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By Max C. Eastman, V. H. Wilhelm

California had a record year in production and drilling activity, but the results have not been sufficient to keep up with the enormous increase in demand due to war activity. During the year, 164 dry wildcats were drilled, 80 dry wells in proved areas, 31 gas wells, and 1158 successful oil-well completions for a total of 1433 wells, compared with a total of 765 in 1942. With new discoveries of only 20,000,000 and production of 283,000,000 bbl. for the year, total reserves of California oil have decreased more than 250,000,000 bbl. However, revised estimates of the reserves of old fields indicate an increase in the state's reserves of I00,000,000 barrels. The completion of 1158 wells has served only to maintain the maximum efficient daily rate of production at 800,000 barrels. There is evidence in many fields that oil is being withdrawn too rapidly to obtain the maximum recovery, and more rapidly than is conducive to good production practice. Statistics for 1943 as compared with I942 are shown in the table in the next column, Supply and Demand Steadily mounting needs of the military forces and increased industrial consumption raised total demand for all petroleum products on the Pacific Coast to 914,000 bbl. daily in 1943. That all-time record demand was 149,ooo bbl. daily higher than in 1942 and 214,000 bbl. daily above 1941 demand. Despite restrictions due to shortages of critical material, crude-oil production was boosted from 680,000 bbl. daily in 1942 to 779,000 bbl. daily in 1943, the highest level in 15 years. However, the new crude supply plus natural gasoline production and imports from other states totaled only 840,000 bbl. daily, leaving a deficiency between supply and demand of 74,000 bbl. daily. That shortage had to be made up by withdrawals from inventories, which had been steadily depleted during the previous four years. Aboveground reserves, which totaled 159,574,000 bbl. on Jan. I, 1939, were down to ~8.000,000, bbl. at the end of 1943. Significantly enough, the greater part of that decrease occurred during the last six months of I9437 when more than 23,000,000 bbl. was taken from inventories of both crude and products. Although the size of total inventories on Dec. 31, 1943 might appear substantial, about 65 per

Jan 1, 1944

By Max C. Eastman, V. H. Wilhelm

California had a record year in production and drilling activity, but the results have not been sufficient to keep up with the enormous increase in demand due to war activity. During the year, 164 dry wildcats were drilled, 80 dry wells in proved areas, 31 gas wells, and 1158 successful oil-well completions for a total of 1433 wells, compared with a total of 765 in 1942. With new discoveries of only 20,000,000 and production of 283,000,000 bbl. for the year, total reserves of California oil have decreased more than 250,000,000 bbl. However, revised estimates of the reserves of old fields indicate an increase in the state's reserves of I00,000,000 barrels. The completion of 1158 wells has served only to maintain the maximum efficient daily rate of production at 800,000 barrels. There is evidence in many fields that oil is being withdrawn too rapidly to obtain the maximum recovery, and more rapidly than is conducive to good production practice. Statistics for 1943 as compared with I942 are shown in the table in the next column, Supply and Demand Steadily mounting needs of the military forces and increased industrial consumption raised total demand for all petroleum products on the Pacific Coast to 914,000 bbl. daily in 1943. That all-time record demand was 149,ooo bbl. daily higher than in 1942 and 214,000 bbl. daily above 1941 demand. Despite restrictions due to shortages of critical material, crude-oil production was boosted from 680,000 bbl. daily in 1942 to 779,000 bbl. daily in 1943, the highest level in 15 years. However, the new crude supply plus natural gasoline production and imports from other states totaled only 840,000 bbl. daily, leaving a deficiency between supply and demand of 74,000 bbl. daily. That shortage had to be made up by withdrawals from inventories, which had been steadily depleted during the previous four years. Aboveground reserves, which totaled 159,574,000 bbl. on Jan. I, 1939, were down to ~8.000,000, bbl. at the end of 1943. Significantly enough, the greater part of that decrease occurred during the last six months of I9437 when more than 23,000,000 bbl. was taken from inventories of both crude and products. Although the size of total inventories on Dec. 31, 1943 might appear substantial, about 65 per

