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By Ernest P. Hall

At the SME Fall Meeting held in Phoenix, Ariz. last October, Ernest P. Hall, addressing an Air and Water Pollution session, noted that water pollution caused by acid drainage from bituminous coal measures had begun long before recorded history. "Until recently," he said, "man did not begin to understand the physical phenomena which took place to cause [it] and even today he does not know what can be done to prevent it." CAUSES "It is known from the reports of early explorers that drainage from bituminous coal measures was causing water pollution before coal mines were opened on this continent. They noted the nature of the polluted water in the runs and creeks and predicted the presence of substantial deposits of coal based on the appearance and character of the water. Even today, polluted water drains from virgin coal areas which have not been touched by mining machines," Mr. Hall said.

Jan 1, 1966

By D. E. Pickett, E. G. Joe

In accordance with good industrial practice, Canadian metallic-ore concentration plants have always recycled a high proportion of process water to save reagents, save power, conserve water resources, and to protect the community water supplies, to give only a few reasons. In the last few years there has been awakened public concern for the environment and, consequently, government regulations have been added as additional reasons. Present recycling practices are summarized as a basis for improved plant design and operating procedures and for further research. In addition, an attempt is made to determine why plants do not recycle water in certain situations. Although not all Canadian mills are covered, the many examples given indicate the problems and the effort being made to solve them. Wherever available, the chemical quality of the water and the process requirements are indicated as well as the other parameters affecting water recycling at each operation.

Jan 1, 1975

By G. B. Craig, B. Ramaswami

The temperature and strain rate dependence of the flow stress ratio and the stvain rate dependence qi the flow stress of annealed polycrystalline a zirconiur were determined over the temperature range 30 0" to 1000°K. Some evidence was found for strain aging and discontinuous flow in the temperature ranges 520" to 650°Kand650" to 760°K, respectively. The Cottvell-Stokes relationship was obtained when deformation occurred by twinning as well as slip. The flow stress ratio showed a strong dependence on temperature and strain rate above 800°K. The expevirnental evidence indicated that the rate-controllitzg mechanism for the deformation of a zirconium above 800°K was dislocation climb, and that the deformation was not thermally activated in the range 520" to 800°K. The stacking-fault energy of a zirconium was estimated to be about 250 ergs per sq cm. A knowledge of the temperature and strain rate dependence of the applied stress necessary to deform a crystalline solid is essential for understanding the thermally activated processes occurring during deformation.' Several experimental techniques have been developed for studying these processes.273 One of the techniques is the deter mi nation of the strain rate dependence of the flow stress at constant temperature. In close-packed crystals, it has often been observed that the change in stress due to a change in the strain rate varies linearly with the flow stress, (~1,' This relationship, known as the Cottre ll-Stokes law, is obeyed when deformation occurs by glide alone. However, when deformation occurs by twinning as well as glide, there is disagreement among different investigators on whether the Cottrell-Stokes law is observed. Whereas Thornton et ~1.~find departures from Cottrell-Stokes law when twinning occurs in copper, ~avis~ and sasinski? find that Cottrell-Stokes law is obeyed when deformation occurs by twinning as well as slip in cadmium and magnesium, respectively. One of the main objectives of this study is to determine whether the Cottrell-Stokes law is obeyed when deformation occurs by twinning as well as slip. The second technique that has been used extensively to study the thermally activated deformation of crystals is the determination of the ratio of the flow stresses, at identical dislocation structures and con-

