Waste Management Outlook for Mountain Regions

CASE STUDY

WASTE GENERATION AT OK TEDI MINE

OkTedi Mine, Papua NewGuinea

OK TEDI MINE ENVIRONMENTAL DISASTER

The Ok Tedi mine, one of the largest copper mines in the world, demonstrates the difficulty of waste management in mountain environments and the impact mine waste can have on downstream people and ecosystems. The Ok Tedi mine is located high in the Star Mountains of western Papua New Guinea. The area is subject to extreme rainfall (exceeding 10 m/ yr) and is in an active seismic zone (Eagle and Higgins, 1991). A tailings dam was originally planned for the mine, but during the construction phase in the late 1980’s, it collapsed and the company was given permission to go ahead with an alternate waste management plan. A crude, low-cost option consisting of erodible dumps was employed – essentially waste is dumped on steep slopes designed to erode into the headwaters of the Ok Tedi River, a tributary of the Fly River. The annual discharge into the Fly River is estimated to about 65 million tons per year (OTML, 2014). This increased sediment load has had a major impact on downstream communities, severely affecting the riverine and flood plain environment. It has raised the riverbed, in places dangerously accelerating currents and caused extensive areas of forest dieback due to sedimentation in the flood plain (Baker 1999). Ok tedi Mining limited, the operators of the mine, have estimated the dieback area could eventually be 3000 km 2 (Van Zyl et al 2002). It is thought that more than 30,000 people have been directly impacted by the mines’ operations (Banks, 2001). Elevated levels of copper (highly toxic to many aquatic organisms) have been implicated in the decrease in fish stocks in the river (Swales et al 1998). Increased levels of copper and other mine derived contaminants have been detected in the Fly River Delta more than 1000 km downstream from the mine (Baker, 1999). The potential long-term consequences of the waste disposal strategy, including any future provision for cleanup, were amajor factor in the decision of the original owners of themine to depart in 2002. The mine is now owned by the PNG government (OTML, 2016) and the people of Papua New Guinea have inherited sole responsibility for the waste problem. A fund has been set up (the Ok Tedi Foundation) to provide long term development assistance and compensation to the villages impacted by the mine (WRI, 2003).

STAR MOUNTAINS

TAILINGS DISCHARGED TO RIVER

Ok Tedi mine (1600m)

megatonnes

10 15 20 25 30

Tabubil

0 5

Ningerum

Ok Tedi

Mine tailings raising the sediment load and river bed

1984

1989

1994

1999

2004

2009

2014

INDONESIA

WASTE ROCK DISCHARGED TO RIVER

Kiunga

Atkamba

megatonnes

10 15 20 25 30 35 40 45 50 55 60

Fly River

Nukumba

PAPUA NEW GUINEA

Fly River

Lake Murray

0 5

Bosset

1984

1989

1994

1999

2004

2009

2014

COPPER CONTAINED IN DISCHARGED WASTE

Town Village Dieback extent

120 1000s of tonnes

Ogwa

Obo

100

80

60

Ok Tedi

40

20 km

INDONESIA

PAPUA NEW GUINEA

20

AUSTRALIA

0

Source: Ok Tedi Mine Limited, http://www.oktedi.com/

1984

1989

1994

1999

2004

2009

2014

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