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Mining Operations (mining + operations)
Selected AbstractsDecolonising, Multiplicities and Mining in the Eastern Goldfields, Western AustraliaGEOGRAPHICAL RESEARCH, Issue 1 2003Leah M. Gibbs In this ,postcolonial' era, peoples and places around the globe continue to face ongoing colonisation. Indigenous peoples in particular experience colonisation in numerous forms. Despite recent attempts to ,decolonise' indigenous spaces, hegemonic systems of production, governance and thinking often perpetuate colonial structures and relationships, resulting in further entrenched colonisation or ,deep colonising' (Rose, 1999). The interface between indigenous communities and the mining industry provides fertile ground for the tensions emerging between decolonising and deep colonising. Gold mining operations at Placer Dome's Granny Smith mine in the Eastern Goldfields of Western Australia present a valuable case study for examining this tension. Changes taking place at the mine site are decolonising in intent, though outcomes may be deep colonising in effect. Recent discussions among cultural geographers over meanings of place, Ollman's (1993) notion of vantage point and a broadly postcolonial literature inform consideration of this tension. Acknowledgment and incorporation of multiple vantage points into new resource management systems allows current hegemonic approaches to be rethought, and provides insights for the shift towards genuinely decolonising processes. [source] Abrasiveness Testing, Quo Vadis?GEOMECHANICS AND TUNNELLING, Issue 1 2008A Commented Overview of Abrasiveness Testing Methods The growing economic pressure on tunnelling and mining operations has lead to an increasing importance of investigation methods for assessing the abrasiveness of rock and soil. Such investigations can be based on a wide variety of testing procedures and standards covering a wide span of scale, ranging from real-scale tests on site to model tests with simplified tools and microscopic and chemical analyses of rocks and minerals. This paper gives an overview over some of the most important procedures, technical aspects of their application, classification of testing results and the current state of experience. Abrasivitätstest, quo vadis? Ein kommentierter Überblick über Abrasivitäts-Testverfahren Der stetig zunehmende wirtschaftliche Druck auf Tunnelbau und Rohstoffgewinnung führt zu einer steigenden Bedeutung von Untersuchungsverfahren zur Bewertung der Abrasivität von Fest- und Lockergesteinen. Derartige Untersuchungen können mit einer Vielzahl von Verfahren durchgeführt werden, die von Untersuchungen vor Ort im Realmaßstab über Modellversuche mit vereinfachten Werkzeugen bis hin zu mikroskopischen oder chemischen Untersuchungen eine weite Bandbreite an Untersuchungsmaßstäben einschließen. Der vorliegende Beitrag soll einen Überblick über die derzeit wesentlichsten Untersuchungsverfahren, versuchstechnische Aspekte, angewandte Klassifizierungsschlüssel sowie Einsatzerfahrungen mit den jeweiligen Verfahren geben. [source] Probabilistic analysis of underground pillar stabilityINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 8 2002D. V. Griffiths The majority of geotechnical analyses are deterministic, in that the inherent variability of the materials is not modelled directly, rather some ,factor of safety' is applied to results computed using ,average' properties. In the present study, the influence of spatially varying strength is assessed via numerical experiments involving the compressive strength and stability of pillars typically used in underground construction and mining operations. The model combines random field theory with an elasto-plastic finite element algorithm in a Monte-Carlo framework. It is found that the average strength of the rock is not a good indicator of the overall strength of the pillar. The results of this study enable traditional approaches involving factors of safety to be re-interpreted as a ,probability of failure' in the context of reliability based design. Copyright © 2002 John Wiley & Sons, Ltd. [source] Abandoned artisanal gold mines in the Brazilian Amazon: A legacy of mercury pollutionNATURAL RESOURCES FORUM, Issue 1 2002Marcello M. Veiga The modern gold rush in the Brazilian Amazon attracted millions of people to become artisanal miners in order to escape complete social marginalization. The rudimentary nature of artisanal mining activities often generates a legacy of extensive environmental degradation,both during operations and well after mining activities have ceased. One of the most significant environmental impacts is derived from the use of mercury (Hg), which is illegal for use in gold amalgamation in Brazil, but continues to be the preferred method employed by artisanal gold miners. The general population is unaware of the capricious nature of mercury and artisanal mining activities. Moreover, individuals in positions of political or economic infiuence tend to be negatively biased towards artisanal mining and government policies do not effectively address the realities of these activities. Affected communities have consequently been ignored,and mistrust towards outside parties is high. Not surprisingly, miners are suspicious of and unlikely to employ externally derived solutions to reduce mercury emissions. This article reviews the use of mercury in artisanal mining and highlights the role miners, governments and non-governmental organizations (NGOs) have played in communicating facts, perpetuating myths and deriving solutions for mercury pollution. This article also raises some key concerns that must be addressed to understand the behaviour of mercury in the environment and identifies solutions for problems facing communities where artisanal gold mining operations have been abandoned. [source] The stone forum: Implementing a consensus building methodology to address impacts associated with small mining and quarry operationsNATURAL RESOURCES FORUM, Issue 1 2000C. Peiter Abstract Small-scale mining, including quarry operations, continues to play an important social and economic role in hundreds of communities throughout Brazil. Often operating outside the formal economy, conflicts between the owners of small-scale mining operations, the mineworkers, various government agencies, and other stakeholders have contributed to the progressive degradation of the environment, poor health and safety standards, and low productivity. The Centre for Mineral Technology (CETEM) of Brazil is