Gregory Mine, an open-cut coking coal operation in the Bowen Basin, has been producing coal since 1979 and is currently owned by Sojitz Corporation. With an annual production capacity of 3 million tonnes, the mine exports coal via the Blackwater railway system to the port of Gladstone. Since Sojitz's acquisition of the mine in 2019, they've relied on Cat® GET (Ground Engaging Tools) for their ancillary fleet, specifically utilising EWL Cutting Edges on their LTTTs (Large Track-Type Tractors).

Historically, Sojitz managed their D11 dozers with a 500-hour PM (preventive maintenance) interval but faced issues with GET maintenance. Due to safety concerns, the GET was not changed in the field, necessitating two additional trips to the workshop within a 1,000-hour operating period. This practice significantly increased operating costs due to non-productive undercarriage costs, additional labour hours, and reduced physical availability of the machinery. 

Eager to reduce these operational costs and align with their PM strategy, Sojitz partnered with Hastings Deering to explore alternative GET systems. A trial was conducted with three D11s operating under similar conditions, each equipped with different GET systems:

• DZ38: EWL with ARM (Applied by Hastings Deering)
• DZ39: EEWL Middle Edges & HA End Bits (Note: HA Middle Edges were not available for the XU blades)
• DZ40: Offset Edge

The GET systems were inspected regularly, with wear trends recorded via a custom-designed inspection sheet and Excel spreadsheet. Hastings Deering created a 'Go No-Go' gauge to evaluate wear. The aim was to identify a GET system that could meet the 500-hour PM interval and offer the best cost-per-hour performance.

At the end of the trial, the Offset Edges showed the longest wear life and best cost-per-hour (CPH). However, there were concerns about alignment with the 500-hour PM strategy due to the offset wear material. Ultimately, Sojitz decided to adopt the EEWL Middle Edges with HA End Bits for their LTTT fleet. This choice was based on the following estimated savings and benefits:

• Material Savings: EEWL Middle Edges with HA End Bits were $0.79 per hour cheaper than the previous EWL fitment, translating to an annual saving of approximately $27,650 in materials across the fleet.
• Increased Production: By avoiding additional trips to the workshop, the machines gained an estimated 200 extra operating hours per year.
• Savings from Undercarriage Wear and Labor: The reduction in worn undercarriage and man hours was estimated to save $200 per hour, equating to $40,000 per year across the fleet. 

  

The switch to EEWL Middle Edges with HA End Bits at Gregory Mine is projected to save Sojitz around $65,000 annually in material and labour costs, alongside enhanced production efficiency. This successful trial underscores the importance of continuous improvement and strategic partnerships, with Hastings Deering playing a pivotal role in optimising operational expenses and productivity in mining operations.