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By P. LEROY FOSTER

G EOPHYSICAL prospecting was presented in its several aspects and discussed with much vigor at two sessions during this year's annual meeting of the Institute. The first session was devoted entirely to the presentation and discussion of various technical papers, while the second meeting took the form of a round table conference on the advisability of revising the existing mining laws to recognize the results of geophysical prospecting. This conference was immediately followed by further consideration of technical papers. Each session was well attended and great interest was displayed by everyone present.

Jan 1, 1929

By FORTUNATO PEREIRA

(San Francisco Meeting, October, 1911.) I. GENERAL DESCRIPTION. The Department of Narino (formerly included in the Department of Cauca) is a narrow band about 170 km. (100 miles) wide in the southern part of the Republic of Colombia, FIG. 1.-SKETCH-MAP OF THE SOUTHWESTERN PART OF COLOMBIA. near the boundary of Ecuador, as shown in the sketch-map, Fig. 1. Its capital is Pasto, a small city of 25,000 inhabitants; the principal towns are Túquerres, Cumbal, Ypiales, Barbacoas, and Tumaco. The port on the Pacific ocean is Tumaco, and traffic in the interior is carried partly on the Patia river (steam navigation to the fluvial port of Barbacoas), and afterwards overland over poor roads by human bearers or on mule-back.

Aug 1, 1912

By Grimes, J. A.

EXTENSIVE discovery 'and rapid exploitation of orebodies within the past half century have attracted many able geologists to the mining industry and furnished them a wealth of data from which to develop theories concerning ore genesis. By tosting and elimillating theories which are not sufficiently sup- ported by fact, or which are based on inaccurate observation of field data, the trend of geological opinion has . moved strongly in certain directions until, at the present time, large numbers of geologists subscribe to a broad concept of .ore genesis that I would summarize as below:

Jan 1, 1928

By Robert L. Dean

THE pioneer mining company in Idaho to use airplanes extensively is the Yellow Pine project at Stibnite now owned by the Bradley interests. From 1901 to 1903 the gold boom at Thunder Mountain, in central Idaho overflowed to adjacent areas, prospectors discovering cinnabar and stibnite near the present site of Stibnite in Valley County. The workings were practically abandoned by 1911 through lack of capital and high costs of transportation on pack train roads over several mountain passes open only five months each year. During the World War there was some prospecting and production, and in 1921 twelve of the original companies were merged. Small-scale mining up to 1927 proved that an expenditure of several million dollars would be necessary to operate profitably. These properties were purchased by the Bradley interests during the period of 1927 to 1930. In 1927, there was no mining equipment except hand tools, no telephones, and only one building. Two mountain

Jan 1, 1935

By RAYMOND M. LARSEN

The area covered by this paper is the same as that covered in 1944. Colorado, Montana, Utah, and Wyoming are included in the discussion and statistics, and brief mention is made of activities in the adjoining states, except Nebraska and New Mexico, which are considered separately (see pp. 187-189). The other adjoining states, North and South Dakota, Arizona, Nevada, and Idaho, have had virtually no oil or gas production, except in the gas field of Cedar Creek. Montana, which extends into North Dakota; the Pierre field in South Dakota, where gas is produced and separated in gas-water wells, and the abandoned Payette area in western Idaho. Seven gas wells were drilled in North Dakota, but no wildcatting was reported. Several unsuccessful wildcats were drilled in South Dakota, and some were continuing at the end of the year. Activity in Idaho and Nevada was negligible.

Jan 1, 1946

By Frances H. Clark

IN a concern with the varied interests of the Western Union Telegraph Co., where practically all types of metals, both ferrous and nonferrous, are utilized, many types of failures of materials occur. These have to do not only with outside plant construction, such as corrosion and fatigue of line wire and cable, but also with inside plant equipment operating at such high speeds that rapid deterioration of metal. parts due to fatigue and wear results. Both corrosion and fatigue affect the life of copper wire so its normal life in any particular locality is largely dependent on the atmospheric conditions. Tensions vary widely owing to changes in temperature and ice and wind loadings and the wire is Subject to a great range of vibration caused by wind gusts aril vibration front trains or other heavy vehicles transmitted through the earth. High frequency low-amplitude vibrations are sometimes audible as singing in the wire. The other extreme is the vertical slashing or dancing of the wire observed during severe storms where amplitudes of 9, ft. or more at low frequencies have been observed.

Jan 1, 1942

By J. Fred Johnson

MORE ORE is mined in the Bingham District than in any other mining district in Utah. In addition to the open-pit operations of the Utah Copper Co., there have been, many large underground mines. Until recent years the principal production was from the Jordan and Commercial limestones, but in the last eight years valuable ore deposits have been developed in the so-called alphabetical or "A," "B," "C," and "D" limestones, mainly by the U. S. Smelting, Refining & Mining Co. The value of these developments has led the company just mentioned to acquire large holdings in the district and within the last year to install at the Niagara shaft a hoist capable of going to a vertical depth of 4000 ft., or 1800 ft. deeper than the present lowest level. Ore from Bingham has been the chief factor in enabling the

