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By L. D. Frink

THOSE actively interested in mining are fully aware of the ever-increasing difficulty of making conditions such that efficient work can be clone in underground openings, especially as higher rock temperatures are encountered in depth. This is also true where an effort is being made to cut down the burden of overhead expense by working headings 24 hr. in a day if blasting is done as often as is possible in that time. That the conditions resulting from both these causes have driven the native-born Americans from the mines and that their places have been taken by less efficient foreigners is a fact that we must all admit. The great war now being fought in Europe and the educational qualification clause written into our immigration law by the last Congress will probably limit very materially the supply of labor, such as we are now using in our mines, and will force upon mine operators the necessity of making this work appeal again to Americans. Metal tubing, with blower or exhaust fans, has long been used in supplying air to dead ends where natural ventilation is impossible, or in driving the smoke from such places, or in doing both, as the need might be. Here in Butte we have now come to use canvas tubing very extensively and find that it has many advantages not possessed by the metal. The use of flexible tubing is not new, but it has not been generally used in mining operations. Recent improvements, however, in the canvas itself and in the jointing of sections and manner of suspension have so increased its usefulness that it promises to add much to the efficiency of mining. There is now on the market a product that is impervious to air, is fireproof, and has a system of jointing which, permits it to be put up or taken clown in a few seconds. In this article an effort will be made to explain the manner in which canvas tubing is being used in the North Butte company's operations at Butte, Mont. The accompanying photographs will, I hope, help make clear what may be done with this material.

Jan 1, 1918

By S. K. Nowak

The lithium solubility limit in solid aluminum was determined by the use of micro-graphic techniques. The solubility limit thus established was shown to be a true equilibrium by checking the reversibility of AlLi phase precipitation and dissolution around the equilibrium temperature. The experimental results fit a straight line by plotting log N(LI) against 1/T. The metallurgical reasons explaining the lack of agreement among previous investigations are discussed. THE solubility limit of lithium in solid aluminum was determined by Shamray and Saldau1 by micrography and by Grube et al.' and also Voss-Kiihler- by measurement of electrical resistivity. Since the addition of lithium induces extremely small changes in the aluminum lattice, X-ray techniques could not be employed for this purpose; in fact, the addition of lithium does not cause an expansion of the lattice as might be expected from a consideration of atomic radii, but causes a small contraction from 4.040 to 4.037A3, 4 when the solvent aluminum is saturated with this element. An analysis of the results from previous investiga-tions'" shows that with improvement of investigation techniques the solubility limit tends toward a lower lithium content. Again, some of the author's own experimental results on the action of atomic hydrogen on A1-Li alloys seemed to indicate that the solubility of lithium should be much lower, i.e., about 0.3 pet at 300°C: instead of 1.15 pet, the lowest published value.4 For the foregoing reasons it was decided to investigate this problem. The aluminum and the lithium used for this purpose were of the highest purity. The lithium solubility limit was determined by metallographic techniques, in particular by the use of a reagent especially developed for the purpose of revealing the AlLi phase. The solubility limit thus determined was shown to be a true equilibrium by checking the reversibility of AlLi phase dissolution and precipitation around the equilibrium temperature. All of the experimental work was carried out in 1951 at the Centre d'Etudes de Chimie Metallur-gique at Vitry, France, under the direction of Georges Chaudron.

Jan 1, 1957

By C. T. Van Winkle

MINE fires are always dangerous and are frequently accompanied by loss of life during the period of confusion which is apt to follow their discovery. In metal mines, fires may result from the accidental ignition of some combustible material, or they may be of spontaneous origin resulting from the rapid decomposition of sulphide. They occur frequently enough to demonstrate the need of some special equipment and a general plan for controlling them, in addition to measures for their prevention. Nearly all the large copper mines have had fires, and the methods of fighting them have been well described in recent papers, notably-by C. L. Berrien,1 R.. E. Tally,2 and others in discussion. The Copper Queen mine has many shafts, which are connected by underground workings. The deeper parts are ventilated by fans, but in the shallower portions natural ventilation through numerous connecting raises or shafts is sufficient. There have been several fires in the past few years, of which all are extinguished but one, and that is under control. These notes cover particularly the preparations that are being made-to check a new fire, partially or temporarily, and to facilitate the escape of workmen in the interval before a definite plan of fighting it can be established. A fire may occur in a shaft or station, or in some working father away. In case of fire in an upcast shaft, the gas would escape to the surface and the immediate result would probably not be dangerous to workmen, as they could escape by other shafts. In a downcast shaft, however, the gas would be distributed very rapidly throughout a large portion of the mine, and men might easily be trapped and asphyxiated. A fire in mine workings, drift, raise, or stope, would be dangerous in a degree, but the draft there is likely to be less strong than in a shaft and probably a smaller area would be invaded by the fire gases.

