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BOSTON SECTION ALFRED C. LANE, Chairman, GEORGE A. PACKARD, Vice-chairman, E. E. BUGBEE, Sec'y-Treas., Mass. Inst. of Technology, Cambridge, Mass. R. L. AGASSIZ, FRED W. DENTON. Forty-sixth Meeting The forty-sixth meeting of the Boston section was held at the University Club on Monday evening, Jan. 28, 1918. Thirty-six members and guests were present, which is a record for this Section. After a good dinner, President Philip N. Moore, of the Institute, was introduced, and spoke of the many problems of the Institute. The topics covered were the progress and growth of the Institute during the administrative year, the efforts to stimulate the local sections and to bring them more in touch with the policies and problems of the parent body and, last but not least, of the constructive results and patriotic work of the Institute in the national service of the war. The other guest of the Section, Mr. Thomas Nelson Perkins, Counsel for the Priority Board, spoke most entertainingly of recent experiences in Russia, England and France. After considerable discussion during which Mr. Perkins most obligingly answered innumerable questions, the meeting adjourned at about 10 p. m.

Jan 7, 1918

By Larry D. Hartzog

PANELISTS Paul Chamberlin, Nerco Minerals Jim Gourdie, Goldfield Mining Corp. Roger Leonard, Cyprus Northumberland Mining Co. Eric Daniels, Tenneco Minerals John Dasher, Consulting Metallurgist Bob Shoemaker, San Francisco Mining Associates Larry Hartzog, Bechtel Civil and Minerals, Inc.

Jan 1, 1984

By B. H. Caudle, B. M. Hickman, I. H. Silberberg

Secondary recovery projects often are not started in oil reservoirs until dictated by rising GOR's or declining oil production. Such circumstances require a well dispersed injection pattern to prevent the oil bank from bypassing the production wells. Many times this purpose is served by using the five-spot or line-drive patterns, in which half of the wells are made injection wells. A regular injection pattern is proposed that is based on the same well spacing as the five-spot but in which only a third of the wells need be converted to injection wells. Fluid flow model studies on this proposed pattern show that production histories will be as good as those for a five-spot pattern at mobility ratios of three and above. The model data are presented in a form that may be used to predict recoveries from both homogeneous and stratified formations. Introduction The injection of fluid into a petroleum reservoir usually is prompted by an actual, or predicted, loss in the productivity of the reservoir. Often, an oil reservoir is produced by pressure depletion until high GOR's dictate a change in policy. Fluid injection also causes increased ultimate recovery, but this usually is of less importance to the operator than is the maintenance of the production rate. It is a fact that the ultimate recovery in any particular fluid injection project is relatively independent of the number and spacing of the injection wells as long as the reservoir voidage through the production wells is balanced by the total injection rate. However, the response of a production well is directly affected by the distance it lies from an injection well. In places where the well productivities are declining, the injection wells should be spaced as evenly as possible among the producing wells ("dispersed" injection pattern). More particularly, if the production response depends upon the formation (and subsequent production) of an oil bank, each production well should be surrounded by injection wells. Otherwise, the oil productivity will increase very little as the oil bank moves past the well.'.' An evenly spaced injection pattern has the best chance of generating an oil kick in the production wells. If reservoir voidage and injection rates are to be equal, the ratio of injection wells to production wells must be equal to the ratio of the average injectivity to the average productivity (in reservoir volumes). This ratio is in strumental in choosing the injection pattern. Table 1 shows the production well to injection well ratio for the dispersed injection patterns that have been described in the literature.'-' All of these patterns will have comparable recoveries and response times (for the same basic distance between wells). The choice of pattern there fore depends upon the relative injectivity and productivity of the wells and upon the type of drilling pattern employed. Another important factor may be the ability of the proposed production wells to make up the lost productivity from those wells converted to injectors. These factors become more pronounced at the higher oil viscosities (low gravity oils). All other things being equal, the probable ratio of single well injectivity to single well productivity will be equal to the water-oil mobility ratio of the proposed flood. Thus, high mobility ratios (due to low gravity oil) should call for fewer injection wells — as long as these injection wells are "dispersed" to obtain more even pro duction response for the remaining wells. Secondary re covery projects in oil reservoirs seldom, if ever, will have mobility ratios requiring more injection wells than production wells. Thus, only the last five of the patterns listed in Table 1 will be of significant interest in oil recovery. Almost every development drilling program calls for the wells to be drilled along equally spaced rows and