Jan 1, 1934

By AIME AIME

General Local Committee.-John Fritz, Chairman; A. B. de Saulles, Vice-Chairman.; R. M. Bird, Treasurer; Henry S. Drinker, Secretary; Robert H. Sayre, E. P. Wilbur, Charles M. Dodson, Abraham S. Schropp, E. M. McIlvain Archibald Johnston, A. B. Fichter, C. G. Convers, W. A. Wilbur, Garrett B. Linderman, Frederick Conlin, George Pettiuos, Albert Brodhead, Garrett L. Hoppes, M.B. Cutter, H. J. Seaman, C. A. Matcham, B. F. Fackenthal, Jr., A. L. J. Queneau, Geo. R. Elder, Eldridge Wilbur, William H. Chandler, Mansfield Merriman, Joseph F. Klein, William S. Franklin, William Esty, Joseph AN'. Richards, Howard Eckfeldt, John D. Irving. Transportation Committee.-H. J. Seaman, C. A. Matcham, B. F. Fackenthal, Jr., A. B. Fichter, A. L. J. Queneau, Henry S. Drinker. Hotel Committee. -Garrett B. Linderman, Charles M. Dodson, W. A. Wilbur, Garrett L. Hoppes, Albert Brodhead. Steering Committee.-William S. Franklin, William Esty, John D. Irving, R. M. Bird, the members of the Tau Beta Pi Society of Lehigh University. Committee on Meetings - William S. Drinker, Joseph W. Richards, Howard Eckfeldt. Entertainmment Committee.-W. A. Wilbur, E. M. McIlvain, Archibald Johnston, A. B. de Saulles, G. G. Convers,.A. L. J. Queneau, Garrett B. Linderman, Frederick Conlin, George Pettinos, Garrett L. Hoppes, Henry S. Drinker, William S. Franklin, Eldridge Wilbur, Robert M. Bird, Secretary. The opening session was held at 8.30 p.m., Wednesday, February 21, 1906, in Gymnasium Hall of Lehigh University, which had been tastefully decorated with flags and bunting. Dr. Henry S. Drinker, President of Lehigh University, and Secretary of the General Local Committee, called the meeting to order, and welcomed the Institute to the Bethlehems, where its first meeting, after its organization in May, 1871, at Wilkes-Barre, was held in August, 1871.*

May 1, 1906

By AIME AIME

THIS journal is fully indexed-every issue, as soon as published-in a set of card?, which thus brings ready to your hand any article on any subject in this journal or in any one of 1700 other journals in all languages. This Engineering Index Service, instituted in January, 1928, is to be found in the Public Libraries of Newark, Cleveland, Bridgeport, Baltimore and the John Crerar Library, Chicago. Engineers in any field who live or work in New Jersey will find this mammoth index to the latest engineering literature in the Public Library of Newark, N. J.

Jan 1, 1929

By Stanley W. Ivosevic

The South-Central Osa Peninsula produced around 30,000 kg (100,000 troy oz) of gold since prehistoric times. Gold freed by erosion from quartz lodes in the Mesozoic Nicoya ophiolite complex was reconcentrated through three generations of Quaternary sedimentary deposits. Resultant gold placers grade upward from 1 g/m3 (0.03 troy oz/m3) and are of moderate size.

Jan 1, 1980

By H. C. George

CAREFUL- sampling and good judgment as to probable recoveries are important factors in estimates of ore reserves, based on prospecting drilling results, but other factors are equally as important and may be more misleading and perhaps disastrous if not properly interpreted. Some of these are: 1. The case where no, ore is shown in the "sludgings," when, as a matter of fact, the drill has passed through a thick sheet of ore which has been broken up and washed away into open crevices. In numerous cases, later mining operations have shown that this has happened. This condition may be discovered by shooting the drill .hole at the point where the open crevices occur, but shooting should not be done until after the drill hole is completed, because the resulting shattered formation may salt the drill hole at lower levels. 2. The case where rich cuttings are shown for a thickness of 20 or 30 ft., when ore was encountered in only the first sludging. Owing to soft or loose formation, the ore from the first sludging has salted the lower sludgings. The presence of large pieces of ore and a similar ratio between zinc and iron assays in the lower sludgings frequently indicate this condition. In the lower sludgings, the presence of oxidized ore in unaltered limestone sometimes shows this condition. 3. The case where the drill hole shows a considerable thickness of ore; but owing to the presence of a vertical sheet of ore, perhaps not more than 1 in. thick, at the place where the drill hole is located, the good assays resulting might be misleading. If this condition is suspected, the drilling of several more holes within a distance of 10 or 15, ft. will usually show it.

Jan 1, 1921

By F. H. Wilson, E. W. Palmer

Brass mills are familiar with a recurring problem which reveals itself during deformation of annealed metal as an opening up of cracks which are suggestive of a grain boundary pattern. A typical example is seen in Fig 1, which shows part of the convex surface of a cartridge brass disc which was slightly dished by the punching operation. Another illustration of the same type of defect was found in the surface of a finished cartridge case which split open on firing. These cracks, shown in Fig 2, were away from the split but indicate the presence of the type of weakness which permitted the splitting. Usually the weakness consists of separate cracks, the lengths of which are of the same order of magnitude as the grain size prior to the final anneal. Their typical appearance in a polished section is shown in Fig 3. This structure was found below the surface of a fractured tensile-specimen that had been cut from a large cartridge blank showing the defects on its convex surface. While the pattern formed by these cracks suggests a grain boundary origin, the cracks bear no relation to the currently existing grain structure. Thus Fig 3 shows that the grains have grown up to cracks already present. Since it is doubtful that the cracks were present in the metal before the anneal, they must have formed during the anneal but prior to recrystallization. The term "fire-cracking" has been generally applied to cracking that occurs during an anneal under the influence of internal stress, but refers more specifically to obvious macroscopic cracking attributable to the presence of a low melting phase, usually lead. Since the type of cracking described above may occur when the lead content is very low, we have considered it a somewhat different phenomenon, and have called it "inter-granular parting." While most examples involve cartridge brass, intergranular parting has also been observed in the fabrication of large seamless tubes from discs of both 85/15 red brass and 70/30 cupro-nickel. Similar cracking in nickel silver was investigated by Jones and Whitehead,1 who showed that it could occur during healing or cooling. That which occurred on heating they called "fire cracking," and they suggested that, a transformation at about 320°C might account for its occurrence. It was felt in this laboratory that the observed parting was probably one aspect of the general observation, first made by Rosenhain and Archbutt,2 that a tendency toward intergranular fracture under tensile stress increases with increasing temperature and decreasing rate of strain. In this case the stress involved would be internal. The rate of strain would be exceedingly slow, a localized internal creep. Reference to the literature uncovered no efforts to extend the observations of Rosenhain to conditions involving only internal stress. Accordingly, an exploratory research, sufficient in detail to satisfy us as to the probable truth of this explanation of the observed intergranular parting, was undertaken. The internal stresses present during the early stages of an anneal (prior to recrystallization) would be from two sources: residual stresses developed during deformation, and thermal stresses caused by uneven heating and expansion. Thermal stresses would vary widely according to shape, size and manner of heating, and can be considered as supplementary to residual stresses. It seemed necessary to determine the stress and temperature conditions under which parting would occur in a relatively short time, and then to establish whether or not in- ternal stresses may persist to an extent adequate to cause parting at such temperatures. (Jones and Whitehead1 and Moore and Beckinsale3 made tests which indicated that stress relief required an appreciable time.) During the course of the research the desirability of studying the effect of grain size became apparent, and this factor is one of the major variables of our investigation. Intergranular Parting under Tension at Elevated Temperatures In early experiments, hard 70/30 brass tensile specimens, with unknown residual stresses, held for 10 min. at applied stresses from 30,000 to 40,000 psi at temperatures from 300 to 350°C, showed no macroscopically visible cracks when unloaded and cooled, but cracks very similar in appearance to those observed in commercial practice were revealed in these specimens by pulling them to fracture. Annealed specimens, on the other hand, showed no cracks in such experiments, apparently because they deformed plastically at stresses below those necessary to cause parting in a reasonable time. Hence, the specimens used for this study were first strengthened by cold tensile elongation, giving them an unavoidable residual stress pattern (determined largely by grain size and orientation) which would, however, correspond in direction, at least, to the stress pattern obtained under stress at temperature. A variation in these residual stresses might be expected with variations in grain size, but following any given anneal the reproducibility of stress pattern should be as good as that of the grain size measurement. With no information as to the effect of the amount of prior deformation, tests were conducted on specimens given the same cold elongation, using a stress applied at temperature which was a constant proportion of the stress required to produce this elongation. In

