A Mine Water Management Plan

With an approximate area of 115 km², Cerrejón is the largest open pit coal mine in the world. It is located in the Ranchería river basin, in the intermediate zone of the Guajira Peninsula - Colombia. The Ranchería river has an extension of near 4070 km², more than 3000 water users, more than 1600 users of groundwater, and an average flow, as it passes through the mine, registered at the Cuestecita station, of approximately 12.5 m³/ s.In this context, the Mine Water Management Plan was developed to plan an manage the use of water in the mining complex and to make an efficient use of the water for the projected expansion of the coal production.

The mine currently works in 5 open pits, divided into 3 large areas called Centro, Expanded West Pit (EWP) and Nuevas Areas Mineras (NAM). The demands of water within the mining complex, according to their nature, are classified into three types: roads irrigation, industrial use and domestic use. Road irrigation is the main use, and consists in moistening the road corridors that give access to the mining exploitation pits and their permanent expansion zones, such as the minor access roads to the production support zone. To satisfy these demands, the surface runoff and precipitation waters of the Mine’s area, as well as the underground waters of the Ranchería River, are used.

For the development of the Water Management Plan, a management and planning model for the use of the water in the Mine was developed. In this model, the Ranchería River, as well as the rainfall stored in the different pits, were introduced as water sources. More than 40 regulation reservoirs, piping and pumping systems were considered, as well as the uses described. In addition, to have an adequate water management of the Mine, a model of the Ranchería river aquifer was developed, maintaining a principle of sustainability that would allow its long-term conservation.