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By N. S. Keith

No one of the live subjects of the day, to which the attention of the mining engineer and metallurgist should be turned, is of greater practical interest to him than electricity in its applications to various mechanical, chemical, and metallurgical operations.. The object of this paper is to call the attention of my fellow-members and associates of the Institute to various new, as well as comparatively old, developments in the science and art of electricity which seem to promise results of advantage. Too many of the comparatively old applications have been neglected by the mining engineer, which, if he had given them a place among his appliances, would have assisted him greatly. The telegraph may be noticed as one. Its use is, however, confined to a person having skill in the manipulations of the key, the reading of the alphabet, and familiarity with the sounder. One of the simpler forms—the call-bell—has a range of application far greater as to distance and convenience than the old wire-pull, or the hoarse voice of the windlass-man or the bucket-dumper. A few Leclanche cells, two or more electric bells, and a mile or more of mire judiciously placed will put the superintendent, at his office, in communication with the foremen of his mills and mines, so that by the aid of a code of signals, great advantages may be gained without necessitating a knowledge of the Morse alphabet, or of the mechanical voice of the sounder. The telephone furnishes a means of communication be-

Jan 1, 1882

By Francis Foley

Small cracks in a plane normal to the axis of steels are found to be prevalent around the water hole of drill steels that have been in service for an unknown period of time. Cracks are not found on the exterior surface of the steels nor to any noteworthy extent even in the water holes of new drill steels. Undulations and serrations are found in the surface of the water hole in new steels; it is in the bottom of such defects that cracks appear to develop in used steels. The occurrence of the more serious of these cracks at the point in the steel to which it has been heated for forging or hardening is thought to account to a great extent for failures in that region. DURING the past, year, we have investigated the cause of 88 per cent, of the failures by breakage near the bit end of some 1-in. hollow, hexagon, drill steel used in a metal mine. This breakage in the region of the bit end of the steel was peculiarly interesting because we have been led to believe that breakage is most prevalent at the shank end of drill steels near the place where the steel is gripped in the chuck of the machine. Records from the mine showed, also, that the breakage was much more frequent in the short lengths of large gage than in the longer steels; this is shown graphically in Fig. 1. Because the shorter lengths of steels are usually those that have been made from broken pieces of long steels or from steels that have worn down in service, rarely being made from new stock, those who are wont to suspect steel of tiring and crystallizing in its old age through fatigue are quite apt to see in this instance an argument in favor of their idea. As usual, a careful examination of these steels reveals defects of a character hardly to be overlooked in favor of such a cause. The steel in question was rolled with a sand core and was of the usual drill steel composition: Carbon 0.85 per cent., manganese 0.60 per cent., silicon 0.25 per cent., phosphorus 0.02 per cent., and sulfur 0.02 per cent., with the exception that in some specimens there was vanadium, not exceeding 0.20 per cent.

Jan 3, 1924

By M. Van Siclen

THE outstanding fact in connection with dust disease in the United States at present is the growing recognition of its seriousness by state officials and by the more progressive operators of mining, metallurgical and allied industrial plants. The same may perhaps be said of labor in some of its better organized centers, but the average independent non-union workman continues, as of yore, to suffer the toll of disability and even of death from dust inhalation without realization of the source of his ill-being. Progress in the betterment of the handling of sufferers from dust disease and of the conditions creating dust hazards in mining and allied industries is pursuing a course similar to that of the now widespread campaign against accidents, in which the risk is more obvious, more severe, and was naturally recognized sooner. The coming on of dust disease is generally relatively slow and its immediate effects not infre-quently masked by or attributed to other diseases. Marked exceptions to this general rule have occurred in districts where the dust is particularly pernicious, such as the Rand and Joplin; yet such exceptions, unhappy in themselves, opened the eyes of medical men, and of those in other localities charged with the responsibility for the welfare of industry, to the much more widespread if less spectacular hazard existing from the inhalation of dust in all rock-excavating operations and all industrial operations creating inorganic dust, whether it be crushing and grinding, sand-blast-ing, granite-cutting, or what not. Advancement to date in the United States in prevention and treat-ment has been slow, yet the record shows that quantitative methods for determining the degree of hazard and means for decreasing it were being developed as far back as 25 years ago; and that more rapid progress may be looked for from now on. In 1908, in this country, F. L Hoffman?(1) discussed the mortality from consumption in dusty trades, especially brass foundries; and in 1913 E. R. Hayhurst(2) described the effects of inhalation

