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Gold Mine Stockpile Cover

Challenge

In a world’s first application, Advantic engineers delivered a remedial structural system that enabled the safe and cost effective operation of a gold mine in Kalgoorlie, Western Australia by combining multi-material structural analysis, high tolerance manufacturing of structural polymer materials, focused “design for constructibility” expertise, and construction installation support.

Kalgoorlie Consolidated Gold Mines Pty Ltd(KCGM), a joint venture between Barrick Gold Corporation and Newmont Mining Corporation, had determined that a 258 foot (78.5 meter) suspended conical roof structure (stockpile cover) required structural remediation works to critical steel members in order meet business objectives of safe and sustainable production until the end of the life of the gold mine, currently projected for 2029. Site conditions included aggressive chemical attack coupled with damaging impacts by heavy earthmoving equipment.

The result was substantially reduced load carrying capacity of 80 foot (24 meter) long primary structural steel members undergoing compression and bending. Prior to Advantic’s involvement, KCGM engineers undertook substantial engineering investigation and analysis of the structure to understand critical loads, member forces and the subsequent risks to the business, via the assistance of traditional external engineering consultants. A number of conventional material solutions incorporating steel, concrete, and grout had been proposed with costs ranging from $8 million to $13 million AUD, each requiring an extensive shutdown period to complete the remedial construction effort, which would dramatically impact the operation of the plant and its ability to meet its yearly production targets. The large capital expense, coupled with the impact to production and operations amid volatile mineral prices, required the client to re-think the path forward.

KCGM looked to Advantic for an alternative solution.

  • Conventional Material Solution: $8 to $13 million AUD
  • Advantic Structural Jacket Installation: $3 million AUD
  • Cost Savings: $5 million AUD 63% less than the conventional

Solution

Recognizing that little guidance exists in the successful design and integration of advanced composite material solutions in infrastructure applications, Advantic provided a staged engineering approach as an integral activity within the project delivery program.

Engineering Design

After reviewing all existing documentation and studies on the structure, Advantic formulated conceptual solution approaches including analytical design methodologies, preliminary first principle analyses, and basic material selection and characterization. Preliminary design, however, does not end at the drafting table. A site visit enabled the Advantic team to meet with KCGM project management team as well as potential installation contractors. A concise agenda enabled the rapid extraction of information concerning critical construction opportunities and limitations as well as to build relationships with key personnel. Finite element analyses were performed on each critical structural member to investigate the optimized design geometries necessary to achieve minimum material performance requirements. Each member was modeled independently, including an accounting of all field-surveyed damage and cross section reduction due to corrosion. Leveraging strong relationships with global adhesives manufacturers, Advantic performed a further experimental program to identify and characterize performance for the design geometries and load paths. The final design solution involved a system-level approach incorporating multiple material interactions: stainless steel, thin bond line structural adhesive, Advantic polymer composites, and field-installed thick bond line structural adhesive. The solution took the form of hundreds of Advantic ‘jackets’ installed to provide continuous reinforcement of the existing structural members. Due to the criticality of the work and nature of the design solution, being a world first, KCGM requested third party engineering peer review of the design effort and outcomes, which was undertaken by two independent design firms.

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