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By T. B. Nolan, R. N. Hunt

In terms of present metal prices, analysis of extant records of the Eureka district indicate past production of the magnitude of $200,000,000 in recovered silver, lead, and gold. Production to date has been thoroughly oxidized ore from massive replacements, fissures, manta, and pipe-like bodies-in large part from the massive Eldorado (middle Cambrian) and Hamburg (middle to late Cambrian) dolomite horizons. In the productive area of about 6 square miles carbonate rocks comprise 80 per cent of the section, which includes early Cambrian to late Ordovician horizons. Four-fifths or more of the district's production came from a block of Eldorado dolomite in Ruby Hill that was moved in over younger horizons on strands of a regional thrust fault. The lower 500 to 600 feet of the block was much fractured and brecciated and became host to the ores. The Ruby Hill fault, a late normal fault, limits the Ruby Hill block of dolomite on the north for its entire length of nearly a mile and terminates the downward extent and exploitation of its ores. It introduced an hiatus of some 40 years in the district's development. Drilling of the past 20-odd years, followed by underground work, has now exposed the down-faulted extension of the Ruby Hill block of Eldorado dolomite and its contained ores, dropped 1800 feet in a dip shift to depths beneath the surface of 2000 to 3000 feet. The ores at depth are the sulfide counterpart of those mined in early years on the footwall side of the fault. The ores of the district may be attributed to the same source as the intrusive quartz diorite outcropping in a limited way south of Ruby Hill but found at depth elsewhere in drill holes. The long north-south axis of the district, its anticlinal structure, its major faults, and the distribution of the intrusives and, in their relation to the surface, the ores themselves, all suggest that erosion has not cut deep enough to expose the extent of intrusives and the ores consequent upon them.

Jan 1, 1968

By Kirtley F. Mather

FROM almost every point of view, petroleum was "strategic mineral number one" during the World War that ended in 1945. Even the spectacular advent of the atomic bomb in the final days of the conflict did not displace it from its position of prime importance, although within a few years uranium will almost certainly be the "number one" material in the minds of military strategists, if it is not even now in that position. But both as fuel and as raw material for chemical industries, petroleum will hold the center of the stage for many years to come. Hardly any other substance illustrates so fully the manner in which science and technology may be combined to achieve the utmost success in contributing to human efficiency and comfort. Fundamental to any understanding of the problems implied by my topic

Jan 1, 1948

By P. H. Dudley

A Discussion of the Paper of Prof. Howe. (Bi-Monthly Bulletin, No. 14, March, 1907, pp. 169 to 274.) P. H. DUDLEY, New York, N. Y. (communication to the Secretary*) :-The characteristics of Prof. Howe's metallurgical papers are, that he is able, from the mass of confusing evidence on the subject, to make an analysis and present hypothetical and essential principles in concrete form for consideration and discussion. I can appreciate, from the practical side of the subject, the arduous labor of collecting and investigating the data that is essential to prepare the paper. Much of the data necessarily came from material of preceding years. of manufacture in which there was allowed time for chemical reactions of the recarburizer, and for the elimination of the oxidation-products before teeming the ingots. This condition gave a favorable tinge-element to free the metal from slag- and other impurities, but, in allowing the. ingot to cool before charging in the furnace, the time-element entered as a detrimental factor in the development of the pipe or shrinkage-cavities, which gave an ingot-structure deficient in soundness. The interpretations from such material must be made with due allowances for the methods of manufacture, and must be given proper weight, as general facts, in subsequent arguments. The difficulties under which investigators labor are not easily surmounted in differentiating between reliable and unreliable data incident to variables of methods of manufacture, chemical composition of the alloys of steel, mediocre practice and that of the highest state of the art. Modern practice and large outputs in Bessemer steel have reversed the effects of the time-element-by cutting short the chemical reactions of the recarburizer and the elimination of

