INTERNATIONAL SEMINAR on TAILINGDAM TECHNOLOGIES & MANAGEMENT – MINAS GERAIS

Ten Dutch companies visited Minas Gerais to participate in the INTERNATIONAL SEMINAR on TAILINGDAM TECHNOLOGIES & MANAGEMENT. The program started on January 23th with a visit to the Mina do Pico site of Vale. After an introduction on the mining site, two tailings dams were visited with an explanation on the monitoring system installed and how the dams are managed.

The seminar was opened Wednesday January 24th, in Belo Horizonte, by the Secretary of Environment & Sustainable Development of the State of Minas Gerais (SEMAD), Germano Vieira and the Ambassador of the Kingdom of the Netherlands in Brazil, Han Peters, among others.

Secretary Vieira recalled the visit to The Netherlands of October 2017 which inspired to organise this seminar. The Netherlands is highly susceptible to both sea-level rise (26% of the country is below sea level) and river flooding (29% is sensitive to river floods). This Dutch territory is protected by a total of 17.000 km of dikes. These dikes are increasingly under pressure due to climate change. Softening caused by high water or desiccation due to prolonged drought can cause dikes to collapse. As a result, effective dike monitoring is vitally important. Due to the huge extension of the dike network and the high riks involved, the Dutch have developed construction techniques as well as innovative inspection and monitoring techniques for the detection of failure mechanisms in dams and dikes.

The visit to The Netherlands, organized by the Netherlands Business Support Office (NBSO) in Brazil, followed in line of the prioritization on monitoring installed by the State Government of Minas Gerais after the episode of the collapse of the Fundão Dam, in Mariana, together with a taskforce. The taskforce resulted in initiatives that aim at the modernization of laws, as well as the adoption of more stringent criteria for the management of dams in the state. The secretary recalled that Minas has sophisticated environmental programs, such as the Dams Management Program developed by the State Foundation for the Environment (Feam), which accompanies the stability condition, among other factors, of the dams located in Minas Gerais.

The objective of the seminar was to discuss these new policies and to present new technologies to the mining companies to help to implement them. Minas Gerais has more than 315 tailing dams, 50% of the total in Brazil. Besides well organised and monitored dams, such as the Mina do Pico dam of Vale, many dams require attention and are manually monitored. A new law, currently in process, will oblige mining companies to automatise the monitoring of their dams and to make the data available online to SEMAD.

Renato Teixeira Brandão, head of the department of Waste Management of the State Environment Foundation (FEAM), presented details of the Program for Management of Dams developed in Minas Gerais since 2002. According to him, the registration and the information system allows the data consultation of each of the structures. “The companies that own dams have the obligation to periodically present to the Government of Minas Gerais the declarations of stability that must be made by independent auditors,” he said.

“The data, as well as the conclusions and recommendations, are registered in the database of Environmental Statements, in an environment that enables quick consultation,” explains Brandão. “In addition to inspections, we have risk management actions carried out in the state,” he adds. In 2017, 275 dams were inspected.

The superintendent of the National Agency of Mineral Production in Minas Gerais (DNPM), Pablo César de Souza, presented data on mineral production in the country. According to him, in 2017, the Department that regulates the mining sector administrated about 37 thousand mineral extraction permits, 17 thousand mining records and 40 thousand research permits. After the reformulation in 2017, dam management control practiced by the federal agency has brought new requirements for the mining companies, such as the creation of self-rescue zones and a clearer definition of corporate responsibility.

The keynote speech* was given by professor André Assis, of the University of Brasilia. He presented a history of the evolution of dam management and analysis of the risks of structures in the country. According to the researcher, in the 1950s  risks were incorporated into decision making. In the 1970s environmental impacts began to be observed, while in the 1990s the entire environment began to be observed, including factors such as people, environmental and historical patrimony.

Assis defended the monetization of risk, with the entrepreneur including in his budget the value of the consequences of possible events. “For the calculation of the possibility of failure, factors such as quantitative analysis, risk indicators and scenarios should be taken into account,” he said.

The second part of the seminar discussed the advances and challenges in the implementation of technologies for dam management.

• Marilene Lopes of Vale S.A.Vale presented the Integrated Geotechnical Risk Management System based on three pillars: Security, Risk and Emergencies Management.
• Leonardo Padula of Kinross presented their management information system used for construction projects, monitoring, legal issues and the operation of Kinross dams. He also presented the challenges he faces in the field of perfectioning their tailing dam management program.
• Silvana Cembranelli of Mosaic Fertilizers presented a Microseismics and geophysics application in the safety assessment of tailing dams.

During the second day of the seminar the Dutch companies presented their approach, experiences and techniques in dam technology & management. The Netherlands invests a lot of time, energy and money in developing new products and projects to improve the safety of living in a vulnerable delta. Many solutions that apply to the Dutch situation can also be implemented in the field of dike and dam safety improvement of mining operations.

Dutch companies not only presented their products and technologies but also an integrated approach where various companies team together to offer a complete and integrated solution. An example was presented by Deltares on the DAMSAFE project in India, a cooperation of Deltares, SkyGeo and Eijkelkamp using measurement tools of Van Essen and risk assessment consultancy by Witteveen+Bos. It consists of the integration of different technologies, that have been developed and proven elsewhere and provide high quality and reliable information to the end-user. They allow assessment of the dam condition resulting in optimization of Operation and Maintenance (O&M), while rapid and risk based assessment of dam safety provides information for emergency response and improved risk reduction. Another example is Dijkmonitoring Netherlands, a cooperation between Arcadis and Intech (among others), specializing in innovative inspection and monitoring techniques for the detection of failure mechanisms in flood defenses.

A third group of companies presented their techniques based on keeping tailings dry and dredging techniques. Hencon presented an innovative dewatering technique using the so called Mudcrawler. By keeping tailings dry, and even allowing reuse of the water extracted, the tailings will be layered dry and thus stable, thereby diminishing the risk and impact of possible dam failure.

Dredging techniques have developed over the past year enabling mining companies to re-proces tailings and extract minerals existent in tailings (sometimes tailings carry a higher percentage of mineral concentration than the mine itself) and thereby increasing the operational lifespan of tailingdams, hence diminishing the need to construct new tailingdams. Dutch Dredging, Royal IHC and Damen showed their available specialized dredges tools and services for the use in tailing and hidro power dams.

After the seminar, on January 26th, the Dutch companies were received at CEMIG, by Mr. Diego Balbi, responsible for the security and maintenance of the 64 dams and dikes currently operated by CEMIG for the generation of hydro power. He presented the current system in place (mostly visual inspection and manual reporting) and the plans to automate the monitoring of these dams and dikes. Again, the Dutch delegation presented their visions and products after which there was time to discuss the possibilities for cooperation with the engineers and managers of CEMIG.

The presentations given by the Dutch companies during the seminar can be accesed by clicking on the presentations below. The contact details are listed below.

Monitoring, Modeling and Data Processing (Deltares, Van Essen e Eijkelkamp)

Deltares

Van Essen

Eijkelkamp

Risk Assessment, Decision Making and Consultancy (Witteveen & Bos, Arcadis e Intech)

Witteveen+Bos

Arcadis

Intech

Tailing Disposal and storage, Dredging and Dewatering (Damen, De Boer, IHC e Hencon)

Damen

Dutch Dredging

Royal IHC

Hencon

The presentations held by the Dutch companies are available online. The companies can be contacted directly for further information and explanations.

*Sources: http://portaldamineracao.com.br/sindiextra-e-feam-promovem-seminario-para-debater-gestao-de-barragens/