Experimental and Physical Analysis Applied to Tailing Dams

 

André Luís Brasil Cavalcante

Ph.D., Associate Professor, University of Brasília, Brasília - DF, Brazil, Department of Civil and Environmental Engineering, Zip Code 70910-900, e-mail: abrasil@unb.br

Luís Fernando Martins Ribeiro

Ph.D., Associate Professor, University of Brasília, Brasília - DF, Brazil, Department of Civil and Environmental Engineering, Zip Code 70910-900, e-mail: lmartins@unb.br

André Pacheco de Assis

Ph.D., Professor, University of Brasília, Brasília - DF, Brazil, Department of Civil and Environmental Engineering, Zip Code 70910-900 e-mail: aassis@unb.br

 

 ABSTRACT

deficiencies mainly due to the lack of control of hydraulic parameters. In general, the material is placed randomly and then these structures can present stability problems. The hydraulic parameters, such as flow rate and concentration of the slurry, present an important function upon the formation of hydraulic fills. Grain size distributions, segregation, densities and slope inclinations are the main characteristics of tailings dams, which are quite affected by the hydraulic parameters of the slurry. Concerning these investigations, an experimental apparatus (HDS test) was used to simulate the hydraulic deposition process in laboratory, where all variables that affect the phenomenon could be carefully controlled. HDS tests with different values of flow rate and concentration were carried out using the iron waste from the Morro Agudo Mine, Minas Gerais, Brazil (CVRD). The results presented in this paper are mainly related to the segregation patterns, mean grain sizes, specific gravities and densities obtained along the small-scale deposited beach in the HDS tests. The main objective of this investigation is to analyze the influence of the hydraulic deposition parameters upon the formation process of hydraulic fills, focusing on segregation and its importance to density and porosity values. Besides, a mathematical model has been developed to describe and to simulate the mechanism of formation of granular tailings dams based on momentum and continuity equations of the fluid and the sediments (quartz and iron). The model takes into account the main external variables (slurry concentration and flow rate) and internal variables related to the slurry mixture, such as mean particle size, grain density and relative percentage of iron and quartz. The analytical and numerical results of the model have been compared to deposition profiles obtained by the HDS test.

Keywords: Tailing dams, Hydraulic fill, Bed load transport; Laboratory; Physical simulation.

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