Jan 1, 1944

By R. F. Nielsen, D. E. Menzie

The object of this study was to determine if crude oil could be produced successfully by a process of crude oil vaporization using carbon dioxide repressuring. This process appears to have application to highly fractured formations where the major oil content of the reservoir is contained in the non-fractured porosity with little associated permeability. Crude oil was introduced into the windowed cell and carbon dioxide was charged to the cell at the desired pressure. A vapor space was formed above the oil, and the crude oil-carbon dioxide mixture was allowed to come to equilibrium. The vapor phase was removed and the vaporized oil collected as condensate. Samples of all produced and unproduced fluids were analyzed. Tests were also performed to evaluate the amount of vaporized oil that can he produced by rocking from a high to a lower pressure. The carbon dioxide repressuring process was applied to a sand-filled cell to investigate the performance in a porous medium. A test was performed to evaluate how the condensate recovery changes as the size of the gas cap in contact with the oil changes. INTRODUCTION This study has been directed toward a relatively new process of vaporization of crude oil designed to increase ultimate production of hydrocarbons through the application of carbon dioxide to an oil reservoir. Suggested advantages of carbon dioxide repressuring of a petroleum reservoir are: (1) reduction in viscosity of liquid hydrocarbons due to the solubility of carbon dioxide in crude oil, (2) swelling of the reservoir oil into a larger liquid-oil volume with a resulting increase in production and decrease in residual oil saturation due to an increase in the relative permeability to oil, (3) displacement of more stock-tank oil from the reservoir since the residual liquid is a swelled crude oil, and (4) gasification of some of the hydrocarbons into a carbon dioxide-hydrocarbon vapor mixture. Balanced against these advantages are several detrimental factors which must be evaluated; i.e., high compression costs and corrosion of well equipment and flow lines. Some of the more outstanding contributions to the study of carbon dioxide injection have been reviewed in order to furnish a basis for a continuation of research pertaining to this method. The literature reviewed1-8 has been limited to that dealing with carbon dioxide repressuring processes or with carbon dioxide-crude oil-natural gas phase behavior. Articles relating to carbonated water injection and literature published on the use of low pressure carbon dioxide gas injection in water flooding have not been included in this study. In 1941 Pirson5 suggested the high pressure injection of carbon dioxide into a partially depleted reservoir for the purpose of causing the reservoir oil to vaporize and thus produce the oil as a vapor along with the carbon dioxide gas. By reducing the pressure on this produced mixture of hydrocarbons and carbon dioxide at the surface, it was proposed to separate the hydrocarbons from the carrier gas. He theorized that essentially all the oil in a reservoir could be produced by simply injecting enough carbon dioxide to vaporize the residual oil. This present investigation deals with the vaporization of a crude oil by carbon dioxide, the molecular weight and gravity of the vaporized oil product and the characteristics of the residual oil after several repressuring cycles with carbon dioxide. An attempt is made to evaluate the merits of a vaporization process for the crude oil rather than a flow process where the oil recovery is determined by relative permeability considerations. Such a vaporization of crude oil by carbon dioxide repressuring appears to have possible use in a highly fractured formation where the major oil content of the reservoir is contained in the non-fractured porosity with little permeability. The carbon dioxide flows into the fractures, contacts the crude oil in the matrix and vaporizes part of the crude oil; this vaporized oil is produced and recovered and the carbon dioxide is reinjected again. The specific problem of this study is to attempt to answer this question; Can crude oil be produced successfully (technically, but without economic considerations) from a petroleum reservoir by a process of vaporization of the crude oil by carbon dioxide repressuring? DEFINITION OF TERMS AS APPLIED IN THIS STUDY Carbon Dioxide Contact: One cycle in which carbon dioxide was injected and bled off. Condensate: The hydrocarbon liquid which was condensed out of the mixture of hydrocarbon-carbon dioxide vapor upon reduction of the pressure of the vapor. Hydrocarbons Produced (HCP): All the hydrocarbon!, which were vaporized by the carbon dioxide repressuring process and were removed from the cell during any specific cycle or carbon dioxide contact. Hydrocarbons Unproduced (HCU): All the hydrocarbons which were not vaporized by the carbon dioxide

