 8-in. to 0 through %-in. to 0, and mixed sizes of ores down to %3 O-in. to 0 and even smaller. It is treating materials ranging in specific gravity from that of gold at 19 to that of coal at 1.30. It is handling feeds in which the proportions of high-gravity materials range from 90 per cent or higher, as for some iron ores, to 10 percent or less for some coals. It is handling feeds containing all shapes of particles-round, rectangular, and flat. It is handling simple separation problems and difficult separation problems. Thus, it is an almost universal separating device. One might add that it has been one of the most misunderstood types of washers, from both a theoretical and a practical point of view. Although con¬siderable progress has been made in coal jigging in the past 10 years, the jig probably has more unexplored possibilities than any other type of washer. In this chapter the object has been to treat the jigging process in a practical manner and to give information that will help the reader to improve his particular operation. Inasmuch as performance data from operating plants would contribute little of value, none has been given. Instead, the emphasis is upon jigging principles as a foundation for attacking the problems that arise. These principles are in reality tenta¬tive conclusions from research in the field of jigging during the past 10 years and most of this chapter should be regarded as a progress report on an investigation still under way.

Jan 1, 1943

By C. R. Van Hise

PART I.-GENERAL PRINCIPLES. [ ]

Jan 1, 1902

By Elmer W. Pehrson

NINETEEN FORTY-SIX was an eventful year for the mineral industries. Perhaps the most significant development was the socialization of industry in Great Britain, initiated in 1945 but carried to fruition in the coal industry in 1946. On Jan. 1, 1947, management of the coal industry will be vested in a National Coal Board, responsible to the Ministry of Fuel and Power. A sum of £164,660,000 has been provided to compensate private owners for assets transferred to the Board. The British coal industry has been a problem for many years. Production has declined to a point where serious shortages of fuel for domestic needs have developed. Exports have dwindled to a small fraction of the previous trade. Costs have increased greatly, and quality has deteriorated. The industry's physical plant has not kept pace with the rapidly mounting wage scales in recent years. Some claim that the best and most accessible coal reserves of Britain are heavily depleted. The industry has been harassed by difficult labor problems, including bad morale among the workers and a shrinking labor force.

Jan 1, 1947

By P. H. Metzger, D. W. Fuerstenau

The activation of sphalerite was found to occur at a much lower rate with Pb++ then with Cut++ or Ag+. To prevent activation with Pb++, the ratio [m in solution must approximate 103. An example is given illustrating how this condition is met in practice through the addition of zinc sulfate and soda ash. In selective lead-zinc flotation, the mill operator, especially the one who is concentrating a partially oxidized ore, often must add zinc sulfate and/or soda ash for effective depression of the sphalerite. In the present paper the authors show how this practice prevents the activation of sphalerite in the presence of Pb++. A number of years ago Gaudin (1) postulated that Zn++ might control the activation of sphalerite with Pb++ through competitive adsorption. However, recent experimentation has shown the activation of sphalerite with Ag+ and Cut++ to be a chemical reaction in which silver or copper ions replace zinc in the sphalerite lattice through the formation of a more insoluble sul-fide (2,3,4) Thus, if activation with Pb++ is similar to that with Ag+ or Cu t+, zinc salts should control the activation of sphalerite not through competitive adsorption but because the ratio of [zn++/Pb++] in solution regulates the extent of the chemical exchange between Zn++ and Pb++ in the solid phase. The objective of this investigation has been to study the kinetics and equilibrium conditions for the uptake of Pb++ by sphalerite and to investigate the prevention of lead activation with zinc salts. BASIC PRINCIPLES Sphalerite activation has been shown to be a replacement reaction wherein a less soluble compound is formed at the expense of the more soluble zinc sul-fide (2,3,4) For example, if sphalerite is placed in an aqueous silver nitrate solution, ZnS gives to the solution more S= than can exist together with Ag+, and hence the following reaction takes place: ZnS + 2 Ag+? Ag2 S + Zn ++; k = [zn ++]/[Ag ++]2 = 10 26 (1) Therefore, ZnS will dissolve in the presence of Ag+ and activation of sphalerite with Ag+ will proceed after monolayer coverage by solid state diffusion until equilibrium conditions are reached in the system (2, 4) Because of the large difference in the solubility of ZnS and Ag2S, zinc salts cannot affect the reaction unless a complexing agent, such as cyanide ions, is present to complex Ag+ more tightly than Zn++ . By complexing Ag+ and Zn++ in solution, the uptake of Ag+ by sphalerite can be regulated by controlling the ratio m. . Experimentally (2) it was found that the activation of sphalerite by Ag+ could be prevented through the addition of NaCN if this ratio reached a value of approximately 10 26. The mechanism of sphalerite activation with copper salts is given by the following reactions: ZnS + Cu ++ ? CuS + Zn + + ; (2) k = [Zn++]/[Cu++] = 10 11 ZnS + Cu + ? Cu2S+ Zn++; (3) Experimentally Mao (3) found that the activation of sphalerite with Cu++ or Cu + was prevented if the ratios expressed in Equations 2 and 3 were approximately l09 and l022, respectively, with cyanide ions as the deactivator. Although zinc salts do not affect the activation of sphalerite with silver or copper ions in the absence of a complexing agent, activation with lead ions theoretically can be controlled by the addition of zinc salts because of the relatively small differences between the solubility of ZnS and PbS (5). Equilibrium

