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By F. D. Sutterfield

This study was conducted to provide experimental evidence on the effect of modifications of gasoline front-end composition on the photochemical specific reactivities of automotive emissions. Evaporative and evaporative-plus-exhaust emissions from an automobile operated with four fuels of different volatility and varying levels of C.-C5 olefins were irradiated in a 10040 environmental chamber at three sets of initial hydrocarbon-nitrogen oxides concentrations. Reactivity was measured and expressed in terms of rate-of-NO2 formation and dosages of oxidant, peroxyacetyl nitrate, and formaldehyde. The compositional changes that were necessary in reducing fuel volatility were found to have no significant effect on the reactivity of the emissions. However, replacing C4-C5 olefins with saturated components resulted in sharp decreases in all reactivity manifestations observed for the evaporative emission samples. A lesser influence (of C4-C5 olefin replacement) was found with the composite exhaust-plus-evaporative samples; the effect that was observed could be attributed to the evaporative emission portion of the sample. The data therefore suggest that saturation of front-end fuel olefins had no large effect on exhaust emission reactivity.

Jan 1, 1971

By L. L. Hirst

Liquid fuel oils possess certain advantages over solid fuels. Ease in handling, precision temperature control, and almost complete freedom from ash are among those considered when a liquid fuel is selected for use in industrial processing. In some instances these fuels are desirable because more heating units can e packed in a Given space where space is limited, as on snips. In other cases the' are chosen because of lower actual cost per British thermal unit absorbed, or for control of the flame to increase the capacity of furnaces, as in steel and refining.

Jan 1, 1948

By H. Robert Ensminger

The Belizean economy registered a modest real growth of 1.3% during 1981. The gross domestic product (GDP), based on current prim was $121 million' with an inflation-rate of 10%. The country received $19 million in economic aid during 1981. In early 1981, Belize'e four commercial banks raised the interest on deposits to 15% in an effort to curb capital outflow. During 1981, the financial situation deteriorated somewhat, particularly the balance of payments. For the year the total value of imports exceeded exports by almost $38 million, while the Government continued to maintain a fairly free trade policy. Import duties and term averaged about 8% on essential item and 40% on nonessential ones.

Jan 1, 1983

By Joseph C. Gillen

This paper discusses the design, construction, and performance of the support of excavation system used at The Atlantic Building jobsite. The support of excavation system had to be adaptable to the different conditions surrounding the site. These conditions included support of four historic building façades, including the nine-story Atlantic Building, as well as support of three historic row-houses along two walls. Directly adjacent to the site is the historic Ford?s Theatre and townhouse. Across a 15? alley is the American Immigration Lawyers Association (AILA) Building, and across a 30? alley is the Federal Election Commission Building and another ongoing excavation. Of historical note, these two alleys were the escape route for John Wilkes Booth following his assassination of President Lincoln. With the excavation being 53? to 58? deep, the system included driven and drilled soldier piles, drilled bracket piles, and two modified tangent walls. The bracing included tiebacks, corner braces, wales, cross lot struts, and a specially designed support system for the nine-story façade. The footprint of the excavation included 12 corners and all alleys and streets were to remain open during construction. The performance requirements for system movement at Ford?s Theatre and AILA Building were ½ inches in the horizontal direction. The modified tangent walls were used in these areas to provide stiffness. The soil conditions at the site were fill material on top of a shallow, sandy, silty, gravel layer on top of a deep layer of soft organic silt and clay. Below the silt and clay layer was fine sandy material at the subgrade.

Jan 1, 2006

By Denis Bois

La Bolivie est un pays en développement qui compte une tradition minière qui précède même l?établissement espagnol en Amérique. Pendant toutes ces années, l?exploitation minière s?est faite sans grands égards pour l?environnement. Au cours des dernières années cependant, le gouvernement bolivien a modifié ses lois afin de rendre nécessaire la prise en compte de l?environnement dans le processus d?exploitation d?une mine. Dans le cadre d?un projet MRN-ACDI1 visant à renforcer le secteur minier en Bolivie et ses retombées pour la population, l?URSTM2 a été mandaté pour développer et mettre en place un programme académique de gestion environnementale minière, basée sur l?expertise canadienne. Ce programme vise à renforcer les institutions académiques boliviennes responsables de la formation en environnement minier en Bolivie ainsi que les ministères et agences gouvernementales concernées.

