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By Galen H. Clevenger, MARTINUS H. CARON

Although there are exceptions, oxidized silver ores containing the higher oxides of manganese are generally refractory to hydrometallurgical methods of treatment. When these ores are of high enough grade they can be smelted; indeed, some rather low-grade ores of this type have been smelted at a profit because of their fluxing value. In the past, when these ores could not be smelted, they either were not treated or were treated at low efficiency, generally by cyanidation. The need for thorough investigation of the problem was therefore evident for some time before the writers began their research. The problem of treating manganese-silver ores seems to have been recognized first about 35 years ago by C. W. Goodale in applying pan amalgamation at Tombstone, Ariz. He attributed the low extraction of silver to the fouling of the mercury by manganese rather than to the presence of a refractory compound of manganese and·silver. Although definite knowledge as to the cause of the poor extraction of silver was lacking, a more or less effective preliminary treatment, that is, a chloridizing roast, was applied. E. M. Hamilton, in 1909, was perhaps the first to define clearly the problem as it affects the cyanidation of silver ores and to suggest possible methods of preliminary treatment. Most of the work done in the interval between the appearance of Hamilton's paper and the assumption of the investigation by the authors was in the nature of routine tests covering suggestions already made rather than of research directed to a fundamental study of the problem. No practical application has so far been made of any of these proposed processes. The investigation described in this bulletin has proved that there s a refractory compound of manganese and silver-probably a manganite- insoluble in cyanide solution and other common solvents for silver. Although this compound has not been isolated from natural ores, it has been made synthetically, and shows all the characteristics of the natural product. Furthermore the authors have shown definitely that heating in air a relatively small amount of a silver compound with a large excess of silica (in the proportions ordinarily occurring in a commercial silver ore) renders

Jan 1, 1925

The November General Meeting of the Branch was held in the St. Helena Club at 8.00 p.m. on the 17th November, 1970. Mr J. N. Saunders (Chairman) was in the chair. There were also present six fellows, N. A. Honnet, C. J. Isaac, J. G. Kirchner, (Committee Members), J. M. Meyer, S. L. S. Swart and J. W. Wilson; seven members, D. V. Baum, M. de Lange, A. H. Edwards, G. J. G. Emere, E. R. Penny, G. P. Rundle, C. G. J. Vermeulen; six graduates, N. Mayer, H. Miller, E. J. Shillaber, P. J. H. Short, M. H. Smith, T. R. Stromsoe; five associates, M. Andriesse, A. E. Hooper, A. Paschalides, R. L. Solms, W. M. Todd; one student, J. C. Simms and 14 visitors. Apologies for absence were received from Messrs L. O. W. Leimer and G. Y. Nisbet. MINUTES OF THE ANNUAL GENERALMEETING The Minutes of the Annual General Meeting held on the 27th August, 1970, were taken as read. Their adoption, which was proposed by Mr N. A. Honnet and seconded by Mr J. G. Kirchner, was carried unanimously. MINUTES OF THE JULY GENERALMEETING The minutes of the General Meeting held on the 8th July, 1970, were taken as read. Their adoption, which was proposed by Mr C. J. Isaac and seconded by Mr J. G. Kirchner, was carried unanimously. GENERAL BUSINESS Members were advised that no more applications could be entertained for the visit to Western Holdings; they could, however, still apply to visit Welkom Mine and Harmony. TALK The Chairman invited Mr A. Paschalides to deliver his talk on 'Controlled blasting in stopes and new explosives developments'. The presentation proved to be of great interest to the meeting and lively discussion followed the talk. Mr N. A. Honnet proposed a vote of thanks to Mr Paschalides on behalf of all members of the O.F.S. Branch. CLOSURE The Chairman thanked Mr Paschalides for his talk and all present for their attendance, and as this was the last meeting for 1970 he wished all members a Merry Christmas and a Happy New Year. He declared the meeting closed at 9.30 p.m.

By Douglas Talley

This report describes a 4-inch diameter borehole probe which contains a low light level TV camera, magnetic compass, light illumination source, bottom/water detector sensor and a pointing angle sensor. The camera viewing angle is at a right angle to the probe's body. All data from the sensor is multiplexed into the closed circuit camera video for transmission on a single 50 ohm coaxial cable to a surface control unit. Likewise control of the probe's power, zoom lens, focus, panning and aperture is accomplished via a down-link multiplexed on the same cable.

