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By Ta M. Li

Recent economic and environmental setbacks have not slowed Occidental Oil Shale, Inc.'s program aimed at the commercialization of oil shale. In fact, the firm expects to have a 795 MI (500C) bbl) per day production unit working by the end of 1976. The key to Occidental's ambitious program is an in situ method that extracts the valuable oil by retorting the shale in place. The process will require practically no water and will leave the spent shale in place underground. Additionally, all plant operations are to be located within the mine. These factors thus serve to make the operation attractive from an environmental viewpoint, in contrast to proposed conventional schemes which call for extensive underground mining, crushing and grinding at the surface, and construction of a massive surface retorting facility.

Jan 12, 1976

By T. A. Simpson

The search for ore continued at its relentless pace throughout 1967. Canada, South Africa and Australia plus a few scattered localities on the globe reported minerals finds of significant importance. Many of the reported finds were not high grade ore, but they nonetheless will assist in sup- plying a highly industrialized, mineral hungry world. No longer does inaccessibility and remoteness close an area to mineral exploration and development. The communication and transportation systems of today have closed the gap and, moreover, the demand for essential mineral commodities is causing price shifts which encourage exploitation of deposits heretofore considered uneconomical.

Jan 2, 1968

By John B. Hastings

CHIEF among the varied problems facing the mine-manager is that of vein-structure and origin, which is highly important as a guide to successful discovery and development. If metalliferous deposits can be traced to the intrusion of waters along definite lines, then is there something tangible for him to study. But when he is told by a geologist that metalliferous deposits are due to some other cause, like magmatic differentiation, while not perhaps discouraged, he is impressed with a vague sense of new worlds to be conquered. In 1897, while manager of the War Eagle mine at Rossland, B. C., where, previously, the ore-bodies had not been supposed to occur as veins, I suggested to visiting members of the Canadian Geological Survey that, perhaps, the structure of the pyrrhotite-bodies of that mine, which had been proved to occur along well-defined fractures, might throw some light on the similar deposits of Sudbury, then held to be basic aggregations from the original magma. Later investigation has at least provoked discussion of this last deduction, questioning its correctness and suggesting that, perhaps, the deposits are actual veins. The following extract from a paper by J. E. Spurr 1 is quoted, because it sets forth Mr. Spurr's theory of the quartz-occurrences of the Silver Peak mines, which will be discussed in this article. It also graphically describes the attendant geological features. '' The Drinkwater group of mines, which is the most important part of the Blair gold properties, and which has produced practically all of the million dollars' worth of ore, as above stated, may be taken as typical of the gold-veins which, though widespread and numerous, show a wonderful similarity of character. On the surface two adjacent veins outcrop, the Crowning Glory and the Drink-

Jan 1, 1913

Aamot, Olav Crone, (M'29) Chem. Engr., Elektro¬kemisk, Raadhusgt, 23; Oslo, Norway. Abadilla. Quirico A., (M'33) Min. Engr., Dir., Bureau of Mines, Manila, P. I. Abbott, Agatin T., ( J'40) Asst. Geol., Trench Mine, Patagonia, Ariz. Abbott, Clarence E., (M'04) Civil Engr., V.P., Tennessee Coal Iron & R. R. Co.. 159'3 Brown Marx Bldg.. Birmingham, Ala. Abel, Raymond L., (M'28) Chem. Engr., Chief of Inspection Div., Pittsburgh Chem. Warfare Pro¬curement Dist., American Batik Bldg., Pitts¬burgh. Pa. Abel, Walter D., (M'32) Min. Engr.. Div. of Cor¬porations, State of Calif.. 403 California State Bldg., Los Angeles, Calif. Abele. Louis T., (M'31) 4800 Patterson Ave.. Richmond, Va. Abell, Leo M., (M'311 Research Met., Mount Mor¬gan Ltd., Mount Morgan, Queensland, Australia. Abenius, Hakan V., (M'37) c/o Falu Gruva, Falun, Sweden. Abernathy. G. E., (M '33S) Geol., Kansas State Geol. Survey. Pittsburg, Kan. Abernathy, Jack. H.. (M'40) Chief Engr., Sunray Oil Co.. Philtower B1dg., Tulsa. Okla. Ahorn, Robert H., (M'19) Asst. Met., Research Lab., U. S. Steel Corp., Lincoln Highway, Kearny, N. J. Abraham, A. W., (M'30) Petr. Engr., Richfield Oil Corp., 555 S. Flower St., Los Angeles. Calif. Abramowitz, William L., (J'40) Chem., National Oil Products Co., Harrison, N. J. Abrams, Charles Jackson, (M'36) Gen'l Supt., Climax Molybdenum Co.; Climax, Colo. Abstein, Henry T., (M'27) Yellow Pine, Idaho. Ackerman, D. E., (M'35) McKinsey & Co., 2 Wall St., New York, N. Y. Ackerman. E. Dumont, (A'3S) Petr. Geol.. Dist. Geol., Quiriquire' Dist., Standard Oil Co. of Venezuela, Caripito, Venezuela.

