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By Robert S. Dewey

Drilling in West Texas during 1942 was substantially less than in the previous year. In all. 1267 Wells were drilled, as compared with 2325 wells in 1941. Of these 1267 wells, 1052 oil wells, 10 gas wells and 69 dry holes were drilled in proven fields and 36 oil wells, one gas well and 99 dry holes were wildcat operations. Of the 36 wildcat wells completed as oil producers, 16 led to new field discoveries, three found new productive horizons in old fields, and 17 extended the productive limits of established fields. Where semiwildcat drilling took place along established productive trends, there was often no sharp demarcation between wildcat wells that extend field limits and normal development to fulfil lease obligations, other than the arbitrary classification of a well as a wildcat if it was drilled at a distance of 2 miles from a producing oil well. The dry hole drilled on the edge of a field may have proved a more hazardous operation than a semiwildcat drilled several miles from production but favorably located on structure. The percentage of successful wildcatting ranges from 26.5 down to 14 per cent, dependent upon the degree of inclusion of the semiwildcat operations. Irrespective of which figure was used, the West Texas area maintained its better than average exploratory position. No doubt a number of factors may have influenced the extent of the 1942 development. Among those arising from the economic dislocation attendant on the war effort, the following are worthy of note. Owing to inductions into the armed forces and shipyard competition for mechanically trained men, experienced drilling personnel was sharply reduced, thereby increasing drilling costs and well-completion hazards. Replacement labor has not met the same standard of responsibility or workmanship to which the oil industry has grown accustomed. Increased military consumption of aviation gasoline and other crude products, coupled with decreased domestic consumption of lower-octane gasoline, has stimulated the market demand for the types of sweet crude most readily processed with available refinery equipment to meet war requirements, and has depressed the market demand for the sour West Texas crudes. As a majority of the purchasers of West Texas crude normally ship a substantial portion of sour crude to the refineries on the Atlantic seaboard, the loss and diversion of tanker service between Gulf Coast and north Atlantic ports have further curtailed the market demand for this type of crude oil. As some purchasers of crude oil were able to move by pipe line their West Texas trunk-line capacity to Midwestern refining centers, they were not impelled to curtail purchases of West Texas crude. The varying ability of the purchasers of crude oil to market West Texas crude was reflected back to various fields to which they were connected, causing an unequal distribution of production as among fields and operators. The pipe-line runs from the West Texas-New Mexico area decreased from approximately 354,000 bbl. Per day in January to about 265,000 bbl. in December 1942. .Approximately 2,991,000 bbl. of West

Jan 1, 1943

By Robert S. Dewey

Drilling in West Texas during 1942 was substantially less than in the previous year. In all. 1267 Wells were drilled, as compared with 2325 wells in 1941. Of these 1267 wells, 1052 oil wells, 10 gas wells and 69 dry holes were drilled in proven fields and 36 oil wells, one gas well and 99 dry holes were wildcat operations. Of the 36 wildcat wells completed as oil producers, 16 led to new field discoveries, three found new productive horizons in old fields, and 17 extended the productive limits of established fields. Where semiwildcat drilling took place along established productive trends, there was often no sharp demarcation between wildcat wells that extend field limits and normal development to fulfil lease obligations, other than the arbitrary classification of a well as a wildcat if it was drilled at a distance of 2 miles from a producing oil well. The dry hole drilled on the edge of a field may have proved a more hazardous operation than a semiwildcat drilled several miles from production but favorably located on structure. The percentage of successful wildcatting ranges from 26.5 down to 14 per cent, dependent upon the degree of inclusion of the semiwildcat operations. Irrespective of which figure was used, the West Texas area maintained its better than average exploratory position. No doubt a number of factors may have influenced the extent of the 1942 development. Among those arising from the economic dislocation attendant on the war effort, the following are worthy of note. Owing to inductions into the armed forces and shipyard competition for mechanically trained men, experienced drilling personnel was sharply reduced, thereby increasing drilling costs and well-completion hazards. Replacement labor has not met the same standard of responsibility or workmanship to which the oil industry has grown accustomed. Increased military consumption of aviation gasoline and other crude products, coupled with decreased domestic consumption of lower-octane gasoline, has stimulated the market demand for the types of sweet crude most readily processed with available refinery equipment to meet war requirements, and has depressed the market demand for the sour West Texas crudes. As a majority of the purchasers of West Texas crude normally ship a substantial portion of sour crude to the refineries on the Atlantic seaboard, the loss and diversion of tanker service between Gulf Coast and north Atlantic ports have further curtailed the market demand for this type of crude oil. As some purchasers of crude oil were able to move by pipe line their West Texas trunk-line capacity to Midwestern refining centers, they were not impelled to curtail purchases of West Texas crude. The varying ability of the purchasers of crude oil to market West Texas crude was reflected back to various fields to which they were connected, causing an unequal distribution of production as among fields and operators. The pipe-line runs from the West Texas-New Mexico area decreased from approximately 354,000 bbl. Per day in January to about 265,000 bbl. in December 1942. .Approximately 2,991,000 bbl. of West

