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By R. C. Gifkins, A. Gittins

A. Gittins and R. C. Gifkins (University of Mel-houvne)— Evidence from somewhat similar experiments to those described in this paper has led us to the conclusion that possibility 2) of the four listed on p. 319 is a description of what happens in grain boundary sliding. That is, sliding is limited by accommodation deformation, it being necessary to the Continuance of sliding that this accommodation should take place. An example of such accommodation, though probably not the most important, is fold formation at triple points. The evidence and arguments for this point of view are set out in Refs. 14 to 16. In particular, an experiment with a lead bicrys-tall5 seems to support point 2) rather than 3). In creep of this specimen it was found that at least 90 pct of the extension of a zone 0.3 mm wide at the boundary was supplied by sliding at the boundary. The sliding was localized in a region at the boundary very much smaller than 0.3 mm, in fact, in a region too narrow to resolve optically. In poly crystalline Specimens&apos; there appears to be a surface effect, as found by Rachinger," but it appears that this may not manifest itself at low strains. "Low strains" means <10 pct for a Pb-TI alloy, <2.5 pct for magnesium or "Magnox" A12 alloy, or <40 pct for a 0 brass. Up to this extension the sliding, measured by the mean vertical step at boundaries, is proportional to extension. We are able to say this with some confidence, since the error bars on our points are statistically derived. Our results would lead us to think that the error bars on other work, including that of Mullendore and Grant, are much too large at low strains to show this

Jan 1, 1963

By E. Horton Jones

CONTENTS I Page Introduction ....:......................... 3 Chapter I. Unit Costs. . ...................... 4 Chapter II. Comparative Costs ..................... 20 Chapter III. Composite Costs..................... 32 Chapter IV. Wage Scale....................... 36 Chapter V. Raw Material Prices................. 37 Chapter VI. Description oF Costs ................... 64 Introduction We have endeavored in the following "sheets" to give the unit construction costs derived from &apos;the building of the Arizona Copper Co.&apos;s new smelter, Clifton, Ariz., starting in February, 1912, and completing February, 1914.l In Chapter I—Unit Costs—are to be found the most elementary total unit costs which the accounts provide for. They are usable in the Clifton district. Here too are found the percentages to be added to an estimate for Engineering and General Expense. In Chapter II—Comparative Costs—these elementary costs have been classified, averaged and reported as labor and material unit costs. In such form the labor unit costs, when properly applied to similar conditions as these under which they were derived, are usable anywhere. The material unit costs are better disregarded for more accurate estimates and replaced by a newly priced bill of material. In Chapter III Composite Costs are given. They are unit costs built up from several elementary units, and likewise units of larger dimensions and simpler application, valuable for

Jan 1, 1915

By C. E. Shoenfelt

The year 1939 witnessed the rapid development of several of the more important Rocky Mountain oil and gas areas and the discovery of new oil and gas fields. As a further result of an active year, many oil fields had their productive limits greatly extended or responded to deeper drilling with oil production in lower horizons. In Colorado there was a substantial increase in refinery capacity, with three new units constructed. Its contribution to the crude-oil supply was an important extension of the producing area of a Western Slope field and a deeper oil-producing horizon in an old field east of the Front Range. Occurrences of gas were reported in two wells in northwestern Colorado, but severe winter weather prevented tests and the value of these discoveries cannot be determined at this time. Montana&apos;s northern fields were extended and a number of record wells were completed. The North Cut Bank area gives promise of wide expansion in 1940. The gas-producing area of Wyoming&apos;s Elk Basin field was extended into Montana on the north plunge of the anticline. The most important developments in Wyoming oil fields in 1939 were extensions to the producing area of Lance Creek and the discovery of a deeper pay in the Tensleep formation at Wertz dome. A new gas field at Horn Valley in the south central part of the state was the only new field discovered, but wildcatting was at low ebb in Wyoming in 1939. Colorado In Colorado, the year 1939 saw the completion of several interesting tests, but largely with negative results. Oil was discovered, however, in a deeper sand in the old Fort Collins field and the productive area of the Wilson Creek field was extended. Gas had been noted in two Western Slope wells, at Yellowjacket-Buford and at Trull, but their volumes had not been determined at the end of the year. Of principal interest, however, were the failures, descriptions of which will be given presently. One of these established a new depth record for Colorado.

