Ok Tedi Crusher Replacement Project: The Geotechnical Challenges Of Constructing Infrastructure On Top Of Soft Tailings In Remote PNG

H Panchalingam and D Piccolo

The Ok Tedi mine in Papua New Guinea needed to relocate their crusher infrastructure prior to an open pit cutback, and several project requirements and constraints including steep terrain and difficult time frames drove it to be built over the top of mine processing waste (tailings) up to 30 m in thickness. Consequently, geotechnical aspects of the project were a significant part of the design process and governed many of the construction decisions. This paper focuses on the consolidation and shear strength parameters of the tailings, and how the model evolved from an early concept, into one informed by targeted site investigations. Ultimately, loading trials on site with careful monitoring of settlement and pore pressures allowed the geotechnical model to be verified and refined based on actual field performance. It also presented a good opportunity to reflect on the influence and benefit each site investigation had on the geotechnical model and the resulting design decisions. The final part of this paper reflects on the overall design process, construction outcomes and lessons learnt.