Reclamation/Revegetation

www.fcx.com

 Freeport-McMoRan Copper & Gold
Reclamation and Revegetation
PT Freeport Indonesia is committed to reclaiming or revegetating disturbed land when it is no longer used for our operations. We have conducted comprehensive reclamation studies and programs for many years in both the highlands and the lowlands areas to provide sound, scientific data to provide alternatives for reclamation of disturbed land.

Reclamation testing shows success for many species on tailings; overburden testing, utilizing only native species, is more difficult due to high altitude conditions, but successes continue to increase.

Data is cumulative 1995 through 2004.
Highlands

The highland ecosystem is shaped by environmental extremes that include very low nocturnal temperatures, high solar radiation during the day but with short periods of photosynthesis, heavy fog, high rainfalls and poor soils. Plants growing there are highly specialized, having evolved to survive in these harsh conditions. International scientific experts and PT Freeport Indonesia staff have studied the ecology of the alpine ecosystem in our work area and have developed methods to reliably produce planting stock for native species. Studies undertaken to date include: ethno-botany, biodiversity of the sub-alpine and alpine ecosystems, the use of moss for pioneering reclamation strategies and tissue culture for propagating native alpine plants. Although final closure of the overburden areas is decades away, we are committed to reclaim areas of overburden each year as they become available, monitoring the performance of various planting techniques and modifying programs to enhance their long-term success.

Through year-end 2004, more than 69 hectares of disturbed land at the mine have been revegetated to comply with PT Freeport Indonesia's commitment to the Government of Indonesia. Most of the disturbed areas in the highlands remain in active use and therefore are not yet available for revegetation. The intensive studies in the past have identified the types of native highlands plant species that do well in reclamation, while current research is designed to learn how to help improve survival of these species in the harsh conditions. Therefore, highlands reclamation in 2004 focused on the implementation of recommendations from previous studies. Native bacteria were used to enhance moss establishment at the final placement areas of overburden. Tissue culture techniques and conventional cutting methods were used to develop large-scale propagation that successfully resulted in a 95 percent survival rate of 135,000 propagated plants, comprising more than 20 species of native alpine plants.
 

Mangrove seedlings propagated in
PT Freeport Indonesia nurseries are used in assisted colonization programs in the estuarine portion of the tailings management area.
Lowlands

In the lowlands, reclamation research has repeatedly demonstrated that native species successfully colonize naturally and grow on soils containing tailings. Soils containing tailings are very suitable for growing many agricultural crops when the soils are ameliorated with organic carbon. The objective of PT Freeport Indonesia's reclamation and revegetation program in the lowlands is to transform the tailings deposits in the Modified Deposition Area into agricultural or other productive land use or to return it to native vegetation after mining is completed. Cumulatively through the end of 2004, 126 plant species have been successfully planted on soils containing tailings. Some plant species that were successfully tested to date include legume cover crops for fodder; local trees such as Casuarina, and matoa; agriculture crop plants such as pineapple, melon, and banana; and, vegetables and grains such as chili peppers, cucumbers, tomatoes, rice, string beans and pumpkins.

Harvests of edible plants and fruit from many of these species were conducted in 2004. A total of 281 samples from 58 edible plants and fruit were collected during the year for metals-uptake analysis. PT Freeport Indonesia's comprehensive sampling program monitors environmental conditions in the tailings deposition area. Rigorous testing performed on these edible plants and fruits continues to indicate that metals uptake from the minerals naturally contained in the tailings is minimal and levels remain well below the maximum allowable levels stipulated in national and international standards for these plants.

PT Freeport Indonesia conducted its reclamation plan based on the PT Freeport Indonesia RKL-RPL (Environmental Management and Monitoring) work plans, which are submitted annually to the Government of Indonesia. A total of 60 hectares of tailings deposition area were reclaimed by the end of 2004. Some 8,500 fastgrowing species were planted in 2004 in the tailings deposition area, consisting of Sesbania grandiflora, Caliandra surinamensis, Gliricida sapium, Paraserinates falcataria, Leucaena leucocepala, and Enterolobium cyclocarpum. This was followed by the planting of 1,000 coconut trees, 900 plants of various native tree species, and 1,500 Casuarina trees. Monitoring of the growth of these trees continues to indicate excellent progress. An animal husbandry program has been developed in the lowlands to demonstrate that cattle can be raised and grazed on deposited tailings. This project was established in cooperation with the local government to monitor cattle health. Through December 2004, a total of 110 head of cattle were raised in this area.
 

More than 50,000 mangrove seedlings were planted in 2004 on 25 hectares in the estuarine portion of the tailings management area.
Two types of legume cover crops (Colopogonium muconoides and Centrosema pubescens) were planted in 2003 to be used as biomass to accelerate formation of soils in five hectares of the tailings area in 2004. The legumes are also nitrogen-fixers that add nutrients to the soils containing tailings. In addition to the production of commercial crops, another strategy of tailings reclamation is to encourage natural ecological succession (the natural regrowth of native species) in designated areas. Natural succession occurs quickly in many parts of the deposition area, led by Phragmites karka grass. The Phragmites grass produces detrital biomass which enriches soils containing tailings. This process also improves water retention capacity of the soils so that other species can propagate.

An independent research project completed in late 2002 on natural succession of vegetation on tailings in an area outside the current deposition area, but which previously received tailings, found that in a period of only a few years, 264 plant species have naturally re-colonized and are growing well. This aspect of tailings reclamation has been observed and studied by PT Freeport Indonesia for years, but the formal confirmation and documentation of this process by independent scientists is significant.