By Edmund Newton

The steel industry of the United States has depended in the past almost wholly upon imports for its supplies of manganese. Many of the important domestic sources yield ores leaner in their natural condition than the foreign ores the steel industry. has been accustomed to use. To make them available, therefore, either the ores must be concentrated or the practice of the steel industry modified. Roughly 25,000 T. annually of high-grade manganese ores are used for dry batteries for chemical purpose, and in other ways; while approximately 750,000 T. are required for making steel. , By present practice, every ton of steel takes an average of about 14 lb. (1.8 kg.) of metallic manganese. This is generally added to the steel in the form of an alloy, the standard alloys being the 80-per cent. ferro-manganese and the 20-per cent. spiegeleisen, During the year 1917, 286,000 T. of ferromanganese and 193,291 T. of spiegeleisen were made in this country, the former largely from imported ores; and 45,381 T. of ferromanganese. was imported. The metallic manganese represented by these alloys was 304,000 T., the product of roughly 800,000 T. of high-grade ore and 345,000 T. of low-grade ore. Manganese Deposits in the United States Before the war manganese ore was mined in relatively small quantities in the Appalachian region, including Virginia, Tennessee and Georgia, and in Arkansas, but owing to the increase in prices during the past three years manganese mining has been undertaken also in Montana, California, Arizona, New Mexico, Nevada, Utah, and Minnesota. From data now available it appears that in this country deposits of high-grade manganese ores are usually small, while materials lower in manganese and higher in iron occur in appreciable quantities. Our total quantity of manganese-bearing material is relatively large, but on

Jan 1, 1920

By Edgar C. Bain

Of the important phenomenon of the hardening of steel, Professor Sauveurl says: It would seem as if the methods used to date for the elucidation of this complex problem have yielded all they are capable of yielding and that further straining of these methods will only serve to confuse the issue, the point having been reached when this juggling, no matter how skilfully done, with allotropy, solid solutions, and strains is causing weariness without advancing the solution of the problem. The tendency of late has been to abandon the safer road of experimental facts and to enter the maze of excessive speculations, in which there is great danger of some becoming hopelessly lost. The conclusion seems warranted that new avenues of approach must be found if we are to obtain a correct answer to this apparent enigma. With some degree of fitness we may say this of other problems. It seems likely that one of the new avenues of approach to many metallo-graphic problems is the study of crystal structure, or more accurately, the atomic arrangement, by means of the x-ray spectrometer. The crystal structure of some materials has been carefully worked out by the mineralogist, but his methods are, in general, unsuited to commercial metals and a method that yields even better information is at hand as the result of work on the diffraction of x-rays by Laue and the Braggs2 and later by HullI3 St. John, and others. It should be understood that the contour of free crystals, which is the subject of measurements by the crystallographer, is the result of the atomic structure and, in general, bears a simple and obvious relation to it. The use of the x-ray spectrometer4 has been described frequently, so the procedure will not be given here.