Jan 1, 1918

By M. Van Siclen

THE outstanding fact in connection with dust disease in the United States at present is the growing recognition of its seriousness by state officials and by the more progressive operators of mining, metallurgical and allied industrial plants. The same may perhaps be said of labor in some of its better organized centers, but the average independent non-union workman continues, as of yore, to suffer the toll of disability and even of death from dust inhalation without realization of the source of his ill-being. Progress in the betterment of the handling of sufferers from dust disease and of the conditions creating dust hazards in mining and allied industries is pursuing a course similar to that of the now widespread campaign against accidents, in which the risk is more obvious, more severe, and was naturally recognized. sooner. The coming on of dust disease is generally relatively slow and its immediate effects not infre-quently masked by or attributed to other diseases. Marked exceptions to this general rule have occurred in districts where the dust is particularly pernicious, such as the Rand and Joplin; yet such exceptions, unhappy in themselves, opened the eyes of medical men, and of those in other localities charged with the responsibility for the welfare of industry, to the much more widespread if less spectacular hazard existing from the inhalation of dust in all rock-excavating operations and all industrial operations creating inorganic dust, whether it be crushing and grinding, sand-blast-ing, granite-cutting, or what not. Advancement to date in the United States in prevention and treat-ment has been slow, yet the record shows that quantitative methods for determining the degree of hazard and means for decreasing it were being developed as far back as 25 years ago; and that more rapid progress may be looked for from now on. In 1908, in this country, F. L Hoffman?(1) discussed the mortality from consumption in dusty trades, especially brass foundries; and in 1913 E. R. Hayhurst(2) described the effects of inhalation

Jan 1, 1933

By Joseph E. Pogue

Price is a complicated concept, for price is both a cause and an effect. This reciprocal aspect is commonly overlooked and the oversight is the source of many economic maladjustments. Price is the resultant of the ratio between supply and demand, but it differs from a mathematical concept of a proportion, by itself constituting an economic force which continuously alters the elements that determine the relationship. Price, therefore, is not merely the outcome of other forces but is in its own right one of the most powerful of economic agents. Price accordingly does not play a passive role; nor can it be sterilized or rendered inactive. In consequence, price cannot be fixed or at least kept fixed, except by the elimination of all freedom of choice on the part of producers and consumers. A primary objective of all economic activity is equilibrium. The same is true of a unit of economic activity, the single industry. The plane upon which equilibrium centers may shift in the course of time, but equilibrium itself is the point of departure and the point of return. If an industry is in equilibrium, that industry is operating effectively. The motivating forces of an industry—profits or the common good—are not to be confused with the prerequisite of equilibrium, but this mistake is often made. The producer is dominated by the profit motive; the consumer, or his collective representative, by the general welfare motive. No one is the advocate for equilibrium; that status is supposed to be arrived at automatically. If the forces of competition are perfectly free, such is the tendency. Equilibrium For the purposes of this analysis, equilibrium needs to be broadly defined and is conceived to involve: (1) balance between supply and demand; (2) internal equipoise amongst the elements within an industry; and (3) symmetry in respect to the whole economy. This definition implies flexibility and case of adjustment; a ready accommodation to change. Equilibrium does not postulate profits or nonprofits, social objectives or the lack of them. A decadent industry may be in equilib-

Jan 1, 1937

By Paul M. Tyler

Fully a decade ago, demand for ground mica began to exceed supplies of scrap mica from manufacturing operations and of waste block from feldspar and sheet mica mining in the United States, with the result that in recent years the market has absorbed larger and larger quantities of mica recovered as a by-product from clay washing,1 as a joint product with kyanite12 and by grinding schists. So far, only schists that contain a large percentage of mica have been utilized for making ground mica, but already there has been a good deal of wishful thinking with regard to recovering mica as an aid to the prospective working of low-grade gold ores and ores of certain base metals. With wet-ground mica selling at $60 to $100 a ton and even dry-ground mica worth over $20 a ton, many ores that could not be considered as otherwise workable under present conditions will show commercial possibilities if they can be made to yield even a relatively small percentage of salable mica. An interesting paper might be written on the coming role of industrial minerals as joint products of metal mines. It is largely a matter of markets. Many years ago I watched the mess left behind the gold dredges in the mountains of Colorado and thought of the Denver sand and gravel operators who prided themselves upon their canniness in providing devices for catching gold merely as an incident to their regular business of selling what we miners classed as "tailings." Nowadays almost every milling or mining operation near settled communities finds use for at least part of its waste for road material or concrete aggregate and several eastern iron mines have gone into the crushed-stone business. Promoters now mention fertilizer "filler" as potentially salable at all the way from $1 to $10 a ton, or whatever is needed to cover costs of mining and treating the "ore" and leave the metal values as "clear profit." In emulating the pork packers in their efforts to utilize "everything but the squeal," mining engineers may go too far; on the other hand, they should not let

