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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).
INDONESIA
PAPUA
NEW GUINEA
STAR MOUNTAINS
PAPUA
NEW GUINEA
Ok Tedi
INDONESIA
AUSTRALIA
Source: Ok Tedi Mine Limited,
http://www.oktedi.com/Ok Tedi mine
(1600m)
Tabubil
Ningerum
Kiunga
Atkamba
Bosset
Obo
Ogwa
Nukumba
20 km
Town
Village
Dieback extent
Mine tailings raising
the sediment load
and river bed
1984
1989
1994
1999
2004
2009
2014
1984
1989
1994
1999
2004
2009
2014
1984
1989
1994
1999
2004
2009
2014
0
5
10
15
20
25
30
0
5
10
15
20
25
30
35
40
45
50
55
60
0
20
40
60
80
100
120
1000s of tonnes
megatonnes
megatonnes
Lake Murray
Fly River
Fly River
Ok Tedi
WASTE
GENERATION AT
OK TEDI MINE
TAILINGS
DISCHARGED
TO RIVER
WASTE ROCK
DISCHARGED
TO RIVER
COPPER CONTAINED
IN DISCHARGED WASTE
OK TEDI MINE
ENVIRONMENTAL DISASTER
CASE STUDY
OkTedi Mine, Papua NewGuinea