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Evolution in revegetation of iron-ore mines in Minas Gerais State, Brazil

J.J. Griffith and T.J. Toy

James Jackson Griffith is Professor
in the Department of Forestry
Engineering, Federal University of
Viçosa, Viçosa, Minas Gerais, Brazil.

Terrence Joseph Toy is Professor in
the Department of Geography and
Geology, University of Denver,
Denver, Colorado, United States.

A history of corporate reclamation practices, from the 1970s to the present, for open-pit iron-ore mines in Minas Gerais, Brazil's most important mining state.

Iron-ore mining in Minas Gerais State, Brazil, has a 300-year history in a challenging environmental setting. Some of the world's most abundant and high-quality reserves occur in the Quadrilátero Ferrífero region of southeastern Brazil, a mountainous terrain that is picturesque for sightseers but difficult for large-scale mining. Summer rains are torrential (precipitation up to 1 200 mm per year), and the ecosystems of the region are highly diverse, including Atlantic rain forest, cerrado savannah and high-elevation grassland (campo rupestre). Several open-pit mines each produce over 15 million tonnes of ore per year, making Brazil one of the world's leading iron-ore producers. On average, Minas Gerais mines produce about 1 tonne of waste for each tonne of ore. This means that enormous quantities of spoils must be moved and disposed of in a suitable manner.

This article tells how reclamation practices on these degraded lands have developed over the past 25 years. It illustrates how strands from all disciplines of knowledge have intertwined to promote progress in corporate policies, technical developments, new regulations, institutional strength and maturation of environmental philosophy (Barth, 1989; Toy and Griffith, 2001).

Large open-pit iron-ore mine near the metropolitan region of Belo Horizonte, Minas Gerais



Mining reclamation practices have developed along with the general evolution of Brazil's corporate environmentalism. Hoffman (1997) proposed that a country's history of corporate environmentalism can be divided into distinct time periods or stages. Over the past 70 years iron-ore mining in Minas Gerais appears to have passed through four stages: environmental disregard, industrial environmentalism, regulatory environmentalism and strategic environmentalism. The gradual accumulation of environmental impacts during each stage eventually triggered a significant environmental event which, in turn, led to the next stage. Examples apply mostly to large firms because they have more capital to invest in environmental programmes and thereby become sector leaders.

Stage I - environmental disregard (1934 to 1977)

For many years, mining companies focused on ore production and generally denied the existence of environmental problems. Mining began to change when the Brazilian Mining Law of 1934 and the Constitutions of 1937 and 1940 reserved subsoil mineral rights as the property of the government and authorized mining concessions. Iron mining expansion after the Second World War began with the inauguration of steelworks at Volt Redondo in 1946. President Juscelino Kubitschek included in his Programme of Goals a plan to increase ingot-steel capacity in Minas Gerais by an additional 1 466 000 tonnes in the period 1962 to 1965. Many of the early steelworks were fired by charcoal, and industry expansion resulted in large-scale, uncontrolled deforestation (Dickenson, 1967).

At mine sites, the most obvious environmental impacts resulted from the practice of dumping spoils in "bota-foras" (dump outs) at any convenient location. These unconfined disposals of wastes and slimes eroded badly and often filled many kilometres of stream courses with sediment. Land around the mines seemed too abundant to cause concern. The general attitude of mine managers could be described as "let nature heal the wounds", and indeed some plant species such as Vernonia polyanthes, Ricinus communis and other pioneers eventually would appear. But it often took decades before new plant communities became established on rugged cuts, dumps, pit high walls and sediment deposits. Many of these abandoned areas never stabilized and continued to slump and erode, which made plant establishment impossible. On more stable lands, aggressive non-native plants such as Melinis minutiflora often invaded the denuded areas.

Uncontrolled disposal of iron-mine overburden and spoils in Itabira region, Minas Gerais, typical of the 1980s but no longer practised


Stage II - industrial environmentalism (1977 to 1988)

Mining reclamation in Brazil began only after public protest in 1977 at Belo Horizonte, the capital of Minas Gerais. The primary complaint was environmental degradation of the landmark Serra do Curral ridgeline above the city, caused by extraction of ore from a large open-pit mine. The city's major newspapers published many editorials and articles protesting against various mining impacts. Criticism focused on deforestation carried out to enlarge a sediment containment reservoir and the visual disfigurement of the original contour of the ridgeline. Many citizens felt that the impacts from the mine symbolized a general deterioration in the quality of life.

Concerned that government might intervene, mining companies nationwide paid attention to the Belo Horizonte case. Several firms, especially in Minas Gerais, began voluntary environmental-impact mitigation measures, including revegetation projects. Leading companies sought reclamation solutions through their own internal technological capabilities. Interference from government or the general public, while not entirely ignored, was considered intrusive. Engineers responsible for these initial programmes used plantings to protect vital earthworks such as sediment containment dams and to stabilize road cuts. Many lands unsuitable for mining but part of an overall concession were planted with commercial tree species (Eucalyptus spp. and Pinus spp.) to avoid invasion by poor squatters.