Jan 1, 1950

By J. F. Myers, F. M. Lewis

DISCUSSION L. E. Djingheuzian (Canadian Dept. of Mines and Technical Surveys, Ottawa)—In their Summary the authors say: "Reconciling the grinding efficiency with good metallurgy is still a problem." In the discussion of the first paper8 in his reply to W. I. Garms, Mr. Myers states: "Our grinding process with smooth I-in. balls has reduced by nearly one half the metallic losses in the fine micron sizes of the tailing. This is simply because less of the fine micron sizes are produced. Since the + 65 mesh size is the same as formerly, a higher percentage of the intermediate sizes are developed. These sizes have the highest floatability, require the least reagents, and use less floating time. "These factors contribute so heavily to the overall economies that dropping our power grinding gain from 28 pct back to 19 pct is a small detail. However, we feel that this is only a momentary situation and that eventually the best features of the grinding and flotation processes can be brought together, which is as it should be." Italics are mine. The above statements, to me, appear to be the answer to the opening statement in the Summary. Denoting the costs at different power grinding gains as: Power Grinding Power Grinding Gain, 28 Pct Gala, 19 Pct Cost of grinding G G1 Cost of flotation F F1 Value of metallic losses T T1 where G1 > G2 F3 < F, and T1 < T, we have: G1+Fl+T1<G +F+T. Since the authors accept the idea that "grinding in flotation plants becomes part of the &apos;conditioning&apos; of the feed to flotation",4 i.e., that in flotation the ball mill is primarily a conditioning machine, it can be postulated that Tennessee Copper grinding at cost G1 is more efficient than grinding at lower cost G. This can be directly inferred from the Conclusion of the paper. Mr. Myers also emphasizes this at the end of his reply to Mr. Garms: "that grinding is for the purpose of preparing flotation feed and not grinding per se." This, to me, in the final analysis means that when the efficiency of grinding is weighted against the conditioning factor, the former becomes a function of efficient conditioning, hence, within the system in which proper conditioning is the dominant factor, the best grinding efficiency is provided by grinding which will contribute towards the optimum conditioning. This brings us again to the statement: "that if every grinding unit were considered as a conditioner for each following step, efficient grinding plants would become much easier to design."&apos; In other words, grinding equipment should be balanced against the flotation equipment and against chemical reactions taking place in the system. F. C. Bond (Allis-Chalmers Mfg. Co., Milwaukee)— The authors&apos; discussion of the probable ball motion in a slow speed high dilution mill is very interesting. When the 1-in. balls have worn down to about one fourth of their original weight they apparently first develop a flat surface; as wear progresses this flat face becomes concave, and other concave faces appear. It seems more probable that the first flat face may form at the softest part of the ball surface, and that each succeeding contact tends to force this flat face into sliding contact with a larger round ball; than that the flat faced ball tends to pair off with a particular round ball and to travel with it continuously. When the small worn ball has a flat face and is in sliding contact with a large round ball, the surrounding large balls will assume a more or less definite pattern, and slide against the worn ball, thus producing secondary concave faces. The primary concave face seems to be larger and better developed than the secondary faces. The ball charge can be divided into "concaves" which show at least one concave surface, "intermediates" which have developed flats or incipient concaves, and "rounds." Ball slippage is always present in a tumbling mill, and the mutual ball movement is necessarily a combination of rolling and sliding. The sliding motion is apparently concentrated upon the smaller worn balls which nest between the surrounding larger round balls. When each worn ball starts its upward path in the mill its primary flat or concave surface fits against a larger round ball, and the round ball slides upon it. The action may be something like that of the ball separator in a ball bearing, except that the worn sliding balls are always under considerable pressure. The material is ground under the combined influence of breakage 1—by impacts between falling balls and between falling and supported balls, 2—by being nipped between rolling balls, and 3—by being rubbed between the sliding balls. The rubbing action will be increased in the presence of worn balls with concave surfaces. The rubbing action probably produces a considerable portion of the finely ground slimes in the product. The worn balls commonly approach tetrahedrons in shape, and are very different from concavex, each of which has two equal opposed concave surfaces. Concavex were designed only to grind upon themselves, and not for use in combination with grinding balls. Their action in a grinding charge is very different from