Jan 1, 1942

By Paul M. Tyler

Fully a decade ago, demand for ground mica began to exceed supplies of scrap mica from manufacturing operations and of waste block from feldspar and sheet mica mining in the United States, with the result that in recent years the market has absorbed larger and larger quantities of mica recovered as a by-product from clay washing,1 as a joint product with kyanite12 and by grinding schists. So far, only schists that contain a large percentage of mica have been utilized for making ground mica, but already there has been a good deal of wishful thinking with regard to recovering mica as an aid to the prospective working of low-grade gold ores and ores of certain base metals. With wet-ground mica selling at $60 to $100 a ton and even dry-ground mica worth over $20 a ton, many ores that could not be considered as otherwise workable under present conditions will show commercial possibilities if they can be made to yield even a relatively small percentage of salable mica. An interesting paper might be written on the coming role of industrial minerals as joint products of metal mines. It is largely a matter of markets. Many years ago I watched the mess left behind the gold dredges in the mountains of Colorado and thought of the Denver sand and gravel operators who prided themselves upon their canniness in providing devices for catching gold merely as an incident to their regular business of selling what we miners classed as "tailings." Nowadays almost every milling or mining operation near settled communities finds use for at least part of its waste for road material or concrete aggregate and several eastern iron mines have gone into the crushed-stone business. Promoters now mention fertilizer "filler" as potentially salable at all the way from $1 to $10 a ton, or whatever is needed to cover costs of mining and treating the "ore" and leave the metal values as "clear profit." In emulating the pork packers in their efforts to utilize "everything but the squeal," mining engineers may go too far; on the other hand, they should not let

Jan 1, 1942

By Paul M. Tyler

FULLY a decade ago, demand for ground mica began to exceed supplies of scrap mica from manufacturing operations and of waste block from feldspar and sheet mica mining in the United States, with the result that in recent years the market has absorbed larger and larger quantities of mica recovered as a by-product from clay washing,1 as a joint product with kyanite12 and by grinding schists. So far, only schists that contain a large percentage of mica have been utilized for making ground mica, but already there has been a good deal of wishful thinking with regard to recovering mica as an aid to the prospective working of low-grade gold ores and ores of certain base metals. With wet-ground mica selling at $60 to $100 a ton and even dry-ground mica worth over $20 a ton, many ores that could not be considered as otherwise workable under present conditions will show commercial possibilities if they can be made to yield even a relatively small percentage of salable mica. An interesting paper might be written on the coming role of industrial minerals as joint products of metal mines. It is largely a matter of markets. Many years ago I watched the mess left behind the gold dredges in the mountains of Colorado and thought of the Denver sand and gravel operators who prided themselves upon their canniness in providing devices for catching gold merely as an incident to their regular business of selling what we miners classed as "tailings." Nowadays almost every milling or mining operation near settled communities finds use for at least part of its waste for road material or concrete aggregate and several eastern iron mines have gone into the crushed-stone business. Promoters now mention fertilizer "filler" as potentially salable at all the way from $1 to $10 a ton, or whatever is needed to cover costs of mining and treating the "ore" and leave the metal values as "clear profit." In emulating the pork packers in their efforts to utilize "everything but the squeal,"