A portion of the tailings pass through the Modified Deposition Area. Some of the newly formed lands from these sediments have been naturally colonized by mangroves. Within the past several years, six mangrove species, 30 species of crabs and shrimp, four species of snails and several species of fish and marine polychaetes (worms) were identified in the mangrove colonization areas. To accelerate the primary succession process in these newly formed lands, PT Freeport Indonesia initiated an assisted mangrove colonization program in April 2002. A total of 50,000 mangrove seedlings were planted in 2004 on 25 hectares utilizing contractors from the Kamoro people, the traditional lowlands inhabitants. Monitoring of the survival rate of mangrove seedlings that were planted showed that the growth and survival rates of the planted seedlings are similar to rates reported for other assisted colonization programs from around the world described in scientific literature. The mangrove swamplands are part of the native ecosystem and provide a protective barrier for inland residents.
 

Reclamation development activities in the tailings deposition area include establishment of forest plants (background), fruit trees (foreground), animal husbandry and aquaculture.
Freeport's Green Team:
A Mission to Grow
On approach to the Timika Airport, aircraft passengers looking from their windows see a wide sandy delta with various braided streams just to the east of the airport. The gray sand lies in contrast to the green forest to the east and the colorful rooftops of Timika to the west. It looks not unlike many of the major rivers which carry enormous sediment loads from the high mountains of central Papua. What makes this sandy plain different is that it is bordered by levees to the east and west - levees constructed by PT Freeport Indonesia as part of a program to control the placement of tailings sand from the milling of ore from the mining operation. The plot is called the Modified Deposition Area, an area currently encompassing 14,600 hectares, designated by the Indonesian government for the placement of the sand called tailings.

Tailings is nothing more than crushed rock - silica, limestone and other natural sediment that remains after the economically recoverable minerals containing copper, gold and silver are physically separated in Freeport's mill in the highlands. There are no harsh chemicals, no cyanide, nor heavy metals such as mercury or arsenic in levels higher than natural background. There is more tailings sand, however, than product at the end of the milling process.
 

Matoa trees, bearing a popular indigenous fruit, thrive in the Modified Deposition Area, as part of the reclamation development program.
Managing this volume of tailings is one of the important aspects of PT Freeport Indonesia’s environmental programs. There is no room in the narrow valleys in the highlands near the mill to store the sand, so the Indonesian government approved the use of a river system to transport the sand to the Modified Deposition Area in the lowlands.

The deposition area is not all gray. Upon closer inspection from the air, one can see areas of green amid sand. Vast expanses of natural grasses, shrubs and trees have taken root in dry areas in a process of natural succession. In one study plot, more than 100 plant species have appeared over a period of a few years. Dozens of bird species and other wildlife have made these green stretches home. PT Freeport Indonesia has constructed a bird blind in one marsh, enabling employees and local residents a vantage point to view local wildlife.

In some grassy portions, cattle graze. In small ponds, tilapia fish are being tended. In manicured plots, agricultural crops - pineapples, matoa fruit, sago palm, tomatoes and chili peppers - are being harvested. All these zones provide a snapshot of the potential of the Modified Deposition Area in the future. When mining is complete, the entire area will be revegetated or reclaimed. Mining will continue for several decades at Grasberg and surrounding deposits in the mountains. But it is not too early to begin the process of reclamation in the lowlands.

Yahya Alkatiri (right) and Yahya Husin survey the growth rate of Casuarina trees in a 100-hectare plot inside the Modified Deposition Area. The growth rate has been enhanced by planting legumes, which introduce nitrogen to the tailings soil.
Yahya Alkatiri walks a tour group through what appears to be a coniferous forest with pine trees growing in excess of five meters high in a 100-hectare plot inside the deposition area. A horticulturist who first planted the Casuarina trees on this plot four years ago, he is keenly interested in the growth rate since his team began a program of row-planting legumes beneath the tall trees to provide added nitrogen to the sandy soil. The trees were planted on 100 percent tailings sediment that is approximately 3-meters deep in an area of the Modified Deposition Area that became available for reclamation following the construction of a new levee. "The legumes - a variety of clover in this case - are helping a lot. These
trees are very healthy," Alkatiri says, stooping to dig a handful of soil. "This is all tailings from the mill, but if you look at it, it is now taking on the look of rich soil because of the way we've naturally conditioned it with a combination of the legumes and also manure from the cattle that are grazing nearby," he adds.

The cattle, shipped in from Australia on the hoof, appear to be at home - they eat silage made up of shredded grasses from the deposition area, mixed with molasses and grains. They have become a critical part of the balance of building soil in the area, organic material required for sustained plant growth.

Alkatiri is part of PT Freeport Indonesia's Agricultural Task Force, a unit of agricultural, soil and animal husbandry specialists created to spearhead a major effort to demonstrate how the deposition area might be used as productive land at the end of mining. It will ultimately be up to the local community and the government to decide how to use this land.

"For now," Alkatiri adds, "we're providing a range of options - from forestry and timber crops, to local food plants like sago and matoa, to aquaculture," he says. The Task Force project is a demonstration project at this point, but there are already fruits of their labor. Food crops grown here are sold in local markets and served in company dining halls.
 

Livestock have become a critical part of the balance of building soil in reclamation plots inside the tailings deposition area.

 
Back to Top