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By P. Shahinian, J. Weertman

Minimum creep rates of nickel samples were measured in the stress region of 2.5x107 to 2.8xl0 dyne per sq cm and the temperature region of 400° to 1100°C. The creep rate seems to be proportional to (stress) at stresses below 7x10H dyne per sq cm. The activation energy of creep is approximately 65,000 cal per mol. IN a recent theory' of steady-state creep which is based on Mott's dislocation climb mechanism, the following creep equation was derived for creep in polycrystalline metals (if where K is creep rate, Q the activation energy of self-diffusion, S the entropy of activation of self-diffusion, L' the grain size, L the subgrain size, b the length of the Burgers' vector of a dislocation, u the shear modulus, u the stress, a the critical shear stress, M the density of active Frank-Read sources, v the vibrational frequency of a vacancy, and kT has its usual meaning. This equation predicts a creep rate which depends on the stress through a power law at low stresses. At high stresses the creep rate increases much more rapidly with stress. The theory breaks down for stresses great enough that the inequality holds true. It was the purpose of the present in-

Jan 1, 1957

By Y. Topkaya, R. E. Johnson, D. Buttinelli, B. R. Palmer, A. Geveci, L. Stoppa, C. Lupi, F. Pochetti

Representative samples of a composite mixture of three typical Cu/Zn complex sulphide ores, namely Black-, Yellow- and Altered-ore, from the Cayeli deposit in Turkey, were used for leaching tests in 2.2 M FeCl3, or 1 M CuC12-2 M NaCl solution in the temperature range from 313 K to 363 K (40O to 90O C), with and without the presence of an organic solvent for elemental sulphur, such as CCl4. The leaching rates of copper and zinc were quite high, as expected, in FeCl3 solution and complete recovery of both metals was obtained at the highest temperature when the solvent was present. However in CuC1, solution, extraction yields of the order of 95% only for Cu and Zn were achieved and the positive effect of the solvent was not clearly shown. The kinetics curves of Cu leaching by FeCl3 indicated a model of reaction rate depending on the particle surface, as in a chemically controlled reaction, in tests with the presence of CCl4. Without the solvent, or in CuCl2 media, the model of the diffusion controlled reaction seemed to prevail. Values of apparent activation energy, in both of the leaching processes, were determined and compared with those reported in literature.

Jan 1, 1993

By LINDSAY BOTTOMER, Tassos Grammatikopoulos, Massoud Aghamirian, MARK FEDIKOW

A master composite (Master Comp) sample was prepared from three pegmatite zones from the Zoro Dyke D1 for mineralogical analysis and heavy liquid separation (HLS). The mineralogical examination was conducted on a subsample that was crushed to approximately P80 = 600 μm. The sample consists of spodumene (10.5 percent), quartz (29.3 percent), plagioclase (29.0 percent), K-feldspars (21.3 percent), micas (5.1 percent), tourmaline (2.9 percent) and Fe-Mn-phosphates (0.1 percent). Liberation of spodumene (88 percent) and gangue minerals, including quartz (89 percent), feldspars (94 percent) and micas (83 percent), is very good at this P80 . The average lithium (Li) concentration is 3.7 percent in spodumene, 2,196 ppm in micas, 1,001 ppm in tourmaline and 115 ppm in K-feldspars. Spodumene accounts for 96 percent of the total Li in the sample. The mineralogical data indicate the potential to recover spodumene by flotation with minimal Li losses due to other Li carriers. The HLS was conducted on a subsample that was crushed to smaller than 6.4 mm, with the smaller than 600 µm fraction removed from this test. The HLS results indicate it is possible to produce a high-grade lithium concentrate, with close to 6 percent Li2O, after the rejection of iron silicates with magnetic separation.