Jan 1, 1938

SAMUEL L. HOYT.-The question of adding the ferromanganese to the ladle or to the furnace involves both theoretical and practical questions and its discussion might very easily occupy the rest of the day. One of the points to be kept in mind is the desirability of obtaining uniform steel. If ferromanganese is added to the ladle, it is necessary first to melt the manganese and then to distribute uniformly throughout the heat. The only heat available for this purpose is that of the molten steel itself. No doubt sufficient heat is present, but in our desire to pour the steel as quickly as possible there is hardly sufficient time allowed, many times, for the proper distribution of the manganese. In other words, this is an operation which takes a certain amount of time and any undue shortening of the time allowed must affect the quality and uniformity of the steel. Again, this particular method does not lead to as efficient a use of the manganese as might be desired; a contention which is based on theoretical grounds. In concentrated solution, manganese will completely reduce all the ferrous oxide, the presence of which I hypothecate and produce, as the reaction product, manganese oxide. In dilute solution, the manganese only partly reduces the iron oxide, but the manganesee oxide which does form dissolves the iron oxide in simple solution. The dissolution of ferrous oxide in the manganese oxide will result in a more economical utilization of the manganese and an equal purification of the heat. This whole point, at present, has not been definitely proved and its answer will involve very difficult research work. On the other hand, if the manganese is added to the furnace, the heat of the furnace is used to melt the alloy and there is plenty of time during tapping for the manganese to be very uniformly distributed throughout the steel. By distributing the alloy throughout the charge we can secure a better utilization of the manganese than is possible if the addition is made to the ladle. Certain other points, such as the recovery, have been dealt with at greater length in the paper.

Jan 4, 1919

By John Birkinbine

Much has been contributed to the Transactions of the Institute concerning the construction and operation of American blast-furnares ; but the following compilation is offered as possibly furnishing additional information upon the general features, dimensions, locations, capacities, etc., of the blast-furnaces of the United States; while, incidentally, the ores upon which they rely are noted in a general way. The paper is presented chiefly as a compilation, and the figures given are selections from most reliable sources, or averages calculated from official statistics, placed for convenient reference, with a view of assisting those who consult the Transactions in determining the present relative merits and importance of various sections of the country. The scope of the paper has been restricted to as few topics as possible, and all the details of special plants, or notable outputs have been ignored. While every effort has been made to give correct figures and data, the changes which are constantly taking place in the iron-producing industry, will, undoubtedly, by the time the paper is in print, develop some errors. It is difficult to determine which of the blast-furnace plants of the country should or should not be considered as upon the active list. A number which have not been in operation for years are still reported as active, some of which will scarcely be put in blast again, and others are handicapped so that they can only operate in times of abnormal profits. It is therefore scarcely probable that there are over 600 blast-furnaces in the United States which can properly be considered as active; but so many considerations affect the various plants, that, it being impossible to determine the exact number, I have relied upon the annual reports presented to the American Iron and Steel Association. Concerning the number of plants which could be stricken from the list, the Secretary of this Association says: "In January last (1885) we enumerated 669 furnaces, which included many stacks which had not been in blast for a very long time, and others which could not be operated except during short periods of exceedingly high prices for pig iron. We have gone over this list very carefully and have eliminated 10 anthracite, 19 bituminous, vol. xiv.—36

Jan 1, 1886

By A. F. Lucas

EACH day, the fact becomes more evident that the ever-growing demand for oil is farther outstripping production, regardless of the increase in output throughout the past twenty years. The development of known oil fields and the prospecting for new ones along present lines are not resulting, in, and cannot bring forth, supplies large enough adequately to meet the oil needs of the country. The usual methods of prospecting-for new supplies are insufficient to meet the exigencies of the situation which threatens, in the not distant future, to reach a critical stage. Were it not that within the last two years new and prolific oil fields have been discovered in northern Louisiana, central Texas, and California, this crisis would undoubtedly be now at our door. Stocks are being exhausted in spite of the rapid growth of imports. The time is therefore fast approaching when some radical departures must be made in the method of prospecting and developing old and new fields in order to increase our oil supplies. Methods and chances, that have seemed unwarranted will not only be given serious consideration, but, according to the results promised, will be put to the test. Meanwhile, however, nearly all the oil fields are responding to the stimulus of higher prices, whereby enormously growing capital is attracted to this important industry, both here and abroad; the increase in our petroleum production at the present time is due to this circumstance. Yet, although a most active search is being made for possible sources of additional supply, one section of our country is not yielding the results that, in my opinion, it is capable of producing: I allude to the coastal dome belt of Texas, Louisiana, and Mexico. The United States Geological Survey has estimated that three-fourths of a billion barrels are available in the ground in the Coastal Plain of the two states just mentioned. Numerous papers have been written on the subject of the salt domes of the Coastal Plain and more or less attractive theories have been advocated by leading geologists to account for their origin and the presence of the oil, sulfur, and salt associated in them. However, owing in part to the generally monotonously level country in which the coastal