Jan 1, 1933

By J. C. Danko, R. D. Stout, A. H. Holtzman

The deformation characteristics of pearlite have been studied by light and electron microscopy.1,2 In the electron-microscopic work, deformation was found to take place by 1) ferrite slip which is parallel to the lamellae, 2) slip transverse to the lamellae with both cementite and ferrite deforming, and 3) ferrite-cementite interfacial slip. The transverse slip gives a step-like appearance to the lamellae in light microscopic work. It was thought that spheroidization of deformed pearlite would commence at the regions of maximum cementite deformation, the "stepped" areas. Although there is no possibility for seeing slip in the microstructure if the specimen is polished after deformation, the step-like appearance of the lamellae clearly indicates the transverse deformation. Thus, the areas of cementite deformation are apparent after polishing and the effect of deformed areas on spheroidization may be studied by the usual metallographic techniques. This note reports the result of a metallographic investigation which substantiates that spheroidization begins in the "stepped" areas. An AISI 1080 steel was normalized, re-austeni-tized at 1040°C, and isothermally transformed at 700 ± 4°C for 4 hr. Cubes, 5 mm to a side, were compressed between parallel plates to strains of 20, 40, and 50 pct. After deformation, specimens were heated to 600, 650, and 700°C; withdrawn at increasing time intervals and examined metallo-graphically for the percentage and distribution of spheroidite. The percentage of spheroidite was determined by lineal analysis. A micro structural region considered as spheroidized was one in which a lamellar skeleton was not distinguishable. Table I gives the times necessary for 95 pct spheroidization for each condition of strain and annealing temperature. Fig. 1 shows the microstructure of coarse pearlite compressed 20 pct, then polished and etched. Here the lamellae form a step by bending at two

Jan 1, 1959

By J. H. Collier

The mother lode, or mineralized belt, at Angels, in Calaveras county, California, is 3 miles wide. At least, a region of that width has been, and is being, prospected which has shown considerable mineralization. The lode proper divides into three lodes, or groups of veins, at this point. On all of these branches, mines have been operated with more or less success.

Jan 1, 1900

* A demonstration pipeline for transporting coal will be constructed by Pittsburgh Consolidation Coal Co, at the Georgetown strip-mining operation near Cadiz, Ohio, The 12-in., 17,000-ft line, special crushing and preparation equipment, and pumps especially designed for the operation will cost about $550,000. A slurry of fine coal and water will be fed into the line and moved through it under pressure. * Sulphur resources in the U.S. are being rapidly exhausted with no new major deposits being found, This common mineral may become one of the most strategic items during the next five years. Recovery of sulphur from pyrites is being considered in case of an emergency. Already the British have adopted stringent measures to conserve sulphur supplies.

