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By John S. Alexander

DURING the past few years the block coal of Indiana has been talked about and written upon to such an extent, that almost every one at all interested in such subjects, has been made acquainted with the area and geographical position of the field, the quality and peculiar properties of the coal, the thickness of the veins, the manner of mining, etc. The writer, therefore, taking for granted that to those present all this is familiar ground, desires more especially to call attention to the position this coal takes in the market, and at those points of consumption where it is brought in direct competition with rival fuels. Chicago, thus far, has been the chief consumer of Indiana block coal, the distance from the mines at Brazil, via Terre Haute and the 25

Jan 1, 1873

By W. W. Stephens, W. J. Kroll, H. P. Holmes

THE only two methods for producing commercial quantities of malleable zirconium, up to now, have been using magnesium reduction of the anhydrous chloride under a neutral gas, and using purification of raw zirconium by the iodide dissociation method on a hot filament. The purity of the metal obtained by the latter process is about the same as that resulting from the chloride reduction, with the exception of the oxygen content, which may be about 0.05 pct lower in the iodide metal. Even traces of oxygen have a strong hardening effect on zirconium. Since, in the iodide process, the impurities, Si, Al, Fe, Ni, and Mg in the raw zirconium used, are carried over, it would appear uneconomical to use this method of refining solely to eliminate the traces of oxygen, unless very soft metal is desired. One important step to improve the iodide method, namely, dissociating pure iodide made from carbide and recycling the iodine, which would change this refining process into a method for extracting zirconium from the ore, has not yet been made. The Bureau of Mines, by using the chloride reduction, wanted to produce quantities of a reasonably pure and malleable metal at low cost for large-scale industrial use. This aim has been achieved, and a pilot plant permitting production of 600 lb of malleable zirconium per week will be described (fig. 1). Briefly, the Bureau of Mines process consists of reducing purified gaseous anhydrous zirconium chloride with fused magnesium under a noble-gas atmosphere. The reaction product, magnesium chloride, and any excess magnesium metal present are removed from the sponge zirconium in the next step by fusion and evaporation in a good vacuum at about 925°C. In this process, care is taken to keep air out of contact with the hot metal, which otherwise would contaminate the product with oxygen and nitrogen. Both these impurities embrittle zirconium even when present in an amount as low as 0.1 pct. A number of previous reports1-3 describe the method and the various improvements that finally led to a workable process. The major steps made were the production of large quantities of carbide, which is the raw material for producing the chloride, its chlorination with reasonable efficiencies, and the elimination of iron trichloride contained in the raw chloride, as well as that of the zirconium oxide which is always present in this product. The physical nature of the anhydrous chloride, which sublimes at 331°C at atmospheric pressure and melts at 420°C under a pressure of 25 atm, made it necessary to provide a special safety device on the purification and reduction vessels in the form of a lead-alloy seal, permitting escape of excess gases if pressure tended to build up. The main difficulties encountered in the reduction and in the following step, salt separation in a vacuum at elevated temperature, were caused by the material from which the reaction pot was constructed—iron. This metal reacts with zirconium at about 940°C with formation of a eutectic. The last step, salt separation by evaporation of the magnesium and magnesium chloride in a vacuum, is quite unconventional and has not been used before on such a scale. It is only due to the improved construction of high-vacuum pumps, especially oil-diffusion pumps, that such a method could be used. The various steps of the Bureau of Mines process, as described in the general outline above, may be summarized as follows: (1) production of the carbide, (2) chlorination of the carbide, (3) purification of the raw chloride, (4) reduction of the pure chloride with fused magnesium, (5) separation of excess magnesium and magnesium chloride in vacuum at elevated temperature, and (6) melting of the sponge obtained. Production of Carbide The arc furnace, described in a previous report,' was improved both to reduce the graphite consumption caused by the burning of the bottom plates and to concentrate the heat in order to obtain better power efficiency. This was achieved by providing the bottom with graphite plates entirely embedded in refractory bricks, the contact with the current being made with three water-cooled copper plugs. Figs. 2 and 3 show the arrangement. The crucible, made

Jan 1, 1951

By T. Egleston

ALTHOUGH the success of metallurgical operations depends so largely on the possibility of finding proper refractory materials, which enter so prominently into the cost of their operations, it can hardly be said that our knowledge of them is in a very satisfactory condition, or even that we know very much about them, beyond a few facts which have been gathered through their use. Experience, as a general thing, is an excellent master, but the requirements of * This article was written at the suggestion of the Committee of the Institute on Refractory Materials, with a view of calling attention to the anomalies and difficulties of the subject. It was hoped that its discussion would eventually lead to the appointment of a Commission, by the great metallurgical interests of the United States, to investigate the whole subject, since it is believed that a better and cheaper artificial product can be made than any now in use, and that many other important incidental results would be accomplished by such an investigation.