Jan 1, 1984

By B. D. Pandey, D. Bagchi, Premchand

During the separation and recovery of metals from the ammoniacal leach liquor of Indian Ocean nodules by solvent extraction-electrowinning (SX-EW) in close-loop operation, the copper electrolyte containing ~40g/L Cu, 20 g/L Ni and 180 g/L sulphuric acid is bled-off to control the impurities. The recovery of copper and nickel as powders has been examined from the copper bleed solution following partial decopperisation, crystallization of mixed sulphate of the two metals and aqueous hydrogen reduction. From the dissolved sulphate solution containing 17.68 g/L Cu, 18.83 g/L Ni and 0.03 g/L Fe, the copper powder was precipitated at initial hydrogen pressure of 26 bar in an autoclave in 90 min at 140 °C. The residual copper from the spent solution was removed as sulphide and nickel powder was then recovered (99%) in two stages from a solution of pH 4.5 at 40 bar pressure and 190 °C. However, 98% nickel recovery in one stage was achieved when hydrogen reduction was carried out from an ammoniacal solution in the pH range 9-11. Copper and nickel powders were produced from the bleed solution with acceptable purity and specifications suitable for P/M applications.

Jan 1, 2004

By E. Lifshin, R. E. Hanneman

QUANTITATIVE applications of the electron micro-beam probe frequently involve the evaluation of complex mathematical expressions and/or the analysis of large amounts of experimental data. The purpose of this communication is to describe briefly a versatile and useful computer program system that is applicable to analyze rapidly a wide variety of practical microprobe problems. This system consists of a group of ten FORTRAN programs that can be stored on tape, cards, or in the memory disc of the computer. These programs, or links, can be run individually or in any prespecified sequence without interrupting the operation of the computer or without destroying information which is being transfered from one link to another. For the program system described here a GE-235 computer with disc storage was used, so that the DCHAIN method of program linking was employed. Included in the library are programs to: 1) initiate analysis of a new set of data and transfer control between all other programs in any predetermined manner; 2) generate theoretical calibration curves of composition vs relative intensity; 3) generate empirical deviation parameters from least-square fits of experimental calibration data from standards of known composition; 4) convert raw X-ray data to corrected composition; 5) determine inter diffusion coefficients by Matano analysis of con centrat ion -distance data on a uniaxial diffusion couple; 6) determine activation energies and frequency factors of temperature-activated processes such as diffusion; and 7) generate calibration curves for determination of the thickness of thin films using microanalysis. A detailed description of these computer programs and their underlying principles is available on request from the authors."' The first program to generate theoretical calibration curves of corrected relative intensities vs composition uses the Poole and Thomas atomic number correction' and the Philibert absorption factor' with a voltage-dependent mass absorption coefficient for electrons in the alloy. A modified Castaing fluores- cence correction is also used which includes the effects of both Ka and KO radiation and over voltage.' Once the theoretical curves have been calculated in 1 wt pct intervals, these results are least-squares fit to obtain Ziebold deviation parameters' which are stored in COMMON in the computer memory. The net discrepancies between the original theoretical calibration curve and the regenerated curve using the Ziebold parameter are computed. Although this link is explicitly written for K-K fluorescent interactions, it can be applied to K-L, L-K, and L-L interactions as previously disc~ssed."~ Similar programs have also been written to utilize the Wittry fluorescence correction, Birks combined corrections, and various other corrections.' These modified programs have proved to be quite useful for quantitative comparisons of the results of the various theories. The program for conversion of raw X-ray data to corrected composition includes corrections for drift, backround, and instrumental dead time. The corrected intensities are converted to composition by use of the Ziebold equation"2 and parameter obtained from the program system. The results can be obtained for either atom or weight fractions. In addition to accurately computing interdiffusion coefficients the Matano analysis program calculates least-square smoothed values of concentration, concentration gradient, and curvature for each point on the raw input concentration profile. In order to obtain high accuracies a unique method of performing a least-square polynomial fit to incrementally advancing profile segments which overlap is used.' This program has been successfully modified for use in ternary diffusion problems3 and can readily be modified to handle analysis of diffusion profiles which include phase boundary discontinuities. This link is generally applicable to analysis of interdiffusion data obtained by other techniques as well as by the microprobe. The primary function of the next program is to least-squares fit experimental diffusion data to the normal Arrhenius function: D = Doexp(-Q/RT), to obtain values of Do and Q. In addition the probable error and one, two, and three u statistical confidence limits of DO, Q, and log D are evaluated. This program is also directly useful for analysis of any other simple temperature-activated processes including conductivity, and certain deformation and chemical processes. The program to generate calibration curves for film-thickness determination using the microprobe is based on a numerical integration of the equation derived by Cockett and ~avis.' Values of film thickness obtained by this program for copper on various substrates are in good agreement with measurements made by other techniques. Versions of the above program system have been prepared for use with or without a remote teletype connection to the computer for processing on either a real-time or time-share basis. The instrumentation coupling a microprobe to a teletype for automatic data collection and analysis by the presently described program system has been reported elsewhere by the authors.' If teletype equipment is not used to communicate with the computer, standard methods of card reading and tape reading can be used. In either