Jan 1, 1941

By John B. Cook

Most of today's open pits take the form of conical-shaped excavations in the relatively flat or undulating terrain surrounding them. Ore is usually hauled uphill from the pit bottom by truck, rail, or skip to crushing, beneficiation, railroad loading, and stockpiling facilities near the edge of the pit. There are, however, a few orebodies whose locations in mountainous terrain causes special problems that generate different technical solutions. LAMCO's 10.5 million metric tons per year high-grade iron mine in the Nimba Range in tropical Liberia is probably one of the most extreme of these exceptions (Fig. 1). At Nimba there is a 2,000-ft difference in elevation between the upper- most levels of the orebodies and the start of the railroad below at the foot of the mountain. Haulage to the crusher is usually downhill at grades of up to 12% dictated by the topography of the rugged terrain. Ore is transported from the crusher down the mountainside by a conveyor sys- tem 10,096 ft long, whose average grade is 18%. The belt is braked by asynchronous generators, feeding power into the local network. The original crusher must be relocated at a lower elevation outside the final pit limit to allow that part of the mountain on which it now stands to be excavated. HISTORY The LAMCO Joint Venture is owned 75% by the Liberian-American- Swedish Minerals Co. (LAMCO) and 25% by Bethlehem Steel Corp. LAMCO is comprised of a 50% interest by the Liberian Government and 50% interest by Liberian Iron Ore Ltd (Fig. 2). This joint venture was launched to develop the high-grade iron ore deposits of the Nimba Range.

Jan 1, 1969

P. Herasymenko (New York University, New York) —The authors' experiments on equilibria between water vapor and liquid synthetic slags represent a valuable contribution to our knowledge of the nature of liquid slags. They can be regarded as a proof of ionic splitting of water molecules dissolved in slags. The assumption that water dissolved in slag was com- pletely ionized was made in my report on hydrogen equilibria in steelmaking as early as 194010. In that paper, the first systematic data were given on the content of ionized hydrogen in acid and basic open-hearth slags. The paper probably escaped the notice of the authors, although they mention the articles published later by other investigators who reported erratic and

Jan 1, 1958

By H. Rush Spedden, A. M. Gaudin

IN the belief that a critical study of its operating problems might be a sound investment, the Cuban American Manganese Corporation initiated an ore-treatment research in cooperation with the Massachusetts Institute of Technology One of the early objectives of this research naturally became the relationship of the microscopy of the Cuban ores of the Corporation to their flotation treatment The operations in Cuba have already been described by F S Norcross, Jr 7 and the laboratory study of manganese oxide flotation goes back a number of years 4 Broadly speaking, the difficulties encountered in the flotation of manganese ores are that the consumption of reagents is extremely high, the concentrate contains more silica than is desirable and the tailing losses are relatively high An appreciable betterment on any of these scores would achieve a definite betterment in costs, quantity of minable ores, and quality of product The microscope study discussed in this paper was made on samples from the Quinto mine, from the Ponupo mine, and from mill products at various stages of passage of the ore through the mill The writers have had access to Company records and in particular to the petrographic studies made on thin sections of ore by the late Professors R J Colony and Philip Krieger, of Columbia University They acknowledge their debt to both of these men for the help derived from the reports Manganese oxides are black, friable, smudging It is therefore, very difficult to judge operations by inspection The mineralogy of manganese compounds seems to be confused, and the authors believe that many more minerals have been described than actually exist Much of this difficulty is due to the prevalence of the structural conditions that will be discussed further in this paper, namely, the porosity and the friability of the ores, and the extremely intimate association of minute manganifeous mineral crystals with impurities of various sorts By all odds the most important manganese mineral in Cuba is the one that in this paper is called "psilomelane " The name "psilomelane" has been used in so many different ways that the choice of it for this ore may not be approved by all However, it seems to be the best under the circumstances This mineral accounts for about 97 per cent of the manganese in the ores of the Quinto and Ponupo mines and in the mill feed The remaining odd 3 per cent consists mostly of pyrolusite together with minor amounts of other manganese oxide minerals DESCRIPTION OF PSILOMELANE Aggregate Structure In grains or lumps, psilomelane has a characteristic fibrous appearance and seems