Jan 1, 1968

By Henry A. Stiff, and Lawrence E. Davis

The authors previously presented a method for predicting the tendency of oil field waters to deposit calcium sulfate. The present paper gives a similar method for calcium carbonate. Methods for predicting calcium carbonate scaling tendencies in fresh waters have been available for some time, but these could not be used for brines. By experimentally deriving the value of the K term in the Langelier equation, a method has been developed which applies to waters of high salt content. A statistical study is included which shows that the experimentally derived values of K are in good agreement with actual conditions. Several applications of the final equation to production practice are given. INTRODUCTION The authors previously presented a method for predicting the formation of calcium sulfate scale in oil field waters.' Although calcium sulfate deposition is important in production operations, the majority of scale problems involve calcium carbonate. The present communication discusses a method by which the formation of this type of scale in oil field waters can be predicted. Calcium carbonate precipitation is caused by a shift toward carbonate in the carbonate-bicarbonate-carbon dioxide equilibrium. When equilibrium shifts in the other direction, the precipitate goes back into solution. Since there is usually considerable delay between the establishment of an equilibrium and the precipitation or solution of calcium carbonate, unstable conditions exist in which a water will precipitate or dissolve calcium carbonate on standing. Tillmans? who did a major part of the early work on carbonate scaling, pointed out that the condition of equilibrium not only indicates the tendency of a water to scale but also is an indication of its corrosive properties. Previously precipitated calcium carbonate combines with iron to form a dense crust which inhibits corrosion. If the water tends to dissolve carbonate, the scale becomes porous, and electrolytic corrosion takes place. Tillmans1 work was extended by several investigators until in 1934 Langeliers developed an equation setting forth the conditions of carbonate equilibrium. By the use of this equation the pH of a water at equilibrium can be calculated. If the actual pH is higher than the calculated pH, the water has a tendency to form scale. If it is lower. the water has a tendency to be corrosive. Langelier's equation can be expressed in a simple form as follows: SI = pH-pCa-pA lk-K where: SI is the stability index. A positive index indicates scale formation. A negative index indicates corrosion. pH is the pH of the water sample, as actually determined. pCa is the negative logarithm of the calcium concentration. pAlk is the negative logarithm of the total alkalinity. K is a constant, the value of which depends on the total salt concentration and the temperature. This equation has been shown to apply to waters with totaI solid concentrations as high as 4.000 ppm. In fact, control of fresh water treatment by means of this equation has been standard text-book practice for a number of years. Nomographs have been worked out so that the stability index of a fresh water sample can be determined in a matter of minutes. Most oil field waters, however, contain well over 4,000 ppm of salts and for this reason the usual application of Langelier's equation can not be made. By an empirical method we have extended the application of the Langelier equation to waters of high salt concentration. By the use of this equation the tendency of oil field waters to deposit calcium carbonate can be predicted.

Jan 1, 1952

Jan 1, 1954

Jan 1, 1936

By Charles P. Williams

THE successful production of zinc white or oxide on a commercial scale in this country dates from the issue of the patent of Samuel Wetherill, for the preparation of the material (November, 1855), and

Jan 1, 1877

Jan 1, 1968

By Charles P. Williams

The successful production of zinc white or oxide on a commercial scale in this country dates from the issue of the patent of Samuel Wetherill, for the preparation of the material (November, 1855), and

Jan 1, 1915

By Frederick T. Williams

THE purpose of this paper is to discuss the relative merits of the large 31/8 in. machine and the small 21/4-in. tappett machine in driving development-headings ; and although the . data here presented were obtained from cross-cut headings alone, experience has shown that the results are equally true in drifting, raising and winning. Recently we drove two parallel cross-cuts through the same formation, using a 3k-in. machine at the breast of one cross-cut., and a 2k-in. machine of the same make at the breast of the other. The results of this work afforded an ideal comparison, since in both cases the headings were advanced through rock practically of the same hardness and breaking-properties ; the amount of sludging was equal, and there was no difference in the condition of the steel or the machines, in the air-pressure or in the experience of the operating-crews. Some operators in the Cripple Creek district contend that there is ground which cannot be handled with the small machine, the holes being too small to contain enough powder to pull the ground, etc. The results obtained in working the property of the Portland Gold Mining Co., however, show that the ground worked by them does not fall in this class. During a period of two years there have been driven, with the small machine, 4 miles and 308 ft. of development-headings, through a diversity of ground, including Pike's Peak granite (a coarsely porphyritic type of granite), highly indurated, andesitic or phonolytic breccia, true massive andesite, trachytic phonolyte, tuffas, and along dikes of decomposed basalt and hard phonolyte; in every instance a satisfactory record was made. The headings here described were driven through highly indurated, andesitic breccia, having a hardness of from 5.2 to 7.2