Jan 1, 1952

By Jean Howard

ThE formation of the (100) [001) texture in 3-1/4 pct Si-Fe strip was first reported by Assmus ef a1.l in 1957. Since then much experimental work has been carried out with a view to establishing the mechanism involved. The papers cited above state that the (100) [001] texture was developed in strip rolled from material melted and cast in vacuum. (The impurity content of the ingot is reported as 0.005 pct.) The present note records that similar results can be obtained in material processed by powder metallurgy. A processing schedule is described.which enables the texture to be formed in strip up to 0.010 in. thick, but there seems no reason why this should not be achieved in thicker strip, provided that large grains are developed after sintering. The materials were prepared from Carbonyl Iron Powder Grade MCP (particle size 5 to 30 p) of the International Nickel Co. (Mond) Ltd. The powder contains about 0.15 pct 0, 0.01 pct C, 0.004 pct N, <0.002 pct S, $0.005 pct Mg and Si, and 0.4 pct Ni— that is, it is substantially free from metallic impurities other than nickel, which is thought to be unimportant in the present work. The silicon powder was 99.9 pct purity, or material of transistor quality (ground in pestle and mortar). The mixed powders (3-1/4 pct Si to 96-3/4 pct Fe) are heated in hydrogen at 350" and 650°C to deoxidize the iron before sintering loose at temperatures between 1350" and 1460°C (depending upon the ultimate thickness of strip required) for up to 24 hr. The object of the high-temperature sinter is to develop a large grain size at this stage. Alternatively, the loose sintering can be done at a lower temperature followed by rolling or pressing and then annealing at temperatures between 1350" and 1460°C. Both methods produce large grains, which remain large throughout the process. The compact is then hot-rolled to approximately 1/8 in. with high-temperature interstage anneals if necessary. This step is taken to avoid intercrystalline cracking which would occur if the material of such large grain size were cold-worked. The bar is then annealed at 1050°C and reduced to its final thickness by approximately 50-pct reductions and 1050°C interstage anneals. Throughout the process the dew point of the hydrogen furnace atmosphere is maintained at about -40°C. Samples were annealed in hydrogen at various temperatures and times. Secondary recrystalliza-tion to (100) [001] was developed on the thinner material (i.e., up to 0.002 in.) by annealing in hydrogen at 1050" to 1200°C with a dew point of - 40°C or in vacuum (10-5 Torr) at 1050°C. With the thicker materials (i.e., up to 0.010 in.) the best results were obtained by annealing in hydrogen at 1200°C with a dew point of - 55°C. Complete secondary recrystal-lization to (100) [001] textures was obtained. Above these temperatures secondary recrystallization to (110) [001] tended to develop. The final annealing of samples was normally carried out with the samples placed between recrystal-lized alumina plates, but some experiments were performed with the samples suspended so that their surfaces were not in contact with anything except hydrogen, and these were equally successful in developing secondary crystals. An approximate determination of the proportion of material (before secondary recrystallization took place) having crystals with the (100) or (110) planes in or near the rolling plane showed that 11 pct of the sample had (100) and 16 pct (110). The method used for the determination is described below. A sample was annealed at a temperature just below the secondary recrystallization temperature and etched to reveal the (100) planes. The approximate area covered by crystals having (100) or (110) in or very near the surface was measured on the screen of a Vickers projection microscope. This was repeated for twenty positions chosen at random and a mean of the results calculated. The main hindrance to developing the secondary crystals in the thicker materials was the difficulty of obtaining a large enough initial primary grain size before secondary recrystallization. This was overcome by increasing the particle size of the silicon powder used. During the course of the work, it had been observed that the larger the grain size after sintering the more likely it was that the material would be successful in developing secondary crystals at a later stage. An experiment was therefore carried out to determine whether the material with the larger grain was more successful in developing secondary crystals due to the large grain produced at the sintering state per se or whether it was due to the greater reduction of silica brought about when the sintering temperature was raised in order to increase the grain size. A comparison was made between two compacts, one of which was made with silicon powder of 60 to 100 mesh, the other with silicon powder which was finer than 200 mesh. F?r this experiment, use was made of a phenomenon previously observed that the larger the particle size of the silicon powder employed in making a compact, the larger is the grain size of the compact. The silicon powder was ground

