Search Documents

By Jinwu Kang

The hydraulic turbine blade of the matensitic stainless steel (Cr13%,Ni5%,Mo1%) is a kind of large and curved shape, which is susceptible to deformation in both casting and heat treatment processes. The coupling analysis of heat transfer, phase transformation and stress in heat treatment process of the turbine blade for Three Gorges Project is carried out by using Deform-3D software. Its temperature fields, phase fields and stress fields in heat treatment process are obtained. And its deformation is predicted. In the cooling process of normalizing, the blade exhibits relatively large deformation. Based on the stress analysis and deformation prediction in heat treatment process, an algorithm for the determination of reverse deformation of the blade casting in heat treatment process is presented. And the reverse deformation distribution of blade is obtained.

Jan 1, 2010

By Verya Nasri, Mehdi Bakhshi

"Fiber reinforcement has emerged as an alternative to steel bars in precast concrete segments due to advantages such as saving cost and reducing production time while developing a more robust product with improved handling and long-term durability. ACI recently drafted a new report as the first design guideline on FRC tunnel segments to provide specific guidance for this emerging technology. ACI document offers general information on the history of FRC precast segments from tunneling projects throughout the world; a procedure for structural analysis and design based on governing load cases, and a description of the material parameters, tests and analyses required to complete the design. This paper summarizes the design considerations in this ACI guideline prepared by the authors of this paper as the main contributors. Application of this guideline to design of a tunnel with an internal diameter of 5.5 m (18 ft) results in elimination of steel bars.INTRODUCTIONPrecast concrete segments are installed to support the tunnel excavation behind the Tunnel Boring Machine (TBM) in soft ground and weak rock applications. The TBM advances by thrusting off the completed rings of precast concrete segments that provide both the initial and final ground support as part of a one-pass lining system. These segments are typically designed to resist the permanent loads from the ground and groundwater as well as the temporary loads from production, transportation and construction. Tunnel segments are generally reinforced to resist the tensile stresses at both the Serviceability (SLS) and the Ultimate Limit States (ULS). With traditional rebar, a significant amount of labor is needed to assemble the cages and place the rebar, which results in higher production costs.Fiber Reinforced Concrete (FRC) can be used to enhance the production, handling, and placement of precast concrete segments. This is because of the uniform dispersion of fibers throughout the segment to include the concrete cover, which is very advantageous for resisting the bursting and spalling stresses. These stresses develop as a result of the high loads induced on the segments during the TBM jacking process. The presence of fiber in the concrete matrix helps mitigate against unintentional impact loads during segment handling and tunnel construction operations."

Jan 1, 2016

By G Veillette, B Parker, S Hart

This paper provides a history of the challenges that were experienced while treating both the clayey oxide gold ores and the supergene copper-gold ores at the Boddington Gold Mine during the period 1989 to 2001. However the bigger challenge was to find a process flow sheet that would allow the economic treatment of the large low-grade competent gold-copper resource that underlies the oxide and supergene gold resource. Metallurgical test work and engineering studies on this resource started in the mid 1990s and culminated in the approval in 2006 of the 35 Mtpa Boddington Expansion Project to treat this material. The process flow sheet provides the basis of an energy efficient comminution circuit that includes high pressure grinding rolls and a treatment circuit with gravity separation, flash and conventional flotation to produce a precious metal low-grade copper concentrate followed by cyanide leaching of the rougher-scavenger and cleaner tailings streams. The treatment circuit allows maximum removal of copper minerals prior to cyanide leaching and so provides an environmentally responsible tailings disposal circuit.

Jan 1, 2007

A Study on Main and Interaction Effects of Operating Variables of Column Flotation

Sep 13, 2010

By Norman O. Lotter, Virginia Lawson, Mika Muinonen, Dominic Fragomeni, Jorge F. Oliveira

