Ok Tedi Crusher Replacement Project

Scope of Work

Ok Tedi Mining Limited (OTML) operates a large scale copper and gold mining and processing facility in the Western Province of Papua New Guinea. Ore won from the open pit mine at an annual rate of 24 million tonnes feeds a processing facility consisting of a gyratory primary crusher, two parallel grinding modules, flotation and gravity separation and sulphur removal.

The operation commenced in 1985 and current life of mine plans see production continuing until at least 2024, and potentially beyond 2030 with an increase in resource and reserve inventory.  It is envisaged that a significant portion of the increased reserve material would be sourced from a cut back of the east wall of the pit and this cut back will realise a significant increase in ore milled, project life and project revenue. The existing crushing plant, screening plant and some of the conveying circuit is located at the crest of the current east wall of the pit and would need to be removed and replaced to allow a cut back to take place. This requirement to relocate or replace these facilities has developed into the Crusher Replacement Project (CRP).

The scale of this project is very significant, especially when considering the remote and mountainous location of the site, the degree of effort required to access the site with heavy loads and that the project is being self-executed by the OTML operations team. The gyratory crusher being installed is one of the largest machines of this type currently being manufactured in the world. Over 13,000m3 of concrete and over 2,500 tonnes of fabricated steel will be required to construct the new facility. The site itself required substantial pioneering earthworks to be undertaken by OTML to enable the plant to be constructed within the Ok Ningi valley. Overcoming the challenges posed by the site and executing a construction project of this magnitude are indeed a credit to the OTML team.

GR Engineering was awarded an EPCM contract in 2018 for the provision of engineering services to complete the detailed design for the CRP. The key objective of this project scope of work was to provide OTML with the necessary engineering services, procurement support and detailed design deliverables to enable the self-managed owner’s team to execute the construction and commissioning of the CRP. The scope of this contract required GR Engineering to undertake the following tasks:

  • Establish a design basis and a process design criteria for the processing facilities to be constructed;
  • Conduct design reviews, HAZID and risk assessments in conjunction with the OTML project team;
  • Select suitable process equipment and design the concrete and steel structures required to support the selected equipment;
  • Create technical specifications to enable the procurement of the process equipment, construction materials, fabricated items and site construction services;
  • Provision of the engineering design and management services required to undertake the creation of the detailed design deliverables;
  • Provide OTML with engineering assistance for the design of drainage diversions, sediment control structures and pipeline modification works;
  • Provide site based resources to assist the OTML team with the implementation of the engineering designs and supervision of construction activities.

Design works and the procurement of the process equipment and fabricated materials is complete. Site earthworks and civil works are well underway and erection of structural steel has commenced.

The new crushing, screening and crushed ore stockpile facilities will be completed and commissioned in early 2020. Once the new facilities have been fully commissioned and operating reliably at nameplate capacity, the old crushing, screening and conveying systems will be demolished to enable the mine cut back to proceed.

Providing Global Mineral Processing Solutions


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  • Client Ok Tedi Mining Limited
  • Award Date March 2018
  • Completion Date Early 2020
  • Location Western Province PNG
  • Project Manager Rod Schier 
  • Project Type Brownfields EPCM schedule of rates contract, detailed design and procurement support