Jan 1, 1943

Jan 1, 1890

By Wm. Reuben Webster

Brass is an alloy of copper and zinc. The brass containing 70 per cent copper and brasses (using this term to denote all useful 30 per cent zinc. Fig. 3 shows the effect of proportions of the two constituents) are the annealing at various temperatures on the most valuable and widely employed of all same alloy. This effect is somewhat modi- nonferrous alloys, because of their high resistance to ordinary corrosive agencies and the very wide range of properties that may be imparted to them by variations in the proportions of the constituents and by variations in mechanical treatment and heat-treatment. Fig. I shows the normal physical properties, as determined by standard tensile tests, of the series when in the annealed condition. Fig. 2 shows the effect of varying amounts of cold-working on an almost pure fied by the degree of cold-working to which a brass has been subjected, as shown by Fig. 4. A fourth test, which is empirical, has been found useful because of its simplicity —the hot hammer test. Samples 1/2 in. in diameter and 3/4 in. long are placed in a suitable furnace. These are withdrawn one at a time. at successively higher temperatures and are subjected to the blow of a drop hammer weighing 50 lb. with a drop of 4 ft. The percentages of reduction in length of the cylinders are plotted against temperatures and give a camparative measure of plasticity at different temperatures. The results of this test on several

Jan 1, 1942

By Wm. Reuben Webster

Brass is an alloy of copper and zinc. The brass containing 70 per cent copper and brasses (using this term to denote all useful 30 per cent zinc. Fig. 3 shows the effect of proportions of the two constituents) are the annealing at various temperatures on the most valuable and widely employed of all same alloy. This effect is somewhat modi- nonferrous alloys, because of their high resistance to ordinary corrosive agencies and the very wide range of properties that may be imparted to them by variations in the proportions of the constituents and by variations in mechanical treatment and heat-treatment. Fig. I shows the normal physical properties, as determined by standard tensile tests, of the series when in the annealed condition. Fig. 2 shows the effect of varying amounts of cold-working on an almost pure fied by the degree of cold-working to which a brass has been subjected, as shown by Fig. 4. A fourth test, which is empirical, has been found useful because of its simplicity —the hot hammer test. Samples 1/2 in. in diameter and 3/4 in. long are placed in a suitable furnace. These are withdrawn one at a time. at successively higher temperatures and are subjected to the blow of a drop hammer weighing 50 lb. with a drop of 4 ft. The percentages of reduction in length of the cylinders are plotted against temperatures and give a camparative measure of plasticity at different temperatures. The results of this test on several

Jan 1, 1942

By Wm. Reuben Webster

BRASS is an alloy of copper and zinc. The brasses (using this term to denote all useful proportions of the two constituents) are the most valuable and widely employed of all [ ] nonferrous alloys, because of their high resistance to ordinary corrosive agencies and the very wide range of properties that may be imparted to them by variations in the proportions of the constituents and by variations in mechanical treatment and heat-treatment. Fig. I shows the normal physical properties, as determined by standard tensile tests, of the series when in the annealed condition. Fig. 2 shows the effect of varying amounts of cold-working on an almost pure brass containing 70 per cent copper and 30 per cent zinc. Fig. 3 shows the effect of annealing at various temperatures on the same alloy. This effect is somewhat modi- [ ] fied by the degree of cold-working to which a brass has been subjected, as shown by Fig. 4. A fourth test, which is empirical, has been found useful because of its simplicity the hot hammer test. Samples 1/2 in. in diameter and 3/4 in. long are placed in a suitable furnace. These are withdrawn one at a time at successively higher temperatures and are subjected to the blow of a drop hammer weighing 50 lb. with a drop of 4 ft. The percentages of reduction in length of the cylinders are plotted against temperatures and give a comparative measure of plasticity at different temperatures. The results of this test on several

