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By S. W. MEALS

TWENTY million people in this country and Canada in nearly four million homes can give thanks to our Creator for natural gas, that most wonderful natural fuel with which Dame Nature has so bountifully blessed us. It is a clean, healthy and cheerful fuel, made up almost entirely of carbon and hydrogen. There is no residue, no waste and there are no objectionable constituents; an ideal fuel for the home. It operates like magic, open the valve and it is there for your needs, winter or summer, night or day. You are not required to place your order 30 to 90 days in advance and you do not need to pay for your winter's supply in advance. No ashes to worry about, no flues or chimneys to clean, nor kindling wood to store or bother the housekeeper. We who have been so blessed do not realize what it would mean to be without it. If in place of opening a valve we had to go to the woodshed or coalhouse and then build our fire-carry out the ashes-well, some of us I am afraid would be late reaching our offices and perhaps would miss our hot cakes for breakfast. One cubic foot of gas produced from the White Sand formation contains 1130 B.t.u. and weighs 47/1000 lb.; there are about 24,000 B.t.u. in 1 lb. of gas. Temperatures of over 3400 deg. Fahr. have been obtained with natural gas. Not only is it a superior fuel for the home but it has no equal for use in many large manufacturing industries, especially with the making of glass, pottery and open-hearth steel. In an open-hearth furnace, properly constructed, 5000 cu. ft. will melt one ton of steel. It requires 1/3 ton of bituminous coal gasified in a producer to do the same work, or about 40 gal. of tar or fuel oil, or 11,000 cu. ft. of by-product gas.

Jan 1, 1926

By George A. Roche

Investment in growth stocks is the most assured way of achieving superior, long term investment accomplishment. There are many criteria used to select growth companies but the most important is a combination of superior management operating in an industry with above average growth potential. This growth stock approach is the cornerstone of investment strategy for two of the three mutual funds sponsored by the Price organization and for its private clients. However, during the past five years inflation has accelerated due to a variety of factors including the inability of government to meet seemingly unlimited needs with limited revenue sources.

Jan 4, 1972

By T. A. Rickard

Slovenliness is as reprehensible in words as in clothes. Much writing that we recognize as poor in style is merely sloppy. Just as some students postpone the necessary shave or forget to change their collars, so young engineers in writing drop their articles, definite and indefinite, or omit prepositions where they are required, possibly to compensate for these they use unnecessarily The work will begin [on] Saturday. The work will begin [on] Saturday. `Influenza seriously affected many mines [during] the last three months. Flotation in America [during] the last two years has made tremendous strides. Construction of the mill started [on] August 12, 1915, at which time 75% of the excavation was completed. The idea I wish to convey is [that] there are mineral deposits to which the present law applies badly. For this reason, if there was [for] no other, the ownership of the ore below and [of] the surface above should go together. When a unit of mapping is furnished, be the unit a claim or [a] group of claims, it is necessary .. . A fully stocked store was started in Park City and all employees [were] sold merchandise on a strictly cost basis. The word "merchandise" is left without government or agreement. I suggest: ". . . and merchandise] was sold to all the employees on a strictly cash basis.". The verb `be' is serving concurrently both as a principal and as an auxiliary in the following: At first the work was interesting and [was] liked by most of the men. The sulphide ore was more complex or [was] milled at an increased cost. The failure to repeat tie auxiliary verb in successive clauses is a common error, as in The filter is filled with liquid allowed to empty, and then ignited.