Jan 1, 1923

By Edgar C. Bain

Of the important phenomenon of the hardening of steel, Professor Sauveurl says: It would seem as if the methods used to date for the elucidation of this complex problem have yielded all they are capable of yielding and that further straining of these methods will only serve to confuse the issue, the point having been reached when this juggling, no matter how skilfully done, with allotropy, solid solutions, and strains is causing weariness without advancing the solution of the problem. The tendency of late has been to abandon the safer road of experimental facts and to enter the maze of excessive speculations, in which there is great danger of some becoming hopelessly lost. The conclusion seems warranted that new avenues of approach must be found if we are to obtain a correct answer to this apparent enigma. With some degree of fitness we may say this of other problems. It seems likely that one of the new avenues of approach to many metallo-graphic problems is the study of crystal structure, or more accurately, the atomic arrangement, by means of the x-ray spectrometer. The crystal structure of some materials has been carefully worked out by the mineralogist, but his methods are, in general, unsuited to commercial metals and a method that yields even better information is at hand as the result of work on the diffraction of x-rays by Laue and the Braggs2 and later by HullI3 St. John, and others. It should be understood that the contour of free crystals, which is the subject of measurements by the crystallographer, is the result of the atomic structure and, in general, bears a simple and obvious relation to it. The use of the x-ray spectrometer4 has been described frequently, so the procedure will not be given here.

Jan 1, 1923

By Joseph Hartshorne

The attention which this process has attracted, especially in Europe, has led me to believe that members of the Institute would be interested in a report of the progress which has been made in the year and a half that has elapsed since my paper on the subject was read at the Colorado Meeting of this Institute. As already described in that paper (Duns., xxvi., 380), this process is a modificatioii of the open-hearth steel manufacture, whether acid or basic, collsistillg essentially in the division of the charge between two furnaces, one of which is charged about two hours earlier than the other, and tapped into the other after the charge in the latter has become fluid, the slag of the first bath being removed from it during the transfer. This description still remains true as far as it goes, but further experience has demonstrated that circumstances will very materially modify the relation of the two furnaces to each other, and the character of the work done in each of them. The function of the primary furnace has become more clearly and entirely that of doing the rough work of desiliconiziug and dephosphorizing, while that of the second or finishing-furnace has become almost entirely that of decarburizing and finighing the heat. To indicate these developments and their results is the object of this paper. In order to avoid needless repetition, I shall try to accomplish part of this object by giving a short resume' of what has been published elsewhere on this subject since my former paper was read. This will at least enable those interested to study the matter for themselves from original sources. Since that time the following papers have been read and published: " The Bertrand-Thiel Process of Making Steel," by Percy C. Gilchrist (Cleveland Institution of Engineers, Session of 1896-

Jan 1, 1899

By Charles R. Keyes

During the past decade the genesis of the lead- and zincdeposits of the Mississippi valley has received special attention from many distinguished observers. But their united egorts, instead of settling all disputed questions, have, in many respects, involl-ed the general problem in greater uncertainty than would be thought possible under the circumstances. In place of the harmony of opinion that might be expected, there is unexpected disagreement, largely due to the fact that, instead of giving attention to a possible multiplicity of ore-producing conditions among the different deposits, the attempt has been made to bring all deposits under a single genetic head. To a new observer of the lead- and zinc-deposits of the Mississippi valley, it appears at the outset that all the deposits cannot possibly have had the same genesis. In fact, different modes of origin have been often asserted for the ore-bodies, but the difficulty has been that each writer has referred them either all to one category or all to another, and no intermediate ground has been considered possible. Such a position now appears to be clearly untenable. The opinion that, in the deposits of the region under consideration, the ore-materials represent original depositions, made at the time the rocks themselves were formed, is no longer held by any authority, and therefore need not be considered here. Of late years, a number of writers have attempted to account for the presence of the lead- and zinc-ores on the hypothesis that the metallic materials arose in heated solutions from the