May 1, 2001

By Tatsunori Matsumoto

In order to investigate the variation of the load-displacement relations of piles in a site, vertical load tests were carried out on 25 small diameter steel pipe piles. Out of 25 piles, 15 piles were close-ended pipe piles attached with a blade at the pile toe and 10 piles were open-ended pipe piles. To carry out these load tests in a short period, two types of rapid load test methods, Spring hammer load test and Falling mass load test, were employed. The load tests of all piles were completed in two days with 180 blows in total. In order to estimate a static load-displacement of a pile, non-linear damping method was used. It is shown from the test results that the performance of the pipe piles such as the ultimate pile resistance and the initial pile head stiffness is improved by re-driving.

Jan 1, 2006

By Ryan C. Linthicum

A system of steel sheeting and multiple levels of high capacity double corrosion protected soil anchors were used to restrain a major slope failure that occurred at the base of the Watchung Mountains mid-way through construction of a 650,000 SF retail center along Route 22 in Watchung, New Jersey. The implementation of a design-build earth retaining structure was necessary to stabilize and repair the disturbed mountainside in a timely fashion to permit completion of the retail center on a fast track schedule. The tied back steel sheetpile wall was approximately 2,000 feet long and varied in height from 12 to 25 feet. The hillside extended approximately 350 feet above and 600 feet beyond the wall with the main failure scarp extending 50 feet above and 90 feet beyond. The wall was constructed in a top-down manner and required the installation of 475 anchors to resist loads of up to 70 kips/ft produced by the creeping hillside and groundwater flows from both a series of springs and steady state seepage through an inclined zone of fine sand. Incorporation of a unique tie point connection eliminated the need for a waler, facilitating and simplifying modifications to anchor locations based on anchor load test results and conditions encountered during construction. Post grouting also proved to be an essential element in the successful construction. This paper presents the design and the construction methods used to restrain the significant earth lateral loads produced by a slope failure using steel sheeting tied back with high capacity soil anchors with anchor loads distributed to the sheeting through a unique tie point connection on a fast track schedule. Installation techniques, testing programs, and construction quality control are also discussed.

Jan 1, 2003

By H. Sis, D. Dahlin, S. Chander, C. Summers

Bench-scale selective-flocculation tests were conducted on samples of Florida and Western phosphate process tailings. Physical, mineralogical, and surface characteristics were determined for both types of samples. The flocculation tests investigated dispersant and flocculant types and doses, pH, and slurry percent solids, while other parameters were held constant. Where selectivity was achieved, phosphate minerals remained dispersed, whereas silicate minerals flocculated and settled. In single-stage tests, flocculants having low to medium anionic character effectively upgraded products at moderately elevated pH. Multiple-stage tests, and tests in which flocculants of lower molecular weight were used as site-blockers, gave improved results.

Jan 1, 2002

By A L. Welsh, P S. Newling

Mill operators are entrusted to manage what are normally the largest capital assets on any mine site. Achieving maximum utilisation and lowest costs that drive operating margins are realised by applying well known fundamentals of good housekeeping and proactive (as opposed to reactive) maintenance programmes. Historically, maintenance and operations staff are bought in late during the construction stage and often do not have the time, know how or tools to put in place (let alone train the incumbent staff) a functioning maintenance system before commissioning starts. They then get drawn into a reactive maintenance paradigm as teething problems post commissioning are dealt with and day to day issues envelop the line tradesmen and supervisors. Additionally, even when some semblance of a planned maintenance system is established, it is often the case that over time personnel and cultural issues mask the development of problematic maintenance practices. As has been observed by the authors on many occasions, even when some basic programmed maintenance system is in place, the collection of maintenance data is often inaccurate, incomplete and not subject to analysis. The net result is of course a high incidence of machine failure leading to lower than expected availability, which ultimately translates to lower revenue and higher net maintenance costs. The time taken and the cost to repair a failed machine is always greater than the timely and planned repair of a worn machine.Upon review of a number of processing plants around the world, especially gold and small base metal operations, it is apparent that companies need to implement maintenance systems whereby the operators are not overwhelmed with data and can manage by exception. Inadequate or inaccurate data collection and analysis result in poor decisions being made and misguided actions taken. GR Engineering Services (GRES) has developed a system to enable the custodians of mining plant assets to make more effective and effective use of maintenance data by being able to focus on the indicators of plant deterioration and to programme concurrent maintenance activities to maximise plant availability and utilisation.This paper outlines the structures that can be employed to address the challenges of implementing a proactive asset management system. The best practice strategies described herein have been based on the fundamentals of a sound asset management framework:a phased approach to the development of Asset Management methodology and processeseffective implementation of programmed maintenance routinesmanaging asset condition data collected from various sourcesefficient analysis of asset data and management by exceptioninterfacing asset management data with Computerised Maintenance Management System (CMMS) and Electronic Management Systems (EMS) systemstips to assist with maximising asset performance.CITATION:Welsh, A L and Newling, P S, 2015. Operating strategies for custodians of company assets creating wealth, in Proceedings MetPlant 2015, pp 338–352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