Jan 1, 1931

By Warren W. Jamar, Philip D. Pearson

IN recent years, there have been many changes in mining operations in the Lake Superior district. To follow these trends on the Menominee Range of Michigan, information has been assembled from all of the iron informatior]mining operations in the area. There are 15 operating underground mines in the Iron River-Crystal Falls area of the Menominee Range. Within the past two years, two idle properties were reopened pasttwoyears,and are now producing, and a third and fourth are being reopened. Also, there are two siliceous openpits operated by independent companies outside this immediate area. Six companies operate the underground mines, employing some 1850 employees. Table I shows pertinent facts about these properties. During 1949, the largest mine in Iron County shipped 571,287 tons, and one of the newer mines shipped 39,378 tons, with a range total to 3,535,-373 tons. Since the Menominee Range was opened in the 1870's, the mines in Iron County have shipped 85,890,922 tons. From an operator's viewpoint rather than a geologist's, the ore is' classified as semi-hard, composed of hematite and limonite. It is not as soft as the ores of the Marquette Range nor is it as hard as the hard ores of the Marquette and Vermillion Ranges. The ore bodies have slate hanging walls and slate footwalls. In most cases the hanging walls and footwalls are soft and high in sulphur. The sulphur comes from pyrite, and these slates will ignite when piled more than 6 to 8 ft high. Ore is mined on this range by: 1—Sub-level stop-ing; 2—Shrinkage stoping; 3—Sub-level caving; 4— Block caving; 5—Top slicing. The predominance of these methods is in the order named. Underground drilling is important in the mining cycle. Some changes made and trends toward future changes fall into four categories: Drill bits, drill steel, drill machines, and compressed air pressures. Several types of bits have been tried and are in use. They include the detachable tungsten carbide, insert bit; the intraset steel bit, which is a conventional steel rod with tungsten carbide insert; the one-use bit; and the multiple-use bit. For many years, detachable multiple-use bits have been standard. In tests conducted recently to im- prove drilling efficiency, this bit was used as the basis for comparison. Under existing conditions, a multiple-use bit can be resharpened about three times before it is discarded. A thorough test of 2-in. tungsten carbide threaded bits was conducted under various ground conditions. 1—The drilled footage ranged from 48 to 600 ft per bit; averaging 357 ft per bit. Under these same conditions, a multiple-use bit ranged from 8 to 80 ft per bit. 2—The bit cost was greater for the insert bit in each case. 3—The average drilling speed for the insert bit was 12 in. in 62 sec and for the multiple-use bit was 12 in. in 64 sec. In a second test, 2V4 -in. tungsten carbide bits with the large 1 3/16-in. thread were used in moderately soft ground on a 152-lb drifting drill on a long feed jumbo. 1—The drilled footage ranged from 450 to 5000 ft per bit, averaging 1810 ft per bit. Under these same conditions, a multiple-use bit averaged 64 ft per bit. 2—The bit cost was reduced by the use of the insert bit. 3—No increase in drilling speed was recorded. 4—Minimum footage obtained was caused by thread failure. To improve the thread life, thread size on the rod was increased and the bit was attached to the rod with a pipe wrench. After this, bits failed in equal proportions because of cracked skirts, broken inserts, and gage loss. Tungsten carbide bits are now used in the operation where this second test was conducted because labor costs were lowered as a result of reducing the number of bits being changed by the miners. At the same operation and under the same conditions as the second test, 1Y4-in. insert bits with standard 1-in. threads were used. These bits did not drill much more than 300 ft before thread failure and were then welded to the rods and used until total failure. Sometimes this footage was considerable, sometimes it was not. Chisel-type 2%-in. insert bits were

Jan 1, 1952

By K. R. Janowski, H. Conrad

As part of a program to establish the effect of crystal imperfections on laser output, a detailed study was made of the dislocation structure of ruby crystals obtained from varioius sources. Using KHSO4 as an etchant, a detailed mapping of the dislocation structure on the (0001) and the (1150) planes was carried out. A less extensive study was made of the rhombohedral planes. The average dislocation density on the basal plane was 1.5 to 3 x 106 cm&apos;2 and on the (1120) planes -5 x 10&apos; cm-2. Howe7!er, considerable variation existed between areas on a given plane. The subboundaries in the basal plane tended to lie along [1100] type directions while those on the (1120) plane tended to lie: a) parallel to the basal plane, b) along truces of the (1101) plane, and c) along normals to the traces of the (0001) planes. The orientations suggest that mang of the dislocations lie on the (0001), (1701), and (1150) planes A Laue back-rellection nnalysis Of c-axis wander in one crystal revealed a gradual increase in misorientation from me end of the crystal to the other, with a maximum variation of 1°35&apos;. Slight etching of a mechanically polished crystal revealed mumerous polishing scratches, suggesting the existence of a plastic flow layer. It is recognized that chromium concentration, lineage, and other crystalline imperfections play a role in the efficiency of ruby lasers.&apos; Consequently, it is desirable to establish in detail the imperfection structure of ruby crystals to be used as lasers. Some exploratory work along this line had already been done by Barnes&apos; and Dils and Martin.&apos;" How- referred to as the morphological system, as described by Kronberg.4 The Miller indices given in the present paper will be based on this morphological system. In this system, the three common growth planes are the (0001), the {1120}, and the {1101}.5 Since these planes are of high stability, it is expected that they are most suitable for study by the etch-pit technique. In the present investigation, a detailed mapping of the dislocation structure was carried out for the (0001) and the (1130) planes. A less extensive study was made of the etch-pit structure on rhombohedra1 planes. An analysis of dislocations in sapphire (the ruby host) was first made by kronberg,4 who postulated that slip on the (0001) plane occurred by motion of dislocations with Burgers vector 1/3 <1150> and that these dislocations might dissociate into quarter partials. An etch-pit technique using boiling phosphoric acid was developed by Scheuplein and Gibbs6, 7 for identifying dislocations intersecting the (0001) planes and the planes near (2021) in sapphire. Al-ford and Stephens8 were able to reveal dislocations on the (0001) and {1120} planes in sapphire and ruby by etching in fused potassium bisulfate (KHS04) at 675°C. The termini of basal dislocations [(000l), <1120>] were revealed by Palmour and Kriegel9 on {1120} and {1010} by thermally etching sapphire. Bond and Harvey10 were able to decorate dislocations in sapphire by adding 1 pet by weight of ZrO2 to the Al2O3 powder used in the growth of the crystals by the Verneuil technique and then heating the grown crystals for 4 hr at 1500°C. They found, using optical transmission microscopy, that many dislocations had straight segments which were parallel to one of the six [1120] directions in the basal plane. Single dislocation lines curved smoothly from one alignment to the other, turning through angles of 60 to 120 deg. Also observed were isolated hexagonal loops, approximately 10 µ in diameter, the sides of which lay along the same directions as did the longer dislocations. MATERIAL AND ETCHING PROCEDURE The ruby specimens used in this study (all containing approximately 0.04 pet Cr) had been obtained from four different sources: Linde Co., Meller Co., Valpey Crystal Corp., and those grown at Aerospace Corp.* For the initial phase of this study, several specimens were cut from the slab shown schematically in Fig. 1 which had previously been cut from a disk boule obtained from the Linde

