Tailings Management

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 Freeport-McMoRan Copper & Gold
Tailings Management Program
Tailings are finely ground natural rock residue from the processing of mineralized ore. PT Freeport Indonesia uses a physical flotation process to separate the copper and gold-bearing minerals from the host rock. Neither mercury, cyanide nor other potentially harmful chemicals are used in the process. A dedicated river system transports the sediment to a designated deposition area in the lowlands and coastal zone, engineered and managed for the deposition and control of tailings. The tailings deposition system is operated under PT Freeport Indonesia’s comprehensive tailings management plan, approved by the Government of Indonesia during the 1997 300K AMDAL process.

As part of the government-approved AMDAL (environmental and social impact study) completed in 1997, it was agreed that the approved tailings management option should be studied in further detail. A Tailings Review Committee comprising of members of the Environmental Risk Assessment Review Panel Team, the PT Freeport Indonesia Environmental Advisory Council, and PT Freeport Indonesia management was established to review this issue. After a series of detailed studies were completed, including analysis of remote sensing information, evaluation of potential pipeline options, a review of geotechnical considerations, flood and hydrogeological impacts and comprehensive risk assessments, the Tailings Review Committee concluded that the approved tailings management system is the best option available. Independent environmental audits of PT Freeport Indonesia’s environmental management systems have reached the same conclusion. PT Freeport Indonesia continues to work with various national and international experts to ensure that its tailings management represents best practice, considering the applicable geotechnical, topographic, climatological, seismic and rainfall conditions.

A technical group — consisting of international experts and representatives of the Institute of Technology at Bandung, P.T. Puri and PT Freeport Indonesia — has reviewed our tailings management practice and developed recommendations to enhance the effectiveness of tailings retention program techniques. The tailings retention plan divides the deposition area into three sections or zones based on the elevation, sediment grain size and type of flow, and details specific techniques that may be effective in each section. These retention techniques include the use of bio-filters, permeable groins, flow deflection structures and other engineering applications. PT Freeport Indonesia is committed to maintaining a proactive management team solely dedicated to ensuring the implementation of tailings retention plans and reclamation plans executed each year. Much of the work implementing these plans is handled by local contractors, putting money into the local community and developing local business skills.

PT Freeport Indonesia also submitted in 2002 to the Government of Indonesia a detailed Environmental Risk Assessment (ERA) of the tailings management system. This assessment found that the identified environmental impacts of PT Freeport Indonesia’s tailings management system were consistent with those anticipated by the company’s comprehensive environmental and social impact study, the AMDAL. We have begun a five-year update of critical conclusions of the ERA study that should be complete in 2007.

Studies of tailings reclamation and establishment of demonstration plots on deposited tailings show that tailings can be readily revegetated/replanted with native forestry and agricultural plants. In fact, natural re-colonization takes place rapidly. When mining is completed, the tailings deposition area will be reclaimed in a manner consistent with the appropriate technique established through consultation with various stakeholders, taking into account appropriate consideration of environmental and social impacts.

Extensive sampling of water quality in the tailings management system evidences that the water in the river that transports the tailings from PT Freeport Indonesia’s mill in the highlands to the lowlands tailings deposition area meets the Indonesian and U.S. Environmental Protection Agency drinking water standards for dissolved metals. Data from biological sampling continue to demonstrate that the estuary downstream of the tailings deposition area is a functioning ecosystem based both on the number of species and the number of specimens collected of nektonic, or free-swimming, organisms such as fish and shrimp. In 2006, we commissioned an independent study of fisheries resources in the estuary impacted by tailings and adjacent estuaries. The study concluded that resources could support local needs at many times the present demand, but that there was a threat from illegal taking by foreign commercial boats working in the area.
 
Ajkwa River Channel
Beginning in 1998, a new levee was constructed to the east of the existing west levee which provided the western boundary for the tailings deposition area in the lowlands. Construction of the new levee created a channel between it and the old west levee. With approval of the Government of Indonesia, PT Freeport Indonesia completed work in 2005 on the diversion of the Ajkwa River into this channel, near the Ajkwa River’s original course. The Ajkwa diversion is performing as expected with rapid stabilization of the channel and meandering pattern development.

 


There are a number of environmental advantages to diverting the Ajkwa River from the tailings deposition area and returning it near to its original channel. Now, only the Otomona River carries the tailings sediment to the tailings deposition area. The flow of the Ajkwa previously contributed to the transportation of tailings through the land-based portion of the deposition area. Redirecting the Ajkwa River to the channel between the two levees also provide additional natural freshwater flow along the eastern boundary of the heavily populated area of Timika.

Directing the Ajkwa River flow to the new channel also allowed large-scale reclamation demonstration projects to be carried out on previously deposited tailings in the area between the two western levees. This area is now the site of successful reforestation and agriculture projects begun as the new levee was being built.
 
Tailings Show Promise as a Resource for Development
One of PT Freeport Indonesia’s most resource- and labor-intensive activities is the management of the waste product known as tailings — the finely ground natural rock residue from the processing of mineralized ore. A dedicated river system transports the non-toxic sediment to a designated deposition area in the lowlands and coastal zone of the project area. Civil and Environmental Engineers actively manage the deposition as part of a comprehensive tailings management plan approved by the Government of Indonesia.

