AN INVESTIGATION OF THE STRENGTH AND DEFORMATION PROPERTIES OF PASTE BACKFILL MIXTURES

5th International Scientific Conference - SGEM2005, www.sgem.org, SGEM2005 Conference Proceedings/ ISBN: 954-918181-2, June 13-17, 2005, 177- 182pp

ABSTRACT

Paste backfill is composed of a mixture of mine tailings, process and/or fresh water for
the desired solid-water consistency and hydraulic binder to ensure a target mechanical
resistance. This paper presents some studies undertaken on the strength development and
deformation behaviour of paste backfill mixtures made from a Turkish zinc mine tailings. A
series of laboratory experiments was conducted to determine the strength and deformation
properties of paste mixtures with binder content ranging from 4 to 7 wt% and slump values of
6 to 7" at short term curing time (28-day). The physical, chemical, mineralogical and
rheological properties of tailing samples were first determined. Unconfined compression tests (UCS) were then performed on the paste backfill mixtures after 28-day curing time and the
stress-strain curves were recorded to analyse the sample deformation characteristics. It was
found that a paste cylinder with 7 wt% cement and 6.0" slump had a highest compressive
strength of 868 kPa after 28 days and the corresponding tangent and secant modulus of
elasticity are 83.1 and 58.3 MPa, respectively. This study revealed that UCS values and
deformation modulus of paste backfills are mainly controlled by the cement and binder
content used in mixture.