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By R. B. Porter, R. P. Porter, R. A. Lothrop

Changes became necessary in dredging methods employed in Idaho through passage of the Dredge Mining Protective Act (1954). Among other provisions, the law requires dredge operators to construct settling ponds of sufficient capacity and character to reasonably clarify the water used in the mining process before such water is discharged into the stream. Porter Bros. Corp., a placer mining company with many years operating experience in Oregon and Montana, became interested in strategic mineral placers in Idaho in 1950 when it was learned that prospectors had discovered a radioactive mineral deposit in Bear Valley Creek, 95 miles northeast of Boise. The company acquired mining leases and proceeded with exploration and development work on the property. After extensive research had resulted in the determination of successful separation processes, contracts were negotiated with the federal government and deliveries of columbium-tantalum and uranium concentrates commenced in 1956. The mining operations are located in a primitive area of Idaho among salmon spawning grounds and crystal-clear mountain trout streams. To avoid involvement in a very controversial issue, it appeared advisable for the company to develop water treatment procedures exceeding those requirements stated in the Idaho Dredge Mining Protective Act. Operation: The company operates one 6 cu ft continuous bucketline dredge and one 4 1/4 cu ft continuous bucketline dredge on the property. The dredges are jig-equipped, with feed being screened to 3 in. by trommels. The screening and gravity concentration methods satisfactorily separate the heavy minerals from companion clays, sand, and gravel. However, this separation of the heavy minerals requires water from the dredge pond with a minimum content of silt and colloids; therefore, water for dilution is added continuously to the dredge pond to suppress solids buildup. Discharge of this highly turbid water to maintain the proper pond level would ultimately result in an excessive silt load in Bear Valley Creek. To prohibit the turbid pond water from flowing directly into Bear Valley Creek, it was necessary to isolate the dredging area. Main by-pass canals were constructed along each side of the dredge pond and numerous secondary canals were dug for diverting seepage and snow runoff. One by-pass canal, extending more than two miles along the west side of the valley, diverts the main stream as well as tributaries entering from the west; a canal east of the dredge area diverts streams entering from that direction. At the beginning of operations in 1956, the dredge pond effluent was filtered through tailings and settled by use of coagulents in a series of lagoons. The filtrate was then discharged directly into the stream. Although this procedure gave satisfactory results in conformance with the state law, ice buildup and lagoon freezing hindered the efficiency of the process during periods of low temperature. For this reason, testing began in 1956 on a water treatment process that would operate efficiently under the extreme weather conditions encountered in Bear Valley. Development of Water Treatment System: Porter Bros. Corp. established the following requirements for effective continuous treatment of dredge pond effluent to the stream which, at low flow conditions, effluent to the stream which, at low flow conditions, would not result in a turbidity exceeding 25 ppm in the stream, 2) produce a sludge sufficiently dense to minimize disposal area requirements, 3) be semi-portable to follow dredge movements, 4) be capable of operating at low temperatures, and 5) be capable of handling a variety of capacities and turbidities.

Jan 1, 1961

By Warren Weaver

Some of the advantages of the inductive method of electrical prospecting were emphasized in a paper by Dr. Max Mason. Since this emphasis was misunderstood by some to indicate a too exclusive interest in inductive methods, we are especially happy to help correct this impression by reporting on some of our work on surface potential methods. Earth Currents and Surface Potentials When two electrodes, A and B, are placed on the surface of the ground a distance d apart, and a 100-volt battery is connected across the elec- trodes, current flows from the positive electrode A to the negative electrode B. The current does not pass directly from A to B along the straight line joining these two points. In fact, a negligible amount of the total current chooses this direct path, and the flow actually takes place