Jan 1, 1964

By E. R. Palowitch, P. H. Broussard

The United States aims to achieve some modicum of energy self-sufficiency through means such as conservation, increased domestic oil and gas production, substitution by the electric utilities of coal or coaloil mixtures for oil and gas, and development of a viable synthetic liquid fuels industry. Coal&apos;s role in attaining this goal will necessitate doubling coal production by the end of the 1980&apos;s. And if the United States does in fact become the World&apos;s Saudi Arabia of coal, the total annual production to meet these domestic needs and export markets could double again by the year 2,000. As only a small portion of our Nation&apos;s reserves are recoverable by state-of-the-art surface mining methods, most of the coal produced in the future will have to be mined underground (Averitt, 1975). But this projected increase in coal demand is occurring in the face of a decade of radically decreasing productivity. Specifically, average worker productivity in underground coal mines has decreased from 14.2 tonnes (metric tons) per workershift in 1969 to 7.2 tonnes per worker-shift in 1979; and 95 percent of coal produced underground during this period was produced by room-and-pillar methods (U.S. Dept. of Energy, 1980). Although there is no complete agreement on the impact of recent Federal legislation, there is strong correlation between the dramatic decrease in productivity in underground coal mining and the implementation of the recent Federal mine health and safety regulations (U.S. Congress, 1969). A review of the wide range of coal mining research, development, and demonstration projects currently being funded by the federal government and by industry gives little encouragement for increasing worker productivity on room-and-pillar sections underground in the immediate future (Palowitch, 1978). Conversely, the opportunities for increasing production/productivity underground with longwall methods appear somewhat more encouraging. Although at least one longwall face in the U.S. did produce more than one million tonnes of coal in a single year, the national two-shift average production from one hundred or so longwall faces is about 1,000 tonnes per day (Huwood-Irwin Co., 1978 and Consolidation Coal Company, 1976). Clearly, there exists some real opportunities for improvement. One of these opportunities is to automate the cutter-loader.

Jan 1, 1981

By D. J. McAdam, G. W. Geil, D. H. Woodard, W. D. Jenkins

INTRODUCTION IN a series of papers, the authors and their associates have shown that the resistance of a metal to fracture is a function of all three principal stresses. 10-18,20,21,23,[1] Consequently since a technical cohesion limit is defined as the technically determinable resistance to fracture, under a specific stress system, the technical cohesive strength comprises an infinite number of technical cohesion limits corresponding to the infinite number of possible combinations of the principal stresses. As shown in the previous papers, the technical cohesive strength increases with plastic deformation, with decrease in temperature, and with increase in the strain rate. The technical cohesion limit, therefore, is affected by the same factors that affect the flow stress,§ namely, the stress system, plastic deformation, temperature, and the strain rate. The effect of each of these factors on the fracture stress is qualitatively the same as its effect on the flow stress. The effect of any of the factors may be represented by a curve of cohesion limits, although only one point on the curve may represent actual fracture. Since the term "fracture stress" has come into general use with the same significance as technical cohesion limit; the authors are here using the&apos; shorter term with the understanding that it, does not always refer to actual fracture. In the general investigation described. in the previously-mentioned papers,10-18,20,21,23 the influence of the stress &apos;system on the fracture stress was studied by means, of tension tests of notched specimens. When a circumferentially notched cylindrical&apos; specimen is subjected to longitudinal ten-, sion, the minimum cross section is under " transverse radial tension. The mean radial stress increases with the depth and sharpness of the notch, but is always less than the longitudinal stress. The greatest principal stress (S,), therefore, is longitudinal, and since the radial stress is effectively equal to the circumferential stress, the transverse principal stresses are equiaxial in that plane (S2 = S3). By the use of notched specimens in tension tests it was shown that the fracture stress increases with increase in the radial stress ratio (S3/SI). The evidence is based not only on the results of tests to fracture at various constant temperatures, but also on. results of two-stage tests, in which each specimen was plastically deformed a predetermined

