Marandoo Mine Phase 2 Dewatering

Marandoo Mine Phase 2 Dewatering

Rio Tinto’s (Marandoo Mine Phase 2 Dewatering Project) iron ore mine is located within Karijini National Park in the Pilbara Region of Western Australia. Expansion of the mine capacity requires mining below the water table. The project comprised the installation of approx 35km of MSCL pipelines ranging from DN500 to DN1000, 27 Dewatering bores, A 2.5ML collector tank, 2 pump stations and a contingency discharge to allow the water table to be lowered for the mining activities. The extracted water is used to supply the Hamersley Agricultural Project which was developed in conjunction with the dewatering
project.

The water will also be used to supply the town of Tom Price and for re-injection into an existing borefield.
WaterCon was engaged by Ertech to undertake the mechanical works for the project including:

• Workshop Fabrication of MSCL risers and above ground carbon steel pipework for the bore off take connections and pipeline appurtenances (air valves and scours).
• Workshop Fabrication of carbon steel pipe spools for the Transfer Pump Station, Booster Pump Stations and the Contingency Discharge.
• Supply of valves, instrumentation and pipeline components.
• Site installation of the pipeline appurtenances.
• Site installation of the pipework, valves and other mechanical works for the Transfer Pump Station and Booster Pump Station.
• Site installation of the pipework, valves and other mechanical works for the Contingency Discharge.
• Hydrostatic testing of the pipework.
• Pipeline Disinfection (Chlorination) of the Tom Price pipeline section.
• Commissioning activities associated with the works.

Site surveys were made and accurate 3D CAD models were created for the pump stations and pipework. This ensured site welding was kept to an absolute minimum and that any potential installation issues were identified prior to commencement of site works. The benefits of this methodology were reduced costs for the site installation works. The pipework fabrication and site installation was undertaken in-house by WaterCon. Pipework sizes ranged from DN100 to DN1000. All fabrication and welding was carried out in accordance with AS4041 Class 2P.