Jan 1, 1942

By U. Andres

U. Andres (The Technion, Haifa, Israel)-The authors are to be congratulated on their research, new and interesting, in a field which, however, the present writer and his assistants have been trying since 1962 to bring to the attention of the scientific and technical world, by means of publications covering several different aspects of this many-sided problem. We announced, in these publications, the results of magneto-hydrostatic (MHD) separation of magnetic and nonmagnetic minerals which we made in magnetic fluids (in paramagnetic solutions and suspensions of magnetic particles) which interact with permanent" and impermanent" inhomogeneous magnetic fields. There is no doubt that the authors have succeeded in creating ferrimagnetic colloids made by dispergation of 10-30 wt % of magnetite in kerosene in the presence of 7-10 vl % oleic acid. It may be judged by [Figs. 3 and 4] that the suspensions represent great stability systems and also "hysteresisless" fluids [(Fig. 5)] which bear witness to the existence of superparamagnetic suspensions. If the viscosity of these colloids is not so high, and the cost of preparing them can be covered, the fluids which have here been received can possibly be of interest to the technology of mineral separation. The potential possibility and technological perspective of similar media is demonstrated in our joint work with G. Bunin18 in 1965. The research carried out on the pushing out of cylinders and spheres from magnetic fluid is impressive; it would, however, have been interesting if the authors had compared their results with those on the pushing out of bodies from magnetic fluids adduced from our work." In my books" there happens to be described an experiment on the pushing out of a sphere in magnetic wedge field, in which the pushing out force of suspension with 5 vl % of magnetite reached 125 g per cc. This testifies to interesting possibilities of these media. Our works' shows also, on the basis of Laplace's equation the receiving of an interesting distribution of pushing out forces by selection of corresponding configurations of magnetic poles. Objection must be made to the authors' introduction of the term "antigravity force." The direction of this force does not depend on the direction of the gravity force and their opposition, i.e., antigravity is only one particular case. I am in full agreement with the authors' statement that magnetic pushing out forces "can be utilized to separate nonmagnetic objects according to variations in their densities." It is, however, necessary to make only one important addition, which can be found in our research on MHS at the Technion in Haifa, namely, that magnetic fluids in magnetic fields can be utilized in the separation of minerals according to variations in their magnetic susceptibility. The authors' conclusion is especially important considering the fact that in our publications" (including one in English") some designs of MHS separators and some technological results received on MHS-separators have already been described. S. E. Khalafalla and G. W. Reimers (Authors' Reply)We were aware (mostly through Chemical Abstracts of the American Chemical Society) of the use of solutions of paramagnetic salts such as manganous sulfate in agnetohydrodynamic separations by the Russian school headed by G. Bunin."n Professor Andres' contributions to this school are also evident in his application of the ponderomotive forces in an electrolyte placed in electric and magnetic cross-fields to separate coal and other useful minerals." It must be realized, however, that the foregoing research by Bunin et al." involved the use of magnetic fields and field gradients of very large magnitudes, i.e., such that H • grad H - 101 Oe2 per cm. The magnetization of paramagnetic salt solutions range from 0.1 to 0.5 gauss (at fields of a few thousand Oersteds) and never reach saturation. The magnetization of our superparamagnetic ferrofluids ranges from 100 to 500 gauss and reach saturation at fields of a few hundred Oersteds. Hence, to effect the same separation, the quantity "H

Jan 1, 1974

THE progress in lead smelting practice in the United States during 1930 has been along previously defined lines. Since most of the material treated is high-grade concentrate relatively high in zinc, practically all the plants have been forced to adopt double sintering. This generally results in there being' no matte fall, and most of the copper in the charge is recovered in the furnace dross. The furnace dross is . smelted with. scrap iron and flux .in small reverberatories, giving a shipping matte or speiss high in copper and low in lead. Details of this reverberatory. furnace practice vary at the different plants. There is a decided tendency toward moreintensive filtration of blast- furnace and sinter fume. Bag capacity has been in- creased by using higher pressures and more frequent shaking.