Jan 3, 1951

By A. H. Larson, L. G. Twidwell

The influence which Au, Ag, Sb, Bi, Sn, and Cu have, both individually and collectively, on the activity coefficient of sulfur in liquid lead at 600"C zuas studied by circulating a H2S-Hz gas wlixture over a specific lead alloy until equilibrium was attained. Subsequently, the H2S concentration in the equilibrium gas mixture and sulfur concentration in the condensed phase were deterruined. The elements gold, silver, and antinzony (above 8 at. pct) increased the activity coefficient of sulfur. Bismuth had no apparent effect. Tin (above 3 at. pct) and copper decreased the coefficient. The influence of an individual element, i, on sulfur is best reported as the interaction parameter, riS, which is defined as The values o these first-order interaction zus are: ESzu = —55.0. These interaction parameters are used to predict the activity coefficient of sulfur in six fouv-component alloys and one seven-component alloy. Comparisons are made with direct experimental determinations. INTERACTIONS in dilute solution have been studied by many investigators. Most of the experimental work has been confined to solute-solvent interactions in simple binary systems and solute-solute interactions in ternary systems. Dealy and pehlke"~ have summarized the available literature on activity coefficients at infinite dilution in nonferrous binary alloys and have calculated from published data the values for interaction parameters in dilute nonferrous alloys. Interaction parameters are a convenient means of summarizing the effect of one solute species on another in a given solvent. Only a few investigators have studied interactions of the nonmetallic element sulfur in a metallic solvent. They are as follows: Rosenqvist,~ sulfur in silver; Rosenqvist and Cox,4 sulfur in steel; chipman, sulfur in alloy steels; Alcock and Richardson,% ulfur in copper alloys; Cheng and Alcock,' sulfur in iron, cobalt, and nickel; Cheng and ~lcock,' sulfur in lead and tin. The only reported work on the Pb-S system in the dilute-solution region is that of Cheng and Alcock.' Their investigation involved a study of the solubility of sulfur in liquid lead over the temperature range 500" to 680°C. The results may be summarized by the following relationship: S (dissolved in lead) + Pb(1) = PbS(s) log at. %S = -3388/T + 3.511 Experimentally, it was found that Henry's law was valid up to the solubility limit of sulfur in lead, i.e., at 600°C up to 0.43 pct. Their investigation did not include the study of sulfur in lead alloys. More accurate calculations could be made in smelting and refining systems if activity coefficients of solute species could be accurately predicted in complex solutions. One of the objectives of this study was to compare the experimental data with the values calculated from the equations derived from models for dilute solutions proposed by wagner9 and Alcock and Richardson. A temperature of 600°C was chosen as the experimental temperature to attain reasonable reaction rates and to minimize volatilization of the condensed phase. EXPERIMENTAL Materials. The Pb, Au, Ag, Sb, Bi, Sn, and Cu used for preparation of the alloys were American Smelting and Refining Co. research-grade materials. All were 99.999+ pct purity except the antimony and tin which were 99.99+ pct. The initial alloys prepared for this study consisted of twenty-one binary alloys, eleven ternary alloys, and one six-component alloy. The constituent elements were mixed for each desired alloy and were placed in a crucible machined from spectrographically pure graphite. The crucible was placed in a vycor tube which was evacuated with a vacuum pump and gettered by titanium sponge at 800°C for 8 to 12 hr. After the gettering was completed, the chamber containing the titanium was sealed and removed. The remaining sample chamber was placed in a tube furnace at 800°C for 2 hr and quenched in cold water. The final operation consisted of homogenization of the alloy for 1 to 2 weeks at a temperature just below the solidus for the individual system. The resulting master alloys were sectioned into small pieces and a random choice made for individual equilibrations. Cobalt sulfide (Cogs8) used to control the gas atmosphere in the circulation system was prepared by passing dried HzS for 24 hr over a Co-S mixture heated to 700°C in a tube furnace. This material was then mixed with cobalt metal to give a two-phase mixture which, when heated in hydrogen to a particular temperature, produced a desired H2S/H2 gas atmosphere in the circulation system. A Cu2S-Cu mixture also used in this study was prepared in a comparable manner. Apparatus for Equilibrium Measurements. The experimental technique of this study required apparatus

Jan 1, 1967

By J. A. Hren, C. M. Wayman

RECENT investigators have noted anomalous behavior in the electrical resistivity of vanadium below room temperature. Rostoker and Yamamoto1 in studying the vanadium-oxygen system hypothesized that the body-centered-tetragonal phase existing from 15 to 34 at. pet O at approximately 800°K was really a low-temperature allotrope of vanadium that was stabilized by oxygen. In measuring the electrical resistance of cold-swaged vanadium rod over a range of temperatures, a small discontinuity was observed at approximately 240°K, supporting their notion of allotropy. However, the magnitude of the observed discontinuity was extremely small. Loomis and Carlson2 in studying the ductile-brittle transition in vanadium also made resistance measurements and reported a discontinuity near 200°K. More recently, White and Woods3 showed that the electrical resistivity from room temperature to approximately 100 °K was not linear and at variance with the Bloch-Griineisen law. Instead of finding a discontinuity, they observed a deviation from linearity below 200°K. In discussing their results they pointed

