MAC: Mines and Communities

Indonesia: The unseen threats from mining

Published by MAC on 2008-10-21
Source: Ali Munawar, Jakarta Post

The mining sector has made a very significant contribution to the Indonesian economy the past several decades and will continue to do so for decades to come. Indonesia is the seventh largest producer of
both coal and gold in the world, with productions of 169 Mt in 2006 and 120 Mt in 2007, respectively.

The overall contribution of the Indonesian mining industry to GDP in 2006 was about Rp 56 trillion or 3 percent of the total national GDP.

The mining industry is just like a coin with two different sides. On one side, it is benefiting the country by providing significant revenue and materials to sustain development. On the other side, it has generated a vast range of environmental problems. More often, however, the latter side commonly gains less attention than the first side. Public concerns regarding the environmental problems associated with the mining industry, however, have been continuously increasing in recent years.

Environmental impacts brought about by mining activities depend on the techniques employed and types of commodity to be mined. Generally speaking, surface mining generates a greater environmental impact than underground mining. Surface mining involves removing a large amount of land area and layers of rock to obtain the coal seams or ore body of minerals. This results in large amounts of overburden and rock wastes.

Mineral mines, such as copper, gold, lead, silver and zinc produce more than 90 percent of the total rock mined as waste. Most mine operations in Indonesia are surface mining; consequently, their negative impacts are large and significant. Erosion and sedimentation are the two most visible negative impacts of surface mining, resulting in decreased quality of the surrounding ecosystem. Most soils in mined lands are poor for plant growth due to low nutrient and organic matter content, compaction and contamination.

Beside such physical impacts, there is even a more serious environmental problem facing the mining industry in Indonesia today: The unseen threat of acid mine drainage (AMD). AMD, sometimes called
rock drainage, is generated when materials containing reactive sulfide minerals, most commonly pyrites (FeS2), are exposed to oxygen and water and is often accelerated with microbiological activity.

Such an oxidation reaction produces acidic water which has high sulfate and dissolved metal (including heavy metals) concentrations. AMD cannot be easily seen because this water is colorless like fresh clean water. It cannot be judged from the color.

These sulfide minerals are commonly found in the coal seams and other mineral ore bodies, overburden or rocks layers removed during mine operation, and/or in tailings of mine processes. Formation of AMD
will continuously occur as long as these sulfide minerals are present in the mine sites -- even decades or centuries after mining operations are complete.

Historical mining of the Rio Tinto ore in Spain has been a source of AMD for several decades, which has caused massive metal contamination of stream and estuary sediments. Similarly, AMD from abandoned mine sites in the Appalachian Region of the United States has damaged over 19,300 km of rivers and streams and over 730 km2 of lakes and reservoirs.

The long, controversial environmental issues of Buyat Bay, Minahasa, North Sulawesi, several years ago have also been associated with AMD impacts. Similar cases might have happened elsewhere and will continuously happen in Indonesia unless this unseen enemy is properly and seriously managed.

Therefore, mine industries as well as the government must be aware of and pay more attention to such a potential and serious threat which can damage our resources for generations to come. Law enforcement has to be consistently employed in the field, and at the same time technologies to cope with environmental problems associated with the mining industry should be developed. Close cooperation among stakeholders, such as government, industry, research institution and the community needs to be encouraged.

While the mining sector has significantly contributed to the Indonesian economy, it has also brought tremendous environmental impacts. With the increase in population and the on-going shrinkage
of forested lands, the potential environmental impacts of mining to our natural resources will be even greater. The unseen life-long threat of AMD is only one of the examples.

Unless measures of precaution are taken seriously, our children will inherit degraded resources and an environment which can potentially result in a generation with physical and mental disabilities. None of
us want that to happen!

[The writer is a lecturer at the University of Bengkulu. Currently he is a Postdoctoral Fellow of the Endeavour Research Fellowships Programme in the Centre for Mined Land Rehabilitation (CMLR), University of Queensland, Brisbane Qld, Australia and can be reached at]


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