Jan 1, 1876

By David E. Jones, Dean K. Hunt, C. Y. Chen

INTRODUCTION Of all the numerous geological hazards that threaten the well-being of urban areas in the United States, probably none is so widespread, persistent, and diversified as surface subsidence (HRB-Singer, Inc., 1977). Simply defined, subsidence is the vertical displacement or sinking of the ground surface caused by either natural phenomena or man's activities. The downward movement, however, can be accompanied by horizontal movement, strain, tilt and even by a locally upward movement. Damage to structures and the environment can result from any of these movements. Extracting subsurface materials, fluids and solids, accounts for most man-induced subsidence in the United States. Among all the mining-related subsidences, the collapse of voids created by underground coal mining has been the major cause in inflicting surface damage (Comptroller General of the United States, 1979). Subsidence from coal mining may occur within a few weeks or be delayed for years, depending upon the mineral layer's depth below the surface, the overlying rock strata's characteristics, the extent and methods of mining that were employed, and the time deterioration of pillar and mine structure. Unless underground resources are not mined or control measures are implemented to prevent or minimize damage, some degree of surface subsidence and its accompanied deleterious effects are often inevitable. The ways to control the subsidence and minimize surface damage may include: 1. Precautionary measures built into new structures or surface features. 2. Preventive works applied to existing structures or surface features. 3. Mine design incorporating special underground layouts. 4. Any combination of the above measures. Upon the enactment of Public Law 95-87, the Secretary of the Interior, through the recently created Office of Surface Mining (OSM), was authorized to promulgate rules to regulate mining reclamation including subsidence control. Proposed on September 18, 1978, these rules were finalized, following public comment and hearings, on March 13, 1979, as part of the permanent regulatory program for the regulation of surface mining and reclamation operations which include the surface effects of underground mining. On January 28, 1981, Secretary Watt of the Department of the Interior issued an order to re- quire all agencies to identify with recommendations all regulations which are believed to be excessive, burdensome or counterproductive. Also on February 17, 1981. President Reagan issued Executive Order No. 12291 requiring all Federal agencies to conduct a regulatory review to make a determination that each promulgation of a regulation is clearly within the authority delegated by law and consistent with Congressional intent (Federal Register, 1981). As a result, OSM initiated the regulatory reform to revise the permanent regulatory program. Following a brief discussion of the technical aspects and the effects of subsidence on man and his environment, this paper presents a historical overview of how rules and regulations are used to govern the subsidence related problems. The development of the regulation of subsidence under Public Law 95-87, the Surface Mining Control and Reclamation Act of 1977 (SMCRA or the Act) are also discussed, including the new regulations being developed under the regulatory reform program. SOME TECHNICAL ASPECTS Am EFFECTS OF FINE SUBSIDENCE An extensive historical review of mining subsidence is given by Zwartendyk (1971) and Shadbolt (1978). Comprehensive technical presentations have been given by Henry (1956), King and Whetton (1957), Hall and Orchard (1963). Muller, et al. (1968). Grard (1969), Voight and Pariseau (1970). Kapp and Williams (1972), Cummins and Given (1973), Brauner (1973) , and NCB (1975). A theory of surface subsidence due to underground mining was perhaps first fundamentally stated by a French engineer, Toillez, in 1838, and formulated by a Belgian engineer, Gonot, in 1839 (Goldreich, 1913, cited by Zwartendyk, 1971). Since that time,

Jan 1, 1982

By E. R. Johnson

The copper concentrator of the Braden Copper Co. is at Sewell, Chile, on the westem flank of the main Cordillera of the Andes, at an air distance of approximately 50 miles southeast of Santiago, the capital of Chile. The region is mountainous and space is at a premium because of the rough terrain and the danger of snowslides. The ore, a porphyry copper, is mined by a block-caving method in the El Teniente mine. It is hauled to the crushing plant, a distance of 2.6 miles, through a tunnel because of the severe climatic conditions. The usual large, coarsely set, primary reduction machines found in many ore-treating plants are not required because of the mining method employed and the limiting 12-in. spacing of the grizzlies at the head of each ore pass in the mine. It is the purpose of this paper to describe the numerous improvements made in the crushing section of this large flotation concentrator during the past I5 years to increase the efficiency of the plant and to raise the daily output from around 20,000 to 30,000 tons. The reader should keep in mind that all changes were made within the existing building because of the limited space and the high cost of the heavy mill construction required to withstand the snow loads. The present plant, as well as the former, operates on a 24-hr, 7 days a week basis. The crushing plant commenced operations at its present site in 1921, the main equipment being No. 7½ gyratories, followed by 48-in. horizontal Symons disk crushers. Fines were removed by I-in. stationary grizzlies ahead of each unit. In 1924 a third stage of crushing was provided by the addition of 55½-in. rolls in open circuit. During 1925, the Symons disks were replaced by 73½-in. rolls. All the rolls were changed to closed circuit, with elevators and screens to give a final product of 9 pct plus 3-mesh. The flowsheet of a typical crushing section of this period is shown in Fig I. The ore was withdrawn from a common bill serving the five crushing sections in the plant by means of any number up to six 36-in. wide-apron feeders, which discharged onto a common conveyor belt. This conveyor was equipped with a magnetic head pulley and the crusher attendant was stationed near the discharge end to pick out pieces of mine timber that might be in the ore. The ore was discharged over a 13/4-in. spaced bar grizzly and the oversize of this grizzly was crushed by a No. 7½ McCully gyratory crusher set at 13/4-in. opening on the closed side. The grizzly undersize joined the gyratory discharge and was conveyed to a set of 73½ by 20-in. Garfield rolls set at I in. These rolls operated in closed circuit with a bucket elevator and two vibrating screens placed in parallel.