Jan 1, 1961

By M. T. Hepworth, W. B. Sample

HYDROGEN solubility and linear contraction measurements were made at constant temperature on an alloy of titanium of constant oxygen-to-titanium molal ratio but variable hydrogen content. A cylindrical specimen of titanium (0.25 by 1.6 in.) containing 0.75 at. pct 0 and less than 0.03 at. pct N was cast from a master button of iodide process titanium which had been alloyed with titanium dioxide. Four vacuum fusion analyses, which were made along the length of the cylinder after the hydrogen solubility studies were made, revealed a variation of oxygen content of less than 0.02 at. pct. The specimen was introduced into a quartz furnace tube, annealed and outgassedat 1050"~ for about 1 hr, and then held at 800" * 0.5" for about 30 hr, during which latter time experimental data were taken. The leak rate to the furnace chamber was not sufficient to contaminate the specimen during the run as determined by leak-rate studies and vacuum fusion analyses for oxygen and nitrogen before and after the runs. The furnace chamber was attached to a modified Sieverts apparatus used to introduce measured quantities of purified hydrogen to the specimen. A quartz pushrod transmitted changes in length of the specimen to a Chevenard dilatometer. The push-rod passed through a vacuum grease seal to the dilatometer which amplified motion of the rod by a factor of 319. During hydrogen addition, the pushrod did not contact the specimen. Measured quantities of hydrogen were added to the specimen and equilibrium hydrogen pressures recorded as a function of hydrogen content. The solubility data, which appear in Fig. 1, agree well with a separate investigation made with a different apparatus. The solubility limit of the hcp a phase appears as an abrupt discontinuity in slope at 3.4 at. pct H. The solubility plot has been extended as a dashed line at this discontinuity in order to emphasize the discontinuity. The hydrogen content at which bcc P appears is not clearly defined. An arrow indicates solubility data were taken upon hydrogen addition. Upon reaching the arbitrary maximum hydrogen content of the run, the quartz pushrod was pressed against the specimen in order to record the change in length with hydrogen removal. A pressure of about 100 g per sq cm was required to overcome the friction of the vacuum seal in order to obtain reproducible linear contraction data. The contraction ratio ~2/1", change in length divided by original length, was set equal to zero for the maximum hydrogen content. The relative contraction of the specimen was observed upon removal of hydrogen in the following manner. The system was opened to the pumps for a few seconds and an unknown quantity of hydrogen was removed. The system was then isolated from the pumps by closing a stopcock and allowed to return to equilibrium. When the temperature returned to 800°C, the pressure stabilized, and contraction ceased, measurements of contraction and pressure were made. The hydrogen content of the specimen was then deduced by measuring the equilibrium PIydrogen pressure and referring to the solubility plot. Linear contraction was then plotted against interpolated values of atomic percent hydrogen. The justification for this procedure is the established reversibility of the hydrogen equilibrium.' Uniaxial compression was assumed to have no effect on hydrogen pressure. The isothermal linear contraction data are plotted on Fig. 1. An arrow indicates data were taken upon removal of hydrogen. The solubility limits of the two phase a i /3 region can be identified by discontinuities ill slope of the dilatometric plot at 9.1 and 3.4 at. pct H, agreeing well with other studies.' Dashed extensions of the plots emphasize the discontinuities. Isothermal studies of expansion made upon hydrogen addition gave curves of much smaller slope and less pronounced discontinuities. A uniaxial compressive stress tends to accentuate volume changes in going from the more open bcc phase to the hcp phase.2 Incomplete data on ex-

Jan 1, 1962

By James Douglas

Though liberality is not supposed to be a prominent trait of the Scottish character, Canada owes to a Scotchman, Sir Wm. Macdonald, more than to any other of its people, not only wise ideas, but pecuniary help towards extending education: and another Scotchman, in New York, has sumptuously housed under one roof three branches of the engineering fraternity, of which we are one. Having thus created us members of the same family—for the metaphorical meaning of house and kinship is identical—Mr. Carnegie expresses more emphatically than even he could in words, that, by aff'ording facilities for closest intercourse, he invites the mechanical, electrical and mining engineers to participate in the freest interchange of idea and experience, and to correlate and combine the results of their studies and activities; and, being members of the same household, to banish reserve and secrecy. And now we, the members of the American Institute of Mining Engineers, meet as though we were at home in a neighboring country. For whether we meet in Canada, in England, or elsewhere, the Institute is always received as though no political or geographical divisions separated its members from those of congenial associations in the land of its host. In truth, the title which we have assumed claims for the sphere of our activities the whole American continent, regardless of such trifling details as boundary-lines. The fact that we meet to communicate each other's experience, to discuss our difficulties, and to seek each other's aid in solving the intricate problems that so often present themselves in the course of our professional life, is an acknowledgment of our individual helplessness; and therefore an argument for united effort. But no effort can be of any value if there is an underlying suspicion

Jan 1, 1908

By Arthur Lake

Within the past few months I have had occasion to visit and examine the area of country in Gunnison county locally called the Gold Belt and extending from the Cebolla river on the west to the head of Taylor Park and the Sawatch range on the east. The region including the "belt" may be hided topographically into two parts, a northern and a southern one. The former is characterized by lofty mountains and deep canons, with occasional parks and wide valleys. Most of it is included in the granitic system of the Sawatch range, with local patches of the Palaeozoic sedimentary rocks, more or less traversed by great bodies of porphyry and other eruptive rocks. The southern portion, on the other hand, is characterized by comparatively low, rounded hills of schist and sahistose gneisses, underlain by coarse, massive granite, which outcrops locally in small, and sometimes in large, patches. These hills also sometimes form table-lands by reason of overflows of lavas, such as andesitic breccia, rhyolite, trachyte and basalt. The leading geological feature is that of a schistose area of width and extent unusual for Colorado. These schists and gneisses are of pre-Cambrian age; but whether assignable to the Algonkian or to some older system has not been determined. The granite which occasionally outcrops from beneath these schists is, I think, of true eruptive character, since its mode of occurrence indicates a once molten, or at least highly viscous or plastic, condition. Thus, we may observe, included in its mass, numerous fragments of schist, almost like a coarse, volcanic breccia. Again, at its immediate contact with the schists, which often stand vertically upon it, the pediments of the latter are fused into the granite, and granite tongues and veins run up amongst the schists, as only a molten or viscous

