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By J. W. Galpin, V. L. Minear, F. C. Sturges, B. H. Mott, R. H. Allen, W. W. Weigel, Wm. D. Owsley, R. E. Moeller

By definition the word "grout" means a thin mortar, or a kind of plaster or ce¬ment, and "grouting" means to fill up or finish with grout. The words "cement," "plaster" and "mortar" mean a substance that is used in a soft state which subsequently hardens. Thus, grouting is the filling of void space with a substance that hardens. Construction cements are the most common substances used, either by themselves or in mixtures, but the term grouting is applied quite correctly when other substances such as plastics and certain chemicals are used. Also, the use of the term grouting to cover the filling of voids with materials that do not actually become hard, such as the-flotation tailings used in grouting in the southeast Missouri lead district, should be considered correct, as some stiffening does take place and, anyway, it is a better descriptive term than any substitute. Engineers are interested in grouting because some of the materials with which they must work contain voids, and certain conditions can be improved if these voids can be filled with something solid and permanent. Grouting is done to accomplish several purposes: I. To stop the passage of fluids and gases, 2. To cement materials together to make them stronger, and 3. To prevent consolidation of materials by filling void space with something solid as a replacement for the air and water that could be forced out under load. The construction industry uses grouting extensively for all three purposes. Grouting is used to stop water percolation under and around dams. It is used to control water flow in tunnel driving and in shaft sinking. It is used to improve foundation conditions under civil engineering structures by permanently filling void space and thereby reducing settlement, or by cementing broken rock together and increasing its supporting strength. The oil and gas industry does a lot of grouting, primarily to stop the passage of gases and fluids. The search for oil at increasingly greater depths has meant greater investment per well, and the oil industry has spent large sums on development of improved drilling methods. This

Jan 1, 1948

By Strathmore R. B. Cooke, Thomas E. Ban

MUCH experimental work has been performed on the mechanism of agglomeration and pelletizing of moist ore and concentrates and on the process of firing agglomerates, but except for the work of Tigerschiöld and Ilmoni1 much of the published information is empirical, and the literature contains no information concerning the structure of fired pellets. Results of a preliminary study of the microstructures occurring in pellets produced both in the laboratory and on a pilot-plant scale are presented in this paper. Most of the results were obtained from pellets prepared from Mesabi magnetic taconite, but through the courtesy of the staffs of the Minnesota Mines Experiment Station and the Bethlehem Steel Co., fired pellets produced from limonite and hematite ores and from Lebanon magnetite have also been examined. The work has been restricted almost entirely to pellets produced without additives, the exceptions being those in which coal was. added to the filter cake before rolling. Schwartz has described the microstructures occurring in ore sinters produced under reducing conditions.2 Many of the structures and constituents he describes are common to fired pellets, but the constituents normally occur in markedly different proportions. His statement that "in all satisfactory sinter the amount of hematite is small, perhaps not over 2 or 3 per cent" is inapplicable to pellets produced by pilot plant operation or by any process in which air is not deliberately excluded. Pilot plant pellets contain over 90 pct by weight of hematite, and those produced in the smaller furnaces of the Minnesota Mines Experiment Station contain more than 80 pct of that constituent. Preparation of Specimens It is difficult to examine unfired pellets microscopically because of their insufficient coherency to withstand sectioning and polishing. Fired pellets sometimes lack coherency and frequently contain holes which are troublesome during polishing. Impregnation of both air-dried and fired pellets is readily accomplished by the use of methyl methacrylate monomer.3 The dry pellets are covered in a test tube with excess monomer, to which a small amount of accelerator has been added. When the test tube is placed in a cooling bath and evacuated with an aspirator, most of the entrapped air is removed, and disruption of weak pellets by boiling of the monomer is reduced to a minimum. Polymerization is then effected by immersion of the test tube in a water-bath at about 45°C, this temperature being held for 4 or 5 days. The test tube may then be broken away from the solidified mass and the pellets sectioned by a carborundum wheel or a diamond saw. Where time is important, impregnation is carried out at a higher temperature by Meyer's method.4 Air-dried pellets must be impregnated with especial care; otherwise swelling occurs and the solids are displaced. It is more important to be certain that the monomer forms a reasonably complete network throughout the specimen than that all entrained air is removed, and for this reason the vacuum technique may be omitted. Impregnated agglomerated products and pellets are extremely coherent, section well, and may be polished either by hand or by machine. Hand polishing is not satisfactory for the examination of conditions existing at the boundaries of grains, and for this machine polishing must be used. The Graton-Vanderwilt machine gives excellent results, provided that pressure on the specimen is considerably in excess of that recommended by the manufacturer. Mineralogy of Fired Pellets Only two opaque iron minerals, magnetite and hematite, have been recognized in pellets. The complete identity of these artificial minerals with their corresponding natural counterparts is shown by their mineralographic characteristics and their X-ray structures. Wüstite has not been found. Slag is the most common transparent constituent of fired pellets. Occasionally conditions have been appropriate for the crystallization of fayalite from the slag, and at other times another crystalline sil-

