Minimum Void Ratio Model Established from Tailings and Determination of Optimal Void Ratio

Shibo Li,Hao Li,Jianquan Ma,Hao Liang,Bin Li,José Luis Pastor

doi:10.1155/2021/8619121

Abstract

Minimum void ratio of tailings and its value change with fine content and are key design parameters for tailing consolidation and seepage stability. Based on the distribution of tailing grains with the sedimentary beach, we establish a minimum void ratio model for tailing grain in binary size, which requires only two parameters ( ε and ω ). Calibrations of the model using 168 groups of tests (22 kinds of grain size ratios with 7-9 kinds of fine contents) show two parameters that are fitting for power function, and the exponent values increase with the dominant grain size expanded. Besides, the exponent values are related to the equivalent grain size ratio, dominant grain size, and shape characteristics. The minimum void ratios with fine content are predicted under the derived model. Good agreement was obtained between the predictions and measurements, and the average discrepancies are less than 10%. And optimal void ratio and optimal fine content can be predicted, and the values are in good agreement with the experimental ones. Furthermore, based on the predicted optimal void ratio, the exponential relationship between the optimal void ratio and the equivalent grain size ratio may have no influence on the derived dominant grain size and shape characteristics. For tailings, further work is needed to verify if the derived exponential relationship between the optimal void ratio and the equivalent grain size ratio is valid.

Highlights

Over the last few decades, with the increase in the demand for minerals and metals, a large amount of mine tailings has been generated with the exploitation of mineral resources
As observed from the measured results of the minimum void ratio versus fine content, the minimum void ratio values conform to the triangle rule, the results are outside the inverted triangle range under the fine content exceeding by 60% for the patterns of silt-clay-sand tailings (Figures 5(a)–5(d))
A minimum void ratio model for tailing grain in binary size was developed for predicting the minimum void ratio, optimal void ratio, and optimal fine content, requiring only two parameters, ε and ω

Summary

Introduction

Over the last few decades, with the increase in the demand for minerals and metals, a large amount of mine tailings has been generated with the exploitation of mineral resources. The height and storage capacity of tailing dams have increased continuously during the past decades to meet the growing mine exploitation demand, which inevitably leads to the increase in the risk of tailing dam failure [1,2,3,4,5,6,7]. From the investigation of such tailings as copper, lead-zinc, molybdenum, tungsten, and phosphogypsum, it was found that the grain size of tailings generally does not exceed 2 mm. Most of the tailing investigations found that the tailing grains presented uneven size and distribution, which were an important factor affecting the safety of tailing consolidation and permeability [12,13,14,15]

Methods

Results

Conclusion