Integrated geophysical and geochemical study on AMD generation at the Haveri Au–Cu mine tailings, SW Finland

Abstract

The Haveri tailings area contains 1.5 Mt of sulfide-bearing waste from the Au-Cu mine that operated during [1942][1943][1944][1945][1946][1947][1948][1949][1950][1951][1952][1953][1954][1955][1956][1957][1958][1959][1960][1961]. Geophysical and geochemical methods were used to evaluate and characterize the generation of acid mine drainage (AMD). Correlations were examined among the electrical resistivity tomography (ERT) data, the total sulfide content and concentrations of sulfide-bound metals (Cu, Co, Fe, Mn, Ni, Pb and Zn) of tailings samples, and the resistivity and geochemistry of surface water. The resulting geophysical-geochemical model defines an area in the vadose tailings, where a low resistivity anomaly (\10 Ohm m) is correlated with the highest sulfide content, extensive sulfide oxidation and low pH (average 3.1). The physical and geochemical conditions, resulting from the oxidation of the sulfide minerals, suggest that the low resistivity anomaly is associated with acidic and metal-rich porewater (i.e., AMD). The lower resistivity values in the saturated zone of the central impoundment suggest the formation of a plume of AMD. The natural subsoil layer (silt and clay) and the bedrock surface below the tailings area were well mapped from the ERT data. The detected fracture zones of the bedrock that could work as leakage pathways for AMD were consistent with previous geological studies. The integrated methodology of the study offers a promising approach to fast and reliable monitoring of areas of potential AMD generation and its subsurface movement over large areas (ca. 9 ha). This methodology could be helpful in planning drill core sampling locations for geochemical and mineralogical analysis, groundwater sampling, and choosing and monitoring remedial programs.

Electrical Resistivity Tomography as a Support Tool to Estimate Physicochemical Properties of Mining Tailings Pond

“…The higher content of fine materials joined to the higher concentration and mobility of metals in G1 support the lower resistivity values found in this profile compared to profiles G2 and G3. A similar behaviour was observed in others tailings ponds from Cartagena-La Unión mining district (Spain) [64], Ursk (Russia) [65] or Viljakkala (Finland) [66]. The negative correlation suggests that the water content, fine and medium particle sizes and the presence of metals, especially in its bioavailable and soluble fractions, is followed by low values of electrical resistivity [61,67,68].…”

Long-term lake sediment records and factors affecting the evolution of metal(loid) drainage from two mine sites (SW Finland)

“…n = number of samples; na = not analyzed; ( ) = concentration of sample from lake bottom; * = single analysis of water in direct contact with tailings. Results for Ylöjärvi from the HERTTA database and results for the Haveri mine after Parviainen, 2009 of dissolved oxidation products occurs in the percolating pore water of the tailings pile, ending up in the groundwater body beneath it instead of surface water runoff (Parviainen, 2009;Placencia-Gómez et al, 2010).…”

Sustainable rehabilitation of mining waste and acid mine drainage using geochemistry, mine type, mineralogy, texture, ore extraction and climate knowledge

“…In general, ore minerals are extracted by various mechanical, physical and chemical processes that generate multiple grain size fractions and surface area in the tailings, and the potential for exposure to air. The electrical resistivity tomography can investigate the internal structure, mineral and grain-size variation of mining wastes (Placencia- Gomez et al, 2010). The variations in microtexture of ore deposit and grain size of the post-mining wastes can produce variable amount of acidity and contamination (Hakkou et al, 2008a;Parbhakar-Fox et al, 2011, 2013.…”