Jan 1, 1948

By D. J. McAdam, G. W. Geil, D. H. Woodard, W. D. Jenkins

.In a series of papers, the authors and their associates have shown that the resistance of a metal to fracture is a function of all three principal stresses. Consequently since a technical cohesion limit is defined as the technically deter-minable resistance to fracture under a specific stress system, the technical cohesive strength comprises an infinite number of technical cohesion limits corresponding to the infinite number of possible combinations of the principal stresses. As shown in the previous papers, the technical cohesive strength increases with plastic deformation, with decrease in temperature, and with increase in the strain rate. The technical cohesion limit, therefore, is affected by the same factors that affect the flow stress,$ namely, the stress system, plastic deformation, temperature, and the strain rate. The effect of each of these factors on the fracture stress is qualitatively the same as its effect on the flow stress. The effect of any of the factors may be represented by a curve of cohesion limits, although only one point on the curve may represent actual fracture. Since the term "fracture stress" has come into general use with the same significance as technical cohesion limit, the authors are here using the shorter term with the understanding that it does not always refer to actual fracture. In the general investigation described in the previously-mentioned papers, 10-18,20,21,23 the influence of the stress system on the fracture stress was studied by means of tension tests of notched specimens. When a circumferentially notched cylindrical specimen is subjected to longitudinal tension, the minimum cross section is under transverse radial tension. The mean radial stress increases with the depth and sharpness of the notch, but is always less than the longitudinal stress. The greatest principal stress (S1), therefore, is longitudinal, and since the radial stress is effectively equal to the circumferential stress, the transverse principal stresses are equiaxial in that plane (Sz = S3). By the use of notched specimens in tension tests it was shown that the fracture stress increases with increase in the radial stress ratio (s3/s1) The evidence is based not only on the results of tests to fracture at various constant temperatures, but also On results of two-stage tests, in which each specimen was plastically deformed a predetermined

Jan 1, 1949

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

The paper reports the development of a large, slow speed ball mill closed circuited with a hydroscillator. This increased grinding efficiency 28 pct over conventional units.

Jan 1, 1950

By N. H. Emmons

(Canal Zone Meeting, November, 1910.) AN interesting development of copper blast-furnace construction has been brought about in adapting the blast-furnace to be a "burner" for sulphuric acid making. When the Tennessee Copper Co. first decided to construct an acid-plant, the standard type of brick-top furnace, supported by structural steel, was the only one in use at this plant. All the tests for temperature and strength of gas had been made on these furnaces, and had been satisfactory. When, however, the acid-plant was put on the flue, and the flue had to have a damper put in it to force the gas into that plant, troubles began. The furnaces were fairly tight, and for a few months the work was quite satisfactory., Fig. 1 shows the old type of furnace-top used at the start. It was soon found that this top would not stand the temperatures, particularly when dampered back, as was necessary to force the gas into the Glover towers. The structural steel, of which the furnace skeleton was constructed, warped and twisted so badly that it was not safe to use the furnaces. This effect is shown by Fig. 2, which is a photograph of old No. 4 furnace, after the brick-work had been removed. It became apparent that a new type of top was necessary and the engineering force was started oil the design of a new furnace-top, with the result that a low top, with brick-lined flues at each end below the feed-floor, leading to the main concrete dust-chamber, was constructed. This furnace, No. 7, is shown in Fig. 3. The charging-doors are made of cast-iron sections, three sections to a door, and three doors to a side. A door to the furnace was made of cast copper, but the heat was so great that the copper bent readily, due to the jarring of its * General Manager, Tennessee Copper Co.

