Tailings dams


About Vale tailings deposit

What amount of waste from its mines was deposited by Vale in Samarco dams?

In 2014, Vale sent to Samarco the amount of 1,005,581 tons of waste from the Alegria mine, in Minas Gerais. This amount represents 4.4722% of the total amount deposited in the dam Fundão between January 2014 and December 2014. Click here to access the Samarco Financial bill (Portuguese only).

Is the waste from the dams toxic?

No. The waste at the dam sites is inert, it has no toxic components. It is mainly composed of silica (sand) from the iron ore processing and contains no chemicals that pose a risk to health. The results of the analyzes requested by Samarco to SGSGeosol Laboratórios, specialized in environmental and geochemical analyzes of soil, attests that the waste from the Fundão dam offers no harm to people or the environment. Samples were collected on November 8th near Bento Rodrigues, Monsenhor Horta, Pedras, Barretos and Barra Longa, in the state of Minas Gerais, and were analyzed according to the Brazilian standard NBR 10004:2004. These sites have been identified for collection for being the closest to the accident, and therefore the samples represent the best material deposited in the dam. After the analyzes, the waste at these sites has been classified as non-hazardous. This means that the analyzed material presents no harm to people and the environment, considering that it provides no contaminants to water, even in rain exposure conditions.

About tailings dams

Do these structures have an emergency plan that covers the hypothesis of their bursting? If so, what measures do they provide for?

Vale has Tailings Dam Emergency Action Plans (PAEBMs) for all the structures that are required to have them according to legislation. These plans present mitigation and communication procedures that must be followed in emergency situations in order to preserve life, health, property and the environment. These plans contain general information about the dam in question, define the areas affected if they should hypothetically burst, and set out preventive and corrective procedures for emergency situations, as well as notification and communication procedures, including warning systems and general responsibilities. Samarco has informed that the communities impacted by the accident have been visited by their teams with orientation regarding the emergency procedure. The people were informed about the location and how to reach the sirens installed and the meeting points at each location.

Do the Germano and Santarém dams face a risk of bursting?

: Samarco has declared, at the press conference held on Tuesday, November 17, that its dam and dike structures are stable. The company has a control room, with employees monitoring the dams 24 hours a day. Daily inspections are being conducted by the company´s technical team. At the Germano unit in Mariana, Minas Gerais, the Selinha Dike’s current safety factor is 1.22. This means it is 22% above the minimum equilibrium, which is 1.0. In the case of Santarém, the current figure is 1.37, meaning it is 37% above the minimum equilibrium point. Emergency works have being carried out for containment and reinforcement to increase the safety factor and reduce risks Into the structures resulting from the accident. Standard NBR 13028 establishes that in normal operating conditions, the safety factor must be at least 1.5, i.e. 50% above the equilibrium limit. Find out more on Samarco’s website.

Has Vale taken any steps involving its dams following the occurrence in Mariana? What measures have been taken?

Vale carried out a detailed inspection of the structural conditions of all its tailings dams. No alterations were detected. The following components were checked: access roads, tailings ponds, crests, berms, slopes, surface drainage, internal drainage systems, abutments and overflow systems. Eighteen geotechnical professionals from Vale’s ferrous minerals area, as well as a number of office teams, have been working on an emergency basis, contributing to the speed of the inspections’ results.

How are the dams monitored?

Our dams undergo visual inspections and are monitored using instruments that provide responses regarding their structural behaviour. The monitoring data is analyzed by geotechnical engineers, who frequently evaluate whether instrument readings are compatible with the structures’ normal operating conditions.

What dam monitoring standards are followed, and what do they involve?

When developing designs for dams, Vale complies with the criteria of standard NBR 13028, as well as the design guidelines of renowned international organizations, such as the International Commission on Large Dams (ICOLD). During the dam operating period, Vale complies with state and federal laws. In Brazil, Law 12,334 of 2010 establishes the National Dam Safety Policy, and National Mineral Production Department (DNPM) ordinances 416/2012 and 526/2013 govern Dam Safety Plans (PSBs) and Tailings Dam Emergency Action Plans (PAEBMs), respectively. In Minas Gerais, Vale complies with regulatory rulings 62/2002 and 87/2005, which govern dam classification criteria, as well as safety management requirements.