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Designing Precision: Automatic Borehole Placement as the Core of Smarter Blasting

Blasting is one of the most decisive operations in surface mining. The way boreholes are placed on a bench face determines whether the blast delivers uniform fragmentation, safe breakage, and cost efficiency — or leaves behind oversized boulders, excessive vibration, and wasted explosives.

For years, engineers relied on manual layouts and rules of thumb. But irregular benches, corners, and variable face conditions often broke those rules. The result: compromises in safety and efficiency.

Automation and 3D modelling are now shifting this balance. 3GSM’s BlastPlanner within the BlastMetriX suite, introduces a geometric, data-driven approach to borehole placement. The key is aligning boreholes to minimum burden criteria, hole by hole, across any bench geometry.

 

Why Borehole Placement Matters

Borehole placement defines powder factor efficiency, fragmentation quality, and overall blast safety. A misaligned hole can create flyrock hazards or zones of under-blasting. Conversely, precise placement improves every downstream step of mining – from mucking to hauling to crushing.

Traditionally, burden is measured by 2D profiles: a cross-section between a borehole and the free face. But this approach struggles with complex geometries. Corners, irregular crests, and face deviations make it unclear which direction should define the “true” burden.

Figure 1. Traditional burden profiles are ambiguous in corners or irregular faces.

The Innovation: Minimum Burden Concept

The method arranges boreholes based on geometric principles aligned with the true minimum burden. A spherical search around the borehole is performed to determine the minimum distance to the surface, regardless of direction, and is graphically represented in the minimum burden diagram.

It accounts for the actual three-dimensional shape of the free face and accommodates various spatial orientations of the boreholes, including their position, inclination, and deviation. The extension of the several minimum burden diagrams involves calculating minimum burden surfaces indicating optimal locations where boreholes should be placed to maintain the design burden. Placing boreholes along these surfaces ensures consistent compliance with design rules across the entire face.

Figure 2. Profile vs. minimum burden of a borehole visualized on the 3D model
Figure 3. Plot representation of the profile vs. minimum burden of the borehole.
Figure 4. Minimum burden surfaces extend the concept of burden diagrams into 3D, producing borehole positions that align perfectly with design burden.

Automation in Action: Workflow in BlastPlanner

BlastMetriX turns these concepts into practice with a structured workflow:

  1. 3D model generation: Photogrammetry produces a high-resolution 3D model of the bench.
  2. Design input: Engineers specify design burden, spacing, and row count.
  3. Automatic placement: Algorithms compute minimum burden surfaces row by row and place boreholes accordingly.
  4. Pattern optimization: Rows adapt to curved, angled, or irregular faces, while color coded burden visualization confirm compliance.
  5. Per-borehole validation: Each borehole gets a profile, sectional area, and minimum burden diagram, visible in real time.
Figure 5. Automatically positioned boreholes meeting the best minimum burden criterion for a curved corner blast with showing minimum burden surface for six rows. Burden distribution over the entire bench face is colored according to different burden levels.

Transparency and Control

Automation doesn’t mean black-box design. Engineers can still adjust boreholes manually— moving or editing them with spreadsheet-style controls — while burden plots update instantly. BlastPlanner also generates detailed reports with per-hole profiles, burden diagrams, and sectional data, giving teams a fully auditable design record. This balance of automation and control ensures patterns are not only optimized but also transparent and accountable.

Benefits for Engineers

  1. Safety: Burden control reduces flyrock and misfires.
  2. Efficiency: Optimized placement improves fragmentation and reduces secondary breakage.
  3. Cost Control: Accurate positioning of boreholes ensures consistent powder factor.
  4. Transparency: Each hole’s burden, and placement rationale can be documented and audited.
  5. Adaptability: Works equally well in straight benches, corners, and irregular geometries.


The Cornerstone for Optimized Mining Operation

Automatic borehole placement is more than a design aid. It is the cornerstone of a larger optimization cycle. Connecting blast design with blast analysis, creates a closed feedback loop that allows for traceable and well-documented site optimization. This approach enables step-by-step, reproducible refinements to surface blasts by taking into account specific site characteristics. Over time, this control loop drives continuous improvement, reducing costs and environmental impact while enhancing safety.

Figure 6. The principle of the blast optimization process.

Conclusion: From Concept to Audited Science

Automatic borehole placement, grounded in minimum burden surfaces, is more than a feature — it’s the future foundation for smarter, safer, and more sustainable blasting. BlastMetriX technology have set a new standard: repeatable, measurable optimization that brings engineering rigor to daily mining operations. Automation makes it precise, auditable, and adaptable. For engineers, it means faster designs, greater confidence in safety margins, and demonstrably better results in the field.