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Tuesday October 2, 2007

Poisonous wasteland


The Mamut copper mine in Sabah has left a toxic legacy.  

THE towering Kinabalu plateau beckons visitors from the world over and is a source of pride for Sabah. But on the south-eastern flank of the country’s first World Heritage Site lies a wasteland so poisonous that the state government has avoided speaking about until recently. 

Mamut copper mine – the first open-cast mine in the country – began churning out copper ore in 1975. Throughout its peak production years, and up until 1994, the annual production of copper concentrate was 100,000 tonnes or 25,000 tonnes of pure copper.  

Over its lifespan, the mine earned an export revenue of about RM3.4bil. Seventy percent of the revenue was contributed by copper while gold and silver accounted for 27% and 3% respectively. The metal ores were processed on-site to produce copper concentrates that were shipped mainly to Japan. 

Don’t drink: Acid mine drainage from the waste in the Mamut mine pit oozes into a collection pond that eventually flows into Sungai Mamut. – Picture by Dr FELIX TONGKUL
Started as Overseas Mineral Resources Development Sabah Sdn Bhd, the Japanese-Malaysian joint-venture project was subsequently sold to Mega First Bhd in 1991 and renamed Mamut Copper Mining Sdn Bhd (MCM).  

Acknowledging the toxic legacy left behind by the 24-year mining operation in the district of Ranau, state Tourism, Culture and Environment minister Datuk Masidi Manjun has called for concrete rehabilitation plans before talks of any development projects. 

Upon its closure in 1999, grand plans were announced: world-class university, organic farm and tourism resort. One by one, the ideas died a natural death. The site is an ecological nightmare with residual impact that continues to pollute waterways, coupled with threats of landslides at the mined pit.  

Typical of open-cast mines, Mamut generated large volumes of solid wastes consisting of overburden materials (8%), waste rocks (50%) and tailings (42%). The overburden materials and waste rocks were dumped at four main dump sites near the mine pit. Some 150 million tonnes of tailings, by-products from the metal ore extraction process, were piped over a distance of 16km to a tailing dam sited in Lohan Valley about 980m below the mine.  

Foul waste 

Assoc Prof Dr Marcus Jopony of Universiti Malaysia Sabah (UMS) said the operation, particularly in its early years, had degraded water quality and silted up agricultural land. The geo-chemist said silt materials were washed from the mine and waste dumps into the Mamut, Lohan and Bambangan rivers, affecting water use and aquatic life. 

In 1975, the tailing pipe system leaked tailing slurries into some 800ha of paddy fields in the valley. Overburden materials and waste rocks were washed into Sungai Lohan in 1977, affecting agricultural land along river banks. 

The 400ha tailing dam was a constant source of dust pollution to surrounding areas, especially nearby Kampung Bongkud. The company planted grasses, legumes and Acacia trees to provide vegetative cover. A network of sprinklers was installed along the dam perimeter and water trucks were deployed during extended drought. Mitigation measures like slope stabilisation and rehabilitation were taken to minimise run-offs from waste dumps. However, remedial actions were insufficient and stopped completely after the operation ceased. 

As expected, acid mine drainage (AMD, highly acidic, metal-contaminated leachate, emerged as the most prominent pollution in the post-mining phase. Water quality data collected over the years indicated AMD pollution of rivers.  

“Recent studies have ascertained that AMD is being discharged from most of the waste dumps at the pit area. This AMD ultimately enter surrounding rivers without prior treatment. Currently, Sungai Bambangan is the most adversely affected. The river has a consistently high acidity of pH4.5 and an elevated concentration of dissolved metals. The bottom sediments and rock surfaces are also covered with silt-like materials – metal precipitates formed during mixing of AMD with river water,” wrote Jopony and his colleague, geologist Dr Felix Tongkul, in a paper titled Economic and Environmental Impacts of Mining in Mamut: Lessons Learnt and Future Challenges. 

The 1.5km-deep pit left behind by mining now acts as a generator as well as a collector of AMD, turning it into a huge reservoir of acidic water. 

In an interview, Tongkul said as recent as June, he recorded increasing landslides in the pit area. 

“There are a lot of indications that the pit wall is unstable. The worry now is over the volume of soil falling into this huge pool of water in the pit. In the worst case scenario, it might create a huge splash that would have a forceful spill-over on nearby areas like Poring Hot Spring,” cautioned the geologist.  

Due to lack of maintenance and discontinuation of remedial work after the closure, some slopes at the dump sites are deteriorating. Some slopes that have not been rehabilitated are more prone to erosion. 

Environmental liability 

The undesirable legacy of Mamut is an expensive lesson. So far, the state government has allocated RM13mil to rehabilitate the abandoned pit, tailing dam and surrounding areas. 

Jopony said MCM operated during the period when legislative standards for environmental protection were not in place. Although legislations on environmental impact was enacted 12 years before the mine closure, it was not enforced on the mining operation. Consequently, added Jopony, there has been no official documentation of the impact and mitigation measures. 

It was not until 1994 that the Federal Mineral Development Act was enacted. This Act included legal requirements to be observed by mine operators before, during and after the commencement of mining activities. The new law includes provision for the rehabilitation of mining land and establishment of a Mine Rehabilitation Fund. 

However, the Act was only adopted by Sabah in the form of the State Mineral Enactment 1999, after the closure of the mine. Therefore, MCM is not legally obliged to undertake post-mining rehabilitation or to contribute to the fund. 

“As a consequence of the legal limitation, the closed mine is becoming a liability to the government. Environmental remediation will involve considerable expenses. This is a lesson that we must not forget,” said Jopony, adding that the announced allocation would be insufficient. 

“No doubt the project created jobs but the irreparable effects to the environment is catastrophic. Many rivers are polluted and the land cannot be tilled. It will be years before the whole area can be classified as safe. Future projects must clearly adhere to conditions,” said Masidi. 

The state government received a royalty payment averaging 10% between 1975 and 1987 but the rate was revised to a flat rate of 2.5% for the period from 1988 to 1999. The total royalty payment amounted to RM200mil. 

When asked about Mega First’s intention to renew mining in the same region, Masidi said: “My personal opinion is that we should think of other development projects other than mining.” 

The company declined to comment on problems in the post-mining phase. 

The UMS scientists said AMD can be neutralised by treating the contaminated soil with locally available limestone and serpentine rocks. Until that happens, the turquoise-coloured pit will remain an ugly wound in the country’s environmental record.  

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