Jan 1, 1964

By H. J. Tschirner, L. P. Davidson, R. K. Carpenter

HE electrolytic zinc plant of the American Zinc Co. of Illinois, at Monsanto, was expanded in 1943 to a capacity of 100 tons of slab zinc daily. This capacity was not attained because of inability of the leaching plant to deliver an adequate amount of solution for electrolysis. Changing the leaching method so that the acid was added to the roasted zinc material reversed the usual procedure and made it possible to attain the desired capacity. The conditions which prevented satisfactory work before this change and the difficulties which arose in reversing the usual leaching procedure are described. The "reverse" leach operation as now practiced is carried out as follows: All the calcine to be leached is fed continuously to a slurry mixing tank. About one third of the acid to be used is fed to the tank with the calcine. The slurry is discharged continuously to a Dorr duplex classifier in closed circuit with a Hardinge mill. The classifier overflow is pumped to any of six leaching tanks where the leach is completed. A finished leach is discharged through Allen-Sherman-Hoff pumps to Dorr thickeners, from which the overflow goes to the zinc dust purification and the underflow to vacuum filters. This change in leaching procedure from the usual one of adding calcine to a large amount of acid made it possible to provide an adequate amount of purified solution to the electrolyzing division and at the same time filter and dry all the residue produced. Operating savings in reagents and better metallurgical recoveries were also important benefits. The original flowsheet of the leaching plant provided leaching, sedimentation of the insoluble residue, and purification of the neutral zinc sulphate solution with zinc dust. The thickened residue was filtered and washed. The purification cake of excess zinc dust, precipitated copper and cadmium, and any insoluble residue was filtered off on plate-and-frame duplex classifier. Settlement in the thickeners was inadequate and the suspended solids in the thickener overflow gave rise to filtration difficulties after the zinc dust purification. Further, the filtration and washing of the leach residue was poor, and it became necessary to pump a large amount of unwashed or poorly washed residue to storage ponds outside the plant building. Two causes of the poor settling and filtration were determined: Soluble silica and ferrous iron in the calcine treated. The latter was a result of poor roasting and with more experience ceased to be a major problem. The silica was a normal constituent of the feed and the working out of the problem became a matter of controlling its solubility. The obvious method to render the silica insoluble was by intensive roasting. This, however, met with total failure as such roasting resulted in silicates, probably zinc, soluble in the 13 pct acid used for leaching. Attempts were made to coagulate the fine gelatinous slime with addition agents. Glue, lime, starch, beef-blood serum and others were tried without success. All the suggested tried-and-tested means of operating the thickeners gave no consistently good results. Variations in leaching time, in addition of calcine to the leaching tanks, "conditioning" of the pulp by prolonged agitation, immediate discharge of the leach upon completion to avoid breaking up flocs were all tried and given up as ineffective. Byron Marquis, of Singmaster and Breyer, worked with the plant staff on a beaker scale until a leaching procedure was developed which gave consistent results and a promise of overcoming the difficulties which had plagued the plant operation. It was suggested that the difference in solubility of silicates and zinc oxide in sulphuric acid could be made use of in a leaching method where the acidity was controlled carefully. Such control is possible when acid is added to a slurry of calcine. This process reverses the normal procedure of adding calcine to a vessel of acid, hence the term "reverse leach" was applied. In this way, the overall acid concentration can be kept very low. In the tests made, it did not exceed 0.05 g per liter free sulphuric acid. Numerous advantages were realized when no silicates were taken into solution and later precipitated as a bulky gel. The gel had made reasonable thickening and filtration of the leach pulp and practical drying of the residue impossible. When the gel was eliminated, thickening rates were increased as much as five times. The volume of residue after thickening represented about 10 pct of the total leach pulp and had been as high as 95 pct when the gel was present. The thickened pulp was filterable and the filtered cake was dried readily after washing. The zinc extraction from the calcine was slightly lower. This was more than compensated for by the increase in zinc recovered in solution from zinc which had been trapped in the gelatinous residue. The amount of copper recovered was lower. However, the amounts of other impurities, such as arsenic, antimony, and germanium, taken into solution were lower. This was particularly true of antimony. Since the inception of reverse leaching, no concentrates have failed to yield solutions free of antimony even when present in the calcine to the extent of 0.2 to 0.3 pct. Oxidation of ferrous iron is a problem of reverse leaching. Ferrous hydrate does not precipitate at pH 5.3 to 5.4 where a leach is finished. The usual oxida-

Jan 1, 1952

By J. D. Price, W. M. Bertholf

A. C. RICHARDSON*—First of all, [ think that the paper represents a lot more work, study, and correlation than has been indicated by the brief talk by Mr. Price. I like the way he started out and described the areas from which the samples were obtained, the locations of the washing plants, the available tonnages, and other background information with which to evaluate the data he submitted later on. Then I like the way in which he described the various types of washing plants, the tonnages handled and the difficulties of the washing problems; showing the amount of material that lies close to the specific gravity at which the washing separation is made. Later he gave figures from washing plant operations showing recoveries and cleaning efficiencies. He then discussed his own plant at Pueblo. It is the same old plant, I think, that I worked around a good many years ago. It is unusual to find a plant treating nearly 5000 tons of coal a day on tables. But this table plant is, I believe, more efficient than is indicated by the figures that Mr. Price gave. To determine the efficiency of a cleaning operation or to compare it with another it is necessary to consider the quantity and character of the material close to the specific gravity at which the separation is made. It is not fair, I believe, to penalize the table operation by something like 4 pct of out-of-place-material as he has done here. The variety and difficulty of the coals that he has to wash, the continuous shift and change in their composition make a very difficult cleaning problem and the table performance is excellent. I believe that the information in this paper will be of interest and value to anyone operating or planning to build a coal cleaning plant in this or other areas; particularly where the cleaning of fine coal is a problem. The data may be used for comparative purposes in determining the relative efficiencies of other cleaning plant separations. E. D. HAIGLER*—What is a Baum jig? J. D. PRICE (authors&apos; reply)—A Baum-type jig is one in which the pulsations of the water is secured by means of a pulsating air current applied on top of the water. I imagine you are all familiar with the old plunger-type jig which is in effect a U tube in which a plunger on one side of the U, moving up and down, causes a corresponding pulsation on the far side of the jig. In the Baum jig, the pulsating air current is applied on the surface of the water on one side of the U tube of the jig and gives a corresponding pulsation on the other. It is also commonly known as a pneumatic jig. The control of the rise and fall of the water in the jig body proper is under much better control than it is in any of the other type jigs. Mr. Richardson could enlarge on that feature, for I know that he has had considerable experience with these jigs. A. C. RICHARDSON—You have asked how to control a Baum-type jig. The pulsations in a Baum jig can be modified and regulated to a marked degree by the amount of water admitted to the jig and by the adjustments of the valve which regulates the manner in which air is admitted. The number of pulsations per minute is controlled by the number of cycles of the air valve. Thirty to forty cycles per minute is a good speed for large jigs treating coarse sizes of cod. With an air valve it is possible to modify the time-velocity curve of the pulsating water to some extent which in turn determines the action in a jig bed. Within limits the following parts of the air valve cycle may be regulated: (1) the rate and period of air admission, (2) the period of air expansion, (3) the rate and period of air exhaust, and (4) the period of air compression. The rate and period of air admission determines the acceleration of the water at the beginning of the pulsion stroke and the amplitude of the stroke. The period of air expansion, after inlet port is closed, is one in which the water has reached the desired velocity, positive acceleration reduced, and the bed held in a mobile condition. The rate and period of the air exhaust can be adjusted to modify the degree of suction and so modify the manner in which the particles in the bed stratify. The compression period, alter the exhaust port closes and before the intake port opens may be used to advantage in retarding the downward velocity of water during the suction stroke. An ideal jig stroke is one in which during the up stroke the bed is lifted slowly in a mass and opens up like an accordian with the bottom layers dropping away first. With the bed open and mobile the particles adjust themselves according to their hindered settling rates. During the down stroke, while the bed is still open the particles of high specific gravity are accelerated toward the bottom layers. It is possible to approach this stroke with all types of jigs but it is less difficult to approximate it with a Baum jig.

