EJMP&EP





Pilot scale field performance of a reclamation scheme for sulphidic waste rock

G. Gaidajis1,*, E. Mylona2, K. Adam3, E. Gazea4

1 Department of Production Engineering & Management, Democritus University of Thrace,
University Library Building, 67100 Xanthi, Greece
2 Laboratory of Metallurgy, School of Mining and Metallurgical Engineering,
National Technical University of Athens, 157 80 Zografos, Greece
3 Environmental, Chemical & Metallurgical services (ECHMES) Ltd.,
40–42 Mikras Asias St., Athens 11527, Greece
4 Environmental Department, TVX Hellas S.A. of Mines & Gold Manufacturing,
Stratoni 630 82 Chalkidiki, Greece



Received 27 May 2003; accepted 15 March 2004




ABSTRACT

For the environmentally safe management of the sulphidic waste rock produced from the Stratoni lead–zinc sulphide mine in Greece, the effectiveness of an alternative scheme to conventional disposal methods management, involving the segregation of the –4mm sulphide rich fraction of waste rock and its amendment with the engineered application of limestone was examined. Following successful laboratory test results, pilot field tests were carried out in order to assess the performance of the above reclamation scheme and compare it with the behaviour of the “as–it–is” waste rock, i.e. increased drainage volume with acidic pH and elevated metals concentration. Based on the results of a three–year (1,114 days) monitoring programme, it was deduced that for the “as–it–is” waste rock, the amount of infiltration corresponded to 20% of the precipitation received; the leachates collected were acidic to alkaline, i.e. pH: 3.5–7.7 and mainly contaminated with Zn, Mn and Cd. The separation of the –4mm waste rock fraction and its placement above the coarse size material, reduced the overall infiltration and improved the quality of drainage collected. Homogeneous mixing of the fine waste rock fraction with limestone was recorded to further reduce the infiltration rate and resulted in the production of alkaline drainage throughout the test period. Complete inhibition of water percolation was achieved by the successive layering of the homogeneous –4mm waste rock/limestone mixture and coarse waste rock fraction, where no leachate was collected after three years of testing.


Keywords: Reclamation; Sulphidic waste rock; Drainage; Environment



* Corresponding author
   E-mail : ggaidajis@yahoo.com