Jan 1, 1942

By Freeman Bishop

The Bureau of Mines, beset by political woes not of its own making, is struggling to maintain equilibrium as Congress is being made the focal point for repeated charges that the Bureau has "not done a very good job" of setting up and supervising coal mine health and safety standards approved last year by the Congress. Senator Harrison Williams (D- N.J.) is the latest to enter the arena. A crusading legislator, he is now calling for "legislative overview" hearings to judge Bureau competency in matters of coal safety legislation enforcement

Jan 1, 1970

By AIME AIME

IN a recent technical paper of the Central Committee of the French Coal Mines (Note technique No. 198, by L. Lahoussay) the author points out that continuous in¬crease in depth of mine shafts makes it more and more necessary to look for appropriate means to reduce the weights and dimensions of the hoisting ropes. Increasing depth demands a larger section and weight for the cable if the useful load is not to be cut down at the same time. This naturally leads to increased cost per ton, and at the same time creates serious mechanical difficulties. The dimensions of the hoisting engine must be increased, acceleration at the start must be decreased so as to avoid periods of excessive peak power loads, and a longer time be allowed to slow down the speed of the hoist when applying brakes. The hoisting rope, upon which depend the dimensions and hence the mass of the hoisting engine, presents the greatest obstacle to the development of hoisting from greater depths. Evidently, for a given depth, the total weight of the rope can be notably reduced by utilizing a wire rope of decreasing section, approaching the theoretical logarithmic form. This is a solution frequently adopted for great depths. Of course, the weight of the rope could be easily' diminished by reducing the useful load, but it is certain that with increasing depth of mining, more effort must be made to confine the hoisting to a small number of shafts, and increase the load hoisted per trip.

Jan 1, 1933

By R. L. Wiegel

The two questions considered in this study are: (1) what similarity is there in the liberation of magnetite from various iron formations, and (2) how is this liberation affected by the size reduction technique employed. Twelve sample suites were obtained from commercial concentrators processing magnetite iron formation in the United States, Canada, and Australia. These samples have grades in the range 15 to 45% magnetite iron and approximate mineral grain sizes o f 50 to 2000 microns. Efforts were directed at measuring the liberation characteristics of the samples obtained from the concentrators primary grinding mills. The Davis tube, a laboratory magnetic separator, was used to concentrate individual size fractions of the size reduction product to determine liberation data. These liberation data were compared with relationships calculated from a highly idealized mathematical model of liberation in a binary mineral system. The results of these comparisons have been encouraging for nine or ten of the twelve samples tested. This leads to the conclusion that for most commercial iron formations, at least with conventional rod mill size reduction, it is possible to quantitatively characterize liberation with two parameters: an effective mineral grain size and ore grade. Limited laboratory size reduction tests as well as one of two sets of liberation data from commercial primary autogenous grinding lend some support to the contention that autogenous grinding can affect mineral liberation.

Jan 1, 1976

By John V. Beall

During the last quarter of 1948, two new machines, which may revolutionize the coal mining industry, made their first public appearance within two months of each other. Both are designed to mine and load coal continuously. On Oct. 27, the "Colmol," invented by C. H. Snyder and A. E. Lamm, president and executive vice-president, respectively, of the Sunnyhill Coal Co., was demonstrated at the No. 8 mine of that Company at New Lexington, Ohio. The "Joy Continuous Miner," invented by H. F. Silver, president of the Silver Engineering Works, Denver, and developed and manufactured by the Joy Manufacturing Co., was demonstrated at the Mathies mine, near Finleyville, Pa., in the Pittsburgh coal seam.

