Hostname: page-component-8448b6f56d-sxzjt Total loading time: 0 Render date: 2024-04-25T05:12:31.463Z Has data issue: false hasContentIssue false
  • English
  • Français

The formation-dissolution-precipitation cycle of melanterite at the abandoned pyrite mine of Genna Luas in Sardinia, Italy: environmental implications

Published online by Cambridge University Press:  05 July 2018

F. Frau
F. Frau*
Affiliation:
Dipartimento di Scienze della Terra, Università, di Cagliari, Via Trentino 51, I-09127 Cagliari, Italy
*
*E-mail: frauf@unica.it
Get access Rights & Permissions [Opens in a new window]

Abstract

At the abandoned pyrite mine at Genna Luas (Sardinia, Italy), melanterite is the most environmentally important secondary phase associated with pyrite oxidation. A complete cycle, including formation on pyrite surface, dissolution in water, precipitation from water and subsequent alteration, can be observed. The oxidation of pyrite to melanterite is related mainly to the ‘intrinsic’ features of the Genna Luas pyrite, such as its cryptocrystalline pseudo-colloidal texture. During melanterite formation on pyrite there is transient storage of Fe2+, SO42- and acidity. This is controlled mainly by wetting-drying seasonal cycles. Laboratory experiments have shown that the simple dissolution of melanterite is an acidity-generating process which affects the geochemistry of water and, indirectly, contributes to the supply of the Fe3+ required for the aqueous oxidation of pyrite. According to this geochemical model, the interaction between rainwaters and ground pyritic materials accumulated in heaps generates hyperacidic saline waters (pH = 0.6; TDS = 300 g/l) with very high SO42+ contents (203 g/l), Fe2+ contents (73 g/l), Zn contents (11 g/l), and numerous potentially toxic elements. Melanterite precipitates from these waters (SIMelanterite = 0.15, calculated using PHRQPITZ software), giving rise to attractive emerald green crystal aggregates which, when exposed to air, alter to a fine white powder composed mainly of melanterite, and minor amounts of rozenite and szomolnokite.

