Laboratory SIP signatures associated with oxidation of disseminated metal sulfides

Edmundo Placencia-Gómez, Lee Slater, Dimitrios Ntarlagiannis, Andrew Binley

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23 Scopus citations


Oxidation of metal sulfide minerals is responsible for the generation of acidic waters rich in sulfate and metals. When associated with the oxidation of sulfide ore mine waste deposits the resulting pore water is called acid mine drainage (AMD); AMD is a known environmental problem that affects surface and ground waters. Characterization of oxidation processes in-situ is challenging, particularly at the field scale. Geophysical techniques, spectral induced polarization (SIP) in particular, may provide a means of such investigation. We performed laboratory experiments to assess the sensitivity of the SIP method to the oxidation mechanisms of common sulfide minerals found in mine waste deposits, i.e., pyrite and pyrrhotite, when the primary oxidant agent is dissolved oxygen. We found that SIP parameters, e.g., phase shift, the imaginary component of electrical conductivity and total chargeability, decrease as the time of exposure to oxidation and oxidation degree increase. This observation suggests that dissolution-depletion of the mineral surface reduces the capacitive properties and polarizability of the sulfide minerals. However, small increases in the phase shift and imaginary conductivity do occur during oxidation. These transient increases appear to correlate with increases of soluble oxidizing products, e.g., Fe2 + and Fe3 + in solution; precipitation of secondary minerals and the formation of a passivating layer to oxidation coating the mineral surface may also contribute to these increases. In contrast, the real component of electrical conductivity associated with electrolytic, electronic and interfacial conductance is sensitive to changes in the pore fluid chemistry as a result of the soluble oxidation products released (Fe2 + and Fe3 +), particularly for the case of pyrrhotite minerals.

Original languageEnglish (US)
Pages (from-to)25-38
Number of pages14
JournalJournal of Contaminant Hydrology
StatePublished - 2013

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Water Science and Technology


  • AMD
  • Dissolution-depletion
  • Oxidation products
  • Oxidative-weathering
  • Spectral induced polarization
  • Sulfide minerals


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