Ok Tedi Mining Ltd (OTML) operates the Ok Tedi Copper-Gold Mine located in the Star Mountains of the Western Province of Papua New Guinea (PNG). The mine is a porphyry style copper-gold deposit located at an elevation of 1300 – 2000 m above sea level.
Klohn Crippen Berger Ltd was engaged by OTML to establish a post-closure groundwater model for the Ok Tedi Mine open pit. This model was required as part of the Mine Life Extension (MLE) feasibility study to extend the mine life to 2025 as an alternative to closure in 2013. The purpose of this assignment was to predict the long term effects of the new pit drainage tunnel development on the formation of a closure pit lake and the potential for a closure pit lake to decant into Harvey Creek.
Aspects of this work included:
- Calibration of FEFLOW model with OTML pit model.
- Development of pit closure scenarios with consideration for different closure strategies.
- Description and analysis of OTML input data.
- Description and description of modelled simulations.
- Summary and interpretation of modelling results, including discussion of model sensitivity.
- Quantification/uncertainty analysis of error in pit lake predictions.
- Technical discussions relating to the results of modelled simulations and the implications results have on proposed closure strategies.