Jan 1, 1961

By G. G. Brown

Enthalpy-entropy diagrams are presented for natural gases of 0.6, 0.7, 0.8, 0.9, and 1.0 gravity over the pressure range of 5 to 10,000 Ib. per sq. in. and temperature range of 32º to 700°F. The charts indicate directly the work requirement and temperature rise for adiabatic compression or temperature change for free emansion of natural eases. Computation and Uses of Charts The Mollier diagram (Fig. 4), in which the enthalpy (heat content) is plotted against the entropy with lines of constant temperature, pressure,, and in some cases volume, has been found most convenient when dealing with the compression, expansion, and flow of fluids. In dealing with the flow of fluids, the sum of the increase in the enthalpy, AH, plus the increase in kinetic energy, AM —, plus the increase in potential energy, ?MZ, representing the total increase in energy of the fluid in flow, is equal to the sum of the heat q, and work added, —w, to the fluid while flowing between the entrance and exit of the flow system. AH + AM— + ?MZ = q-w [1] In cases where there is no significant change in potential energy or in kinetic energy (velocity), it follows that the increase in enthalpy is equal to the total energy supplied to the fluid. Under such conditions' the changes in the property of the fluid as it flows through a throttling valve, choke, or any other similar arrangement, may be read directly from the enthalpy-entropy diagram by following a horizolltal line between the known pressures' When compressing Or expanding a gas by means of a Or or engine in which no heat is added to or subtracted from the gas, but only work done, the changes in the properties of the gas may be determined along a vertical line of constant entropy between the entering and exit pressures. The power required for the compression of the gas may be readily determined by converting the increase in enthalpy into the desired units. The enthalpy-entropy diagram for natural gases is to the gas engineer what the steam diagram is to the steam-power engineer. For this reason it would be extremely convenient if a reasonably satisfactory enthalpy-entropy diagram could be prepared as a function of the gravity of the gas. A careful study of the known properties of natural gas indicate that this is possible. The effect of temperature upon the enthalpy at constant pressure is expressed as the "heat capacity" or "specific heat" of the gas. The best available data for natural and petroleum refinery gases indicates the relationship shown in Fig. I. From this it is clear that the specific heat of natural gases is a function only of the gas gravity and the temperature at atmospheric pressure. The effect of pressure on the enthalpy of natural gases is dependent upon the pressure-volume-temperature relationships,

Jan 1, 1945

By M. R. Geer

Coal washing assumed an important role in the mining industry of the Pacific Northwest long before washing practice became firmly established in the Appalachian field. A Scaife washer was operated in the state of Washington in 1887; and by 1927, the fist year for which complete statistics were compiled, nearly a third of the state's coal production was washed, in comparison with only about 5 pct for the country as a whole. Mechanical preparation was adopted in Alaska in 1922 in a plant constructed by the United States Navy at Chickaloon to provide bunker coal for naval forces operating in northern waters. Many of the coal beds mined in Washington and Alaska contained more impurities than those mined elsewhere, and this circumstance contributed to the early interest in mechanical cleaning. A much more important factor, however, was the inclination of the coal beds. With steeply pitching beds, hand sorting by the miner at the face is impossible; consequently, all material must be loaded and dealt with on the surface, just as is now proving the case with mechanical mining of flat beds. Thus "full-seam" mining afforded the same stimulus to the early development of coal washing in the Northwest that - it is providing under mechanization in the rest of the country today.