Jan 1, 1897

By N. W. Wickersham, Ward B. Blodget, Roberts R. Boyd

The year 1926 has seen few radical changes or developments in methods of drilling and handling oil wells, but it has been a year of steady progress and development in deep drilling and production methods. Probably the outstanding development of the year was recognition by the directors of the American Petroleum Institute of the importance of natural gas in the production of oil, and the Institute directors' resolutions in December, 1926, regarding regulation of gas production with oil by state legislation. This matter is extremely important and will receive the attention of the industry in 1927. Advances in Drilling Equipment The history of the progress of deep well drilling is the solution of problems as they have confronted the operator. As the prospects for deeper production have become apparent, methods of penetrating the earth to greater depths have been devised. Rotary Equipment Improvements in the construction and in the methods of operation of rotary drilling equipment have practically caused elimination of cable tools in California for all but shallow work. The rotary drill, from 1910 when it began to be a practical factor in California, has been making steady advances, first displacing cable tools for drilling to the oil sands in proved fields and later displacing the cable-tool outfit entirely. With the perfection of machinery for taking core samples of the formation penetrated, the rotary drill has become generally used for wildcat work, continuous coring being practiced when desirable. Deep Holes The use of the rotary drill has made commercially feasible the opening of oil fields at greater depths than was considered possible with cable tools. Heavier equipment has been promptly supplied as occasion has

Jan 1, 1927

By T. Busch, R. A. Dodd

The solubility of hydrogen in pure iron and pure nickel, and of nitrogen in pure iron, has been determined and agrees well with earlier data. Nitrogen is insoluble in pure nickel and cobalt. The solubility of nitrogen in Fe-Ni alloys also confirms earlier- work. The solubility of hydrogen in Fe-Ni alloys increases non-linearly with increase in nickel content, but the solubility of hydrogen in Ni-Co and Fe-Co alloys reaches a minimum at 75 and 50 at. pet, respectively. The solubility of nitrogen in Fe-Co alloys decreases approximately linearly with increase in. cobalt content. Nitrogen is insoluble in Ni-Co alloys. Determined interaction parameters are in good agreement with predictions of Gokcen and Ohlani. THE solubility of hydrogen and nitrogen in liquid iron and iron alloys has been studied by various investigators.'-l' The method of solubility measuremerit due to Sievertsl is usually preferred when the vapor pressures of the liquid components are sufficiently small, but other techniques such as sampling the equilibrated melt and then analyzing by vacuum fusion have been used quite often. Previously reported data on the solubility of hydrogen and nitrogen in ostensibly pure liquid iron are summarized in Table I; certain of the quoted results were obtained by interpolation of the published data. Agreement between the various investigators is only fair, indicative of the experimental difficulties involved in obtaining gas solubility data. The only report found on the solubility of hydrogen in pure nickel is that of Sieverts.2 The solubility of nitrogen in iron-nickel alloys has received some attention, 10, 11 the results indicating that the solubility decreases with increase in nickel content, becoming zero for pure nickel. There is no published information on the solubility of these gases in either pure cobalt or alloys containing cobalt EXPERIMENTAL PROCEDURE Sieverts' method of solubility measurement was used throughout the investigation. The construction of the melting chamber is somewhat different from A. Optical pyrometer F. Alundum cover B. Vycor chamber G. Alumina crucible C. Furnace coils H. Alundum sand D. Glass water jacket I . Alundum thimble E. Chamber support J . Detachable vycor base sealed with de Khotinsky cement

Jan 1, 1961

By J. Farkas

A techno-economic assessment for the recovery of several elements from seawater is presented. Gold recovery has been used as an illustration for the economic evaluation of several processes. Current technology does not present any economically viable alternative to recover gold from seawater because its concentration is several magnitudes too low. However, with the increasingly larger availability of concentrated seawater, mainly from desalination and other processes, coupled with advances in technology, especially genetically modified specific microorganisms, may make the recovery of gold and other desired elements from seawater a reality in the near future.