Feb 1, 1911

By Eric S. Cheney

Sulfur isotopes are best used in conjunction with other geological studies to determine the origin of known deposits; concept-oriented exploration programs can then be developed to find similar deposits. Geochemical processes are capable of causing different S &apos;41S" ratios in the minerals and fluids participating in natural reactions. Because the magnitude of the resultant isotopic difference is inversely proportional to temperature, sulfur isotopic studies can be used to determine the source of the sulfur in high temperature deposits. The narrow spread of sulfur isotopic values from ores related to cupolas of felsic intrusions suggests that the sulfur in the ore-forming fluids was derived from a fairly uniform source (such as the intrusions) rather than by heated ground water from the adjacent country rocks. However, geologic and isotopic evidence suggest that the sulfur of many nickel sulfide ores may have been derived from the country rocks rather than the associated mafic igneous rocks. This sulfurization hypothesis implies that mafic intrusions in sulfur-rich country rocks should be prime exploration targets. Sulfur isotopic analyses of sulfides in the mafic rocks may indicate whether sulfurization has occurred. In equilibrium geochemical reactions S" is concentrated in the minerals with the greater bonding strengths. Thus the isotopic compositions of coprecipitated sulfides that have not undergone exsolution may be used as geothermometers and to distinguish multiple periods of mineralization, post-ore metamorphism, etc. The sulfur isotopic compositions of coexisting sulfides at Butte, Mont., indicate that the copper minerals did not originate by simple replacement of pyrite. Geologic and isotopic evidence suggest that the mineralogical and isotopic zoning at Butte formed almost isothermally during the geochemical evolution of the ore-forming fluids upward and outward from the Central zone. Unidirectional reactions cause enrichment of S" in the products. At low temperatures the isotopic effects of bacterial and inorganic reactions are difficult to distinguish. Anaerobic sulfate-reducing bacteria apparently were responsible for the sulfur of Gulf Coast salt domes and for diagenetic pyrite in sandstone-type uranium deposits. Sulfur (and carbon) isotopic data suggest that the roll ore bodies of sandstone-type uranium deposits originated by limited inorganic oxidation of diagenetic pyrite rather than by bacterial activity. Accordingly roll ore bodies should be most numerous and thickest against those portions of the sandstone aquifer that contain pre-ore pyrite.

Jan 1, 1975

By A. Bar-Or, G. Hirsch, P. Wynblatt

The rates of nucleation and growth at various temperatures in U-0.45, 1.1, and 1.35 at. pet Cr alloys were determined, providing a qliantitative proo-f that the transformation under study is controlled by nucleation and diffusional growth. The linear relationship, log NV US 1/T2, suggests that the nucleation of the alloys is probably controlled by the classical law of nuclei formation. The established linear relationship, log G us 1/T, in the three alloys suggests that growth in each alloy is controlled by bidimensional nuclei formation. It was established that both the rate of growth and the rale of nucleation are retarded by chromium. Using classical formulae, sApN and sApG (the ß/a apparent interphase energies) were calculated from the nucleation and growth results, respectively. It was found that their values are of the same order of magnitude. However, why sApN is unaffected by the addition of chromium, while sApG increases with it, needs further clarification. In the last few years, an appreciable amount of research has been conducted into the mechanism of the ß —a transformation in uranium and uranium alloys. Recently, Burke1 reviewed the published work concerned with this transformation. He concluded that in dilute uranium alloys it is firmly established that, at high temperatures in the a range, ß decomposes by a diffusional process. However, he based his conclusion either on experiments dealing with the over-all transformation,2 or on qualitative results.3 It was felt that a better insight into the mechanism of transformation could be gained from the quantitative measurements of growth and nucleation rates, which we aimed to carry out in the present work. In a previous work,4 we have shown that a rim of a grains is formed during isothermal transformation at the high a range. The thickening of this rim with time was used for measuring the rate of growth in U-0.45 at. pet Cr.5 This method was also used in the present work for two more alloys. For meas- uring the rate of nucleation, a method of quenching and macroetching was developed to allow differentiation between a grains formed during isothermal transformation at the upper a range and those formed after quenching, Fig. 1. EXPERIMENTAL WORK AND RESULTS The Rate of Nucleation. The measurement of the rate of nucleation was effected by counting the num-