Jan 9, 1920

By M. Gensamer

IT has been suggested by a number of people that it would be worth while for some one to attempt to summarize or condense the proceedings of this symposium. This task has fallen to me as organizer and co-chairman. Its difficulty will be appreciated by anyone who attempts to read the whole proceedings. It is therefore with trepidation that I offer the following digest. In recent years there has been a renewal of interest in America on this subject of the cohesive strength of materials, and a growing appreciation of the need for a better theory of cohesion failure. The theories of elastic action and plastic action are well developed, particularly the former. The theory of plastic action is still in the course of development, but it is well along. Plastic action is terminated by cohesion failure and what is needed is a theory that will tell us when to expect the cohesion failure. In the past it has generally been assumed that cohesion failure will occur when a critical value of the maximum tensile stress has been reached. Many experiments have shown that this is not strictly true, and this symposium concerns itself with the failures of this simple hypothesis, and with the efforts that have been made to devise a more satisfactory theory. The most active contributor in recent years to knowledge in this field is Dr. McAdam, and he was asked to open the symposium with a summary or condensation of his papers and views. Undoubtedly it is presumptuous to attempt a still greater condensation, but perhaps it will be useful, because even his contribution to this symposium contains no summary, no concise statement of just what his contribution has bees. Dr. McAdam makes two main points. The first is that the cohesive strength is not a single valued quantity, but that it is a function of all three principal stresses and hence must be represented diagrammatically by a surface in a three-dimensional figure. Dr. McAdam has attempted so to delineate the cohesion limit, basing his

Jan 1, 1944

By M. Van Siclen

THE outstanding fact in connection with dust disease in the United States at present is the growing recognition of its seriousness by state officials and by the more progressive operators of mining, metallurgical and allied industrial plants. The same may perhaps be said of labor in some of its better organized centers, but the average independent non-union workman continues, as of yore, to suffer the toll of disability and even of death from dust inhalation without realization of the source of his ill-being. Progress in the betterment of the handling of sufferers from dust disease and of the conditions creating dust hazards in mining and allied industries is pursuing a course similar to that of the now widespread campaign against accidents, in which the risk is more obvious, more severe, and was naturally recognized sooner. The coming on of dust disease is generally relatively slow and its immediate effects not infre-quently masked by or attributed to other diseases. Marked exceptions to this general rule have occurred in districts where the dust is particularly pernicious, such as the Rand and Joplin; yet such exceptions, unhappy in themselves, opened the eyes of medical men, and of those in other localities charged with the responsibility for the welfare of industry, to the much more widespread if less spectacular hazard existing from the inhalation of dust in all rock-excavating operations and all industrial operations creating inorganic dust, whether it be crushing and grinding, sand-blast-ing, granite-cutting, or what not. Advancement to date in the United States in prevention and treat-ment has been slow, yet the record shows that quantitative methods for determining the degree of hazard and means for decreasing it were being developed as far back as 25 years ago; and that more rapid progress may be looked for from now on. In 1908, in this country, F. L Hoffman?(1) discussed the mortality from consumption in dusty trades, especially brass foundries; and in 1913 E. R. Hayhurst(2) described the effects of inhalation

Jan 1, 1933

By H. I. Meyer, D. F. Searcy

INTRODUCTION The analysls of our previous paper' on the behavior at two immiscible fluids separated by gravity into two dlstinct saturated zones in the porous medium was shown to be theoretically valid only if one of the two fluids was immobile. The practical problems associated with flow of both phases have so far been impossible of solution by these analytic methods. We, therefore, decided to resort to a simulator study to answer the following pertinent questions: 1. If the lighter fluid is produced from a point above the fluid-fluid interface, how long will it take for the heavier fluid to come up to the point where production of both fluids is taking place? 2. After steady-state two-phase production is established, what is the relative production rate of each phase, on what physical variables does this depend, and what are the boundary conditions at the outflow face? 3. A third question was at least partially answered in the course of this investigation: that of the shape of the interface under flow conditions. These questions are of fundamental importance in the fields of hydrology and the reservoir mechanics of oil and gas production. In order to simplify equipment used and still retain a fair physical representation of these phenomena, it was decided to use a Hele-Shaw type of analogy in which the flow took place between two vertically mounted pieces of plate glass. The advantage of this system is that it eliminates any surface effects between the matrix of the porous medium (e.g. packed sand) and also allows equilibrium conditions to be established more quickly. The principle disadvantage (apart from the obvious one of being one more step removed from the prototype) is that our equipment limited us to two dimensional flow studies. In spite of these limitations answers to the questions were obtained which seem adequate for our purposes. We would like to see more work of this nature done to verify and to improve our conclusions. DESCRIPTION OF EQUIPMENT AND PROCEDURE A drawing of the equipment used in this study is shown in Fig. 1. Fluid flow takes place between the two 36 in. x 12 in. pieces of plate glass held apart at the long edges by two spacers of cellulose acetate sheet (Kodapac IV) which is available in several thicknesses. This sandwich was clamped together by small c-clamps whose stress was distributed by long pieces of 3/8-in. keystock. Accurate spacing was obtained by tightening these clamps as indicated by micrometer measurements on the outside of the glass. At the upstream end of the plates a piece of 6-in. diameter pipe simulated an infinite reservoir, while at the downstream end a 2-in. Lucite cylinder with a small hole near the top of the flow region served to drain the fluid. Sealing was achieved by O-rings, the whole system being tightened by pressure on the Lucite tube provided by set screws (not shown in the drawing). The total head