Jan 1, 1929

By Porter W. Shimer

As is well known, cast-iron borings are a mixture of small particles of iron with more or less of finely divided graphite, separated from thc surfaces of these small particles during the process of boring. The amount of graphite thus mechanically mixed is, in all cases, quite large enough to cause serious difficulty when the problem is to obtain an average sample of a given lot of borings for carbon determination. This difficulty arises from the necessity of obtaining a uniform mixture of the heavy and comparatively coarse borings with the finely divided and light graphite, and of removing a sample for analysis without disturbing the uniformity of this mixture. It was first sought to overcome this difficulty by having the horings made very fine, so that they might have more nearly the size of the particles of graphite. It was not practicable, however, to secure this uniformity of size, since much of the graphite is in the form of the finest dust. At all events, the duplicate determinations of rarbon in these fine borings, made with every precaution by combustion in oxygen, frequently showed differences too large to be accounted for in arty other way than by imperfect sampling. Very coarse borings were also tried with the idea that the graphite separated from these large and heavy pieces would perhaps be inappreciable ; but it was found that quite enough was separated to vitiate the results. Various methods of mixing were tried, both in the bottle and on glazed paper ; but in all these mixtures it mas found that duplicate samples seldom colitained the same proportion of the mechanically mixed graphite; and when they did, there could be no certainty that it was the true proportion. All this was shown many times over by the failure of duplicates to agree closely, the differencheing sometimes so much as 0.20 per cent. It was finally clear that nothing was to be hoped from these methods. Even if we could secure a perfect mixture containing in every part its due proportion of graphite, it would run a great risk of being destroyed the moment a spatula was inserted to remove a sample: for the least agitation causes some of the graphite to fall through between the coarser borings.

Jan 1, 1886

By G. S. Hume

ACTIVE drilling operations for oil were carried on during the summer of 1923 in various parts of, western Canada, particularly in Alberta. During the early part of the summer, interest centered in southern Alberta, in the Coutts area, just north of the producing Kevin-Sunburst field of Montana; but on Nov. 14 a strike of oil by British Petroleums Ltd. at its well near Wainwright, 120 mi. east of Edmonton, diverted public attention to a new field. According to present estimates, this well has a possible production of from 60 to 100 bbl. a day; the oil is 15° Be. with an asphaltic base and is obtained from a sand at the depth of 2019-2036 ft. The oil stands at 1700 ft. in the casing and there is sufficient gas pressure to cause it to flow when the well is opened. The oil horizon is in a sandstone in rocks of Colorado age. It is known that there is a terrace structure of which the western edge extends in a northwesterly direction from the vicinity of Hardisty to Viking, where it probably swings more to the north. At Viking a small dome-like structure on this terrace gives rise to an important gas field. Wainwright lies directly northeast of Hardisty. The exact structure in the Wainwright field is unknown. At Fabyan, 6 mi. northwest of Wainwright, the Imperial Oil Co.1 last year brought 1n a large gas well estimated at 14,000,000 cu. ft.; the escaping gas sprayed a small amount of heavy black oil over the derrick. The gas was obtained at a depth of 2727 ft., deeper drilling encountering a water sand. The results of drilling in the Wainwright field are encouraging for future development.

Jan 3, 1924

By John Garcia

THE presence of carbon de terre along the banks of the Illinois river was noted by the members of the Joliet and Marquette expeditions in 1673, and that may be referred to as the birthday of coal in the Middle West. The march of progress in the majority of indus-tries radiating from Chicago-one of the phenomena of history-is due in no small measure to this same carbon de terre and to the development and exploita-tion of the vast coal resources, which nature in a generous mood spread so lavishly over almost the en-tire state. The geological records indicate that coal-bearing rocks underlie three-quarters of Illinois, in-cluding 85 of the 102 counties and the entire area is estimated at from 36,000 to 42,000 square miles. Not all of the coal in this great area may be mined under the conditions existing today; producers are now taking the "cream" since industry demands the best quality and the lowest cost, thereby forcing competition among operators, which, in turn, com-pels the development of mines in those areas where the coal may be most readily .won, leaving the coal that is more difficult and expensive to mine to pos-terity. This is not such a bad arrangement, since the engineers of succeeding generations will enjoy the advantage of the experience of their ancestors, where-by they should profit and know how to mine a 2-ft. seam with as much economy and dispatch as we today work coal of thrice that thickness. During the period between 1830 and 1850, Illinois coal-mining progressed from the art of scratching along the outcrop to the development of small mines, mostly slopes, drifts and shallow shafts, but the real progress in the industry was coincident with the con-struction of railroads.