Jan 1, 1949

By B. H. Caudle, W. J. Bernard

Factors which influence the success or failure of a waterflood can seldom be determined in the laboratory. For this reason pilot waterfloods are initiated in a repreventative portion of the oil reservoir in question. For a pilot flood to predict quantitatively the recovery to be expected in a field-wide waterflood operation, the pilot area must behave as though it were confined (surrounded by similar areas). In this study, laboratory fluid-flow models were used to determine the simplest pilot pattern, for particular conditions of mobility ratio and initial gas saturation, that would behave as though it were confined. Pilot patterns studied ranged in complexity from a single inverted five-spot to a grouping of nine regular five-spots. Only the innermost producing well in each pattern was studied. Model results showed that the optimum number of wells in the pattern depends upon the oil-water mobility ratio and the expected oil-bank size. Unfavorable mobility ratios will, in general, require more wells in the pilot pattern than will favorable mobility ratios. Pilot patterns in reservoirs which contain a dispersed, flowable, free gas saturation will require fewer wells than for the under-saturated case. The single inverted five-spot pattern was found to be unsatisfactory for predicting behavior of fully developed waterfloods. In particular, it is possible that, in reservoirs which contain a flowable, dispersed gas phase, the oil bank will never be observed at the producers due to the large amounts of free gas which continue to be produced with the oil. INTRODUCTION One method which has been used to predict the performance of a waterflood is the pilot flood. The pilot waterflood is a flood which involves only a small cluster of the reservoir wells and is located in a small, representative portion of the reservoir. The object is that oil produced from the pilot can, in some way, be related to the oil recovery to be expected from a field-wide expansion of the waterflood. However, these field pilot waterfloods have often been unreliable in the prediction of oil recovery in a fully developed waterflood. This unreliability has also been demonstrated in several laboratory studies of pilot floods. Some of the investigators have shown that there are situations in which the pilot flood oil production is far too optimistic with respect to the oil recovery in the fully de- veloped flood. Others4-G have shown that the pilot results can also be pessimistic, especially if the pilot waterflood is initiated in an oil reservoir which has been depleted by primary recovery and is at very low pressure. The major reason for this unreliability of pilot water-floods is the migration of fluids into or out of the pilot area. By the well-known method of images, if straight lines can be drawn to represent vertical planes of symmetry in a porous medium which contains pressure sources and sinks (injectors and producers), then these lines are invariant streamlines, or lines across which there is no potential gradient, and therefore no flow. In an actual reservoir, these lines of symmetry can never be established exactly because of reservoir inhomogeneities and irregular reservoir boundaries. However, if the reservoir is relatively large and contains wells in repetitive patterns, these lines of symmetry are commonly assumed to exist for the pattern units sufficiently far removed from the reservoir boundary. Lines of symmetry for the five-spot injection pattern are shown in Fig. 1. Each five-spot unit in this figure can be considered confined with respect to flow across its boundary. In pilot floods this is not the case. The lines of symmetry for the pilot patterns investigated in this study are shown in Fig. 2. It is obvious that the fluid within these pilots is not confined and is therefore able to migrate into or out of the pilot area. Intuitively, one can see that, if more wells are added to the pilot, the innermost unit tends to behave more and more like the confined pattern. However, there is a practical limit to the number of wells which should be placed in the pilot. This limit is usually determined by economic factors. It was the purpose of this study to use laboratory fluid-flow models to determine which of the previously mentioned pilot patterns will force the innermost producing well to behave as it would in a fully developed waterflood. Since fluid migration is influenced by initial saturation conditions and the mobility ratio, these factors were included in the study. The ultimate objective of this study was to develop data which would allow the operator to choose a pilot pattern and operating conditions that will yield a production history which can be applied directly as an estimate of the performance of each production well of the fully developed waterflood. BASIS FOR THE STUDY The basic problem of field pilot floods is the migration of the reservoir fluids into or out of the pilot area. This problem has been the subject of previously reported model studies on pilot floods. These studies have been concerned mainly with the development of arbitrary "correction factors" to be applied to the simple, unconfined pilot systems such as the single five-spot. The correction factors were intended to adjust the production history of the un-

