Ring Design Workflow

A detailed walkthrough of each step in the BlastCAD ring blast design process.

Table of contents

  1. Step 1 — Select DTM Surfaces
    1. Required Surfaces
    2. How to Import Surfaces
  2. Step 2 — Draw the Baseline
    1. Drawing the Baseline
    2. Baseline Geometry Requirements
  3. Step 3 — Place Rings
    1. Ring Placement Controls
    2. Placing a Ring
    3. Ring Section View
    4. Managing Rings
  4. Step 4 — Design Holes
    1. Using Drill Templates
    2. Pivot Configuration
    3. Rig Constraint Checking
    4. Manual Hole Placement
    5. Delay Assignment
  5. Visualizing the Completed Design

Step 1 — Select DTM Surfaces

Before any drilling geometry can be generated, BlastCAD needs to know the physical surfaces that define the blast domain.

Required Surfaces

Role Description
Collar DTM The surface where drill holes begin (typically the drive floor or ring drive level).
Target DTM The surface the holes must reach (the stope hanging wall or ore contact).
Drive DTM The drive outline used to define the baseline corridor.
Stope DTM The stope envelope — used for proximity checking and overbreak prevention.

How to Import Surfaces

  1. Open the Import Center (Ctrl + I).
  2. Select Surpac DTM and upload the .dtm + .str file pair.
  3. The surface appears in the Explorer Panel under its layer.

In Step 1 of the Ring Workflow panel, click the dropdown for each surface role and select the matching imported DTM from your layer list.

Tip: You can use the same DTM for multiple roles (e.g., the same hanging wall surface for both Target and Stope) if your geometry allows it.

Step 2 — Draw the Baseline

The baseline is a 3D polyline that defines the central drilling axis — the path the drill rig follows through the drive. Rings are placed perpendicular to (or at a configured dump angle from) this axis.

Drawing the Baseline

  1. In the Ring Workflow panel, click Draw Baseline.
  2. The Draw Baseline tool activates in the canvas.
  3. Click points along the drive floor (use OSNAP Endpoint to snap to the Drive DTM boundary).
  4. Press Enter or right-click to finish.

The baseline polyline is visualized in orange in the viewport. It drives all subsequent ring placement calculations.

Baseline Geometry Requirements

  • The baseline must be a connected 3D polyline (no gaps between segments).
  • It should follow the drive centreline — not the wall or floor edge.
  • The baseline’s direction vector at each point defines the normal plane in which the ring sits.

Step 3 — Place Rings

Rings are cutting planes positioned along the baseline. Each ring is a plane that intersects the stope volume. Holes are drilled within each ring plane.

Ring Placement Controls

In Step 3 of the workflow panel, configure:

Parameter Description
Burden Distance between consecutive ring planes along the baseline (m). Typical range: 1.0 – 3.5 m.
First Offset Distance from the start of the baseline to the first ring (m).
Dump Angle Tilt of the ring plane relative to perpendicular (°). A dump angle compensates for the direction of advance and drilling access. Positive = ring tilts toward the drive face.

Placing a Ring

Click Add Ring in the panel or click directly on the baseline in the viewport. BlastCAD:

  1. Computes the tangent direction of the baseline at the clicked point.
  2. Constructs a plane perpendicular to the baseline (modified by the dump angle).
  3. Registers the ring with its position, normal vector, burden value, and dump angle.
  4. Switches the camera to a 2D orthographic view looking straight into the ring plane.

Ring Section View

Once a ring is selected (active), the viewport automatically displays a cross-section view showing:

  • The ring plane outline (derived from the drive DTM)
  • The collar and toe DTM intersections in that plane
  • Any holes already placed on the ring
  • The ring’s normal vector orientation

Managing Rings

Action How
Select a ring Click the ring marker in 3D view, or click the ring name in the workflow panel
Rename a ring Double-click the ring name in the workflow panel
Reorder rings Rings are automatically ordered by baseline position
Delete a ring Right-click → Delete ring
Adjust burden Edit the burden value in the ring’s properties — updates the ring position along the baseline
Adjust dump angle Edit in the ring’s properties

Step 4 — Design Holes

With rings placed, you can now populate them with drill holes. Holes can be:

  1. Generated from a Drill Template (recommended for production patterns)
  2. Manually placed (click-to-create in the ring section view)

Using Drill Templates

Drill Templates define the geometric arrangement of holes relative to the ring’s pivot point. A template specifies:

  • Number of holes and their type (reamer or easer)
  • Offset from the ring pivot (dx, dy in the ring plane)
  • Hole diameter per hole

Applying a template:

  1. In the Ring Workflow Step 4 panel, click Apply Template.
  2. Select a template from your Drill Templates database.
  3. BlastCAD projects each template hole from the ring pivot point, applying rig constraints.

Pivot Configuration

The pivot is the reference point at which the drill rig is positioned for the ring. BlastCAD uses it to compute all hole trajectories.

Parameter Description
Pivot Height Height of the rig’s rotation pivot above the drive floor (m). Default: 1.8 m
Pivot Height Min/Max Constraint range for the pivot height
Drill Rod Length Length of each drill rod (m) — affects achievable hole depth
Carousel Dimensions Rod change mechanism dimensions — affects minimum pivot clearance
Carousel Feed Distance Distance from the drill steel to the drive wall for carousel operation

These parameters come from the Rig Database — see Drill Rigs.

Rig Constraint Checking

When holes are generated from a template, BlastCAD automatically validates each hole against the rig constraints:

Constraint Check
Min/Max hole length Rejects holes longer or shorter than the rig’s capability
Min/Max dip angle Flags holes that require impossible rig inclinations
Dump angle limits Validates the ring’s dump angle against the rig’s angular limits
Carousel clearance Checks that the rod change operation fits within the drive profile

Constraint violations are shown as red warnings in the Properties Panel and in the Command Terminal.

Manual Hole Placement

  1. With the ring section view active, click Create Hole in the toolbar.
  2. Click the collar point (where the hole starts — typically on the Collar DTM surface).
  3. Click the toe point (where the hole ends — typically on the Target DTM surface).
  4. BlastCAD computes the dip, azimuth, length, and dump angle automatically.

Delay Assignment

After holes are created, assign delays via the Tie-up workflow:

  1. Click Assign Delays in the top bar.
  2. Choose the delay pattern:
    • Chevron — delays increase from center holes outward (fan pattern)
    • Zigzag — alternating delay increment across the ring
  3. Set the base delay for the first ring and the inter-ring interval (ms).
  4. Click Apply to All Rings to batch-assign delays across the entire blast.

Ripple update: If you adjust a delay on one hole, all subsequent delays in the pattern can automatically ripple forward to maintain timing intervals.

Visualizing the Completed Design

Once all rings and holes are placed:

  • Switch to 3D view to inspect the full blast geometry.
  • Toggle Show Ring Lines to see ring plane boundaries.
  • Toggle Show Delay Labels to verify the firing sequence visually.
  • Open Statistics to run the blast analytics report.
  • Use the Proximity Circle Editor in the Charge Panel to verify burdens.

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