Jan 1, 1967

By Adrian L. Moodie

Austar Coal Mine (formerly Southlands and Ellalong Collieries) has had a long association with difficult strata control conditions associated with mining depth and a highly jointed/cleated coal seam. The conditions include poor longwall face conditions, cyclic loading, heavy tailgate (TG) roadway conditions, and difficulties in maintaining stable roadways on development at 5.2 m (17 ft), as well as the geotechnical challenges of an 8.5-m (27.9 ft) -wide roadway required for installation faces. The introduction of Longwall Top Coal Caving (LTCC) to this environment has aided in the management of some of these issues, but LTCC has also given rise to other geotechnical considerations. Additional geotechnical issues associated with LTCC not only require management during operations, but also require consideration when evaluating new mining areas at Austar Coal Mine or potential LTCC extractable resources throughout Australia and the world. In September 2006, LTCC commenced at Austar Coal Mine in longwall panel A1. Since this point the LTCC face has been increased from 147 to 216 m (482 to 709 ft)and finally to 227 m (745 ft) in width, and it has also been rehanded and modified in the three fully extracted panels to date. The application of LTCC in panels A1, A2, A3, and now A4 has been very successful, both from a coal resource recovery point of view and in the management of the principal hazards of spontaneous combustion and strata control. This paper focuses on the geotechnical aspects of the application of LTCC at Austar Coal Mine and also reviews some advances in general strata control management at the mine.

Jan 1, 2011

By Andrew Allan

During recent years underground production for the Pennsylvania anthracite region has reached the lowest output per man per day figure of the last decade and a half. This fact, combined with increased unit costs for labor and material, has forced the market price of anthracite ever higher. Over the years the mines have become deeper, and haulage distances have increased, thus adding to the mining costs. The industry now recognizes the need for new mining techniques to offset increasing costs. The Federal Bureau of Mines, through its Anthracite Research Laboratory, is engaged in a program of underground-mining research in cooperation with anthracite-producing companies to aid in reestablishing the economy of the region by introducing methods and/ or machines that will reduce underground-mining costs and, at the same time, enhance the safety of the workmen.

