Tailings as a source of environmental pollution

The poorly recultivated tailings at the R. Ore Mines Co. site also contain large amounts of pyrite. Owing to oxidation and acidification processes tri ggered by oxygen-saturated acid rain, heavy metals are transported by the l eachate via the groundwater to surface streams of high buffering capacity w here the metals are precipitated within a brief period of time. The recipie nt Paradi Tarna is contaminated indirectly over the tributary Bikk stream. The solid metal compounds bonded to iron(III) hydroxide settle out over a s hort distance (a few km) in the bed of the Paradi Tarna. At times of low an d medium streamflow the heavy metals impose no restriction on the use of Pa radi Tarna water for irrigation. However, flood waves caused by periodic re leases of temporarily stored mine drainage water, or by major rains stir up the, metal contaminated bottom sediment and transport it to the lower stre am sections. In these periods the Paradi Tarna is unfit for irrigation. (C) 1999 Published by Elsevier Science Ltd on behalf of the IAWQ. All rights r eserved.