The Seepage and Stability Performance Assessment of a New Drainage System to Increase the Height of a Tailings Dam

Chong Liu,Lei Gan,Zhenzhong Shen,Liqun Xu,Kailai Zhang,Tian Jin

doi:10.3390/app8101840

Abstract

Effective methods for extending the storage capacity of tailings for a mining company include expanding and increasing the height of the tailings dam. However, this change could lead to an uplift in the phreatic line and a decrease in the slope stability. In this paper, a new drainage system combining a horizontal drainage pipe with an upward bending slotted pipe was proposed and applied to the design of a seepage-proof system for the Xigou tailings dam with an increased height. To accurately simulate the performance of the seepage control system, a three-dimensional finite element model was established on the basis of a geological investigation of the site conditions. In this work, a substructure technique was used to model the drainage pipe with a small radius and dense spacing to reduce the difficulty in mesh generation, and a back-analysis method called MPSO-BP (modified particle swarm optimization algorithm and a back propagation neural network) was used to correct the measured permeability coefficients. The results show that the new drainage system can effectively dissipate the seepage pressure, decrease the phreatic surface, and improve the safety factors of the slope stability. The proposed drainage system can also meet the seepage stability requirements of the higher tailings dam. Additionally, this system can be widely deployed in similar projects.

Highlights

A tailings dam is a large-scale, man-made structure that is constructed worldwide to keep waste tailings away from ongoing mining activities where tailing are mixtures of crushed rocks [1].Waste tailings pose a potential hazard to communities and ecosystems near mining areas [2]
The performance assessment of the proposed seepage control system after the of the dam was increased was described under extreme operating conditions using the previously height of the dam was increased was described under extreme operating conditions using the proposed method
The process of increasing theInheight of the the dam was divided into five stages to simulate the sequential raising of the dam

Summary

Introduction

A tailings dam is a large-scale, man-made structure that is constructed worldwide to keep waste tailings away from ongoing mining activities where tailing are mixtures of crushed rocks [1]. Waste tailings pose a potential hazard to communities and ecosystems near mining areas [2]. The upstream construction method is the main method for raising tailings dams [3]. In China, there are 14,000 tailings dams (in operation, inactive, and abandoned), and more than 90% of these dams are constructed using the upstream method [4]. Dikes are sequentially constructed on the previously deposited tailings, which may be present in a saturated and loose state.

Methods

Results

Conclusion