Jan 1, 1953

By R. L. Beatty

Bond International Gold's Colosseum gold mine was discovered in 1865. No recorded production occurred, however, until the 1930s, with production of about 19 kg (615 oz) of gold. The mine was closed in 1942 as a nonessential industry during World War II. The property was acquired by Dallhold Resources in mid-1986. Construction of a 1.1-million Mt (1.2-million st), carbon-in-pulp (CIP), cyanide mill began in November 1986 and was completed in September 1987. Minable reserves are estimated to be 9.5 Mt (10.5 million st), with an average grade of 2.1 g/t (0.061 oz per st). This article describes the general process flow and plant equipment. And it looks at the maintenance and operational problems encountered in the first six months of operation. Process description Ore is direct hauled from the open-pit mine 1.5 km (1 mile) to the crushing facility. There it is crushed to -152 mm (-6 in.) with a single- stage, 1.5-m x 1.2-m (60-in. x 48-in.), 186.5-kW (250-hp), Fuller-Traylor jaw crusher. The ore is then stockpiled in a 31.7-kt (35,000-st) reclaim ore pile. Lime is added to the crushed product as it is conveyed to a single 6.4-m x 4-m (21-ft x 13-ft), Hardinge semiautogenous grinding (SAG) mill, followed by a single 4.3-m x 7.3-m (14-ft x 24-ft) Hardinge overflow ball mill. After grinding, the slurry is thickened and then preaereated for three hours. Following preaereation, the pulp is leached with NaCN at a pH of 11, also for three hours. The slurry then goes through a seven-stage CIP circuit for 21 hours. Then the tailings slurry is preaereated for three hours before cyanide destruction using the Inco process. Loaded carbon is eluted using an Anglo American strip, followed by electrowinning on stainless steel wire. The stainless steel wire is transferred to refinery cells where the gold and silver is plated on stainless steel plates. Following electrore-fining, the gold-silver foil is removed, melted, and poured into dore bars for shipment. The crushing, milling, refining, and maintenance processes require 37 people. Crushing The crushing area required changes and modifications following start-up. Several areas are of specific note. Structural failures Rubber support cushion blocks located under the coarse ore bin failed. These were replaced with heavier, more durable blocks and have since appeared to be satisfactory. A severe structural vibration was encountered in the entire crushing facility. A mechanical engineer, brought in by the contractor, determined the structure needed more support and cross-bracing.

Jan 1, 1989

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''. 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's investment; -the lessor evaluates his risk in terms of the underlying value of the assets;

Jan 1, 1985

By GEORGE S. POPE

The Government of the United States annually expends approximately $8,000,000 for coal. Prior to 1906, this coal was purchased mainly on its reputation, or trade name, rather than under contracts specifying the heating value of the coal, its contents of ash and moisture, and other characteristics. In recent years the Government and other large consumers have appreciated more and more the desirability of definitely determining by chemical analyses and tests the character and quality of coal deliveries. Studies of engineroom and boiler-room efficiencies and economies point forcibly to the necessity of devoting more thought to the improvement of the boiler-room end. This calls for an intimate knowledge of the character and quality of the fuel used. The analyses and tests of delivered coal furnish such data, whereby the power-plant results can be comprehensively studied and a continuous check maintained on the coal and on the conditions of plant operation. Under authority of acts of Congress making appropriations for analyzing and testing fuels belonging to or for the use of the United States Government, a laboratory is maintained at the headquarters of the Bureau of Mines, 'Washington, D. C., where samples representing deliveries of coal purchased for Government use are analyzed and tested. The Bureau of Mines has been active in promoting the purchase of coal by the Government under specifications,a that is, by contracts that make definite requirements regarding the heating value of the coal expressed in British thermal units, and the composition as shown by proximate analysis. Under many of these specification contracts the bidders guarantee the quality of the coal offered, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled and analyzed to determine whether the coal is of the quality guaranteed by the contractor, and if it is not, the price to be paid is decreased in proportion; but if the coal is of higher quality, the price is proportionately increased. The analyses of coals or the guaranties offered by the bidders may in some cases be used for determining the award of a contract, but if the coals offered are of widely different characteristics, it may be difficult to determine which would prove the cheapest fuel, without having their relative evaporative efficiencies. Hence, it may be necessary to conduct evaporative tests under service conditions in order to determine which coal is particularly adapted for successful and economical use in the plant. But once a particular coal is selected, regardless of the procedure of determining the award of a contract, then the greatest advantage of the specification method is realized, in that it guarantees to the purchaser coal of uniform character and quality, thereby insuring the best results in the plant. The cost of purchases, under such specifications, of fueL for the use of the Government now aggregates approximately $4,100,000 per annum, and the cost of additional fuel for which samples are taken and submitted to the Bureau of Mines for analysis in order to determine the character and quality of the coal furnished aggregates some $3,000,000 per annum more. In fact, information is now obtained regarding the quality of fuel purchased on almost all contracts large enough to warrant sampling and analysis and heatingvalue tests. It may be said that the purchase of coal under specification is still in the stage of evolution and development, and that experience and time will be required to develop fully standard specifications and methods of sampling and analysis that may be used universally. The success of the specification method for the purchase of coal and the reliability of analysis now rests almost entirely on sampling.a Improper sampling leads to controversies, with resulting condemnation of the specification method in general and the value of laboratory analyses and tests in particular. A number of bulletins b have been published showing the results of the purchase of coal by the Government under specifications. This bulletin is a compilation of the results of coal analyses by the Government, including those made in the fiscal years 1908-1910, which have been previously published, and later analyses representing coals analyzed during the fiscal years 1911-1915. The preceding bulletins gave individual analyses or average monthly analyses, whereas this bulletin gives the average analyses only for the entire contract. It is hoped that this compilation of a series of comparable analyses of the coals purchased by the Government will be of value alike to coal dealers, to Government engineers, to purchasing agents, and to all users of coal.