Freeport’s environmental experts have demonstrated for years that the tailings material can be readily revegetated or reclaimed with native forestry and agricultural plants. When mining is complete, the deposition area will be valuable high ground suitable for many applications. One emerging project, however, can put the material to positive economic use in the short term.

Freeport Indonesia President–Director Armando Mahler (left) and Papuan Governor Barnabas Suebu sign a Memorandum of Understanding on a project to use tailings in construction projects throughout the province.

During the past several years, Freeport Indonesia has been collaborating with scientists from Indonesia’s leading technological research university, Institute Teknologi Bandung (ITB) — the Bandung Institute of Technology’s Research and Industrial Affiliation Institute — on tailings’ use as a raw material for the construction and manufacturing of concrete, bricks, pipes and other infrastructure products. The results so far have been promising. According to the researchers, the properties of the material are conducive to construction applications and the crushed rock offers cost advantages over other basic material. .

It is a solution that has development-minded regional government leaders expressing optimism. Papuan Governor Barnabas Suebu, upon signing a Memorandum of Understanding (MOU) with Freeport Indonesia on a landmark project to use tailings in construction projects throughout the Province, referred to tailings as a vital part of his infrastructure development concept. Governor Suebu said, “By the grace of God, there is a solution to the issue (of tailings). What has been considered a weak point has become a strong point.”
 
Governor Suebu has outlined a development plan that calls for a system of new roads linking key regions of the resource-rich province. He is calling for the use of tailings as a component of the concrete for roads, bridges and culverts. He has called for the use of five million tonnes of tailings annually in the initial stages of the project.

Freeport Indonesia has commenced work under the MOU with the Mimika Regency’s Public Works Agency to prepare a site to hold the tailings material for transport to the construction sites. Freeport and the government are cooperating in a study into possible construction of a manufacturing facility in the area.

The joint Freeport/ITB team has completed several construction projects over the past several years using tailings as a primary component of concrete. Projects include several public bridges in the Mimika Regency, sections of road in the Freeport project area, and prefabricated concrete for water treatment applications. Tailings material is also used in the construction of levees in the Modified Ajkwa Deposition Area.

Freeport Indonesia’s President–Director Armando Mahler welcomes the ongoing collaboration and sees the MOU as a “meaningful step toward materializing Papua’s development by using resources that are readily available.”
An Engineer Builds Opportunity at Home
Napoleon Sawai is a mechanical engineer whose university studies and early professional career were heavily focused on the aviation industry. Today, his feet are firmly planted on the ground — leading a 500-member team devoted to managing Freeport Indonesia’s tailings retention and reclamation projects.

One of Sawai’s first practical projects in graduate school was to eliminate air turbulence in a sensitive environment — controlling drafts in a room where computer processors and chips were being produced. His “controlled environment” has expanded from a small room to hundreds of acres of the Modified Ajkwa Deposition Area (ModADA), the engineered zone where the finely ground, non-toxic crushed rock left over from the mill process is deposited in a government-designated, managed area in the lowlands portion of the Project Area.

Sawai’s team is tasked with retaining a higher percentage of the fine sediment within the confines of the ModADA, and to find the best alternatives for reclaiming and revegetating the area when mining is complete in the future.

“I use my engineering skills, but I’m as much an educator and a salesman as I am an engineer,” says Sawai, a native Papuan who was born and raised in the provincial capital Jayapura. “We build many structures here to retain the sediment — levees, the diversion channel, weirs, groundsills and bio-filters. But we’re also building opportunities,” he says, motioning to a crew of young Papuan workers gathered for a morning safety meeting.

“These guys are so willing to learn and to accept those opportunities,” he adds, with the smile of a proud father. He says that he and the other project managers are continually learning from their “students” — the local workers — whose knowledge of local flora and fauna provide valuable input to the reclamation master plan.

The planning process is well underway for the future of the ModADA. The area will be available for many possible uses when mining is complete. “There is huge economic potential here for both agriculture and aquaculture,” says Sawai, pointing to flourishing timber stands, native matoa trees and sago palms, neat rows of cash crops, and commercial fish ponds. “But I can also envision a major sports complex — maybe a soccer stadium, and a cultural arts center,” Sawai says, summing up some of the aspirations of the local workers, “Timika is rapidly growing. It would be good to leave some of the forest intact, which we are showing is possible here. This area will be high and dry — a great space for future development.”

The 40-year-old husband and father of two received his undergraduate degree at New Mexico State University before successfully pursuing a Masters of Engineering at the University of Portland. He is proud to work “back home” in his native province in a challenging career with one of Indonesia’s leading companies. Sawai admits sometimes walking a tight-rope when it comes to hiring individuals and contractors for a growing list of ambitious reclamation and retention projects. “Sometimes it would be so easy to hire experienced people and contractors from outside the area to get things done quickly.” However, he agrees that there is much higher long-term value to be found by looking locally first. “The future depends on the local people. They need to be part of the team now as we plan together for that future.”

“We are working with many stakeholders on this project and we do have world-class experts involved,” Sawai adds. “The government agencies have their input, as do the NGOs and researchers. But the local people — especially the people who work here — have the biggest stake and they are out front and accepting that responsibility,” he explains. “I’m proud to say that my most important role here is to help build capacity.”

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