On June 4, Kennecott Utah Copper (KUC)marked the centennial of the founding of the original company. Bill Champion is president and chief executive officer of KUC. He said, “What has happened during the past 100 years far surpassed even the most optimistic visions of men like Daniel C. Jackling and Robert Gemmell when they promoted the concept of mass production techniques for a low-grade deposit of copper ore. At that time, it was a totally new way of doing things and the mining leaders of that day scoffed at the idea. They said it would never work,” Champion said. The company will celebrate this once-in-a-lifetime occasion with a few special projects, mainly for the benefit of our employees, said Louie Cononelos, director of government and public affairs for KUC. The company has designed and minted a commemorative copper coin that reflects early steam shovel and locomotive operations on one side, and today’s modern electric shovels and huge haulage trucks on the other side. “The history of the company stems from the ores of the Bingham Canyon Mine. That coin has been encased as part of a10-panel brochure that captures the company’s 100 year history,” he said. KUC also developed special centennial banners and comparable framed posters that were displayed throughout its operations and at selected community locations that have enjoyed a long-time partnership and special relationship with the company. Some of the plants also designed their own centennial hardhat decals.

Jan 1, 2003

By A. Davis, C. Webb, J. Sorensen

The abandoned Belle Eldridge Mine near Deadwood, South Dakota, is on land controlled by the U.S. Bureau of Land Management (BLM). The mine produced lead and zinc during the first half of the 1900s. Because of acidic drainage and elevated levels of metals in tailings and waste rock, the site was evaluated in 1998 and 1999. After evaluation, the mine was remediated during 1999-2001 by the BLM. Since remediation, values of pH in water samples have been nearly neutral and specific conductance values have been much lower than before remediation. The Grizzly Gulch forest fire of July, 2002, consumed much of the Belle Eldridge site and resulted in greater than normal erosion and sediment flushing during the months following the wildfire. Had the site not been remediated and the tailings emplaced within a capped repository, generation of acidity and off-site migration of heavy metals within sediments could have been severe at downstream locations.

Jan 1, 2007

By A. Eccles

Phase designs are the foundation upon which all open pit mine sequence optimizations and budgets should be built. Unfortunately, at times, mine engineers skip the step of developing realistic pit phase designs - designs that include access ramps and mineable widths. Without mineable phase designs, their optimized schedules are based on theoretical pit shells or ?quick-and-dirty? plans with no ramps. The output from such optimizations is almost always overly optimistic. Without mineable designs, the production estimates are misleading, because they overestimate ore, and underestimate waste stripping requirements. Worse yet, when plans are not based on realistic phase designs, they can point to exactly the wrong decision in feasibility studies (i.e. ?go? when it should be ?no-go?). This paper discusses the importance and features of good pit phase design, and demonstrates the pitfalls of relying on optimized production sequences that are not based on properly designed pit phases.