By R. V. Smith

The theoretical background for calculating friction factors for flow in gas wells by two methods is presented. The first method, requiring pressures, temperatures and specific volumes of the flowing fluids at various depths in the well bore, shows how the mechanical-energy-balance equation for vertical flow may be graphically integrated over the actual path of the expansion of the fluid in the well. Thus, assumptions regarding the effective temperature and effective compressibility of the fluid in the well are avoided. The second method presents an equation derived on a basis of the assumptions that both the temperature and the compressibility are fixed at constant effective values throughout the flowing column of gas. The second method provides a convenient and practical means of calculating friction factors for gas wells and lends itself readily to the problem of calculating subsurface pressures in a flowing gas well. The application of both methods to actual test data taken on a flowing gas well is illustrated in the paper. INTRODUCTION As friction factors for the producing strings of flowing gas wells cannot be measured directly and must be calculated from flow-test data, study of the methods of arriving at friction factors is a necessary adjunct to understanding the characteristics of flow in gas wells. There are two methods of calculating friction factors for gas wells; they differ from one another mainly in the treatment of the path of expansion of the fluid in the well. In the flowing well, the energy consumed in lifting the fluid from the bottom to the top of the well, overcoming the friction between the moving fluid and the pipe walls, and increasing the velocity of the fluid as it flows up the producing string is supplied by expansion of the flowing fluid. The available energy is determined by the expansion of the fluid that follows a path determined by conditions of temperature, compressibility and phase changes of the fluid during the expansion. A means of evaluating the available energy in a flowing gas well and determining the proportion of the available energy used in lifting the gas, overcoming friction, and increasing the velocity of flow is developed in this report. Knowing how much energy is consumed in overcoming friction makes it possible to calculate friction factors for given flow rates in given sizes of pipes in wells. Friction coefficients, as used in this report, are dimension- less proportionality multipliers used in the flow equations to satisfy the equality between the terms of the equation. The square root of the reciprocal of the friction coefficient is termed the friction factor. It has been known for many years that friction factors may be computed directly from mathematical formulas based on certain assumptions regarding the temperature and compressibility of the moving fluid in a well. A general equation is presented in this report without assumptions for vertical flow of fluids and a conventional-type equation is derived on the basis of assumptions that fix the temperature and compressibility at constant values. Accurate pressures at the sand faces in wells are required in the method of determining the productivity of gas wells, as outlined by Rawlins and Schellhardt1 in Bureau of Mines Monograph 7. Where measurements are not made with subsurface-pressure gauge; or static gas columns are unavailable, flowing pressures customarily are calculated at the sand face in the well by the use of the well-known Weymouth formula1. Natural gas engineers have realized that errors introduced by the use of friction factors as given by the Weymouth formula are relatively unimportant in testing low-capacity gas wells; they also know that such factors are important considerations in testing large-capacity gas wells. Accordingly. present research on the productivity of gas wells at the Petroleum Experiment Station of the Bureau of Mines, Bartlesville, Okla., is being directed toward measurement of the pressure loss due to friction in flowing gas wells. It is beyond the scope of this report to show how friction factors vary with rate of flow and in pipes of different diameters, as it is intended only to develop and illustrate the use of mathematical expressions for calculating friction factors from flow-test data. The equations presented apply only to turbulent flow in circular pipes. ENERGY RELATIONS FOR FLOW OF FLUIDS2 The concept of conservation of energy is usually the basis of any study of fluid flow through vertical pipes as in gas wells, horizontal pipe lines, or orifices. In deriving equations, the following symbols are used:

Jan 1, 1950

By John S. Alexander

DURING the past few years the block coal of Indiana has been talked about and written upon to such an extent, that almost every one at all interested in such subjects, has been made acquainted with the area and geographical position of the field, the quality and peculiar properties of the coal, the thickness of the veins, the manner of mining, etc. The writer, therefore, taking for granted that, to those present all this is familiar ground, desires more especially to call attention to the position this coal takes in the market, and at those points of consumption where it is brought in direct competition with rival fuels. Chicago, thus far, has been the chief consumer of Indiana block coal, the distance from the mines at Brazil, via Terre Haute and the

New York Meets first Wednesday after first Tuesday of each month. J. E. JOHNSON, JR., Chairman. EDGAR RICHARD, Vice-Chairman. D. M. LIDDELL, Secretary, 7 Wall St., New York, N. Y. C. A. BOHN, Treasurer. JOHN V. N. DORR, LEWIS W. FRANCIS. Boston Meets first Monday of each winter month. R. L. AGASSIZ, Chairman. JAMES G. CARLETON, Vice-Chairman. E. E. BUGBEE, Secretary-Treasurer, Mass. Inst. of Technology, Cambridge, Mass., W. E. C. EUSTIS. G. A. PACKARD. Columbia Holds four sessions during year. Annual meeting n September or October. W. H. LINNEY, Chairman. OSCAR LACHMUND, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. STANLY A. EASTON, S. SHEDD. Puget Sound Meets second Saturday of each month SIMON H. ASH, Chairman. I. F. LAUCKS, Vice-Chairman. CHARLES SIMENSTAD, Secretary-Treasurer, 425 Lyon Bldg., Seattle, Wash. GLENVILLE A. COLLINS, JOHN N. POTT