Jan 1, 1940

By C. E. Shoenfelt

The year 1939 witnessed the rapid development of several of the more important Rocky Mountain oil and gas areas and the discovery of new oil and gas fields. As a further result of an active year, many oil fields had their productive limits greatly extended or responded to deeper drilling with oil production in lower horizons. In Colorado there was a substantial increase in refinery capacity, with three new units constructed. Its contribution to the crude-oil supply was an important extension of the producing area of a Western Slope field and a deeper oil-producing horizon in an old field east of the Front Range. Occurrences of gas were reported in two wells in northwestern Colorado, but severe winter weather prevented tests and the value of these discoveries cannot be determined at this time. Montana&apos;s northern fields were extended and a number of record wells were completed. The North Cut Bank area gives promise of wide expansion in 1940. The gas-producing area of Wyoming&apos;s Elk Basin field was extended into Montana on the north plunge of the anticline. The most important developments in Wyoming oil fields in 1939 were extensions to the producing area of Lance Creek and the discovery of a deeper pay in the Tensleep formation at Wertz dome. A new gas field at Horn Valley in the south central part of the state was the only new field discovered, but wildcatting was at low ebb in Wyoming in 1939. Colorado In Colorado, the year 1939 saw the completion of several interesting tests, but largely with negative results. Oil was discovered, however, in a deeper sand in the old Fort Collins field and the productive area of the Wilson Creek field was extended. Gas had been noted in two Western Slope wells, at Yellowjacket-Buford and at Trull, but their volumes had not been determined at the end of the year. Of principal interest, however, were the failures, descriptions of which will be given presently. One of these established a new depth record for Colorado.

Jan 1, 1940

By John J. Collins

Page Purpose and scope..................... 521 Core sampling......................... 521 Sludge sampling....................... 527 Combining core and sludge assays ...... 533 Deviation and surveying of drill holes. . . . 537 Conclusions........................... 544 Acknowledgments...................... 545 Bibliography.......................... 545 Purpose and Scope The purpose of this paper is to review a few of the problems involved in the interpretation of diamond-drill core and sludge samples, with the hope that it will stimulate discussion and bring forth some of the information on the subject that has been accumulated by various organizations. The release of these data would benefit the mining industry as a whole. Particularly valuable would be the details of drilling programs that have been tested by actual mining operations, as most of the available published material is unsupported by production records. The scope of this paper is limited to a few of the commonest problems of interpreting diamond-drill core and sludge samples and the deviation of holes. It does not include the description of routine operations performed by the drillers, nor the estimation of ore reserves. The methods of calculating reserves have been described,25,26,31,32,50,65 but more informa- tion is needed on the results shown by actual mining operations. Core Sampling The accuracy of diamond-drill-hole Sampling depends in large measure on the percentage of core recovery. As a general rule, the longer the run, the poorer is the recovery. Although the longer runs allow cheaper drilling costs, the determining factor should be the percentage of recovery desired. The problem is one of balancing accuracy against costs. Holes of larger diameter may show improved recovery, except as Joralemon* points out that there are some conditions in which small holes give better core recovery than large holes. This is particularly true, he says; in rocks like shattered quartzite, where larger core tends to break in angular fragments and grind up, while the diameter of smaller core is less than the distance between joint planes and grinding is not so serious. In a large measure the length of the sample run should depend on the type of deposit. Favorable drilling may allow uniform sample runs of 5 ft., 10 ft., or perhaps 20 ft. In veins or beds of relatively narrow widths and changing characteristics, however, the ore zone may be overrun and ground in a core barrel full of waste rock. Generally it is desirable to break the sample at a change in the rock or ore. Such a change; often indicated by a color change in the sludge water, should be a a for the driller to make a "dry" block and to pull out that run regardless of the length. Such a procedure permits the segregation of waste from ore samples so

Jan 1, 1946

By Leland H. Johnson

THE Tennessee Coal, Iron & Railroad Co.&apos;s ore mines began experimental tests with trackless mining units early in 1947. The units had many weaknesses to overcome, but are now well beyond the experimental stage and are becoming a necessity to ore seams that are amenable to this type of equipment. The development of this type of mining with the problems of increased underground supervision, maintenance, and training personnel, along with the benefits derived, are discussed.