Jan 1, 1952

By E. F. Kingsbury

ONE of the well-known and important uses of the noble or precious metals has been for electrical contacts. In fact, the elements of this group, comprising gold, silver and. the six platinum metals, have been called "noble" because of their ability to resist heat and corrosion, properties which. were early found to be of importance in good contacts. Of these, platinum and its iridium alloys, palladium, and silver, have been extensively used. In recent years the electrical industry has been responsible for about one-eighth of the total consumption of the platinum metals in the United States. Information is not available as to what part of this one-eighth has been used for contacts but it is certainly an important one. SUBSTITUTES FOR PLATINUM During the past 20 years a considerable number of contact alloys have been proposed in the patent literature largely with the aim of more or less replacing platinum by gold or silver, and some of these alloys are finding increasingly widespread application as the reliability of their performance becomes established. From even the partial data at hand it appears that this substitution by the less precious metals has replaced at least one-half of the amount of platinum that the entire electrical industry would otherwise be consuming at the present time. While the subject is of considerable interest to the metallurgist it is even more so to the electrical engineer and it is surprising that the literature records no systematic and' comprehensive investigation along these lines. Practically all the scattered work on noble metal contacts has centered around platinum as a standard and has had two more or less distinct aims. One of these has been the replacement of platinum by cheaper materials, and the other, the development of materials of superior electrical performance. The merit, of a contact metal has been assumed to be dependent on its infusibility, and since the more precious metals have the higher melting points there has naturally been an association of the two qualities in the sense that the more precious were

Jan 1, 1928

By Percy Barbour

The town of Goldfield, Nevada, with the exception of six stone buildings, was burned to the ground to-day. One man is dead from causes attributed to the fire. A woman is missing and is believed to have perished and several persons were treated for burns as the result of the conflagration believed to have been of incendiary origin which started in the old Tenderloin District. The water supply was not sufficient and dynamite only scattered the frame structures and added kindling to the flames which were fanned by a forty-mile wind. Newspaper Dispatch, July 6. No former Goldfield resident could read that dispatch with unmixed feelings. About two o'clock one morning the crowded train from San Francisco landed me in Goldfield no more hours late than it habitually was. The desert air was clear and crisp and bracing but the pandemonium of cab and bus drivers did not drown out the sounds of music and merriment which floated from the blaze of light which was Goldfield about three-quarters of a mile from the station. As I stood in the ferry house, at the foot of Market Street, awaiting the Oakland Ferry, an old friend of mine, down to see who was departing for the greatest boom town of this generation, informed me that if I had made no reservation for quarters in Goldfield, I would be unable to obtain any, even chairs in the hotel lobbies were renting for $4 per night, and volun-teered the use of his room there for my convenience until his return. He described the house and location, which I identified without difficulty, but found no one to direct me to the room. I peered through a glass door into a room which seemed to be unoccupied and timorously entered and turned on the electric light., I found mail on the dresser addressed to my friend,

Jan 8, 1923

By Samuel Shallcross

THE principal function of the Bell limestone mine, of the American Lime & Stone Co., at Bellefonte, Pa., is to supply raw material to the company's modern rotary kiln plant at Bellefonte. Because mining costs are naturally higher than many open quarries with more favorably lying strata, it cannot compete, except to a limited extent, in the markets for road material and fluxing stone. In the broad sense, mining does have an advantage over the average open quarry when the end products are designed for and controlled by process and final inspection for the exacting demands of the industrial and chemical markets. Approximately 80 per cent of the output of the Bell mine is sold in the industrial and chemical markets. And as higher standards are set each year for construction and agricultural work, the remainder of the mine output goes to these two classes. Mining produces more fines than open quarries, and these fines are difficult to market; on the other hand, owing to absence of contaminating clay and impure rock, a greater percentage of the output of a mine is marketable. Because of the great production of fines, rotary kilns for lime burning are necessary when the stone must be mined. In 1921 the American Lime & Stone Co. operated 19 quarries and 72 lime shaft kilns spread over an area of 40 miles between Bellefonte and Altoona, Pa. At that time the line-production capacity of the 72 kilns amounted to approximately 700 tons per day. After 15 years the company operates three rotary kilns and six shaft kilns, with a combined output of approximately 500 tons of lime per day, concentrated in its single Bellefonte plant (Fig. 1). Its only stone-producing plants are now the limestone mine at Bellefonte and a construction-stone open quarry at Union Furnace, near Tyrone, Pennsylvania.