Jan 2, 1927

By C. E. Sims

IN an earlier paper by Sims, Moore, and Williams: data were given to show that hydrogen contents of 0.3 relative volume (0.00033 wt pct), existing at the center of 4-in.-square cast-steel coupons, could be removed by aging at 400°F for 125 hr. At the end of that time, complete restoration of normal ductility for the steel was obtained. Replicate specimens of the same steel were aged at room temperature up to 555 days or .18 1/2 months. At the end of that time, the hydrogen content at the center had fallen to 0.13 relative volume or 0.00015 wt pet, but there was no perceptible change in the ductility. On the basis of experience with accelerated aging of 1-in. and 4-in. coupons and room temperature aging of 1-in. coupons, it was predicted that, some time after two years and when the hydrogen content has been reduced to about 0.10 relative volume, there would be some recovery of ductility. One set of three bars remained, and these were held for 1310 days, or more than three years. Then tensile test bars were cut from the center, and these bars were sampled for hydrogen analysis at the time they were broken. The sample specimens were cylinders % in. in diam x 1 1/4 in. in length. The data showed that in this time the average hydrogen content had fallen to 0.096 relative volume or 0.00011 wt pct, and the ductility had increased sharply. Elongation had risen from 10 to 17.3 pct, while reduction of area increased from about 16 to 27.5 pct. On the basis of these data, fig. 1 was drawn to replace fig. 15 of the earlier paper. Extrapolation of the curves of fig. 1 indicates that it would require a period of about 2200 days or approximately six years at room tem- perature to reduce the hydrogen to the minimum value and to recover full ductility in the center of the coupons. The aging process apparently involves the movement of hydrogen from the interior to the surface of the bar and evaporation at the surface. This flux of gas presumably follows some diffusion mechanism, and an effort was made to use the aging data, obtained at room temperature and at 400°F, to calcu-late coefficients of diffusion, in the hope that they might indicate the nature of the diffusion. The conclusion was reached. however. that the data were inadequate for such a purpose.

Jan 1, 1951

By J. E. Hilliard, H. E. Cook

It is shown that for systems having a miscibility gap the spinodal composition (c,) in the vicinity of the critical temperature (Tc) is related to the equilibrium composition (c,) by where cc is the critical composition. This expression is exart for the limit T — Tc and is a good approximation down to (T/Tc) - 0.9. If the miscibility gap meets the composition of the pure components THE recent theoretical treatment by cahn1,2 on spinodal decomposition of solid solutions has revived interest in methods of estimating the chemical spinodal, * i.e., the locus on a binary phase By use of the appropriate expression, the spinodal can be drawn on the Phase diagram almost by inspection with an accuracy comparable to that of lengthy calculations in which a free-energy function is fitted to the phase diagram. Satisfactory agveemenf is also obtained with spinodals comPuted from experimental free-energy curves. where G is the Gibbs free energy of the homogeneous solution and c the atomic fraction of component 2, the derivative being evaluated at constant temperature (T) and pressure (P). (These subscripts will hereafter be omitted from the partial derivatives.) If experimental measurements of G as a function of c and T are available in a single-phase region above the spinodal, then these can be extrapolated to obtain a series of metastable free-energy isotherms in the two-phase region, and from these isotherms a series of spinodal compositions can be calculated. Because the value of is very sensitive to experimental errors, an elaborate analytic procedure is required for

Jan 1, 1965

By V. F. Marsters

Peru has produced petroleum since the early seventies, the first work being in the Zorritos field, in the Province of Tumbes, adjoining Ecuador. In the early nineties, the Negritos field, in the Department of Piura, came into prominence, and by 1905 had attained an annual production of 335,160 bbl. The early development of the field was under the general direction of the London & Pacific Petroleum Co., but it is now handled by the International Petroleum Co. In 1900 and 1901, the Lobitos field became the scene of marked activity. In 1905, its total production amounted to 75,000 bbl.; it has continued to increase as has Negritos. From 1897 to 1902, there was prospecting in the region of La Brieta (or Fernandez), on the Mancora River, about 25 to 30 km. from the coast. Small production of a heavy oil was obtained from three different sands. So far as the author knows, no work has been done in that locality since 1902. There are thus four distinct fields in the north endof the Peruvian coastal plain. The, remaining productive locality of Peru is the Pirin or Pusi field, at the northwest end of Lake Titicaca, Department of Puno, in southern Peru. The first prospecting near Pusi was done by Brown Brothers, of Los Angeles, Calif., who obtained modest production about 1906; according to reports, activities ceased about 1914 or 1915. The maximum annual production was obtained about 1908, estimated at 76,000 barrels. Peru possesses two distinct geographic provinces in which we may look for the development of a larger oil industry; namely, the coastal plain province, and the inter-Andean plains.