Jan 12, 1950

By J. P. Nielsen, H. Margolin, E. Ence

The Ti-Ni phase diagram has been investigated up to 68 pct Ni with iodide titanium base alloys by metallographic, X-ray, and melting point methods, and from 68 to 90 pct Ni by examination of as-cast structures of sponge titanium base alloys. NVESTIGATION of the nickel-rich portion of the I Ti-Ni phase diagram was first reported by Vogel and Wallbaum in 1938.&apos; This work was subsequently extended to lower nickel contents by Wallbaum&apos; who indicated the possibility of a eutectic reaction for nickel contents below 38 pct. Long et al.3 studied the titanium-rich portion of the phase diagram and found eutectic and eutectoid reactions below 38 pct Ni. However, the temperature of the eutectic indicated by Long et al. was considerably lower than that suggested by Wallbaum. Long and his coworkers synthesized their alloys by powder metallurgical techniques and encountered oxygen and/or nitrogen contamination. Thus the diagram which was obtained did not represent binary alloying conditions. However from these results the features of the binary diagram were predicted. At Battelle Memorial Institute4 the Ti-Ni diagram was investigated up to approximately 11.5 pct Ni with sponge titanium alloys. The range of temperatures used was not sufficient to define the eutectoid temperature or composition. The data of Wallbaum2 and Long et al.8 were of particular interest for the present study, and although the work was originally concerned with the region below 40 pct Ni, the investigation was extended to higher nickel contents in an attempt to resolve the differences between these workers. Experimental Procedure Preliminary work on the Ti-Ni system was carried out with duPont Process A sponge titanium alloys to reduce the amount of subsequent work to be done with iodide titanium base alloys. The sponge titanium used contained 99.71 to 99.77 pct Ti, 0.1 pct Fe and 0.005 to 0.009 pct Ni. The iodide titanium obtained from the New Jersey Zinc Co. contained 99.9 to 99.95 pct Ti. Nickel used with sponge titanium was 98.9 pct pure. The high-purity nickel alloyed with iodide titanium was cobalt-free with approximately 0.05 pct C and was obtained through the courtesy of the International Nickel Co. The 15 g sponge titanium charges for melting were prepared by compacting in a die or by placing the weighed portions of nickel and titanium directly into the furnace. Iodide titanium charges were made by drilling holes in the as-received rod and inserting the nickel or by wrapping the nickel in sheet. Sponge titanium alloys containing from 0.2 to 90 pct Ni and iodide titanium alloys containing 0.2 to 68 pct Ni were prepared by these methods. In addition to these alloys several 1/2 1b sponge titanium alloys were supplied by the Allegheny Ludlum Co. The charges were melted in an arc furnace under an argon atmosphere. The procedures used were similar to those reported in the literature5,&apos; and the furnace has been described.&apos; Except for iodide titanium alloys with 40 to 68 pct Ni (see section on copper contamination), each alloy was melted for 1 min, then either turned over or broken before re-melting for an additional minute. Currents of 200 to 400 amp were used depending on the melting point of the alloy. Prior to heat treatment, alloys containing less than 14.5 pct Ni were hot-forged at 750°C. With the exception of alloys in the homogeneity range of the compound TiNi, alloys of higher nickel contents could not be hot-forged. Heat treatment of iodide titanium base alloys was carried out in argon-filled quartz capsules which were broken under water at the conclusion of heat treatment to quench the specimens. Temperatures were controlled to ±5oC and annealing times up to 48 hr were used. For melting point determination, specimens were placed in carbon crucibles which were in turn en-capsuled in argon-filled quartz capsules. The start of melting was determined by rounding of corners and by metallographic examination. Complete melting was considered to have occurred at that temperature at which the specimen assumed the shape of the crucible. Specimens were prepared for metallographic examination by mechanical polishing or by an electrolytic procedure." For alloys containing up to 80 pct Ni Remington A etch7 50 pct glycerine, 25 pct HNO,, 25 8 HF) was used. For higher nickel alloys aqua regia and Carapella&apos;s etch (5 g FeCl,, 2 ml HNO,, and 99 ml methyl alcohol) were employed. Specimens to be exposed for powder patterns were prepared by filing, by breaking specimens in a

