Charge Templates & Drill Templates
Templates encode repeatable engineering decisions into reusable configurations, eliminating repetitive manual entry across similar holes and rings.
Table of contents
Charge Templates
A Charge Template defines a complete explosive column layout — the ordered sequence of segments that will be applied to a hole when the template is used.
Template Structure
Each template contains:
| Field | Description |
|---|---|
| Name | Template identifier (e.g., “Standard 89mm Emulsion”, “Decked ANFO Ring”) |
| Description | Optional notes about the intended use case |
| Segments | Ordered list of charge segments (see below) |
| Toe Stemming (m) | Length of stemming placed at the hole toe before the first explosive segment |
| Collar Stemming (m) | Length of stemming placed above the last explosive segment |
Defining Segments
Each segment in the template has:
| Field | Options | Description |
|---|---|---|
| Type | explosive, stemming, air_deck | Segment material type |
| Length (m) | Numeric | Absolute length of this segment within the hole |
| Explosive Name | From Explosives DB | The product to use (must exist in your Explosives database) |
Example: Simple Bottom Emulsion Charge
Name: Standard 89mm Emulsion
Collar Stemming: 1.5 m
Segments:
1. Explosive — 4.0 m — "Emulsion 1.0"
Toe Stemming: 0.0 m
Example: Decked Charge with Air Gap
Name: Decked Ring — ANFO + Air Deck
Collar Stemming: 1.5 m
Segments:
1. Stemming — 1.0 m — (inter-deck stemming)
2. Air Deck — 0.5 m
3. Explosive — 2.5 m — "ANFO 0.8"
4. Explosive — 2.5 m — "ANFO 0.8"
Toe Stemming: 0.0 m
Scaling Behaviour
When a template is applied to a hole, BlastCAD scales the proportions of segments to fit the available charge length:
\[L_{seg,actual} = L_{seg,template} \times \frac{L_{charge,hole}}{L_{charge,template}}\]This ensures the stemming ratios and deck ratios are preserved even when the hole depth differs from the template design depth. Toe and collar stemming lengths are not scaled — they remain as absolute values.
Creating and Managing Charge Templates
- Database Manager → Charge Templates tab.
- Click New Template to create a template.
- Add segments using the Add Segment button — drag to reorder.
- Click Save.
Templates can be:
- Duplicated — right-click → Duplicate, then modify.
- Exported — as JSON for sharing with other BlastCAD accounts.
- Imported — from a JSON file.
Drill Templates
A Drill Template defines the geometric arrangement of holes within a ring plane. Instead of manually placing each hole, the template describes hole positions relative to the ring’s pivot point.
Template Structure
| Field | Description |
|---|---|
| Name | Template identifier (e.g., “5-hole Fan”, “7-hole Radial”) |
| Burden | The design burden this template was built for (m) — used for burden-based spacing checks |
Each hole in the template is defined by:
| Field | Description |
|---|---|
| Type | reamer or easer |
| dX | Horizontal offset from ring pivot in the ring plane (m) |
| dY | Vertical offset from ring pivot in the ring plane (m) |
| Diameter | Hole diameter for this position (mm) |
| Ring Index | The ring number this hole belongs to (for multi-ring templates) |
Hole Types
| Type | Description |
|---|---|
reamer | Large-diameter relief hole (no explosive) — provides a free face for adjacent holes |
easer | Standard production hole — charged and fired |
Example: Simple 5-Hole Fan
Name: 5-hole Fan 89mm
Burden: 2.0 m
Holes:
1. easer — dX: -2.0, dY: 0.5, Ø 89mm
2. easer — dX: -1.0, dY: 1.5, Ø 89mm
3. easer — dX: 0.0, dY: 2.0, Ø 89mm ← crown hole
4. easer — dX: 1.0, dY: 1.5, Ø 89mm
5. easer — dX: 2.0, dY: 0.5, Ø 89mm
Applied at the pivot point (1.8 m above drive floor), this generates five holes fanning upward from the ring’s central axis, with toes targeting the stope hanging wall.
Applying a Drill Template
In Ring Workflow Step 4:
- Click Apply Template.
- Select a Drill Template.
- BlastCAD projects each template hole from the pivot point through the ring plane until it intersects the Target DTM surface.
- Collar and toe coordinates are assigned. Rig constraints are checked immediately.
Template Library Strategy
A well-maintained template library significantly accelerates design time. Recommended approach:
- Name templates by rig + diameter + pattern type — e.g., “Simba M6 — 89mm — 7 Hole Fan”.
- Create one charge template per explosive product per diameter — charge column proportions are diameter-dependent.
- Version templates when site parameters change — keep old templates and mark them deprecated rather than modifying in place, so historical designs can be reviewed.