Jan 7, 1917

Mining as an industry of Utah had its inception in the activities of United States soldiers who came to the Salt Lake valley under the command of Gen. P. E. Connor, founder of Fort Douglas, in October, 1862. Many of these soldiers were from California and naturally employed their spare time in the search for minerals. Although their military status did not permit them to make locations in their own names, they assiduously prospected the region in accordance with their own knowledge and with in- formation conveyed to them by Indians and others. Their efforts were encouraged by their commander, who thereby fairly earned the title of father of the industry here, and by their other officers, and many discoveries that subsequently proved of great value were made by the soldiers. No systematic prospecting or mining had been done in the Territory previously although early Mormon settlers in the southern portion had mined a little ore from time to time in order to provide supplies of lead for bullets. The Mormon leaders at that time did not encourage mining. They held that agriculture was more important and profitable for their followers.

Jan 1, 1925

NEW, MEMBERS The following list comprises the names of those persons who became members during the period July 10, 1916; to July 31, 1916: BOYD, ROBERT RUSSELL Supt:,-Arizona -Commercial Min Co., Globe, .Ariz. BRADLEY, HENRY FRANKLIN, Chem, American Smelt & Ref. Co. Murray,:Utah: BROWN, THOMAS ELLIS, JR..:'. L .:.::..55 Hill, St;; Morristown, N. J. CARY, WEBSTER P., Expert Operator,-General Engineering. Co:, Salt Lake City, Utah. CLARK, ALONZO WEBSTER 3223_ Scottwood Ave., Toledo, Ohio. CORP, CLIFFORD Old Dominion Copper Min. & Smelt. 60., Globe, Ariz. CROMBIE, W. RANSOM, Min. Engr Detroit Copper Min. Co., Morenci, Ariz. DELANEY, EUGENE A., Chief Engr., Berwind-White. Coal Mining -Co., Windber, Pa ELBELT, WILLIAM HENRY, Dept. Foreman., Chino Copper Co., Hurley, N. Mex. FOSTER, L. JULIO, Mgr., Minas i Fundicion ; ?La Junta," San Bernardo, Chile, South America. GASKILL, JAMES PHILLIPS, Genl. Mgr.,.Ajo Cons. Copper Co., Ajo, Ariz., via Gila, Ariz. .

Jan 9, 1916

By H. W. Hitzrot, R. A. Limons, L. V. Fegan

The authors have developed and tested a new method for measuring pellet-bed temperatures in the traveling-grate or the shaft furnace. This method-using silver-palladium alloy wires as indicators-is less costly and less time-consuming than existing methods. Silver palladium wires, having specific melting points in the 2000° to 2500°F range, are enclosed in ceramic capsules. Each capsule is placed in a nichrome wire basket filled with a sample of green pellets, the baskets being the means for recovering the capsule after firing. After the encapsulated wires have been exposed to the firing cycle, the alloy wires are examined to determine the maximum temperatures attained by the pellet sample. This gives accurate, rapid determinations of maximum temperatures attained during pellet induration in either the traveling-grate or shaft furnace.