Jan 1, 1954

Jan 2, 1966

By John R. Caldon

INTRODUCTION Leasing has become a major industry in many countries because of the advantages it affords. Whilst the accounting, legal and tax treatment of leasing varies from country to country, there is far more similarity than difference. The general approach to the subject is largely the same. This paper looks to the basic financial considerations in the decision to lease or buy. TYPES OF LEASES Before embarking upon the subject, it would seem appropriate to define a "lease". A lease may be defined as: "an agreement granting one party the right to use, for a specified period of time, property owned by another party in return for a series of payments of rental by the user to the owner&apos;&apos;. Ownership, of course, generally entitles the owner to unrestricted use of the asset over its useful life in contrast to a lease which gives the lessee use over a limited period. The distinction between the status of owner and a lessee often is fairly small. In this case we are dealing with what is generally termed a "finance lease". A finance lease is one which substantially transfers the risks and benefits of ownership from the legal owner to the lessee. For example, a finance lease would exist where the lessee enters into a lease of an asset for most of its useful life and has an option to buy the asset at the end of the lease for a price which takes cognisance of the rentals already paid. Where a lease does not substantially transfer the benefits and risks of ownership to the lessee, i.e. those benefits and risks remain with the owner and lessor, the lease is termed an "operating lease" and is an agreement for the renting and usage by the lessee of an asset owned by the lessor for a limited period. An example of an operating lease might be where a tenant leases a building for a defined period say 6 years with the rent and occupancy subject to renegotiation at the end of the lease term. The economic consequences of the distinction between a finance and an operating lease is very important. With a finance lease, the lessee has a de facto economic interest in the asset and the alternative to a finance lease is some form of purchase; with an operating lease, the lessee does not have a basic economic interest in the asset and consequently a comparison with a purchase option involves far more than simply a funding comparison. Some of the principal differences between finance and operating leases can be summarised as follows: (a) finance leases: -the risks and benefits of ownership are substantially transferred to the lessee; -the lessor normally recovers his investment during the term of the lease; -the lessor in entering into the transaction is relying more on the creditworthiness of the lessee than the underlying value of the asset; - the lease is either non-cancellable or a large penalty will apply for unilateral cancellation by the lessee; (b) operating leases -the risks and benefits of ownership remain essentially with the lessor; -the lease rental income would not normally cover the recovery of the lessor&apos;s investment; -the lessor evaluates his risk in terms of the underlying value of the assets;

Jan 1, 1985

ALABAMA Anniston.-Carrington, F. G. Auburn.-Brown, R. L. Bessemer.-Abbott, C. E. Dobbs, G. G. Ferguson, V. Salmon, H. S. Schaber, C. F. Birmingham.-Aldrich, T. H. Aldrich, T. H., Jr. Allen, A. W, Ball, E. M. Bonnyman, J. Bowron, J. Bush, M. W. Crawford G. G. Crockard, F. H. Ellis, E. E. Fairbairn, C. T. Gallacher, J. Geisiner, H. S.

Jan 1, 1917

By Warren H. Westphal

For mining and exploration, and indeed the entire mineral industry, the first century of AIME has ended with far more problems than it began. Paradoxically, most of these problems have arisen not because, the industry has been unsuccessful, but rather because it has succeeded too well. Whatever the public demand for minerals over the past 100 years, it has somehow been met-and met at a price well within the public&apos;s ability to pay for the products. But as AIME moves into its second century, the past successes of mining and exploration are beginning to levy a tax on the future. Prospectors have already found most of the rich and ready ores, and miners have dug them out. New mineral assets grow progressively harder to come by, and as they do, the need for them grows inversely more pressing. How and where and at what cost can adequate supplies be found? How and at what cost can they be mined from heretofore inaccessible recesses deep underground and under the seas-or from vast surface tonnages containing only minor values? And once they are found or won, how can these assets be husbanded for generations to come? How also can they be extracted without injury to the land, air and water on which we and our successors must depend? And what constructive use can be made of the incidental materials now treated merely as wastes-sometimes at great expense?