Jan 5, 1908

By FOSTER HEWElT

THE scope of this paper is the description of two districts in Peru in which deposits of vanadium have been found, and the consideration of much laboratory-work that I and others have done to determine the nature of these deposits. It is with regret that I present some of the data in a state of evident incompletion, particularly the analyses of a few of the minerals, which leaves some doubt as to whether the true nature of the minerals is understood. I make no apology, however, since in this case, as in many others referring to ore-deposits, conclusive opinions cannot be stated until a great amount of work has been done, and the deposit has been thoroughly exploited. I believe that the data and the tentative conclusions here presented indicate a unique and interesting condition which may assist others in work along similar lines; and further, what is of more practical importance, stimulate a search for a metal which, though long considered rare, is probably so merely because proper care has not been taken to recognize it. An excellent bibliography on the occurrence of vanadium in nature is given by F. W. Clarke in his paper, Data of Geo-chemistry;1 and in the preparation of this paper I have consulted many of the references contained in the Bibliography of the Chemistry of Vanadium, by M. Moissan.2 A brief review of the subject having special reference to the metallurgy of vanadium is contained in the small book by P.. Nicolardot.3 One of these vanadium-deposits has already been briefly

Mar 1, 1909

By AIME AIME

THE program of government drilling, conducted jointly by the U. S. Geological Survey and the Bureau of Mines, has demonstrated the presence in Texas and New Mexico of potash-bearing beds of considerable importance. Information regarding the ex- tent and location of the potash deposits as presented at the non-metallic sessions was of great interest to many engineers. These subjects will be covered in greater detail in later paragraphs. The first session, with about 50 in attendance, convened at 10 a.m. on Feb. 18, with Oliver Bowles, chair- man of the Committee on Non-Metallic Minerals, pre- siding. The first paper was on "Soapstone Mining In Virginia," presented by C. W. Ryan of Lynchburg, Va. The nature and extent of the soapstone deposits of Nelson County were described in some detail. In origin, the soapstone is undoubtedly related to a basic peridotite rock though its mode of formation is some- what uncertain. This main soapstone deposit occurs in three veins, the western, middle, and eastern, the middle vein being of greatest economic importance. Methods of stripping, quarrying and milling the rock were described and the uses of soapstone were enum- erated. In discussing this paper, C. P. Berkey, of Co- lumbia University strongly favored the theory of igneous origin of the soapstone and the need for further detailed geological study. J. L. Gillson of Cambridge, Mass., stated that the Vermont and New York talc deposits were always associated with characteristic minerals, such as, a chlorite of one particular variety, siderite, amphibole, magnetite, and biotite. C. H. Behre of Cincinnati, Ohio, raised the question of parallelism in the soapstone structure and Mr. Ryan stated that such parallelism was in evidence in some parts of the deposits. H. A. Wheeler of St. Louis, Mo., also took 'part in the discussion.

Jan 1, 1929

By Salinger, Herbert

WITH the large amount of metallurgical re- search work now being done and the constant effort of the engineer to effect economies of operation, I think it is a safe prediction that the next few years will see a great change in the handling of mine products. The well-managed mine, with sufficient ore reserves to warrant the necessary plants, will increasingly call upon the metallurgist and chemist for the solution of its problems. Shipping sorted ore or concentrate to the nearest smelter will not be the course followed. From ore to metal, or at least to a product directly salable to the consumer, will be the practice followed. As a consequence, mine managers will be increasingly interested in metal trade problems. By metal trade I mean the buying, selling, shipping, handling, and all the practices, forms and customs that go to make up the trade.