Jan 1, 1984

By Oren C. Baptist, Carlon S. Land

Laboratory research has been conducted to evaluute the effect of clay hydration on the permeability to gas of water-sensitive reservoir sands. Samples of a .sandstone containing trace amounts of montmorillonite and a sample of montmorillonite were .studied in the laboratory to detertnine whether swelling or dispersion was the cause of permeability reduction in these samples. Heliuin, containing various amounts of water vapor, was used to hydrate the clay minerals and to determine the gas permeability at various stages of clay hydration. The amount of water adsorbed by the samples using this method is small. The nonwetting-phase permeability at higher water saturations war investigated by saturating the with water and measuring the permeability to humid helium while decreasing the water saturation, Relative-permeability curves obtained from results of these procedures were used to estimate the effect of the swelling of trace amounts of mont/tlorillonite on the permeability of the .samples. Most of the damage to the permeability when reservoir sands containing trace amounts of montmorillonite are exposed to fresh water is due to dispersion and movement of clays. Blockage of pores by the increased volume of expanded montmorillonite is believed to result in permeability damage that is small in comparison to the observed damage to the samples tested. INTRODUCTION Studies have shown that permeability is severely damaged when sands containing only small amounts of montmorillonite are contacted by fresh water.15 When samples of sands containing large amounts of montmorillonite are placed in fresh water in the laboratory, these samples may completely disintegrate, forming an unconsolidated mass of larger volume than that occupied by the dry sample." In this case, it is apparent that the swelling of montmoril-lonite has destroyed the pore structure of the sand. If only a trace of montmorillonite is present in a sand. samples may remain intact when saturated with water, although the permeability to water is a small fraction of the gas permeability of the dry sample. Many workers in the field of water sensitivity have attributed this reduction in permeability to the blocking of pores and reduction of pore size by the increased volume occupied by expanded mont- niorillonite. if the sand contains a detectable amount of montmorill'onite or mixed-layer clay containing rnontmorillonite. Logically3 the smaller amount of montmorillonite present in a sand, the smaller should he the effect of montnlorillonite swelling on permeability; however, the quantity of montmorillonite sufficient to cause severe damage by swelling is not known. Although hundreds of samples have been tested in our laboratory, no correlation has been established between the amount of montmorillonite in samples and the permeability reduction caused by fresh water. To many petroleum engineers, the phrase "clay swelling" is synonymous with "water sensitivity", or "permeability reduction" implying that any formation damage due to the hydration of clays is caused by swelling. Although all clays adsorb water on their surfaces, montmorillonite is the only clay mineral commonly found in reservoir rocks which adsorbs water between intercrystalline layers, resulting in expansion of the clay particle. As montmoril-lonite swells, the first few layers of water adsorbed between platelets are strongly held and well oriented, and the montmorillonite retains its crystalline structure, although expanded. As swelling of sodium montmorillonite continues, the platelets become farther apart and the forces orienting the platelets in the crystalline structure become weaker, resulting in a less orderly orientation of platelets. In an abundance of water, small groups of platelets may become detached from the original monl-rnorillonite particle and may be dispersed throughout the water phase. Because of its swelling properties, sodium montmorillonite is very easily dispersed in water. Particles of other clay minerals. such as illite and kaolinite may also be dispersed in water. causing water sensitivity of sands not containing montmorillonite. The presence of an immobile layer of water adsorbed on the surface of clays has been considered a possible cause of the low permeability to water of dirty sands. Grim states that the thickness of the layer of immobile water held by sodium montrnorillonite is three nlolecular layers or 7.5 A (angstroms), with some orientation of water extending to 100 A. Assuming a very thick, immobile water layer adsorbed on the surface of a pore represented by a capillary tube, the maximum effect of the water layer on permeability can be calculated. Using a pore radius of 10 ' cm and an immobile water layer of 50 A. the calculation shows the permeability to be reduced only 2 per cent. Similar calculations can be used to show that the effect of electro-osmotic counterflow is of the same order of magnitude as that of bound water. The reduction of the permeability to water by either an immobile water layer

