A Narrow Wall System to Capture Temperature-Stress-Strain Behavior in Paste Backfill

• Main Authors: Ting`, Wee Kiet, Alsidqi, Hasan, Fauzan, Sahdi, Siti Noor Linda, Taib, Norsuzailina, Mohamed Sutan, Badhrulhisham, Abdul Aziz, Andy, Fourie
• Format: Article
• Language: English
• Published: ASTM International 2017
• Subjects: TA Engineering (General). Civil engineering (General); TN Mining engineering. Metallurgy
• Online Access: http://ir.unimas.my/id/eprint/23311/1/Siti%20Noor.pdf; http://ir.unimas.my/id/eprint/23311/; https://www.astm.org/DIGITAL_LIBRARY/JOURNALS/GEOTECH/
• Institution: Universiti Malaysia Sarawak

Placing mine tailings back underground, into mined-out stopes, is becoming increasingly used internationally, providing as it does improve ore recovery, reduced dilution of valuable ore and environmental benefits due to reduced size of surface tailings storage facilities. In recent years a number of stopes backfilled with cemented paste backfill have been instrumented with load cells and piezometers, to improve our understanding of in-situ behavior. Many of these studies have reported results that show increases in measured total stresses when there is no increase in applied load, i.e. even when the backfilling process is long completed. One explanation is that these stress increases result from expansive volume changes of the backfill as it hydrates and generates heat. This paper proposes and describes a novel laboratory apparatus called narrow wall system to investigate this hypothesis, focusing on modeling narrow stopes as these are relatively common in backfill applications. Results from the experiments agree qualitatively with the reported field observations, showing clear increases in measured pressure during periods of temperature increase. The paper concludes that the proposed narrow wall system works effectively and has been able to capture the temperature-stress-strain behavior of paste backfill. Thus, the temperature effect hypothesis has now been supported by evidences. Using the system, further studies related to geometrical or scale effects are suggested. The results are important for academics and engineer to improve backfill design in mining operations.