Environmental risk of mining - Environmental Deterioration and Contamination: Problems and their Management - page 124

6.3 The Baia Mare cyanide spill
Baia Mare, located at Romania's northwestern border with Ukraine and Hungary, has
a long history of mining, especially in gold, silver, lead, zinc and copper. An Australian-
Romanian joint venture company started its operation in the area in 1998 to re-process
gold tailings from an old unlined tailings pond. The Aurul processing plant used carbon
in pulp/carbon in leach cyanidation technology whereby sodium cyanide was added for
recovery of residual gold. Figure 5.2 shows the Aurul cyanide tailings pond where the
wastes of the gold waste re-processing were disposed of and a pipeline system next to
the tailings dam. After gold and silver extraction, the remaining tailings contained total
cyanide concentrations of 400 mg/L, with free cyanide concentrations of 120 mg/L.
These tailings were pumped over a distance of 6.5 km to the new Aurul tailings pond,
lined with a plastic membrane and covering some 93 ha (Aurul Corporation tailings
dam failure, 2001). On 30 January 2000, at 22:00, there was a break in the dam
encircling the new tailings pond of Aurul Corporation. Figure 5.3 shows the breach
on the dam.
Figure 5.2 Aurul cyanide tailings pond (left) and the pipeline system next to the tailings dam (right).
Figure 5.3 Breach in the Baia Mare tailings dam (Mihaila& Starr, 2013).