Jan 1, 1971

By Albert Ledoux

SEVERAL years ago my firm was representing the Mt. Lyell Co. of Australia, which was shipping its blister copper to a refining works in the United States. After the contract had been running for many months, the superintendent of these works discovered that if water was poured upon the surface of the bars much of it would disappear into the interior through blow holes. -Some experiments made by him showed that this could be a considerable amount, so that copper which had been rained on before it was weighed, although the surface appeared dry, nevertheless would contain water. It had frequently occurred in our experience-as samp-lers that the drillings from a lot taken by boring would come out quite wet, and in some cases, indeed, water would drip into the sample pan placed below the bars, due to the fact that the drill had penetrated a cavity or cavities containing water, which presumably got into the cavities at the time the copper was water-cooled after casting, there being, perhaps, no outlet to the surface. So far as I know, until this discovery at the refining works, no. one had thought that rain could penetrate into the interior of blister copper; at least in any quantity sufficient to be considered.

Jan 10, 1922

By Jerry Tien

Mine regulators are normally used for proper air distribution in underground mines. They are deliberately introduced resistance in the regulated airway, and by altering sizes, they can distribute specific air quantities to regulated splits and free splits (4, 5). The enactment of the Federal Coal Mine Health and Safety Act of 1969, the Federal Mine Safety and Health Amendments Act of 1977, and the regulations adopted by the Mining Enforcement and Safety Administration (now called the Mining Safety and Health ministration) prompted greater discussions of optimal mine regulator locations because of the Act&apos;s stringent ventilation requirements (2, 3). For example, by requiring the separation of the air used in the belt haulage entries from the intake and return airways, the regulations required the creation of a third type of airway---the neutral airway, as opposed to the intake and return airways, adding to the complexity of a mine&apos;s ventilation network. It is the intent of this report to show that panel regulators should be located in intake airways at the neck of a panel for a blowing fan system and in return airways at the neck of a panel for an exhausting fan system in order to achieve optimal air control. A computer simulation model is used to determine optimal mine regulator location.