Jan 6, 1965

By R. Wiesenthal

A method is developed for improving the low recovery efficiency which results when viscous oils are flooded by water. Viscous oil has been diluted with a lighter liquid miscible in it in any ratio which produces a mixture possessing a reduced viscosity and which is then displaced by water. Light gasoline was used in these tests to reduce the viscosity of the oil in place. Oils possessing viscosities in the range of 1.28 to 324 cp at the test temperature of 30C were displaced from a cylindrical unconsolidated sand core, with a length of 2 m (6.6 ft) and a diameter of 10 cm (3.9 in.) at a flood of 6.27 cc/sq cm/hr. In two test series up to I PV of light gasoline was injected into the core before water flooding. In the first series the recovery of a low-viscosity oil (1.28 cp) increased as the volume of light gasoline was increased. However, only the oil which could not be recovered by water flooding alone could be replaced by the light gasoline. In the other series, the recovery of a more viscous oil (13.5 cp) was not increased even if large quantities of light gasoline were injected. An oil bank built up ahead of the water front so that the flood water met with equivalent saturation conditions, as would be the case in flooding solely with water. However, the recovery of more viscous oils could be increased substantially when the core was first flooded with water, followed by a slug of light gasoline, and then flooded with water again. Furthermore, an oil bank ,built up ahead of the second water front. The formation of this oil bank is particularly favorable for the displacement process; the greater part of the light gasoline injected was pushed out of the core ahead of the oil and recovered. Using a light oil of low viscosity, it was possible to replace only the residual oil that could not be recovered by water flooding by the light gasoline. As the basic study had shown that highly viscous oils could be recovered by flooding first with water, then with light gasoline, followed by a second injection of water, the study was extended by tests made with reservoir fluids and cores taken from the low-gravity oil reservoir of the Wietze field, Germany. A great increase in recovery over flooding with water alone was obtained in these tests. The results may show a way to recover high-viscosity oils by a comparatively simple flooding procedure. INTRODUCTION In fields where oil recovery has not benefited from natural water drive, increased recovery may be obtained by the injection of water into the reservoir, especially in the case of fields which produce high-gravity, low-viscosity oil. There is a rather close relation between the viscosity of the reservoir fluid and the recovery that can be obtained by water flooding. As the viscosity increases the oil recovery decreases proportionately, so that an oil viscosity about 30 times that of water is generally considered to be the upper limit for an economically successful water flood.' This limitation has been recognized theoretically by Buckley and Leverett,' and has been verified by numerous laboratory flooding tests, such as by Croes and Schwarz,V n the viscosity ratio range of oil to water from 1 to 500. The reason for the inferior recovery of viscous oils by water flooding can best be understood by considering the mechanism of flood tests. In such tests water is introduced into one end of a sand-packed tube which is saturated with oil of the viscosity to be tested, and oil is produced from, the other end. Oil, with a viscosity lower than that of water, is pushed ahead of the advancing water with considerable uniformity, and irregularities in the displacement process tend to be eliminated as the oil saturation decreases and the water saturation increases. However, oil recovery is not complete, for the water forms interfaces with the oil and traps residual oil droplets in certain of the pore spaces. These residual oil droplets are distributed rather uniformly through the sand, and they are not susceptible to recovery regardless of the amount of water passed through the test cylinder. In the case of an oil possessing a viscosity greater than that of water, the injected water tends to move irregularly through the sand in the test cylinder. At the place in the sand where initial water movement takes place, resistance to the movement of water is lowered and the water finger so formed will grow perceptibly; it will extend to the outlet end of the test cylinder so that a breakthrough of water takes place long before much of the oil-saturated volume of the sand has come in contact with water. Once the breakthrough of water takes place, the water-oil ratio is gradually approaching the economic limit, even though much of the oil in the test cylinder remains unaffected by water. Disconnected drops of oil are trapped in the portion of the sand that has been invaded by water, just as when an oil of low viscosity is flooded. The poor recovery of the more viscous oils, therefore, is due to the irregularity of water movement through the test cylinder, and the rate of water movement through restricted sections of the oil-saturated sand increases with the more viscous oils. There are three ways whereby the recovery of viscous oils by water flooding can be improved:' (1) adding materials which will increase the vis-

Jan 1, 1965

By H. I. Smith

WHEN Spain established colonies on the North American continent, some of her land grants, in what is now the United States, reserved to the Crown deposits of gold, silver, and mercury. Later mineral rights were reserved under some of the English Crown charters involving land in the eastern part of North America, with provisions for the payment of royalties thereon to the Crown. Reservation of mineral deposits to the United States Government was instituted by an ordinance of Congress on May 20, 1785, which applied to such deposits in the Northwest Territory, then north of the Ohio River and east of the Mississippi River, and provided that there should be reserved "one third of all gold, silver, lead, and copper mines, to be sold or otherwise disposed of as Congress shall hereafter direct." Little was known then of the mineral resources of the country; the Great Lakes copper region had just come into the possession of the United States by treaty and much of the western mineral land still belonged to France and Spain. The policy of leasing mineral deposits was enacted by Congress under the act of March 3, 1807, which provided that "the President of the United States shall be, and is hereby, authorized to lease any lead mine which has been or may hereafter be discovered in the Indiana Territory, for a term not exceeding five years," and in the same year the Government reserved 345,600 acres of land in northern Illinois, valuable for lead. In 1816 Congress provided that in all cases where a tract of public land containing a lead mine or salt spring was applied for by settlers on the public domain, no permission to work the mine or spring would be granted without the approbation of the President of the United States. By the act of March 1, 1847 (9 Stat. 146), the control of mineral lands was transferred, with all records, from the War Department to the Treasury Department, and by the act of March 3, 1849 (9 Stat. 395), supervisory powers over lead and other mines of the United States were transferred to the Secretary of the Interior. Following the discovery of gold in California in 1848, President Polk advocated the leasing of mineral lands acquired from Mexico under the treaty of 1848. However, owing to the lack of communication and transportation facilities and the consequent difficulty of checking on production and operations, leasing was found impracticable. Mining was permitted to be carried on in each district under rules made by the miners themselves and patterned after the Mexican mining system. To meet the situation, Congress enacted mining laws in 1866, 1870, and 1872, which provided for possession by location and for private ownership, after discovery, by patent of essentially all mineral deposits belonging to the United States, except coal. Many other acts were passed by Congress applying to specific regions and states, reserving salt, lead, or other minerals, some of which provided for the leasing of such deposits. However, very few if any leases were issued thereunder. Not until 1901 (31 Stat. 745) were the mining laws extended to include salt, and in 1910 they were revised to specify salines and associated products. At the turn of the century, it became more and more evident that the mining laws developed for metallic minerals were not practical for the development and conservation of oil and gas, coal, potash, phosphate, or oil shale. Following withdrawals by the Secretary of the Interior as authorized by the act of June 25, 1910, the Department of the Interior recommended leasing legislation; however, it was not until February 25, 1920, that the Mineral Leasing Act was passed by Congress. This act authorized leasing all public lands potentially valuable for oil, gas, coal, phosphate, sodium, or oil shale. The Organic Act, creating the Geological Survey in 1879, imposed upon its director the duty of classifying the public lands.' The early years of the Survey were devoted largely to the accumulation of fundamental data and, with only minor exceptions, land classification was not seriously undertaken until 1906. Since that year, it has been actively pursued with respect particularly to leasable minerals and water power values. On March 3, 1873 (17 Stat. 607) Congress authorized the sale of coal lands of limited acreage to individuals at $10 to $20 an acre, depending on the distance from a railroad, and in 1907 a new scale of prices was adopted by the Secretary of the Interior, based, more logically, on the quality and thickness of the coal deposits, their depth below the earth's surface, and their accessibility. At that time it was much cheaper and easier to obtain incidental title to coal rights under the homestead laws at $1.25 an acre. On March 3, 1909, the first separation act (35 Stat. 844) became a law. It authorized patents, with a reservation of the coal and mining rights involved to the United States, to persons who in good faith had entered public lands under the non-mineral land laws prior to withdrawal, classification, claim, or report that such lands were valuable for coal. It solved the problem only partially, and the practice thereupon adopted by the department of making coal withdrawals "from all forms of entry" instead of "from coal entry" expedited the more complete solution effected by later acts. By the act of June 22, 1910 (36.Stat. 583) withdrawn and classified coal lands were declared subject to entry under the homestead, desert land, and Carey acts, provided a waiver of the coal rights accompanied the application, and by the act of April 30, 1912 (37 Stat. 105) the same privilege was extended to State selections and isolated tracts. The act of August 24, 1912 (37 Stat. 496) extended the separation policy to lands withdrawn for oil and gas in Utah, and finally the act of July 17, 1914 (38 Stat. 509) extended it to all nonmineral filings on public lands theretofore or thereafter

