42 / 2021-08-17 00:06:41

Backfill strength mobilization monitoring with time

backfill, UCS tests, backfill mobilization, cemented backfill

5^th International Symposium on Mine Safety Science and Engineering

Katowice, Poland – November 21-25, 2021



Backfill strength mobilization monitoring with time

Zarina Mukhamedyarova^1,*and Fidelis Suorineni<sup>2

1</sup>School of Mining and Geosciences, Nazarbayev University, Nur-Sultan, Kazakhstan

²School of Mining and Geosciences, Nazarbayev University, Nur-Sultan, Kazakhstan

*corresponding author: Tel +77719059999 email: zarina.mukhamedyarova@nu.edu.kz



ABSTRACT



Mining at depth always creates voids. To provide safe and economically feasible mining of adjacent stopes these voids can be filled with backfill. Backfill decreases dilution and instability by restricting rock movement to the mined-out area. Cemented paste backfill is more preferable to non-cemented backfill as it reduces the risk of wall failure and could flow through delivery pipes.  Cemented paste backfill is a mixture of tailings, cement, and water.



Backfill performance in minimizing local and regional mining instability depends on the optimum proportions of filling materials. Therefore, UCS tests were performed to evaluate the strength behavior of prepared backfill samples with different cement content and curing time. Samples with a diameter of 37 mm, lengths in the range of 79-84 mm, and cement content of 5%, 10%, 15%, and 20% were prepared in wooden molds.  Through 1-28 days of curing the UCSs were determined to see the effect of different cement contends on the backfill strength. UCS test results showed increasing backfill strength with increasing curing time and cement content. Moreover, UCS tests together with Acoustic Emission measurements were conducted on 10% cement core samples at 1 day, 7 days, and 14 days to see the correlation between peak AE counts and peak stress.















Acknowledgment

This project is financially supported by the Collaborative Research Project of the Provost Office of Nazarbayev University. The authors are grateful for their support.