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By Y. C. Liu, W. R. Hibbard

An aluminum single crystal cold-rolled from (110) [1121 essentially retains its initial orientation after 99.6 pct reduction in thickness. The orientation of the recrys-tallized grains of this material can be described in terms of crystallographic rotations about principal poles of deformation texture. DURING the study of the recrystallization of a copper single crystal cold-rolled from a (110) [112] initial orientation, the orientation of the re-crystallized grains could be derived by a 30" rotation of the orientation of the cold-rolled matrix about its <111> poles.&apos; The present investigation was undertaken to extend the work done on copper&apos; to an aluminum crystal also cold-rolled from a (110) [112] initial orientation. Experimental Procedure The procedure of this experiment was similar to that reported for copper.&apos; An aluminum (99.998 pct) single crystal rod* 1 % in. in diameter was grown in back-reflection technique.&apos; The specimen (1.20x 1.004x0.6787 in. thick) was then rolled along the [112] direction. The final thickness was 0.0028 in., giving a reduction in thickness of about 99.6 pet. Specimens were cut from the rolled strip with scissors, and approximately in. of disturbed metal was removed with Tucker&apos;s reagent. The rolling edge remained intact. The specimens were sandwiched between two graphite plates and annealed in a lead or lead alloy bath which was electrically heated. Pole figures were constructed using the techniques previously described.&apos; Specimens were electrolytically polished4 and etched with 47 pct HNO8, 50 pct HC1, and 3 pct of 48 pct HF. The electrolytic polishing method and etching reagent employed for aluminum specimens were not entirely satisfactory and the microstruc-tures could not be studied in any detail. Results and Discussion The octahedral pole figure of cold-rolled aluminum strip is plotted in Fig. 1. The <111> poles spread in the transverse direction approximately 8" for the highest intensity areas. The spread in the transverse direction can be related to a rotation about two <110> directions lying in a plane containing the rolling direction and rolling plane normal. The two <110> directions and a scale of rotation for the <111> poles are shown in Fig. 2. The amount of rotation is consistent for three of the four <111> poles, about 35" to 40". The discrepancy for the fourth pole is believed to be due to limitations of the film technique. Alternate inter-

Jan 1, 1956

By G. C. Weaver, G. T. Harley

BEDS or lenses of potash and magnesium salts are found in a thick salt section (Salado) overlain by Rustler Red Beds in several members of which water is present and from one of which the refinery process water used by International is obtained. Most of the holes drilled are less than 1000 ft. deep, but some wildcat holes have exceeded 3000 ft. Cable or rotary tools are used to drill down to the salt. When samples of water are desired the cable rig is used, but when this is not necessary, and where caving material is present, the rotary rig has an advantage. The rotary rig has a further advantage in that only one machine is required to drill and core the entire hole, whereas the cable rig must be moved off to make way for the core drill. Casing is placed in the upper section of the hole as required to shut off water, and a 5 3/16-in. string is set in the top of the salt before coring starts. With the rotary rig drilling is often carried to the salt with no casing, as drilling mud seals off caving ground and water-bearing strata, and a string of 4-in, line pipe or 4-in. flush-joint casing is landed on top of salt. Several types of gasoline-powered core rigs have been used in the field and all recover a 2 1/2-in. core. More recently the Sullivan Model 37 rotary rig has been tried, and a Sullivan Model N has been adapted to use a rotary bit in the upper section. Core is recovered in 20 ft. sections with a double-tube core barrel, and the bit used is a bottom-discharge type set with diamonds. The drilling fluid must be a saturated brine to prevent solution and etching of the minerals present. Blowouts are apt to occur from nitrogen gas trapped under the several polyhalite beds, and some have been strong enough to blow the tools out of the hole. Core recovery is practically 100per cent. All holes are plugged after drilling, with cement through the salt section and opposite each water horizon, and mud through the remainder of the hole. Cores are carefully logged and preserved, and in sections containing potash and magnesium minerals they are quartered and analyzed. The correlation of ore beds between drill holes is briefly described.