Keywords

melanteritepyrite oxidationhyperacidic watersenvironmental geochemistryGenna Luas minesiteSardiniaItaly
Type
Research Article
Information
Mineralogical Magazine , Volume 64 , Issue 6 , December 2000 , pp. 995 - 1006
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Alpers, C.N., Blowes, D.W., Nordstrom, D.K. and Jambor, J.L. (1994 a) Secondary minerals and acid mine-water chemistry. Pp. 247–70 in: The Environmental Geochemistry of Sulfide Mine-wastes (Blowes, D.W. and Jambor, J.L., editors). MAC Shor tcourse Handbook, 22. Mineralogical Association of Canada, Waterloo, Ontario.Google Scholar
Alpers, C.N., Nordstrom, D.K. and Thompson, J.M. (1994 b) Seasonal variations of Zn/Cu ratios in acid mine water from Iron Mountain, California. Pp. 324–44 in: Environmental Geochemistry of Sulfide Oxidation (Alpers, C.N. and Blowes, D.W., editors). ACS Symposium Series 550. American Chemical Society, Washington D.C. Google Scholar
Binetti, A. and Testa, L. (1922) Gesso e melanterite nella miniera di Funtana Perda. Res. Ass. Min. Sarda, 27, 5, 20.Google Scholar
Bini, A., Cadoni, E., Forti, P. and Perna, G. (1986) La melanterite della miniera di Montevecchio nella Sardegna sud-occidentale. Notiz. Mineral. Paleont., 48, 7–13.Google Scholar
Blowes, D.W., Reardon, E.J., Jambor, J.L. and Cherry, J.A. (1991) The formation and potential importance of cemented layers in inactive sul. de mine tailings. Geochim. Cosmochim. Acta, 55, 965–78.CrossRefGoogle Scholar
Boni, M. (1994) Recommended excursion stops – Stop 9. Pp. 314–9 in: Sedimentological, stratigraphical and ore deposits field guide of the autochthonous Cambro-ordovician of southwestern Sardinia (Bechstädt, T. and Boni, M., editors). Mem. Descr. Carta Geol. d’It., XLVIII, Parte II.Google Scholar
Borek, S.L. (1994) Effect of humidity on pyrite oxidation. Pp. 31-44 in: Environmental Geochemistry of Sulfide Oxidation (Alpers, C.N. and Blowes, D.W., editors). ACS Symposium Series 550. American Chemical Society, Washington D.C. Google Scholar
Brizzi, G., Capperi, M. and Masotti, A. (1990) La miniera di pirite di Niccioleta, Massa Marittima (GR). 3a parte. Riv. Min. It., 2, 93–103.Google Scholar
Buckley, A.N. and Woods, R.W. (1987) The surface oxidation of pyrite. Applic. Surface Sci., 27, 437–52.CrossRefGoogle Scholar
Bullough, W., Canning, T.A. and Strawbridge, M.L. (1952) The solubility of ferrous sulphate in aqueous solutions of sulphuric acid. J. Appl. Chem., 2, 703–7.CrossRefGoogle Scholar
Civita, M., Cocozza, T., Forti, P., Perna, G. and Turi, B. (1983) Idrogeologia del bac ino mine rario dell’Iglesiente (Sardegna Sud Occidentale). Mem. Ist. It. Speleologia, 2, 137 pp.Google Scholar
Cravotta, C.A. III (1994) Secondary iron-sulfate mineral s as sources of sulfate and acidity: Geochemical evolution of acidic ground water at a reclaimed surface coal mine in Pennsylvania. Pp. 345–64 in: Environmental Geochemistry of Sulfide Oxidation (Alpers, C.N. and Blowes, D.W., editors). ACS Symposium Series 550. American Chemical Society, Washington D.C. Google Scholar
Garrels, R.M. and Christ, C.L. (1965) Solutions, Minerals, and Equilibria. Harper & Row, New York.Google Scholar
Jambor, J.L. (1994) Mineralogy of sul. de-rich tailings and their oxidation products. Pp. 59-102 in: The Environmental Geochemistry of Sulfide Mine-wastes (Blowes, D.W. and Jambor, J.L., editors). MAC Shortcourse Handbook, 22. Mineralogical Association of Canada, Waterloo, Ontario.Google Scholar
Kharaka, Y.K., Gunter, W.D., Aggarwal, P.K., Perkins, E.H. and DeBraal, J.D. (1989) SOLMINEQ.88: A computer program for geochemical modeling of water-rock interactions. U.S. Geological Survey, Water-Resources Investigations Report 88-4227, 157 pp.Google Scholar
McIntosh, J.M., Silver, M. and Groat, L.A. (1997) Bacteria and the breakdown of sulfide minerals. Pp. 63-91 in: Biological-Mineralogical Interactions (McIntosh, J.M. and Groat, L.A., editors). MAC Short Course Series, 25. Mineralogical Association of Canada, Waterloo, Ontario.Google Scholar
McKibben, M.A. and Barnes, H.L. (1986) Oxidation of pyrite in low temperature acidic solutions: Rate laws and surfaces textures. Geochim. Cosmochim. Acta, 50, 1509–20.CrossRefGoogle Scholar
Nesbitt, H.W. and Muir, I.J. (1994) X-ray photoelectron spectroscopy study of a pristine pyrite surface reacted with water vapour and air. Geochim. Cosmochim. Acta, 58, 4667–79.CrossRefGoogle Scholar
Nordstrom, D.K. (1977) Thermochemical redox equilibria of ZoBell's solution. Geochim. Cosmochim. Acta, 41, 1835–41.CrossRefGoogle Scholar
Nordstrom, D.K. and Southam, G. (1997) Geomicrobiology of sul. de mineral oxidation. Pp. 361-90 in: Geomicrobiology: Interactions between Microbes and Minerals (Banfield, J.F. and Nealson, K.H., editors). Reviews in Mineralogy, 35. Mineralogical Society of American, Washington D.C. CrossRefGoogle Scholar
Palache, C., Berman, H. and Frondel, C. (1951) Dana's System of Mineralogy. Vol. II. J. Wiley & Sons, New York.Google Scholar
Parkhurst, D.L., Thorstenson, D.C. and Plummer, L.N. (1980) PHREEQE – A computer program for geochemical calculations. U.S. Geological Survey, Water-Resources Investigations Report 80-96 (1990 revision), 210 pp.Google Scholar
Pillola, G.L. (1990) Lithologie et trilobites du Cambrien inferieur du SW de la Sardaigne (Italie): implications paléobiogéographiques. Comptes Rendus Acad. Sci. Paris, 310, 321–8.Google Scholar
Plummer, L.N., Parkhurst, D.L., Fleming, G.H. and Dunkle, S.A. (1988) A computer program incorporating Pitzer's equations for calculation of geochemical reactions in brines. U.S. Geological Survey, Water-Resources Investigations Report88-4153, 310 pp.Google Scholar
Ptacek, C.J. and Blowes, D.W. (1994) Influence of siderite on the pore-water chemistry of inactive mine-tailings impoundments. Pp. 172–89 in: Environmental Geochemistry of Sulfide Oxidation (Alpers, C.N. and Blowes, D.W., editors). ACS Symposium Series 550. American Chemical Society, Washington D.C. Google Scholar
Reardon, E.J. and Beckie, R.D. (1987) Modelling chemical equilibria of acid mine-drainage: The FeSO4-H2SO4-H2O system. Geochim. Cosmochim. Acta, 51, 2355–68.CrossRefGoogle Scholar
Rimstidt, D.J., Chermak, J.A. and Gagen, P.M. (1994) Rates of reaction of galena, sphalerite, chalcopyrite and arsenopyrite with Fe(III) in acidic solutions. Pp. 2-13 in: Environmental Geochemistry of Sulfide Oxidation (Alpers, C.N. and Blowes, D.W., editors). ACS Symposium Series 550. American Chemical Society, Washington D.C. Google Scholar
Sasaki, K. (1994) Effect of grinding on the rate of oxidation of pyrite by oxygen in acid solutions. Geochim. Cosmochim. Acta, 58, 4649–55.CrossRefGoogle Scholar
Singer, P.C. and Stumm, W. (1970) Acidic mine drainage: The rate-determining step. Science, 167, 1121–3.CrossRefGoogle ScholarPubMed
Stara, P., Rizzo, R. and Tanca, G.A. (1996) Iglesiente e Arburese. Miniere e Minerali. Vol. I. (AMS, AMD, GMA Cagliari, APM, MTM Torino, CMV Varese, AMF Firenze, GMPP Piacenza, GMC Cremona and GML Milano, eds), 240 pp.Google Scholar
Stumm, W. and Morgan, J.J. (1996) Aquatic Chemistry. (Schnoor, J.L. and Zehnder, A., editors). J. Wiley & Sons, New York.Google Scholar