By A Hilli, K Kosmara, J Steyn

PT Nusa Halmahera Minerals (PT NHM) is an Indonesian joint venture company owned by Newcrest Mining Limited (75 per cent) and PT Aneka Tambang (Persero) (25 per cent). PT NHM operates two underground gold mines, Kencana and Toguraci at the Gosowong mine site in North Halmahera District, North Maluku Province, Indonesia.On 8 February 2016, a major ground movement occurred in the K-Link orebody of the Kencana underground mine, effectively blocking the only two access ways to the stoping area. Following mine clearance, it was found that a Solo production drill rig operator, who had been drilling in the Level 10 Extraction Drive was still underground, cut off from the rest of the mine by the ground movement.Communication, nutritional and logistic supply to the trapped operator was established with the breakthrough of two diamond drill holes. A range of technical expertise and opinions from both on and off-site were sought and two options were chosen for implementation of the rescue operation. The rescue was completed successfully on 16 February 2016 with the operator being rescued in good physical and mental health.CITATION:Kosmara, K, Hilli, A and Steyn, J, 2017. Eight days entrapped – PT Nusa Halmahera Mineral’s rescue of a trapped miner, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 155–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By J. E. Murphy

A method is being developed by the Federal Bureau of Mines for recovering lead metal from galena without the generation of SO2. Lead chloride is obtained by leaching lead concentrate at a temperature of approximately 100° C with FeCl3 solution: PbS + 2FeCl. " PbC1 2 + 2FeC1 2 + S. Electrolysis of the PbCI 2 product in a fused-salt bath results in deposition of molten lead metal at the cathode and evolution of chlorine at the anode. The chlorine can then be absorbed in the spent leach solution to regenerate FeCl3 for recycling. Optimum electrolyte composition was a PbC12-LiCl eutectic containing 7.6 wt-pct LiCl. The PbCl2-NaCl eutectic also proved satisfactory. Electrolysis in the PbCl2-LiCl bath at 450° C yielded 99 pct current efficiency at a current density of 5 amp/in2 with an energy requirement of only 0.24 kW-hr/lb metal produced. This compares with 98 pct current effi¬ciency and 0.26 kW-hr/lb metal produced for the PbCI2-NaCI bath. A typical lead deposit contained less than 100 ppm total detectable metallic impurities. At the low temperature employed for electrolysis, there was essentially no vaporization of Pb or FbC12.

Jan 1, 1974

Lower Silesia Coal Basin/SW Poland/ is adjacent to highly gas saturated igneous massiv and since the beginning of this century more than 1500 outbursts have occurred in four existing mines, including 1295 in the most hazardous mine Nowa Ruda. Prevailing part of these are carbon dioxide/coal outbursts of ejected masses 50-5000 tonnes/av.200/t and gas volume released from 200 m3 to 800,000 m3 Magnitude of these phenomena is growing with the depth and for present extraction levels/ 375-753 m/ may be expressed by a formula: M = 4.25/H-400/, where M-masses ejected, t and H - depth of extraction, m. Regulations obligatory hitherto call for gas pressure measurements to be made in 3 m long and 42 mm dia. boreholes spaces not more than 25 m along the longwall face and taking sample of drillings for desorption testing. Criteria of a hazard are following: pressure higher than 30 kPa /for C02/ or 80 kPa /for CH4/ and desorption more than 1,44 cm3/g. These criteria are not satisfactory because many outbursts occurred in spite of low values of parameters measured and for several times no hazard was evident after very high values were obtained. Moreover, observations show that a huge majority of case outbursts occurred in coal weakened by local geological distortion.

Jan 1, 1980

By P. Somasundaran, K. P. Ananthapadmanabhan

A knowledge of the role of effects and interactions of chemical species is important in developing an understanding of the behavior of mixed minerals and natural ores in beneficiation processes such as flotation and flocculation. In this study the role of such species was examined for the calcite-apatite system by conducting flotation of each mineral in various supernatants prepared by mixing with water. Supernatants of apatite and even that of calcite depressed the flotation of calcite markedly in the pH range of 5 to 13. Addition of Ca(NO3)2, K2C03, and K3P04 also produced definite effects under various pH conditions. Apatite flotation was also affected by the mineral supernatants and by carbonate and phosphate solutions. The results are analyzed in terms of the surfactant's solubility properties and the mineral's electrochemical and dissolution properties. While depression of calcite flotation by the dissolved species is found to be governed by depletion of oleate by bulk precipitation, the depression of apatite flotation is caused by the carbonate and phosphate species in the system. Turbidity measurements and a thermodynamic analysis of possible interactions in the system support these considerations. The effect of the supernatant of minerals on their own flotation suggests the important role of kinetics of various surface interactions in comparison to that of mineral dissolution.