Jan 1, 1946

By Walter Stern

THE self-potential or spontaneous polarization method is one of the oldest in the field of electrical exploration. When applied in prospecting for ore bodies, it is one of the most rapid and inexpensive means of locating indications of ore bodies at shallow depth. Usually, the procedure is to survey the equipotential lines of the electrical field that is generated by the electrochemical activity of the ore near the ground-water level, and to localize the so-called negative centers or points of greatest negative anomaly. Another field procedure involves the measurement of potential differences along potential profiles, generally laid out at right angles to the assumed strike. Again, in such survey, the basis for establishing the presence of ore is the location of negative potential anomalies. The earlier writers on the subject, notably Schlumberger1 and R. G. Wells,2 did much to clarify the fundamental electrochemical phenomena involved. Interpretation of the field data, however, remained largely qualitative. In 1925, A. Petrovsky3 analyzed the relation between the shape of the potential anomaly curve and size and depth of an ore body by assuming the subsurface body to be a polarized sphere.4 Along similar lines of approach, Edge and Laby5 considered the ore body a dipping sheet with limited extent in the direction of strike, while Poldini6 based the theory on the assumption of a dipping bar. The following study endeavors to enlarge [ ] FIG. I.-ORE BODY CONSIDERED AS DIPOLE upon these earlier investigations and attempts, on the basis of the potential distribution of a polarized bar, to indicate certain characteristics of the anomaly curve that make possible the determination of depth, size and dip of a subsurface body. THE SPONTANEOUS POLARIZATION FIELD SET UP BY AN ORE BODY If a sulphide ore body is subjected to oxidation varying in degree in its upper and lower parts according to the difference in the concentration of oxygen within the surrounding medium, an electrical potential field is set up. The form and distribution of this field will be investigated herein with special reference to its components on the earth&apos;s surface. Under the simplifying assumption that the ore body may be considered as a dipole with the point sources QI and Q2 situated at its upper and lower ends (Fig. I), the potential of the spontaneous polarization at point P is given by the following equation:

Jan 1, 1944

By R. C. Buehl, J. P. Morris

ACTIVITY values for sulphur dissolved in liquid iron and slags as functions of composition and temperature are needed in applying thermodynamics to sulphur-control problems in iron- and &apos; steel-making. The purpose of this investigation was to determine the effect of carbon on the activity of sulphur in the metal phase. The method employed was the same as that used in an earlier investigation&apos; concerning the effect of silicon on sulphur activity in liquid iron. A study was made of the conditions of equilibrium in the reaction between hydrogen gas and sulphur dissolved in iron-carbon alloys. The chemical equation for this reaction can be written as follows: S (in liquid Fe-C alloy) + H2 (gas) = H2S (gas). It was found that the activity coefficient of sulphur in liquid iron increases as the carbon content increases. At 2.3 pct carbon and 1600 °C, the activity coefficient of sulphur is twice its value in carbon-free iron, and at carbon saturation it is more than six times as great. The effect of temperature on sulphur activity was found to be small. Previous work on the reaction between hydrogen gas and sulphur dissolved in liquid iron has been reported by several investigators2,³,4 but only recently have studies been made of the effect of alloying elements. Silicon1 is known to have a pronounced influence on the activity of sulphur in iron, its effect being similar to that shown by carbon as described in the present report. Kitchener, Bockris, and Liber-man5 recently have published a preliminary report of their work on the effect of carbon on sulphur activity in iron. Their experiments were made at 1570°C and carbon saturation in the melt. Under these conditions they found that the activity coefficient of sulphur was approximately doubled by the presence of carbon. This is a much smaller effect than that found in the present work. Experimental Method: The apparatus and procedure were essentially the same as those used in the earlier investigation of the effect of silicon on sulphur activity.&apos; Briefly, the method was as follows: A molten iron-carbon alloy was brought to equilibrium at constant temperature with a mixture of H2 and H2S of constant composition by bubbling the gas through the metal. Samples of the melt were

Jan 1, 1951

By J. P. Nichols

Modern vibrating screening dates from about 1910 at which time the forerunner of the present day two bearing and four bearing circular motion inclined vibrating screens were first introduced. These simple machines consisted of a screen box holding some kind of a screening surface to which was attached an off-center shaft or a shaft with an off-center weight which was rotated. The rotation of these shafts caused a shivering motion to the screen box and produced the first vibrating screen. In the 1920&apos;s and early 30&apos;s, the box designs were improved and the mechanisms designs were also improved and by 1940, vibrating screens were an important part of most process plants. In the early days when the screen sizes were dictated by how much could be shoveled onto the screen box and by the force that a particular mechanism could produce, not much thought was given to the proper sizing of the particular units. As mechanism and body design improved the ability to predict vibrating screen capacity at various openings became more important. In the late 1930&apos;s, a set of empirical capacities came to be used. with few modifications, these capacities are still in use today, both by those companies that use a formula involving only the amount of fine material in a feed, and by those companies using a formula in which the total feed to a particular screen is used. In either method of calculation, the empirical values are based on these ideal conditions: (1) The material being fed to the screen contains 25% oversize. (2) The feed to the screen contains 40% half size material. (3) The material has a bulk density of 1.6 T/Cu.M. (100 lbs/cu.ft.). (4) The screening surface has an open area of 50%. (5) The material is dry, free flowing and relatively cubical. (6) The maximum screening efficiency required is between 90 and 95%. It is obvious that these conditions do not occur in natural or crushed size distributions. Therefore, modifications must be made to these empirical values to allow for the calculation of a vibrating screen for a particular set of conditions. Before we consider these various modifications, let us look at what happens to material as it is acted on by a vibrating screen so that we can better understand why the modifications are nec-

