Mining is an important industry, accounting for 6.9% of global GDP. However, global development promotes accelerated demand, resulting in the accumulation of hazardous waste in land, sea, and air environments. It reached 7 billion tonnes of mine tailings generated yearly worldwide, and 19 billion solid tailings will be accumulated by 2025. Adding to this, the legacy of environmental damage from abandoned mines is worrying; there are around 10,000 abandoned mines in Canada, 50,000 in Australia, and 6000 in South Africa, as well as 9500 coal mines in China, reaching 15,000 by 2050. In this scenario, restoration techniques from mining tailings have become increasingly discussed among scholars due to their potential to offer benefits towards reducing tailing levels, thereby reducing environmental pressure for the correct management and adding value to previously discarded waste. This review paper explores the available literature on the main techniques of mining tailing recycling and reuse and discusses leading technologies, including the benefits and limitations, as well as emerging prospects. The findings of this review serve as a supporting reference for decision makers concerning the related sustainability issues associated with mining, mineral processing, and solid waste management.
Solid waste management is a challenge for municipalities mainly due to the increasing generation of residues worldwide. Much waste still ends up in landfills, either as a final disposal sink, or as a temporary yet long-term storage prior to eventual landfill mining. Through degradation and infiltration processes, these materials threaten groundwater, soil and the environment, invariably causing expressive societal concern. Waste managers, environmentalists and regulators alike focus upon predicting how these complex geochemical systems will evolve over decades. Geochemical modeling and transport simulation are commonly used to support the design, operation or characterization of these dynamic systems. In this targeted critical review of the literature over the last two decades concerning geochemical modeling applications to waste disposal (including municipal, incineration residue, and industrial), we have attempted to provide an assessment of the current state of knowledge in this field, supported by a comprehensive list of modeling methodologies and data analyses, relevant for municipal solid waste (MSW) management systems. The information provided is meant to be useful for specialists when planning, implementing or adapting MSW systems.
O artigo analisa a reação do mercado de capitais após o acidente ambiental da mineradora Samarco. A Samarco se organiza como joint venture societária dividida igualmente entre a empresa brasileira Vale e a empresa anglo-australiana BHP Billiton. Foi adotada a técnica de estudo de eventos para calcular o risco sistemático (beta) e avaliar as variações no retorno das ações de empresas do setor de mineração dos mercados de capitais brasileiro e australiano. Os dados utilizados na pesquisa foram obtidos no BM&FBovespa para as empresas brasileiras e na Australian Securities Exchange (ASX) para as empresas australianas, ao longo do ano de 2015. Os resultados da pesquisa evidenciam que, no mercado brasileiro, apenas a empresa Vale apresentou um declínio significante do coeficiente beta. Em relação às empresas australianas houve declínio no risco sistemático para as empresas BHP Billiton, Rio Tinto e NCM. O rompimento da barragem de Fundão da mineradora Samarco entrou para o rol dos desastres ambiental globais. No entanto, os impactos econômicos, ambientais e sociais foram rapidamente absorvidos pelo mercado de capitais, e não influenciaram o valor das ações de empresas do setor de mineração no Brasil e na Austrália a longo prazo.
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