Jan 1, 1969

By Howard W. Jacky

At Weed Heights, Nev., precipitation plays a major role in the plant operation. Almost two-thirds of the present copper production is leach-precipitation plant copper. The entire plant complex processes about 135,000 tons of low grade copper ore per week. Of this tonnage, 49,000 tons of about 0.78% sulfide ore are treated in the concentrator. This is handled in the conventional manner of crushing, grinding, and concentration of the copper sulfide by flotation.

Jan 6, 1967

By D. C. Jones

THE term "coal-mine mechanization" is definable in several ways. In its general application it can mean the use of machines instead of manpower in each of the various mining activities necessary for the produc¬tion of coal-so that under this definition a mine that uses mechanical coal cutters could be classed as a mechanized mine. Common usage, however, insists that a mechanized mine is one in which machines are used for the entire process of mining or extraction and transportation of the coal. For the purpose of this paper, then, the second definition of "coal-mine mecha¬nization" will be used, and practices employed in mines where the greater part of the production is obtained through the use of mechanical loaders and conveyors will form the basis for this discussion. PHYSICAL CONTACT HAZARDS If we were to group all the hazards that accompany the use of mechanized equipment in a mine, the predominant class would be that which, for want of a better name, might be termed the "physical contact" hazards; that is, all the sources of danger that lead to accidents through physical contact of workmen with ma¬chines. A survey of accidents in a group of mechanized mines indicated that this class of hazards may be responsible for more than half the number of accidents in mechanized mining. For example, of 21 mining-machine accidents at one mine, 14 were of the physical contact type of 14 loading-machine accidents at the same mine, 8 were the result of physical contact. Certain of these hazards an controllable through the use of guards-¬a guard over the cutting-machine bits whet the machine is being trammed from place to place, or a chain or some similar locking device around the cutter chain, so that an accidental blow or push against the bit control will not cause the cutter chair to move. Other hazards, such as the possibility of. a loader operator having hi foot crushed by a crawler tread, or , brakeman being hit by a loader boon swung too far to one side while a car is being loaded, might be subject to control through the use of guard devices, but the reduction or elimination of all physical contact hazards by such methods doe: not appear feasible. Every accident of the physical contact type should be investigated to discover whether guards could have prevented it, but often the only way in which to combat these hazards will be through the awakened consciousness of each workman as to the danger that exists if he indulges in unsafe practices. A good approach to control of accident: in any mine is the establishment of a set o: safety rules or operating rules. The intent of such rules is to provide guides for the workmen to follow in the operation of equipment. Frequently the workmen have no regard for such rules, and observance is obtained only through compulsion or the part of management. An interesting development in connection with the formation of safety rules occurred during a training program for employees in the

Jan 1, 1946

By Robert Sisselman

Saving time and energy at Consolidation Coal Co.'s Rowland mine is realized by exploiting its coal deposits via three mining methods. Surface, auger and underground techniques are uniquely combined with specialized transport vehicles to coax the coal from seams unduly protected by topography and lithology. These factors account for what is believed to be the swiftest and most economical means of working the Beckley, W. Va., property.