Jan 1, 1902

By E. S. Wheeler

The conversion plant of the Clirnax Molybdenum Co. is at Langeloth, Washington . County, Pennsylvania, approximately 30 miles west of Pittsburgh. The molybdenite concentrates converted originate in the company's mine and mill at Climax, Co1orado.l They are delivered to the Langeloth plant by rail packed in 175-lb. bags. War production of concentrates at the mill started in 1918 but it was not until about 1920 that any peacetime uses of the metal began to develop. Early conversion of Climax concentrates was mainly into ferromolybden um, produced for the company by a custom smelter. Chronology of Plant Development In 1924 a small hand-rabbled roaster was built at Langeloth, the roasted concentrates being used principally in the production of calcium molybdate by a conventional wet method. The size of the original plant is indicated by the fact that during 1925 about 400,000 lb. of molybdenum was converted. In 1925-1926, a multiple-hearth roaster was erected (12-ft. 0.d. 8-hearth Nichols-Herreshoff); also the first experimental ferromolybdenum was produced at Langeloth. At this time sa.1cium molybdate was produced in the furnace by a process to be described. With continued interest in and increased use of molybdenum, it was necessary to arrange for enlargement of plant facilities. Although only one 12-hearth 16-ft. 0.d. roaster was erected at this time (1929), plans were prepared for a duplicate unit, which was completed in 193 5, giving a potential roasting capacity of some 16,000 lb. Mo per day under the then prevailing roasting practice. Shortly after this second unit had gone into production, increased demand overtaxed the plant, and as a result two 12-hearth 18-ft. 0.d. roasters were placed in operation in 1936 and 1937. This gave the plant a potential roasting capacity of 40,000 to 50,000 lb. Mo per day, and necessitated major changes in auxiliary handling equipment as well as improved facilities for producing ferromolybdenum. Following the introduction (1938) of a new product—molybdic oxide briquets— and because of the constantly growing demand for molybdenum, plant facilities were again enlarged in 1940 and 1941 by the erection of two 16-hearth 18-ft. 0.d. roasters. These two new units, along with a change in roasting practice, brought the potential roasting capacity to 150,ooo to 190,000 Ib. Mo per day, based on about 15 lb. per sq. ft. of hearth area. Other departments of the plant have necessarily grown, until today the plant is modern throughout and completely mechanized, with equipment geared to produce marketable products as follows:

Jan 1, 1944

By Joseph Chalmers, E. L. Rawlins, D. B. Taliaferro

PRoblems dealing with the movement or migration of fluids through porous beds have been the subject of much research. The subject is not peculiar to the production of oil and gas, as many investigators have studied the nature of this movement and its relationship to the problems of other industries. Darcyl conducted a series of experiments relating to the percolation of water through filter beds. King2 carried on an extensive series of laboratory experiments with the object of formulating some conception of the rate of movement of water through soils and sand strata in the drainage of surface water into underground channels and subsequent recovery of this water through wells drilled into the source beds for irrigation purposes. Slichter3 undertook a study of the same problem from a mathematical standpoint, and more recently Furnas4 has investigated the flow of gases through beds of broken solids with particular reference to blast-furnace operation. With specific reference to gas production, Muskat and Botset5 of the Gulf Research Laboratory undertook an experimental study to establish quantitatively the characteristics of and laws governing the flow of gases through consolidated and unconsolidated porous materials of fine texture with a view of predicting the performance of gas in an underground reservoir. There seems to be a general agreement that many of the relationships between the numerousfactors influencing the flow of fluids through porous materials are far too complicated to be attacked by analytical methods based upon a knowledge of hydrodynamics. For gases, the laws of

Jan 1, 1932

By H. R. Barnhurst

It would be a difficult matter to trace from the beginning the very few improvements made in the burning of fuels prior to 1860. Donbtless the crossing of the sticks of wood in building a mood fire early appealed to our savage ancestry as a means of expediting its effectiveness for their crude culinary purposes. Stones and andirons came later in assisting the admission of air to the under part of the fuel bed, while beacons and cressets, utilized metal bars as supports for the same purpose. It is probable that Tuba1 Cain owed his success to the use of bellows making possible the use of mixed fuel and charge upon a hearth. With the development of working in cast iron, grate bars came in, and they are still with us doing duty in every household and almost every art where heat is a factor. Little was done beyond these crude methods prior to 1860. With the advancement of knowledge came the fuel-gas producer, a natural child of the retorts employed in supplying illuminating gas. It is only within the last 15 years that the conclusion became general that complicated systems for saving heat would not remedy deli-. ciencies in its primary development, and within that time there has been great advancement in the means of producing initially a fire of high effciency, so that to-day we are moving rapidly toward both high development and high absorption, with the resultant of high efficiencies. In studying the subject of the availability of pulverized coal as a fuel, it may occur to ask, why has this not come up earlier? This, question would be naturally prompted by recalling the fact that Thomas Crompton's English patents upon his methods were issued to him nearly 40 years ago. A conclusive answer to this, however, is that Crompton at that time had very crude facilities for making what was at best a very imperfect pulverization of the coal, arid the expense of preparation mas very great. He does not seem to have been aware of the advantage of a thorough drying of the coal in the