Jan 1, 1982

By R. P. Carreker

ONE of a series, this report is concerned with the experimental documentation of the deformation behavior of pure metals over a wide range of temperature. Previous reports in the series describe the creep behavior of platinum1 and aluminum2 and the tensile behavior of copper,&apos; silver,& and molybdenum.5 Subsequent reports will describe the creep behavior of copper and silver and the tensile behavior of platinum, thus providing extensive creep and tensile data on four face-centered-cubic metals tested under comparable conditions. Material Two lots of high-purity aluminum were used in this investigation. One lot, designated AC, was obtained direct from the Aluminum Co. of America as high-purity aluminum in notch-bar form. A typical analysis of this type of aluminum is 0.006 pct Si, 0.015 pct Cu, 0.006 pct Fe, and 99.975 pct Al. Lot BS was obtained from J. I. Hoffman of the Bureau of Standards as a portion of the Aluminum A described in his report of the redetermination of the atomic weight of aluminum.6 Lot BS originated with the Aluminum Co. of America also, and was received in the standard notch-bar form. A detailed chemical and spectroscopic analysis of lot BS has been published.6 Principa1 impurities were 0.006 pct Si, 0.003 pct Fe, 0.002 pct Cu, and >99.987 pct Al. Samples were processed identically by room-temperature swaging and drawing to 0.030 in. diam wires from approximately ½ in. diam rods that were machined from the notch-bar pigs. Samples were cut from the cold-drawn wire, placed in a grooved graphite block in groups of thirteen, and annealed in air for 1 hr at each of several temperatures, with the results shown in Table I. The two lots of aluminum responded quite differently to annealing, the behavior of aluminum AC suggesting that its grain growth was controlled by impurities. The recrystallization texture of aluminum of similar purity comparably treated has been reported as predominantly <111> fiber with some <100> fiber present.7 Testing Procedure The testing procedure and method of analyzing the data have been described previously.2,3 Annealed specimens of 5 in. gage length were tested in an Instron tensile testing machine at a constant head motion corresponding to a strain rate of 0.04 min-&apos; at a number of temperatures. Instantaneous tenfold rate changes were employed in some tests to deter-

Jan 1, 1958

By Charles W. Wagner

A premature explosion might be described as an explosion that, occurs before the miner expects it. Notwithstanding that it is unexpected, a premature is generally within the miner&apos;s control. A hangfire explosion is a blast that occurs after the miner expects it,, and in all instances, except where the explosives or blasting accessories are defective, hangfire explosions are within the miner&apos;s control. Causes of Premature Explosions Generally, there are seven methods of shot-firing in anthracit,e mines; namely: (1) cap and fuse with dynamite, (2) fuse with pellet powder, (3) squib with black powder or pellets, (4) exploders and delays with dynamite or black powder, (5) exploders with dynamite, (6) delay ignitors with black powder or pellets, (7) electric squibs with black powder or pellets. Cap and Fuse.—This method of firing seems to produce the greatest number of premature explosions. This is not solely because of the method, but is the result of mispractices which are possible with this method of firing. The two most common mispractices followed with cap-and-fuse blasting are the firing of multiple holes and the use of short fuse.. In the firing of multiple holes by cap and fuse, investigations have shown that in nearly every instance where the miner was injured by this method of firing he remained too long at the face lighting the several fuses, so that the first shot went off before he could reach a place of safety. Such accidents could have been avoided either by accurate judgment by the miner of the relative lengths of the fuses or by the use of electric firing. Rules exist in nearly every mine forbidding the lighting of more than one hole at a time where the cap-and-fuse method of firing is practiced. Where it is desirable to fire more than one hole at a, time, electric firing should be used. It is difficult to understand why so many premature explosions result from the use of short fuses, inasmuch as the cost of fuse is practically a negligible item in the expense of a day&apos;s work. Notwithstanding this, however, we frequently find miners using short lengths of fuse in an effort to save one or two cents per hole, or about 15 to 20 # in a day. A practice

