1045 3. CASE HISTORY Nº2 - CLOSURE OF WASTE PILE, SIMÕES FILHO, BAHIA, BRASIL. Recently, the increase in the number of stackable structures, together with greater complexity and driven by the requirements established by standards ABNT NBR 13028:2024 and ABNT NBR 13029:2024, has motivated the mining sector to seek alternative solutions for the closure of piles, such as tailings and waste rock. These standards require projects to have greater environmental control and structural stability, reinforcing the need for sustainable solutions. Traditionally, closure systems for these structures are composed of natural layers, such as a waterproof layer of compacted clay; a drainage layer of granular materials (sand or gravel); and a surface layer of topsoil (fertile soil), with the aim of establishing revegetation. In addition to operational challenges, waste rock and tailings piles must meet a series of legal requirements that drive the use of more modern solutions. NR-22 requires geotechnical stability, efficient drainage, and continuous monitoring, while CONAMA Resolutions 369/2006 and 430/2011 address the recovery of degraded areas and effluent control, respectively, with a focus on acid drainage containment and water contamination prevention. In this scenario, geosynthetics have proven to be a viable, technically, and economically advantageous alternative, replacing or complementing natural materials in the functions of waterproofing, drainage, filtration, separation, and erosion control. 3.1 Problem • Stricter Brazilian regulatory requirements for the stability and environmental control of landfills (ABNT NBR 13028:2024 and ABNT NBR 13029:2024). • Technical and economic limitations of traditional solutions based solely on natural soil. • The need to reduce environmental impacts, the consumption of natural materials, and associated emissions. 3.2 Solution • The solution adopted for capping the waste pile was a multi-layer geosynthetic cover system, designed to waterproof, drain, stabilize, and protect the waste body, replacing traditional covers based exclusively on natural soil. 3.3 Description of the solution using geosynthetics To reduce the impacts described above, the use of geosynthetics placed on top of the tailings was proposed, with the configuration shown in Figure 12. Some relevant data on the closure: the closure cover was 0.30 m, slope height 10 m, slope ratio 3H:1V. Figure 12 - Typical section using geosynthetics.
RkJQdWJsaXNoZXIy MTM0Mzk2