Following the disaster, a group of 96 institutional investors (representing more than $10.3 trillion assets under management) have written to 683 extractive companies seeking greater disclosure on the management of tailings storage facilities.
The companies addressed, including major names in the mining industry such as BHP, Rio Tinto, Anglo American, Glencore and Vale itself, have been given 45 days to publicly disclose their dams’ size, construction methods and safety records.
The move is aimed at providing a tool for institutional investors to assess the risk from their holdings in mining companies
About 100 investors, led by the Church of England Pensions Board and Sweden’s public pension fund, expect the companies to publish the answers to 20 questions sent, covering issues such as the height and type of dams they have, their capacity, engineering records and safety checks.
Industry group the International Council on Mining and Minerals (ICMM) said in March it was working with the United Nations Environment Programme (UNEP) and the Principles for Responsible Investment (PRI) to develop new standards.
Currently there are no set of universal rules defining exactly what a tailings dam is, how to build one and how to care for it after it is decommissioned.
There are about 3,500 tailings dams around the world. Unlike the ones used to build reservoirs or hydroelectric projects, tailings dams are not usually made from reinforced concrete or stone. They are mostly constructed from the waste material left over from mining operations, which — depending on the type of mine — can be toxic.
Only three countries in the world ban upstream dams — Chile, Peru, and now Brazil. Chile, the world’s No.1 copper producer, also regulates the minimum distance between dams and urban centres. But the nation still has 740 tailings deposits, only 101 of which are active, with the rest abandoned or inactive, according to data from mining agency Sernageomin.