Jan 1, 1931

By H. C. Otis

During the past year or two considerable time and money have been spent in developing equipment for tubing large-volume high-pressure oil and gas wells without loss of production. That the efforts have met with success is proved by the fact that any properly cased well, regardless of its production or regardless of its rock pressure or working pressure, can now be safely tubed with no appreciable loss of production, provided experienced crews handle the new equipment. It is conceded that a far better gas-oil ratio can be secured by flowing a well through tubing of a proper diameter—the diameter of the tubing depending, of course, upon the volume of fluid and gas and the depth of the well—than by the more usual method of installing a choke at the mouth of the well. Where possible it is becoming the practice to bring wells in through tubing, though in the majority of instances this is not feasible. In many instances it has developed, after a well has been brought in through tubing, that the tubing installed is either too large or too small for the most efficient operation or that the well had not been drilled deep enough. The equipment described in this paper, in the hands of experienced men, permits the tubing of these wells after they have been brought in, with the size of tubing then determined by actual observation to be best suited for each particular well, and with no danger of the well getting out of control, of catching fire, of drilling itself deeper, or of any loss of production. The deeper the flowing production with the consequent future higher lifting costs, the more essential it is that the size of tubing used be such as to give the best possible gas-oil ratio. The ability to bring in these deep wells through the casing and then, immediately after their completion, regardless of volume or pressure, to tube them with the size of tubing that permits the most efficient use of the gas present will doubtless save many dollars. Uses for the New Equipment The equipment permits a further step in the operation of wells where the conservation of gas is of major importance. Perhaps 3-in. tubing

Jan 1, 1930

Discussion of the paper of DORSEY HAGER, to be presented at the Colorado meeting, September, 1918, and printed in Bulletin No. 138, June, 191S, pp. 1109 to 1118. WALLACE E. PRATT, Wichita Falls, Tex. (written discussion*).¬Mr. Hager has touched upon interesting problems related to the broad subject with which he has entitled his paper. As to the existence of the important structural feature in the buried Bend series, which Mr. Hager constructs from well-logs, and designates as the "Bend Arch," there seems to be general agreement among a number of observers. Indeed, M. G. Cheney1 and Robt. T. Hill2 have each published structural maps of the Bend Arch that do not differ essentially from the map shown in Mr. Hager&apos;s Fig. 1. The reflection, in the overlying, unconformable Cretaceous, of certain folds in the Pennsylvanian, with which the petroleum accumulations has to do, is an important observation on the part of Mr. Hager, since, as he says, much critical territory is covered by Cretaceous, and it is highly desirable that the underlying Pennsylvanian structure be mapped, if possible. If the folds in the Pennsylvanian are of post-Cretaceous age, then it should be possible, in spite of the intervening unconformity, to determine approximately the position of buried folds beneath the Cretaceous overlap. The idea of post-Cretaceous folding would not be out of accord with the suggestion by Carroll H. Wegemann that the folding of the Permian beds in southern Oklahoma was still in progress as late as the Tertiary.3 But most observers have related the folds in the Pennsylvanian and Permian beds at the surface, both in North Texas and southern Oklahoma, to the process of. emergence of the land area at the end of the Permian. It seems more probable that the reflection of Pennsylvanian folds in the unconformable Cretaceous which Mr. Hager observed is due to long continued persistence of stresses which were largely relieved at the close of the Permian, than that the principal period of folding was post-Cre-taceous; this being the case, it seems likely that only folds of greatest intensity in the Pennsylvanian will, be decipherable in the Cretaceous overburden, and that many promising structural features are so concealed by the Cretaceous as to escape detection except by drilling.

Jan 8, 1918

By H. C. George

Since 1911, when J. L. Dunn first used compressed air for repressuring depleted oil sands in southeast Ohio, the rejuvenation of many depleted oil fields has been directly due to repressuring by means of air or gas. Developments in repressuring in recent years have resulted in its successful use in the early life of some deep, high-pressure oil fields, conserving the natural gas dissolved in and associated with the oil by returning it to the producing oil sand after it has been compressed above the existing rock pressure of the reservoir. One of the most successful operations of this type is that of the Humble Oil & Refining Co., on the DeWalt salt dome at Sugarland, Texas. I quote from a personal communication with reference to this field: "Structurally, the field is dome-shaped, having a closure of approximately 350 ft. Production comes from a sandy shale interbedded with a clean sand and lying over a cap rock which is about 3400 ft. deep on top of the structure." A feature of the operation of this field is the production of the required amount of oil with the minimum of gas production. Wells on top of the dome have high gas-oil ratios, while those down structure have lower ratios, depending upon the distance of the well from the peak. To date, it has been possible to produce the oil needed from the wells circling the dome above the water zone and below the gas zone, and in this manner the average gas-oil ratio has been kept low. The gas from all separators is turned into a gas system which serves the entire field. From this system, all drilling rigs and utilities requiring gas for a fuel draw their requirements, and the remainder of the gas (about two-thirds of the production) is delivered to a compressor plant which boosts the pressure until it can be returned to the sand at the top of the dome where the rock pressure is 1400 lb, per square inch. "The Sugarland wells produce through 2-in. tubing with a 3/8-in. choke in one wing of the well-head manifold. The pressure builds up as high as 1300 lb, per square inch on the casing while on the tubing it varies from 0 to 900 lb. per square inch, depending upon the amount of gas produced with the oil."