Mar 1, 1906

By C. R. Van Hise

Introduction.............29 The Three Zones of the Lithosphere ..30 Zone of fracture............31 Zone of flowage............ 31 Factors influencing depth at which flowage occurs.. 32 Zone of combined fracture and flowage.. 33 The Water-Content and Openings in Rocks....36 Condition of rater in the zone of fracture.. 36 The openings in rocks...........38 Size and number of openings..... 40 Ore-deposits derived from zone of fracture..45 The source of underground water......... . 47 The cause of the flowage of underground water..47 Belts of underground circulation.. 51 Upper belt of underground circulation.. 51 Lower belt of underground circulation.. .... .52 Capacity of water for work in the lower belt of underground circulation........... 53 Movementsof water in the lower belt of underground circulation. 54 The preferential use by water of large channels.. 60 Physico-Chemical Principles Controlling the Work of Under ground Waters..........62 Chemical action............63 Underground aqueous solutions..64 The relations of solution and temperature..... 65 The relations of solution and pressure..66 Precipitation........... 67 Precipitation by change in temperature..68 Precipitation by change in pressure..69 Precipitation by reactions between aqueous solutions.. . 69 Precipitation by reactions between liquid solutions and solids. 70 Precipitation by reactions between gases and solutions. and solids............71 The General Geological work of Underground Waters.. . 71 Division of the zone of fracture into a belt of weathering and a belt of cementation............72

Jan 1, 1901

By W. W. Svendsen, J. F. Hoffmeister, W. C. Larson, R. E. Cozad

The paper presents the background, history, and current development of the retractable core bit for the wireline drilling system. Design criteria, concept development, and system design of the retractable bit system are discussed, including laboratory test results.

Jan 1, 1983

By Hamilton Wingate

In his paper on the hydraulic mining of a low-grade gravel in California,* Mr. W. H. Radford expresses the hope that other members of the Institute will contribute, for the benefit of all, their experience in similar lines. In these notes 1 shall describe the conditions and results of the operation of the Gold Bug Mining Co., of Cleveland, O., at Georgetown, Eldorado county, Cal.

Jan 1, 1903

By Roy C. Kirkman

It is with great pleasure that I read Mr. Howard M. Wells article in the December 1978 issue of MINING ENGINEERING entitled: "Optimization of Mining Engineering Design in Mineral Valuation." Mr. Wells very adequately presents the case and point that there are a great number of variables which must be analyzed during an economic evaluation of an FUND RESOURCE, such as copper or uranium.

