Permeable Reactive Barriers of high efficiency have been developed for the treatment of acid mine- and rock drainage of the remediated abandoned lead-arsenic sulfide mine of Baccu Locci (Villaputzu-San Vito, Sardinia, Italy)


At the remediated mining site of Baccu Locci, Acid Mine Drainage flows from a former mining gallery and Acid Rock Drainage percolates from a newly constructed central disposal site, containing excavated and re-deposited mineral mining waste. The acid mining wastewater contains metal ions at toxic concentrations of tens to hundreds of milligrams per liter, requiring treatment before discharge into River Baccu Locci.

For the steep river valley in the remote mountainous area with semi-arid Mediterranean climate, passive treatment by means of filtration with a compact permeable barrier is required. Montana SpA designs and Integra Srl constructs two installations for an innovative porous mineral granule, developed by GeoChemTec. While supervising the application we successfully demonstrate the efficient immobilization of metals and the effective decrease of concentrations below Italian legal limits for discharge on surface water.


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)


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.