Jan 1, 1949

By T. A. Rickard

The dictionary defines 'jargon' as "barbarous or debased language". This description does not suffice. Quiller-Couch has said, it is "a kind of writing which, from a superficial likeness, commonly passes for prose in these days, and by lazy folk is commonly written for prose, yet actually is not prose at all ". The two main vices of jargon, he says, are "that it uses circumlocution rather than short straight speech", like the Babu who reported his mother's death by saying: "Regret to inform you, the hand that rocked the cradle has kicked the bucket ". Its other chief' vice is that "it habitually chooses vague woolly abstract nouns rather than concrete ones", like the newspaper statement; "He was conveyed to his place of residence in an intoxicated condition", instead of saying, "He was carried home drunk ". Jargon is "an infirmity of speech", it is not journalese, but akin to it. "Like respect- ability in Chicago, jargo4 stalks unchecked in our midst" and renders much technical writing ridiculous. It deals in periphrasis instead of going straight to the point, it loves the abstract rather than the concrete, it dabbles in words of sound rather than of meaning. Avoid it, despise it., if you purpose earnestly to write well. "III literature as in life he makes himself felt who not only calls 4 spade a spade but has the pluck to double spades and re-double." * Jargon is rampant in technical publications. Catalogues and other advertisements are conspicuous offenders, but with these the critic is not concerned, except in so far as such 'write-

Jan 1, 1931

By Ralph Sweetser

THE Round Table. on Qualities of Pig Iron, under the auspices of the Joint Committee on Qualities of Pig Iron, which is made up of members of the American Institute of Mining and Metallurgical Engineers, the American Foundrymen's Association, the American Society for Testing Materials, the Gray Iron Institute, and the. Malleable Iron Institute, was held at the Palmer House, Chicago, Ill., on Oct. 1, 1935. PROCEEDINGS R. H. SWEETSER,* New York, N. Y.-Seven years ago last June we had a round table on qualities of pig iron1, and at that time the foundrymen were out with their battle-axes for the blast-furnace men, and the open-hearth men were doing the same thing. After that meeting there was really a determined effort to find out about the qualities of pig iron, and great progress has been made all along the line. This afternoon we want to have a frank discussion of the qualities of pig iron, whether it is the molten pig iron going into the steel plant, or cold pigs going to the different foundries. We ought to hear something from Dr. J. T. MacKenzie, who is chairman of the Joint Committee, and from Mr. R. E. Kennedy, the tech-nical secretary. J. T. MACKENZIE, t Birmingham, Ala.-As a result of that meeting in Chicago, there was considerable agitation in the Foundrymen's Association to develop a set of tests for pig iron. One of the difficulties was that nobody talked the same language on shrinkage, draws, live iron, dead iron, and so forth, which were the main com-plaints against pig iron. By request of a committee of the Foundrymen's Association, the Bureau of Standards ran a comprehensive set of tests that did develop the prin-ciples governing the optical pyrometer as applied to cast iron and pig iron. Then the Bureau went on further with the fluidity test, and developed a method for the absolute changes of volume at the freezing point.

Jan 1, 1936

By Edward Keller

Jan 1, 1906

By M. W. Bartley, Hugh M. Roberts

Substantial deposits of Bessemer hematite have been found recently by drilling beneath Steep Rock Lake, Ontario, which is situated in the northern part of the Lake Superior Region. It will be practicable to divert the waters flowing into this lake and develop open pits on the upper pert of two large ore bodies by damming off and pumping out the water in the part of the lake in which they occur. Ultimately, the bulk of the ore will be mined by underground methods. Owing to the generally massive nature of the rocks in the area, no underground flows of major consequence are anticipated after diversion of the lake. The Steep Rock deposits are attributed in origin to hydrothermal replacement. They were formed, for the most part, along an unconform-able, brecciated contact between the Steep Rock limestone and an overlying younger volcanic series, The replacing solutions came in as igneous after-effects, following upon the intrusion of basic igneous rocks that invaded the hanging-wall volcanics. It is believed that this took place in a geological period roughly equivalent to late Middle Huronian, which was the period when the most extensive iron-bearing rocks of the Lake Superior Region were formed. Comparison is made with other deep-seated iron-ore bodies in the Lake Superior Region, the origins of which are ascribed in the discussion to hydrothermal replacement. Introduction Under the waters of Steep Rock Lake, Ontario, situated on the Canadian National Railway, 142 miles west of Port Arthur, the presence of three ore zones containing red and brown Bessemer hematite has been established. These were discovered and have been partly explored by means of diamond and churn drilling, The positions of the ore zones, designated as A, B and C, are shown on the accompanying maps and cross sections. This exploratory work, begun in 1938 by Joseph Errington* and Julian G. Cross, has been carried on by Steep Rock Iron Mines Ltd., and was continued during the winter of 1941-1942. For more than 60 years explorers have known that large quantities of hard hema. tite float of good grade existed along the south shore of Steep Rock Lake, and the presence of ore beneath the lake was inferred by many early geologists and explorers. Despite numerous previous attempts to find ore in place, actual discovery awaited the recent period of intensive exploratory effort in Canada. The results obtained in the drill holes put down since 1938 by steep Rock Iron Mines Ltd. are not only of interest, in themselves, to those concerned with the development of ore deposits, but, taken in connection with the surface exposures of adjoining formations, they form the assemblage of facts from which the geological reasoning in this paper proceeds; accordingly, they are set out here as briefly and exactly as may be.