Jan 1, 1985

(Members are urged to send in for this column any notes of interest; concerning themselves or their fellow-members.) Members and guests who called at Institute headquarters during the period Nov. .10, 19 16 to Dec. 1.0, 1916: Chester Atkinson, La Fundicion, Peru. , Paul Llewellyn, East Chicago, Ind. F. J. Brule, Toronto, Ont., Canada. Harry March, London, England. Sterling H. Bunnell, New York, N. Y. E. P. Mathewson, Toronto, Ont., Canada. G. H. Cunningham, Hobart, Tasmania.' E. W. Moore, Budapest, Rumania. Courtenay DeKalb, Tucson, Ariz. W. J. Pentland, Guadalajara, Mex., E. H. Dickenson, New Y.. Heinrich Ries, Ithaca, N. Y. E. B. Durham, Mount Kisco, N. Y. W. E. Saunders, Philadelphia, Pa. L. B. Eames, Pueblo. Colo. J. G. Scrugham, Reno, Nev. N: H. Emmons, 2d, Copperhill, Tens. - W. H, Seagrave, Kennecott, .Alaska. R. E. Hoffman, Hannibal Mo.'s H. B. Small, Magangue, Colombia. B. B. Hood, Chronic, N. J. W. H. Staver, Washington, D. C. H. E. Jackman, Rochester, N. Y. R. K. Stockwell, Santiago, Chile. F. H. Jackson, Joplin, Mo. Warren D. Thompson, Boston, Mass. Knight S. Jordan, Provo. Utah. Thor Warner, Kingman, Ariz. William Kelly, Vulcan, Mich. S. T. Wellman, Cleveland, Ohio. W. H. Lanagan, San Francisco. Cal. F. H. Willcox, Pittsburgh, Pa. H. H. Lauer, Northampton, Pa. Arthur K. Adams has been appointed geologist to the Andes Copper Co.

Jan 1, 1917

By M. Xian, M. Jahazi, Y. L. Lin

The 2-mm butt joints of ZE41A-T5 sand castings were laser welded at different defocusing distances on two surface conditions (as-cast or machined) using a continuous wave 4 kW Nd:YAG laser system at a power of 2.5 kW and a welding speed of 6.0 m/min. Two welding modes (conduction or keyhole) have been observed. The adjustment of defocusing distance can greatly influence the establishment of conduction or keyhole modes. On the machined surface conditions conduction welding is obtained at a power density of 4.0 x 105 W/cm2. In contrast, keyhole welding is reached at a threshold irradiance of 1.5 x 106 W/cm2. Neither conduction nor stable keyhole modes have been established at a range of power density from 7.7 x 105 to 1.2 x 106 W/cm2 on the machined surface conditions. On the as-cast surface conditions keyhole is obtained at a power density as low as 4.0 x 105 W/cm2 but good surface quality is obtained at a defocusing of +2 mm. The as-cast surfaces require lower power irradiance for the formation of keyholes indicating that they have higher energy absorptivity for Nd:YAG laser beams probably due to coarse surface morphology.

Jan 1, 2004

The following is am incomplete list of members and guests who called at Institute headquarters during the period May 10, 1918 to June 10, 1918. Arthur K. Adams, Potrerillos, Chile. J. M. Mahoney, Wilkinsburg, Pa. John Carter Anderson, Tucson, Ariz. Benjamin L. Miller, South Bethlehem, Pa. George S. Blair, Camp Cordon, Ga. Wilbur A. Nelson, Nashville, Tenn. W. A. Deane, Summitville, N. Y. Miles G. Nixon, Chicago, Ill. Charles H. Fulton, Cleveland, Ohio. Walter G. Perkins, San Francisco, Cal. Rudolf Gahl, Inspiration, Ariz. G. M. Ponton, Ottawa, Canada. C. C. Griggs, Eureka, Utah. D. A. Powell, Columbus, Ohio. J. F. Hanst, Potrerillos, Chile. H. W. Reed, Salt Lake City, Utah. Stanley C. Herold, Pittsburgh, Pa. J. C. L. J. Seelig, Padong, East. Indies. Floyd D. James, Boston, Mass. Oberlin Smith, Bridgeton, N. J. Charles Janin, San Francisco, Cal. Harrison Souder, Cornwall, Pa. E. Horton Jones, Copper Cliff, Ont. Stanley A. Spellmeyer, Camp Meade, Md. William Kelly, Vulcan, Mich. Roger S. Sperry, Waterbury, Conn. Ichiro Kitsunezaki, Tokyo, Japan. D. R. Thomas, Toronto, Canada. P. K. Lucke, San Antonio, Tex. Thor Warner, Phoenix, Ariz. E. Francis McCrossin, Birmingham, Ala. L. Douglass Anderson, formerly superintendent of the United States Smelting Co., Midvale, Utah, is now manager of smelters, Intermountain District, United States Smelting, Refining & Mining Co., Salt Lake City, Utah.

