Pneumatic Rock Drill (Jackleg) Specifications
The figures below describe typical industry specifications for this class of equipment rather than a single fixed model. Use them to scope a requirement, then confirm exact figures against the supplied unit before purchase.
| Specification | Typical value |
|---|---|
| Hole diameter | 32–45 mm typical |
| Hole depth per steel | 0.8–3.2 m in 0.8 m increments |
| Air consumption | 100–150 cfm (2.8–4.2 m³/min) at 6–7 bar |
| Steel | Hex 22 mm or 25 mm, integral or tapered |
| Bit | Carbide chisel or button, 34–41 mm |
| Mass | 25–45 kg plus pusher leg |
| Lubrication | Inline air-line oiler, mandatory |
| Water | Front-head water flushing to suppress dust |
| Noise | 110–120 dB(A) at the operator; hearing protection mandatory |
What a Pneumatic Rock Drill (Jackleg) Is Used For
- Development blasting rounds in small shafts and drives
- Production drilling on narrow veins
- Secondary blasting of oversize
- Anchor and utility holes underground
Maintenance Schedule
Most premature failures in this equipment class trace back to a missed routine check rather than a design fault. The intervals below are a practical starting schedule; adjust them to your duty cycle and the manufacturer manual.
| Interval | Task |
|---|---|
| Every shift | Fill the air-line oiler; inspect hoses, water tube and steel threads; check the leg for smooth travel. |
| Daily | Flush the drill with oil at knock-off; inspect chuck bush and rotation pawls. |
| Weekly | Strip front head if rotation is sticky; inspect rifle bar and piston. |
| On failure to rotate or hammer | Usually dry running (no oiler) or worn chuck. Do not keep running a dry drill — it seizes. |
Frequently Asked Questions
How much compressor do four jacklegs need?
100–150 cfm each, plus leakage and diversity. Four drills working together need about 500–600 cfm at 6–7 bar at the face, not 400. Undersized air is the usual reason penetration drops and steels stick. See the mining air compressor page for the other half of this specification.
Jackleg, stoper or sinker?
Jackleg (pusher-leg) for drifting and inclined holes. Stoper (uphole) for raising and roof holes. Sinker for downward holes in shafts. They are different machines; a jackleg used as a stoper wrecks the miner and the hole. Specify the duty.
Why is water flushing mandatory?
Because dry drilling in silica ore produces respirable crystalline silica, which causes silicosis. Water through the steel knocks the dust down at the hole. Dry drilling is still seen on Tanzanian small mines and is one of the most damaging shortcuts in the industry.
Supply and Delivery Across Tanzania
Bart Mining supplies pneumatic rock drill (jackleg) and related equipment to mining operations throughout Tanzania, with primary coverage of the Lake Victoria Goldfields (Mwanza, Kahama, Geita, Shinyanga and Bukombe), alongside the Lupa Goldfields around Chunya and Mbeya, and delivery nationwide from Dar es Salaam.
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Need a pneumatic rock drill (jackleg) specified for your site?
Tell us your duty, depth or throughput and available power supply. We will come back with a specification and price, and flag anything on site that needs to change to make it work.