Hazardous mineral waste has been geochemically treated before storage in a Central Disposal Site of the remediated abandoned Baccu Locci lead-arsenic sulfide mine (Villaputzu-San Vito, Sardinia, Italy)
Summary
Coarse mining waste rock occurs against steep valley walls at the exit of mining galleries of the abandoned Baccu Locci mining area. Finer-grained mining waste rock and tailings occur downstream at the former ore processing plant and along the braided Baccu Locci River. Toxic heavy metals and arsenic pollute river- and groundwater.
On behalf of the municipalities of Villaputzu and San Vito, Montana SpA designs an impermeable Central Disposal Site for safety storage of a total of approximately 60.000 tons of strongly contaminating solid mineral waste. Integra Srl is responsible for construction of the disposal site and the execution of the remediation works. GeoChemTec developed a geochemical technology for the treatment of the waste. While draglines excavate the mineral waste from the many small deposits within the valley of River Baccu Locci, GeoChemTec takes samples for immediate analysis and characterization of the waste. It calculates appropriate concentrations of mineral reagents and supervises addition and active mixing to truckloads before transport and during redeposition in the central disposal site. Additionally, GeoChemTec developed and supervises the construction of a permeable reactive barrier at the foot of -, and within the Central Disposal Site, used for the pretreatment of any contaminated percolate, before it leaves the site for final treatment in external permeable reactive barriers.