Jan 1, 1957

By J. D. Price, W. M. Bertholf

One of the chief difficulties with which the operator of a coal washing plant has been forced to contend is the handling of the very fine coal. First he has the problem of separating the fine coal from washery water. This is usually accomplished by the use of settling cones or Dorr thickeners: in either event the separated fine coal contains a high amount (40 to 80 pct) of water and, somewhat loosely, dependent upon the size of the coal particles present, may be known as sludge or slurry. His second problem is the satisfactory further dewatering of such separated sludge and/or slurry. At the coal washing plant of the Colorado Fuel and Iron Corp., washed coal from the Deister Plat-O tables is sluiced to a stationary inclined de-watering screen provided with 3/16 by 1-in. slots, and the coarse coal passing over this screen is conveyed by a Baum-type elevator and a flight-type distributing conveyor to a battery of Carpenter centrifugal driers. The fine coal and water passing through the openings of the primary dewatering screens, plus the fine coal passing through the screens of the centrifugal driers (and no small portion of which is the result of the disintegrating action of these driers) is pumped to two 30-ft Link Belt settling cones. The sludge recovered as underflow from these cones was formerly dewatered on stationary screens having 1/16 by 1-in. slots and discharged on top of the coarse washed coal in the Baum drainage conveyor; but after a relatively few hours of op eration the circulating load of fine coal on this conveyor built up to a point where it became necessary to reduce the quantity of feed to the washing tables. The original arrangement of our coal washing and dewatering equipment is shown in Fig 1. In order to regain the loss in active throughput which had been caused by this circulating load, an installation of six vibrating filters was made during the year of 1936. This resulted in an increase in normal tonnage of washed coal from 1430 to 1750 tons per 8-hr shift, a gain of slightly over 22 pct. This increase in throughput has made a very substantial decrease in the " conversion cost" per ton of washed coal. Since the vibrators were installed, we have gained about 2,000,000 tons in production, compared to what would have been produced in the same number of shifts at the former rate. Putting it in slightly different form, we have saved in the past 12 yr the cost of 1400 operating shifts in the washery. Fig 2 shows the location of the vibrating filters as applied to the original flowsheet. It will be noted that the sludge from the bottom of the settling cones is passed through a distributing box and thence to the filters. The de-watered coal from the filters is de-livered to the conveyor receiving the dried coal from the Carpenter driers.

Jan 1, 1950

By GEORGE W. HARHIS

IN the earlier period of anthracite-ruining, much coal was wasted, both underground and in the culm-banks on the surface. Such waste is common in the development of new mining districts, in which, as a rule, only the richest material can be profitably treated. In the anthracite-region, special causes operated to increase this evil. The mines were generally operated under 20-year leases, and royalties were paid upon such coal only as was actually marketed. The lessees consequently cared for immediate profit only. They were- not bound to win all the coal they exposed, or to leave it in such condition that their successors could win it. Nor was it their interest or duty to educate consumers in the use of their product. The market called for coal of large sizes ; and such coal they furnished, throwing away the rest. Any pains taken by them to bring about a more rational use of coal by their consumers would have borne fruit, after their leases had expired, to the benefit of somebody else. A full statement of the situation wits given in 1893, in the report of the State Commission, appointed in 1889 to investigate the subject.` That body included the names of Heber S. Thompson, William Griffith and the late Eckley B. Coxe.2 Its report gives special attention to the utilization of the old culm-banks.