Jan 7, 1922

There were present eleven Directors, the Secretary and Assistant Secretary of the Institute, and eleven guests. The Secretary, Bradley Stoughton, was appointed the representative of the Institute on the Board of. Directors of the American Bureau of Welding. A communication from a member of the Institute regarding simplified spelling was laid on the table. The following appropriations were made for the year. 1919: $250 to the Institute of Metals Division, $250 to the St. Louis Section, $100 to the Columbia Section. An invitation was received from the Western Society of Engineers to the Institute to use the facilities of that society during the A. I. M. E. Meeting in Chicago. The Bulletin of the Institute was presented to the French Congress of Engineers. There were elected twenty-eight members, eighteen associates, and three junior associates. The status of one member was changed from junior associate to associate. Four members were reinstated. An extension of time was granted to one member for payment of dues. The dues of four members on active military duty were suspended. Dues were remitted of four members who have been paying over thirty years, and who are each over seventy years of age.

Jan 5, 1919

By H. T. Shore, J. M. Schultz

A number of experimental rnethods—X-ray powder diffractometry, Laue photography, X-ray small-angle scattering, and transmission electron microscopy and dijfraction—have been utilized to examine the morphology associated with precipitation from the terminal, g, solid solution of a Zn-1 pct Cu alloy. A significant age hardening was observed in a 1 pct Cu alloy. X-ray and electron diffraction results showed that the structural inhomogeneities associated with the hardening were isotructural with the matrix. The average size and shape of the inhomogeneities were deduced from the electron microscopy and X-ray small-angle scattering. The preprecipitates are hexagonal platelets some 300? in diam. and some twelve unit cells thick. The orientation of the platelets was deduced from Laue photographs and electron diffraction. The platelet plane is (0001). When a large amount of pre-precipitation is present in a localized volume the new lattice is often disoriented by a rotation about (0001) of of the matrix. WhILE dilute Zn-Cu alloys have been commercially important for some 50 years, relatively very little is known metallographically about this material. The "Zilloys", zinc with about 1 wt pct Cu and sometimes a small addition of magnesium, are used to produce rolled zinc which is harder and stronger than that produced by other rollable zinc alloys.' According to the phase diagrams of the zinc-rich side of the Cu-Zn system, such dilute Zn-Cu alloys should age-harden;2-5 the solubility of copper in zinc, g-phase, at 424°C is 2.68 pct, while at 0°C it is only to 0.3 pct. However, the published literature on the aging of this system appears to be limited to a documentation of the contraction of 1, 2, and 3 pct Cu alloys aging at 95°c,6 and an attempt to measure changes in lattice parameters during aging.' In the latter work, no lattice parameter changes were detected, although a broadening of the highest-angle lines was detected and considerable diffuse scattering was observed. Micro-structural investigations have been limited to the latest stage of aging, wherein Widmanstatten precipitates are formed.3,47 These alloys are of interest for still another reason. The two most zinc-rich phases in the Cu-Zn system, 77 and E, are both hcp. Moreover, the change in a, between 17 and t for a 1 wt pct Cu alloy is onlv 3.64 -,~ct: the change in Co is 12.0 ict. It would be anticipated that precipitation in such a material might occur through metastable phases or G.P. zones with epitaxy along mutual 0001 planes. The goals of the present work are aimed at partially filling the void of knowledge concerning the early stages of precipitation from the g phase. In particular, we have attempted to document the magnitude of the age hardening of this system and to determine the size, shape, and orientation within the matrix of the elements of precipitation in an early stage of condensation. EXPERIMENTAL A) Specimen Preparation. Specimens were prepared In two somewhat different ways, one method being used for X-ray Laue and diffractometer measurements, optical microscopy, and Rockwell hardness measurements and the other used for electron microscopy and X-ray small-angle scattering. In the first case zinc and copper in the proper proportions to yield a 1 wt pct Cu alloy were melted together in a closed graphite crucible. Castings so made were free of apparent segregation or oxidation. The castings were then solution-annealed at 400°C for several days and then quenched in water to room temperature. Filings of portions of the specimens were made for use as X-ray powder diffractometry specimens. The electron microscope material was made as follows. Castings were made under vacuum with copper powder placed inside a hollow zinc cylinder to insure good contact of the materials. These 1 wt pct Cu pieces were then rolled to 0.1 mm with an intermediate anneal in vacuo. The rolled sheets so formed were then annealed for about 6 hr at 225°C. Finally the specimens were electropolished slowly until thin enough for transmission electron microscopy. The polishing is discussed in greater detail in the Results section. B) Measurements. X-ray measurements of three types were performed. A G.E. XRD-5 diffractometer was used to examine powders of the alloy for identification of second-phase material. A Kratky small-angle camera, also operating from a G.E. tube, was used to investigate the sizes of small precipitate particles. In both cases, nickel-filtered copper radiation was utilized. Finally, individual grains of the large-grained castings were examined in the back-reflection Laue geometry. Electron microscope studies were carried out with a J.E.O.L. Model 6A instrument. RESULTS A) Hardness Measurements. Hardness measurements performed at room temperature on the large-grained polycrystalline specimens showed a hardening which was essentially complete in 3 hr. Fig. 1 shows a typical plot of hardness vs aging time. The relative magnitude of the ultimate hardening varied from run to run between 150 and 200 pct of the value for the material immediately after quenching from the solution anneal. Most probably the variations reflect small changes in the time taken to remove the specimen from the vacuum furnace after the solution anneal.