Jan 1, 1914

By B. W. Veal, B. S. Chandrasekhar

THE Laue method of orienting single crystals requires the use of tables of angles between crystal-lographic planes, and between zone axes. Such tables have been published for cubic crystals, and some rhombohedra12 and hexagonal3 crystals. A table of angles between planes in ß-tin has also been published;4 these angles refer to only low-index planes, and are not particularly helpful in the actual indexing of spots on a Laue photograph. Furthermore, it is often useful to know the angles between zones which share a common low-index plane. We have calculated such tables of angles for ß-tin and indium, both between planes in principal zones, and between zones passing through principal planes. The results are given in Tables I and 11. The standard formulas were used, with c/a = 0.54554 for 0-tin, and 1.07586 for indium.

Jan 1, 1962

By Arthur B. Yates

Diamond drilling has advanced and expanded during the past few yean. Along with this increase there has been a marked trend to rely more and more upon drilling for the outlining of ore for reserve purposes. This is especially true underground, where men have not been available for opening up ore by crosscuts, drifts and raises. During the recent heavy call upon known ore reserves, more drilling has been done for exploration and it has become expedient to drill longer lateral holes from underground and deeper holes both from surface and from exploration headings in the mines. Furthermore, these deeper holes have to be drilled closely enough to warrant calculation of "probable" if not "proven" ore, from the results obtained therefrom. Interpretation of diamond-drill results has become more precise and reliable with the growing knowledge and understanding of the geologic structures that control the geometry of ore distribution, and this has broadened the field of usefulness of the drill. All of this has created a necessity and a demand for more accurate control of the hole as to direction, a more precise and reliable method of surveying for position, and a need for better and more complete core recovery, as well as larger cores, to provide an adequate sample. At depth the control becomes more difficult and, at the same time, more important. Control A close study of drilling in various parts of the world for a period of more than 20 years has brought to light one definite rule, practically invariable; namely, that diamond-drill holes tend to deviate into a position normal to any structure existing in the rocks, such as bedding, schistosity, gneissosity, or even parting or jointing— even if the hole is started at almost any angle other than parallel with the structure. It also appears that the better developed the structure is, the more quickly will the hole get into a position perpendicular to it. It has often been said that there is a tendency for holes to "drift" in the direction of rotation. This is obviously untrue, for in a vertical hole the measure of deviation would depend upon the azimuth chosen as zero, and there is an infinite number of choices. It has been proved. however, that in homogeneous rocks there is a tendency for the hole to corkscrew, and that the direction of the spiral is the same as the direction of rotation. This may account for the belief that holes drift in that direction. Some tests have been made using right-hand and left-hand rods, and these show that no matter what the direction of rotation the hole will swing into a position perpendicular to the structure. Methods of Control The foregoing empirical rule may be used as an indirect method of control. If the prevailing structure is known, it may be advantageous to start the hole as nearly normal to it as possible, for the

Jan 1, 1946

By James B. Fletcher

Leaching of the block caved mine from 1941 through 1970 is described, and the improvements made are listed. Detailed is the increased knowledge of leaching gained through this operation, including methods used in forecasting production, prediction of the economical end point, rate of recovery, and ultimate recovery.