Jan 1, 1970

By J. Lyndon Rosenblad

This chapter describes the development of a rocklike model material for use in tests with a rock-blocks model to investigate the failure mechanism of a discontinuum. In order to provide reliable results, the model material must be characteristic of natural rock and obey the laws of similitude. Initially, the development of such a material does not appear to be a difficult problem. Only when one undertakes such a task does he realize how little is actually known, and that there is considerable work yet to be done. A material that simulates rock in all of its physical properties probably will never be developed. There is now and probably always will be room for improvement. Improvement is needed not only in the component materials but also in the technique of preparation. The material developed and subsequently described in this chapter simulates rock in general and a schistose gneiss rock in particular. The material possesses many rocklike physical properties not found in previously used model materials. One of the most significant improvements of this material is that there is an increase of Young's modulus with an increase in confining pressure as determined by triaxial compression tests. A change in the usual procedure of material preparation was used to develop this material and is also described. MODEL MATERIALS USED IN THE PAST Intact Materials Numerous materials have been used by investigators in models in the past to simulate a wide range of prototype materials. Some of the materials used include cork, plastic, concrete, plaster of Paris, portland

Jan 1, 1972

MONTANA SECTION W. C. SIDERFIN, Chairman, OSCAR ROHN, Vice-Chairman, E. B. YOUNG, Secretary-Treasurer, 526, Hennesey Building, Butte, Mont. F. W. BACORN, C. D. DEMOND. The semi-annual meeting of the Montana Section was held at the Silver Bow Club, Butte, Montana, on Friday, Nov. 16, at 8 p. m.; this was a postponement of the regular October meeting because of conflict in date with the St. Louis meeting of the Institute. An informal dinner was served to 68 members and guests. After dinner, Chairman W. C. Siderfin called the meeting to order. The minutes of the annual meeting, of Feb. 2, 1917, and the special meeting of May 21, 1917, were read and approved. C. W. Goodale led the discussion with "Notes on the St. Louis Meeting." He was followed by J. H. Warner who spoke on " The Joplin and Miami Districts," and by J. L: Bruce, Alexander Leggatt, N. B. Braly, and E. B. Young, the latter speaking on the work of the War Minerals Committee; and on the Cosden Oil Refinery at West Tuba, Okla. R. H. Sales reviewed briefly the manganese situation. E. N. Norris presented a paper on "Fire Proofing of Mine Shafts by the Anaconda Copper Mining Co." This resulted in interesting discussion by C. L. Berrien, C. E. Nighman, N. B. Braly, W. B. Daly, B. H. Dunshee, and J. J. Carrigan. C. L. Berrien and C. E. Nighman presented their papers on "Fire Extinction by Hydraulic Filling." In view of the late hour, discussion was waived. The executive committee, by unanimous consent, decided to request written discussion of the above papers to be presented at the next meeting, in February. B. B. Thayer spoke interestingly on the work of the Naval Consulting Board, and referred to the arsenic situation. Spencer Miller, also a, member of the Naval Consulting Board, entertained the-meeting with a vivid description of the method of "Coaling Battleships at Sea." Robert Sticht of Tasmania, in a short talk, spoke feelingly of his relations with the United States. At a late hour adjournment ended a most successful and interesting meeting. E. B. YOUNG, Secretary.