Jan 1, 1916

By Peter G. Groer

The commonly used exact methods (1-2) to determine the WL measure the total a activity or the total number of a counts during three preselected time periods. Due to the half-lives involved (TRaB = 26.8 min, TRaC = 19.7) I these methods take 3S minutes to complete the a activity Ra measurements. Methods using the total a counts, obtained at times less than about one RaB half-life after the end of sampling run into statistical 214 problems. These methods are almost blind to RaB (Pb214) as a consequence of its relatively long half period (see above) and the fact that RaB is a ß emitter. The way out of this dilema is to measure RaB directly through its ß activity. Since RaB's daughter Rae (Bi214) is also a ß emitter, the two f3 spectra have to be separated to obtain RaB alone. How this is accomplished 1s described in subsequent sections describing the theory of the IWLM and its calibration. 2.0 THEORY The IWLM samples air for two minutes and counts this airs ample for two minutes starting 3 sec after the end of the sampling period. The instrument has three channels. The lower a channel, the upper a channel, and one ß channel. The total RaA counts observed are accumulated in the lower a channel, the total RaC? counts are stored in the upper a channel. The total ß counts from RaB and RaC are recorded in the ß channel. These three quantities are functions of NA, NB, and NC, the unknown concentrations

Jan 1, 1975

By Richard L. Ash

Introduction The blasting capabilities of commercial explosives are often rated according to their loading densities and detonation velocities. Both the density and velocity are relatively easily measured, the values of which can be used for determining the approximate detonation pressure developed by an explosive during any given set of blasting conditions (1-5). Knowledge of the actual rate of detonation attained at all points along a charger's length also is considered to give a good indication of how well the explosive is functioning. Many factors affect the density and velocity and have been thoroughly discussed by various authors (4, 6-12). For recording velocities several methods are available, but the resistance-wire, or probe, continuously recording technique has the distinct advantage of providing a record of the complete progress of an explosive reaction from the time it first initiates. Figure 1 is a copy of a typical record obtained by the procedure with certain significant information indicated. The theory and applications of the method are extensively covered in the literature so need not be reviewed for this report (13-18). Only the specific equipment and procedure employed for this investigation are presented.

Jan 1, 1973

By D. Eastick, S. Hardcastle

"Over the last few years, a multi-faceted feasibility study has been evaluating the introduction of hydrogen fuel cell-powered equipment into underground mines to replaced diesel engine-powered equipment. The analysis has shown that under normal operating conditions fuel cells could at the very least be an environmental and health benefit by eliminating combustion engines and their unwanted by-products. However, they could also generate significant reductions in the amount of ventilation a mine needs to supply when compared to dieselized operations; this would further decrease a mine’s energy consumption, its associated greenhouse gas impact, and also reduce a mine’s significant ventilation-associated costs. Fuel cell-powered equipment also has the advantage of lower noise and heat production compared to its equivalent diesel-powered counterpart.The degree to which fuel cells can generate ventilation benefits in underground mines depends upon a number of operational parameters and mine specific qualifiers such as current ventilation control or management, mine depth, inherent dust conditions, and minimum velocity requirements.However, another major consideration in the introduction of fuel cells in underground mines will be the safety requirements associated with diluting and removing the potentially explosive hydrogen in the event of a gas leak. In outside surface applications, it is possible to use dispersion, buoyancy, time, and lack of ignition sources as mitigating factors in deriving a low risk of an explosion. However, in underground operations, these factors change, and dispersion and buoyancy are limited; time may not be available and, in non-coal mines, ignition sources are not typically controlled. When a hydrogen leak occurs, the availability of sufficient ventilation to dilute and effectively remove the gas will be critical. Consequently, ventilation may be the prime risk controlling factor. In this paper, the authors evaluate the potential benefits of replacing diesel engines with fuel cells in powered production equipment, discuss the mitigating qualifiers that could limit ventilation savings, and evaluate solutions to retain and maintain an additional ventilation capacity in the event of an emergency situation, such as a hydrogen leak from the fuel cell stack or its distribution system."