Jan 1, 1936

[Furnaces (see also Blast jurnaces) :-(Continued.) McGill, Nev., LI, 765. roasting: XLIX, 184, 188. Anaconda, Mont., XXXVII, 462, XLIX, 676. concrete hearths for, XLVI, 419. Crouse, XLVI, 413. gas, XXXVIII, 163. Heberlein, XXXVII, 634.]

Jan 1, 1918

The early history of coal in West Virginia is all included with that of Virginia in the few records available but for present-day readers it is much more convenient that the account of this area prior to the Civil War be grouped with that since then. West Virginia shares with Maryland in the first record of coal noted in the Appalachian fields. This was along the upper Potomac River, in the fall of 1736, and the data about it are given under Maryland, as most' of the development of the area was in that state. The next record of coal was left by John Peter Salley in his account of the expedition he made with Howard and others in 1742. (See p. 17.) The next reference found is that of Dr. Thomas Walker, in 1750, when he passed through the Pocahontas coal field. This has been described on page 18. Six years later, in March 1756, Capt. William Preston, who was with Major Lewis in his expedition down Big Sandy River, wrote in his journal: "Tuesday 2.... Moved down the branch and- came to the main creek where we camped. Put on half rations. Came into the Cole land; crossed the river 8 times."1 The party crossed from the head of Clinch River to Horse Pen Creek, then to Jacob's Fork and down it to Dry Fork of Tug River; the coal was seen in what is now McDowell County. The early settlers must have known of the presence of the great Pittsburgh bed in the northern part of the state, both along the Monongahela River and elsewhere, because the outcrops could easily be seen along streams in many. places. The report of the Commissioners for Adjusting Claims to Unpatented Lands, made in 1789, contains several references to coal in the names of streams, made years earlier. The earliest is one for 1,000 acres to James Walker, in Monongalia County, "adjoining his settlement on a branch of the right hand fork of Pappaw known by the name of the Stone Cole Lick made in the year 1773."2 Another of 400 acres in the same locality was settled upon in 1777.2 A third spoke of a tract "on the left hand fork of Stone Cole about three miles from the mouth," in 1783.1 Monongalia County then covered all of the northern

Jan 1, 1942

By J. E. Johnson

THE production of metal-working tools has been revolutionized within the last 18 years, since the invention by Taylor and White of a process of heat-treating steel tools, which resulted in increasing their cutting capacity several fold over what it had been before. This was an exceedingly important invention, although it consisted principally, in establishing this fact overheating when it accidentally, occurred in the ordinary:-process of forging, spoiled the steel, but if carried very much farther or to-a point that would have been considered absolutely ruinous to the steel under the old ideas, it resulted in imparting a cutting power several times as: high as had ever been obtainable before. The quality that gives the steel this power eventually received the name of "red hardness." This name originated in the fact that tools possessing this property retain their resistance to deformation even when subjected to, such severe cutting stresses that the metal just back of the point is heated, under certain conditions, to a visible red. It is interesting in this connection to note that the edge of the tool itself does not become red because it is continually cooled by the fresh metal into which it is forced. The result of Taylor and White's invention was an intensive study, of tool steels all over the world and, although there was-great diversity of analysis in the high-speed steels of the early days, these steels today generally have an approximately similar composition, the principal constituents being froth 15 to 20 per cent. of tungsten, from 4 to 6 percent. of chromium, from 1 to 2 per cent. of vanadium, and from 0.50 to 1 per cent. of carbon. It is probably safe to say that standard brands of such high-speed steels will do from five to ten times as much work in a given time as the carbon steels, and even the Musket steels, which were the sole dependence up to the beginning of this century, when the Taylor-White process was discovered. With the increasing cost of labor, it is not surprising that these steels have driven froth the market, for all but limited purposes, the older types of steel.