Jan 1, 1983

By C. H. Samans, G. F. Tisinai, J. K. Stanley

The addition of nitrogen (0.10 to 0.20 pct) to Fe-Cr-Ni alloys of simulated commercial purity results in a real displacement of the u phase boundaries to higher chromium contents. The effect is small for the (Y + s)? boundary, but is pronounced for the (y + a +s)/(y + a) boundary. Although there is an indication of an exceptionally large shift of the n boundaries to higher chromium contents, especially in steels with nitrogen over 0.2 pct, the major portion of this apparent shift results from the fact that carbide and nitride precipitation cause "chromium impoverishment" of the matrices. The effect of combined additions of nitrogen and silicon to the Fe-Cr-Ni phase diagram is demonstrated also. Nitrogen can nullify the effect of about 1 pct Si in shifting the (y + o)/? phase boundary to lower values of chromium at all nickel levels from 8 to 20 pct. NItrogen can nullify this U-forming effect of about 2 pct Si at the 8 pct Ni level, but not at the 20 pct Ni level. The alloys studied were in both the cast and the wrought conditions. There are indications that the u phase forms more slowly in the cast alloys than in the wrought alloys if both are in the completely austenitic state. The presence of 6 ferrite in the cast alloys accelerates the formation of U. Cold working increases the rate of o formation in both cast and wrought alloys. THE major improvement in Fe-Cr-Ni austenitic alloys in recent years has been in the addition or removal of minor alloying elements to facilitate better control of corrosion resistance, sensitization, and heat resistance. One shortcoming of the austenitic Fe-Cr-Ni alloys, which never has been completely circumvented, is their propensity toward u formation. In the AISI-type 310 (25 pct Cr-20 pct Ni) and type 309 (25 pct Cr-12 pct Ni) steels, sufficient amounts of u phase can form, if service or treatment is in a suitable temperature range, to cause severe embrittlement. Also, there is a growing conviction that this phase may be contributory to some unexpected decreases in the corrosion resistance of certain of the 18 pct Cr-8 pct Ni-type steels. The present paper discusses the effect of nitrogen additions on the location of the (r+u)/d and the (y+a+u)/(y+a) phase boundaries in the ternary Fe-Cr-Ni system, for cast and wrought alloys of simulated commercial purity, and in similar alloys containing up to about 2.5 pct Si. The objective is to define compositional limits for alloys which will not be susceptible to u formation when used near 1200°F (650°C). An excellent review of the early studies of the u phase in the Fe-Cr-Ni system has been compiled by Foley.1 Rees, Burns, and Cook2 have determined a high purity phase diagram for the ternary system, whereas Nicholson, Samans, and Shortsleeve3 are- stricted themselves to a portion of the simulated commercial-purity phase diagram. Both groups of investigators show almost an identical position for the commercially significant (y+u)/y phase boundary. Further comparison of the work of the two groups indicates that, below the 8 pct Ni level, the commercial alloys have a decidedly greater propensity toward u formation than the high purity alloys. The two groups of workers agreed that both the AISI-type 310 (25 pct Cr-20 pct Ni) and the type 309 (25 pct Cr-12 pct Ni) steels are well within the (y+~) region and that the 18 pct Cr-8 pct Ni-type alloys straddle the U-forming phase boundaries. Nicholson et al.3 showed, in addition, that these boundaries shift toward lower chromium contents if greater than nominal amounts of silicon or molybdenum are added. The effect of nitrogen on the location of the s phase boundaries in the Fe-Cr-Ni system has not been known with any certainty. In 1942, an approach to this problem was made by Krainer and Leoville-Nowak,&apos; but at that time they apparently were unaware of the slow rate of s formation in strain-free samples and aged their samples for insufficient times, e.g., 100 hr at 650°C (1200°F) and 800°C (1470°F). For this reason, it would be expected that their (y+ u) /y boundary would be shifted toward lower chromium contents (restricted ?-field) when equilibrium conditions were approximated more closely. Procedure for Studying the Alloys The alloys used were prepared in the following way: Heats of 200 lb each were melted in an induction furnace. A 5 lb portion of each heat was poured into a ladle containing an aluminum slug for de-

Jan 1, 1955

By David S. Cahn

Pilot-plant and laboratory tests were made on blends of steel plant flue dust and portland cement to determine whether the flue dust could be pelletized for use as a source of iron in dry process cement manufacture. Strength and setting time results showed that an acceptable agglomerate can be made with a Type II portland cement binder. Abrasion-resistant and well-sized pellets were made in a horizontal drum, using a simulated closed circuit, with a binder content of 7.5% and a moisture content below 15%. Pellet quality was found to be relatively insensitive to changes in binder concentration above 5%. Simulations of stockpiling and weathering indicate that little difficulty would be encountered with use of the flue dust pellets in cement plants.

