Banca de DEFESA: Gabriel Gomes Silva

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Gabriel Gomes Silva
DATE: 28/03/2024
TIME: 10:00
LOCAL: Sala Teams (On-line)
TITLE:

ANALYSIS OF MECHANICAL AND HYDRAULIC BEHAVIOR IN CO-DISPOSAL OF MINING WASTE

KEY WORDS:

Co-disposal; Tailings; Waste Rock; Mechanical Behavior; Hydraulic Behavior.

PAGES: 81
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Geotécnica
SPECIALTY: Mecânicas dos Solos
SUMMARY:

The complexity of the behavior of mining tailings dams, constructed using the hydraulic deposition technique, and the recurring ruptures of these structures underscore the importance of ensuring enhanced safety through advanced disposal techniques. Although the co-disposal method has been explored for various mineral substances, such as iron ore in Brazil, there is a significant gap in the literature regarding its application to slimes, tailings, and waste rock originating from phosphate mining and other minerals. This study focused on the analysis of samples from three distinct mining sources: a phosphate mine in Brazil, a coal mine, and another phosphate mine, both located in Australia. The objectives included identifying the optimal proportion for mixtures of waste rock and tailings, waste rock and mud/slimes, and among different types of mud, in order to assess the mechanical and hydraulic behavior compared to individual materials. Comprehensive physical, chemical, microstructural, and mineralogical characterization tests were performed on the samples from the Brazilian mining, while the other samples underwent simplified analyses. Mechanical behavior was evaluated through direct shear and triaxial tests, while hydraulic behavior was assessed through permeability, suction, and tests in a large-scale consolidometer. The results indicated that the co-disposal of mining waste can result in materials with mechanical behavior dominated by waste rock or coarser materials, depending on the mixture proportion, suggesting that co-disposal can be an effective strategy for mining waste management. Additionally, hydraulic analyses revealed high drainage capacity of the materials, as well as dissipation of excess pore pressures over time. Furthermore, to replicate the stress-strain behavior of co-disposal, the Norsand constitutive model was calibrated using the results of triaxial tests as a reference. This study provided insights to optimize the practices of mining waste co-disposal, addressing crucial aspects of mechanical and hydraulic behavior in mixtures of different materials, as well as numerical analyses for constitutive model calibration.

COMMITTEE MEMBERS:
Externo à Instituição - MAURICIO EHRLICH - UFRJ
Interno - 404827 - ANDRE PACHECO DE ASSIS
Externo à Instituição - JOSÉ OTÁVIO SERRÃO ELEUTÉRIO - UFMS
Interno - 2161425 - JUAN FELIX RODRIGUEZ REBOLLEDO
Presidente - 3132829 - RAFAEL CERQUEIRA SILVA