Jan 2, 1919

By Francis M. Rice

Before the world-wide depression, the primary purpose of most blast-furnace operators was to produce a maximum tonnage of pig iron per day for each furnace in blast. Some attention was paid to the conservation of labor and raw materials, but the idea was well established that low-cost pig iron was attainable only when each furnace was producing a high tonnage. After the depression had set in, the picture changed considerably. Each blast-furnace operator was forced to run his plant in a manner that best fitted the economical set-up of his company. A great deal of thought was expended on the different methods of operation, always with the idea of making each product in a way that would best serve his company financially. Because of this abnormal condition, the blast-furnace man was compelled to indulge in various practices of which many had been believed to be next to impossible up to that time. The ultimate purpose of these innovations was either one or a combination of the following: 1. To produce only enough pig iron for immediate consumption at a minimum cost. 2. To produce gas for boiler or mill use to supplant some higher priced fuel. 3. To consume the coke produced at the coke plant, which was often viewed as a byproduct. 4. To protect the cash position of the company. These conditions were met by diverse methods, some of which were: 1. Slow or decreased wind. In some instances the blast blown was held as low as 25 per cent of the normal volume. 2. Intermittent operation, in which the furnaces were shut down or "fanned" at frequent intervals.

Jan 1, 1935

By Francis M. Rice

Before the world-wide depression, the primary purpose of most blast-furnace operators was to produce a maximum tonnage of pig iron per day for each furnace in blast. Some attention was paid to the conservation of labor and raw materials, but the idea was well established that low-cost pig iron was attainable only when each furnace was producing a high tonnage. After the depression had set in, the picture changed considerably. Each blast-furnace operator was forced to run his plant in a manner that best fitted the economical set-up of his company. A great deal of thought was expended on the different methods of operation, always with the idea of making each product in a way that would best serve his company financially. Because of this abnormal condition, the blast-furnace man was compelled to indulge in various practices of which many had been believed to be next to impossible up to that time. The ultimate purpose of these innovations was either one or a combination of the following: 1. To produce only enough pig iron for immediate consumption at a minimum cost. 2. To produce gas for boiler or mill use to supplant some higher priced fuel. 3. To consume the coke produced at the coke plant, which was often viewed as a byproduct. 4. To protect the cash position of the company. These conditions were met by diverse methods, some of which were: 1. Slow or decreased wind. In some instances the blast blown was held as low as 25 per cent of the normal volume. 2. Intermittent operation, in which the furnaces were shut down or "fanned" at frequent intervals.

Jan 1, 1935

By C. R. Johnson, R. A. Greenkorn, E. G. Woods

A new method of reservoir evaluation called pulse-testins has been developed for describing formation properties between wells. Pulse-testing utilizes a sensitive differential-pressure gauge at a responding well to measure and record the response generated by a series of flow rate changes (pulses) at an adjacent or pulsing well. Since the pulse-test instruments have a sensitivity of about 0.001 psi, pulses of several hours or less in duration will generate a measurable response in most reservoirs. For this reason, many well pairs can be tested in a short period of time with little interference in field operations. Comparison of pulse-test results to conventional testing methods shows that the pulses obey unsteady-state, compressible-flow theory and thus provide a measure of both transmissibility (kh/µ) and storage (Fch). In additian, the method can be used qualitatively to describe communication across faults and between zones, and direction and tnagnitude of fracture trends. INTRODUCTION To obtain maximum usefulness of new reservoir analysis methods as well as to aid the field engineer in understanding local reservoir anomalies, improved methods are needed to describe heterogeneities in specific reservoirs. Optimum well spacing, equipment specifications, well completion design and especially the economics of pressure maintenance and secondary recovery programs depend on the extent and location of the heterogeneities that affect flow behavior in the field. One method for obtaining a measure of areal reservoir heterogeneity is an interference test. In the simplest interference test. constant-rate production or injection is initiated at one well and the effect of this flow is measured as pressure vs time at another well. Thus, during interference tests the flow characteristics of the formation are determined in situ. Despite their obvious usefulness in reservoir delineation. interference tests have not enjoyed frequent usage. Reasons for this have been the weeks or months required in many fields to obtain a pressure response measurable with conventional gauges, and the interruption of routine field operation during the field-wide shut-in normally required during these long times. Also, only average properties of the relatively large volume of the reservoir disturbed during these long times can normally be obtained — variations in properties between individual wells cannot be delineated. To eliminate these drawbacks of conventional tests, a special reservoir description technique called pulse testing' has been developed. Pulse-testing has several advantages that make it more convenient and practical for field use than interference tests. Valid tests are more certain because use of a series of flow disturbances gives rise to a diagnostic pressure response that can more readily be distinguished from unknown trends in reservoir pressure and other "noise." The time required is only a fraction of that for an interference test because a special, high-sensitivity differential pressure gauge can detect a much smaller pressure change. Variations in properties between individual wells can be delineated because of the relatively small volume of the reservoir disturbed during these short times. Finally, wells other than the pulsing and responding wells do not have to be shut in or carefully regulated.