Jan 1, 1949

By R. T. Hukki

IT is no great exaggeration to say that present grinding practice and economics are largely determined by lining design. A record of outstanding liner wear can be achieved with any liner surface pattern that will positively lock the outer layer or layers of grinding media. With no slippage, lining wear is bound to be slight. At the same time, popular practice calls for tumbling loads of about 50 pct of mill volume to obtain maximum grinding capacity. Innumerable parallel grinding investigations have verified that optimum speed for such a mill lies within 70 to 85 pct of theoretical critical speed. If the mill is speeded up to 100 pct of critical, little or no grinding can be accomplished. Earlier Work on Supercritical Grinding: First investigations concerning grinding at supercritical speeds seem to be very old. Remarkable work on the subject has been performed by White,&apos; and his experiments have been described and summarized by Richards.&apos; White&apos;s contributions seem to have passed unnoticed by Fahrenwald,2,3 whose extensive experiments have been well presented, yet apparently very little appreciated. Additional work on grinding at supercritical speed has been reported, e.g., by Lewenson and Tscherny,&apos; USSR; Anselm and Grunder,&apos;, Germany: and Rose and Evans." Great Britain. Subcritical and Supercritical Speeds: In the formula of the critical speed given in the textbooks of mineral dressing, no factor indicating the coefficient of friction is generally included. If this factor = 1.0, which is equivalent to grinding conditions in a mill provided with heavily ribbed lining, the formula of the critical speed holds as such and grinding is possible at subcritical speeds only. In a mill equipped with a smooth or relatively smooth lining, the numerical value of the friction factor in the denominator of the formula becomes <1.0, indicating that grinding at supercritical speeds should be possible in such mills. It has been recently shown by the author&apos; that a wide supercritical speed range will become available for grinding—and especially for fine grinding—if the basic conditions within the mill have been selected properly. Mathematical analysis of mill dynamics at supercritical speeds&apos; has indicated that the mill speed may be increased if: 1) total mass of grinding medium decreases, 2) mass of the individual grinding piece increases, and 3) the coefficient of friction between the outer layer of medium and the mill lining decreases. It is obvious that the mass of the individual grinding piece will be affected by its shape and by its specific gravity. The coefficient of friction decreases with: 1) increasing smoothness of liner surface, 2) increasing roundness of the grinding piece, 3) increasing fineness of material to be ground, 4) decreasing pulp density, and 5) decreasing hardness (abrasiveness) of the mineral to be ground. In a mill equipped with heavily ribbed lining, practically no size reduction will take place between the lining and the outer layer of tumbling medium, because slippage is prevented. In the overwhelming majority of today&apos;s mills the grinding accomplished is by virtue of cataracting and/or cascading media with some action within the tumbling charge. Sub-critical speeds only can be applied. In grate-type or peripheral discharge mills equipped with a smooth lining a tumbling load of any kind of common medium occupying about 50 pct of mill volume will behave in such a way that practically no slippage will take place. This has been verified in experiments run by the author in the laboratory and in pilot plant mills&apos; equipped with smooth lining. Again, the operation is limited to the subcritical range. In a mill with a smooth lining, grinding will be possible either at subcritical speeds or within a wide supercritical speed range as soon as the basic requirements for a desired speed are fulfilled. In a mill operated at supercritical speed, any point on the liner surface proceeds at a speed greater than that indicated by the formula of the critical speed, while any grinding piece situated in the outer layer of the medium against the lining proceeds in the same direction at a speed less than that indicated by the critical speed. This speed difference produces a very effective attrition grinding zone between the liner surface and the outer layer of the medium. The share of attrition grinding of the total grinding accomplished increases rapidly with increasing speed in the supercritical speed range. The smooth surface of the mill lining may be well illustrated by the surface of a bucking board. The outer ball layer may be similarly represented by the lower surface of a muller. If the bucking board, the material to be ground, and the muller all proceed in the same direction at the same speed, no grinding will result. This is the general situation in the mills of today. If, however, the muller is pulled with respect to the board, moving or stationary, grinding will be accomplished effectively. Although grinding in today&apos;s mills is primarily the result of cataracting and/or cascading media, the principal place of grinding at high supercritical speeds will be the attrition zone.&apos; In the mineral dressing laboratory of the State Institute for Technical Research. Helsinki, Finland, large quantities of different ores have been ground in a pilot plant ball mill (3x3 ft) at a top speed about 230 pct of the critical. With the same mill, theoretical investigations concerning the grinding characteristics of ball mills equipped with a smooth lining have been carried out up to the speed of 313 pct&apos; of the critical. With a smaller mill, the grinding characteristics with a variety of grinding media have been investigated at speeds up to 2000 pct of the