Jan 1, 1969

By Eugene Stephenson

IN most instances the fluids produced from underground reservoirs have been described as they appear at the surface, and usually it has not been necessary to distinguish between surface and reservoir phases. More recently it has become imperative to recognize the fact that changes in phase may occur between the reservoir and the receiving unit. The simple terminology of "wet" and "dry" gases and "crude petro-leum oil" served our needs fairly well in the shallow, low-temperature and low-pressure fields. It has been left to the legislatures, regulatory com-missions, and courts to decide whether a field is or was a gas field, an oil field, or both. This they have done by direct definition and also by implication. For example, in Texas:1 (d) The term "gas well" is any well (a) which produces natural gas not associated or blended with crude petroleum oil at the time of production, or (b) which produces more than one hundred thousand (100,000) cubic feet of natural, gas to each barrel of crude petroleum oil from the same producing horizon, or (c) which produces natural gas from a formation or producing horizon productive of gas only encountered in a well bore through which crude petroleum oil is also produced through the inside of another string of casing. (e) The term "oil well" is any well which produces one (1) barrel or more of crude petroleum oil to each one hundred thousand (100,000) cubic feet of natural gas.

Jan 1, 1938

By T. S. Lovering

The Moffat tunnel passes through the continental divide about 50 miles west of Denver, Colo., on the Denver & Salt Lake R. R.: It is 16 ft. wide, 24 ft. high, and 32,383 ft. long, a distance of a little more than 6 miles. The advantages accruing from its construction may be briefly summarized as follows: The tunnel eliminates 27 miles of grade averaging more than 3.5 per cent. and actually running well over 4 per cent. in many places, and changes the steepest grade from 4.5 to 2 per cent. It reduced the peak of the railroad from 11,660 to 9249 ft. which enables one engine to pull four times as much freight as it could before the tunnel was built. If the Denver & Salt Lake R. R. completes its line, this road will shorten the distance between Denver and Salt Lake City by 200 miles and will have no steeper grades than the lines now connecting the two cities. The proposal to drive the tunnel through the divide dates back about 25 years and D. H. Moffat, who was the leading spirit in the organization of the Denver & Salt Lake R. R. spent much of his time and energy in efforts to raise money for the tunnel that bears his name. He was unsuccessful and died before the work was started. In 1920 an effort was made to obtain state legislation favoring a bond issue to finance three important railroad tunnels in Colorado but the measure was defeated, largely through the efforts of the citizens of the region near Pueblo. A few years later devastating floods caused the Pueblo voters to seek relief from the state and at this time they withdrew their objection to the tunnel bond issue. As a result, a $6,720,000 bond was issued to finance the Moffat tunnel. Construction bids were so high that the work was finally allotted on a scheme analogous to a cost-plus basis. The contract was awarded to Hitchcock and Tinckler, who are paid a fee of $140,000 for driving the tunnel. All bills are paid by the Moffat Tunnel Commission. The contract was let Sept. 19, 1923, and Hitchcock and Tinckler agreed to complete the work by July 19, 1927. In the event of finishing before this date they were to be given a bonus of $1000 a day and

Jan 1, 1928

By R. S. Lewis

The Utah field to which the name Book Cliffs is applied runs in a northeast direction from Mt. Hilgarde, in Sevier county…