Development of metallurgical flowsheets from drill core to production of finished metal involves two main domains: process mineralogy to sample the ore and develop a successful flowsheet producing saleable concentrate; and extractive metallurgy to convert that saleable concentrate to finished metal. Effective flowsheet development for a new or brown-field concentrator and processing facility is essential to project schedule and return on investment. Over the last decade in particular, the integration of geology, mineralogy, sampling, and mineral processing have empowered the development of an improved practice in flowsheet development. The use of geometallurgical units as a basis for best-practice sampling delivers representative study material to the laboratory. Modern automated mineralogy characterises the whole rock assembly and paymetal mineral hosting, to address downstream process implications. Batch scale flotation testing then uses this information to design and perform well-focused strategies. At early stages of the project, the Extractive Metallurgy team is engaged to determine processing constraints or other economic drivers in conversion of the saleable concentrate into finished metal. The team evaluates available technologies, assesses the impurities and key properties of the given concentrate. In many cases, changes to mineral processing flowsheet are required to maximize value per tonne of concentrate. Site conditions, availability of infrastructure, energy and power all play an important role. Modern metallurgical simulation tools such as FactSage™ and METSIM™ can quickly define the appropriate test program for each process. Bench scale testing and appropriate scale of piloting can confirm simulations and provide design criteria. A case study demonstrates how effective use of these tools and a multidisciplinary team can accelerate flowsheet development, while reducing costs and ensuring that the designed processing facilities maximize project value with minimum risk.

Jan 1, 2014

By CLAYTON C. BALL

In the year 1948, more than ever before, the coal industry established itself on the threshold of a new and exciting future expansion. While production did not equal the wartime and peacetime peaks of 1944 and 1947, it was, in review, a good coal year. During the latter part of the year a combination of mild weather, record stock piling, and general business slackening reduced coal demand to the extent that marginal mines suspended operations, while mines remaining active found it necessary to renew their attention to producing better products at lower operating costs.

Jan 1, 1949

By Dennis J. Callaghan

This report is the result of information obtained from a review of related literature, personal inquiry and on-site examination of active surface coal mining operations. Four improved surface coal mine systems are described in detail and evaluated for feasibility, implementation requirements, environmental benefit and costs. Engineering feasibility emphasizes equipment availability, compliance to design requirements, practicality and industry rating. Implementation potential emphasizes immediacy, ease, acceptability and constraints. Special attention was given to environmental responsiveness, both with regard to the solutions to mined-land reclamation problems and to the concurrency of reclamation. Each system description includes a hypothetical model mine with a depreciation schedule, capital summary, estimated annual production costs, sales price computation, production and operating cost summary, and a sensitivity analysis of mine price to stripping ratio. A program plan and time schedule for demonstrating a selected mining system covers site selection criteria, mine data collection, criteria for controlling and budgeting costs and reporting findings. Ten additional mining methods and techniques are briefly described and evaluated. Common reclamation problems are listed and described. Sixteen state reclamation laws and regulations are abstracted. Sixty-nine references are listed in the bibliography.

Jan 1, 1976

By Steve Kral

The mining industry has had three difficult years. Commodity prices have remained low and investor confidence in the industry has been shaken. And even though the Asian economy appears to be improving, it will be some time before this improvement will translate into better commodity price conditions for mining. In addition, increased environmental and social restrictions that have been placed on the industry in developed and developing countries have made mining a more difficult proposition. And, if that is not enough, the global mining industry has found itself in fierce competition with Internet businesses for investor capital. Despite that gloomy picture, more than 10,500 mining industry professionals from about 70 countries gathered in Toronto, Ontario March 5-10, 2000 for the Mining Millennium 2000 conference. This meeting was a joint effort between the Canadian Institute of Mining, Metallurgy and Petroleum(CIM) and the Prospectors and Developers Association of Canada (PDAC).The joint meeting also featured two trade exhibitions and more than 150speakers. PDAC’s trade show attracted about 400 exhibitors and an additional 200 in the concurrent Investors’ Exchange. CIM’s exhibition attracted about 600 equipment and service companies.

