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SUMMARY:Minerals in Mine Wastes: Resources\, Recycling\, Remediation
DTSTART:20131105T161500
DTEND:20131105T171500
DTSTAMP:20260427T230611Z
UID:32b7647b7410d572bf4faf0bc0f1b187681ef5d58740e755124e41ea
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr Karen Hudson-Edwards\, Department of Earth and Planetary Sc
 iences\, Birkbeck\, University of London (UK)\nAbstract:\nWastes produced 
 from the mining and extraction of metal\, industrial mineral and energy re
 sources constitute one of the largest waste streams on Earth. The volumes 
 of these ‘mine wastes’ are predicted to increase at least two-fold ove
 r the next 100 years due to increasing demands for minerals and energy\, a
 nd lower ore grades. Mine wastes can be gases\, fluids (e.g. acid\, circum
 neutral or basic mine drainage) and solids (flue ashes and dusts\, slags\,
  tailings\, sludges and waste rock). Solid mine wastes contain a variety o
 f minerals that can be considered as resources (and thus re-processed or r
 e-mined) or can be recycled. These minerals can also react with water and 
 air to yield secondary minerals that contain metallic and metalloid elemen
 ts\, and can thus also be considered as resources\, be recycled\, or requi
 re remediation. This presentation makes the case that knowledge of the min
 erals in mine wastes will significantly enhance the design of re-processin
 g\, recycling and remediation programmes.\nThe major minerals of mine wast
 es can be sub-divided into four categories\, namely primary sulphides\, pr
 imary non-sulphides\, compounds produced from ore processing and secondary
  minerals (Jamieson\, 2011). Many of these are micro- to nano-sized and ar
 e not easily characterised using traditional methods. A variety of traditi
 onal (e.g. X-ray diffraction\, scanning electron microscopy\, electron pro
 be micro-analysis and X-ray mapping\, etc.) and non-traditional methods (e
 .g. X-ray absorption spectroscopy\, CT scanning\, atomic force microscopy\
 , etc.) are needed for this purpose. To be able to extract economic metals
  and commodities from mine wastes\, it is important to know how they are h
 osted. Bioleaching of copper-bearing mine wastes\, for example\, is most e
 ffective when the copper-bearing minerals are well-characterised\, and the
  mechanisms by which bacteria interact with the mineral surfaces are under
 stood and can be managed. An understanding of the concentrations\, types\,
  sizes and bonding environments of impurities in these copper-bearing mine
 rals is also important in terms of understanding how these might negativel
 y impact on the bacteria. Metal recovery from acid mine drainage wastes re
 lies on knowledge of which minerals can precipitate from these fluids\, an
 d how they can sorb and host the metallic elements.\nA thorough understand
 ing of the minerals is necessary in order to be able to safely (i.e.\, no 
 negative environmental impacts) and effectively use them in recycling prog
 rammes. For example\, the recycling of iron oxide- and oxyhydroxide-bearin
 g mine wastes as pigments is being piloted\, but relies on these phases be
 ing insoluble and unreactive\, since they can contain contaminants such as
  chromium\, copper and cobalt that could potentially be released to the en
 vironment.\nThe development of remediation technologies can also benefit f
 rom a thorough understanding of the mine waste minerals. For example\, cha
 racterisation of the sulphides and gangue minerals present helps in the pr
 ediction of acid\, neutral or basic mine drainage\, the concentrations of 
 potentially toxic elements (e.g.\, arsenic\, antimony\, thallium) in these
  fluids (e.g.\, Kossoff et al.\, 2011)\, and the design of appropriate rem
 ediation schemes. In cases where remediation is not possible due to the la
 rge-scale and/or dynamic nature of mine waste-affected environments (e.g.\
 , river systems)\, management of the contamination is most desirable. In t
 hese situations\, knowledge of the stability of the mineral contaminant ho
 sts is important for prediction of the contaminants most likely to be mobi
 lised. The talk will present the above material and examples\, and outline
  the ways forward for research in this area.Dr Karen Hudson-Edwards\, read
 er in Environmental Geochemistry and Mineralogy at the University of Birbe
 ck London\, is an environmental geochemist / mineralogist\, one of her fie
 lds of interest lies in the processes and products of the biogeochemical c
 ycling of contaminants and nutrients in mine wastes\, waters\, dusts and c
 ontaminated land. Her other research areas focus on chemical weathering\, 
 environmental mineralogy and mineral-organic interactions\, in particular.
 References\nJamieson\, H.E. (2011) Geochemistry and mineralogy of solid mi
 ne waste: essential knowledge for\npredicting environmental impact. Elemen
 ts\, 7\, 381-386.\nKossoff\, D.\, Hudson-Edwards\, K.A.\, Dubbin\, W.E.\, 
 Alfredsson\, M. (2011) Incongruent weathering of\nCd and Zn from mine tail
 ings: a column leaching study. Chemical Geology\, 281\, 52-71.
LOCATION:GR A3 31 http://plan.epfl.ch/?room=GR%20A3%2031
STATUS:CONFIRMED
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