Nov 1, 1905

By Stanley L. Lopata, Eric B. Kula

SEVERAL methods are available for determining pole figures by X-ray means.' The earlier film methods have been replaced by techniques in which the intensities are measured by Geiger counters on an X-ray diffractometerZm7. These methods utilize either flat transmission or reflection samples,214°8 cylindrical specimens,3 or spherical specimens.7 A single transmission or reflection sample will not yield information over the complete pole figure. The cylindrical specimens suggested by Nortod and the spherical specimen of Jetter and Borie7 have the advantage of allowing the whole pole figure to be obtained without any corrections to the intensity for absorption, There is a lower limit to the size of sheet which can be conveniently studied, however, and sample preparation can be rather tedious. Probably the most common method today for determining the complete pole figure is that developed by Schulz. A flat reflection sample is used for determining the pole figure from the center out to about 70". Because of the geometry of the system used, little or no correction for absorption or irradiated volume is necessary.4'6 A separate transmission sample is used for the region near the edge of the pole figure. This procedure requires two separate samples, one of which must be a thin carefully-prepared transmission sample. Furthermore, since the reflection and transmission data are in different arbitrary intensity units, a region of overlap must be obtained, and the intensity data from one set of measurements converted to units of the other. These are serious disadvantages of this method, and they point out the need for a simplified procedure. Since the reflection technique can be used for planes whose normals lie up to about 70° from the sample surface normal, it is apparent that a complete pole figure can be obtained by reflection alone if sample surfaces are cut at oblique angles to the rolling plane Specifically, if a rolled sample is cut so that the normal to the surface formed lies equidistant (54" 44') from the rolling plane normal, rolling direction, and transverse direction, then complete information for one quadrant of the pole figure can be obtained by reflection from the surface. Fig. 1 shows this oblique surface, as well as the position of the pole of this surface in the pole figure. When a surface has been cut oblique to the rolling plane, the standard polar stereographic net is inconvenient to use, and it would be more desirable to have the center of the net coincide with the pole of the oblique plane. Fig. 2 shows such a net, where the center has been offset 54' 44' to correspond to a specimen cut as in Fig. 1. This net was in effect obtained by rotating a standard polar stereographic net 54" 44' with the help of a Wulff net. With the experimental setup used. a sample can be cut from plate of 1/2-in. thickness or br Gen- erally thinner sheet is under investigation, and a composite specimen must be used. A convenient procedure has been to bond together, using epoxy resin, sufficient sheets to form a cube. These are clamped in a vise, and when dry, the whole vise is rotated and a flat surface ground at the required angle. The sample is then mounted inside a larger steel ring using Koldmount, the backside ground flat and parallel to the approximate desired thickness. The sample is then polished and etched to remove any effects of cold working during grinding. With this method only one quadrant of the pole figure is obtained. Often pole figures show symmetry around the rolling and transverse directions, and any slight asymmetry is due to scatter. Should the pole figure not be symmetrical, four oblique surfaces, corresponding to the four quadrants of the pole figure, would have to be examined. In most cases there is symmetry at least around the rolling direction, which reduces to two the number of quadrants to be investigated. For many purposes all that is required is an average polefigure for the four quadrants. This canreadilybe obtained with composite specimens of sheet material, where sheets Corresponding to each of the four quadrants can be intermixed. The four quadrants can be obtained by considering sheet in the normal position, and by rotatiolls of 180" around the sheet normal, the rolling direction, and the transverse direction. If desired, the whole thickness of the sheet can be used, yielding an average of the surface and interior textures; or the surface material can be removed from each sheet, resulting in a pole figure for the center alone. Eugene S. Meieran of the Massachusetts Institute of Technology has independently developed the same method. His results, adapted to a pole figure goniometer with a specimen spiraler, will be described in another publication.

Jan 1, 1962

By J. R. Thoenen

If asked whether limestone production was a mining problem I would not hesitate to answer emphatically in the affirmative. The question, "When is a quarry a mine?" is familiar. The immediate mental picture induced by the thought of limestone production is that of an open quarry. All are familiar with the open pit in the iron-producing districts of Minnesota and Michigan and the open cuts of the so-called "porphyry" coppers of the West. If these are mines, they differ little from limestone quarries in general mode of operation; if quarries, why do they need the attention of mining engineers? During 1923, the United States produced in round numbers 70,000,000 tons of iron ore. The limestone production of the United States for the same period was something over 100,000,000 tons. In tons, it about equals the oil production of the United States. The uses of limestone are legion. A paper read by a prominent engineer of Chicago, at the meeting of the National Crushed Stone Association held last February in St. Louis says: "There is no industry in the United States today that is more basic in its operation or by itself controls more industries. There is hardly a chemical operation, hardly a metallurgical operation or building operation that a crushed-stone man does not control if he will jump in and make the full utilization of it." Some of the many uses are for road metal, concrete, railway ballast, building stone: riprap, and rubble, the manufacture of iron and steel, alkalies, calcium carbide, magnesia, carbolic and carbonic acids, asphalt filler, mineral wool, poultry grit, sulfuric acid, phosphates, nitrates, soap, baking powder, the purification of copper and prevention of coal-mine explosions, to say nothing of the quantities used in the making of lime and cement. It has been said that without iron we would revert to the Stone Age; how much iron would we have without limestone? From the point of view of the mining engineer, using the term in its broad sense to include geologists and metallurgists, the production of limestone is important because of its occurrence, volume, commercial importance, and the problems presented by its recovery and treatment.