Jan 1, 1965

By E. I. Larsen, E. F. Swazy, F. R. Hensel

High strength, high-conductivity copper-base alloys have found considerable use in the resistance welding and electrical industry in the form of castings, forgings, or wrought products. There are a number of parts utilized by these industries which would lend themselves to manufacture by powder metallurgical methods provided the required physical and electrical properties are obtainable with such methods. The present paper describes the results of a study of certain copper-base powder metallurgical products susceptible to precipitation hardening. Copper Powders The general types of commercially available copper powders are flake, spherical and electrolytic. Micrographs of these three types are shown in Figs. I, 2 and 3. The difference in particle shape is pronounced and obvious. The type of powder used is determined, or at least indicated, by the final properties desired in the finished article. The type of powder employed during the present investigation was electrolytic powder shown in Fig. 3, and was chosen because of its particular adaptability to the work described in this Paper. The screen and chemical analyses of this powder are shown in Table I. In the preparation of compacts of high electrical conductivity, the purity of the copper powder is of importance in addition to other factors, such as density and the state of internal stresses. These variables were studied briefly by pressing a number of compacts to various pressed densities, sintering them for one hour in hydrogen at 975OC and repressing. The size of the finished compacts was 1/4, by % by 8 in. The time interval from the application to the termination of pressure was approximately 20 sec. Some of the compacts were annealed before testing. The results are listed in Figs. 4 to 8, inclusive. In Fig. 4 the curves of pressed density vs. compacting pressure, and sintered density versus compacting pressure show the typical direct relationship of pressure and density. Compacting pressures exceeding about 30 tons per sq. in. result fiequently in expansion during sintering for the type of powder used. Fig. 5 indicates that variations in the initial pressed density within the range of about 5 to 6 grams per c, c., affect only slightly the pressure required to obtain a

Jan 1, 1946

By E. I. Larsen, E. F. Swazy, F. R. Hensel

High strength, high-conductivity copper-base alloys have found considerable use in the resistance welding and electrical industry in the form of castings, forgings, or wrought products. There are a number of parts utilized by these industries which would lend themselves to manufacture by powder metallurgical methods provided the required physical and electrical properties are obtainable with such methods. The present paper describes the results of a study of certain copper-base powder metallurgical products susceptible to precipitation hardening. Copper Powders The general types of commercially available copper powders are flake, spherical and electrolytic. Micrographs of these three types are shown in Figs. I, 2 and 3. The difference in particle shape is pronounced and obvious. The type of powder used is determined, or at least indicated, by the final properties desired in the finished article. The type of powder employed during the present investigation was electrolytic powder shown in Fig. 3, and was chosen because of its particular adaptability to the work described in this Paper. The screen and chemical analyses of this powder are shown in Table I. In the preparation of compacts of high electrical conductivity, the purity of the copper powder is of importance in addition to other factors, such as density and the state of internal stresses. These variables were studied briefly by pressing a number of compacts to various pressed densities, sintering them for one hour in hydrogen at 975OC and repressing. The size of the finished compacts was 1/4, by % by 8 in. The time interval from the application to the termination of pressure was approximately 20 sec. Some of the compacts were annealed before testing. The results are listed in Figs. 4 to 8, inclusive. In Fig. 4 the curves of pressed density vs. compacting pressure, and sintered density versus compacting pressure show the typical direct relationship of pressure and density. Compacting pressures exceeding about 30 tons per sq. in. result fiequently in expansion during sintering for the type of powder used. Fig. 5 indicates that variations in the initial pressed density within the range of about 5 to 6 grams per c, c., affect only slightly the pressure required to obtain a

Jan 1, 1946

By Earl Bardwell

(Butte Meeting, August, 1913.) THE structural relations existing between cuprous oxide and copper were first systematically studied by Heyn1, who suggested that a study of the microstructure of refined copper might be substituted for the analytical methods in vogue for determining the oxygen content of copper coming .;from the refining furnace. Hofman, Green and Yerxa,2 in their paper A Laboratory Study of the Stages in the Refining of Copper, working along the lines suggested by Heyn, showed that a study off the microstructure could be made to yield a correct estimate of the oxygen content of the specimen of refined copper under examination. In order to determine the oxygen content of the specimen of refined copper under examination a photomicrograph was first made. From the relative areas of copper and eutectic, the percentage of cuprous oxide and the corresponding percentage of oxygen were then readily calculated. It was found that the values for oxygen thus obtained corresponded closely with the analytical results. With the idea of utilizing, this method of determining the oxygen content of each charge dipped from the refining furnaces at the Boston & Montana Reduction Plant, the physical testing laboratory was equipped with suitable apparatus for carrying out the work. It may be of interest to describe certain of the methods which have been worked out in, this connection and give such data as have been obtained bearing on the effect of the oxygen content of refined copper upon its conductivity.

Jan 7, 1913

By M. A. Schimmelpfennig, A. D. S. Gillies

Loss of visibility due to the occurrence of atmospheric fogging in underground mine airways can lead to longer travel times and loss of production efficiency, an increase in the frequency of vehicular and foot traffic accidents and difficulty in checking rock surfaces for instability and loose material. Where hot and humid surface air meets colder underground air, conditions for fog formation may be present. Further, suspended particulate matter from diesel exhausts or stoping operations together with slow movement of air along passageways may contribute to formation. This study describes an investigation being undertaken with the cooperation of Kennecott&apos;s Ozark Lead Co. to identify causes of the problem.

