Fig. 4.

Responses of sulfate and chloride concentrations in pore water of Cu-tailings subject to organic matter remediation: 10 and 20 % hay (v/v). The hay was mixed thoroughly throughout the profile of about 100 cm in a large plastic container (1 × 1 × 1 m). The containers were situated on a tailings storage facility under field conditions (Huang et al., 2011a). The leachate solutions were collected by using ceramic suction cups placed horizontally at 15 and 80 cm below the surface under a maximum pressure of 400 Pa. The data were pooled from the results over a period of 12 months.