Jan 1, 1925

TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen:-To a Board of Directors keeping in as close touch with all of the affairs under their care as do the Directors of the A. I. M. E., through their monthly meetings, a report of the year's progress is almost superfluous. ' To the members who read the monthly reports of the Board Meetings and of the various activities of the Institute as published each month, a yearly report cannot carry much fresh information; yet for both it may be well, as is the custom, to glance over the field of our activities during the past year, and to make an estimate for the year to come. The beginning of 1924 was not propitious for the members of the mining profession, though tonnage production for 1923 had been high and the gross value higher than for several years. The margin of profit had been narrow, prospecting and development were limited, and many of our members were unemployed or were working in other industries. Toward the end of the year, higher metal prices were in sight. Old-time optimism began to grow, and it now brightens the outlook for 1925. An excellent barometer of the prosperity of the industry, and that of the Institute, for they go hand in hand, is the work of our Employment Bureau. During the past few months, the percentage of our members for whom openings have been found has been increasing to a marked extent, and many members who had fallen in arrears are placing themselves in good standing. The number of new members joining has remained about as it was in 1922 and 1923. The Directors have reason to congratulate themselves on the interest maintained during a dull period, for it is not humanly possible to take a keen interest in the technology of an industry when our hands and minds are not actively engaged in it Now, with a much brighter outlook, we can look forward to a year of increasing prosperity for the industry and for the Institute.

Jan 1, 1925

By W. D. Von Gonten, R. L. Whiting

Regression analysis was used to correlate the physical properties of 478 sandstone and 90 carbonate core samples. Porosity, permeability, electrical formation resistivity factor, capillary pressure and the sonic velocity of the shear and compressional waves were measured. Prediction equations for porosity, permeability and electrical formation resistivity factor were found which should be useful in understanding the relationships between the physical properties of porous media in formation evaluation. INTRODUCTION The physical properties of porous media are important to the petroleum engineer and geologist. To evaluate fully the potential and behavior of a subsurface formation such as a petroleum reservoir, certain physical properties of the porous medium must be known. The problem of accurately determining physical properties of subsurface formations has not been solved because many determinations must be made by indirect measurements and because of the difficulties caused by complex pore structure and presence of clays in most naturally occurring porous media. Due to the difficulty in measuring some of the physical properties of porous media, it would be advantageous to be able to predict a certain physical property of a rock from other physical properties of the rock which could be measured more easily and more accurately. Since most potential reservoir rocks are heterogeneous, relationships between the physical properties are very complex and thus far no satisfactory correlations based on theory or laboratory models have been developed. It appears that empirical relationships obtained by measuring the physical properties of a large number of samples of naturally occurring porous media and applying regression analysis to develop equations for one physical property in terms of other rock properties is the best approach. REVIEW LITERATURE The three physical properties used as dependent variables for correlating purposes were porosity, permeability and formation factor. Since formation factor is more difficult to determine, a brief review of the literature is provided on this property. The first work on determining formation factors was published by Archie1 in 1942. He defined this property of a porous medium as F - Ro/Rw......(1) where Ro is the resistivity of the porous medium when completely saturated with a brine of resistivity Rw. Archie found the best correlation between formation factor and porosity was the following equation, where is the porosity fraction and m is the constant characteristic of the rock. The value of m was 1.3 for unconsolidated sand packs, and ranged from 1.8 to 2.0 for consolidated sandstones. In 1950 Patnode and Wyllie2 and De Witte3 observed that the formation factor as determined by Eq. 1 was valid only when the porous medium contained no conductive solids such as clay or shale. When conductive solids are present the formation factor is also dependent on the resistivity of the saturating fluid. Therefore, in samples containing conductive solids the formation factor decreased as the resistivity of the saturating fluid increased. Because of this. the measured formation factor was called the apparent formation factor and was designated Fa. Patnode and Wyllie proposed the following equation,