Jan 1, 1931

By A. E. Brugger

SOME 2,000 years ago Pliny is supposed to have said, "Out of Africa always something new." It may perhaps even now be news to a great many that the Belgian Congo has in recent years been producing approximately a quarter of a ton of diamonds annually. For that is what the 1 1/4 million carats, the recovery from 40-odd operating mines, and about 20 or 25 per cent of the world's normal consumption, amounts to. In 1915, first exploitation operations produced less than 50,000 carats from two mines. The rapid expansion of operations following the Euro¬pean war meant a most rapid development of a virgin land. The interior is now reached by air in one day from the mouth of the Congo River, where steamers unload mail and passengers from Antwerp. This trip formerly consumed 4 to 6 weeks by a narrow-gage, wood-burning, railroad around the rapids of the lower Congo and Livingston Falls; by river boat to the heads of navigation, Djoko Punda on the Kasai or Luebo on the Lulua; and thence by caravan of native porters over narrow-trails to head¬quarters on the Tshikapa. Hundreds of miles of automobile roads have been constructed over veldt and through forest, bridging streams and ferrying rivers. The railway from Capetown to the Katanga copper district to the East, once two months away by trail is now reached in 2 or 3 days over fair automobile highway. Native "boys" who a few short years ago wore little more than a smile and a string of beads and to whom a wheelbarrow was a complicated piece of machinery, are today driving Fords, tending boilers and engines and operating electrical equipment, or are capable mine workmen, machinists and artisans, and dressed in all manner of cast-off white man's clothing. Even as late as 1920, due to difficulties of securing and transporting machinery during and just after the war, the crudest hand operations were the rule for the excavation, sizing, and concentration of the diamondiferous gravel. All washing and concentration is now mechanized, using steam or electric power, and where operations are sufficiently large to permit competition with native labor costs, excavation and transportation are also accomplished by machinery.