Jan 1, 1949

By M. W. Bartley, Hugh M. Roberts

Substantial deposits of Bessemer hematite have been found recently by drilling beneath Steep Rock Lake, Ontario, which is situated in the northern part of the Lake Superior Region. It will be practicable to divert the waters flowing into this lake and develop open pits on the upper pert of two large ore bodies by damming off and pumping out the water in the part of the lake in which they occur. Ultimately, the bulk of the ore will be mined by underground methods. Owing to the generally massive nature of the rocks in the area, no underground flows of major consequence are anticipated after diversion of the lake. The Steep Rock deposits are attributed in origin to hydrothermal replacement. They were formed, for the most part, along an unconform-able, brecciated contact between the Steep Rock limestone and an overlying younger volcanic series, The replacing solutions came in as igneous after-effects, following upon the intrusion of basic igneous rocks that invaded the hanging-wall volcanics. It is believed that this took place in a geological period roughly equivalent to late Middle Huronian, which was the period when the most extensive iron-bearing rocks of the Lake Superior Region were formed. Comparison is made with other deep-seated iron-ore bodies in the Lake Superior Region, the origins of which are ascribed in the discussion to hydrothermal replacement. Introduction Under the waters of Steep Rock Lake, Ontario, situated on the Canadian National Railway, 142 miles west of Port Arthur, the presence of three ore zones containing red and brown Bessemer hematite has been established. These were discovered and have been partly explored by means of diamond and churn drilling, The positions of the ore zones, designated as A, B and C, are shown on the accompanying maps and cross sections. This exploratory work, begun in 1938 by Joseph Errington* and Julian G. Cross, has been carried on by Steep Rock Iron Mines Ltd., and was continued during the winter of 1941-1942. For more than 60 years explorers have known that large quantities of hard hema. tite float of good grade existed along the south shore of Steep Rock Lake, and the presence of ore beneath the lake was inferred by many early geologists and explorers. Despite numerous previous attempts to find ore in place, actual discovery awaited the recent period of intensive exploratory effort in Canada. The results obtained in the drill holes put down since 1938 by steep Rock Iron Mines Ltd. are not only of interest, in themselves, to those concerned with the development of ore deposits, but, taken in connection with the surface exposures of adjoining formations, they form the assemblage of facts from which the geological reasoning in this paper proceeds; accordingly, they are set out here as briefly and exactly as may be.

Jan 1, 1949

By Gordon MacVean

THE adoption of rock dusting, as a safety measure, has made notable progress in the West Virginia coal mines since May, 1925. At that time there were but two mines in the State that were thoroughly rock dusted, mines No. 2 and No. 12 of the Boone County Coal Corp., at Sharpless. Since then it is probable that 75 per cent of the coal operators in the State have given consideration at one time or another to rock dusting. This growth of interest followed the meetings of the various mining institutes all over the country, during the summer of 1925, at which papers were presented, drawing the attention of the coal mining operators to the merits of this safety measure. Yet outside of the experience with rock dusting at the Old Ben Coal Corp., of Southern Illinois, and the Carbon Fuel Co., of Rains, Utah, there had been no actual occurrence in the coal mines of the United States, which could be taken as positive evidence of the efficacy of rock dusting in the prevention of the propagation of coal dust explosions. The U. S. Bureau of Mines, however, had run innumerable tests under conditions which closely approximated actual coal mining conditions and had clearly shown that rock dusting was effective.

Jan 1, 1926