Jan 1, 1918

By J. A. Thompson, M. A. Mayers

IN recent years, the problem of damage to coke-oven walls by expanding coal charges undergoing carbonization has engaged great attention on the part of research workers in this field, and has led to the development of many devices for estimating these pressures.1-14 Only in Russell's method11 and in the Koppers ovens7 are conditions quite similar to those in commercial ovens. Tests even in these ovens are empirical because no information has been published to permit an evaluation of "scale effects." Owing to the relatively large wall area in these test ovens, the average wall pressure determined may be lower than that existing in localized areas. This factor may be compensated for in part by the testing of coal charged into the test oven at a bulk density that is as high as the highest that is believed to exist in commercial ovens. Both of these lacks might be filled by the development of an adequate gauge for the direct measurement of wall pressure exerted by the charge in commercial coke ovens in normal operation. Previous attempts to elaborate such instruments7,15 have resulted in units which, because they had to be water-cooled, probably produced changes in the conditions of carbonization, and which had to be removed from the oven before carbonization was complete, to avoid their destruction. Late in 1941 the Coal Research Laboratory undertook to develop such a gauge, in which gas pressure was balanced against the charge pressure and which thus would not require water cooling, on a suggestion made in 1937 by one of the present authors and William B. Warren, a former member of the Laboratory staff. The gauge heads themselves were to be simple and cheap enough so that they might be discarded after each run if seriously damaged. This would permit them to be left in place throughout the carbonizing period, when they could be pushed out with the coke. The basis of the design, of which the latest exemplification is shown in Fig. I, was that as the internal gas pressure within a flexible metal envelope was increased, the flexible wall would move away from a stop when the gas pressure just overbalanced the charge pressure. If the stop were an insulated electrical contact, the point of balance could be indicated by the breaking of an electric circuit. It was anticipated that, while the instrument must operate at high temperature, the presence of a strongly reducing atmosphere throughout the carbonizing period would so reduce-the danger of scaling that mild steel could be used for the gauge. This expectation has been justified. Danger of attack on silica oven walls by the steel gauge body can be eliminated by cementing asbestos paper or an alundum or silica plate to the back of the gauge body. The gauge head itself has a relatively heavy mild-steel body, A, into which standard ¼ in. pipe B is screwed to conduct gas and electrical leads. The body is closed by a single bellows C. consisting of two annuli of 0.011-in. (0.28-mm.) cold-rolled shim-steel spot-welded together at their outside edges. The lower one is

Jan 1, 1944

By W. M. Gray

The determination of the state of stress existing at a point in any solid body requires the determination of the six components of the stress tensor relative to a convenient set of axes. One general method of doing this in rock is to make strain or deformation measurements associated with local relief of stress in a number of boreholes penetrating a limited volume in the vicinity of the point at which the stress is to be determined. The stress is assumed to be constant throughout this volume. Leeman1 has described a number of the instruments that have been developed for making deformation or strain measurements in boreholes. Panek2 has described the application of statistical methods to the determination of the average components of ground stress from sets of measurements made in boreholes by means of deformation meters of the type developed by the U.S. Bureau of Mines. In this paper attention is given initially to the strain cell developed for use on the flattened ends of boreholes by the Council for Scientific and Industrial Research (CSIR) , South Africa. The equations required for evaluating the average components of ground stress from measurements made by means of the CSIR strain cell are derived. These equations are similar in form to those applying to measurements made by the borehole deformation meter developed by the U.S. Bureau of Mines. The results of an investigation of the properties of the equations are described. These results are important in the practical use of both the instruments mentioned above and any instrument based on similar principles.

Jan 1, 1968

By Nicasio del Castillo

INTRODUCTION The tax structure of foreign mining investment into the United States has a significant impact on the financing and the profitability of the operation. For these reasons, it is critical for the foreign investor to develop and implement a well planned tax strategy that will enable its venture to: (1) reduce its U.S. income tax liability (2) lower U.S. withholding taxes when funds are transferred from the United States, and (3) decrease or defer home country taxation on its U.S. earnings ALTERNATIVE FORMS OF INVESTMENT A threshold business and tax consideration is the form in which the investment is to be made. The most common alternatives include: forming or acquiring a U.S. mining corporation, directly establishing a branch mining operation, or entering into a joint venture or partnership with a U.S. mining company. U.S. Corporations The most common structure through which foreign mining companies engage in business in the United States is to form a U.S. mining corporation. Forming a U.S. Corporation. If the investor decides to establish a new U.S. corporation the organization is relatively simple. No distinctions are made in the United States between "public" and "private" forms of incorporation. Minimum share capital is not usually required and share capital may consist of shares with no par value. Since corporate law is the responsibility of the individual states, the foreign investor must choose a state in which to incorporate. If appreciated mining property is transferred to a corporation solely in exchange for stock or securities in that corporation, and the transferors have control of the corporation (defined as at least 80 percent of all voting shares and at least 80 percent of all other shares) immediately after the exchange, no gain or loss will be recognized. However, if the transferors receive cash or other mining properties in addition to stock, any resulting gain may, in certain situations, be taxed to the extent of the cash and the fair market value of other property received. Acquiring an Existing U.S. Corporation. Acquiring an existing U.S. mining corporation is not as straight-forward as forming a corporation. This alternative may be accomplished through either a stock or an asset acquisition. Generally, with a stock acquisition the purchaser inherits all of the business and tax attributes of the former mining corporation. If the investor is able to acquire mining assets, however, the purchaser will usually be able to avoid any unknown or hidden liabilities that could be attached to an existing corporation. Another principal advantage in acquiring assets is that the purchase price may be directly allocated to the acquired mines or other mineral-related assets with the result that the assets' depreciable base may be increased. Assuming the domestic seller and the foreign purchaser can agree, it is generally advisable to allocate the purchase price in the sales agreement to specific individual assets. From the foreign investor's standpoint, it is preferable to allocate the purchase price to depreciable assets such as buildings and equipment versus an allocation to mineral land holdings or intangibles such as goodwill, which are generally not depreciable. It is not uncommon, however, for a seller mining company being acquired to insist for tax reasons that the investor purchase shares rather than assets. If the foreign