Jan 1, 1959

By W. S. Row

This mine is operated at 4000 to 4500 tons daily through a single shaft, with one rock hoist and one service hoist. Latest shaft construction is concrete with wooden dividers. Economics of drifters and air-leg drills are compared, as well as costs of shrinkage and sub-level stoping. Economy of large haulage equipment and underground crushing is shown.

Jan 3, 1953

By Francis P. Sinn

LOW prices have made 1938 a difficult year for the zinc industry of the world. Particularly in the United States, output had to be radically curtailed to bring production into line with consumption. Despite these unfavorable conditions, some additional plant construction is contemplated. In Jugoslavia, through co-operation with the Government, Trepca Mines is lo build a zinc plant to produce 10,000 metric tons annually, the plant to be ready for operation in July, 1941). Cerro de Pasco is proceeding with its plans for an electrolytic plant in Peru. A pilot plant, to be ready next summer, is under construction. In eastern Canada an electrolytic plant is planned in Quebec to treat concentrates from Yoranda and other mines but no defi-

Jan 1, 1939

By David W. Brunton

(San Francisco Meeting, October, 1911.) MINE-DRAINAGE and the ever-increasing demand for water on the plains have within the past few years necessitated the driving of a great number of adits and tunnels, including many of considerable size and great length. In most instances, ex isting conditions have called for extreme rapidity of execution; and this necessity, coupled with the high altitudes at which most of the work has been carried on, excessive freight-rates, and difficulty -of access, has involved many complex and interesting problems. One of the most rapidly executed undertakings of this class is the Laramie tunnel, recently completed for the Laramie-Poudre Reservoirs & Irrigation Co. This tunnel is driven through Green ridge, a spur of the Continental Divide, which separates the Laramie river from the Cache-la-Poudre in Laramie county, Colo. Green ridge is extremely persistent, and further northward in Wyoming is known as Sherman hill, the highest point on the Union Pacific railway. At the point where the tunnel is driven, two opposing bends bring these streams within 2.5 miles of each other, with a difference in elevation of 500 ft. The rock exposed on the banks of the two rivers does not differ materially in hardness; and, without a geological study of the conditions involved, it would appear that the difference in the depth of erosion of the two streams is due principally to the greater volume of water at this point in the Cache-la-Poudre, which has a drainage-area above the tunnel-portal of 110 sq. miles, as against 30 sq. miles of natural drainage for the Laramie. To increase the water-supply at the tunnel, however, this latter amount has been augmented by two side collection-canals, which bring the available drainage-area up to 84 square miles. The nearest railroad shipping-point to the eastern portal is

