Multidisciplinary studies on the ok tedi project
From 2006, SRK Australia and SRK North America have performed studies contributing to several components of the Ok Tedi copper-gold mining project. The mine is situated in a mountainous, seismically active region with difficult access and extremely high rainfall. Complex structures and poor rock mass conditions present a particularly challenging mining environment. Key issues addressed at the site included slope stability and pit wall depressurisation, pit drainage, and waste dump stability.
Initial studies involved investigation and design for an underlying tunnel to facilitate drainage as the pit was progressively deepened. Extensive further studies contributing to the scoping, pre-feasibility, and feasibility study components of the mine life extension project (MLE) included the following:
• Geotechnical and hydrogeological investigation, characterisation, and modelling of the mining area
• Mapping and reinterpretation of the mine structural model
• Underground mining options studies, with subsequent pre-feasibility-level design and risk assessment for cave mining beneath the west and east pit walls
• Feasibility-level geotechnical studies for stability assessment of the 1,000 m high West Wall cutback design and the East Wall cutback design
• Hydrogeological modelling to evaluate pit wall depressurisation and drainage measures for ensuring slope stability and dewatering
• Numerical stability analyses to facilitate design of a 600 m high valley waste dump
• Stress and deformation analyses for assessment of underground mine stoping design.
In 2012-13, SRK reviewed and re-interpreted the existing conceptual site hydrogeological model, then helped implement a combined geotechnical and hydrogeological field drilling and testing program in support of final pit design evaluations. Complex 2D and 3D seepage and stability modelling formed an important part of these evaluations, which involved an integrated effort from the SRK Australia and North America teams.
