Características geológicas y geotécnicas de los lodos de flotación de la Sierra Minera de Cartagena-La Unión (SE España)

We present the results of a geological and geotechnical characterization of the metallurgic waste from the Sierra Minera de Cartagena-La Union. We have studied eight tailings dams from which we collected and analysed 42 samples of metallurgic waste. We measured grainsize distribution, the specific gravity of solid particles, plasticity index, permeability, both in situ and in the laboratory, direct shear characteristicsand moisture content. According to size distribution the tailings can be classified as sandy silt. Their plasticity index ranges from medium to nil. The internal friction angle varies between 28 and 42 degrees. Cohesion is between 0 and 2.2 t/m2. The specific gravity of the solid particles ranges widely from 1.8 to 4 g/cm3. The saturated hydraulic conductivity values vary between 1.3x 10-5 and 3.2x 10-9 m/s.The water content measured in situ shows that the degree of saturation remains relatively high despite low rainfall and high evaporation rates. Several tailings dams have failed. The leading causes of tailings-dam failure are: 1) slope instability; 2) overflow; 3) erosion; and 4) subsidence or collapse. The main factor leading to dam failure is that the tailings stored in the ponds are highly saturated

Lluis Marià Vidal i la geologia gironina

Sobre la figura de Lluís Marià Vidal i Carreras, enginyer de mines, geòleg i president del Centre Excursionista de Catalunya.

Relatório de estágio de biologia e geologia realizado na Escola Básica e Secundária Gonçalves Zarco

O Estágio Pedagógico (EP) é uma etapa fundamental para a preparação do estagiário, futuro professor, e é sobretudo, uma etapa reflexiva e de partilha a vários níveis: científico, pessoal, pedagógico e ético-profissional. O presente relatório de estágio visa apresentar, de forma contextualizada, as experiências de ensino/aprendizagem desenvolvidas durante a prática pedagógica realizada na Escola Básica e Secundária Gonçalves Zarco (EBSGZ), no âmbito do Mestrado em Ensino da Biologia e da Geologia no 3º Ciclo do Ensino Básico e no Ensino Secundário. Este trabalho é o resultado de um crescimento profissional reflexivo e profícuo, fundamentado numa análise crítico-construtiva do que foi realizado ao longo da Prática de Ensino Supervisionada (PES). Esta reflexão assentou essencialmente na análise dos conhecimentos teóricos e práticos adquiridos e numa atitude de questionamento sustentada por diferentes referenciais teóricos e pela vontade de agir melhor. O estágio pedagógico pressupôs uma ação reflexiva do professor estagiário em seis domínios funcionais: Prática de Ensino Supervisionada (PES), Atividades de Integração no Meio Escolar (AIME), Atividades de Intervenção na Comunidade Escolar (AICE), Atividades Complementares à Prática Letiva (ACPL), Atividades de Natureza Científico-Pedagógica(ANCP) e Outras Atividades de Enriquecimento Profissional. Cada um destes domínios visou dotar o estagiário de várias competências, estratégias e recursos que lhe permitirão exercer futuramente uma profissão integradora e desafiante.

Anaes de Escola de minas de Ouro Preto; colleções de memorias e de noticias sobre a meneralogia, a geologia e as explorações das minas no Brazil ...

Subtitle varies.

Instantaneous outbursts in underground coal mines: An overview and association with coal type

Instantaneous outbursts in underground coal mines have occurred in at least 16 countries, involving both methane (CH4) and carbon dioxide (CO2). The precise mechanisms of an instantaneous outburst are still unresolved but must consider the effects of stress, gas content and physico-mechanical properties of the coal. Other factors such as mining methods (e.g., development heading into the coal seam) and geological features (e.g., coal seam disruptions from faulting) can combine to exacerbate the problem. Prediction techniques continue to be unreliable and unexpected outburst incidents resulting in fatalities are a major concern for underground coal operations. Gas content thresholds of 9 m(3)/t for CH4 and 6 m(3)/t for CO2 are used in the Sydney Basin, to indicate outburst-prone conditions, but are reviewed on an individual mine basis and in mixed as situations. Data on the sorption behaviour of Bowen Basin coals from Australia have provided an explanation for the conflicting results obtained by coal face desorption indices used for outburst-proneness assessment. A key factor appears to be different desorption rates displayed by banded coals, which is supported by both laboratory and mine-site investigations. Dull coal bands with high fusinite and semifusinite contents tend to display rapid desorption from solid coal, for a given pressure drop. The opposite is true for bright coal bands with high vitrinite contents and dull coal bands with high inertodetrinite contents. Consequently, when face samples of dull, fusinite-or semifusinite-rich coal of small particle size are taken for desorption testing, much gas has already escaped and low readings result. The converse applies for samples taken from coal bands with high vitrinite and/or inertodetrinite contents. In terms of outburst potential, it is the bright, vitrinite-rich and the dull, inertodetrinite-rich sections of a coal seam that appear to be more outburst-prone. This is due to the ability of the solid coal to retain gas, even after pressure reduction, creating a gas content gradient across the coal face sufficient to initiate an outburst. Once the particle size of the coal is reduced, rapid gas desorption can then take place. (C) 1998 Elsevier Science.