Jan 1, 1950

By George F. Learning

TOTAL DIRECT IMPACT The uranium mining industry&apos;s principal economic impacts on the Texas economy are the result of three flows of money from the industry into the remainder of the state&apos;s economy. These three are: (1) money paid to individuals (personal income) ; (2) money paid to other businesses (business income); and (3) money paid to state and local governments (government revenues). As these direct payments from the uranium industry to various other sectors of the Texas economy subsequently circulate and recirculate within the state, the indirect effects of uranium mining&apos;s direct impacts multiply to reach amounts significantly higher than the direct income flows alone. Over the past decade, the uranium mining industry has substantially increased its role as a provider of jobs, personal income, business income, and government revenues in Texas. The growth has come almost exclusively in a largely rural, seven-county area that lies within the triangle formed by the Laredo, San Antonio, and Corpus Christi metropolitan areas. The uranium mining industry, in fact, has been the major dynamic element in this rural area despite relative stagnation in most of the region&apos;s other basic economic sectors. Over the three years from 1976 to 1978, the South Texas uranium mining industry directly contributed a total of $115 million to the economy of the seven- county region in which it operated and $164 million to the economy of the entire state of Texas. In 1979 alone, the total direct contribution of the industry to the Texas economy had climbed to $124 million in personal, business, and government income. PERSONAL INCOME IMPACT In the period from 1976 through 1978, the South Texas uranium mining industry provided an average of $12.5 million in personal income each year directly to residents of Atascosa, Bee, Duval , Karnes, Live Oak, McMullen, and Webb counties -- the seven Texas&apos; counties that make up the South Texas Uranium Belt. A1 though 84 percent of this resulted from the employment of area residents in uranium industry jobs, some amounts were also provided by the payment of rents and royalties to land owners for the use of their land and mineral rights in uranium mining operations. In 1979, the uranium industry provided approximately $38 million to residents of the Uranium Belt and the rest of Texas. This was more than double the average of $16.1 million provided to Texas residents during the 1976 to 1978 period. The full importance of the uranium industry as a source of personal income, however, should not be reckoned merely by the amount of wages and salaries that it pays directly to its own employees, nor by its rent and royalty payments paid directly to land and mineral rights owners living in Texas. The added payments that the industry makes directly to other Texas businesses and state and local governments in Texas are themselves converted into personal income as those business firms and government units in turn pay their employees. All of the direct income payments made by the uranium industry circulate and recirculate within the state&apos;s economy, multiplying their impact as they go, until they eventually all leak out of the state as federal taxes or as payments to individuals or businesses located outside of Texas. The combined circulation and recirculation of the direct personal, business, and government income that was provided by the-uranium industry in Texas during 1976, 1977, and 1978 resulted in an average annual amount of indirect personal income of more than $83 mill ion. This alone was $20 mill ion more than the industry&apos;s average annual sales during the same years. The total of combined direct and indirect personal income contributed to the Texas economy by the uranium mining industry in that same three-year period thus averaged almost $100 million annually. In 1979, the amount of indirect personal income contributed to the Texas economy by the circulation of uranium mining&apos;s direct contributions had risen to about $196 million, more than double the average of the previous three years. The combined direct and in- direct personal income impact in 1979 thus amounted to $234 million. BUSINESS INCOME IMPACT The income provided directly to other Texas business firms through the purchase of needed goods and services by the uranium industry has been twice as big as the industry&apos;s payrolls. In 1976, 1977, and 1978, the South Texas uranium industry spent an average of almost $36 million each year to buy both goods and services from other Texas businesses. By 1979, this direct contribution to the Texas economy had swollen to $76 million. The biggest share of the uranium industry&apos;s payments to other businesses have gone to contracting firms, including both construction firms and those providing specialized mining services. In the past four years, about 40 percent of the direct payments made by Texas uranium producers to other Texas firms have been to contractors. Texas wholesale and retail firms have also shared in the business sales provided by the South Texas uranium mining industry. Over the past four years, Texas wholesale and retail trade businesses have accounted for about 34 percent of the uranium mining industry&apos;s purchases from other Texas businesses. Public utilities firms have received another six per- cent, while Texas manufacturers and transportation firms have accounted for about five percent each. The other sectors of the state&apos;s economy, including other mineral industries, agriculture, finance, insurance, real estate, and services, have accounted

