Environmental perspective of Ok Tedi gold, copper mine

ENVIRONMENT

OK Tedi Mine is located in an extremely remote and rugged part of Papua New Guinea.
It is situated at an altitude of approximately 2,000 meters above sea level in an area covered with a dense rainforest with an annual rainfall averaging 9 millimeters (mm) per year.
It is an open-pit copper and gold mine located near the headwaters of Ok Tedi river in the Star Mountains in the North Fly District of the Western Province. It is one of the oldest mines and has been operations for over 30 years. It began commercial production in 1980s and has been an economically important mine to the Government of Papua New Guinea. The mine exports its copper and gold at the international markets and also within the country.
Like every other mine in Papua New Guinea as well as in other countries, Ok Tedi has seen a significant environmental impacts since its beginning in the early 1980s. The environmental impacts are influenced by the high rainfall and highly unstable landforms of the mine area. The high rainfall and geotechnical hazards of fractured and friable siltstone with limestone outcrops are easily eroded and wasted away resulting in landslides that end up with debris at the riverine system. These vulnerabilities and hazards have major construction, operational and environmental challenges since its mining operations in 1984.
Economic impacts and benefits The mine has brought about economic and social benefits to the landowners and also to the Government of Papua New Guinea. It has provided monitory benefits, employment opportunities and social welfare facilities like healthcare and educational infrastructure.
Let us analyze some of the works during those early years of developments and the associated environmental issues. In mining the major source of environmental issues are related to tailings and waste rocks generation and disposal.

Tailings
Tailings are byproducts or waste stream produced after the ore bearing rocks are crushed and processed to recover desired minerals. They are left over waste material from the processing of mined ore. They are a slimy mixture of rock particles, which consists of uneconomical metals, chemicals, organic matter and effluents from the process used to extract desired mineral from the ore.

Waste rocks
Waste rocks are heterogeneous materials that are to be removed to reach the ore body or ore. The ore is than removed, crushed and refined using various processing and enrichment methods to extract desired metals and or minerals. Waste rocks are also referred to as overburden wastes produced during ground preparatory works.

Environmental impacts
The OK Tedi gold and copper mine is an open cut mine also referred to as open pit mine. The operations involve digging, blasting, shoveling, and transporting, stockpiling, crushing and processing and refining and milling.
The environmental impacts of the Ok Tedi Mine have been a topic of concern due to its large-scale mining operations. Here are some of the key environmental effects associated with the mine:

Environmental issues
The mine has also brought about environmental issues beside its benefits. The mine originally had a plan to construct a tailings and a waste rock dump to retain much of the waste produced from the mine during its entire life. There is a difference between these wastes, tailing are generated from milling and processing of ore while waste rocks are produced primary from digging and crushing from all works.
During the construction of the tailings dam at Ok Ma in 1984, a landslide occurred flooding the whole area. The works could not continue and the Government gave an approval for an Interim Tailings Storage facility (ITS) for the storage of tailings. The ITS was than constructed and used for containment of tailings until it outran its designed holding capacity in 1986 leading yet to another Government approval for Ok Tedi Mining Limited to discharge directly to tailings into nearby creeks that eventually flowing into the larger OK Tedi and Fly Rivers. At the same time, the waste rocks were also being disposed into Sulphide and Harvey Creeks that also flows into larger Ok Tedi and Fly Rivers.
In 1989, the northern failing wastes rock dump constructed in the upper reaches of Sulphide Creek was destroyed by a landslide and the State gave approval to OTML to continue using failing dump wastes to discharge into northern sulphide creek and southern Harvey creek/Ok Mani of the pit.
Since then, mine wastes is being disposed into the two tributaries of Ok Tedi, the Sulphide Creek that connects to Ok Gilor and then the Ok Mabiong before entering into upper Ok Tedi and Harvey Creek which joins the Ok Mani before it enters Ok Tedi at Tabubil.
The continuous discharge of tailings and waste rocks significantly increased the sediment load thereby raising the river bed making river transportation difficult. Approximately 40 million tons of waste rock and 30 million tons of tailings are discharge annually into the river systems. Waste rocks consist of coarse material and 60 percent of that breaks down during movement into finer or smaller material in the sand-silt sizes.
The direct discharge of tailings and waste rocks into the river systems continues to be the most significant long-term challenge to the management of Ok Tedi Mining Limited (OTML). The discharge of these waste streams have adversely impacted the Ok Tedi and Fly River system affecting aquatic as well as terrestrial ecosystems and the livelihoods of communities along these river corridors.