Jan 1, 1966

By David B. Brooks

Identified potential resources of lead and zinc are lower, relative to reserves, than the same ratio for other metals, Either there is little material below present grades or, if it exists, there are no data on it. The author examines both these factors in detail, and also introduces a third possibility. In their 1961 monograph, The Future Supply of the Major Metals, Bruce Netschert and Hans Landsberg noted that identified potential resources (that is, known but submarginal resources) of lead and zinc were much lower relative to reserves (that is, known and supermarginal resources) than was the same ratio for other metals.' Put another way, it seemed that for such metals as iron, manganese, copper, and aluminum, slightly more favorable economic conditions or modest advances in technology would greatly increase reserves by permitting the exploitation of vast quantities of leaner or deeper or otherwise less valuable mineral deposits. But for lead and zinc, Netschert and Landsberg concluded that either: "(1) there is relatively little material below present cutoff grades; [or] (2) such material exists, but for some reason there are no data.'12 This situation, which they called "the lead-zinc anomaly'' has been subsequently discussed by other authors. The purpose of this paper is to carry the discussion further by examining the evidence in favor of (1) and (2) and by advancing a third alternative. There are at least two reasons for devoting time to the lead-zinc anomaly. First, while it is unlikely that we shall have to turn to alternative lead or zinc resources in the near or middle-term future, the longer run resource picture for the two metals is not so certain.3 Both within the United States and for the world as a whole, new discoveries will have to come at a fair pace to keep up with growing rates of consumption. Thus, it is important to see whether there exist lower grade or nonconventional potential sources of two such useful metals that we could turn to at some time in the future. The second reason for studying the lead-zinc anomaly is also related to resource adequacy, but is of more general significance. Depending upon whether the anomaly is technologic, geochemical, spatial, or temporal in origin, we shall be able to draw some conclusions about the resource picture for other metals. Can we expect the apparent pattern of lead-zinc resources to be repeated? If so, will technologic advances in either exploration methods or mineral processing be able to alter the pattern? Or is the pattern unalterably set by geochemical distribution? Most important, are metals characterized by what seems to be an anomaly, different in any way from metals for which low-grade or nonconventional sources already have come to be exploited, as the porphyry deposits have for copper. In sum, investigation of the lead-zinc anomaly represents a case study combining both physical and economic aspects that may open up a neglected area in evaluating mineral resource adequacy. WHAT IS THE LEALLZINC ANOMALY? There are two dimensions to evaluations of the potential of any mineral resource? The first involves the degree of certainty that we ascribe to the estimate: how much do we know about the size of the resource as a result of geological mapping, exploration, and mine development? This dimension is expressed by the terms measured, indicated, and inferred reserves (and, if you wish, 'undiscovered reserves'), all of which terms carry with them the implication of exploitability under current cost-price conditions. The other dimension to evaluations of a mineral resource involves the economic limits of the estimate: how will the size of the resource vary with different (usually more favorable) cost-price conditions? (This economic dimension should be understood broadly to include all factors bearing on the cost-price relationship. In this sense it subsumes technology because any resource is exploitable at some cost; the role of technology is to bring cost down.) The latter dimension is expressed in the terms potential or sub-marginal 'ore,' and is logically quite independent of the former. For example, we have relatively good measurements of the tonnage of manganese in low-grade deposits in this country, though they are too lean to be considered reserves; on the other hand, we are much less certain of our measurements of new lead and zinc deposits in Missouri, though there is no question but that there is a sizable reserve. Thus, it may be uncommon but is not a contradiction to talk of measured submarginal ore or inferred potential ore.

Jan 1, 1968

By J. B. Macelwane

Geophysics differs from geology and physics in in many respects. In the first place, geophysics is a complex science embracing the fields of seismology, geomagnetism, geoelectricity, geodesy, meteorology, vol-canology, physical oceanography, physical hydrology, tectonophysics and exploration geophysics. Geology is also a complex science and so extensive in its various fields that no one can master them all, and no part of geology deals in any sense with several of these fields of geophysics. In the second place, geophysics makes use of methods and instruments that are derived primarily from the science of physics. Geology, on the other hand, has methods of its own and it draws its borrowed techniques and its instrumental equipment not only from physics but also and perhaps primarily from chemistry and biology. The difference, therefore, between the geophysicist and the geologist lies partly in the phenomena that are observed, partly in the methods and instruments with which each carries on his exploration; but partly also, and perhaps principally, in the habitual attitude of mind and in the background of specialized training with which each approaches the problems presented by this planet of ours. The geologist as such, therefore, is no geophysicist. On the other hand, the physicist is not a geophysicist either. Isolation of each problem in a closed laboratow system under complete control is fundamental to the methods of the physicist. The geophysicist must apply physical instruments and physicomathematical reasoning to the study of physical quantities in their undisturbed natural environment. What, then, is a geophysicist? In the sense that he is a trained expert in all of the geophysical sciences, I do not believe that such a person ever existed. It would be beyond the possibilities of a single lifetime. I think there is confusion in our ideas and in our use of terms. We are not all thinking of the same thing when we say geophysics or geophysicist; yet we seem to talk as though we were. It is as absurd to say that the whole of geophysics belongs to geology because the field of a particular type of geophysicist—the exploration geophysicist —calls for some knowledge of geology as it would be to say that the whole of biology belongs to geology because a particular type of biologist—the paleontologist— needs some knowledge of geology. Development of a Geophysicist Since it is impossible to become an expert in all the fields of geophysics, and since students entering college seldom know the field they will choose as a career, what would we suggest as the best general preparation for work in geophysics, whether as a meteorologist, an oceanographer, a seismologist, a geodesist, a geomagneticist, a volcanologist, a tectonophysicist, a hydro1 ogist, or an exploration geophysicistp we may distinguish five phases in the development of a geophysicist: (I) his mathematical and scientific studies in high school; (2) the general mathematical and scientific