Jan 1, 1915

By David A. Keys

The actual procedure in estimating depth of overburden from magnetic observations made on the surface will vary with the form of the deposit and any theoretical discussion will apply only so far as the form of the deposit conforms to the mathematical premises on which the theory is based. Since the shapes of natural deposits in the field cannot be expressed rigorously in mathematical form, the best that can be done is to assume some simple form and deduce results. Fortunately many small variations in form produce only slight changes in the estimated depth of overburden, therefore the methods have a definite practical value. For the theoretical treatment, magnetic ore deposits may be divided roughly into three classes, depending upon whether the magnetic anomalies may be considered to arise from (1) a single magnetic pole, (2) a dike or (3) a magnetic doublet. Particular cases, falling under one or other of these classes, have been discussed by different authors.1"4 In general, it may be stated that when the magnetic effects as measured on the surface are due only to one pole of the body, the other pole being so remote that its effect may be neglected, the resultant anomaly F at any point will vary as the inverse square of the distance r of the point from the pole, which may be expressed mathematically by F = k/r2, where k is a constant. When the deposit occurs in the form of a long, thin dike, the resultant anomaly will be of the form F = k'/r and when the deposit is in the shape of a lens, so that both poles have an appreciable effect on the surface, the result will be similar to that caused by a magnetic doublet, and the form will be F = k'/r3. The particular class under which a deposit falls may be deduced from the results of the magnetic survey. The second class is readily found, but there may be difficulty in deciding between the first and third. Isody-namic contours of both the vertical and horizontal anomalies will often be a good guide in making a correct decision. The correctness of the theoretical calculations may be checked in two ways. The first is to make laboratory models of various known shapes and pole distributions, to calculate the anomalies to be expected

Jan 1, 1940

By David A. Keys

The actual procedure in estimating depth of overburden from magnetic observations made on the surface will vary with the form of the deposit and any theoretical discussion will apply only so far as the form of the deposit conforms to the mathematical premises on which the theory is based. Since the shapes of natural deposits in the field cannot be expressed rigorously in mathematical form, the best that can be done is to assume some simple form and deduce results. Fortunately many small variations in form produce only slight changes in the estimated depth of overburden, therefore the methods have a definite practical value. For the theoretical treatment, magnetic ore deposits may be divided roughly into three classes, depending upon whether the magnetic anomalies may be considered to arise from (1) a single magnetic pole, (2) a dike or (3) a magnetic doublet. Particular cases, falling under one or other of these classes, have been discussed by different authors.1"4 In general, it may be stated that when the magnetic effects as measured on the surface are due only to one pole of the body, the other pole being so remote that its effect may be neglected, the resultant anomaly F at any point will vary as the inverse square of the distance r of the point from the pole, which may be expressed mathematically by F = k/r2, where k is a constant. When the deposit occurs in the form of a long, thin dike, the resultant anomaly will be of the form F = k'/r and when the deposit is in the shape of a lens, so that both poles have an appreciable effect on the surface, the result will be similar to that caused by a magnetic doublet, and the form will be F = k'/r3. The particular class under which a deposit falls may be deduced from the results of the magnetic survey. The second class is readily found, but there may be difficulty in deciding between the first and third. Isody-namic contours of both the vertical and horizontal anomalies will often be a good guide in making a correct decision. The correctness of the theoretical calculations may be checked in two ways. The first is to make laboratory models of various known shapes and pole distributions, to calculate the anomalies to be expected

Jan 1, 1940

By R. C. Earlougher

Based on laboratory tests conducted with the use of fresh core samples as well as a considerable amount of field data obtained from numerous water floods in northeastern Oklahoma, it appears that for any given oil saturation there is a critical maximum velocity above which the oil-recovery efficiency falls off very rapidly. In effect, when a water flood is operated above this critical velocity, the injected water-oil ratio rises extremely fast, thus shortening the economic life of the flood and reducing the ultimate oil recovery. This critical velocity apparently varies considerably with the percentage of oil saturation of the sand, so that in effect the higher the oil saturation at the beginning of a flood the higher the velocity that can be used successfully. In reviewing several of the earlier floods in the Mid-Continent area, it is concluded that most of the failures were due to two things: (I) too low an oil saturation, such as 30 per cent, and (2) too high water-injection rates, Although considerably more field data are necessary to establish definite limits, it would seem that the proper field injection rate for a 330 by 330 or 440 by 440-ft. spacing varies from approximately I bbl. per foot of sand per day where the oil saturation is as low as 30 per cent up to 5 bbl per foot of sand per day when the oil saturation is as high as 45 to 50 per cent, Introduction With secondary recovery by water-flooding receiving more and more attention throughout the industry, a greater working knowledge of multiphase flow under field conditions becomes more and more necessary A great deal of research has been carried on in highly idealized laboratory conditions, from which certain trends have been indicated, but with few exceptions no direct application to field use has been reported. widely varying conclusions have been drawn from the mass of idealized laboratory experiments and often this divergence apparently was due to the neglect of connate or interstitial water. Since interstitial water is such an important factor in water-flooding operations, it then follows that any laboratory flooding experiment must necessarily take it into account; and since it is difficult to set up laboratory models to allow for interstitial water, the next best procedure is to use fresh core samples for such tests. Even this procedure has its difficulties, inasmuch as it is possible to run only one flooding test on each sample, as each sample differs somewhat in character from all other samples. However, this disadvantage can be overcome to a large degree by the use of an extremely large number of samples. The next question that arises is: "IS it possible to get uncontaminated core samples having a true oil and water saturation like that existing in the reservoir?" If the sand under consideration is still in the primary stage of production, with a normal or relatively high amount of gas still in solution in the oil, probably it is not possible to get a nonflushed core. On the other

