Incorporating Indigenous Technologies into Enhanced Stormwater, Erosion and Sediment Control Systems

The Antamina Mine is located in the mountainous region of the Ancash Department of Peru at an elevation of approximately 4200m. The 120 km main access road crosses the headwaters of numerous high-value trout streams and is adjacent to pristine lakes, some of very high ecological and scenic value. In addition, the mine discharges mine water and tailings supernatant to the Antamina and Ayash watersheds. These streams provide the primary water supply for irrigation by local residents and provide excellent fishery habitat.

The rock walls and earthen diversions constructed by historic and current indigenous residents of Peru are world -renowned and local residents continue this tradition, passed down from the Inca Civilization, for both agricultural purposes and water distribution. The key elements of sustainable development – economic, environmental and social development have been incorporated into Antamina’s sustainable development program through integration of indigenous knowledge and capabilities into enhanced storm water, erosion reduction and sediment control systems.

Examples of incorporating indigenous technologies and knowledge into cost-effective and environmentally sound environmental controls are: (1) placement of rock walls on steep terrain to reduce slope length and erosion, (2) installation of rock walls (porous rock check dams) within elongated sediment ponds to increase detention time, (3) construction of rock-lined ditches to convey clean water (4) use of rock walls, with or without geotextile, to function as a seep berm, and (5) appropriate selection and usage of native Andean species for protection of canals and sediment ponds, and steep slopes.

Operation at the Antamina Copper-Zinc Mine in Central Peru

Production at the Antamina Copper-Zinc mine in central Peru started in June, 2001. The operation was designed for a nominal milling production rate of 70,000 tpd. Components of the tailings management facility include a 130 m high concrete faced rockfill dam, 1300 m of decant tunnel and 14 km of water diversion channels and pipelines. At start-up, the tailings pond was 90 m deep and contained 15 million m3 of water. The dam and foundation are instrumented with settlement cells, total stress cells and piezometers. This paper presents the performance of the dam during filling of the impoundment with water and then tailings. The tailings deposition plan is compared to the actual tailings configuration as determined by the periodic bathymetric surveys. During mill commissioning, the tailings pond water was not suitable for discharge. The changes implemented in the mill and tailings impoundment to achieve water quality criteria are presented. These changes achieved the water quality objectives as well as reduced the overall re-agent costs.

Licensing and Permitting of the Antamina Project

The development of the Antamina Project was a milestone in Peruvian mining history. It was not only the largest private investment in the history of the country, but also the largest Greenfield mining investment in history. The project faced many difficult challenges, such as its remote location, high altitude, lack of infrastructure, and difficult technical issues such as the transport of concentrate through a 302 km. Concentrate pipeline. In spite of these challenges the project was constructed a head of schedule and under the original $2.3 billion budget.

Antamina and Huascarán National Park

A Case Study in Mining, Conservation and Sustainable Development

The Antamina project is located near Huascarán National Park (HNP), in the Peruvian Andes. The Park is designated as a United Nations Education, Scientific, and Cultural Organization (UNESCO) World Biosphere Reserve and World Heritage site. A Working Group was formed by the Peruvian Park Authority (INRENA) and is composed of the World Conservation Union (IUCN), and non-government organizations (NGOs), with the goal of monitoring the Antamina project activities, to direct mitigation associated with the construction phase of the project, and support protection of the Park resources. All major mining companies in the area are participating in the working group whose goal has been expanded from simply monitoring the activities of Antamina on the parks central route, to working towards sustainable development within the area of influence of the park. This paper discusses interactions of Huascarán National Park and the Mountain Institute (TMI) with the Antamina project and the development of a formal consensus building entity, the Huascarán Working Group (HWG). This case study represents a model for win-win conflict resolution outcomes that can be applied to other natural resource projects in proximity to protected areas or communities.

The Antamina Project — The Challenge of Sustainable Development in Peru

The Antamina project is a $2.3 billion copper/zinc project, located in Peru, and is designed to produce up to 1.5 million tonnes per year of copper and zinc concentrates over a 23-year project life. Project financing included securing $1.32 billion of senior loans from 22 export credit agencies and commercial banks and required the project to comply with a variety of national and international standards. Antamina has been innovative in its approach to a number of environmental, and cultural issues, and as a result, has set new standards in Perú for environmental and community management, and sustainable development.

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