Jan 1, 1932

By J. E. Campbell, G. D. Calkins, N. M. Ewbank, M. Pobereskin, A. Wesner

GRINDING for size reduction affects the economics of many processes and products. It is essential as the first step in many industrial processes and is also a finishing step for materials with properties depending on particle size, such as talc, cement, and silica sand. Intermediate and fine grinding are vital operations in the U. S. cement industry, which is producing more than 250 million bbl of cement per year.' Wear of the grinding media is a large part of the grinding operation cost. Problems encountered in grinding cement are so complex that evaluation of efficiency and economy of grinding media is difficult.2 It has been especially difficult to evaluate the relative effectiveness of different types of balls because there are no good testing techniques. Many other industrial operations can be evaluated on a laboratory scale with reasonable accuracy. This does not hold true for evaluation of grinding balls. The consistent results obtained in a laboratory test under a given set of conditions are not always borne out in field application. Rough evaluations of the effectiveness of various compositions and types of grinding balls have been made in the field by using a full charge of one type in a mill and comparing the production record with another run using another type of ball. This method is time-consuming and not very precise, as the second run may not have been carried out under identical conditions. Laboratory-scale tests, on the other hand, have yielded inconclusive results, and many investigators have turned their attention to the development of a field testing technique. Field testing small sample lots of grinding balls has been impractical because it is difficult to identify and recover the test specimens from the grinding mill, and individual groups of balls that have undergone different heat treatments can not be separated.".4 To overcome these difficulties, previous investigators have identified the balls by distinctive marks, notches, and drilled holes, but this procedure has three serious drawbacks: 1) Grinding characteristics and quality of the steel balls may be affected. 2) Physical markings may be worn away in the grinding process, especially during a prolonged run. 3) Recovery from the bulk of the charge will be extremely difficult because the markings are hard to see and may be masked by a coating of the product. To circumvent these difficulties, a radioactive-tracer technique was proposed for recovery and separation of steel grinding balls and subsequent evaluation of the various compositions of the balls. The proposed technique involved five basic operations: 1) Thermal-neutron irradiation activation5 of each group of test grinding balls to a different level of specific radioactivity. 2) Addition of groups of radioactive steel-ball specimens into a ball tube mill. 3) Recovery of radioactive steel-ball specimens from the bulk of the mill charge. 4) Separation of the various groups by their specific radioactivity. 5) Evaluation of actual grinding ball wear. Before any physical tests were performed, required neutron irradiation intensity and time were calculated. Probable composition of the steels to be used was ascertained. An examination was made of the radioactive nuclides8 to be formed which would contribute measurably to the radiation level immediately after irradiation and during the test operation. The radioisotopes formed, their types of radiation, and their half lives are listed in Table I. Of these radioisotopes only iron-59 and chromium-51 were significant for the actual wear test. The intensity of radiation that could be detected by a Geiger counter when the test was completed was the basis for the minimum activation level established. The intensity of radiaton that could be safely handled at the beginning of the test was the basis for the maximum activation level, although this was not considered a major problem. Ten groups of grinding balls of various composition and/or surface or heat treatment were to be tested. One group was designated for the minimum irradiation time. The remaining groups were designated for irradiation periods that increased by increments of 33 pct from that of each preceding group. This difference was considered enough for separation and identification of the groups by comparison of specific activity. Potential Hazards: Possible radiation hazards that might be encountered during this experiment were evaluated for the three important phases: 1) the radiation hazard of placing balls and removing them from the mill, 2) contamination of the product cement by radioactive material worn from the balls, and 3) contamination of the steel by the radioactive balls left in the mill. The radiation intensity expected from the whole group of radioactive balls was calculated to be 250 milliroentgen per hr at 1 ft. This meant the balls would require special shielded packaging and warning labels on the shipping containers. In a radiation field of 250 mr per hr a man can work for 1 hr without exceeding maximum permissible weekly exposure. Since the balls could be dumped into the mill in a matter of seconds, relatively little radiation exposure was anticipated at this stage of the operation. If the weight loss in the balls was 7.7 pct per month and the cement feed through the mill was

Jan 1, 1958

By O. E. Kiessling

THE Committee-on Production Control, at its meeting held during the last annual session in February, 1930, evidenced great interest in problems of stabilization affecting all mineral industries. . No immediate program of activity for the Committee as a- unit was decided on, however,, and efforts during the past pear have consisted lirgely of further stressing the economic aspects of mineral production and of the action by committee members, :.serving in their individual capacities, in sponsoring constructive changes, in specific, industries. Of greatest interest to the general subject of production control in 1930 was the very definite advance toward better coordination of demand and supply in the petroleum industry. Furthermore, since opinion both within and without the oil industry now favors a constructive program, and with a gradual change in legal precedents, it seems not unreasonable to expect greater progress in the near future.

Jan 1, 1931

By Lawrence Adler

MINE hoist ropes have hitherto been selected by successive approximation, a process both tedious and inexact. The proposed expression is a readily solved synthesis of existing data and the following standard equation:' [ W + Wr + (W + Wr) -a 9 (W + W)f + b] n=T [1] For convenience, a glossary of all terms appears on page 564. Since rope weight (W,) and bending load (B) are functions of unit rope weight (Wv), which in turn is a function of rope strength (T), W, and B can be expressed in terms of T. W, as a Function of T: A study of the curve in Fig. 1, unit rope weight vs strength, yields Eq. 2: W. = -f- [2] Therefore Wr = WvL = T. [3] iv B as a Function of T: From Fig. 2, unit rope weight vs diameter, Eq. 4 is obtained: W, = 1.6d2 [4] B is related2 to d and D, and d has been expressed in terms of W, by Eq. 4, so the curve B vs W, (Fig. 3) gives Eq. 5: 177,000 177,000 This may readily be checked from the expression3 for a 6x19 rope, i.e., d3 B = 288,000D Since d2 = 0.625 W, and N = substituting d into the above expression gives Ea. 6: 180,000 180,000 B T, which will be used. [6] Into Eq. 1 substitute Eq. 3 and Eq. 6, noting that f=0.02: W + T 1.02+=T. [7]