Jan 1, 1946

By D. E. Baldwin

A method has been devetoped for predicting the produced concentration profile for a miscible slug in a five-spot pattern. The technique consists of dividing the five-spot into radial etements and applying an approximate radial solution of the dispersion equation to each element. To test the method, laboratory experiments were conducted in five-spot models. The models were 2-ft X 2-ft X 2-in. Berea sandstone slabs simulating one quarter of a five-spot. An aqueous system was used with tritiated water as the tracer fluid. Effiuent concentration profiles were obtained for slug sizes ranging from 0.7 to 10.2 per cent of the pore volume. Agreement between predicted and experimental profiles was excellent. A prediction was also made for a field tracer test. For this case the predictive technique was modified to account for stratification by use of a layer cake model. INTRODUCTION Dispersion in porous media is of growing interest to the petroleum industry because of the increasing importance of secondary recovery operations. One of the controlling factors in the recovery of oil by miscible displacement or by the use of waterflood additives is the degree of mixing between the fluids of interest. Consequently, one of the prerequisites of any recovery prediction is an adequate method of predicting dispersion. Also, any quantitative interpretation of waterflood tracer tests is dependent upon the ability to determine the dispersion of the tracer as it flows through the reservoir. During the past few years there have been reported in the literature the results of a large number of investigations, both theoretical and experimental, concerning dispersion in porous media. (An excellent review of these results has been presented by Perkins and Johnston." Only a few of these investigations, however, deal with non-lin-ear flow systems. Raimondi et al.9 have presented an approximate solution of the dispersion equation for radial, diverging flow. Lau et al. 7 and Bentsen 1 have presented laboratory data for radial systems and have shown that the dispersion can be adequately predicted by Raimondi's solution. Bentsen has also presented a small amount of data for a radial, converging system. Brigham and Smith' have applied Raimondi's solution, with approximating assumptions, to a five-spot pattern to predict the behavior of a field tracer test. The afore-mentioned investigations have been concerned almost entirely with radial diverging flow and have neglected the effect of converging flow. For this reason the present investigation was undertaken to develop a method of predicting dispersion in a five-spot pattern including the effects of both diverging and converging flow. The method which was developed consisted of dividing the five-spot into diverging-converging radial elements and applying an approximate solution of the disperson equation to each element. DEVELOPMENT OF PREDICTION METHOD The development of the prediction method consisted of two phases: construction of a radial model of a five-spot pattern and derivation of equations to describe the dispersion in the radial model. FIVE-SPOT MODEL A radial model which simulated the flow characteristics of a five-spot pattern was constructed by dividing the five-spot into diverging-converging radial elements (Fig. 1). Because of symmetry the model represented only an octant of a complete five-spot. Each element had an included angle of l° (making a total of 45 elements) and a radius r, such that the sum of the individual element areas was equal to the area of the five-spot octant. The normal five-spot fractional flow behavior was determined by averaging the experimental five-spot data of Caudle and Witte,' Dyes, Caudle and Erickson 5 and Fay and Prats. 4 The resulting curve is shown as a solid line in Fig. 2. To match this curve with the radial model it was

Jan 1, 1967

By R. Hogg

INTRODUCTION The principal applications of the flocculation process in the coal industry lie in the area of waste water treatment. Consequently, the concern is more with the behavior of the associated minerals, clays for example, than with the coal itself. At the same time, however, the presence of even small amounts of fine coal can significantly influence the performance of the flocculation operation. Coal preparation waste water treatment is a substantial problem involving over 200 billion gallons of water annually. There can be no doubt that these quantities will continue to increase as coal production increases and environmental considerations dictate the increased use of closed circuit systems and tighter control of effluent quality. Furthermore, we can expect to find a continued increase in the amount of fines generated in the coal mining and processing operations. Modern mining techniques tend to yield a finer raw coal with a higher ash content. The greater emphasis on fine coal cleaning for improved sulfur and ash removal and increased coal recovery will also lead to greater demands being placed upon the wastewater treatment system. The costs of "blackwater" treatment have been shown to vary widely from plant to plant (1). Part of this variation can be attributed to differences in the coal being mined and the plant flowsheet but there are no doubt significant contributions from the improper design and operation of treatment facilities.

Jan 1, 1980

By E. S. Wheeler

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

Jan 1, 1944