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Jan 27, 2025

Determining the Number of Pushbacks

Determining the optimal number of pushbacks is key to balancing workload, costs, and profitability in mining operations. While fewer pushbacks simplify scheduling, they may lead to significant overburden, whereas more pushbacks offer better NPV but increase complexity. Learn how to find the right balance based on deposit size, equipment, and operational goals.

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Video transcription

Determining the right number of pushbacks is a critical aspect of mine planning, impacting operational efficiency, cost management, and overall profitability.

Key Considerations:

  • Fewer Pushbacks: While simplifying scheduling and reducing complexity, fewer pushbacks result in handling a larger overburden, leading to higher initial costs and delayed ore access.
  • More Pushbacks: Additional pushbacks provide better workload distribution, improve net present value (NPV), and ensure smoother ore access, but they also introduce higher costs and increased design complexity.

Our analysis shows that increasing the number of pushbacks from three to seven gradually improves NPV while reducing workload spikes. However, beyond a certain point, the incremental gains become minimal, and added complexity may outweigh the benefits.

Factors Affecting Pushback Size:

  1. Deposit Size: Larger deposits allow for bigger pushbacks, while smaller ones may require more frequent intervals.
  2. Equipment Capacity: The size of mining and transport equipment determines how pushbacks should be planned to optimize operational efficiency.
  3. Stripping Ratio: Maintaining a balance between ore exposure and waste removal is key to ensuring continuous plant operations.
  4. Scheduling Efficiency: Proper sequencing and timing of pushbacks can prevent unnecessary delays and maximize mineral recovery.

Best Practices for Pushback Design:

  • Each pushback should extend from the pit surface to its maximum depth, targeting the mineral deposit efficiently.
  • The pushback width should generally be a multiple of the working area of your equipment, with a recommended range of three to four equipment widths.
  • Pushbacks should follow a sequential approach, ensuring continuity and efficient resource utilization.

By applying these strategic guidelines, mining operations can optimize their pushback strategies, balancing operational feasibility with economic benefits.