Webinar: From Vision to Execution - Mine Planning from Long to Short-Term

In this webinar, K-MINE's Head of Mine Planning Department walks through the complete mine planning workflow - from long-term pit optimization to short-term production scheduling - using a gold-copper deposit as a practical example.

The session covers the full planning cycle that mine planners follow when developing a business plan for an open pit operation, demonstrating how each stage feeds into the next within a single integrated software environment.

Mine planning operates as a recurring cycle carried out at regular intervals. The process typically begins with deposit optimization at the life-of-mine level, producing optimal contours, pushbacks, and preliminary timelines with financial projections. Once the finalized contour and pushbacks are established, the focus shifts to pit design - integrating infrastructure, roads, and adjusting slope angles. With the design locked in, scheduling takes over to meet plant requirements and customer demands by aligning quality and quantity indicators across all planning periods.

Each stage feeds directly into the next, and plan adherence is monitored by comparing achieved milestones against targets and identifying the reasons behind any deviations.

The webinar begins with setting up the optimal pit boundaries model using the pit optimizer for a block model containing gold and copper. Key steps include defining economic parameters for each final product: gold price per gram with a recovery factor of 50%, and copper price per tonne with 90% recovery. Processing costs are set separately - enrichment cost at $7.77 per tonne of processed ore for gold, with lower costs for copper due to elimination of repeated crushing and grinding expenses.

The optimization algorithm identifies profitable block sets at various price adjustment coefficients. Coefficients triggering significant pit expansion indicate blocks suitable for determining pushbacks. The process is semi-automatic: the algorithm identifies profitable blocks, and the planner distributes them over time by segmenting them into separate pushbacks.

Wireframes are constructed based on the price adjustment coefficients, and each pushback encompasses blocks located above the defined wireframe while excluding blocks already included in previous pushbacks. A new feature allows recording each block's association with a specific pushback or mining period directly as a field in the block model, which can then be used for visualization.

A recently added capability enables simultaneous sensitivity analysis across a wide range of indicators, both for each final product individually and for general project economics. Users can define custom iteration steps and select which indicators to evaluate, helping quickly identify which parameters have the most significant impact on profit or net present value.

The generated report includes separate tabs for each defined final product along with a general indicators tab, allowing mine planners to assess how changes in commodity prices, recovery rates, or processing costs affect the overall project economics.

The dynamic design feature within the design model enables rapid creation of complex open pit configurations. Starting from isolines extracted from the optimization results, the planner selects reference lines that capture the pit shape as it expands from the base upward - specifically looking for distinctive horizon configurations rather than horizons that simply mirror the previous one with minor extensions.

The tool generates complete pit designs including bench configurations, ramp systems with switchbacks and flat spots, and edge definitions. The entire process takes approximately 30 minutes, compared to a full day or more for manual design. Multiple comparable scenarios can be created and evaluated to select the best fit.

The resulting design is integrated with the current topographic surface by identifying intersection lines, segmenting wireframes, and merging truncated surfaces into a single comprehensive outcome. All project lines can be trimmed at wireframe intersections for precision.

A new tool within the optimal pit boundaries model allows evaluation of design effectiveness - how closely the constructed pit matches the theoretical optimum. It enables comparison of multiple shells generated from various design scenarios, benchmarked against the economics of the optimization project. Results can be exported to Excel for detailed comparison across scenarios.

A step-by-step demonstration shows manual dump design in mountainous terrain. The process involves outlining the dump contour at its lower level, constructing tiers from the bottom up to a designated height, introducing offsets to create berms between tiers, and extending lines to intersect with the actual terrain. Ramps are added to complete the configuration. Because elevation decreases from the pit towards the dump, only one ramp remains accessible in the final result - the rest are filled in during the formation process. The completed dump is integrated with the topographic surface as a wireframe.

The production schedule model is designed to span all planning horizons within a single tool. The key distinction between planning levels lies in the input data: pushback operations drive long-term and medium-term planning, while their outcomes dictate short-term planning parameters.

The scheduling workflow follows 11 steps:

1. Import the block model constrained by the final development contour
2. Classify rock types present within the block model
3. Establish planning intervals to define the development scope
4. Segment the mine into planning areas starting with pushbacks
5. Define how each area will be mined and establish spatial relationships
6. Run the automated Solution Finder to optimize the excavation sequence
7. Re-evaluate and reshape planning areas based on the generated results
8. Adjust planning periods and excavation schedules
9. Introduce loading and unloading areas
10. Incorporate the rock mass transportation system
11. Run final calculations and examine results

The Solution Finder works based on predefined settings for each mining area, helping meet desired performance objectives for every planning interval. In the demonstrated example, the first two intervals target a rock mass plan considering upcoming excavation and deposit preparation tasks. Activity is limited in all areas except the first to simplify the algorithm's work. In the final period, only the mineral indicator is targeted, with overburden distribution following the residual principle.

The calculation results show that rock mass removal remains fairly consistent over the years and ore quantity is maintained at steady levels - suggesting the plan is viable for ongoing development.

Based on the long-term results, the schedule is reshaped while maintaining the block processing sequence. Mining areas are reconfigured to align with the planning intervals from the previous stage, with a clear development sequence established. For more precise detail within specific areas, blocks can be defined using polygons.

The detailed plan combines multiple time frames: four weekly intervals, three monthly intervals, four quarterly intervals, and five annual intervals. Two excavators are assigned with firm sequencing rules - proceeding to the next area only upon completing the previous one. This approach maintains the connection between ore and overburden, guaranteeing a continuous supply of material to the processing plant.

Dumping areas including reloading points, waste dumps, and the processing plant are incorporated into the schedule. The haulage network is configured by specifying origins, destinations, and grouping loads and dumping points. Cargo flow percentages can be allocated among multiple storage sites, and quality requirements can be set at delivery points to facilitate blending and averaging of mineral qualities.

The scheduling model provides multiple output formats. Results can be organized by planning periods with all data presented in the context of planning intervals. Wireframes can be generated for each mining period and automatically colored with distinct shades using the gradient field, allowing visual tracking of pit progression.

Users can monitor face progression on a daily basis with multiple visualization modes including expansion and reduction views. Data on excavated rock mass volumes remains visible from plan commencement through each individual day.

The most detailed report covers excavation of rock mass by individual blocks, with customizable data grouping based on user preferences. When a line is selected, the corresponding haulage route is visually displayed. Additional columns, formulas, and supplementary parameters can be added to the table, and all data can be exported to Excel.

• Pushback boundaries and mining sequences from the long-term plan should be strictly maintained when transitioning to shorter planning horizons
• The mining intensity between allocations should not change unless absolutely necessary
• Rock mass removal targets from the previous planning stage should be preserved at the same level
• The automated Solution Finder and manual planning methods work best in combination - use automation for the overall picture, then refine manually for detailed schedules
• If the schedule is unsatisfactory, first verify alignment with the global plan idea, then identify discrepancies and their causes
• Additional pushbacks can be added if conditions are not met, but this requires additional overburden volumes and associated costs that should be assessed comprehensively