Feb 27, 2013

By Paul Eger

The use of wetlands to treat mine drainage has become increasingly common, particularly as more information is available on their operation and construction. However, the lifetime of each system is still, at best, an estimate. Treatment lifetime depends on the types of processes that provide the majority of the metal removal. Anaerobic systems (vertical flow systems) rely primarily on sulfate reducing bacteria, which reduce sulfate to sulfide and generate alkalinity. Metals can be precipitated as sulfides, and acidity is neutralized. These systems can remove over 90% of the metals and increase pH from around 4 to over 7. The bacteria will remain active as long as the system remains anaerobic and contains an adequate supply of sulfate and small chain organics. Although estimates of lifetime made on the total carbon in the system suggest that lifetime should exceed 20 years, data from field and laboratory studies show that the rate of sulfate reaction decreases with time, and that after several years rates decreased substantially. To maintain acceptable treatment, either additional organic material must be added or the total metal and acid load to the system would need to be reduced substantially. Aerobic systems (overland flow wetlands) can effectively remove metals from neutral mine drainage by reactions with organic material in the substrate. Over 90% of the copper and nickel have been removed in aerobic systems treating mine drainage in Minnesota. The primary removal processes in these systems include adsorption, ion exchange and complexation, which are finite; removal will cease unless new removal sites are generated. Two wetlands built in Minnesota have been successfully treating mine drainage for 12 years. At one of the wetlands, the annual production of new removal sites has been estimated to be equal to the annual metal input, and, as a result, metal removal should theoretically continue indefinitely.

Jan 1, 2005

By J. Kabuya Mukendi, F. Brunet, J. Hadjigeorgiou, P. Matte, D. Leblanc, M. Grenon

La stabilité des bancs miniers est un élément important de la conception des fosses. Il n’y a pas de consensus sur les critères à utiliser pour évaluer la fiabilité des bancs miniers. Lors de la conception des fosses, la fiabilité des bancs miniers est analysée à l’aide d’un ou deux critères. L’objectif de cet article est d’analyser l’efficacité de la conception des bancs miniers de la fosse Tiriganiaq du projet minier Meliadine par rapport à des critères de fiabilité rencontrés dans la littérature et la pratique. L’article présente les similitudes et les différences entre les résultats obtenus pour les différents critères et propose une approche multicritère systématique pour évaluer la fiabilité des bancs miniers à l’aide de cartes de susceptibilité.

Jan 1, 2012

By D McClelland, R Whittering

Minerals and Metals Group (MMG) subsidiary Lane Xang Minerals Ltd operates a single site copper and gold mine near Sepon in Lao PDR. Gold production commenced in 2002 and first cathode copper production was in March 2006. Plant throughputs for gold and copper are currently 2.5 Mt/yr and 1.4 Mt/yr respectively; use of a second tailings dam has commenced accordingly. Although the increased catchment area creates opportunities for more storage to reduce demand on other water sources, especially during the dry season, it also creates greater requirements for water treatment capacity.The water balance for mining operations in a tropical monsoon environment with dry winters presents on going management challenges. A successful mining operation depends on a careful balance of water inputs and outputs. The challenge prior to every wet season is having enough storage capacity to absorb potential rainfall. Plant operation in the dry season benefits from water captured and stored from the wet season which reduces the dependence on river water. Release of excess water to the environment is necessary to cope with the overall positive water balance and depends on suitable and effective treatment of water in accordance with the environmental guidelines.Ausenco has recently built and commissioned a second water treatment plant at the Sepon Copper Plant to process tailings decant water.  The objective of the second Sepon water treatment facility is to increase the site water discharge capacity to maintain the water balance and reduce the dependence on river water.  Decant water treatment is required to precipitate the contained heavy metals prior to discharging to surrounding wetlands.  The main metal that needs to be removed from the site water to meet discharge water quality requirements is manganese, as heavy metals are already precipitated to required levels in neutralisation before the tailings are sent to the storage facilities. A site layout provision for removal of manganese to produce a saleable carbonate precipitate is incorporated in the polishing plant design (future installation).

Jan 1, 2009

By Donald L. Siebert

This profile study of the commercial secondary aluminum industry examines not only the elements that form the industry but also the technological contributions of each toward industrial growth. Concise descriptions of processing methods trace aluminum scrap from generating sources to marketable industrial and consumer goods. Economic and marketing appraisals are used to illustrate the impact that recent technology has had upon the secondary aluminum industry. Price, supply, demand, competition, and substitutes are selected as components of an economic model of the secondary industry and are used to illustrate the aggregate effects of technological changes. The final section is a conceptual look at the future in which sensitive economic indicators (such as die casting in the automotive and appliance industries) are examined as well as the problems of conserving mineral resources by retrieving secondary aluminum from solid waste.