Jan 1, 1958

By M. B. Bever, A. K. Jena

THE heats of formation ?H at 273°K of the compound AgMg as a function of composition have been measured by solution calorimetry.1 The value at the stoichiometric composition is -4.41 kcal per g-atom. From electromotive force measurements2'3 the heat of formation at 773°K of stoichiometric AgMg has been determined as -5.19 kcal per g-atom.4 The combination of these two values results in an unusually high negative temperature coefficient of the heat of formation d?H/dT = ?Cp = -1.6 cal per g-atom-OK. By contrast, published heat contents of the compound AgMg and the component elements above room temperature5 indicate that the temperature coefficient of the heat of formation of AgMg is nearly zero. In this communication calorimetrically measured heats of formation of A.K.JENA,Junior- MemberAIME,andM.B. BEVER,Member AIME, are Staff Member, Division of Sponsored Research, and Professor of Metallurgy, respectively, Massachusetts Institute of Technology, Cambridge, Mass. Manuscript submitted July 1, 1968. IMD AgMg below room temperature are reported and the temperature dependence of the heat of formation is discussed. The heat effects of additions of samples of the compound AgMg containing 50.1 at. pct Mg to liquid tin-rich solutions at 623°K were measured in a solution Calorimeter.6 The heat effects of additions plotted against the average of the atom fractions of solutes in the solution before and after each addition were a linear function of composition from which the heat effect at infinite dilution was obtained, Table I. The calorimeter was calibrated by additions of tin; the heat content (H623°K - H273°K) of tin was taken as 4.08 kcal per g-atom.4 The heat effect at infinite dilution of an addition of where heat of formation of AgMg at T°K, T = temperature from which samples are added (78°, 195°. and 273°K), Xi = atom fraction of i in AgMg, ?Hi = relative partial gram-atomic enthalpy of i in tin-rich solution.

Jan 1, 1969

By John A. Graves

Anaconda's Jackpile-Paguate mine, located between Albuquerque and Grants, N.M., is situated at an elevation of 6000 ft in a semi-arid desert region. The original Jackpile deposit was discovered by Anaconda air and ground exploration parties in Nov. 1951. A large percentage of the uranium mined in New Mexico comes from the Jackpile-Paguate, which is one of, if not the largest, open pit uranium mines in the world. From 1953 to the present, 120 million tons of overburden, mining waste, and low-grade material have been removed to produce approximately 10 million tons of merchantable uranium ore, having an average grade of about 0.25% uranium oxide. Identifying the Orebody Surface drill holes delineate the ore bodies on a predetermined grid which varies in dimension but usually affords 100-ft control. These holes are probed immediately after drilling by geophysical logging trucks, resulting in a gamma log and digital readout from each hole. From this information it is possible to arrive at an almost immediate conversion to percentage of U3O8 on 6-in. intervals. Initially a hole is probed at a reconnaissance speed of 10 fpm with a time constant of 8 sec. Wherever the gamma recording goes off scale on an initial run, that particular zone is rerun at 2 fpm and at a time constant of 2 sec. This time constant is the interval that emissions are counted and accumulated for recording purposes. The search radius of the Geiger probe is approximately 18 in.

Jan 8, 1974

By Raymond Mancha

The use of blower fans and tubina- for auxiliary face ventilation is a somewhat controversial subject. Most authorities agree upon the advantages of this system over the maintenance of line brattice for dead-end ventilation. They also recognize the system's disadvantages. However, there is considerable disagreement as to the proper relation of the advantages to the disadvantages. It is the purpose of this report to present the opinions of four authorities of diversified occupation and permit the reader to form his own opinions on the subject. ORsErvers Carel Robinson is a mining engineer consultant of wide repute, who has a background of operating experience. Thomas G. Fear is a mine operator whose present position is that of chief engineer for the Hanna Coal Co. at St. Clairsville, Ohio. E. H. Denny is chief of the Coal Mine Inspection Division of the U. S. Bureau of Mines, and is a very able engineer whose past experience well qualifies him to appraise this problem. Cloyd M. Smith, editor of the periodical Mechanization, is a ventilation consultant. For a number of years he was a member of the Mining Department of the University of Illinois and has studied mine ventilation for many years. It is Mr. Robinson,s opinion that closely spaced breakthroughs, although conducive to low gas accumulation past the last open crosscut during the driving of entries, are difficult to maintain and are constant Sources of fugitive air. Jute or canvas brattice is suitable for entry driving with