Jan 1, 2000

By P G. Self, M D. Raven, R A. Eggleton

Investigation of an abandoned quarry near Rowland Flat in South Australia identified asbestiform antigorite as the fibrous serpentine mineral mined during the 1940s to 1978 for filler applications, not amphibole asbestos or chrysotile as reported in earlier investigations. Scanning and transmission electron microscopy (SEM and TEM) and selected area electron diffraction (SAED) of individual fibres were used to confirm the identification. Chrysotile is widely regarded as the only asbestos mineral in the serpentine group. Further work was done therefore, on the geology and mineralogy of the occurrence, and the health implications were reviewed. A zone of antigorite alteration, with associated talc, is traceable for 750 m along strike of recrystallised dolomitic siltstone within Woolshed Flat Shale of Neoproterozoic age. The antigorite formed, in part, by replacement of prismatic crystals of probable tremolitic amphibole. The deposit is proximal to the Williamstown Fault and the serpentine-talc alteration is possibly due to fluids expelled along the fault during late-stage deformation in the Early Palaeozoic Delamerian Orogeny. The antigorite comprises white to pale green bundles of lath-shaped fibres that occur either as randomly- arranged equant patches after amphibole or as cross-fibre veins, both intimately mixed with calcite. Highly fibrous product was mined from the weathered zone where calcite was leached during weathering. Gentle grinding releases fibres with a high aspect ratio (>10:1) that show a wide range of fibre thickness, including a significant proportion of fibres <0.25 ¦m width. Toxicological studies on fibrous antigorite from Poland and Italy indicate that the carcinogenic potential of this form of serpentine is similar to amphibole asbestos. X-ray diffraction (XRD) and fourier-transform infrared (FTIR) techniques readily distinguish antigorite from chrysotile. Determination of asbestiform habit and confirmation of antigorite mineralogy is most reliably done using electron microscopy, preferably with SAED capability.

Jan 1, 2008

By M. Sadegh Safarzadeh, Stanley M. Howard

The two-dimensional predominance area (Kellogg) diagram (PAD) surfaces bounding the three-dimensional Cu-As-S-O system were constructed at 900 K. The computations employed gases As4O6(g), O2(g), and SO2(g) as the independent coordinate species to generate diagrams of As4O6(g) − O2(g),O2(g) − SO2(g), and As4O6(g) − SO2(g), while the third gas (As4O6, O2, or SO2) was fixed. The results indicate that there is no shared boundary between enargite (Cu3AsS4) and copper sulfate (CuSO4); however, at PO2 < 10−6 atm, PAs4O6 < 10−10 atm, and PSO2 > 10−4 atm, CuSO4 is the stable phase at 900 K. The chemical driving force for oxidation of intermediate phases between enargite and copper sulfate is substantial except for basic sulfate (CuO · CuSO4).

By M. Sadegh Safarzadeh, Stanley M. Howard

The two-dimensional predominance area (Kellogg) diagram (PAD) surfaces bounding the three-dimensional Cu-As-S-O system were constructed at 900 K. The computations employed gases As4O6(g), O2(g), and SO2(g) as the independent coordinate species to generate diagrams of As4O6(g) − O2(g),O2(g) − SO2(g), and As4O6(g) − SO2(g), while the third gas (As4O6, O2, or SO2) was fixed. The results indicate that there is no shared boundary between enargite (Cu3AsS4) and copper sulfate (CuSO4); however, at PO2 < 10−6 atm, PAs4O6 < 10−10 atm, and PSO2 > 10−4 atm, CuSO4 is the stable phase at 900 K. The chemical driving force for oxidation of intermediate phases between enargite and copper sulfate is substantial except for basic sulfate (CuO · CuSO4).

By Radianto Elprama

For the realisation of the underground railway line RandstadRail in the city area of Rotterdam a bored tunnel is under construction. Diaphragm walls up to a depth of about 40 m were used to construct the building pits for the start shaft, the Blijdorp Station and the end shaft. The water tightness of the diaphragm walls was determined by leakage tests that were executed after the construction of the walls, but prior to the excavation of the building pits. The tests showed satisfactory results with a hydraulic resistance of the diaphragm walls of at least 500 days. To determine the water tightness of diaphragm walls it is recommended to follow the specific procedure as described in this paper.

Jan 1, 2006

By Jon Y. Kaneshiro, Ed Walton, Stephen J. Navin, Robert M. Sergeant, Storer J. Boone

The Coronado Traffic Tunnel is a proposed two-lane, reversible, road tunnel, which will relieve severe peak hour congestion problems on surface streets. The tunnel will take traffic from the Coronado Bay Bridge to Naval Air Station North Island. The project will include 12.5 m (41 ft) inside diameter by 1,112 m (3,650 ft) of tunnel, 552 m(1,815 ft) of cut and cover box structure, and 400 m (1,315 ft) of open cut structure. The geology consists of predominately clean and silty sand, saturated sand, with some clay layers, requiring Earth Pressure Balance or Slurry Shield tunneling technology.