Jan 1, 1955

THE Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties situated at 29 West 39th Street in New York City.

Jan 1, 1946

By H. W. Young

Development of high-tension outdoor substations during the past few years has been due primarily to economic reasons. The demand for power in small communities could not be met with the conventional and Fig. 1.—33,000-VOLT step-up outdoor air-break switch and substation installation outside of a powerhouse generating at 2300 volts stepping up to 33,000. Twenty-one coal mines are supplied from lines leading from this installation. comparatively expensive indoor types unless the rate for service was materially increased. To prove that the problems lncident to development have been solved successfully, it is only necessary to point to the wide adoption of outdoor substations by utility companies. Passing at once to the question as to whether outdoor substations are applicable to

Jan 1, 1920

By Lewis V. Wade

U.S. Bureau of Mines efforts under longwall research programs to develop the capability to predict support requirements for longwall/ shortwall support systems are discussed. Ground control studies are being conducted in conjunction with several longwall/shortwall demonstration projects. Geologic, support performance, and strata behavior are being documented on these projects. A hypothesis is presented for the prediction of support requirements.

Jan 1, 1978

The Pueblo Viejo Mine, a 7, 250 mtpd (8,000 stpd) gold-silver cyanidation plant built by Rosario Dominicana S. A., was described in Volume I of this monograph. At the time of writing that volume, Pueblo Viejo had not yet gone on-stream and operating data or costs could not be presented. Since that time this information has been obtained and several interesting modifications and an expansion have been made to the plant. Because Pueblo Viejo is the largest open-pit gold mine in the world and one of the world's leading gold-silver operations with production of approximately 31 kg (1,000 oz) gold and 125 to 155 kg (4,000 to 5, 000 oz) silver per day, the authors have updated the previous data and flow sheet. The Dominican Government, which held a 4670 interest in Rosario Dominicana S. A., completed purchase of the mine to gain full control in 1979. Rosario Resources will continue to manage the mine, at least until the end of 1980. Gold was produced at Pueblo Viejo almost 500 years ago with initial production in the year 1505. Rosario Resources became interested in the property in 1969 and found surface oxidation had rendered the upper portion of the ore body amenable to direct cyanide treatment. The treatment of the underlying gold-bearing sulfide zone is still undergoing metallurgical studies. The ore is considered to be a laterite; and because there appeared to be few boulders in the ore zone, only a 400 m (16 in. ) square grizzly was initially installed ahead of the mills when the plant went on-stream in late 1974 at a design capacity of 7,250 mtpd (8,000 stpd). Operation also proved the ore to be harder than was originally anticipated. During 1967 a 1. 25 m by 1. 5 m (48 in. by 60 in. ) jaw crusher was installed to -feed the 1, 000 mt (1, 100 st) mill bin. Minus 200 mm (8 in.) crushed ore is fed directly to two 5.5 m by 1. 8 m (18 ft by 6 ft) semi-autogenous mills re-powered with 750 km (1,000 hp) motors and 50 mm (2 in.) grates. Each mill product is screened at 13 mm (1 /2 in.) by a vibrating screen. Screen oversize from each mill is combined on a single return belt equipped with a magnetic head pulley for grinding ball removal. The non-magnetic oversize is then split into two fractions for return to the primary mills. Originally, a minus 6 mm (1/4 in ) product was made on each screen and fed to a 300 kw (400 hp) 2.6 m by 3. 7 m (8-1/2 ft by 12 ft) regrind mill. During a plant expansion in 1978, an intermediate mill of 746 kw (1,000 hp) was installed to operate in open circuit on the combined primary mill

