421TA DTH Drilling Rig for an African Quarry Blasting Project
Project Background
An African quarry contractor required a mobile DTH drilling rig for production blasting in a hard-rock quarry. The project involved drilling blasting holes on open quarry benches, where the contractor needed stable drilling performance, reliable cuttings removal, and good mobility between drilling locations.
The main drilling requirement was a hole diameter of approximately 90–127 mm, with individual blast holes reaching depths of up to around 20 m. The quarry working area included uneven terrain, so the drilling equipment needed sufficient off-road capability while maintaining stable drilling performance.
Based on the project requirements, the RUIXIN 421TA DTH drilling rig was selected as the equipment configuration for the application. The model is designed for Φ90–127 mm drilling and has a maximum listed drilling depth of 21 m. Its integrated configuration combines the drilling system and air-compression system, making it suitable for surface blasting applications in quarries and open-pit mining.
Project Requirements and Constraints
The quarry contractor identified several key requirements before selecting the drilling equipment:
- Hard-rock formation: The rig needed sufficient percussion and rotary drilling capability for quarry rock.
- 90–127 mm hole diameter: The drilling system needed to cover the required blasting-hole range.
- Up to 20 m hole depth: The equipment needed sufficient feed and drilling capability for production blasting.
- Uneven quarry terrain: The rig needed good mobility and off-road capability.
- Dust control: Effective removal of drilling dust and cuttings was required during continuous drilling operations.
These requirements made a mobile surface DTH drilling rig more appropriate than a conventional small rock drilling machine.
Why the 421TA DTH Drilling Rig Was Selected
The 421TA was selected based on the combination of drilling diameter, drilling depth, power, mobility, and integrated air-compression configuration.
1. Suitable Drilling Diameter
The 421TA supports a drilling-hole diameter of Φ90–127 mm, covering the required range for the quarry’s blasting operation. The standard configuration uses a 3.5-inch DTH hammer and Φ60 × 3,000 mm drill rods.
For quarry blasting, the drilling diameter needs to be matched with the bench height, rock characteristics, blasting pattern, and explosive loading requirements. A 90–127 mm range gives the contractor flexibility to adjust the drill-bit configuration according to different blasting designs.
2. 21 m Maximum Drilling Depth
The 421TA has a listed maximum drilling depth of 21 m, which matches the project’s requirement for approximately 20 m blasting holes.
This provides a reasonable working margin without selecting a significantly larger machine designed for much deeper drilling.
3. 162 kW Diesel Power
The machine uses a Yuchai 162 kW diesel engine, providing power for the drilling, hydraulic and air-compression systems. The relatively high power output is suitable for demanding surface drilling conditions where the machine must operate independently at quarry sites.
4. Integrated Air-Compression System
One of the practical advantages of this configuration is the integrated air-end system. The 421TA uses a larger two-stage screw air end and is designed around high-pressure air drilling requirements.
Because DTH drilling depends on compressed air to drive the hammer and remove cuttings, the compressor and DTH hammer need to be matched as a complete system.
For this project, the integrated configuration simplified equipment matching and reduced the need for the customer to arrange a separate compressor system.
5. Mobility on Uneven Quarry Terrain
The quarry required frequent movement between drilling locations. The 421TA is designed as a mobile surface drilling rig with off-road capability and a relatively compact overall configuration.
Its published dimensions are 7,480 × 2,300 × 2,750 mm, with a machine weight of approximately 7,560 kg.
The machine also uses a dual-speed tramming system and an oscillation-cylinder design intended to improve movement and stability on uneven terrain.
Project Equipment Configuration
| Item | 421TA Configuration |
|---|---|
| Application | Quarry blasting |
| Drilling Method | DTH |
| Hole Diameter | Φ90–127 mm |
| Maximum Hole Depth | 21 m |
| Standard DTH Hammer | 3.5 inch |
| Drill Rod | Φ60 × 3,000 mm |
| Engine | Yuchai, 162 kW |
| Maximum Rotation Torque | 1,500 N·m |
| Machine Weight | 7,560 kg |
| Dimensions | 7,480 × 2,300 × 2,750 mm |
The final drill-bit and DTH hammer selection should still be adjusted according to the actual rock hardness, hole diameter, drilling depth and blasting design.
How the DTH Drilling Rig Was Used
The typical drilling cycle at the quarry was organized as follows:
Positioning → Hole alignment → Collar drilling → DTH drilling → Cuttings removal → Drill rod extension → Target depth → Hole cleaning → Rig relocation
After positioning the 421TA at the designated drilling point, the operator adjusted the drilling direction according to the blasting-hole layout.
The DTH hammer then delivered percussion energy directly at the bottom of the borehole while compressed air helped remove rock cuttings.
Once the required depth was reached, the operator completed hole cleaning before moving the rig to the next drilling position.
This operating method is particularly suitable for hard-rock quarrying because the DTH hammer works directly at the bottom of the hole, while compressed air provides both hammer operation and cuttings removal.
Delivery and Commissioning
The equipment delivery process followed a standard factory-to-site workflow:
Factory assembly → System inspection → Drilling-system testing → Air-system inspection → Final quality check → Loading → Overseas transportation → Site commissioning
Before shipment, the drilling rig was inspected for the engine, hydraulic system, rotary system, feed beam, crawler/tramming system and drilling components.
The DTH drilling tools and related accessories were also prepared according to the customer’s drilling requirements.
After arrival at the quarry, commissioning focused on checking the hydraulic system, drilling rotation, feed movement, air system and DTH hammer operation before production drilling began.
Project Results
The 421TA configuration provided the quarry contractor with a drilling system matched to the project’s Φ90–127 mm blasting-hole requirement and approximately 20 m hole depth.
The main application benefits included:
- Suitable drilling range for quarry blasting
- Integrated air-compression configuration
- Strong diesel power for surface drilling
- Mobile design for movement between drilling locations
- DTH drilling capability for hard-rock formations
- Flexible drill-bit configuration for different blasting requirements
Actual penetration rate, daily drilling footage and drill-tool consumption depend on rock hardness, hole diameter, drilling depth, operator experience and site conditions. Therefore, production performance should be evaluated according to the specific quarry conditions rather than using a fixed drilling-output figure.
What This Case Shows
This project demonstrates why selecting a DTH drilling rig should be based on the complete drilling requirement rather than a single specification.
For quarry and open-pit blasting applications, buyers should evaluate:
- Required hole diameter
- Hole depth
- Rock hardness
- Bench height
- Required daily drilling volume
- DTH hammer size
- Compressor air pressure and flow
- Machine mobility
- Dust-collection requirements
- Transportation and site conditions
The 421TA is one option within RUIXIN’s DTH drilling-rig range. The current product range also includes models for different hole-diameter requirements, including 420B-1, 452H, 452T, 453TC, 454T, 454G and 845-1.
Case Keywords
DTH drilling rig
DTH drill rig for quarry
African quarry drilling rig
surface DTH drilling rig
blasting hole drilling rig
open-pit mining drilling rig
CTA
Have a quarry or open-pit drilling project? Send us your required hole diameter, drilling depth, rock hardness and working conditions. RUIXIN engineers can recommend a suitable DTH drilling rig, hammer and drilling configuration for your project.
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