Jan 1, 1931

By Will Mitchell, T. G. Kirkland, C. L. Sollenberger

R. S. Handy (Santa Rosa, Calif.)—It would be interesting to learn the comparative results of treating the Korean scheelite ore described in this paper according to the following procedure: I—Follow the procedure described in the paper to the recovery of the sulphides by flotation. 2—Dilute the residue from the sulphide flotation strongly with water and disperse the contained colloids by adding a mixture of 75 pct sodium silicate and 25 pct quebracho to dispersion point. 3— Settle the dispersed pulp and decant the supernatant colloids. 4—-Dilute, settle, and decant the pulp until the settled residue is crystalline. Not over 10 pct of the tungsten minerals should follow the colloids. 5—Treat the settled residue by flotation, having established the proper pH. Oleic acid homogenized with cresylic acid or kerosene is more selective for scheelite than is oleic acid alone. (The recovery of the contained tungsten minerals should be practically complete in this operation.) 6—Deflocculate the tungsten concentrate from step 5 with the same dispersion agents as in step 2 and treat the deflocculated pulp by gravity. The minerals that tend to float with scheelite are generally of low specific gravity and the separation is efficient. The heavier contaminants, such as pyrrhotite and magnetite can be removed magnetically, leaving a practically pure scheelite. E. J. Pryor (Imperial College of Science and Technology, London)—It occurred to me that instead of using temperature as a differentiating control, more precision might be obtained with a reagent of a type we developed here for the flotation of high grade fluorspar in cold pulps. This reagent, which is manufactured on a modest scale in England, is based on oleic acid, which has been modified by our patented process to ensure complete stable dispersion at any desired concentration in water. It thus becomes possible to utilise unimolecular layers with good selectivity. In the fluorspar flotation for which we developed it, it is possible to hold a tight control on depressing quebracho for the calcite without substantial loss of flu-orite, and recovery exceeding 99 pct is not uncommon in the mill where it is in use, even under wintry conditions. No attempt has been made yet to extend the use of the reagent, as we have not completely overcome

Jan 1, 1952

By J. R. Campbell

In order to discuss the subject intelligently, it will be necessary to touch briefly on the forms in which sulphur is supposed to exist in coking coal to be carbonized in beehive or byproduct ovens. Sulphur is known to exist in coal as sulphides and sulphates, as can be determined experimentally. Then there is the so-called organic sulphur, i.e., sulphur in combination with the carbon, &apos;hydrogen, and oxygen of the coal, about which much has been written, but nothing definitely proven in an experimental way. In fact, so far. as we know, there never has been developed a satisfactory and conclusive method in the laboratory for the direct determination of organic sulphur. For most coking coals, it can be safely assumed that the preponderance of sulphur is in the form of pyrite (FeSz). When exposed to comparatively low temperatures during the coking process, it loses its sulphur according to the following chemical reaction: 7FeS2 = Fe7Ss + 6S. It will be seen, therefore, that six out of the 14 atoms of sulphur (or 42.8 per cent.) are expelled, or volatilized. FelSa remains in the coke as pyrrhotite, or magnetic sulphide of iron; this accounts for the highly magnetic properties of the powdered coke. A more commonly accepted reaction is FeS2 = FeS f S, in which the straight sulphide of iron is produced with 50 per cent. volatilization of sulphur. In the beehive methods of coke making, air is introduced in sufficient amounts to carry on the distilling and the coking processes, and the sulphur is oxidized along with the other volatile products: First, into sulphur dioxide (SO2), known by the pungent andsuffocating odoremitted from the trunnel head; second, into sulphuric anhydride (SOa); and, finally, into sulphuric acid, as it comes into contact with the air and moisture. In a properly regulated draft on a beehive oven, there is never complete combustion of the gases. In other words, the coking process should be carried on in a reducing atmosphere, and a low-grade producer gas kept issuing from the trunnel head. For coals of about 30 per cent. volatile matter, the ratio of air to gas is 3½ to 1. In complete combustion, the ratio is 6 to 1, producing an extremely high temperature