Jan 1, 1967

By TRUMAN S. FULLER

THE GREAT INTEREST in decomposition and trans- formation, so evident in the study of alloys during the last two years, was reflected in the many papers on this subject, presented at the first session of the Institute of Metals, Tuesday morning. Dr. F. A. Thomson, of Montana State School of Mines, presented the first paper by C. Wilson, H. F. Silliman, and E. C. Little, "Rate of Precipitation of Nickel Silicide and Cobalt Silicide in the Hardenable Copper-nickel-silicon and Copper- cobalt-silicon Alloys." Dr. R. F. Mehl, in discussing this paper, stated that the title was somewhat deceptive, as it indicated that the rate of precipitation is determined; the method used is a measurement of electrical conductivity and hardness, neither of which is suitable for a quantitative measurement of rates of reaction or precipitation in the solid state. Hardness is also uncertain because it depends so much upon particle size. Of the various methods proposed for the study of rate of reaction and precipitation the evaluation of volume of reaction produced from the area of photomicrograph is the best.

Jan 1, 1933

Jan 9, 1950

By H. Y. Jennings

An extensive field and laboratory experimental program was carried out to compare the waterflood behavior of carefully preserved soft and unconsolidated cores with measurements on the same cores after extraction. Results obtained from using idealized consolidated and unconsolidated porous media in which wettability could be carefully controlled were contrasted with the preserved core data. The controlled tests on idealized porous media investigated the effect of wettability, flood rate, core length, core permeability and consolidation on the displacement of high viscosity oils. It was concluded from these studies that waterfloods are more favorable when carried out with crude oil in preserved soft and unconsolidated cores than with the same cores after they have been extracted and re-saturated. Waterfloods are usually more favorable when carried out with crude oil in extracted .soft and unconsolidated cores than with refined oil of the .same viscosity in the same cores. The less favorable behavior of extracted soft and unconsolidated cores compared to preserved cores is due to alteration of the core by extraction. Preserved cores saturated with native water and oil should be used for laboratory displacement experiments because they more accurately reflect true reservoir behavior INTRODUCTION The demand for low gravity crude oil created by refinery modernization has focused attention on increasing the production of this viscous crude oil. Billions of barrels are in place in fields that are depleted, or nearly depleted, by primary production mechanisms. Since low gravity reservoirs are relatively recent, geologically, the solid matrix material is usually soft and unconsolidated sand. Such formations are also characterized by a high clay content. Evaluation of sophisticated oil recovery processes with the associated high capital investments has increased the demand for special core analysis tests on material from these soft and unconsolidated sand reservoirs. Data in this paper have resulted from an extensive field and laboratory experimental program. The initial objective vras to provide soft and unconsolidated sand cores for laboratory measurements with as little alteration as possible from their reservoir condition. A secondary objective was to compare the waterflood behavior of these carefully preserved cores with measurements on the same cores after they had been extracted and resaturated. When the comparison showed markedly different behavior the final objective was to attempt to explain the difference by making measurements on idealized porous media free of clay in which initial wettability could be carefully controlled. EXPERIMENTS MATERIALS Core Material The preserved cores used in this study were obtained with as little alteration as possible from their reservoir conditions. Special techniques were developed to satisfy this objective. The cores were cut with native crude whenever the crude had the necessary properties to satisfy the minimum drilling fluid requirements. A pure hydrocarbon chromatographic tracer was added to the crude to provide a simple, safe and inexpensive method to distinguish between oil filtrate and formation oil. Details of the tracer technique used in this study and the procedures used to handle and process the soft, unconsolidated cores have been published.' The core samples were then preserved and packaged at the well site with a dip-applied strippable plastic, or by using a rubber sleeve from a rubber-sleeve core barrel. The final step was to insure that the carefully taken and preserved samples were not altered by processing in the laboratory. Some soft and poorly consolidated sands were carefully shaped in the lab and encased in a protective mounting without disturbing their three-dimensional integrity. Many samples were so poorly consolidated that they literally flowed from the package when the seal was broken. A technique was developed to obtain cylindrical plugs from these samples by using liquid nitrogen as the drilling fluid in a conventional core-drill, drill-press assembly. The idealized porous media consisted of sintered rods of Alundum RA 139, outcrop sandstone identified as Al-hambra sandstone and packs of No. 130 Nevada sand. This sand is 95 per cent 140-200 mesh. (Physical properties of these porous media with those representative of preserved cores are in Table 1.) The natural cores and most of the idealized porous media were 1 1/2-in. in diameter and 3-in. long. The samples used to study the effect of core length were 1 1/2-in. in diameter and 12-in. long. Liquids Water and oil produced from the formations being studied were protected from the atmosphere and collected in carefully cleaned glass or plastic-lined containers. The production was free of chemical additives such as emulsion breakers and corrosion inhibitors. The crude oil was