Jan 1, 1980

By A. A. Collins

H. R. BIANCO*—I should like to ask Mr. Collins if that statement he made about the addition of drosses to the blast furnace slowing down the blast furnace is a result of his own experience or a result of the experience of some older metallurgists; and perhaps I should ask him to define the type of drosses that he means. A. A. COLLINS (author&apos;s reply)— That has been my own personal experience with dross. On various occasions at Chihuahua we attempted to incorporate the dross in our regular blast furnace charge and to shut down the dross re-verberatory to try to save some money. As expected, we had very poor results. I think that Ed Fleming will well remember on one occasion, that was back about 1933, when we attempted the first experiment along this line, and as a result of the sulphur addition to the blast furnace to matte out the copper we ended up with hanging furnaces and mushy slags and abandoned the dross experiment, once again turning to the use of the reverbera-tory for handling dross. H. R. BIANCO—Is that dross you refer to from the drossing kettle ? A. A. COLLINS—Yes, the dross that I am referring to came from drossing kettles. Furthermore, to back up my previous assertion, I had occasion in 1943, while up at Leadville, to once again experience the routing of dross through the blast furnace with its sulphur addition, since they had no dross re-verberatory, and to observe that once thf dross was removed, the furnace was speeded up almost 100 tons a day. All of these are personal experiences and I think that Mr. Feddersen also has had a little experience along this line —in fact, I believe all of us have had some experience. H. R. BIANCO—I know at Trail they recirculate considerable dross through the blast furnaces and we also recirculate dross at Herculaneuin and I am not aware that it has done much towards slowing down the blast furnace. A. A. COLLINS—We have always had very poor results. In the first place you have got to add a sulphur addition to pick up that copper and once you do that, that sulphur is apt to combine with some of the zinc and you are going to form a little mush; before you know it you have furnace hangs and a poor working furnace. Now of course that depends on the amount of zinc you have on charge. But in 1943, Leadville had roughly about 7 pet zinc in their slag and it worked very poorly. Previously when they had 4 or 5 pet zinc in their slag it did not matter. B. L. SACKETT* At Tooele we had a great deal of experience with copper. We have always been able to keep a lead well, however, in spite of the fact we have run as much as 5 pet copper and only 15 pet lead on the charge. But regarding the handling of dross, our dross reverberatory furnace is only 7 or 8 years old. Before that we recirculated the dross through the furnace and thought we were doing a pretty nice job. Of course these things are all more or less relative—in other words you establish a certain condition much better than one of a few years ago and possibly as good as any other of which you know and you think you have pretty good results. When we first took the dross off of the blast furnace and put it through the dross reverberatory furnace we immediately found out that we had gained something very real in furnace speed. Since that time there have been occasions when, because of the dross reverberatory being down, we have had to use dross again through the blast furnace and that has checked our original experience in slowing down the furnace very definitely. So we feel that a dross reverberatory is a very valuable asset at the Tooele Plant. A. A. CENTER*—Mr. Sackett&apos;s being here reminds me of trying to run with a minimum of lead concentrates the maximum of dross producing electrolytic zinc plant residue. He came up from International Smelting Co. to help us get started on that. We took an old copper blast furnace at Great Falls, Montana, and made a lead furnace out of it by putting a lead well on the other long side which of course is a very unorthodox lead blast furnace. Our aim was to treat the residue from the electrolytic zinc plant, as I said, with a minimum of lead concentrates. That meant a maximum amount of dross. At that time selective flotation was not general practice, so our zinc concentrates ran relatively high in copper and other dross-producing elements; and of course these were largely in the zinc plant residue. I think we might call it muscle metallurgy, but we had an interesting, successful experience there and we ran for over a year thanks to Mr. Sackett&apos;s helping us get started. I have the details, but time does not permit. We did well enough so that the A. S. and R. Co. at East Helena kept boosting up the offer to us for the electrolytic zinc plant residue and there was not enough lead concentrate to supply two lead smelters there in Montana, so the matter finally finished up by the A. S. and R. Co. taking all of the residue under long term contracts.

Jan 1, 1950

By C. W. Chen

MARTENSITE transformations in ß Cu-Al alloys have been studied by Greninger1 and other investigators. According to Greninger, the parent phase ß1 an ordered body-centered-cubic structure obtained from ß phase by suppressing the eutectoid decomposition, transforms into an ordered hexagonal-close-packed phase in composition containing 12.9 to 14.7 pct Al. The M, temperature decreases with increasing aluminum content; for the alloy containing 14.5 pct Al, for example, the ß1??&apos; transformation occurs below room temperature. More recently, Kurjumow2 studied the transformation in ß Cu-Al alloys with the addition of nickel. His report stimulated new interest in the subject due to the observation of completely reversible transformation without hysteresis in the transformation temperature ranging from 10° to —10°C. In the present paper some characteristics are described of the transformation of Cu-Al-Ni alloys that were partly studied by Kurjumow. Experimental Procedure High purity copper (99.999 pct) and aluminum (99.99 pct) and electrolytic nickel were used in the preparation, by the Bridgman technique, of single crystal specimens which contained aluminum and nickel of 14.5 and 0.5 to 3.0 pct, respectively. Polished surfaces were prepared mechanically. Specimens were then chemically etched to remove distorted material, homogenized at 1000°C for several hours, and quenched drastically to room temperature in a 10 pct NaOH bath to produce the parent phase ß1. The transformation was studied under a microscope and, in some cases, recorded by means of motion pictures. A device similar to that designed by Greninger and Mooradian3 was used to cool and reheat the specimens. Results and Discussion When the specimens were cooled below room temperature, the ß1 to ?&apos; transformation began at 10°C with the appearance of ?&apos; crystals In relief, Fig. la. As the specimen temperature dropped further, the transformation continued, either by the growth of the ?&apos; crystals, with the ß1 — ?&apos; interface moving into the ß1 phase, Fig. 1c and 1d, or by the formation of new ?&apos; crystals, Fig. 1b. As a consequence of the former process, banded structure is observed as a common feature of the low temperature phase. According to the theory of the formation of martensite by Wechsler, Lieberman, and Read,&apos; the bands of ?&apos; phase are probably twin-related, as is the case in the diffusionless phase change of In-T1 alloys,5 but this was not revealed by X-ray tech- niques. New ?&apos; crystals, in needle form, often emerged suddenly across the ?&apos; bands during the transformation. These acicular crystals then grew, both in length and in width, see Fig. 2a through 2d. The transformation on cooling is completed at about -35°C. Upon heating, the reverse transformation started at —10° C, in a manner nearly opposite to the transformation on cooling, and completed at 35°C. There was no noticeable change in the transformation temperature when the nickel content was varied within the limits previously mentioned. Through control of the specimen temperature, the transformation can be started, stopped, or reversed at will. This phenomenon has frequently been observed in the martensite transformation of many nonferrous alloy systems. Other systems are Au-Cd6 and In-Tl.5 ow-- ever, in the latter systems, the transformation is accomplished by single interface motion if the specimen composition is homogeneous and the temperature gradient in the specimen is uniform and sharp, whereas in the Cu-Al-Ni specimens, only multiple interface transformation is observed. The speed of the interface motion appears to be a functionof the rate of temperature change and the temperature gradient across the specimen length. In one case, in which the temperature increased at the rate of 10°C per min and there was no temperature gradient along the specimen axis, the speed of the disappearance of a ?&apos; plate was determined, by the study of the motion pictures made, to be 26 µ per sec. Quench markings were observed on the polished surfaces of specimens. The markings were grouped into one or more sets of different orientations, and were parallel in each set. The ?&apos; plates formed in subsequent transformation were parallel to the markings, indicating that the ?&apos; plates and the quench markings had the same geometric relation-ship to the ß1 matrix. The quench markings on two intersecting surfaces of a specimen were therefore used in the determination of the habit plane of transformation, by the trace method suggested by Barrett.&apos; Results obtained from five sets of markings in three specimens indicate that the habit plane is an irrational plane about 2" from one of the {221} planes. This is very close to the habit plane (3" from 221 planes) of ß Cu-Al alloys containing more than 13.0 pct Al.1 The martensite transformation of Cu-Al-Ni alloys is reproducible. No sluggishness was found between consecutive transformation cycles, although a slight difference in the distribution pattern of the ?&apos; plates was observed, compare Figs. Id and 2d. The transformation can be strain-induced. This characteristic has been tested by a simple method. When a specimen was elastically strained slowly in a vise, ?&apos; plates were gradually produced in the same fashion as during transformation on cooling, This test was done at room temperature, and thus above the M,