Jan 1, 1916

By F. L. Bosqui

Discussion of the paper of F. L. Bosqui, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 101, May, 1915, pp. 997 to 1033. H. A. WHITE, Springs, Transvaal (communication to the Secretary*). -It is, as the author points out in his valuable paper, a, fact, that in many plants the "trommel washings" are allowed to become eyesores, but the simpler system of pumping the entire product direct to the tube-mill circuit will avoid the extra expense of separation and small-scale treatment when one considers the relative distance of the points and the proportionately small amount of water. It is a matter of record that in stamp batteries the increase of weight has been developed concurrently with the increased use of tube mills, but independently and on its own merits. The satisfactory duty, excellent running time, and freedom from breakages in the newer mills, such as the Modder Deep, with 2,000-1b. stamps, will probably go far in removing some of the conservative prejudices mentioned by Mr. Bosqui. The success of the City Deep trial of the Nissen stamp cannot be entirely attributed to better feed distribution and discharge effects (published experiments on two-face discharge mortar boxes showed no advantages). Attention is directed to the treatment costs given by the author both before and after the increased capacity resulting from the addition of 16 Nissen stamps at Modder B. It will be observed that the only item of cost resisting the tendency to reduction caused by increased tonnage is that of milling, which has risen 1.3c. With reference to the provision for amalgamation in the new plans, it seems obvious that a great loss of head would be eliminated by passing the tube cone overflow over a separate top series of plates; three at the top and three at the bottom will effect the maximum amalgamation. This plan is followed at the Princess Estate and Gold Mining Co., Ltd., Modderfontein Deep Levels, Ltd., and Geduld Proprietary. Mines, Ltd., but elsewhere reliance is placed upon ample cone capacity and the underflow only is passed over three plates after going through the tube mill, while the overflow is passed direct to the cyanide works; both methods avoid the largely unnecessary elevation of considerable quantities of water, fine sand and slime involved in Mr. Bosqui&apos;s scheme.

Jan 1, 1916

By C. E. Birchenall, H. M. Schadel

THE purpose of this study was to measure the vapor pressure of silver as the first step in the determination of activities in silver alloys and to test the limitations of the method adopted. In order to work at low pressures, below 2x10-2 mm of mercury, the orifice effusion technique was employed. To shorten the time of collection of silver from the atomic beam, radioactive silver (Ag110) was used as a tracer. The rate of effusion of a monatomic vapor from an "ideal" orifice, where the thickness of the orifice edge is negligible compared with the orifice diameter, can be readily calculated from the kinetic theory of gases, G = vM a p/v2pRT where G is the weight of material effusing from the orifice per unit time; p is the vapor pressure at oven temperature, T; R is the gas constant; M is the molecular weight of the vapor; and a is the orifice area. Consolidating constants and expressing as the weight of material effusing from the orifice in a period of time, t, (5.83)(10-2) (vM) (a) (t) (p)/vT where GT is total weight of monatomic vapor effused (g); M is molecular weight of the effusing tracer vapor; a is orifice area (cm2); t is time of effusion (sec); p is vapor pressure of effusing material (mm of Hg); and T is oven temperature (OK). The vapor effuses from the orifice in a hemispherical pattern, and the intensity of the beam in any direction is given by the cosine distribution law.&apos; Considering this, the weight of effused material can be calculated from the amount of material passing through a circular collimator intersecting the beam. If such a collimator is in a plane parallel to the plane of the orifice and with center on the normal to the orifice center, GT = G?/1-cos2? = G?/sin2? where G? is the weight of effused material passing through the collimator, and 0 is one half the apex angle of the cone defined by the collimator circumference and the orifice center. Reducing eq 3 to the more directly measurable quantities of orifice to collimator distance, d, and collimator diameter, D, the expression becomes,

Jan 1, 1951

By Dr. O’Neil Thomas J., Donald W. Gentry

Introduction “A Western mine is a hole in the ground owned by a liar. . ." -Mark Twain THE CAPITAL INVESTMENT DECISION Decisions pertaining to a firm&apos;s proposed capital investments can have vital short- and long-term consequences on the organization&apos;s ability to compete, and even survive.Capita1 investment decisions, in general, center around two fundamental activities: (1) allocating capital funds to specific investment projects or assets, and (2) obtaining necessary financing in such proportion as to increase the overall value of the firm. In essence these activities or decisions describe the science of finance (as contrasted with economics). Fimnce has been described in general terms as the study of how a present, known amount of cash is converted into a future, perhaps unknown, amount of cash (Archer, Choate, and Racette, 1979). Fundamental to understanding the science of finance and the capital investment decision process in general are the basic concepts relating to cash flow transactions, time, income generation (markets), expected returns, and risk. The functions of finance may be segregated into three fundamental decisions which a firm must address: (1) the dividend decision, (2) the financing decision, and (3) the investment decision. These decisions are interdependent and their joint impact on the objective of the firm must be considered. This book primarily addresses the concepts and components associated with the investment and financing decisions as they affect the practice of mine valuation. Responsibilities of Management A primary assumption incorporated in this book is that the fundamental objective of any firm is to maximize its value, or wealth of its owners (stock- holders). Here, the term wealth refers to the total current market value of the firm&apos;s assets. In the case of corporations, the wealth or value is considered to be represented by the market price of the firm&apos;s common stock. The price of the firm&apos;s common stock obviously will be affected by its investment, financing, and dividend decisions. Consequently, an optimal combination of these three decisions should maximize the value of the firm to its stockholders. It is important to point out that wealth maximization is a more appropriate and inclusive goal for the firm than profit maximization. Indeed, there is a difference between the two objectives in most situations. For instance, a firm can always raise profits by selling stock and investing the proceeds in treasury bills or certificates of deposit. This type of activity, however, would rarely cause net shareholder wealth

