The Mechanical and Microstructural Properties of Composite Structures Made of a Cement-Tailing Backfill and Rock Core

Yu-Ye Tan,Kai Zhang,Xin Yu,Wei-Dong Song,Jie Wang,Cheng-Long Hai

doi:10.3390/min10020159

Yu-Ye Tan, Kai Zhang + Show 4 more

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https://doi.org/10.3390/min10020159

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Journal: Minerals	Publication Date: Feb 12, 2020
Citations: 15	License type: CC BY 4.0

Affiliation: University of Science and Technology Beijing

Abstract

In underground metal mines that use sublevel or stage open-stope and backfilling mining methods (SSOBMMs), there is a special structure around which both sides of the rock pillar are wrapped by backfill. As a permanent part of an underground mine, how much can backfill improve the rock pillar’s compressive strength? What is the difference in the mechanical properties between the special structure and the signal rock? To explore these questions, a composite structure made of a cement-tailing backfill (CTB) and rock core (RC) was designed. Uniaxial and triaxial compressive strength tests and scanning electron microscope (SEM) were used to research the mechanical properties, failure process, failure characteristics, and microstructure characteristics of the cement-tailing backfill and rock core (CTB-RC) specimens. It was found that the full stress–strain curve of the CTB-RC specimen under triaxial compressive strength (TCS) test had two times the stress increases reaching a lower peak deviator stress two times after the RC was destroyed. The CTB can reduce the destruction and slow down the deformation speed of the inner rock cor (IRC). It can also prevent rigid slip of the IRC after it is damaged and maintain the stability and integrity of the overall structure. The findings of this study can provide some basic knowledge on the mechanical properties of the CTB-RB and provide theoretical guidance for the optimization direction of the width of the rock pillar and the room in mines using SSOBMMs.

Highlights

With the depletion of near-surface metal mineral resources, underground mining has become the main way to develop metal deposits
2020, 10, 159 underground stope using stage open-stope and backfilling mining methods (SSOBMMs), how much can the cement-tailing backfill (CTB) improve the rock pillar’s compressive strength, and what is the difference in the mechanical properties between the structure and signal rock? Research is still needed in the area
Materials and Methods underground stope using SSOBMM, how much can the CTB improve the rock pillar’s compressive strength, and what is the difference in the mechanical properties between the structure and signal rock?

Summary

Introduction

With the depletion of near-surface metal mineral resources, underground mining has become the main way to develop metal deposits. More mining workers have begun to pay attention to whether mining methods can control underground stope pressure and maintain permanent stability of the stope [1,2]. The filling mining method has significant advantages in controlling ground pressure activities, maintaining structural stability of the underground stope, and reducing solid waste discharges [3]. As the mining depth continues to increase and governments vigorously promote green mining methods, the filling mining method has become increasingly more widely used for underground metal deposits in China [4,5]. Mirzababaei et al [12,13,14] studied the behavior of soft clay reinforced with short fibers, and found

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