Jan 1, 1985

By K. V. Lindell

THE 70-mile serpentine belt of eastern Quebec, producing 70 pct of the world's chrysotile, has 11 operating mines, two of which are underground, eight are open-pit, and one is both open-pit and underground. The combined operation, the Jeffrey mine, of the Canadian Johns-Manville Co., Ltd. is the largest producer in the group. Haulage All four of the separate operations falling under transportation at the Johns-Manville Jeffery Mine at Asbestos, P. Q., is handled by the company owned Asbestos and Danville Railway. A variety of equipment is operated over the 25 miles standard gage railway. Included in the scope of transportation are: 1-Hauling mill rock to the mill. 2-Hauling stripping and waste rock to the waste dump. 3-Hauling mill tailings to the tailings dump. 4-Hauling supplies from, and finished products to Danville. Main line tracks are permanent, but those within the pit and on the dumps have to be relocated constantly to follow the mining face and dump edges. Tracks within rock areas in the mine are laid on steel ties and can be moved by a bulldozer. Standard mechanical track shifters move tracks in dirt areas in the mine and on the dumps. Train-movements, both within the mine and over the out-lying tracks are controlled by a dispatcher located at the southwest rim of the pit. Steam locomotives haul all stripping, waste rock, and ore from the mine to the gathering yard at the northwest rim of the pit. Normally, two trains per operating shovel are used, with adjustment for optimum loading. In the event of shovel loading on the bottom level or in good stripping, service may be increased to three or four trains per shovel. From the gathering yard a 100 ton diesel-electric locomotive hauls the mill rock to the mill slips, a distance of about three miles. Electric or steam locomotives haul the waste rock and stripping to the waste dump located about two and one-half miles from the mine. Stripping cars are sprayed with a chloride solution and "gravelled" to prevent wet stripping from freezing in the cars during the cold months. Cars pass under a shaking screen which distributes an even

Jan 1, 1952

By H. M. Roche

IN the first section of- this article, published- Feb. 4, the author reviewed the his¬tory of iron ore mining in New Jersey, listed the reserves and possible markets of this ore, and discussed the role of Lake Superior and foreign ores in domestic steel production. This concluding section of the article emphasizes the metal¬lurgical value, future markets and mining coats of Jersey ores. Mr. Roche's thesis is that industry can profit both metallurgically and econom¬ically through a greater use of Jersey ores --that these orebodies are as yet prac¬tically unexploited, and con¬stitute a valuable national re¬serve fully worthy of careful consideration by Mid-West¬ern steel makers.