Jan 1, 1984

By D. H. Davis

HAND picking was the earliest form of coal preparation, first practiced to improve the outward appearance of the coal being loaded and to remove any pieces that might appear objection- able to the buyer. It is still extensively practiced on the plus 1-in. sizes and particularly on the plus 4-in. and larger sizes. The percentage of ash reduction that can be obtained by hand picking depends entirely upon the amount of free impurity occurring in the coal. In a particularly dirty seam, where a considerable quantity of rock occurs with the coal as mined, hand picking produces sizable reductions in ash. If the coal is prepared clean at the working face hand picking is a final check; in some cases, on the smaller sizes, it is practiced only to show that an effort is being made to prepare a clean product. Because of the variety and different methods of handling coal, the early plants were not always adapted for efficient hand picking. At most mines an attempt is made to remove the visual impurities at one or more of the following places in the surface plant? (1) in the tipple during screening; (a) on picking band, belt, or shaking conveyors;*(3) during the loading of the coal as it goes into the railroad car. Whatever the physical arrangements of the plant may be, the usual practice is to run the coal over the screen, picking table or boom at such a rate that each piece of impurity is exposed to the view of the picker. Coal should be uniformly sized and spread out on the table so as not to exceed one particle in depth. The flow should be even in tonnage and the speed of travel should be from 30 to 60 ft. per minute and not exceed 80 ft. per minute. The dirtier the coal, the slower the speed required for a fixed number of pickers. Actually, picking capacity depends on the number of particles per minute that can be picked out and rejected. The percentage of impurity removed is determined by this and the average weight of piece rejected. Handling a mixture of sizes from nut to the largest lump over the same picking table or conveyor is not conducive to efficient separation by hand picking because the lump hides the smaller

Jan 1, 1943

By R. H. Olds, B. H. Sage

The formation volume and volume of the liquid phase of oil and gas obtained from four fields in the San Joaquin Valley have been investigated at pressures, temperature, and gas-oil ratios comparable to those encountered in underground reservoirs. All the fields covered in this investigation yielded a product of a gas-oil ratio in excess of 5000 cu ft per barrel and the gravity of the tank oil for the four fields in question varied between 52° and 63&apos; API. The results of the investigation, together with analytical data concerning the composition of the oil and gas, are submitted in tabular form. Rough correlations of the formation volume as a function of pressure, temperature, and gas-oil ratio and of the retrograde dew-point pressure as a function of gas-oil ratio, temperature, and gravity of tank oil are presented. It was not found feasible to correlate simply the formation volume of the liquid phase as a function of the applicable variable. It is desired to emphasize that these correlations are considered applicable only to the range of conditions covered in this investigation and for systems of similar nature and composition. Introduction Information concerning the physical properties of mixtures of oil and gas from particular fields have often been employed in predicting the situations obtaining in underground reservoirs. One of the earlier studies of this nature was the work of Beecher and Parkhurst,1 while a more recent study of the Dominguez Field2 presented detailed volumetric data in the two-phase as well as in the single-phase regions. Although these studies were confined to individual fields, their results proved of value in application to other fields. It has recently been shown 3,4 that it is possible in the region of low gas-oil ratios* to correlate the volumetric behavior of naturally occurring hydrocarbon mixtures from a single geographical area with sufficient accuracy to be of industrial value. For this reason it is considered of interest to submit information concerning the volumetric behavior of oil and gas mixtures from four different fields in the San Joaquin Valley and, in combination with similar published data5 concerning mixtures of oil and gas from the Paloma field in the same area, to show rough correlations between the composition and the behavior of materials from these fields. This effort seems particularly worth while since all of the