Jan 1, 1981

By W. J. Carlson, S. M. Parmerter, I. Iwasaki

This article discusses the effect of physical and chemical modifications of starches on the anionic and cationic flotation of silica from oxidized iron ores and magnetite-taconite concentrates. It also deals with the results of the interaction of starch, pH, and calcium ions on the flocculation, clarification, and filtration of iron ore slimes and magnetite-taconite tailings. Starches, particularly when an-ionically modified, were found to be effective depressants in anionic silica flotation. British gums and dextrins were beneficial for oxidized iron ores, but none of the starches or starch derivatives appeared to have any effect on magnetite-taconite concentrates. The flocculation and filtration of iron ore slimes were affected most strongly by the level of starch, to a lesser degree by the pH, and virtually not at all by the level of calcium chloride. The clarification of iron ore slimes was complexly dependent on these three factors. The flocculation of magnetite-taconite tailings depended mainly on the level of starch, whereas their clarification depended on the level of lime. As previously reported in the literature, selective flocculation and partial upgrading of a semitaconite could be readily attained with starch and calcium chloride. A previous article discussed some of the parameters that are important when various corn starches are applied to the soap flotation of activated silica from iron ores and to the flocculation of iron ore slimes.' Methods of solubilizing the starches and the molecular size after mechanical and thermal treatments, as inferred from the viscosity measurements, were shown to influence the adsorption characteristics on iron ores, and the residual concentrations of both calcium ion and starch in the pulp liquor were in direct correlation with the flotation and flocculation behavior.2-4 The present article summarizes the results of more recent tests conducted to ascertain the role of starches and starch derivatives in various phases of iron ore beneficiation. The scope of this investigation has been extended to include not only anionic and cationic flotation, but also the flocculation and filtration of iron oxide slimes, the selective flocculation and partial upgrading of semitaconites, and the flocculation and clarification of magnetite-taconite tailings —all problems that are of vital importance to the iron ore industry of Minnesota. By combining a practical approach with adsorption studies and by using single-mineral systems5 in these research efforts, it is believed that the ultimate goal of developing a suitable modification of starch structure may be realized. The topics covered in this article are limited to the empirical aspects of the research program on the depressant activity of starches and products in the cationic and anionic flotation of silica and of their role in flocculation, water clarification and filtration. ANIONIC SILICA FLOTATION In the soap flotation of activated silica from iron

Jan 1, 1970

By K. C. Strebig, C. W. Schultz, A. A. Selim

For some time researchers have attempted to in- crease drilling efficiency (and therefore reduce costs) by adding certain chemical agents to the circulating medium. The effect of some organic additives on the diamond drilling of quartzite was recently investigated in the laboratory by personnel of the U. S. Bureau of Mines. In these tests, the penetration rate and bit life were found to increase with the use of additives. In addition, an economic analysis of a hypothetical 1000-ft hole showed that additives can reduce drilling costs by 30%. Wetting Agents Improve Drilling Efficiency Much of the interest in the use of wetting agents to improve drilling efficiency is the result of an observation made by Rehbinder, Shreiner, and Zhigach.1 These investigators postulated that drilling creates a region of increased crack formation directly below the bit and that a circulating medium that wets the rock will also penetrate the micro- cracks of the predestruction zone. Increasing the molecular affiinity (wetting ability) of these circulating media for the surface of the rock helps the deformation and destruction by softening the rock in the zone of increased crack formation. In this manner, the hardness or strength of the rock is decreased as the medium wets the rock in the predestruction zone. This is known as the "Rehbinder effect." Rehbinder's work has prompted many investigators to examine the relationship between the use of additives and the mechanical destruction of rock. Engelmann, Terichow and Selim reported that the maximum penetration of the rock by a diamond point in a solution environment was at the isoelectric point of the mineral and solution interface.2 Improvement in rock breakage with the use of additives was observed by Frangiskos and Smith.3 Joris and McLaren suggest that additives having a lower surface tension than water will also be more efficient in cooling the diamonds.4 Additives help remove fine cuttings from the face of the bit and improve efficiency. The latter two authors also report an improvement in impregnated bit life and penetration rates with the use of soluble oil additives. All of these investigations were initiated in the hope of discovering what economic benefits will accrue with the use of additives.

Jan 10, 1969