Apr 1, 1912

By Robert L. Slobod

In much of the work reported in the literature on long cores. true connate water value, probably have not been obtained because of insufficient flow of 011 to attain equilibrium. A -.satisfactory method for establishing connate water in long cores has been developed in which oil flow is maintained until no additiona1 water is displaced. INTRODUCTION Long cores have been used by sev-erals investigators in an effort to evaluate the efficiency of oil recovery for various producing schemes. The effects of many variables such as rate of displacement. pressure drop, volume of displacing medium, gas-oil ratio, inter-facial tension, and others have been investigated, and the merits of gas drive have been compared with water drive. In the older experiments no connate water was used. but in the more recent stndies the philosophy of the experiment calls for a core containing oil and connate water (irreducible water) as the starting point of the experiment. The method generally used to establish this condition in long cores involves dynamic&apos; displacement wherein one or more phases are forced through the core. flow being maintained at a constant rate or at a constant pressure until a steady state is reached wherein there is no change of saturation with time. It is one purpose of this paper to point out that in much of the work reported in the literature true connate water values probably have not been obtained. The reason for this failure is pointed out. and a method for obtaining more reliable connate water values on long cores is presented. It is impossible at this time to completely evaluate the effect on the conclusions in the earlier papers resulting from the failure to obtain true connate water in the long cores, but some data are presented which indicate that serious errors may he present in many cases. MATERIALS AND APPARATUS Cores cut front outcrop sandstones (Strawn. Torpedo, and Elgin sandstones) with permeabilities of the order of 300 md were used. The major experiments were made with a core 18-in. long and 2-in. in diameter. Cores of the same diameter but only 12-in. long were used in a few tests? and in some work a core I-in. in diameter and 11-in. long was used. These materials were all somewhat bentonitic. &apos;To reduce the effect of such constituents, one of the cores (Torpedo No. 10) on which the most work was performed was acid extracted at the start of the experiment. Brine containing 50,000 ppm chloride and naphtha (Stoddard&apos;s Solvent) were used as the water and oil phases, respectively. The core was mounted in a rubber sleeve which forms the inner lining of a brass cylinder. In this arrangement2 the rubber sleeve is forced against the core by applying pressure to water in the annular space between the rubber sleeve and the brass cylinder wall. The core is therefore sealed in rubber so that all fluids introduced at the input end of the core flow through the core. With this equipment the core may be easily removed for inspection and analysis. Also, other cores may be introduced for study with no extra time for preparation such as is required when plastic mounting is used. When pressure or conductivity measurements are desired at intermediate points along tile length of the core, the brass cylinder comprising the outer jacket of the core holder is cut into section, of the desired length. Each section is then made up as an individual unit with its own rubber sleeve (see Fig. 1). The individual units are then butted up against a ring of plastic or other insulating material which carries an electrical contact for resistivity measurements and an opening which can be used for the measurements of fluid pressures. The individual units are forced tightly against the plastic ring separators and held in place with several tie rods. Inlet and outlet end butts of the same diameter as the core and several inches in length are provided to control the introduction and withdrawal of fluids and to complete the arrangement for sealing the core within the rubber sleeve. Fluid flow is maintained either by applying pressure to the liquid confined in a reservoir or by the use of a gear pump. The latter is preferable where continuous flow at a moderate rate over a long time interval is desired since a small volume of liquid can be readily recirculated using filters to prevent plugging of the core. EXPERIMENTAL The oven-dried core is weighed and is then completely saturated with brine

Jan 1, 1950

By F. X. Tartaron

F. C. Bond (Consulting Engineer, Processing Machinery Dept., Allis-Chalmers Manufacturing Co., Milwaukee, Wis.) — Papers such as this one which deal in a lucid manner with the obscure fundamentals of comminution theory are always welcome. The author has attempted to bring together several diverse theories and handles them interestingly. However, some of the ideas expressed and conclusions drawn require critical reviewing, for which amenities alone will not suffice. The author points out that the theoretical energy required to break across crystal lattices is of the order of 1000 times the actual energy required to crush or grind, and that this energy in turn is perhaps 1000 times the measured surface energy of the new surface area produced. The energy required to grind commercially is controlled by flaws and dislocations, rather than by the inner strength of the lattice structure. The measured surface energy is only a slight residue left after the face atoms are adjusted to their new environment. The dislocations in the crystal lattice structure, with a spacing of about O.l,u, or

Jan 1, 1962

By Richard McCaffery

WHEN we began the study of blast furnace slags we limited our work at first to a study of those slags containing only lime, alumina and silica. On our paper1 on some of the results of this first work, the solubility of sulfur in slags containing no magnesia was reported and the question of sulfur solubility and slag viscosity discussed. There has been, for a long time, a very great difference of opinion among metallurgists as to he effect of magnesia in blast furnace slags, and the literature is full if expressions of the most contrary opinions on the subject. As a result, our next publication&apos; developed the constitution of slags considered as a four-component system, silica-alumina-lime-magnesia, and advanced an explanation of slag structure which accorded with the facts and with scientific theory. The present paper continues our study of the general subject of slags. As blast furnace slags are included in the silica-alumina-lime-magnesia system, which is a particular case of four-component solutions, we have determined that there are 22 components Table 1), which may enter into the silica-alumina-lime-magnesia system and that 10 or 12 of these components may be present in blast furnace slags which are within the ordinary ranges of composition. To cave a very definite conception of the behavior of these components in a slag, we have developed the theory of the cooling of a four-component solution from the liquid state to the solid and the conclusions that we obtained have been made use of in this paper. On account of the importance of the four oxides and 18 compounds which enter into the silica-alumina-lime-magnesia system, some method of calculating the percentages of the various compounds that are present in the slag when the percentages of the oxides are given, seemed very desirable and we develop L method later herein for doing this, and finally we give illustrations of the composition of a wide series of blast furnace slags and show some applications of these composition data.