Jan 1, 1947

By R. H. Olds, B. H. Sage

The formation volume and volume of the liquid phase of oil and gas obtained from four fields in the San Joaquin Valley have been investigated at pressures, temperature, and gas-oil ratios comparable to those encountered in underground reservoirs. All the fields covered in this investigation yielded a product of a gas-oil ratio in excess of 5000 cu ft per barrel and the gravity of the tank oil for the four fields in question varied between 52° and 63&apos; API. The results of the investigation, together with analytical data concerning the composition of the oil and gas, are submitted in tabular form. Rough correlations of the formation volume as a function of pressure, temperature, and gas-oil ratio and of the retrograde dew-point pressure as a function of gas-oil ratio, temperature, and gravity of tank oil are presented. It was not found feasible to correlate simply the formation volume of the liquid phase as a function of the applicable variable. It is desired to emphasize that these correlations are considered applicable only to the range of conditions covered in this investigation and for systems of similar nature and composition. Introduction Information concerning the physical properties of mixtures of oil and gas from particular fields have often been employed in predicting the situations obtaining in underground reservoirs. One of the earlier studies of this nature was the work of Beecher and Parkhurst,1 while a more recent study of the Dominguez Field2 presented detailed volumetric data in the two-phase as well as in the single-phase regions. Although these studies were confined to individual fields, their results proved of value in application to other fields. It has recently been shown 3,4 that it is possible in the region of low gas-oil ratios* to correlate the volumetric behavior of naturally occurring hydrocarbon mixtures from a single geographical area with sufficient accuracy to be of industrial value. For this reason it is considered of interest to submit information concerning the volumetric behavior of oil and gas mixtures from four different fields in the San Joaquin Valley and, in combination with similar published data5 concerning mixtures of oil and gas from the Paloma field in the same area, to show rough correlations between the composition and the behavior of materials from these fields. This effort seems particularly worth while since all of the

Jan 1, 1947

By E. W. Krampert

The oil industry was very active in Wyoming in 1936, in contrast to the several quiet years preceding. Production for the year again increased about 7 per cent, following an 8 per cent increase in 1935. During the year, 85 oil wells were completed, compared to 55 in 1935. Three gas wells were completed in 1936, and three in 1935. At the end of the year 45 wells were drilling, as compared to 55 drilling at the end of 1935. Two new oil fields and one new gas field were discovered in Wyoming during the year. In the year 1936 Wyoming produced 14,475,431 bbl. of oil, a gain of 1,001,081 bbl. over the 1935 figure of 13,474,350. This increase, in the main, was due to the taking of light oil from the newly developed Sundance sand pool at Lance Creek, and from the new fields, Quealy and Medicine Bow, which contributed their first production this year. Most of the other old fields either were partly shut in in competition with the new fields, or showed a normal decline. This was especially noticeable in the black-oil fields, where production had been slowly but steadily increasing for a number of years. During 1936 black-oil production decreased approximately 100,000 bbl. as compared to 1935. The only black-oil field to show marked increase was Garland, which managed to take the market from less favorably located fields. The production of Wyoming in 1936 was 11,358,757 bbl. of light oil and 3,116,674 bbl. of black oil. Salt Creek, with a production of 6,015,000 bbl., is still the largest single oil-producing field, accounting for 42 per cent of the year&apos;s total production. Lance Creek, an old field, with newly developed production in the Sundance sand, reached second place this year for the first time in its history, with a production of 1,878,486 bbl. Lance Creek production will almost equal that of Salt Creek in 1937, if the present rate of production is maintained during the coming year. Oregon Basin, a large black-oil field, held second place in 1935, but owing to a greatly lessened demand for its production, dropped back to third place in 1936. This was in part due to greatly increased light oil available, and in part to the greater supply of black oil available at

Jan 1, 1937

By Bailey Willis

IN 1882, Peckham put forward a provisional hypothesis to account .or the distillation of petroleum.1 He did not formally state the hypothesis, but in a discussion of facts drawn from many fields he made it clear that he regarded petroleum, and especially the petroleum of the Pennsylvania fields, as a "fractional distillate produced under high pressure and consequently at a comparatively high temperature.?2 He quotes James Hall on the geology of the Appalachians and says:3 It is not necessary here to discuss the nature or origin of metamorphic action. It is sufficient for our purpose to know that from the upper Silurian to the close of the Carboniferous periods the currents of the primeval ocean were transporting sediments, sorting them into gravel, sand, and clay, forming gravel bars and great sand beds beneath the riffles and clay banks in still water, burying vast accumulations of sea weeds and sea animals far beneath the surface. The alteration, due to the combined action of heat, steam, and pressure, of the formations of the Appalachian system from Point Gaspe in Canada to Lookout mountain in Tennessee, involving the Carboniferous and earlier strata, distorting and folding them, and converting the coal into anthracite and the clays into schists along their eastern border, could not have ceased to act westward along an arbitrary line, but must have gradually died out farther and farther from the surface (source?). The great beds of shale and limestone containing fucoids, animal remains, and even indigenous petroleum must have been invaded by this heat action to a greater or less degree, and that "chronic evaporation" of Prof. Lesley must have been the inevitable consequence. From an investigation of the relations between coal and petroleum, White has" more recently concluded as follows: (1) Petroleum is a product generated in the course of the geodynamic alteration of deposits of organic debris of certain types buried in the sedimentary strata. (2) The quantity and characters of the oils generated are determined by: (a) the composition of the organic deposit at the beginning of its dynamo-chemical alteration; (b) by the stage in the progress of the dynamo-chemical alteration of the organic substances; (c) by the elimination, under certain conditions, of the heavier and more&apos; viscous hydrocarbons through filtration incident to migration.

Jan 1, 1920