Jan 1, 1972

By Lauren A. Wright

SINCE the early nineteen-thirties the production of talc* in California has increased five-fold to a yield in 1947 of about 76,000 tons (fig. 1); conse- .&apos; Unless otherwise qualified, the term "talc" in this paper will imply a mixture of the pure talc with such related minerals as commonly occur in the commercial material. quently the state is now one of the nation&apos;s three principal talc producers. The 1947 output, which represented about one-sixth of the national total for that year, was approximately equal to production from Vermont, and was second in value to that from New York. New York has an annual output of about 130,000 tons. Three factors have been mainly responsible for the expansion of talc production in California. (1) Technical advances and innovations, particularly in the ceramic industry, have increased the demand for certain California talcs. The nation&apos;s high-qual- LAUREN A. WRIGHT, Junior Member AIME, is Associate Geologist, California Division of Mines, San Francisco, Calif. Los Angeles Meeting, October 1948. San Francisco Meeting, February 1949. TP 2622 H. Discussion of this paper (2 copies) may be sent to Transactions AIME before Feb. 28, 1950. Manuscripts received Dec. 7, 1948; revision received Aug. 29, 1949. This paper is Contribution No. 508 of the Division of Geological Sciences, California Institute of Technology, Pasadena, Calif. the industry, mainly through demand for the urgently needed steatite. Fibrous talc, used as a paint extender by the armed forces, also was produced in quantity. (3) Expanding western industry has continued to draw heavily on California talc deposits, and has extended the upward production trend into the postwar period. Considerably more than half of California&apos;s current talc output is used as ceramic raw material. The paint, rubber, paper, and textile industries are the more important consumers of the remainder. Smaller amounts are used as insecticide carriers, and in cosmetics, and various minor industrial applications. During World War I1 the principal steatite deposits were studied in detail by members of the U. S. Geological Survey; other sources of commercial talc in the state have in the past received but scant geologic attention. The following discussion is essentially a preliminary report based on research currently in progress by the California Division of Mines, and includes a brief outline of previous steatite studies by the U. S. Geological Survey. Distribution of California Talc Deposits: The principal talc resources of both California and Nevada are confined to an elongate belt that extends from the vicinity of Baker, in north-central San Bernardino County, northwestward to include the southern Death Valley region, the Inyo Range, and the Palmetto-Oasis district of western Nevada (fig. 2). This belt, of which all but the northernmost tip lies in California, is approximately 200 miles long and 30 miles in average width. Included in the belt are four contrasting areas. The deposits within each area are geologically similar and yield talcs that have characteristic properties and applications. Three of these local "talc provinces" lie within California&apos;s portion of the talc-

Jan 1, 1951

By Lauren A. Wright

SINCE the early nineteen-thirties the production of talc* in California has increased five-fold to a yield in 1947 of about 76,000 tons (fig. 1); conse- .&apos; Unless otherwise qualified, the term "talc" in this paper will imply a mixture of the pure talc with such related minerals as commonly occur in the commercial material. quently the state is now one of the nation&apos;s three principal talc producers. The 1947 output, which represented about one-sixth of the national total for that year, was approximately equal to production from Vermont, and was second in value to that from New York. New York has an annual output of about 130,000 tons. Three factors have been mainly responsible for the expansion of talc production in California. (1) Technical advances and innovations, particularly in the ceramic industry, have increased the demand for certain California talcs. The nation&apos;s high-qual- LAUREN A. WRIGHT, Junior Member AIME, is Associate Geologist, California Division of Mines, San Francisco, Calif. Los Angeles Meeting, October 1948. San Francisco Meeting, February 1949. TP 2622 H. Discussion of this paper (2 copies) may be sent to Transactions AIME before Feb. 28, 1950. Manuscripts received Dec. 7, 1948; revision received Aug. 29, 1949. This paper is Contribution No. 508 of the Division of Geological Sciences, California Institute of Technology, Pasadena, Calif. the industry, mainly through demand for the urgently needed steatite. Fibrous talc, used as a paint extender by the armed forces, also was produced in quantity. (3) Expanding western industry has continued to draw heavily on California talc deposits, and has extended the upward production trend into the postwar period. Considerably more than half of California&apos;s current talc output is used as ceramic raw material. The paint, rubber, paper, and textile industries are the more important consumers of the remainder. Smaller amounts are used as insecticide carriers, and in cosmetics, and various minor industrial applications. During World War I1 the principal steatite deposits were studied in detail by members of the U. S. Geological Survey; other sources of commercial talc in the state have in the past received but scant geologic attention. The following discussion is essentially a preliminary report based on research currently in progress by the California Division of Mines, and includes a brief outline of previous steatite studies by the U. S. Geological Survey. Distribution of California Talc Deposits: The principal talc resources of both California and Nevada are confined to an elongate belt that extends from the vicinity of Baker, in north-central San Bernardino County, northwestward to include the southern Death Valley region, the Inyo Range, and the Palmetto-Oasis district of western Nevada (fig. 2). This belt, of which all but the northernmost tip lies in California, is approximately 200 miles long and 30 miles in average width. Included in the belt are four contrasting areas. The deposits within each area are geologically similar and yield talcs that have characteristic properties and applications. Three of these local "talc provinces" lie within California&apos;s portion of the talc-

