HDS has undertaken three horizontal drilling campaigns at OZ Minerals’ Prominent Hill mine throughout the life of its open pit (Now successfully completed to a depth of 482m).
The most recent program involved removal of groundwater from a horizontally bedded clayey overburden sequence by intersecting permeable polygonal fault structures that are pervasive within the unit.
Specification of the programme involved the drilling and casing of 500m deep horizontal drains while maintaining the drill traces within a narrow 30m horizontal slice throughout the length of the hole.
By using a collaborative client-contractor approach that involved the use of downhole surveying, various drilling tools and adjustments to drilling techniques, the specifications were achieved.
The programme yielded more water than previous programmes involving the drilling of vertical holes with pumps installed.
The holes continue to yield significant volumes of water and provide groundwater pressure reductions behind what was previously a slope where stability was a focus.
Throughout the programme (and previous programmes), HDS completed thier work in a professional and safe manner. Demonstrating a willingness to comply with all site requirements, recording zero breaches, incidents, near misses or injuries during this time.