Controlled partial mine ventiliation recirculation trial at Mount Isa Mines

The ventilation and cooling of deep, hot mines present particular problems in Australia as a consequence of the surface climate, the size of the underground voids, the degree of mechanization and the cost of power in remote areas. A preliminary investigation of the effects of controlled partial recirculation of air was conducted in Mount Isa Mines' Deep Copper section. Gas and dust concentrations were measured in the exhaust air of the major working section to assess the potential for recirculating exhaust air to the intake airways to reduce the cost of providing an acceptable working environment in the deep parts of the mine. Studies were undertaken of airborne dust deposition in vertical airways and the efficiency of usage of the ventilation air in diluting contaminants. It was established that 45% of the respirable dust was deposited in a 130-m vertical raise and 60% of the air supplied to the section could be reused or recirculated. The first major field trial of a controlled partial recirculation system in Australia was undertaken in the light of these results and demonstrated excellent potential for significant reduction in ventilation costs. Gas and dust contaminant levels were well below the threshold limit values during the trial. It is concluded that controlled partial recirculation can be a practical, effective and safe aid to normal ventilation practice in Australian deep, hot mines.

Quantifying stresses and support requirements in the undercut and production level drifts of block and panel caving mines

A numerical modelling strategy has been developed in order to quantify the magnitude of induced stresses at the boundaries of production level and undercut level drifts for various in situ stress environments and undercut scenarios. The results of the stress modelling were in line with qualitative experiential guidelines and a limited number of induced stress measurements documented from caving sites. A number of stress charts were developed which quantify the maximum boundary stresses in drift roofs for varying in situ stress regimes, depths and undercut scenarios. This enabled many of the experiential guidelines to be quantified and bounded. A limited number of case histories of support and support performance in cave mine drifts were compared to support recommendations using the NGI classification system, The stress charts were used to estimate the Stress Reduction Factor for this system. The back-analyses suggested that the NGI classification system might be able to give preliminary estimates of support requirements in caving mines with modifications relating to rock bolt length and the support of production level intersections. (C) 2002 Elsevier Science Ltd. All rights reserved.

Global trade in GM food and the cartagena protocol on biosafety: Consequences for China

The UN Cartagena Protocol on Biosafety adopted in Montreal, 29 January, 2000 and opened for signature in Nairobi, 15-26 May, 2000 will exert a profound effect on international trade in genetically modified organisms (GMOs) and their products. In this paper, the potential effects of various articles of the Protocol on international trade in GMOs are analyzed. Based on the present status of imports of GMOs and domestic research and development of biotechnology in China, likely trends in imports of foreign GM food and related products after China accedes to WTO is explored. Also, China's potential countermeasures to control and regulate imports of GMOs in line with implementation of the Protocol are discussed. China, in recent times, has increased its food and agricultural imports substantially from USA and Canada. China imported soybean 10.42 mill. tons in 2000 and about 15 mill tons in 2001, of which majority are from USA where GM soybean accounts for 60%. The plantation of US Monsanto's transgenic Bt cotton was increased to more than 1 million ha in China in 2001. Though China has paid great attention to develop biotechnology, it appears to have little scope to export GMOs and GM products. So China may consider a range of administrative measures to implement the Cartagena Protocol and to regulate its import of GMOs and GM agricultural products. Consequently, the Regulation on Safety of Agri-GMOs was issued on June, 2001 and followed three detailed rules issued in Jan. of 2002, with a priority to limit foreign GMOs importing by safety certification and labeling system. These were outlined taking into account policies adopted in Western countries such as green barriers to international trade.

Coal dust exposures in the longwall mines of New South Wales, Australia: a respiratory risk assessment

This paper presents an analysis of personal respirable coal dust measurements recorded by the Joint Coal Board in the underground longwall mines of New South Wales from 1985 to 1999. A description of the longwall mining process is given. In the study, 11 829 measurements from 33 mines were analysed and the results given for each occupation, for seven occupational groups, for individual de-identified mines and for each year of study. The mean respirable coal dust concentration for all jobs was 1.51 mg/m(3) (SD 1.08 mg/m(3)). Only 6.9% of the measurements exceeded the Australian exposure standard of 3 mg/m(3). Published exposure-response relationships were used to predict the prevalence of progressive massive fibrosis and the mean loss of FEV1, after a working lifetime (40 years) of exposure to the mean observed concentration of 1.5 mg/m(3). Prevalences of 1.3 and 2.9% were predicted, based on data from the UK and the USA, respectively. The mean loss of FEV1 was estimated to be 73.7 ml.

A New Account of the Diamond Mines of the Deccan

This account is drawn from a manuscript in Madrid National Library and till recently unpublished. It is an autobiographical account of a diamond trader who lived in Goa in the 17th century and travelled to various regions of India and elsewhere in Asia in search of diamonds. Jacques de Couttre, a flemish merchant, was a victim of the Goa Inquisition, but his diamonds won him freedom!

Governança global e transferência de política: influências do Protocolo de Cartagena na Política Nacional de Biossegurança

No contexto de governança global, analisamos o tema da transferência de política, no qual a formulação de políticas públicas é influenciada por experiências de contextos políticos diferentes. Neste sentido, questionamos de que forma o Protocolo de Cartagena influenciou a formulação da Política Nacional de Biossegurança (PNB). A pesquisa empírica foi realizada por meio de entrevistas semiestruturadas com respondentes qualificados, que atuaram direta ou indiretamente na formulação da PNB. No tratamento dos dados adotamos uma abordagem qualitativa, por meio da utilização da análise de conteúdo. Os resultados revelam que houve transferência de política no formato de aprendizado (ou lesson drawing) do Protocolo de Cartagena à PNB.

Geologia estrutural da região Povoação-Nordeste (Ilha de São Miguel, Açores)

Dissertação de Mestrado, Vulcanologia e Riscos Geológicos, 10 de Novembro de 2005, Universidade dos Açores.