Jan 1, 1951

Large scale mining of Mesabi taconites may have moved nearer to realization with the arrival of the latest model Linde Jet-Piercing machine at Reserve Mining Co.&apos;s Babbitt, Minn. property. When the machine is placed in operation it is expected to pierce blast holes in the hard taconite beds up to 10 times faster than is possible with existing drilling equipment. The new primary blast hole drilling machine has been designated the JPM-3, and is the successor to the JPM-1, in operation at Erie Mining Co.&apos;s taconite mines at Aurora, Minn. The size of primary blast holes which can now be pierced has increased from a nominal 61 in. diameter to 71 in. diameter and maximum hole depth has increased from 35 ft to 47 ft. Development has progressed to where 71/2 in. holes can be pierced with the same speed as 61/2 in. holes. Piercing progress is controlled by electronic blowpipe descent controls. Other features of the JPM-3 include: automatic burner ignition from the operating cab; heated and air conditioned operating cab designed for all-year operation; mechanical improvements for sub-zero operation common to the Mesabi, and redesign of wearing parts for longer service with minimum maintenance. The 40-ton machine is self-propelled. Power, oxygen, and cooling water lines trail from the machine. Jet piercing is based on combustion products of oxygen and a liquid fuel such as kerosene. The flame, jetting from a burner at speeds of about 6000 ft per sec, disintegrates layers of spallable rock. The burner is cooled by water which is then directed through orifices around the periphery of the burner. The water changes to steam and carries the spallings out of the hole. The equipment used in Jet-Piercing is essentially a tractor-mounted blowpipe containing a combustion chamber and nozzle, which is in effect a miniature rocket motor, from which the supersonic combustion gases emerge to do their work.

Jan 1, 1952

By D. A. J. Swinkels

The problem of determining oxygen levels in liquid steel to aid in deoxidation control has received general attention for a number of years. Work in this direction started at the B.H.P. Central Research Laboratories early in 1967 with an evaluation of sampling techniques followed by vacuum fusion analysis to determine the oxygen content of the samples (1). It was found that these techniques had a number of drawbacks if they were to be used for deoxidation control. The method of analysis was rather too slow to allow effective control and measured total oxygen level rather than dissolved oxygen. Furthermore, the results were found to be very variable due to slag entrainment in the samples. Attention therefore turned to the galvanic cell method using a solid oxygen ion conductive electrolyte such as cubic stabilised zirconia. The ionic conductivity properties of electrolytes such as (ZrO2) 85 (CaO).15 had been studied by a number of investigators and had already been applied to the measurement of oxygen activity in gases, in lower melting metals such as copper, lead, tin, silver, alkali metals and indeed the first studies in steel had been made (2,3). Since then the results of a number of studies in the development of an expendable oxygen probe for steel have been reported (4-9).

Jan 1, 1972

"The Washoe Smelter is situated about two miles east of the City of Anaconda. The smelter site includes about 240 acres and peculiarly adapts itself in topography to the efficient handling of material. By reason of its being on a hill side it is possible to make the level of delivery of the product of one building the level of the charge floor of the next succeeding one.THE ORES: The ore treated comes principally from the Butte district and is hauled by the Butte, Anaconda & Pacific railway, a distance of twenty-eight miles, in trains of fifty 50-ton bottom-dump cars to the railroad yards at East Anaconda. At this point these trains are• split up according to their destination,—that is, as to whether they go to the concentrator and sampling mill ore bins, or to the storage bins. In each case they are made up into trains of eight or sixteen cars, according to the size of engine to be used, and are carefully weighed before delivery to their respective bills.Some idea of the magnitude of the works may be obtained from the following figures:Amount of ore that can be treated in 24 hours…12,000 tonsLime rock from adjacent quarries…2,300 tonsCoke used…500 tonsCoal for reverberatory use…500 tonsCoal for power use…50 tonsWater, per minute, 35,000 gallons.Men employed in and around Anaconda, 3,000. Monthly payroll for above, $300,000.00."

Jan 1, 1913