Jan 1, 1958

By J. R. Schneider

INTRODUCTION Landowners in Texas for many years have freely granted, reserved and leased "oil, gas and other minerals" or interests therein. In recent years we have witnessed much litigation concerning what sub- stances should be included as "other minerals" within the phrase "oil, gas and other minerals," and this question has received the attention of numerous legal scholars. At the South Texas Uranium Seminar held in Corpus Christi, Texas, in September, 1978, Mr. William R. Dodson presented a paper dealing with this very subject and entitled "Uranium - Mineral or Surface? Who Owns It?" In his paper, Mr. Dodson reported on two recent Texas Supreme Court decisions, Acker v. a, 464 S.W.2d 348 (Tex. 1971) and Reed v. Wylie, 554 S.W.2d 169 (Tex. 1977). which held that the particular substance in question in each case is not a mineral within the phrase "oil, gas and other minerals" if substantial quantities of the substance lie so near the surface that production will entail the stripping away and substantial destruction of the surface. Since that time another chapter has been written in the Texas saga of "When is a Mineral not a Mineral?" and it is the intent of this paper to present an update of the Texas law. A review of the early Texas cases so ably covered by Mr. Dodson in his paper will not be repeated, except as is necessary to illustrate the evolution of the legal doc- trine which has been so aptly named "The Surface Destruction Test". BACKGROUND In order to appreciate the genesis of the problem, one must consider that oil and gas production commenced in Texas many years ago, Spindletop came in in 1901. As oil and gas became more valuable, land- owners with considerable frequency sold interest in the oil, gas and mineral estates in their lands, and reserved interest in the oil, gas and mineral estates in their lands when they disposed of their property. Due to the oil and gas background, and perhaps be- cause oil and gas was paramount in the minds of the parties, the traditional language employed in these grants and reservations was "oil, gas and other minerals" or variations thereof. There are literally hundreds of instruments employing this language constituting a link in the chains of title to thous- ands of acres of Texas land. In addition, there are thousands of acres of Texas land held by oil, gas and mineral leases, the primary terms of which have been perpetuated by production, containing similar language in their granting clauses. The severance of the mineral estate from the surface estate results in two separate and distinct estates, each having all of the incidents and attributes of an estate in land. with the surface estate being the serviant estate, and the mineral estate being the dominant estate and having certain easements in the surface estate to explore. produce and remove the minerals. Harris v. Currie. 176 S.W.2d 302, 305 (Tex. 1943). As observed by the court in the Harris case, this is because a grant or reservation of minerals would be wholly worthless if the grantee or reservor co~lld rwt enter upon the land in order to explore for and extract the minerals granted or reserved. Although the Texas law has recognized that an oil and gas lessee has the right to use so much of the surface as is reasonably necessary to produce the minerals. Warren Petroleum Corporation v. Monzingo, 304 S.W.2d 362, 363 (Tex. 1957), recent decisions of the Court have qualified this doctrine. In Getty Oil Company v. Jones. 470 S.W.2d 618 (Tex. 1971). Getty&apos;s pumpine, units were interfering with ones self-propelled sprinkler system utilized for irrigating the premises, and Jones sought to require Getty to install the-pumping units in cellars so that the sprinkler system could pass over them. In an effort to accommodate both the surface estate and the mineral estate, the court held (page 622) "...where there is an existing use by the surface owner which would otherwise be precluded or impaired, and where under the established practices in the industry there are alternatives available to the lessee whereby the minerals can be recovered, the rules of reasonable usage of the surface may require the adoption of an alternative by the lessee". Bearing in mind that the "reasonable use doctrine" grew up in the oil and gas industry involving sub- stances which can be produced by methods that do not destroy or deplete the surface estate, the question presented is whether the Texas courts will extend this doctrine to situations where claimants of "other minerals" seek to produce shallow deposits of iron ore, coal, lignite and uranium by surface mining methods which do destroy or deplete the surface estate? The surface destruction test has answered this question in the negative, at least as to iron. coal and lignite. However, the multitude of mineral estates in Texas which have been created by a grant. reservation or lease of "oil, gas and other minerals" will, doubtlessly, continue to fuel the fires of litigation. EARLY TEXAS DECISIONS In view of the evolution of the Surface Destruc- tion Test, an exhaustive review of the early Texas

Jan 1, 1980