Dewatering of Multi-aquifer Unconsolidated Rock Opencast Mines: Alternative Solutions with Horizontal Wells

摘要

Horizontal directional drilling (HDD) can be a cost-effective way to dewater excavations and surface mines. Laboratory and field experiments provided insight into the important processes involved and allow us to reproduce them through modelling. A new algorithm based on the flow equation by Manning-Strickler was developed and introduced into the groundwater model, PCGEOFIM~R, which allows one to calculate open channel flow within HDD wells. The experimental and numerical results clearly showed that HDD wells have certain advantages over vertical wells, such as more cost effective dewatering in thin aquifers. Additionally, free flowing HDD wells dewatering technology allow mining to proceed without requiring the removal of the wells.