Jan 1, 2001

By Emily Wortman-Wunder

As the 2010 president of the Society for Mining, Metallurgy, and Exploration, Inc., I am pleased to present the 2010 issue of Transactions of the Society for Mining, Metallurgy, and Exploration, Vol. 328. A significant portion of the contribution that we as a professional society make is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable transfer of technology. Communication within the mining community is the key to a successful society. Through books, magazines, meetings and electronic media, we accomplish the technology exchange that is fundamental to the existence of the Society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, Pennsylvania, that resulted in the founding of AIME; those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume certainly fulfills that pledge. The 2010 Transactions is the first Transactions to take advantage of new publication technologies. It appears solely as an e-book. The decision to go to an all-digital format for this longstanding publication was a difficult one, but one which will certainly better serve the mining community. I am excited about this development and the opportunities it presents. The 2010 Transactions also contain some of the most exciting research from the past year, including new developments in mineral processing, safety and exploration. Be sure not to miss the two Minerals & Metallurgical Processing issues on the subject of gold hydrometallurgy. This 2010 Transactions comprise of a total of 78 technical papers (582 pages including index), including all 21 papers (136 pages) that were published in 2010 in the Technical Papers Section of Mining Engineering magazine (Vol. 62) and all 34 papers (231 pages) that were published in 2010 in Minerals & Metallurgical Processing (Vol. 27). Addition, this volume contains 23 papers (194 pages) that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All 78 technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our publications staff. As the 2010 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume.

Jan 1, 2010

The mineralogy and textures of a portion oC ore from the 25 level northern orebody, North mine, Broken Hill are described. This ore, in places, contains up to 70 per cent cubanite (CuFe2S3 ) which has crystallized directly with other sulphides and associated gangue minerals.Several breakdown reactions involving the cubanite are also considered.

Jan 1, 1969

The Calypso geothermal field, mapped by the R V Sonne (cruise SO-135) in 1998, includes four main sites, the Northern Vent Area (centred on 37¦ 36.7&apos;S, 177¦ 06.2&apos;E, area 1.5 km2), Central Vent Area (37¦ 39.4&apos;S, 177¦ 05.2&apos;E, 1 km2), Southern Vent Area (37¦ 41.7&apos;S, 177¦ 06.0&apos;E, 1 km2) and Mercury Vent Area (37¦ 41.3&apos;S, 177¦ 07.3 &apos;E, 0.5 km2). Hydrothermal activity at the vent sites is controlled by minor, sub-parallel NE-trending normal faults. Gas bubble trails (C02) and shimmering hot water vent from fractures and joints between large blocks of silicified volcaniclastics and in depressions in the sediments at the base of these outcrops. Measured maximum vent temperatures are between 180¦C and 201¦C. Venting fluids are at, or just below, boiling for water depths of 200 m. Rock samples recovered by dredge from the sites include massive anhydrite, clay-altered pumiceous ash, silicified volcaniclastic sediments and volcaniclastic breccias cemented by sulphur. Clay-altered samples, dominated by randomly interstratified illite-smectite and accessory chlorite, indicate formation environments of 70¦C to 90 ¦C. Native sulphur is abundant throughout the samples. Fine-grained (&lt;1 mm) disseminated pyrite and vein pyrite occurs in the clay-altered pumiceous volcaniclastics and argillites. In the Southern and Mercury Vent Areas, fine-grained orpiment, realgar and cinnabar have deposited in the sandy matrix of volcaniclastic breccias. Amongst the cinnabar, small (&lt;2 mm) beads of native Hg formed on the surface of several rocks following their recovery. These samples also contained abundant light hydrocarbons, which coat the rocks with an oily sheen.