Jan 1, 1928

THERE have been two important accomplishments of the Truman administration; the Hoover Commission report on inefficiency and waste in government and the report of the Paley Commission on the natural resources of the United States. Both reports are in the interest of the American people and should transcend the boundaries of political parties. Both reports are starting points for the formulation of policies which must be continuously revised to meet changing conditions. Regardless of the outcome of the election the principles embodied in these two great documents must be kept alive. The Paley report is right in our own bailiwick of mineral raw materials and it behooves us to study it carefully as our responsibility to posterity. To those in the mining industry who have limited their field of observation to moving rock or to metal prices it may come as a surprise that our production of such staples as copper, lead, and zinc has fallen behind increased requirements to the point that substantial tonnages must be imported. Iron ore is next on the list and everybody knows that such metals as tin, tungsten, chromium, manganese, nickel, and cobalt are imported almost exclusively. The crisis in raw materials pointed up by the Paley report has been reported annually by Elmer Pehrson and others to small gatherings at the Mineral Economics Division sessions at the Annual Meeting for as long as we can remember. In September 1949, the United Nations Economic and Social Council held an international resource conference at Lake Success which disclosed these same grave conclusions: - Consumption of raw materials is multiplying at an alarming rate, faster than discoveries or replacements are being made. - Production has been wasteful and utilization lavishly beyond enginee¬ing and practical requirements. - Industrialized nations are depleted and many raw materials consumed by industry are not found in the industrialized countries. - Nations formerly exporters of raw materials are increasingly building their own consuming industries. - Political forces in the world are limiting access to raw materials. The Paley Commission selecting the quarter century, 1950 to 1975, to project raw material requirements for the United States, pointed out obstacles to meeting these requirements, and made recommendations for procurement. It is not important that we disagree that cobalt consumption will reach 344 pct of present, or fluorspar 187 pct when iron and ferroalloys are only expected to increase 75 pct. What is important it that the fabulous appetite of the United States for mineral raw materials has consumed more since World War I than was consumed by the entire world in all recorded history prior to 1914. And, unless the people of the United States are satisfied to remain at their present standard of living (which is unthinkable) this consumption is correctly plotted by the Paley Commission as continuing to expand. If the U. S. is to continue on a course of progress, it must procure raw materials wherever it can at the lowest possible cost. Natural resources are clearly an area in which the broadest cooperation between industry and government must exist to achieve efficient exploitation, economic consumption, and expansion of sources of supply. The message of the Paley report requires action comparable to that of the North Atlantic Pact. Its implication is as significant as military preparedness. It is a world problem. It is a mining engineering problem. Don't let it die!

Jan 1, 1952

By A. B. Parsons

LECTURE, it appears, is a discourse that is supposed to be instructive. I am quite sure that you will derive no instruction from what I have to say. I will be satisfied if my remarks provoke thought along one or two mental paths that have not been traveled so fre¬quently as to be devoid of interest. I have no particular message apropos of professional engineers or professional engineering, and any conclusions that I may seem to reach will be purely tentative and incidental. Probably at times you have wondered, in a casual way at least, why so many people who are not, never have been, and never will be engineers, want to use the title. For example, I recently received a communication from a life insurance broker or salesman, whose chaste letterhead bore the legend "Estate Engineer." He was perfectly serious about it, as is also the expert accountant who assumes the imposing name of cost-analysis engineer. Dozens of equally amazing titles might be cited. Then there is that class of individuals who have been engineers, in the true sense of the word; who have gone into some other kind of occupation; but who cling tenaciously to the name engineer, usually prefixing some word or other which at once gives them away by telling what their work really is. For example, we have such pseudomorphs as the management engineer, and the sales engineer. It is quite evident that engineer is a word to conjure with. Evidently both the man who appro¬priates the designation without any justification and the ex-engineer who persists in calling himself an engineer even after he has abandoned engineer-

Jan 1, 1933

By James H. Bechtold

The yield strength of annealed tungsten was found to have a strain rate exponent 12 times as great as that of low carbon steel. The effects of temperature and strain rate could be correlated through the Zener-Hollomon parameter with a heat of activation associated with yielding of 32,000 cal per g-atom. This heat of activation is independent of strain although both the temperature and strain rate dependence of the yield strength vary with strain. MOST metals have mechanical properties that are relatively insensitive to strain rate, especially at temperatures below that at which creep is important. In iron and molybdenum," however, relatively large strain rate effects are observed in the temperature range where the rapid increase in yield strength occurs which leads to the ductile to brittle transition. In this temperature range Zener and Hollomon' have suggested that the effects of strain rate and temperature T on the yield strength could be correlated through a single parameter, P, in the following manner where Q is a heat of activation characteristic of the metal and associated with some unspecified relaxation process. They also observed that if the temperature is restricted to a relatively narrow range— below room temperature for steel—that the logarithm of the yield strength could be expressed as a linear function of the logarithm of P. From this relation the logarithm of stress should be a linear function of the logarithm of the strain rate at constant temperature: where r will be referred to herein as the strain rate exponent. At a constant strain rate the logarithm of stress should be a linear function of l/T, ay(e = C) ~ eT [4] where q = Qr [5] and is referred to herein as the temperature exponent. These equations have been found to relate the effects of temperature and strain rate on the yield strength of molybdenum in the temperature range wherein the ductile to brittle transition occurs, —75° to +150°C.2 Bechtold and Shewmon3 have shown recently that the ductile to brittle transition in annealed tungsten occurs in the temperature range +150° to +350°C. In this temperature range the yield strength in-