Jan 1, 2007

By J. A. Herdlick

Under authority of the Strategic Materials Act of June 1939, the Federal Bureau of Mines, in cooperation with the Geological Survey, began a broad program of investigation of the strategically important chromite deposits in Sweetgrass, Stillwater, and Carbon Counties, Mont. Extensive occurrences of chromite along the Stillwater Complex in Stillwater County were investigated. The two principal deposits, The Mouat-Sampson and Benbow mines, ultimately were developed and placed in production by the Federal Government. As a part of this general development program, the Carbon County chromite deposits near Red Lodge were examined by Bureau of Mines engineers in 1940, and by the Geological Survey .1-1 1942. The district was examined earlier by Schafer, and the Four Chromes area is mentioned briefly by Westgate. Although the Red Ledge deposits were considered to be of minor importance as compared to those of the Stillwater Complex, several of the ore bodies were adaptable to open-pit mining' methods, and one large deposit on Line Creek Plateau was readily accessible to the Red Lodge-Cooke highway. In 1941, the U. 3. Vanadium Corp. began mining crude lump-chrome ore from the deposit on Line Creek Plateau to supplement national stockpiles, which were being depleted by the rearmament program and the disruption of chrome-ore imports by the European war. Access roads gore constricted to Hellroaring Plateau, and the mining operations were extended to that area. A gravity concentrator with a capacity of 200 tons per day was built and operated at Red Lodge to beneficiate lower-grade ore from the district.

Jan 1, 1948

Council and Standing Committees - 1981/82 President: G. Y. Nisbet. Senior Vice-President: Prof. A. N. Brown. Junior Vice-President: Prof. R. P. King. Honorary Treasurer: Prof. D. G. Krige. Immediate Past President: Dr P. R. Joehens. Members of Council: B. C. Alberts, J. D. Austin, P. T. Fewell, C. E. Fivaz, J. J. Geldenhuys, Dr A. K. Haines, P. N. Harris, H. E. James, C. G. Knobbs, Dr B. K. Love¬day, Dr J. Lurie, C. S. MacPhail, D. G. Malan, J. C. Mostert, G. C. Thompson, Dr H. Wagner. Chairman, Witbank/Middelburg Branch: B. Rohrmann. Chairman, Orange Free State/Klerksdorp Branch: K. F. W. Eick. Chairman, Materials Engineering Specialist Division: G. Pienaar. Past Presidents serving on Council: Dr M. G. Atmore, H. Britten, Prof. D. D. Howat, Dr J. P. Hugo, D. G. Maxwell, Prof. R. P. Plewman, Dr R. E. Robinson, Prof. M. D. G. Salamon, P. W. J. van Rensburg, D. A. Viljoen, P. A. von Wielligh. Standing Committee Chairmen: Constitution, Rules and Policy, Dr P. R. Jochens; Membership, Prof. R. P. King; Training, Career Guidance and Education, P. A. von Wielligh; Journal, Prof. A. N. Brown; Monograph Series, D. G. Malan; Technical Programme - Metallurgy, C. E. Fivaz; Technical Programme - Mining, P. N. Harris; SAIMM Schools - Metallurgy, Dr B. K. Loveday; SAIMM Schools - Mining, J. D. Austin; 1982 CMMI Congress, Dr M. G. Atmore; Awards, Dr P. R. Jochens; Adjudication, Dr P. R. Joehens; Phoenix National Committee, Dr M. G. Atmore; Excursions, J. C. Mostert; Mines and Works, Prof. A. N. Brown; World Mining Congress - National Committee, Prof. R. P. Plewman.