Jan 1, 1972

By Theodore Barry

The task of developing controls in the mining and manufacturing industries to give them a tighter grip on operating costs has afforded this author an interesting vantage point for observing certain practices common to both industries. Of course, each of these industries has problems unique to itself, but all industries have many common problems. After all, every industry is a business and every business is concerned with the task of producing its wares as profitably as possible. While many differences between businesses in different industries are known, the author is convinced through experience that the mining industry has much more in common with the manufacturing industry than is generally acknowledged. Four principal questions come to mind in the comparison of mining with manufacturing: How different are the management control methods in these two worlds? How do both industries go about the task of controlling costs? How does the mining industry compare in terms of the effectiveness of its workers? And perhaps most important, what can the mining industry learn from what the manufacturing industry is doing?

Jan 11, 1962

By H. H. Hausner, S. Storchheim, J. L. Zambrow

The solid state bonding of aluminum to nickel was studied as a function of temperature, pressure, and time at pressure. The initial results indicated that as the reaction conditions were varied, marked changes in tensile strength occurred. Plots of the log penetration coefficient vs the reciprocal of absolute temperature for various isobars were straight lines displaced from each other. THE techniques of bonding different metals to A each other include brazing, welding, welding by application of a molten phase, and solid state welding without any molten phase present. This last technique, the pressing of metals either at room temperature or at some temperature below the melting point of the metals to be joined, seems to offer interesting possibilities for bonding purposes. However, this technique has not been completely investigated, and very little is known about the diffusion phenomena which occur during solid state welding. Some previous work on the effect of pressure on diffusion1 was inconclusive. This paper is concerned with an investigation regarding the effect that the processing variables, such as pressure, temperature, and time at pressure, have in solid state bonding. The tests were made with aluminum and nickel and special emphasis was given to the strength of the bond between these two metals and to the intermetallic penetration rate during the bonding process. It seems that the effect of pressure on the intermetallic penetration is of particular importance for practical purposes and this effect was therefore studied in detail. Procedure Apparatus: The means of solid state bonding used for this study was that of the hot-pressing technique. This method requires the equipment pictured in Fig. 1 and involved the following procedure. The two metals to be bonded were placed in an aquadag lubricated 18-4-1 tool steel die, 16 in. high by 1.440 in. ID, between punches of 1.366 in. diameter made of the same material. A thermocouple

Jan 1, 1955

By Isobel Clark

The increasing complexity of modern mining technology makes it ever more difficult to decide on the 'best* way to solve problems in mine planning. Yet with escalating costs it becomes increasingly more important for the mining engineer to be able to evaluate quantitatively the implications of the 'what happens if' postulation on the efficiency and economics of exploitation. The use of a model of the orebody can yield an estimate, not just of overall expected results, but also of the sensitivity of these results to possible variations in the orebody. Estimation techniques, such as Kriging, will produce the expected value for the grade of ore at any given point, or over any given volume within a deposit. However, the actual grades mined during production will - of necessity - differ from the predicted values. These possible variations, and the sensitivity of the management decisions to them, can be investigated in detail by the use of simulation. An orebody can be simulated which follows the known characteristics of the deposit at any given stage in development. These properties might be the histogram of grade values, the semivariogram from the samples, the actual borehole assays, geological constraints and/or interpretation, topography, lease boundaries etc. This would be one possible 'realisation' of the deposit as dictated by the currently known data. If several of these simulations are carried out, each conditioned to the current knowledge of the orebody, then it is possible to gain an idea of the range of possible outcomes of any mining procedure or decision taken - all of which are equally likely. Not only can the best decision then be taken, but its sensitivity to the inherent variation within the orebody, and to the ever present estimation errors may be thoroughly studied.