Jan 7, 1918

By J. O. Marsden

Over the past decade, the copper industry has been through an extended downturn followed by several years of sustained high copper price. A number of new technologies have been developed over the past 10 years aimed at reducing costs by decreasing energy, labor, and materials requirements, or by increasing metal recovery. The energy intensity of different copper extraction routes and different technologies varies considerably and this has a significant impact on the economics of extraction. Based on average ore grade materials, the total energy for the extraction of copper typically varies from about 24-26 MJ/lb (6.7-7.2 kWh/lb) for the mining, crushing, milling, flotation, smelting and refining route to about 14¬16 MJ/lb (3.9-4.5 kWh/lb) for the mining, crushing, heap leaching, solution extraction and electrowinning route. New technology developments are providing opportunities for significant reductions in energy consumption for copper extraction, representing energy savings up to 20-25% in some cases. In addition, in many cases, these new technologies have introduced environmental, safety and health benefits over the incumbent technology. Some of these technology developments have been more successful than others, and many hold great promise for application in the coming decade. This paper provides an overview of the technology developments that have occurred, and explores the underlying reasons behind successful implementation.

Jan 1, 2007

By José Carlos A. Cintra

This paper addresses a new experimental procedure to measure the shaft friction and the base resistance of bored piles during static load tests. It is proposed that a set of polystyrene foam discs, placed between the shaft and the base of the pile, be used instead of the usual instrumentation. Throughout the initial stages of the loading test, the foam discs will allow only the mobilization of the shaft friction. The load x settlement curve clearly shows that the shaft friction vanishes at low settlement values. As the load test proceeds, the base resistance is also mobilized. This procedure was used in two belled piles bored at the Experimental Foundation Field of the University of São Paulo, at São Carlos, Brazil. Both piles were 8 m long and had a shaft diameter of 0.6 m. The enlarged base had a diameter of 1.5 m and a height of 0.9 m. Twenty foam discs with a thickness of 20 mm each were placed between the enlarged base and the shaft of the pile. The load tests indicated ultimate shaft frictions of 28 and 30 kPa for measured settlements of 8.98 and 7.39 mm. Base resistance values at failure were 617 and 499 kPa, for a chosen settlement of 10% of the pile base diameter. The proposed approach seems to be straightforward, efficient and inexpensive.

Jan 1, 2002

Participating Scholarship Colleges and Universities 134 AmerCable, Inc 144 Andalex Resources, Inc 118 ARCO Coal Company 148 Behre Dolbear & Company, Inc 101 Coastal States Energy Company 100 Commercial Testing & Engineering Company 88 Crane & Hoist Sales Inc 121 Cyprus Amax Minerals Company 115 Dakota Coal Company DriltechInc 135 Empire Machinery Company 94 Energy West Mining Company 122 GH Hensley Industries 126. 127 Hitachi Construction Machinery (America) Corp. 12 Ingersoll-Rand Company 141 Jennmar Corporation 142 Joy Mining Machinery - A Harnischfeger Industries Company 104 K & P Sales Engineers, Inc 114 Kennametal Inc 95 Kennecott Energy Company 133 Kerr-McGee Coal Corporation 96 LeTourneau, Inc 145 Long-Airdox Company 112 Magnum Metals, Inc 138 McLanahan Corporation 129 Mine Technik America 124 Morrison Knudsen Corporation 97 National Mining Association 98 Nielsons,Inc 136 The North American Coal Corporation 130 Northwestern Resources Company 125 O&K Orenstein & Koppel, Inc 14 Peabody Western Coal Co 131 Phillips Machine Service, Inc. 13 Pincock Allen & Holt 120 Powder River Coal Company 107 Ramsey Technology, Inc 119 Rust Tractor Company 90 Salt River Project 91 Savage Industries Inc 89 Sheraton Steamboat Resort and Conference Center 111 Stamler Corporation (An Oldenburg Group Company) 117 Tamarron Hilton Resort 137 TerraMatrix Inc 139 TIC (The Industrial Company of Wyoming, Inc.) 99 Trapper Mining Inc 106 Wagner Equipment Company 116 Western Energy Company 105 Wheeler Machinery Company 128