Jan 1, 1937

Joseph Esrey Johnson, Jr., had already achieved rare distinction as an able metallurgist, clear thinker, brilliant author, and wise consulting engineer to bankers and operators; he had achieved the essentials of a great career when death cut short his activities on Apr. 4, 1919, in the forty-ninth year of his age. He belonged to a family of iron blast-furnace men and mine managers. His father, Major J. E. Johnson, after serving with distinction in the Army of the North, identified himself with the iron mines and blast furnace at Longdale, Va., with which he was connected during almost his entire business life. It is significant that, during those troublous times of reconstruction in the South, he enjoyed always the affection and respect of his neighbors and associates alike. From him his son obtained not only a thorough training in blast-furnace practice and iron mining, but great personal courage and force of character. His mother, who survives both her husband and sons, possesses rare intellectuality, humor and a tenderness and human sympathy which those who were privileged to know well J. E. Johnson, Jr., recognized beneath his exterior of aggressiveness and will power. In a recently published analysis of the qualities which characterize the world's great men, three traits stand out preeminently; viz., independence, courage, and intellectuality. Each of these characteristics J. E. Johnson, Jr., possessed in extraordinary degree. His early education was obtained under a private tutor at Longdale, and this circumstance probably enhanced , a natural tendency to independence of character and individuality which, however, under the control of his

Jan 5, 1919

By J. R. Long, E. L. Anderson, R. S. Dean, F. S. Wartman

TITANIUM has been estimated to comprise about 0.65 per cent of the earth's crust and ranks fourth in abundance among the metallic elements suitable for engineering uses. In spite of this, applications of titanium for structural purposes have not as yet been developed. Its commercial exploitation has been largely confined to the chemical industries and the production of paints and pigments; no doubt because of the difficulties that lie in the way of preparing the pure ductile metal. Published reports, however, indicate that ductile titanium can be prepared and possesses some unique properties. This, together with the occurrence in this country of several important titaniferous deposits, has led the Bureau of Mines to investigate processes for the production of metallic titanium, 'methods required for its fabrication, and the properties that may be produced in this interesting metal. METHODS OF PREPARING METALLIC TITANIUM Many early investigators claimed to have isolated metallic titanium; but in the light of present knowledge, it seems that they really had produced various mixtures of carbides and nitrides that have a metallic appearance but are brittle, hard, and unworkable. The first metallic titanium pure enough to be malleable when cold was produced by Hunter1 in the early part of the twentieth century. Kroll,2 van Arkel,3 and Fast,4 subsequently confirmed the facts that pure titanium is a ductile metal and that small amounts of impurities were responsible for previous reports of brittleness. When heated, titanium reacts chemically with various gases, such as hydrogen, oxygen and nitrogen; if the volume of gas thus absorbed is too great, the metal becomes brittle and unworkable. The principal difficulty in making ductile titanium is prevention of such contamination, and the success of a given process may be judged by the completeness with which it solves this difficulty in a practical manner. Of the gases mentioned, hydrogen is the least objectionable, since its absorption by the metal is completely reversible and, although dimensional changes occur and absorption of hydrogen embrittles the metal, the gas may be removed readily by heating in a high vacuum for a short time. On the other hand, the absorption of oxygen or nitrogen results in the formation of permanent 'solid solutions of the oxide and nitride, which cannot be decomposed by the strongest reducing agents2 with sufficient completeness to restore the inherent ductility of the metal. Because of

Jan 1, 1946

By Paul I. Eimon, Byron R. Berger

INTRODUCTION Epithermal silver-gold deposits form at low to moderate temperatures in near-surface environments. These deposits are found in all rock types, but historically, the most important deposits occur as veins in volcanic rocks (e.g., Creede, Colorado; Pachuca, Mexico) and as replacements in sedimentary sequences (e.g., Mercur, Utah; Carlin, Nevada). Increases in the open-market prices for silver and gold in the last few years have resulted in renewed interest in precious metals and the economic viability of large-tonnage low-grade deposits. These bulk-mineable deposits form as replacements in permeable horizons or as stockworks in the up- per parts of otherwise bonanza-type hydrothermal systems and newly recognized systems that erupted onto the surface as hot springs, fumaroles, or geysers. Large tonnage low-grade de- posits were an unconventional resource prior to price increases; however, now they constitute one of the main sources of precious metals in the United States and the importance is growing worldwide. This paper presents conceptual geologic- geochemical models of epithermal precious-metal deposits derived from studies of productive deposits throughout the world. Much of the data presented is not new. However, the interpretation of the data in terms of current concepts of hydrothermal processes is new. This paper deals with idealized and general ore-forming mechanisms, and no attempt is made either to explain the origin of the different chemistries of ore- forming fluids or to examine all of the variations in specific deposits due to local structural controls and host-rock compositions.