Jan 1, 1977

By Charles R. Simcoe

It was pointed out in a recent paper'g that the initial flow stress of as-quenched martensite is very low even in an alloy steel with an M, well above room temperature. It was also shown that the high ultimate tensile strength resulted from a very high rate of work

Jan 1, 1967

By Theodore P. Holt

The Mines Operating Co.'s plant at Park City, Utah, was designed to treat the low-grade fillings in the old stopes of the Ontario mine. These fillings carry 6 to 14 oz. of silver, 1 to 2 lb. of copper, 0.01 to 0.015 oz. of gold, and a small percentage of lead and zinc. The treatment consists in mixing the crushed ore with coal dust and salt and then roasting in a new type of furnace by combustion of the contained fuel. The roasted ore is leached with an acid salt solution to dissolve the silver, gold, copper, and lead. At present these metals are precipitated together on scrap iron and the product sold to a refinery. The only new feature of importance in this scheme of treatment is the roasting process, which makes possible the chloridizing of ores without any loss of the valuable metals, and at a very low cost. History of the Development of the Process The roasting process- had its beginning in connection with research work at the Utah State School of Mines. N. C. Christensen, Jr., who held one of the School of Mines' fellowships, was engaged in some experimental work on blast roasting. At the same time I was doing some work on the insoluble gold in Mercur base ores. Mr. Christensen roasted some of this base gold ore in his pot furnace, and found that when he mixed a sufficiently low percentage of fuel with the ore, it did not sinter but roasted to a leachable product. We considered this a new application of blast roasting, and proceeded to test out a large number of ores in several different types of small roasters which we constructed.. This experimental work continued well into the summer of 1911. In August, 1911, the Consolidated Mercur Gold Mines Co. installed a small roaster of our design, which we proposed to operate on the counter-current principle, feeding mixed ore continuously on top, and at the same time drawing off the roasted ore from the bottom. By proper adjustment we hoped to maintain a permanent roasting zone near the center of the column, the ore moving downward as roasted. However, we

Jan 1, 1915

By O. W. Bilharz

Acid mine-water drainage is a serious problem with many mines in the Tri-State zinc and lead mining district. Particularly is this true when large volumes must be considercd in unwatering old mines that have refilled with water which has dissolved the products of oxidation and has become chalybeate in character. The experiences discussed in this paper have to do specifically with the unwatering of a comparatively small area west of the town of Baxter Springs, Kans., where the pumping job was complicated by water of this type and where the extremely high sulphate content particularly effected that phase of mine drainage having to do with stream pollution. Location, Geology and History The Baxter Springs area of the Tri-State mining field is situated just west of the town of Baxter Springs and is a northeasterly extension of the main mineralized zones of the Oklahoma part of the district (Fig I). The mining area is traversed with well defined shear zones which provide easy circulation of ground waters and the ore bodies are found along these shear zones as localized enrichments wherever the structural conditions are favorable (Fig 2). The ore-bearing strata is Mississippian with an overlain capping of shale of Penn- sylvanian age. This shale strata carries much pyrite and marcasite at its base and undoubtedly was a contributing factor to the subsequent high iron content of the water. The area originally contained a sulphide water which discharged as an artesian flow in springs within the town and gave Baxter Springs its name. These springs were famed for many years for their mineral water. This original sulphide water was first removed about 1917 and active mining was carried on west of the town during subsequent high metal price periods. Many small mines were opened, with each localized enrichment becoming a separate mine. During the depression mining ceased and all mines in the west Baxter area were allowed to flood. No serious effort was made to again unwater until higher prices caused from the demand for metal for World War II once more focused attention 011 this part of the field. Original Mining Results in Oxidation As plans for unwatering progressed, it soon developed that the mine-water pools had become strongly acid in character and carried large amounts of sulphates in solution. This occurred in the following way. When the original sulphide water was removed, shafts sunk, and mining carried on over a number of years, ferrous sulphate was formed by the spontaneous oxidation of the pyrite beds in contact with air admitted through churn-drill holes and mine openillgs. These products of oxidation can be seen today in the old mines of the district as crusts of crystalline sulphates

Jan 1, 1949