Cerro de Pasco is a Peruvian city with two striking characteristics. Not only is it the most elevated city on the planet, at 4360 metres above sea level, it also lies on the edge of one of the world’s largest open-cast mines.
The mine’s official name is “Mina de la Volcan, Compañía Minera”, but to the inhabitants of Cerro it is simply “El Tajo” (the Pit).
The area’s mining traditions stretch back centuries. It is said that in the 16th century, the gold paid to Spanish conquistadors in ransom for the release of Inca emperor Atahualpa came from local mines. However, Cerro de Pasco remained a trading hub until the 1950s, when the Cerro de Pasco Copper Corporation decided to convert a small mine in the city centre into an open-cast mine in order to extract copper, lead, nickel and silver.
Down the years the mine has expanded dramatically, engulfing entire districts of the city, and is now a huge crater measuring 1.8 km long, 1.6 km wide and 800 m deep.
Unfortunately, as is also true in other countries throughout the region, social development has not necessarily kept pace with industrial development. Exacerbated by the political instability that plagues a number of Latin American countries, as well as serious social inequalities, intense mining exploitation in Cerro de Pasco has caused widespread and heavy pollution that has contributed to a cancer incidence rate of 40%, compared with a global average of 9.5%.
It was not until the end of the Fujimori government in the late 1990s that things began to change, slowly but surely. From 2007, a series of government acts initiated the slow and painstaking process of environmental and social regeneration in the area.
The World Health Organisation has carried out a series of studies to limit the impact of pollution caused mainly by the use of heavy metals in mining processes, while the government and local municipalities have launched a series of measures to improve local infrastructure, supported by various international agencies.
These interventions include the reconstruction of some sections of Cerro’s road network (initially using beaten earth), together with the construction of an efficient drainage system.
This major undertaking on the roof of the world, nearly 4,500 meters above sea level, involves a number of concrete L4700 mixers, one of the company’s most successful products.
As is common throughout South America, road surfaces are made of concrete, which is cheaper, easier to maintain and more suited to heavy traffic than European roads. Before the road surface is laid, electricity and sewage ducts are built into the formwork.
Using this system it is possible to build long stretches of road in a short time. The L4700 is highly appreciated for its total self-sufficiency in preparing mixture and for its rotating drum, which is indispensable in the narrow mountain streets of Cerro.