Jan 1, 1984

By W. T. lsbell

HERCULANEUM, MO., about thirty miles south of St. Louis on the Mississippi River, is the site of the lead smelter of the St. Joseph Lead Co. The lead concentrates come by rail from the Flat River district and from three properties in Madison County, Missouri; from the Balmat division in St. Lawrence County, New York; a small tonnage from the Tri-State district; and occasionally from the Aguilar property in Argentina. The average grade is 67 to 68 percent lead and 1 to 3 oz of silver. The bulk of the material is flotation concentrate, with some gravity or table concentrate. No secondary metals, outside drosses, or any materials high in bismuth, arsenic, or antimony are treated. All concentrate is received in box-caps and is unloaded directly from a trestle into the concentrate bins at the roaster plant. Flux, coke, and any miscellaneous lead-bearing material is either unloaded directly into bins or unloaded with a locomotive crane. All moving and switching of cars is done with two thirty-ton steam locomotives. Shipping facilities for the plant are provided by the Missouri-Illinois Railroad. Water for the plant and for fire protection is obtained from a dam built in a near-by creek. Drinking water both for plant and town is obtained from

Jan 1, 1947

By F. F. ESPIE

Giving the keynote address in the final session of a conference dealing with closely related topics has a disadvantage in that much of what can be said has been said. It also has an advantage, however, because it presents the speaker with the opportunity to integrate and analyse the material presented by the various speakers. I would like to look to the near future in Australia and the United States of America, to the risks, problem areas, and changes of a rapidly evolving post-industrial era-an era we are beginning to experience where industry no longer &apos;calls the tune&apos;. We miners have been quick to point out and emphasize, that ours is a &apos;high-risk&apos; industry in the world of business and commerce. Yet, clearly those who have survived, and been successful, have learned to anticipate and cope with risk and change. This ability has been a &apos;distinguishing feature of the industry&apos;s leaders who, in market studies and commodity selection, exploration and development, mine planning, metallurgical pro- cessing, and general administration and operation 1. identify areas-of risk or inevitable change, 2. analyse, test and quantify those factors of risk or change, and 3. design methods, systems, equipment to eliminate, moderate, or control or economically compensate for predicted risks or changes.

Jan 1, 1978

By S. H. Williston

IT not often that bore hole surveys can be checked by actual. civil engineering methods. A recent Arizona survey was checked by normal surveying methods and the comparison of the results should be of value to both oil and mining men. During the summer of 1948 the Phelps-Dodge Corporation, at its Copper Queen property near Bis-bee, Ariz., drilled a 1245 ft, 8 in. diarn, churn drillhole in a mineralized area and cased part of it, intending to use it to transfer mill tailings for stope fill. The hole, as frequently occurs, was not straight, and, in endeavoring to locate the bottom in the underground workings, they found no evidence of the hole at the underground coordinates directly below the surface location. The noise of the drilling tools was reasonably clear, but the direction of sound was uncertain. Preliminary tests with available equipment were not successful in locating the bottom of the hole. Because of the mineralized character of the area and the fact there was some casing in the hole, any magnetic method of well surveying would give results of doubtful value. Sperry-Sun gyroscopic well-surveying instruments were finally used to locate the bottom of the hole. These instruments consist of a gyroscope to determine azimuth and either a pendulum or bubble inclino-meter. A multiple shot camera photographs both instruments on a single film and superimposes the photograph of a watch. Coordination of depth with time at the surface makes it possible to select the corresponding picture for any depth. After making several runs of the empty instrument housing from the top of the hole to the bottom to make sure there were no obstructions in the hole, three surveys on wire line were completed during the afternoon. The three surveys, in which readings were taken at different points in the hole on each survey, were computed and gave the following locations of the bottom of the hole in relation to the surface collar: survey No. 1—24.92 N, 30.30 W; survey No. 2—24.24 N, 31.11 W; survey No. 3—26.54 N, 27.72 W. Then the data from the three surveys were combined into a single set of calculations which gave a location for the bottom of the hole: combined surveys—24.27 N, 30.16 W. (Fig. 1.) Immediately upon the determination of the coordinates at the bottom of the hole, a drift on the 1300 ft level was started toward the indicated loca- tion some 38 ft northwest of the coordinates of the surface location, The bottom of the hole was located within the drift round in which it was expected, and the transit survey run to the actual location of the hole indicated N 27.18, W 29.71. This shows a discrepancy between the well survey and the transit survey of 0.45 ft in the westerly direction and 2.91 ft in the northerly direction. All surveys, both gyroscopic and transit, fell well within the width of an ordinary drift. While this is satisfactory for almost any and all mining requirements, a theoretical examination was made as to reasons for the discrepancy. A study of the course of the hole indicates that considerable right turn or spiral existed, and in all probability the surveying instrument was pulled out of alignment while traversing the turn by approximately 0.05 ft at the top and another 0.05 ft in the opposite direction at the bottom of the instrument. If such an allowance were to be made, the survey calculations would almost exactly correspond with those determined by transit. This sort of discrepancy would be minimized by the use of stabilizing guides. It is unfortunate that physical laws probably effectively prevent the use of gyroscopic instruments in EX and AX diamond drill holes. The directive power of a gyroscope falls off inversely at some rate between the third power and the sixth power of the diameter. Present instruments can be run in casing 53/4 in. ID or over and might be adapted to somewhat smaller diameters, but the difficulty of reducing these diameters to 11/4 in. or 2 in. is almost insurmountable at the present time. Acknowledgment The author wishes to express his appreciation to the Phelps-Dodge Corporation for permission to publish this article, and to the Operating and Engineering Departments for their cooperation on the survey; also to Donald Hering, of the Sperry-Sun Well Surveying Co., who actually made the survey and calculated the results.