Jan 1, 1996

By Horace Pops, L. L. Isaacs

SOLID-STATE transformations at low temperatures are frequently studied by optical metallography. Greninger and ooradian' and Hull and Gar-wood2 have examined the martensitic-type transformations in 0-phase Cu-Zn alloys during continuous cooling below room temperature. The lowest range of temperatures in the apparatus described by these investigators is limited to approximately 110°K. Present studies of reversible first-order phase transitions near liquid-helium temperatures have necessitated the design of a new cold-stage cryo-stat for optical metallography. The features of interest of this instrument are as follows: a) temperatures down to 4.Z°K are obtainable; b) the specimen is always under vacuum, thereby avoiding the condensation of moisture; c) specimens can be rapidly cooled or heated at varying rates, thus permitting studies of transformation hysteresis. Fig. 1 shows the details of the cryostat. All major parts are made of type 304 stainless steel. Both helium and nitrogen cans are Heliarc-welded to the helium filling tube, permitting the use of a common shielding can. Hence, the over-all weight and the area of the evacuated surface are mini- mized. The copper sample holder is screwed into the bottom of the helium can. To assure good thermal contact between the sample holder and the refrigerant, an indium ribbon is placed on the threads

Jan 1, 1964

By Anupam Saxena

This paper presents a case history of design, prediction, probe and production pile driving monitoring, loading test, and installation of piles for a 22-story condominium tower in southwest Florida, U.S.A. ASC was commissioned to provide value engineering services in the proper selection of an economical and satisfactory foundation system. For the site-specific subsoil conditions, various types of foundations were considered and following an evaluation of high structural loads, site-specific constraints, and the production timeframe mandated by the project owner, a prestressed concrete pile-supported system was selected as an economical and effective foundation approach. The building foundations were designed for a compression capacity of 575 kN (65 tons) for the tower and 220 kN (25 tons) for the parking structure. The axial pile capacity and lengths were predicted using SPT91 software. The validation of these capacities was derived from driving 21 probe piles and performing static loading tests on selected probe piles (2 in compression and 1 in tension). The predicted pile capacities were evaluated with results from static loading tests on selected probe piles. This information was effectively utilized as part of an overall quality control program to install a total of over 920 prestressed concrete piles to lengths ranging from 11.5 to 16.5 m (37 to 54 ft) below existing ground elevation as part of the foundation support system.

Jan 1, 1996

By B. J. I. Adair, K. R. Weller

The bulk scavenger tailing from Aberfoyle's Hellyer Concentrator, which represents about one-third of the total tailing, runs about 2.5-3 g/t gold and 140-200 g/f silver. Both values are very finely disseminated, particularly the gold. Aberfoyle wished to establish whether ultra-fine grinding followed directly by cyanide leaching could be applied to the tailing for recovery of gold and silver. The work comprised the determination of gold and silver recoveries as a function of grind size and leaching time, the specific energy consumption required for continuous wet grinding of the tailing to the specified product size in a small horizontal continuous stirred mill, and an estimate of the rate of media consumption. The maximum extraction of gold, 23.3% was obtained from the finest product, with the highest cyanide concentration and longest leach time, confirming earlier work. A similar result was obtained for silver. The specific energy requirement for milling rose from 27.7 kWh/t for a P80 of 8.1 um to 219 kWh/t for a Pea of 2.3 um. The consumption of ceramic media was about 1.6 g/kg of final product. An extensive QEM'SEM Trace Mineral Search on the unground tailing failed to identify any gold-bearing particles but did identify silver-bearing particles which displayed a variety of textural associations and liberation characteristics.

