To determine whether the dimensions of a rock drilling jumbo perfectly match the tunnel's cross-sectional dimensions, you should check the following points step by step:
1. Confirm the tunnel cross-section parameters
Obtain the design drawings of the tunnel and clearly define:
Tunnel width (bottom and maximum width)
Tunnel height
Tunnel shape (horseshoe, circular, rectangular, etc.)
Arch radius and sidewall curvature
Construction clearance requirements (safety margin)
These values form the baseline envelope the jumbo must fit into.
2. Check the rock drilling jumbo's overall dimensions
From the manufacturer's technical data, confirm:
Overall width, height, and length
Minimum operating height
Turning radius
Transport width (important for access tunnels)
👉 The jumbo's overall height and width must be smaller than the tunnel profile, with enough clearance for safe operation.
3. Verify boom coverage against tunnel profile
This is the most critical step.
Check:
Maximum drilling height of the boom
Maximum horizontal reach
Drilling coverage width
Ability to drill the crown, shoulders, sidewalls, and invert
A properly matched jumbo should:
Cover 100% of the excavation profile
Reach the arch and corners without repositioning or extreme boom angles
Avoid blind zones near the tunnel contour
4. Compare propulsion beam (feed) length with hole depth
Ensure:
Feed length ≥ designed blast hole depth
Feed can drill at required angles (fan-shaped or parallel holes)
No interference between feed, tunnel wall, or arch
For example:
4.5 m tunnel advance → ≥ 4.8–5.0 m feed length is recommended
5. Check clearance during operation
Allow safe clearance for:
Boom swing and rotation
Operator cabin or remote-control visibility
Ventilation ducts, lighting, and cable trays
A typical safety clearance:
≥ 300–500 mm between the machine and tunnel wall/arch
6. Simulate or overlay profiles (best practice)
The most reliable method is:
Overlay the jumbo working envelope onto the tunnel cross-sectional drawing
Or use 3D simulation / CAD comparison
If the boom envelope fully covers the tunnel profile without interference, the match is correct.
7. Field verification (on-site confirmation)
Before full operation:
Drive the jumbo into the tunnel
Perform trial positioning and boom extension
Confirm no collision, blind spots, or insufficient reach
If you want, you can tell us:
Tunnel cross-section size (width × height)
Tunnel type (hydropower, railway, mine, etc.)
Single-arm or double-arm jumbo
We can help you verify the match or recommend a suitable jumbo configuration.