Jan 1, 1983

By L. O. Bacon, D. O. Wyble

THERE has been considerable speculation among mining geologists and mining men in general as to the relative merits of gravity methods in iron-ore exploration. Most of the investigations which have been carried out in recent years have been done by mining companies, and few if any of the results have been published. Three gravity surveys have been made in the Iron River-Crystal Falls area,1,2 one by the U. S. Bureau of Mines, with inconclusive results, and the other two by Radar Exploration Co. for the Cleveland-Cliffs and the M. A. Hanna companies, with results not known to the writers. Both the last-mentioned surveys were detailed investigations, the stations being spaced as close as 10 ft along traverses,1 and were made to determine the feasibility of locating iron ore by gravitational methods. Because of the presence of a large body of ore already extensively drilled, Dr. Harold L. James of the U. S. Geological Survey, Iron River, Mich., suggested that a further test of gravitational methods of exploration be made in the Round Lake area of Iron County, see Figs. 1 and 2. This survey indicated a considerable regional gradient and led to a study of the surrounding gravity field and its relation to the major structural features of the syncline within which the iron formation lies. The southwestern part of Iron County presents a series of hills and hollows elongated in a roughly north-south direction. The bedrock topography is of pre-glacial origin. Relief is moderate; a maximum elevation difference of approximately 350 ft was observed during the survey. Major drainage is dendritic with the larger streams: the Brule to the south, the Paint to the north, and the Iron in the central part. Hills are thickly grown with hardwoods, and lowland areas, not under cultivation, are usually covered by second-growth softwoods. The area covered in this paper includes the southern half of Iron County, Mich., with a deep synclinal basin occupying the central part of the area, and the southeast corner of Gogebic County, immediately to the west of Iron County. The upper Huronian iron formation, slates, and graywackes which form the synclinal basin rest upon a greenstone basement. The basin has not been completely outlined by exposures, drill records or other means, as outcrops are scarce and the thick mantle of glacial drift makes geological investigations extremely difficult. Glacial drift varies in depth up to 300 ft or more. The drift is usually thickest under the hills and is thinnest in the depressions and along drainage courses where most of the bedrock exposures occur. The area over which gravity investigations were made is almost entirely covered by glacial material. Bedrock of the basin consists of a complexly folded series of iron formation, slates, and graywackes. One of the series of slates has a high magnetic susceptibility due to the fine-grained magnetite it contains. This formation can be detected readily by magnetic methods and provides a marker horizon which can be easily followed. The magnetic slates are stratigraphically above the iron formation, and much of the geological interpretation of the area is based upon the magneticc anomalies they produce.