Jan 1, 1957

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 Laurence Delisle, Arron Finger

The alloys formed by the addition of nickel to iron by conventional metallurgical procedures show physical properties that differ widely from those of the individual metals. The effect of alloying on the mechanical properties is most pronounced in alloys containing between 15 and 25 per cent nickel. The tensile strength of an alloy containing, for example, 20 per cent nickel and 80 per cent iron (with 0.06 per cent carbon), in an annealed condition, is above 150,000 lb. per sq. in.$ owing to a martensitic type of transformation, as compared with about 50,000 lb. per sq. in. for pure iron in the same condition. The object of this work was to determine whether the same beneficial alloying effect coulcl be obtained in alloys of iron and nickel prepared by powder metallurgy technique. Procedure Bars and pellets for tension and compression tests, respectively, were made. Two groups of specimens were prepared: (I) by cold-pressing the powders and sintering; (2) by cold-pressing the powders, sintering, repressing and resintering. Raw Materials Nickel powder supplied by Metals Disintegrating Co., marked MD-151, was used. A typical analysis of this powder was as follows: sulphur, 0.040 per cent; copper, 0.18; iron, 0.23; manganese, 0.002; magnesium, o.oo15; lead, 0.035; tin> 0.025; silicon, 0.08; chromium, 0.008. Electrolytic iron powder supplied by Plastic Metals Inc. was used. A repre-sentative chemical analysis for impurities other than gases, supplied by the vendor, gave the following results: carbon, 0.005 per cent; manganese, 0.002; silicon, 0.003; phosphorus, 0.001; sulphur, 0.004; nickel, 0.008. The fractions from these powders passing a 325-mesh sieve were reduced in hydrogen at 600°C. for one hour, to clean the sur-faces of the particles. The reduced pow-ders, slightly caked, were ground in a mortar and screened again through a 325-mesh sieve. Mixing The proper proportions of the powders were mixed overnight on rolls, in glass jars fitted with iron-wire baffles to break aggregates of particles that might form. Pressing All specimens were compacted on hy-draulic presses. The pellets were com-pacted in a cylindrical die, 34-in. diameter. The ratio of thickness to the diameter of the pellets was maintained as nearly as possible at 0.9, as specified for standard short compression pieces. The tensile bars were made by compacting 30 grams of powder. Their shape is shown in Fig. I. The compacting pressures for the pellets and the tensile bars were:

Jan 1, 1946

By Arron Finger, Laurence Delisle

The alloys formed by the addition of nickel to iron by conventional metallurgical procedures show physical properties that differ widely from those of the individual metals. The effect of alloying on the mechanical properties is most pronounced in alloys containing between 15 and 25 per cent nickel. The tensile strength of an alloy containing, for example, 20 per cent nickel and 80 per cent iron (with 0.06 per cent carbon), in an annealed condition, is above 150,000 lb. per sq. in.$ owing to a martensitic type of transformation, as compared with about 50,000 lb. per sq. in. for pure iron in the same condition. The object of this work was to determine whether the same beneficial alloying effect coulcl be obtained in alloys of iron and nickel prepared by powder metallurgy technique. Procedure Bars and pellets for tension and compression tests, respectively, were made. Two groups of specimens were prepared: (I) by cold-pressing the powders and sintering; (2) by cold-pressing the powders, sintering, repressing and resintering. Raw Materials Nickel powder supplied by Metals Disintegrating Co., marked MD-151, was used. A typical analysis of this powder was as follows: sulphur, 0.040 per cent; copper, 0.18; iron, 0.23; manganese, 0.002; magnesium, o.oo15; lead, 0.035; tin> 0.025; silicon, 0.08; chromium, 0.008. Electrolytic iron powder supplied by Plastic Metals Inc. was used. A repre-sentative chemical analysis for impurities other than gases, supplied by the vendor, gave the following results: carbon, 0.005 per cent; manganese, 0.002; silicon, 0.003; phosphorus, 0.001; sulphur, 0.004; nickel, 0.008. The fractions from these powders passing a 325-mesh sieve were reduced in hydrogen at 600°C. for one hour, to clean the sur-faces of the particles. The reduced pow-ders, slightly caked, were ground in a mortar and screened again through a 325-mesh sieve. Mixing The proper proportions of the powders were mixed overnight on rolls, in glass jars fitted with iron-wire baffles to break aggregates of particles that might form. Pressing All specimens were compacted on hy-draulic presses. The pellets were com-pacted in a cylindrical die, 34-in. diameter. The ratio of thickness to the diameter of the pellets was maintained as nearly as possible at 0.9, as specified for standard short compression pieces. The tensile bars were made by compacting 30 grams of powder. Their shape is shown in Fig. I. The compacting pressures for the pellets and the tensile bars were:

Jan 1, 1946

By Sam Tour

SOME years ago, the writer described heat checks or thermal cracks that occur in die-casting dies.1 The life of dies was considered in relation to the casting temperature, the material used for the die, and the heat to be absorbed by the die per unit volume of casting made. The mech-anism of the action that results in thermal failure of dies was described. In the present paper the writer proposes to describe some additional observations in regard to heat checking, make one or two suggestions as to the method or methods for further attack of the problem, and give the results obtained on some work carried out along these lines.

Jan 1, 1934

By J. M. GLEDHILL

(Washington Meeting, May, 1905.) A Discussion of Mr. J. M. Gledhill's paper, read by title at the Lake Superior meeting, but presented first at the New Yolk meeting of the Iron and Steel Institute (October, 1904), and here published under a mutual agreement. Between the two Institutes. Discussion. MR. E: WINDSOR RICHARDS, Past-President, said that at a recent meeting of the Institution of Mechanical Engineers a paper was read on tool steel, and he called the attention of the members to the high-speed tool steel at the Bethlehem Works. They would have the pleasure of seeing those wonderful works and would see 60, 70, 80 and 100 tons oil lathe with half-a-dozen of these high-speed tools running. PROP. H. M. HOWE (Columbia University) said that they all looked upon these high-speed tool steels as of very great importance, particularly to the machine shop. One point occurred to hire : Had it really been shown that Swedish steel is necessary, or better than equally pure steel that is not Swedish; and is cemented steel really necessary, and is there any advantage in using that, rather than equally pure open-hearth steel'! It might be well if the author could indicate the kind of evidence on which lie bases his assertion that it is necessary to have cemented Swedish steel. Many were hoping for the development of high-speed steels from elements which exist in great quantities, such as silicon, manganese and chromium, rather than from rarer metals like molybdenum, vanadium and tungsten, the supply of which is likely to be soon exhausted. If the high-cutting speed was to last more than a generation, it. seemed to him that they would have to draw upon the common ele¬ments and not upon the rare ones. MR. Tom WESTGARTH (Middlesbrough) said he fully appreci¬ated what had been said about the advantages of using high-speed steel, because great benefit had been derived from the

Mar 1, 1905

By Paul Weir

FOR the first time in 1938, bituminous coal production for the week ending Nov. 19 surpassed that of the corresponding week in 1937, and indexes of industrial activity indicated the possibility that the remaining weeks of 1938 would run ahead of the corresponding weeks of the preceding year. But regardless of this year-end pickup, total production in 1938 was approximately 25 per cent less than in 1937. The estimate of 340 million tons for 1938 places the bituminous industry slightly above the production level of 1933 and approximately 10 per cent above the modem low of 1932. Anthracite production is not subject to the same extent as is bituminous coal to fluctuations arising out of the rate of industrial activity, hence the decline from 1937 has not been so great being approximately 14 per cent under 1937. The estimate for 1938 production is approximately 45 million tons, but this represents the lowest level reached in the last fifty years with the possible exception of several strike years.