Jan 1, 1943

By R. C. Earlougher

Based on laboratory tests conducted with the use of fresh core samples as well as a considerable amount of field data obtained from numerous water floods in northeastern Oklahoma, it appears that for any given oil saturation there is a critical maximum velocity above which the oil-recovery efficiency falls off very rapidly. In effect, when a water flood is operated above this critical velocity, the injected water-oil ratio rises extremely fast, thus shortening the economic life of the flood and reducing the ultimate oil recovery. This critical velocity apparently varies considerably with the percentage of oil saturation of the sand, so that in effect the higher the oil saturation at the beginning of a flood the higher the velocity that can be used successfully. In reviewing several of the earlier floods in the Mid-Continent area, it is concluded that most of the failures were due to two things: (I) too low an oil saturation, such as 30 per cent, and (2) too high water-injection rates, Although considerably more field data are necessary to establish definite limits, it would seem that the proper field injection rate for a 330 by 330 or 440 by 440-ft. spacing varies from approximately I bbl. per foot of sand per day where the oil saturation is as low as 30 per cent up to 5 bbl per foot of sand per day when the oil saturation is as high as 45 to 50 per cent, Introduction With secondary recovery by water-flooding receiving more and more attention throughout the industry, a greater working knowledge of multiphase flow under field conditions becomes more and more necessary A great deal of research has been carried on in highly idealized laboratory conditions, from which certain trends have been indicated, but with few exceptions no direct application to field use has been reported. widely varying conclusions have been drawn from the mass of idealized laboratory experiments and often this divergence apparently was due to the neglect of connate or interstitial water. Since interstitial water is such an important factor in water-flooding operations, it then follows that any laboratory flooding experiment must necessarily take it into account; and since it is difficult to set up laboratory models to allow for interstitial water, the next best procedure is to use fresh core samples for such tests. Even this procedure has its difficulties, inasmuch as it is possible to run only one flooding test on each sample, as each sample differs somewhat in character from all other samples. However, this disadvantage can be overcome to a large degree by the use of an extremely large number of samples. The next question that arises is: "IS it possible to get uncontaminated core samples having a true oil and water saturation like that existing in the reservoir?" If the sand under consideration is still in the primary stage of production, with a normal or relatively high amount of gas still in solution in the oil, probably it is not possible to get a nonflushed core. On the other

Jan 1, 1943

By Henry Louis

Henry Louis, Newcastle-upon-Tyne, England (communication to the Secretary*).—In this paper Mr. Simons derives the various forms of revolving slime tables, of which the Harz and the Linkenbach tables are typical examples, from the old rectangular or box buddle. This I believe to be an error, at any rate if Mr. Simons attaches the same meaning as I do to the ((evolution" of a dressing appliance. By the '(evolution" of such an appliance I understand the progressive development and improvement of an appliance acting on a definite principle, such improvements having usually for their object the economy of labor in working the same, or the increase of its capacity; when an entirely new principle is introduced, I no longer look upon this as evolution from the old type, but as the origination of an independent type of appliance. The box buddle was no doubt the predecessor of the old Cornish round buddle, which was evolved from it with the object of saving the labor required to work the box buddle; both machines are horizontal-current separators, in which the separation of sands of different densities is effected by their differential rates of fall in a horizontal current of water of considerable depth. These appliances, though well suited to sands, are for obvious reasons not adapted to the treatment of slimes. The revolving tables of the Harz and similar types, on the other hand, act on the principle which I have called separation in thin films of water, and which Mr. Simons calls the film sizing principle, in which the resistance of the surface over which the pulp flows plays an essential part in determining the separation of the particles, and which is well suited to the treatment of slimes. Unlike the last principle, it will not work in deep bodies of water and cannot be used where considerable depth of material accumulates in the appliance, as in the box buddle and round buddle. As I have shown in my book, The Dressing of Minerals, p. 326, these revolving tables are a development of the appliance known variously as the flat buddle, flat table, or frame, the last name, which is the old Cornish one, being the one that I personally prefer. These primitive appliances, as well as the continuous-acting round tables described by Mr. Simons (his Figs. 10 et seq.) all work on the principle of separation in thin films, and are all adapted for the treatment of slimes; his buddles and round tables (Figs. 1 to 9) do not work upon this principle, and should therefore be sharply differentiated from the former. The evolution in each case of the continuous acting, more or less automatic, circular appliance from the primitive, intermittent, hand-worked, rectangular appliance has proceeded upon strictly parallel lines. The question of the evolution of the respective types involves a point of some importance as regards the principles of ore dressing.