Jan 1, 1944

By Raymond Mancha

The use of blower fans and tubina- for auxiliary face ventilation is a somewhat controversial subject. Most authorities agree upon the advantages of this system over the maintenance of line brattice for dead-end ventilation. They also recognize the system's disadvantages. However, there is considerable disagreement as to the proper relation of the advantages to the disadvantages. It is the purpose of this report to present the opinions of four authorities of diversified occupation and permit the reader to form his own opinions on the subject. ORsErvers Carel Robinson is a mining engineer consultant of wide repute, who has a background of operating experience. Thomas G. Fear is a mine operator whose present position is that of chief engineer for the Hanna Coal Co. at St. Clairsville, Ohio. E. H. Denny is chief of the Coal Mine Inspection Division of the U. S. Bureau of Mines, and is a very able engineer whose past experience well qualifies him to appraise this problem. Cloyd M. Smith, editor of the periodical Mechanization, is a ventilation consultant. For a number of years he was a member of the Mining Department of the University of Illinois and has studied mine ventilation for many years. It is Mr. Robinson,s opinion that closely spaced breakthroughs, although conducive to low gas accumulation past the last open crosscut during the driving of entries, are difficult to maintain and are constant Sources of fugitive air. Jute or canvas brattice is suitable for entry driving with

Jan 1, 1944

THE CHAIRMAN (H. W. MORSE, Los Angeles, Cal.).-I would like to open this meeting for a little while to the general subject of leaching. We ought not to hold back if we have any new schemes for the future. I know that those of us who are tangled up with this lei thing work will appreciate any suggestions that will make us work harder and, scheme, harder to pull through these past difficulties on leaching. F. S. SCHIMERKA, Clifton, Ariz.-Under the direction of J. W. Bennie, General Manager of the Shannon Copper Co., Clifton, Ariz., 'it has been my valued privilege to cooperate in the elaboration of a hydrometallurgical process aiming at the recovery of copper in mill tailing resulting from a gravity concentration of a low-grade semi-oxidized sulphide ore occurring in a porphyritic gangue. The experimental work which has been carried on with a 25-ton plant is completed, and the company is building at present a leaching plant on a larger scale, the first unit consisting of a 150-ton roasting furnace and accessories for leaching the calcine.

Jan 12, 1916

Jan 1, 1908

By Joseph W. Richards

The Ashio copper-mine of the Furukawa Mining Co. is situated 18 miles from Nikko, and 109 miles north of Tokyo, near the center of Japan. The mine-waters are run over scrap-iron, whereby most of the copper is precipitated as cement-copper, leaving iron sulphate with some copper sulphate in solution. After using in the wet concentrating ore-dressing plant, the waste water contains clay and ore-slimes. The only avenue of disposal of this water is the Watarese river; but as this flows through valleys in which the water is used for irrigating the rice-crops, it is necessary to purify and clarify the water before discharge. The water amounts to from 600 to 700 cu. ft. (from 17 to 20 cu. m.) per minute, and averages about 0.00028 per cent. of copper, representing more than 18 tolls of copper per month. The water carries H2SO4, FeSO4, Fe2(SO4)3, CuSO, and other metallic sulphates in solution, and clay, ore-fines, slimes and basic iron sulphates as suspended matters. To purify and clarify the water, precipitation by milk of lime has been used, in three different ways, as follows: I. First Method, Copper not Recovered. Milk of lime was run into the water, and the mixture run through six settling-ponds, and then through a sand filter into

Jan 1, 1913

By AIME AIME

NO MORE SUITABLE time and place than LOS Angeles on Thursday and Friday, July 28 and 29, could have been chosen for the Western Regional Meeting of the~1nstitutk. After attending two clays of technical sessions and enjoying the luncheons and dinners of the meeting, visitors, on the following days, could see the opening ceremonies and events of the Olympic Games, which started on July 30 and continued to Aug. 14. Such d spectacle can be seen only once in a generation in this country.

Jan 1, 1932