- PO Box Z5328, Perth St Georges Terrace WA 6831
Sector: Resources
Client: Aspec Engineering
Location: Olympic Dam, South Australia
Services Provided: Estimating, Scheduling
Background
The Clark Stacker forms part of the Clark Materials Handling System at Olympic Dam and is a long travelling, slewing, luffing, balanced machine, that stacks approximately 8.5 Mega tonnes per annum.
The operation of the Clark Stacker sees material brought to the surface by the Clark Hoist, placed onto the overland conveyor and raised onto the Stacker by the Tripper. The Stacker is controlled remotely to place material onto stockpiles, which sit over the tunnel reclaimer system and feeds the mills. The mills are the beginning of the surface treatment plant at Olympic Dam.
WHAT WE DID
The Clark Stacker Life Extension project requires an approximate 5-week shutdown of the Stacker for a comprehensive refurbishment, aimed at ensuring safe and reliable operation of the Stacker until 2047.
MGA were assigned by Aspec Engineering to prepare a Class 4 Estimate and Schedule for the Clark Stacker Life Extension project, with the scope including all structural, mechanical, electrical, instrumentation, and control systems on board the stacker and tripper.
HOW IT TURNED OUT
MGA successfully provided a timely and accurate cost estimate constructed using first principles build-ups based on an activity-based approach. Activity-based estimating methodology is suited to estimating, on projects where quantities are not the key driver. Parent crew rates are established using combinations of child rates (primary resources) based on the various activities being carried out and the labour, plant and equipment required to perform those activities. The crew rates are applied to the individual activities, based on the estimated durations of each.
Importantly, when applying this principle to the estimating process, MGA considers Non-productive Time (NPT) and Productivity Efficiency Factors (PEF) within the overall duration for each activity. This differs from quantity driven estimating techniques, where the NPT and PEF are applied separate to the production rate. These estimating principles were carefully explained to our client.
As a result, the client has expressed satisfaction with our work and has requested that MGA propose a fee for the upcoming Class 3 estimate.