La Oroya is a city of about 33,000 people on the River Mantaro in central Peru. It is situated on the Altiplano some 176 km east-north-east of the national capital, Lima, and is capital of the Yauli Province. La Oroya is the location of a smelting operation that earned the town a place on the Blacksmith Institute's 2007 report, "The World's Worst Polluted Places".
First to be built was the copper smelter in 1922, followed by the lead smelter in 1928 and the zinc refinery in 1952. Annual capacities were 70,000 es lead and 45,000 tonnes zinc, although the need to keep below emission limits and temperature inversions that trap gases over the city, smelter and surrounding area have tended to keep production below these levels.
A number of local mines produce 'dirty concentrates' that contain metallic impurities that cannot be separated by the flotation process. Over the years, the La Oroya metallurgists have devised methods to separate and recover these metals as byproducts, and the three main smelters have become heavily integrated for this purpose. La Oroya is one of few smelting operations in the world with this capability. As a result, La Oroya produces gold and silver (mainly from refinery residues), antimony, arsenic trioxide, bismuth, cadmium, indium, selenium, tellurium, sulfuric acid and oleum This technology has helped the operation to reduce the emission of some noxious and toxic metals; however, the integrated nature of the plant has hindered the modification of individual parts of the plant. Source:
Wikipedia, La Oroya
In 1997, 99.97% of the La Oroya smelter was acquired by Doe Run Peru, a subsidiary (now an affiliate) of the Renco Group, for approximately US$247 million. The acquisition consisted of a capital contribution to Centromin's Metaloroya of US$126.5 million and a purchase price payment of US$120.5 million. Doe Run Peru also bought the Cobriza copper mine for US$7.5 million to maintain concentrate supplies to the copper smelter.
With the acquisition of La Oroya, Doe Run inherited a complicated and partially semi-obsolescent smelter complex. The operation had suffered from disrepair, previous owners had invested little in modernization or clean operations. As a result of years of pollution, the hills immediately around the smelter became completely denuded, the river became more toxic, and the health of area inhabitants suffered. Residents have been found to have alarmingly high concentrations of lead in their blood and in the drinking water, and many have bronchial troubles. A 1999 study (conducted two years after Doe Run's acquisition) showed high levels of air pollution, with 85 times more arsenic, 41 times more cadmium, and 13 times more lead than amounts generally considered safe.
Founded in 1999, Blacksmith Institute is an international non-profit organization dedicated to solving pollution problems in low and middle income countries, where human health is at risk. Since its inception in 1999, Blacksmith has completed more than 50 cleanup projects in 21 countries.