Of total tailings deposited by Samarco in Fundão pond in last three years, Vale accounts for just 5%: understand how the process works
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Of total tailings deposited by Samarco in Fundão pond in last three years, Vale accounts for just 5%: understand how the process works

6/3/2016 6:00 PM

Vale wishes to clarify that of the total amount of tailings (mining waste materials) deposited in the last three years in the Fundão tailings pond, which belongs to Samarco, Vale accounts for just 5%. Contrary to media reports, Vale has not tampered with any information about the output of Alegria Mine, whose tailings were partially deposited in Samarco’s pond.

In 2014 and 2015, Vale sent an annual average of 700,000 m³ of fine tailings to Samarco’s pond. This represented approximately 5% of the total volume deposited there. Considering the three-year period from 2013 to 2015, the percentage was also around 5%. Before this period, the pond was less than 50% full.

If we compare the volume of tailings against the height of the dam, this clearly demonstrates that Vale’s share of total tailings was very low. The dam was 105 m high, while Vale’s waste materials stood no more than 3.06 m in height, i.e. 2.9% of the dam’s height. See the graphic below:

Vale has a licence for all its structures at Alegria Complex, including those related to the transfer of tailings to Samarco. Environmental Licence 133 was issued by the Minas Gerais State Environmental Policy Council (Copam) on August 4, 1995, and since then it has been renewed every five years. At the moment, the licence in effect is Operating Licence 0231.

Understand how iron ore is processed

Mining activity is similar throughout the world: it involves a long production chain and it generates value for all those involved. The production process requires structures to permit the separation of material with economic value, called ore, from materials without any market demand, called tailings.

In the case of Alegria Mine, the extracted material is sent to processing plants, where its iron ore content is concentrated. In this process, part of the material becomes an end product and is transferred to loading stockyards, while the material without any economic value is disposed of in tailings ponds.

Tailings ponds and their dams are designed and built in line with the most sophisticated and thorough engineering techniques, always in accordance with globally approved standards and seeking maximum efficiency and safety to receive these materials.

Tailings from Alegria’s processing plants are split into two kinds: sandy and fine. The large sandy particles, arising from flotation cells, go to the Campo Grande tailings dam, while the fine particles, also known as slimes, which come from thickeners, have been sent to Samarco since 1991. In line with an established commercial relationship, Samarco is responsible for the handling and final disposal of this material, and the monitoring and operation of its structures.

Vale uses best maintenance practices on its dams, which are systematically inspected and audited by specialist external consultancies. It strictly complies with all applicable legislation.

Vale reiterates its commitment to Brazil’s socioeconomic development, based on sustainability in the execution of its activities and relationships of transparency and respect with all its stakeholders.