Several important advances in environmental engineering and revegetation occurred during this period. The first university extension bulletin concerning reclamation practices was published and included several examples of Brazilian iron mines (Griffith, 1980). In 1982, the first controlled spoils disposal site with a planned drainage system and topographic reconstruction was installed at a mine in the Mariana region. Legal decisions prompted companies to improve their environmental programmes. For example, in 1986 a lawsuit was brought against the state's largest mining company in the Itabira region, alleging, as in the 1977 Serra do Curral case, that iron mines caused damage to native vegetation and disfigured the natural terrain. As a result of pressure from the state court, the mining company undertook a large urban reforestation programme, setting out in two years 212 000 transplants of approximately 200 species. In 1987, the Federal Department of Mineral Production conducted a training course in several large cities, entitled "Pollution Control in Mining" (Brazil, National Department of Mineral Production, 1987).

Revegetation projects often used hydroseeding revegetation methods (e.g. with Brachiaria decumbens, Melinis minutiflora, Lolium multiflorum). Trees of Leguminosae-Mimosoidae and Melastomataceae were also planted, often supplied by company-operated nurseries. Grass (Paspalum notatum) sod was used to protect spoils containment dams and to enhance highly visible sites such as roadside cuts near company offices. Undesirable vistas of mining operations were frequently screened from roadside view by planting of dense rows of Eucalytus spp., Casuarina sp. and Pinus spp.

Several mining companies sponsored the first comprehensive evaluation of Brazilian mining reclamation practices (Barth, 1989). The reclamation at some mines was found to be excellent, comparable with reclamation anywhere in the world. However, more than 50 percent of Brazilian mines were not engaged in any form of reclamation at that time. The general conclusion, based on Barth's 1987 sample of mines, indicated lack of long-term planning for post-mining land use. Other practices identified as needing improvement included topsoil salvage, hillslope stabilization, soil erosion and compaction control, planting site preparation, soil analysis and fertilization, species selection, seeding techniques, post-revegetation site management and organization of reclamation research programmes (Toy and Griffith, 2001). The report noted that many of these problems were recognized and were being addressed.

Stage III - regulatory environmentalism (1988 to 1999)

The Federal Constitution of 1988 declared in Article 225 that "Those who explore mineral resources are obligated to reclaim the degraded environment, according to the technical solution demanded by law by the appropriate public agency". This specific requirement ushered in another evolutionary period, characterized by technical compliance by larger companies to federal, state and municipal environmental laws (Hoffman, 1997). Unfortunately the results of this compliance were limited, because the environmental laws and regulations enacted after 1988 to implement the constitutional mandate were very broad and regulatory responsibility was too dispersed among various agencies (Nascimento, 2001). In some cases laws overlapped. For example, Article 224 of Belo Horizonte's Organic Municipal Law, enacted in 1990, protected the Serra do Curral ridgeline from further disfigurement by declaring it a natural monument. This law supplemented but mostly just reiterated a similar federal action taken in 1960 to preserve the same landscape.

Nevertheless, regulatory progress was made in air and water pollution abatement, detonation control (especially mitigation of noise levels of rock blasting near urban areas) and topographic reconstruction of mined-out pits and overburden (geologic material overlying ore) spoil deposits. New federal legislation which supported such improvements includes a decree of 1989 requiring preparation of a Plan for Reclamation of Degraded Areas (PRAD); a decree of 1990 passing jurisdiction to the state environmental agency to issue and control important mining licences, including the PRAD; four resolutions of the National Council for the Environment (CONAMA) between 1990 and 1997 which further regulate mining licences and environmental guidelines; and the 1998 Law of Environmental Crimes, which sets forth administrative and penal sanctions for conduct or activities that inflict injury on the environment (Toy and Griffith, 2001). Based on experience at Minas Gerais iron mines, the Brazilian Association of Technical Norms developed a specific industry-wide standard for spoils disposal in mining (Associação Brasileira de Normas Técnicas, 1993).

In 1992, the first of four national symposia on reclamation of degraded lands, organized by university reclamation scientists, was held in Curitiba, Paraná State. The four symposia held to date have become the principal forum for Brazilian reclamation research. They have also motivated companies to take a more ecological approach in revegetation projects. Even so, most mine managers continued to focus on short-term control of erosion or aesthetic goals (Toy, Griffith and Ribeiro, 2001). Perhaps to placate visiting inspectors and others, they opted for a "green carpet" approach - using rapidly growing, aggressive exotic species for quick restoration of vegetative cover (Griffith, Dias and Jucksch, 1996).