Jan 1, 1951

By S. H. Williston

IT not often that bore hole surveys can be checked by actual. civil engineering methods. A recent Arizona survey was checked by normal surveying methods and the comparison of the results should be of value to both oil and mining men. During the summer of 1948 the Phelps-Dodge Corporation, at its Copper Queen property near Bis-bee, Ariz., drilled a 1245 ft, 8 in. diarn, churn drillhole in a mineralized area and cased part of it, intending to use it to transfer mill tailings for stope fill. The hole, as frequently occurs, was not straight, and, in endeavoring to locate the bottom in the underground workings, they found no evidence of the hole at the underground coordinates directly below the surface location. The noise of the drilling tools was reasonably clear, but the direction of sound was uncertain. Preliminary tests with available equipment were not successful in locating the bottom of the hole. Because of the mineralized character of the area and the fact there was some casing in the hole, any magnetic method of well surveying would give results of doubtful value. Sperry-Sun gyroscopic well-surveying instruments were finally used to locate the bottom of the hole. These instruments consist of a gyroscope to determine azimuth and either a pendulum or bubble inclino-meter. A multiple shot camera photographs both instruments on a single film and superimposes the photograph of a watch. Coordination of depth with time at the surface makes it possible to select the corresponding picture for any depth. After making several runs of the empty instrument housing from the top of the hole to the bottom to make sure there were no obstructions in the hole, three surveys on wire line were completed during the afternoon. The three surveys, in which readings were taken at different points in the hole on each survey, were computed and gave the following locations of the bottom of the hole in relation to the surface collar: survey No. 1—24.92 N, 30.30 W; survey No. 2—24.24 N, 31.11 W; survey No. 3—26.54 N, 27.72 W. Then the data from the three surveys were combined into a single set of calculations which gave a location for the bottom of the hole: combined surveys—24.27 N, 30.16 W. (Fig. 1.) Immediately upon the determination of the coordinates at the bottom of the hole, a drift on the 1300 ft level was started toward the indicated loca- tion some 38 ft northwest of the coordinates of the surface location, The bottom of the hole was located within the drift round in which it was expected, and the transit survey run to the actual location of the hole indicated N 27.18, W 29.71. This shows a discrepancy between the well survey and the transit survey of 0.45 ft in the westerly direction and 2.91 ft in the northerly direction. All surveys, both gyroscopic and transit, fell well within the width of an ordinary drift. While this is satisfactory for almost any and all mining requirements, a theoretical examination was made as to reasons for the discrepancy. A study of the course of the hole indicates that considerable right turn or spiral existed, and in all probability the surveying instrument was pulled out of alignment while traversing the turn by approximately 0.05 ft at the top and another 0.05 ft in the opposite direction at the bottom of the instrument. If such an allowance were to be made, the survey calculations would almost exactly correspond with those determined by transit. This sort of discrepancy would be minimized by the use of stabilizing guides. It is unfortunate that physical laws probably effectively prevent the use of gyroscopic instruments in EX and AX diamond drill holes. The directive power of a gyroscope falls off inversely at some rate between the third power and the sixth power of the diameter. Present instruments can be run in casing 53/4 in. ID or over and might be adapted to somewhat smaller diameters, but the difficulty of reducing these diameters to 11/4 in. or 2 in. is almost insurmountable at the present time. Acknowledgment The author wishes to express his appreciation to the Phelps-Dodge Corporation for permission to publish this article, and to the Operating and Engineering Departments for their cooperation on the survey; also to Donald Hering, of the Sperry-Sun Well Surveying Co., who actually made the survey and calculated the results.

Jan 1, 1951