Production at the giant Ok Tedi mine in the Western province is still suspended after four localised ruptures to its pyrite concentrate waste pipeline last month.
The ruptures occurred in a small section of the pipeline that runs from its tailings processing plant to underwater storage pits located at Bige.
The ruptures were mainly caused by the scouring of the pipe as the slurry travelled through the pipeline which is buried under the road. Investigations to determine the condition of the full length of the pipeline are still progressing.
As soon as the ruptures were reported, OTML took immediate steps to shut down the pipeline, however, this did not prevent some of the pyrite concentrate that was still in the pipeline spilling into the environment.
It is estimated that between 100 and 200 cubic metres of pyrite concentrate was lost through the ruptures.
A team of officers from OTML’s environment and community relations departments are working with the local communities to clean up areas affected by the spill.
Due to the steep terrain, the clean up may take several more weeks to complete.
Monitoring of these areas including the creeks and streams where the spill has entered is still ongoing.
Current results from the sampling and monitoring program has indicated that while the bulk of the pyrite remains close to the points of rupture, some pyrite is visible in streams up to 2km downstream of the ruptures.
All efforts are being made to trap and remove pyrite concentrate in the affected streams.
Water monitoring to date shows that apart from an initial flush of process water during the rupture, the water quality of the impacted streams has not been affected.
Water samples collected downstream of the pyrite ruptures indicate that the water is safe to use.
Pyrite is a natural mineral containing both iron and sulphur and is commonly found in rocks, especially those that contain valuable metals like gold or copper.
Pyrite can be potentially harmful to the environment because on exposure to air and water it can slowly produce acid.
Results from monitoring of the impacted streams to date shows no evidence of acidification occurring, however, monitoring will be ongoing both during and after the spill cleanup.
OTML managing director, Nigel Parker has said that everything possible was being done to ensure the communities were not affected by the spill “and we will be communicating to the communities the results of the environmental assays for water quality”.
Parker added that OTML had had discussions with the impacted communities and the State on its plans to recommence production while the pipeline was being repaired but said the decision to recommence production must have approval from the communities and the state.
Meanwhile, the company refutes claims of local communities being affected by the spills.
Parker stated that officers from the OTML community relations and environment departments were monitoring the situation on a daily basis and there had been no such incidents reported.
OTML is a 100% PNG-owned company and in 2010 it contributed 18% to PNG’s gross domestic product and 32% in export earnings.