Jan 4, 1979

By H. H. Klepfer, K. J. Gill, P. Chiotti

SOME observations relative to the U-Zn system have been made by other investigators. Chipman1 and Carter2 have reported the preparation of several U-Zn alloys and point out that these alloys are generally difficult to prepare. Chipman1 reported evidence for a high melting compound at about 90 atomic pct Zn and the possible existence of a eutec-tic between the compound and uranium. Raynor," in a theoretical discussion of the alloying properties of uranium, included zinc among the elements predicted to have little or no solubility in a, p, or y uranium. In the present investigation, thermal analyses, X-ray, metallographic, and vapor-pressure data were obtained to determine the phase boundaries. The relatively high zinc pressure over most of the alloys at temperatures of 900 °C and above proved troublesome and special techniques had to be employed in preparing suitable alloys. Materials and Preparation of Alloys The metals employed in this investigation were Ames Laboratory biscuit uranium containing less than 500 ppm total impurities and Bunker Hill slab zinc or Baker Analyzed reagent granulated zinc, both with a purity of 99.99+ pct. Due to the high vapor pressure of zinc and the high reactivity of both uranium and zinc with oxygen at only moderately high temperatures, alloys were prepared in closed containers which had either been evacuated or evacuated and filled with helium. High purity magnesia, magnesia containing 10 pct calcium fluoride, and tantalum proved to be suitable crucible materials. Tw-o different procedures, described below, were used to prepare alloys, the latter being the most satisfactory. The metals, uranium turnings and granulated zinc, were cleaned with dilute nitric acid, rinsed, dried, and placed immediately in a helium-fill'ed dry box. The two metals were placed' in a 10 mil Ta crucible. The charge was enclosed in the tantalum crucible by welding on a preformed tantalum cap. This assembly was enclosed inside a stainless steel (AISI 309) bomb. The bomb was made by welding a piece of stainless steel plate on each end of a stainless steel pipe. All these operations were carried out in a helium atmosphere. These assemblies were heated in a muffle furnace at temperatures between 1100" and 1200°C for 10 to 15 min or held as long as 15 to 20 hr in the 950" to 1000°C temperature range before quenching. Spectrographic and chemical analyses showed no tantalum pickup by the alloys, indicating no reaction between the alloys and the crucibles. However, some of these crucibles failed, probably due to imperfections in the welds of the stainless steel or tantalum crucibles. The second and most satisfactory method was to prepare the alloys by powder metallurgy techniques. The procedure was to press degreased and acid-etched uranium turnings with granulated zinc into 20 g compacts under 20,000-psi pressure. The compacts were placed in MgO crucibles, and sealed in evacuated Vycor or fused silica tubes. The alloys were then heated as long as two weeks at about 550°C in a muffle furnace. The pressed compacts were observed to expand by several volume percent during heating and it was necessary to make allowances for this expansion in order to avoid breaking the crucible and Vycor tube. This method was found very satisfactory for preparing alloys which were suitable for thermal analysis or vapor pressure studies. Experimental Methods and Results The phase diagram for the U-Zn system at 1 atrn pressure, shown in Fig. 1, is based primarily on vapor pressure measurements and on thermal analysis taken at temperatures below 950°C. Fig. 2 shows the U-Zn diagram at 5 atrn pressure, constructed on the basis of thermal analysis of alloys in sealed containers up to 1150°C and on the basis of metallographic, X-ray, and analytical data. The alloys sealed under vacuum were actually under their own vapor pressure and those sealed in an atmosphere of helium were under an additional pressure due to the helium. At temperatures up to 1100°C the zinc pressure is 5 atrn or less for these alloys; consequently the maximum pressure over the alloys sealed under a helium atmosphere was 10 atrn or less at temperatures up to 1100°C. Changes in pressure of this order of magnitude do not appreciably alter the position of most solid-solid or liquid-solid phase boundaries. In constructing the phase diagram for a pressure of 5 atm, the effect of pressure on all phase boundaries except those for liquid-vapor or solid-vapor regions was considered negligible.

Jan 1, 1958

Jan 1, 1888

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Jan 1, 1938

By F. Brons, V. E. Marting

In the past, other authors.1, 2 have studied the influence of a skin effect on the productivity of a well. This skin effect, expressed by the skin factor S, is considered to be caused by a thin layer of impaired permeability immediately around the wellbore and extending vertically over the whole productive interval penetrated by the well. The skin factor S is defined as follows. Based on this, the impairment in productivity caused by a skin can be expressed by the fractional loss in productivity I, which is the loss in productivity divided by the total unimpaired productivity. For compressible flow in a stabilized well which drains a circular area of radius re, 1 is given by The present paper deals with a different kind of productivity impairment. Consider a well in which part of the productive formation is blocked off completely, either by incomplete penetration or by exclusion of parts of the productive zone by blank casing. In Fig. 1 (A, B and C), three examples are shown. Fig. 1(A) shows the situation where a well only partially penetrates the formation. This often is done to combat the actual or imagined danger of bottom-water coning. Fig. 1(B) shows a well producing from only the central portion of a productive interval. This type of completion is sometimes used where both water and gas coning are a problem. Although the case of a well producing through perforated casing cannot be treated in a manner similar to the previous two cases (where radial flow in the horizontal plane is assumed), Fig. 1(C) shows several intervals open to production and qualitatively describes this case (as will be discussed later). To study the loss in productivity in all these cases, two parameters are introduced which fully determine the impairment. The first is the penetration ratio "b," i.e., the total interval open to fluid entry divided by the total thickness of the productive zone. The second is the ratio hlrw. In this ratio, rw is the wellbore radius. The definition of h is more cumbersome. In Fig. 1(A), h is the thickness of the total productive interval. The streamline configuration for this case of partial penetration is basic to the other two cases considered (Views B and C of Fig. 1). It will be obvious from Fig. i (A) that the flow lines in the uppermost portion of the formation will be essentially horizontal, while those in the lower portion will curve upward toward the well. In Fig. 1(B), with only the middle portion of the zone open to production, the streamline configuration. of the upper half will be an exact mirror image of that in the lower half of the zone. Hence, for the case illustrated in Fig. 1(B), h is defined as one-half the total sand thickness. It follows, then, that in Fig. 1(C) h is one-half the distance between corresponding points in adjacent intervals. (In gun-perforated casing, h would be one-half the distance between perforations.) In a paper by Nisle4 and a paper given by the present authors5, the mathematical theory was developed for the cases under consideration. In the present publication, the emphasis is put on the results of these studies; consequently, the equations derived in Refs. 4 and 5 will be omitted, for the most part. The pressure drop p in a well producing from only a portion of the total formation thickness can, in analogy with Eq. 1, be expressed by Numerical solution of Eq. 5 by use of the IBM 650 leads to the following important conclusions. First, during a short period after starting production (usually on the order of a few minutes), the function p(b) is given by