Jan 1, 1998

By Blom MS

Two well-developed styles of mineralization occur in the Nevados del Famatina mining district, Famatina ranges, La Rioja province, Argentina. Porphyry molybdenum- copper-gold mineralization and high level acid sulphate alteration/mineralization (Nevados del Famatina) are related to intrusion of the Pliocene Mogote rhyodacite porphyry complex. High sulphidation epithermal mineralization (La Mejicana) is developed peripheral to the Nevados del Famatina deposit. Both are hosted mainly by the Ordovician Negro Peinado metapelites.At Nevados del Famatina, five mineralized fracture events have been identified and correlated with four distinct alteration assemblages. Stage I (barren quartz) and stage II (molybdenite¦sphalerite¦pyrite) mineralization are associated with a K-silicate alteration assemblage of K-feldspar+biotite+quartz+magneti te¦ilmenite¦anhydrite. Stage III (bornite+pyrite+sphalerite+molybdenite ¦chalcopyrite¦idaite) and stage IV (chalcopyrite+pyrite +sphalerite+gold¦tennantite-tetrahedrite) mineralization are related to a quartz-sericite assemblage of quartz +phengite+illite+pyrite+rutile. Stage V mineralization is divided into two substages. Stage Va (chalcopyrite +pyrite+sphalerite¦ tennantite-tetrahedrite ¦ tellurides ¦ gold ¦enargite¦famatinite¦stibnite¦molybdenite) is related to a sericite-clay assemblage of quartz+illite+kaolinite ¦montmorillonite¦alunite. Alunite-kaolinite alteration (alunite+pyrophyllite+kaolinite+ aluminum - phosphate -sulphate minerals ¦illite¦fluorite¦corundum¦anhydrite) occurs in the upper part of Nevados del Famatina associated with the later stage Vb (quartz+famatinite +chalcopyrite+covellite + chalcocite ¦ marcasite ¦ enargite ¦ luzonite¦sphalerite¦melnikovite) mineralization.

Jan 1, 1990

By V. Steinbach

Non-renewable mineral raw materials are grouped into three categories to investigate ways leading to sustainable use of natural resources: 1.) metallic resources, 2.) non-metallic resources with the exception of the fertilizer minerals, and 3) the fertilizer minerals for the nutrients nitrogen (N), potassium (K), and phosphorous (P). With the exception of minerals in Group 3 which are essential for plant growth, mankind does not need raw materials as such, only the intrinsic property of a material that fulfils a useful function. This is especially true for non-metallic materials. Metallic resources have the best chance to become renewable if one makes optimal use of the resources of the man-made technosphere. For the fertilizer elements K and N there does not exist a problem, because sea water or air respectively provide an inexhaustible source for them. This does not apply to P however. So P is serving as one of our apposite case studies for solving sustainability challenges. For all the challenges along the road from a non-sustainable to a sustainable resource economy technology can be envisioned to come to the rescue provided conditions that are considered to be essential for sustainable use for all natural resources-- affordable renewable energy and human ingenuity to find new solutions for functions, to optimize processes and to minimize losses-- are satisfied.

Jan 1, 2011

By David Davison

Metafex®* is an inert material that is more energetic than explosives when activated. Because Metafex is inert until activated (a moment before use), it can profoundly change the logistics of systems and processes that require energetic materials. We have obtained positive test results for a Metafex configuration (called a flat pack) that operates at the practical voltage of ~20 kV. We describe the outcome of the testing and potential uses of the material.

Jan 1, 2006

The Bureau of Mines evaluated short-delay coal mine detonators manu-factured by three domestic companies for electrostatic sensitivity, strength, and no-fire current level. Electrostatic sensitivity was studied in pin-to-pin and pin-to-case modes employing lO-kV potential. Strength of detonation was measured in the Bureau's underwater test fa-cility. No-fire current was measured using a constant-current power supply unit. Test procedures and experimental data are included.

Jan 1, 1985