implementing a consensus building methodology in order to produce dimension stone by small-scale miners on a more sustainable basis in the Pádua region, located in the northwest of the State of Rio de Janeiro. The approach being used by CETEM is based on its own experience in working with gold prospectors in the Amazon, and lessons and experiences learned from Canadian officials and industry representatives. The lessons and insights gained from this project may prove to be useful to those involved in addressing similar problems elsewhere in Brazil, South America and around the world. [source] Bauxite Mining Restoration by Alcoa World Alumina Australia in Western Australia: Social, Political, Historical, and Environmental ContextsRESTORATION ECOLOGY, Issue 2007John H. Gardner Abstract Alcoa World Alumina Australia mines bauxite under lease agreements with the Government of Western Australia. The leases lie in the Darling Range to the east of Perth, the capital and major population center. In addition to bauxite and other mineral ores, the Darling Range is a major potable water source and harbors a species-rich forest dominated by Jarrah (Eucalyptus marginata), a significant commercial timber. Conservation and recreation are important land uses in the region. Social and political pressures have led to stringent governmental requirements for restoration. In addition, a summer drought period, a soil deficient in most nutrients, water management challenges, an introduced disease, caused by Phytophthora cinnamomi Rands, and a post-mining ecosystem that must be conducive to the prescribed burning management of the region pose significant challenges to successful restoration. Alcoa presently mines and restores approximately 550 ha per annum. Although the "footprint" at the end of the life of the mining operations represents only about 4% of the total forest estate, Alcoa is committed to restoring the forest values of the region of all lands impacted by mining. The major objective of restoration is to enhance or maintain forest values by restoring habitat and structural characteristics of the native forest environment. Completion criteria for Alcoa's mine restoration have been developed. The original Alcoa mine at Jarrahdale has been rehabilitated, and in 2005, a 975-ha area received a "certificate of completion" and was returned to the management control of the State of Western Australia. [source] Bitumen content estimation of Athabasca oil sand from broad band infrared reflectance spectraTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2010B. Rivard Abstract Oil sand is a mixture of quartz grains, clay minerals, bitumen, water, and minor accessory minerals. There is a need in oil sands mining operations for a robust method to estimate total bitumen content in real time; and so modelling of the total bitumen content (TBC) in Athabasca oil sands of Western Canada was undertaken on the basis of hyperspectral reflectance spectra. A selection of different bitumen, water, and clay mineral spectral features (3.0,30.0,µm) was used to develop broad-band TBC predictive models that have good accuracy, with less than 1.5% error with respect to laboratory methods of bitumen assay. These models are also robust, in that they are independent of mine location. Simple broad band models, based upon previously identified Gaussian features or wavelet features, provide an incremental improvement over the currently deployed industry two-band ratio model. An improved two-band model was also developed, which makes use of a combination of the same two bands but normalised to their mean. A wavelet-based, broad-band model comprised of indices and five bands, where the bands are normalised to the mean of the bands, adequately addresses the influence of water, clay, and textural variation on selected bitumen features. This five-band model appears to produce the most robust estimator of TBC, with a dispersion of ,1.1,1.5%, which can be applied to different sites within a mine and to different mines without additional tuning or calibration, as evidenced by regression slopes of 0.99,1.0 for modelling, validation, and blind data sets. [source] Assessment of organochlorine pesticides and metals in ring-tailed lemurs (Lemur catta) at Beza Mahafaly Special Reserve, MadagascarAMERICAN JOURNAL OF PRIMATOLOGY, Issue 12 2009Thomas R. Rainwater Abstract Like most of Madagascar's endemic primates, ring-tailed lemurs (Lemur catta) face a number of threats to their survival. Although habitat loss is of greatest concern, other anthropogenic factors including environmental contamination may also affect lemur health and survival. In this study, we examined ring-tailed lemurs from the Beza Mahafaly Special Reserve (BMSR), southern Madagascar for exposure to organochlorine (OC) pesticides and metals and examined differences in contaminant concentrations between sexes and among age groups, troops, and habitats. A total of 14 pesticides and 13 metals was detected in lemur blood (24 individuals) and hair (65 individuals) samples, respectively. p,p,-DDT, heptachlor, aldrin, heptachlor epoxide, endrin aldehyde, and endrin were among the most prevalent pesticides detected. Surprisingly, the persistent metabolite of p,p,-DDT, p,p,-DDE, was not detected. The most commonly detected metals were aluminum, zinc, boron, phosphorus, silicon, and copper, whereas metals considered more hazardous to wildlife (e.g. arsenic, cadmium, lead, selenium, vanadium) were not found above detection limits. Overall, concentrations of OC pesticides and metals were low and similar to those considered to be background concentrations in other studies examining the ecotoxicology of wild mammals. Few inter-sex, -age, -troop, and -habitat differences in contaminant concentrations were observed, suggesting a uniform distribution of contaminants within the reserve. Several statistically significant relationships between lemur body size and contaminant concentrations were observed, but owing to the lack of supportive data regarding contaminant exposure in wild primates, the biological significance of these findings remains uncertain. Results of this study document exposure of ring-tailed lemurs at BMSR to multiple OC pesticides and metals and provide essential baseline data for future health and toxicological evaluations of lemurs and other wild primates, especially those in regions with expanding agricultural and mining operations. Am. J. Primatol. 71:998,1010, 2009. © 2009 Wiley-Liss, Inc. 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