Jan 1, 1982

By Jerry E. Olson

In 1984, the U.S. Bureau of Mines conducted a mineral survey of the Pahute Peak Wilderness Study Area (WSA) (NV-020-621), which covers 57,529 acres in Humboldt County, NV. About 90 percent of the WSA is underlain by Tertiary volcanic and shallow intrusive rocks. Of the remainder, metasedimentary rocks of unknown age are in contact with Cretaceous intrusive rocks in the northwest corner of the WSA. The entire WSA is within an upthrown fault block of the Basin and Range physiographic province. Portions of the WSA, especially south of Pahute Peak (Big Mountain), may be part of an eroded caldera structure. No mines or evidence of major exploration were identified within the WSA. Workings in Copper Canyon, claim blocks along the northwest boundary, and zones of anomalous character as defined by the Bureau of Land Management were examined. No mineral resources were identified, but sample results indicate three significantly mineralized sites, one with indications for zinc skarns in Copppr Canyon, another favorable for precious metals 2 miles south of Copper Canyon, and another area near the northwest boundary with geologic conditions characteristic of molybdenum deposits. Further investigation of these sites is warranted. Petrified wood is present in small amounts near the west central range front.

Jan 1, 1986

By Hal W. Hunt

Heavier loading and more efficient equipment is helping to keep driven piles competitive in America. Better Knowledge and testing of soils and support materials make it practical to use higher stresses; this is being strongly promoted by those directly concerned with timber, steel and concrete piles. Readily available point protection is increasingly used to assure penetration of piles without damage to full load bearing capability. Fabric drains are being installed with pile equipment to speed consolidation of soils. Sheet pile configuration has changed; production has been reduced largely because of imports. Dynamic checking of representative piles for load carrying capability is replacing conventional load testing of just a pile or two ? at much lower cost.

Jan 1, 1987

Large quantities of combustible materials are often found in underground metal and nonmetal mines, with support timber most often the predominant combustible material. Oils, lubricants, paper, cartons, and rags are additional combustible materials and are commonly found in maintenance shop areas. Welding and cuting, shorted or overloaded electrical cables, spontaneous combustion, and careless smoking are some of the common fire ignition sources. Inexpensive, reliable fire detection and suppression systems are available to provide early warning of such fires and to isolate and extinguish fires that originate in underground maintenance shop areas. Technology developed and demonstrated under Bureau of Mines Contract H024216, Mine Shaft Fire and Smoke Protection System, may be applied to protect underground maintenance shop areas. The mine area described in this report is a representative ex-ample only; the fire protection system described considers costs, benefits, equipment performance and includes the concepts of: ? Early warning and alarm ? Isolation ? Extinguishment ? Control. Each fire protection system application requires analysis of numerous variables including total mine profile (depth, personnel, escape routes, hazards, etc.).

Jan 1, 2011

By Franklin M. Grynkewicz

As part of the Boston Harbor clean up project, the new 1,000 mgd Deer Island Sewerage treatment plant includes ten 240 feet high egg-shaped "residuals" tanks. Contract documents called for these structures to be supported on 2,600 sixteen inch concrete filled pipe piles. The project site is underlain by highly variable glacial and marine deposits. Subsurface conditions vary from one extreme where firm glacial deposits exist at subgrade to the other extreme where 70 feet of medium stiff clays overlying weathered bedrock must be dealt with. The most common profile consisted of 15-20 feet of sands, 20-40 feet of marine clays, and 20-60 feet of stratified glacial deposits (commonly called tills) overlying Argillitic bedrock. Post bid redesign work, initiated as a cooperative effort between the owner and the general contractor, demonstrated that an $8 million savings could be realized if high capacity 48 inch diameter caissons replaced the specified pipe piles. A highly unusual arrangement of having the general contractor and specialty subcontractor providing input to the owner's engineering team allowed the redesign work to proceed on a "fast-track" schedule.

Jan 1, 1992

By V L. Los, G J. Abramson

The paper examines three types of polar zoning of ore-forming and associated elements that can be detected from geochemical data. Polar zoning is mapped in the form of geochemical ore systems of various ranks. Various types of polar zoning can be found in some systems, which present a general geochemical model of the ore object. The genetic basis of zoning is examined from the perspective of the conception of geoelectrochemical redistribution of matter, including ore-forming elements. The volume of the geochemical ore system may be used in the prognosis of resources for every rank.

Jan 1, 1999