Jan 1, 1967

By O. Jantti, Erkki Laurila, R. T. Hukki

INVESTIGATION of the methods of analyses for magnetite and ilmenite in the Otanmaki iron-titanium ore and respective mill products has resulted in certain improvements in the methods conventionally employed. The outcome of the investigations is summarized as follows: 1—Development of a diamond-drill core analyser for the determination of magnetic susceptibility of drill cores containing magnetic minerals. 2—Development of a magnetite-ilmenite analyser for pulverized products. 3—Development of a potentiometric method of chemical analysis for the determination of iron, vanadium, and titanium in succeeding steps from one test sample. 4—Proposal for a continuous and automatic magnetite assay method. Diamond-Drill Core Analyser The conventional method of assaying diamond-drill cores consists of splitting the cores, pulverizing them and running chemical analyses on representative samples. The physical properties of magnetic minerals, however, offer an entirely different approach to obtain similar final result by the measurement of respective magnetic susceptibilities in a properly designed instrument. This instrument is shown in Fig. 1. Essentially it consists of a magnetic unit, A, and of a meter unit, B. On top of A is a slot where a piece of diamond-drill core C is visible. The magnitude of disturbance in the original magnetic field caused by the magnetic minerals in the drill core can be observed from the microammeter. This reading is a function of the combined susceptibilities of all magnetic grains in the magnetic field. The magnetic unit is built of E-sheets of a shell transformer, as shown in Fig. 2. The primary coil and two identical secondary coils are wound around the central leg and end legs, respectively. The drill core under examination is placed into one of the air gaps as shown in Fig. 2. The number of ampere-turns of primary coil excited by 50 or 60-cycle ac give a maximum induction of about 600 gauss in the air gaps. The secondary coils are connected in series in the opposite direction. Thus their voltages compensate each other if no drill core exists in the air gap or if the susceptibility of the drill core is equal to zero. As soon as the susceptibility becomes greater than zero, the balance of the magnetic circuit is disturbed, resulting in increased voltage in the terminals of coil 1 and in a respective decrease of voltage in the terminals of coil 2. The voltage difference thus produced is a function of the effective susceptibility of the drill core. If the magnetic grains in the drill core are unevenly distributed, the voltage difference varies as the core is rotated around its own axis. The voltage difference is measured with a Bren-tan0 tube voltmeter. If extreme sensitiveness is desired, the established symmetry of the magnetic circuit does not allow reduction of the 0-voltage difference far enough. Therefore a compensatory voltage of a correct phase taken from the terminals