Jan 1, 1952

For many years the occurrence of gold in the Coeur d'A1ène region had been rumored among the pioneers of the Northwest. It is stated that as early as 1853 gold was discovered in this district by Donelson, of the Stevens expedition, but the hostility of the Indians prevented prospecting. In 1858, when Lieutenant John Mullan surveyed the military road across the Bitter hot mountains, the members of his expedition, most of whom had mined in California, noticed sundry outcrops of good-looking quartz, and some of them actually found gold, as is recorded in a letter that Mullan wrote, from Washington, in 1884. The first successful prospector in the Coeur d' Alène was Tom Irwin, who worked a quartz vein on the Mullan road in the spring of 1879. Two years later he met A. J. Prichard, who was engaged in the lumber business; he told him what he thought of the chances of placer mining in the upper reaches of the Coeur d7AlBne river. This was in 1881. Prichard became keenly interested, and himself found gold on several creeks, one of which is now known by his name, at a place close to the site of the town of Murray.* In 1883 Prichard located a number of claims, and shortly afterward he wrote a letter to the members of a Liberal League to which he belonged, inviting them to "secure the lion's share" of the mineral wealth he had uncovered. His letters caused a stampede from Montana and Colorado, and from South Dakota also, to the Coeur d'Alène gold belt in the summer of 1883. A town, named Eagle City, was surveyed; in 1884 lots sold at prices ranging from $200 to $2000. The buildings were made of logs and shingles. Shoveling of the snow in' front left s

Jan 1, 1932

By Ernest R. Lilley

While American scientific literature contains much information upon geologic conditions controlling the production of oil in Rumania, copper in Chile, and other fuel and metallic resources in many foreign countries, it is singularly lacking in data about the nonmetallics outside of the United States. Thus, though the United States is the outstanding market for European high-quality refined kaolin, and for the chinaware, porcelain, and other products of the European ceramics industries, American literature contains only the briefest references to the deposits from which the raw kaolin utilized is obtained. To the writer, to whom has come in the past year the opportunity of visiting a number of these deposits personally, they have proved of extreme interest both commercially and geologically. It is the latter phase that is discussed in this paper. The older and now largely crystalline rock areas of France, Germany, and other parts of western Europe contain numerous pegmatite dikes of which the upper portions have been subjected to surface weathering and kaolinization in much the same way as those of the eastern portion of the United States. Like the latter, the European pegmatite kaolins have long been known for their freedom from iron and other impurities offensive to the china and porcelain manufacturer. Unfortunately, they are also, like the American deposits, individually of small size and noted for their high costs of production. Deposits of sedimentary clay similar in many respects to the high-quality sedimentary kaolins of Georgia and South Carolina are known and worked, notably in southern Germany and in the Newton Abbott district of Devon and Dorset in England. In general, their relationship to the parent rock from which they were derived is more evident than in the United States and the individual deposits are of smaller areal extent and less regular in outline. While these deposits are of considerable economic importance they did not, because of their similarity to deposits in America, attract and hold the interest of the writer to the extent that several other types of deposits did. It is to the latter, which are so different from the kaolin

Jan 1, 1932

By Frank Riddle

THE life of thermocouples is governed, to a large extent, by the protection they receive when in use; particularly when the temperatures being measured are high and the products of combustion are reducing in character. Several types of protection tubes are being used for this work; they are made of ordinary and aluminous porcelain, fused quartz, carborundum, fused alumina, fireclay, and some kinds of metal. All of them may render good service under certain conditions but they must be used for the purpose for which they are intended. For example, fused-quartz tubes are very good when excessive changes in temperature occur, but under certain conditions they will crystallize and lose their strength. Porcelain is used in several ways in connection with the use of thermocouples: for insulating the two wires of the couple and to. prevent short circuits; for protecting the entire couple in a refractory gas-tight tube, which is ordinarily fastened to and is considered part of a properly equipped thermocouple; and for protecting the complete thermocouple from the possibility of physical injury and to support it. This tube is made porous and strong and is ordinarily built right into the wall or crown of the furnace, as the case may be. The insulating tubes must be small and sufficiently refractory to withstand the temperatures at which they are to be used. The length of the tubes, porosity of the material from which they are made, etc. does not particularly matter. The tubes are sometimes made with two or even four holes, the latter being used where it is desirable to have two couples as close together as possible for calibration work. The thermocouple protection tube must be of proper size to permit the thermoelements and insulating tubes to be inserted or taken out easily. It must be porous enough to withstand sudden changes in temperature and yet gas-tight, as well as refractory enough to withstand the furnace temperature, even if the tube protrudes into the furnace in a horizontal position without support for a reasonable distance. If the

Jan 9, 1919