By P. M. Aziz, I. Markson, C. S. Barrett

The abnormal after-effect in twisted wires that occurs when untwisting is interrupted by etching con be brought under control and used to study the mechanical properties of thin surface films and how they are effected by reagents and heat treatment. Results are given of studies of oxide films on high purity aluminum. IF a wire is subjected to plastic deformation by torsion and then released, it untwists in the normal after-effect, but under certain circumstances the untwisting is abruptly lessened or reversed by the application of an etchant to the wire.1,2 This abnormal after-effect may occur, for example, if there is a coherent oxide film on the surface of the wire which is removed by the etchant. Following a suggestion of A. H. Cottrell that predicted this effect, it is attributed to dislocations that had piled up beneath the oxide layer and represents the rapid release of residual stresses caused by these dislocations. When the layer is removed, the stress relief may be by escape of piled-up dislocations from the metal, or by an activation of latent sources of dislocations located at the surface, together with rebalancing of elastic stresses to compensate for the loss of stressed material, as in a residual stress analysis determination, these mechanisms acting singly or in combination.' The slower the attack of the reagent, the more gradual is the stress relief and the smaller the change in strain rate when the reagent is applied. A study has been made of the factors that influence the magnitude of the normal and abnormal after-effects with the object of developing techniques suitable for a quantitative investigation of the influence of various surface films on dislocations in wires, and of the rate and extent of the attack on the films by different reagents. It was found that reasonable sensitivity and reproducibility could be achieved if a suitable choice of variables was made and if these variables were held constant through a series of experiments. The method was then applied to a study of oxide films produced and treated in different ways on the surface of high purity aluminum wires, and to a study of the damage to these films caused by various reagents. Experimental Procedure The material used throughout this work was prepared from 99.9968 pct Al. This high purity aluminum was melted, cast into 1/2 in. diameter ingots, and then swaged and drawn without intermediate annealing to 0.040 in. diameter wire. A sketch of the apparatus employed for twisting is shown in Fig. 1. The test wires were mounted into the apparatus by cementing one end of the wire to the beaker and the other to the tube with laboratory wax of high melting point. The length of the wire between the waxed joints was 4.2 & 0.2 cm. Extreme care was taken during mounting to avoid cold-working the wire. The wire was twisted through 335" in 2 to 4 sec by rotating the pinion on the gear box until the vertical post on the rotating table, which was initially touching the horizontal stop, was arrested by the stop. All the tests were conducted with apparatus and reagents at the same temperature (about 25°C). In all tests, except those where the duration of the initial torque was investigated, the torque was applied for a period of 2 min. At the end of this time the table was rotated back a few degrees away from contact with the stop and the wire allowed to untwist. The after-effects were measured by reflecting a beam of light from the mirror shown on the apparatus. After the wire had untwisted for 6 min, a reagent was carefully poured into the beaker and thereby applied to the surface of the wire.. In some tests the liquid in the beaker was removed after a few minutes and replaced by an-

Jan 1, 1954