Can the degraded land of the Amazon rainforest be salvaged by large-scale landscape restoration? Is it really possible to rebuild ecological integrity and enhance the lives of local communities in a sustainable way?
Mineraçaõ Rio do Norte’s Trombetas mine in Brazil produces 18 million mt/y of bauxite. The company supports a wide-ranging program to restore the rainforest and its associated ecology after mining—an approach adopted by the newer and equally large Alcoa Juruti bauxite mine that operates in a similar Amazon rainforest environment.
A two-month sabbatical in November 2011 took Dr. Peter Whitbread-Abrutat, a mining and environment consultant specializing in mine closure and post-mining regeneration for Wardell Armstrong International, on a personal odyssey to explore world-class landscape restoration. He came face-to-face with some of the biggest environmental challenges in international mining—and found some equally surprising answers.
Supported by a traveling fellowship from the Winston Churchill Memorial Trust, his journey took him from mountain-top removal coal mines of Appalachia in the U.S. to the southern tip of South America, and from the Florida Everglades, Costa Rica and the Galapagos Islands to Atlantic rainforests and the farmlands and logged forests in the Chilean and Argentine Patagonia.
But it was in Brazil that he was able to assess first-hand some of the biggest impacts of international mining operations, as well as some of the most pioneering restoration measures to be found anywhere in the world.
A typical image of mining in this country is of artisanal miners (garimpeiros) causing environmental and human damage as they scrape gold and gemstones from the earth. But while such situations do exist, the real national wealth from Brazilian mining is produced by some of the biggest mines in the world.
He visited two of the largest aluminium mines in the Amazon: MRN’s Trombetas and Alcoa’s Juruti. Both have massive bauxite deposits, and take great pride in their reputations for corporate responsibility.
The Trombetas mine is located on the Trombetas tributary of the Amazon River. It’s the largest bauxite mine in the world. Mining began in the 1970s when there was little there but rainforest and small, scattered communities. Today, there’s an enormous surface mine and a mining town of a few thousand people, surrounded by the Saracá-Taquera National Forest protected area. A legal requirement to restore the forest has been in effect since 1984, with 9 million trees planted up to 2011 over 4,500 hectares to re-create high-biodiversity rainforest.
Alcoa’s Juruti mine, south of the Amazon, works another similar bauxite deposit containing an estimated 700 million metric tons (mt) of ore. The development is much newer, with mining only beginning in the last couple of years. The potential life of the mine could extend until the end of the century.
Both operations surface-mine bauxite deposits buried just a few meters below the roots of the rainforest. First, the forest is cleared and the commercial timber stockpiled. Then the topsoil (about 50 cm thick) and overburden (8-12 m thick) are separately removed and stockpiled for later use in reclamation. Once mining is completed, the topsoil is replaced and planted with rainforest tree seedlings.
But in fact, the process of rainforest restoration actually begins even before mineral extraction starts. Wildlife monitoring is initiated two years before and continues during forest clearance. Teams of trained local contractors scour the forest before clearance to remove and translocate slow-moving animals, such as sloths and tortoises, to previously restored forest areas. They also save important plant specimens like orchids, tree seedlings and the nests of stingless bees—vital for the pollination of many forest plants and trees.
The ultimate goal of the restoration team is to regrow the jungle so that it’s as close to the original as possible. Working in collaboration with Brazilian scientific institutions, Trombetas has been researching how best to do this for more than 30 years, using a systematic nursery and field research strategy. Since 1997, about 50 masters’ theses and 25 Ph.D. theses have investigated the developing ecology of these forests. Juruti, on the other hand, is adapting and building on a generation of Trombetas forest restoration knowledge.
Of the 180 tree species found in the local forest at Trombetas, about 100 are chosen for replanting. Selection is based on their speed of growth for soil protection, their ability to attract animals through fruit and flower production to import seeds from outside the area, and their use to people in terms of fruit and nut production, medicinal properties and timber. Around Juruti, the jungle contains about 460 tree species, of which 30 species are planted in the restoration schemes.
The Trombetas restoration work has provided the template for Juruti’s approach, and there’s a great deal of cross-over. Both mines, working with Brazilian forest scientists, are refining their rehabilitation practices. The latest initiative involves loose-dumping translocated topsoil from trucks and leaving it uncompacted. Rainfall washes these piles down to cover the surrounding subsoil, into which trees are then planted. Since no spreading is involved, this method improves tree establishment with fewer heavy vehicle movements, lower fuel costs and reduced emissions. The different soil depths also provide more ecological niches for colonization by other species.
A favorite tree species, for economic reasons, is the Brazil nut tree. Because of its complicated ecology, the tree doesn’t do well in plantations and will only grow in areas of standing rainforest. At Trombetas, 12 local village families help to collect seeds and raise seedlings to augment the half-million produced every year by MRN’s own nursery. Around 70 local people are employed to plant the trees during the wet season.
Although the restoration team constantly strives to improve their success rate of some 70%, the oldest planted areas at Trombetas are now becoming indistinguishable to the casual observer from the rest of the forest. In the very first areas planted in the early 1980s, the translocated stingless bee hives are thriving, epiphytes have been reintroduced from more recently cleared areas and a Brazil nut tree is already 40-m tall.
Even at Juruti, trees planted less than three years ago in a small pilot area already stand at twice a man’s height. The shade-inducing canopy is closing, light-loving weeds are shaded out and forest plants are gaining a toe-hold. New trees are coming in, spread from the feces of animals attracted to the newly planted forest areas. Slowly, the rainforest is recreating its own self-supporting web of life.
The tree species mix is subtly adapted during restoration to enhance long-term socio-economic opportunities for local people, while also rebuilding the forest’s ecological integrity. To see such world class work in action should go some way to offset the general public’s perception of large-scale destruction and devastation. Concerned and talented people are making genuinely inspiring efforts to regrow the forests and provide new environmental, social and economic opportunities in a rapidly changing world.
This article was provided by Wardell Armstrong (www.wardell-armstrong.com), a leading independent engineering consultancy specializing in mineral resource development and management. A personal account of this journey first appeared in the CSM Association Journal, 2011/12.