Jan 1, 1970

By Pilon CG, Deakin RC

It is proposed that a waste rock dump be constructed on slopes consisting of soft colluvium and weathered Chim Formation mudstone at the Porgera Gold Mine, in Enga Province, Papua New Guinea (PNG). Geolog- ical, geomorphological and geophysical investigations were conducted in support of geotechnical studies to assess the physical character of the 6km2 site. Geomorphological studies focused on the extent and nature of colluvium cover and landslide activity. Detailed ground traverse mapping resulted in classification and delineation of eight terrains and seven material types. Seismic refraction and resistivity profiling, combined with drilling, provided subsurface data. Results were presented as standard profiles, coloured contoured sections and plans. Subsurface features, including deep colluvial channels, buried cliffs, slump blocks and buried alluvial channels, were identified. Results of the combined investigations allowed designers to model the colluvium/ bedrock surface and identify critical areas of deep, mobile colluvium and weak bedrock. A design approach was developed which accounted for the morphology of landslide systems and distribution of colluvium types.

Jan 1, 1991

By Jean-François Dorion

La corrosivité des environnements miniers souterrains est un phénomène peu étudié au Canada. En plus de détériorer les systèmes de soutènement, la corrosion s?attaque aussi à divers installations et équipements souterrains. Cette étude, débutée en janvier 2007, est l?établissement d?une banque de données afin de caractériser les environnements miniers souterrains selon leur potentiel de corrosivité pour les systèmes de support de terrains. Pour ce faire, cinq (5) mines ont été sélectionnées afin de comparer les environnements : Laronde, Géant-Dormant, Niobec, Mouska et Doyon. À chacune des mines, trois (3) endroits ont été étudiés. Les résultats préliminaires démontrent une grande variabilité des conditions d?une mine à l?autre ainsi qu?à l?intérieur même d?une mine. La minéralogie des roches et du gisement influence la composition des eaux souterraines et la présence des sulfures joue un rôle important sur l?agressivité de l?eau et de l?air des mines de l?étude. Afin de déterminer le potentiel de corrosivité, plusieurs paramètres doivent être considérés et la mine doit être zonée selon l?agressivité des endroits.

Feb 1, 2008

By Paul Downing

A typical day for a blasting company includes what seems to be an infinite list of tasks dealing with numbers. Whether determining the exact amount of explosives material in inventory, the number of holes in the shot, the exact distance from the blast site to the nearest exposure, or the capacity of bulk hoppers, the accuracy of numbers is key to ensuring the safety of the public, property and personnel.

Jan 1, 2008

By K. C. Armstrong, A. B. Cron, L. A. Melis

"The Johnny Mountain gold mine in northern British Columbia, owned by skyline Gold Corporation, has been in operation since August 1988. Mill operating difficulties at the start of the operation resulted in a depleted cash flow situation and quick improvements were required to generate a self-sustaining financial basis of operation. In October 1988, Melis Engineering Ltd. was contracted to identify metallurgical difficulties, implement necessary modifications, and undertake mill operations and personnel training in order to achieve production targets.This paper presents the operating difficulties which existed at start-up and describes the methodology used to overcome production problems. Metallurgical testing results are described along with the modifications made to the milling circuit to suit ore metallurgy. Plant changes led to the operation of a simple gravity/flotation circuit to recover gold as bullion and in a copper concentrate. Operation of the originally installed cyanidation circuit was discontinued. This contributed to substantial savings in operating costs and virtually eliminated environmental problems. PROPERRTY LOCATION ANR DESCRIPTIONThe Johnny Mountain mine site is located in northern British Columbia along the Iskuit River about 60 km east of Wrangell, Alaska and 275 km north of Terrace, B. C.. A location map is presented in Figure 1 and a site plan is shown in Figure 2. The complex is located on a mountain plateau about 3, 600 feet above sea level. The plateau is flanked to the north by Johnny Mountain and surrounded on the other sides by steep cliffs."

Jan 1, 1990