TOLUKUMA GOLD MINE: BIOPHYSICAL IMPACT CAUSED BY SODIUM CYANIDE SPILL IN PAPUA NEW GUINEA

Kirpal Singh* and Frank Griffin**
Discipline of Chemistry, School of Natural and Physical Sciences
University of Papua New Guinea
PAPUA NEW GUINEA

Durban Roodepoort Deep’s Tolukuma gold mine, 100km north of Port Moresby , may be the smallest of PNG’s mining operations, but in recent times it has become the country’s most active explorer. The DRD has significantly bolstered Tolukuma’s exploration expenditure with an aim of attaining production of at least 200,000 ounces annually. Given the geographical location of the mine, all the personnel and materials are transported entirely by helicopters.

 On 21 March 2000 a 1-tonne crate of sodium cyanide pellets accidentally dropped from a helicopter sling load on its routine cargo run from its Veimauri Base Camp to the Tolukuma Gold mine. The cyanide crater hit the ground and penetrated the ground 1.0-1.5 metres in a remote forest vegetation area near Silobe creek about 12 km from Yalogei village. The crater broke up leaving some 30 percent of the mass in one lump at the site of the impact and the remaining 70 percent spread over an area of 50 square metres around the impact site. The life of people living around this area was impacted by the spill.

The TGM management organised a search, recover and clean up operation with the following strategy:

• Finding the dropped Cyanide load.
• Containment of the cyanide at the impact site.
• Recovery of free cyanide and its removal back to the mine site.
• Detoxification of residual cyanide by ferrous sulphate at the impact site.
• Monitoring of cyanide in water and soil after completion of residual decontamination.

We reviewed all the available reports by various consultants involved in order to come up with a Bio-physical Impact Study of the Cyanide Spill with the following conclusions:

• The accident was caused by poor management and unsatisfactory practices on the part of both TGM and helicopter contractor, Hevi Lift (PNG).
• The cyanide levels in water creek were well below the acceptable levels and that suggested that the treat to human and aquatic life was negligible. The high dilution factor (1:4000) was cause for low cyanide levels.
• Social implications of the cyanide spill among the members of the affected community were marked by their nervousness arising from this spill.
• On our visit to the site of incident, we were satisfied with the detoxification and extent of removal of contaminated soil from the impact site by TGM. This coupled with the natural degradation of residual cyanide in soil has helped in containment of the spill to such levels that pose no danger to humans and environment.

*Kirpal Singh ** Frank Griffin (Dr.)
Professor of Chemistry Lecturer in Chemistry
K.Singh@upng.ac.pg
Keywords: mining, exploration, extraction, detoxification, decontamination