Jan 1, 1927

The eastern part of the state of Rhode Island on both sides of Narragansett Bay, including the island of Rhode Island, is underlaid with carboniferous rocks which carry veins of anthracite. This formation extends into the neighboring portion of Massachusetts, including the area from the state line, the towns of Mansfield, Brockton and Bridgewater,: and extending probably ten miles east of the latter two towns, to Middlesboro, and to Fall River. In Massachusetts the coal formation extends over nearly the whole of Bristol, and parts of Plymouth and Norfolk Counties. In Rhode Island and Massachusetts the area covered is about 400 square miles. In both states the exact limits of the coal measures cannot be determined on account of a thick layer of drift which overlays it. Along parts of Narragansett Bay, the coal measures outcrop in the cliffs on the west side of Rhode Island, and the presence of coal here seems to have been noted as early as 1760, and in 1768 a patent was granted to parties who "were about to dig after pit, coal or sea coal" at the back of the town of Providence. In 1807-08 Benjamin Silliman, later a geologist, visited some openings,&apos; and in 1808 a mine was opened near Portsmouth, in the northeast part of Rhode Island. Work was done here until about 1814 when the mine was abandoned. No anthracite had been used in New England at that time, all coal used came from Nova Scotia, Virginia or England, and was high volatile bituminous; neither experience nor the means of firing favored the use of the local fuel? This mine was again working in 1827, was again abandoned and operations were resumed in 1847. In 1837 a note in a magazine mentions, "the immense coal mine in Cumberland-about six miles from the city of Providence" as having a shaft 14 ft. in diameter and 80 ft. deep, that the horses then used for hoisting the coal were to be superseded by a steam engine and another shaft was to be sunk. With these improvements 30,000 to 50,000 tons were to be produced the following year at a cost of $1 per ton and a sales realization of $6.1 Hitchcock&apos;s report refers to a number of localities in both states where definite knowledge of coal existed. These are:

Jan 1, 1942

By Arthur F. Wendt

The hot-blast oven of which the accompanying plate gives complete details, was designed by the writer for the spiegel-furnace of the Lehigh Zinc and Iron Co., at Bethlehem, Pa. Members of the Institute who visit these works will have occasion to notice the large amount of zinc-dust in the gases, and the consequent dirtiness of both the hot-blast and the boilers. The zinc collects in a crust on the iron hot-blast pipes and leads to the frequent burning of them. A large vertical standing-pipe stove, a modification of the "Pleyer," thus gave considerable trouble by the burning of pipes and, on one occasion, the toppling over of a whole row. These inconveniences are avoided in the hanging-pipe stove under consideration, and less heating-surface has been found to be required to heat the blast to a given temperature. The construction of the stove is so simple and so plainly shown in the plate that it is needless to enlarge upon it. Each pipe rests in a box and is connected by U-branches with the next adjoining pipes. An iron sleeve is placed around the joint and tightened, as usual, with iron filings. In case of a pipe burning out, that particular section is cut off by the valves and the sleeves are broken. The pipe is then readily lifted out of the box and a new one is substituted. The whole operation requires only a short time and the section can then be at once put into use. The boxes supporting the pipes cover the whole surface of the hot-blast and are closed by iron covers rammed with fire-clay. Owing to the air-space around the U-pipes there is little loss of heat in the upper part of the stove. Each section as built has 280 square feet of heating-surface. The furnace is blown by a horizontal engine with 46-inch stroke and 48-inch diameter of blowing-tube. At 28 to 30 revolutions, the engine delivers 3000 cubic feet of air per minute, at a pressure of 5 pounds. When five sections of stove are in use, the blast enters the furnace at a temperature of 850" F. That is, there are over two cubic feet of air per square foot of heating-surface heated to that temperature per minute.

Jan 1, 1887