Impacts on Communities
Some estimated 30,000 people living along southern site of Ok Tedi and Fly Rivers have been adversely affected by the mines environmental impacts. People along these river systems are no longer able to sell their fish and garden produce due to the polluting effects from the mining activities.
The major mining impacts have been related to onshore and river bed sedimentation resulting in rising river bed making river transportation difficult, water pollution (water quality impacts), flooding frequencies and intensity, vegetation dieback and negative impacts on the river line communities.
Environmental management efforts by Ok Tedi Mining Limited to minimize, mitigate and remediate damages continue with the biggest challenge to long-lasting solutions.

Environmental monitoring
The monitoring and environmental management is a requirement by the state for the operations of the mine. The OTML has an Environmental Team consisting of environmental scientists and technicians who are responsible for the monitoring of the past and present impacts of the mine activities along the 1,000 km downstream riverine system from the main mine site to the Fly River Delta.
This includes maintaining hydrological network of monitoring stations along the river system, regular field sampling of water, sediment, food, vegetation surveys, data analysis and reporting. The OTML Environmental Team works closely with the Community Relations Team proving environmental information to stakeholders’ consultation. The data is also reported to the Sate in Annual Reports.
The environmental department also works on programs in readiness for mine closure and has established a nursery and re-vegetation trails on a number of the Bige stockpiles.

Deforestation and habitat destruction
The mine preparatory works and operations have resulted in a significant removal of forest cover (deforestation). Large areas of vegetation including trees have been cleared to cater for mining infrastructure, roads, accommodation, processing plants, offices, support infrastructure and waste disposal sites. The forest removal inevitably leads to habitant destruction affecting wildlife and ecosystems. The removal of vegetation has also created increase soil erosion and water pollution and stream bed sedimentation.
Water pollution
Mining activities generates large volumes of contaminated wastewater containing heavy metals such as copper, lead and zinc and other pollutants. These contaminants enter the nearby rivers and streams through leaching effects and impact the aquatic ecosystem and impact water quality. Sewage wastewater is another source of water pollution if not managed properly. The Ok Tedi River has this particular pollution problem.

Acid mine drainage
This is caused when sulfide minerals in the ore are exposed to air and water from stockpiles of ore and rocks reacting to form acidic solutions. The acid mine drainage can contaminate water sources and harm aquatic organisms.

Health Impacts
Exposure to the release and presence of heavy metal contamination and exposure to other pollutants can have adverse effects on human health.
Local communities living in and around the mine is exposed to contaminated water, soil, fish and other aquatic source of food creating health issues such as skin diseases, gastrointestinal impairment and long term toxicological effects. Water borne disease and long term health effects and lack of proper waste management and sanitation facilities are having raised health challenges to the Management of OTML.

Community development and compensation
As part of the development agreement with OTML, the Government of Papua New Guinea and the local communities, OTML has implemented community development programs, and is paying compensation to affected communities. However, there have been issues and criticisms regarding the adequacy and fairness of compensation as well as effectiveness of development indicatives.
Efforts have been made to diversify local livelihoods to sustain themselves beyong mining. Community development efforts focus on education, health and sustainle agriculture.
There are continuous dialogues and collaborations with local communities, government agencies and NGOs to address issues and concerns. Transiency is exercise at all stages to share information about environmental performance and mitigation efforts.
Rehabilitation and reforestation
Reforestation programs are being implemented to restore degraded forest due to mining activities. Native tree species are being propagated to stabilize soil, prevent erosion and promote biodiversity.
OTML operations are governed by a legislative framework to ensure that the mining impacts are regulated and impacts minimized. Compliance with environmental standards is monitored and faults are identified and penalties imposed for violations penalized

Life after mine closure
OTML, as required by the regulatory framework by the Government of Papua New Guinea, has mine closure plans. Theseare important for post-mining land use, rehabilitation and ongoing monitoring to identify impacts after the mine closes.
This is to ensure that the mine site remains safe and stable for use by the communities after the mine life comes to an end.