Jan 1, 1999

By Jack Bedder, Nils Backeberg

"Native antimony metal is rare and antimony generally occurs together with gold, lead, copper and silver. There are more than 100 antimony minerals, although the sulfide mineral stibnite is the main economic mineral.Antimony enters the supply chain either as a result of mining (primary production) or recycling (secondary production). China has by far the largest antimony resources and is, as a result, the world’s center for antimony mine production. While China remains the leading primary producer, accounting for 69 percent (80.5 kt or 88,700 st) of the global 117.5 kt (129,000 st) in 2017, market consolidation and regulatory inspections across China leading to closures of facilities have caused a significant decrease in Chinese output from 115.8 kt (127,600 st) in 2015 (81 percent of global production).Tajikistan and Russia are the next largest producers of antimony after China, both ramping up production in recent years. Russia could significantly increase its supply of antimony if Polyus moves ahead with supplying 10-12 kt/a (11,000–13,200 stpy) of contained antimony from gold tailings. Australia and Bolivia are also significant mine producers outside China. The value of the different ores varies based on the metal content of the concentrates, with the most valuable gold-bearing ores sourced from Australia’s Costerfield Mine and the least valuable mercury-bearing ores sourced from the Anzob Mine in Tajikistan. On average, Bolivian and Russian ores trade at an intermediate value between those from Costerfield and Anzob. Nearly all of the rest-of-world production is exported to China, where the ores and concentrates are processed into antimony ingots and oxides.Antimony ingot production is not as widespread as is the case with antimony mine production, owing to the high levels of pollution that are associated with antimony smelting. It is for this reason that smelting has been largely confined to China and other Asian countries ,such as Vietnam and Myanmar, where environmental legislation has historically been less stringent. Tajikistan has become a growing producer of antimony ingot since 2014, coming from the commissioned metallurgical plant at the Anzob Mine.Antimony oxide production is undertaken on four continents with China being the biggest producer. There is also a considerable amount of oxide production in Europe (mainly Belgium and France), which relies on imported antimony metal feedstock, mostly from China.A new antimony project under construction by Strategic and Precious Metals Processing (SPMP) in Oman made progress in 2016 and 2017, and after producing first metal in April 2016 in test facilities, was set to be commissioned in the first quarter of 2018. Commissioning had been moved back to June 2018, with a potential ramp-up to 2-3 kt/a (2,200 to 3,300 stpy) of antimony metal by the end of 2018. SPMP is also reviewing producing antimony oxide as part of its flow sheet."

Jan 7, 2018

By LaTasha R. Swanson, Jennica L. Bellanca

Proximity detection systems (PDSs) for mobile machines have the potential to decrease injuries and fatalities. Early adopters of the technology have identified some challenges, which present an opportunity to explore and improve the integration of mobile PDSs in underground coal mines. The current research study applied the task-technology fit framework to investigate the fit between mobile PDS technology and mining relative to health and safety, from the perspective of leaders at two coal mines. Quantitative results from the study show that mine leaders evaluated mobile PDS favorably for training and ease of use, system feedback, user authorization and experience, and less favorably for safety, compatibility, task completion, and reliability. Qualitative results reveal specific task, mine, and system characteristics that may have influenced leaders’ evaluations. The study includes considerations and suggestions for safe technology integration

By LaTasha R. Swanson, Jennica L. Bellanca

Proximity detection systems (PDSs) for mobile machines have the potential to decrease injuries and fatalities. Early adopters of the technology have identified some challenges, which present an opportunity to explore and improve the integration of mobile PDSs in underground coal mines. The current research study applied the task-technology fit framework to investigate the fit between mobile PDS technology and mining relative to health and safety, from the perspective of leaders at two coal mines. Quantitative results from the study show that mine leaders evaluated mobile PDS favorably for training and ease of use, system feedback, user authorization and experience, and less favorably for safety, compatibility, task completion, and reliability. Qualitative results reveal specific task, mine, and system characteristics that may have influenced leaders’ evaluations. The study includes considerations and suggestions for safe technology integration

By Thomas Schwind, Pamela S. Moran

For short tunnels, a reinforced cast-in-place lining is not economical and shotcreteis a logical substitution. In the past, reinforced shotcrete linings have been constructed with lattice girders and welded wire fabric. For the Russia Wharf Tunnel in Boston, MA, the Contractor, with the help of the Dr. G. Sauer Corporation offered the MBTA a VECP to substitute the reinforced cast-in-place concrete lining with a steel fiber reinforced shotcrete lining. The challenge was to adequately model the ductility of the steel fiber reinforced shotcrete and to test the shotcrete prior to and during construction to assure quality control. To our knowledge, this type of numerical simulation has not been used on any other tunnels in the US.

Jan 1, 2005