Jan 1, 1952

By Oswald J. Heinrich

THE great improvements which have been made in late years in the different systems and instruments used to perforate the crust of the earth for purposes of testing and exploring for mineral resources or for other reasons, by means of bore-holes of greater or less diameter and to greater or less depths, are manifold. It may therefore be of interest to make an impartial comparison of them, or of such as are most commonly used. Being well aware of the difficulties which are encountered in such a task, a reasonable allowance must be made in such a comparison. It is a rare instance when even two decidedly different systems or instruments have been used in the same locality, penetrating identically the same strata to the same depth. The diameter of a borehole as well as its greater or less depth must also be considered in regard to its cost per foot, etc. But for practical purposes, for ex¬ploration at least, we may assert this rule Any borehole, of whatever diameter, which allows the means of examining the strata most carefully and completely, will be sufficient for this purpose, but that one which will do it most economically and in the least space of time, must be considered the best for it. It will, therefore, partially depend upon circumstances, what system, in spite of other superiorities, may be the best in each case, and the following remarks may aid in deciding this question. To make the attempt here to review all that has been published upon the different systems and means of boring would be out of place. Reference can be had to the able publications treating upon this subject. A difference in this respect exists in regard to the use of the hollow rods in connection with the diamond drill, used for that purpose. The great future, which appears to be evident for this instrument, will be warrant enough for any one, who has had the opportunity to test it, to give his experience to the public. Only in this way can we bring this system to such perfection, as it seems to deserve and * The drawings illustrating this paper are one-half the size of the tools represented, with the exception of the instrument used to reverse the current in the bore-hole (Fig. 17), which is one-third the actual size.

Jan 1, 1874

By Martin Coryell

THIS coal area, and the coal from a limited portion of it, has been known for a long time. In 1817, McClure prepared a geological map to represent the boundaries, and they are not controverted at the present date. In 1834, Richard C. Taylor made a survey and report on portions of the basin. In 1835, Prof. W. B. Rogers was appointed by the State of Virginia to make a geological survey, and made six annual reports in which this area was included; but the re¬ports and maps were not published. R. C. Taylor's Statistics of Coal, published in 1855, gave to the public the details of exploration and production, to date, very perfectly and completely. Daddow and Bannan's work, Coal, Iron, and Oil, published in 1866, repeated the details before given, and advanced some vague theories respecting the coal-field, but gave no new facts. Macfarlane's work, Coal Regions of America, published in 1873, under the head of "Triassic Coal," chapter 27, gives what is known from existing publications of the position, geology, and production of the field, making

Jan 1, 1875

By J. K. Gustafson

MEASURED in terms of ore tonnage, the New Quebec and Labrador iron ore fields promise to rank with the greatest iron ore districts of the world. -- Over 400 million tons of high-grade ore for direct shipping have been discovered to date. Much greater amounts of lower-grade beneficiating ores are indicated by outcrops. Many hundreds of square miles of iron formation await testing.

Jan 6, 1953

THE following employment items are made available to AIME members on a nonprofit basis by the Engineering Societies Personnel Service, Inc , operating in cooperation with the Four Founder Societies Local offices of the Personnel Service are at 8 W 40th St , New York 18, 100 Farnsworth Ave, Detroit, 57 Post St , San Francisco, 84 E Randolph St , Chicago 1 Applicants should address all mail to the proper key numbers in care of the New York office and include 6c in stomps for forwarding and returning application The applicant agrees, if placed in a position by means of the Service, to pay the placement fee listed by the Service AIME members may secure a weekly bulletin of positions available for $3 50 a quarter, $12 a year MEN AVAILABLE Executive Engineer, 37, married, 3 children Now Resident Manager nonmetallic underground mine and processing plant Management and operational experience in gold, copper, zinc, limestone and lime products manufacture Mine plant design and construction, underground mines and quarries Excellent references Currently employed but available reasonable notice Prefer U S M-687-426-E-5-San Francisco Metallurgical Engineer, 29, married, one child, B S Metallurgical Engineering Five years' practical experience in milling and laboratory research Available thirty days Prefer West or Southwest U S A M-689¬522-E-1-San Francisco Experienced Mining Engineer, university graduate, 40, married Twenty years' experience all phases metal mining, past 13 years as manager, excellent cost and safety record Available short notice Best references and complete professional record available upon request M-690

Jan 1, 1952

By Martin Coryell

This coal area, and the coal from a limited portion of it, has been known for a long time. In 1817, McClure prepared a geological map to represent the boundaries, and they are not controverted at the present date. In 1834, Richard C. Taylor made a survey and report on portions of the basin. In 1835, Prof. W. B. Rogers was appointed by the State of Virginia to make a geological survey, and made six annual reports in which this area was included; but the reports and maps were not published. R. C. Taylor's Statistics of Coal, published in 1855, gave to the public the details of exploration and production, to date, very perfectly and completely. Daddorw and Bannan's work, Coal, Iron, and Oil, published in 1866, repeated the details before given, and advanced some vague theories respecting the coal-field, but gave no new facts. Macfarlane's work, Coal Regions of America, published in 1873, under the head of " Triassic Coal," chapter 27, gives what is known from existing publications of the position, geology, and production of the field, making