Water table management in Hydraulic fill masses
Matthew Helinski, Tony Grice, Cameron Tucker,
High hydraulic conductivity in hydraulic fill masses combined with the non-plastic nature of most hydraulic fills makes susceptibility to piping failure a high possibility in many hydraulic backfills. In order to achieve a piping type failure within a hydraulic fill mass a static head of water must exist above the fill material. As a result many hydraulic fill operations adopt a filling and resting criteria to ensure that the phreatic surface remains below the fill surface. Due to many complicated characteristics simulation of stope drainage can be extremely difficult. Therefore, a conservative approach is often adopted. This conservative approach can lead to significant delays in the filling cycle which can have a major impact on the productivity of many hydraulic fill operations and can often results in a movement to adopt a more capital intensive paste fill system. This paper presents a technique for monitoring the elevation of the phreatic surface in a hydraulic fill mass and illustrates how this technique may be used to manage hydraulic fill run-rest times in an efficient manner. The implementation of this strategy has lead to a significant increase in filling rates at a number of Australian filling operations without compromising safety.
Mots Clés:
Insitu monitoring, Hydraulic Fill, Water management