Jan 1, 1939

By JO. E. SHERID

THE Dawson coal-mines are owned and operated by the Stag Canon Fuel Co., of which Dr. James Douglas is President and E. L. Carpenter general manager. The property is situated in Colfax county, N. M., and the openings now in operation are in townships 28 and 29 N. R. 20 E., and township 28 N. R. 21 E., shown in Fig. 1. The mines are part of the southern end of the Raton coal-field, which extends north into Colorado and embraces many coal-camps of the Trinidad section. II. GEOLOGY. Geologically, the coal-measures, commonly known as the Laranmie series of the Cretaceous system, have a thickness of about 800 ft. in the vicinity of Dawson. The coal makes an excellent coke, and, according to some authorities, its coking properties are clue to the action of intruded sheets and sills of igneous rock, the sheets occasionally thickening into masses resembling laccoliths, at such places making nearer approach to the coal and sometimes producing small areas of natural coke. There are but few dikes through¬out the entire southern portion of the field and little or no faulting along the dikes. In some parts of this great coal-field the intrusive sheets are far removed in the green shales below the coal-measures, and are so much altered as to be difficult of identification. There is but little disturbance of the strata through¬out the Raton coal-field in as far as it extends into New Mexico. There are two workable seams in the coal-measures, and two or three smaller coal-seams, ranging from 1 to 2.5 ft. in thick-

Jun 1, 1909

By AIME AIME

THE list of deaths during the year 1906 comprises the following names, the figures in parentheses indicating the year in which the persons named were elected to membership Members and Associates.-Arthur Vaughan Abbott (1882), William Anderson Akers (1889), R. Scott Allen (1905), George H. Arlett (1900), Thomas Septimus Austin (1883), Thomas T. Baker (1887), William Tittley Batchelor (1902), Charles Lowthian Bell (1897), Edgar Vallentine Bensusan (1892), George Lothrop Bradley (1874), Ernst Elmer Breisch (1896), Horace F. Brown (1895), James A. Burden (1876), Alexander B. Coxe (1880), George A. Crocker (1879), Albert W. Fiero (1886),

Jul 1, 1907

By Arthur S. Huey

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

Jan 1, 1932

By L. Weaver

THE Tennessee Copper Co.'s mines are in the southeast corner of the state of Tennessee, Polk Co., in the well-known Ducktown copper basin. Their new circular production shaft will eventually be the only ore hoisting shaft, and is located for handling ore from Boyd, Calloway, Mary, and Cherokee mines. A circular, rather than a rectangular, shaft was decided upon because: 1-The circular shaft section is stronger when lined with concrete. Reinforcing steel was not required, thus reducing lining cost by one- quarter. 2-Water sealing was desired; it was thought it could best be done with a concrete lining followed by pressure grouting to eliminate water seeps. 3-The shaft labor saving equipment could best be used in a large opening, so the round section was made for economy, sinking, mucking, concreting and water sealing. Less shaft steel is used than could have been possible with steel sets. There are no posts required; center beams and Tee plate assembly placed at 10 ft hold the 100 lb steel guide rails.

Jan 1, 1950

By William M. Bowron

THIRTY years ago, when I stood on the cliff of red fossil iron-ore, on Red mountain, Jefferson county, Ala., I asked what were the geological relations of this remarkable deposit. In reply I was told that it was a limestone colored and saturated by some unknown but wholly external influences, and that at a reasonable distance from the surface the color would disappear. I could find no satisfactory explanation either of the nature of this wonderful external permeating influence, or of the cause of such a ferrous impregnation selecting this one particular bed of limestone, to the exclusion of the higher and lower beds of the same material which are not even stained. I. THE PRESENT THEORY. Referring to this subject, Dana says:' "The clays, clayey sandstones and limestones of the Clinton epoch, through New York and the Appalachians, show that the mud-flats and sand-banks, and hence the shallow seas of the coast region, still continued. . . The beds of argillaceous iron-ore, which spread so widely through New York and some of the other States, south and west, could not have formed in an open sea, for clayey iron-deposits do not form under such circumstances. They are proof of extensive marshes, and, therefore, of land near the sea-level. The fragments of crinoids and shells found in these beds are evidence that they were, in part at least, salt-water marshes, and that the tides sometimes reached them." At first, this explanation seemed satisfactory, but the more I studied the ore the less satisfying the explanation became. 1. In the ore itself I found associated with the small particles of rounded matter (now consisting of iron oxide in which organic structure, if ever present, has become lost, though the

Nov 1, 1905