Jan 1, 1915

By Ward C. Smith

The industry of producing and processing boron compounds is called the borax industry because the chief product is borax, the decahydrate of disodium tetraborate. For the same reason, it is common to speak of borax mining. Reference to borate mining also is common, and while appropriate where it emphasizes the diversity of borate minerals that are mined in various countries, it is rather unsatisfactory where used in a general sense, because it seems to exclude the important production of borax from brine at Searles Lake, California, and of boric acid from steam vents in Tuscany, Italy. The terms "boron industry" and "boron mining" might seem more comprehensive, but are little used, and this is fortunate because they would be misleading-the element boron is manufactured only in small amounts for special uses, and it is not found free in nature. In most occurrences, boron is combined with oxygen and is in a borate or borosilicate material. The history of the modem borax industry starts with the introduction into Europe of borax from Tibet in the 13th century, about the time of Marco Polo, if not actually by him. The discovery that borax has unique value as a flux in metal soldering and ceramic glazing must have been made at some unknown time much earlier. As a rule, any mineral that has been used so long that its early history is lost must occur in deposits that are easily recognized and worked, and this is undoubtedly true of borax in Tibet. According to meager accounts,9 the borax occurs there in arid mountain basins as surficial crusts that coat the ground about thermal springs and seeps of mineralized water, and as coarser crystals in the bottom muds of shallow pools and lakes. Much the same essential features of surface exposures and minerals easy to recognize and recover characterize most of the deposits later found and worked elsewhere. The borax industry at the present time is faced with rising demands for its products, and consequently is increasing its productive capacity and appraising its borate resources.18 The areas that contain the known borate deposits are most likely to yield additional production, hence their distribution in the world is of interest, and is summarized later in this chapter. Mineralogy The mineral raw materials used by the borax industry include various borates mined in several countries, borax extracted from brines at Searles Lake in California, and boric acid extracted from the steam of vents in Tuscany in Italy. The hydrated borates[$] of chief commercial importance are listed in Table 1, which also shows their chemical composition. The properties of only the four most important borates are summarized here, but detailed descriptions of the borates and the minerals commonly found with them can be found in mineralogy textbooks.41 Ulexite generally forms clusters of silky fibers rather than large individual crystals. A

Jan 1, 1960

By M. C. Fuerstenau, R. B. Bhappu

The response of beryl to sulfonate flotation was examined. The dependence of flotation recovery on sulfonate concentration, pH, and the absence or presence of various ions is also demonstrated. The response of quartz and feldspar to sulfonate flotation at various values of pH is given to. show the conditions necessary for selective separation. Finally, beryl was successfully concentrated from a natural ore using a technique devised from experimental observations on systems of pure minerals. With the possible exception of quartz, the flotation characteristics of silicate minerals are rather poorly understood. This is due in part to the com- plexity of the mineral systems themselves and in part to an insufficient amount of flotation data. The complexity of the systems arises from the wide range of chemical composition that the silicate minerals can assume. This is reflected in the variability of such physical properties as hardness and cleavage. Although the chemical composition of silicate minerals can vary considerably, a general grouping can be accomplished conveniently on the basis of the assemblage of SiO4 tetrahedra in all the silicates. That is, it has been shown that six basic groups can be obtained, depending on the arrangement of oxygen sharing between adjacent silicon atoms (or substituted aluminum). When all four oxygen atoms are shared, a framework structure such as quartz or feldspar is obtained. When three oxygens are shared, infinite sheets are obtained as in the micas and clays. When two oxygen atoms of the tetrahedra are shared, infinite chains are obtained, such as those in

Jan 1, 1963