Revegetation projects during this period increasingly relied on hydroseeding with greater diversity of species (e.g. Cajanus cajan, Dolichos lab-lab, Avena strigosa, Glycine wightii). Tree and shrub transplants were set out, with the use of fast-growing native species (e.g. Senna machrantera, Tibouchina granulosa, Vismia guianensis) and introduced species (e.g. Acacia mangium, Leucaena sp.). Special attention was given to the use of legumes (e.g. Acacia holosericea, Enterolobium contortisiliquum) to provide a nitrogen source. In some cases, topsoil saved from newly opened mines was applied to sites prepared for revegetation. Scientists and managers cooperated in experiments to develop new forms of propagule dispersion ranging from installing bird perches (which resulted in dispersal of Cecropiaceae, Melastomataceae and Rubiaceae) to applying forest litter (e.g. Croton urucurana, Vanillosmopsis erytropappa) and spreading residential garden and lawn trimmings (e.g. Bougainvillea spp., Calliandra brevipes, Calanthea spp.) directly on exposed substrates (Toy and Griffith, 2001).

In the previous stages, plantings were ignored after establishment, but now companies began investing in maintenance and protection against fire, insects, illegal grazing and plant disease. Sponsorship of environmental education programmes for industry workers and local schoolchildren became popular and served to improve corporate image.

Silva (1993) successfully revegetated very steep pit slopes at an iron-ore mine in Conselheiro Lafaiete by staking to hill-sides jute sacks filled with soil, fertilizer, organic material and seeds of Brachiaria ruziziensis, Cajanus cajan, Stizolobium aterrimum and others. A cottage industry of biodegradable mat manufacture developed from this initial experience, and today highway departments and railroads, in addition to mines, use these mats for revegetating steep slopes. Areas around industrial plants and public roadways near mines were enhanced by planting standard urban forestry species such as Bauhinia variegata, Caesalpinia peltophoroides and Callistemon citrinus. Mining companies were legally required to protect Natural Preservation Areas within their concessions, and several companies contracted species inventories for forest fragments found on their lands.

Revegetation of steep slopes at Viçosa, Minas Gerais, using jute sacks filled with soil, fertilizer, organic material and seeds


Stage IV - strategic environmentalism (1999 to the present)

In 1999, the first International Standards Organization (ISO) 14001 Environmental Quality Certificate for mining was awarded to a multinational iron-ore company in the region of Mariana. Some other mining companies began to initiate similar programmes, but whether this will become a trend is not yet clear. Such certification requires establishment of an Environmental Management System through which the corporation structures its performance in response to environmental risks and market opportunities in accordance with its institutional vision.

This stage is distinguished by the introduction of new players into the corporate organizational field - investors, insurers, competitors, local communities, etc. (Hoffman, 1997). This expansion obliges companies to incorporate environmental considerations into overall management strategies rather than relegating them to low priorities in their organizational hierarchies. Certification programmes require candidate companies to present proof of community involvement - but so far there is little evidence of this occurring. Another major problem is the continuing lack of long-term post-mining land use plans (Toy and Griffith, 2001; Nascimento, 2001; Barth, 1989; Toy, Griffith and Ribeiro, 2001).

At the technical level, engineering practices continue to evolve, including installation of roadside erosion control (sediment traps), topographic reconstruction for better integration of reclaimed and natural landforms and watercourses, and wildlife habitat creation (boulder piles for refuge). Most companies promote industrial-area scrap collection and recycling. Toxic materials (laboratory test materials, batteries, etc.) are now isolated in special areas and properly disposed of. Many companies have garbage-recycling programmes, and some have experimented with applying compost from cafeteria waste in revegetation projects.

For reclamation specialists, a key task at present is to convince administrators that revegetation projects can contribute in multiple ways to a company's Environmental Management System. Many innovations for better plant establishment have appeared, some developed with university collaboration. More sophisticated biodegradable mat systems with embedded seeds and a variety of weaves are now commercially available. New ingredients such as cigarette filter tow and cotton linters have been added to hydroseeding ingredients. Specialists are using more site-specific ecological approaches - precision revegetation tailored to site conditions - rather than applying a uniform planting recipe everywhere. Attempts are being made to integrate preserved forest fragments with newly revegetated areas, fostering synergistic relations among plant and wildlife communities. Reclaimed areas are monitored to ensure that, once planted, vegetation will be maintained in a healthy state, protected from fire, insects, disease and illegal grazing.

Highly eroded and unstable phyllite substrate on slope alongside iron-mine railroad in Mariana region, Minas Gerais


The same railroad sideslope regraded, planted and protected by biodegradable mat



This review of Brazil's evolution in corporate environmentalism for the specific case of iron-ore mining suggests the following conclusions.

The evolution of corporate environmentalism continues worldwide. Given the complex differences in physical and socio-economic conditions in individual countries, it is difficult to predict what the next stage in Brazil will be or how it will affect revegetation techniques at iron mines. Hoffman (1997) predicts that in the United States the next historic stage will depend on how corporations, together with other interested parties, define and assimilate the concept of sustainable development. In Brazil, perhaps the biggest influence on mining organizational culture at this writing is the recent and ongoing consolidation of large iron mine ownership by one company. The ramifications of this for environmental management, for certification programmes at mines, and specifically for revegetation practices should provide an interesting next chapter in Brazil's reclamation story. 

Landscape reconstruction in progress of mined-out lands in Mariana region, Minas Gerais


Mined-out lands reconstructed and recently revegetated by hydroseeding in Mariana region, Minas Gerais



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