The KJ422 Hydraulic Underground Drill Rig is a high-performance twin-boom jumbo engineered for demanding underground mining and tunneling applications. Equipped with advanced hydraulic rock drills, precise boom positioning systems, and a robust articulated chassis, the machine delivers exceptional drilling speed, accuracy, and reliability in medium to hard rock formations. The dual-boom configuration enables simultaneous drilling operations, maximizing productivity while reducing excavation time and operating costs. Designed for large tunnel sections and intensive underground development projects, the KJ422 is an ideal solution for mine development, tunnel excavation, hydropower construction, underground infrastructure projects, and other high-efficiency rock drilling applications.
Quzhou Mazellion Heavy Industry Technology Co., Ltd. is a professional manufacturer of diesel screw air compressors and mining drilling equipment, serving global mining, quarry, water well drilling, and construction projects. We provide factory-direct supply, stable quality, and full OEM customization to help customers win local markets with better cost performance and reliability.
To start cooperation: send your inquiry → get a tailored technical solution & quotation → confirm order → production & testing → fast shipment → long-term spare parts & technical support. We respond quickly and support you throughout the whole project.
Drilling Rig Specification Table
Dimensions and Weight
| Parameter | Specification |
| Length | 15000 mm |
| Width | 2550 mm |
| Height | 2400 / 3100 mm |
| Weight | Approx. 28000 kg (excluding the workbench) |
| Tramming speed on flat ground | 10 km/h |
| Maximum climbing capacity | 25% (14°) |
Safety Protection
| Parameter | Specification |
| Noise level | < 100 dB(A) |
| Lifting safety roof | FOPS & ROPS certified |
Air & Water System
| Parameter | Specification |
| Air compressor | DLGF 1.5/8-11(B) |
| Capacity of air compressor | 1.55 m³/min |
| Pressure | 8 bar |
| Device of shank lubrication | Electronic pulse lubrication pump |
| Air consumption of lubrication | 2 × 0.3 m³/min |
| Oil consumption of lubrication | 2 × 180-250 g/h |
| Power of water pump | 7.5 kW |
| Capacity of water pump | 10 m³/h |
Chassis
| Parameter | Specification |
| Diesel engine | Cummins QSB5.9-C160, 119 kW / 2200 rpm |
| Drive system | Hydraulic torque converter + gearbox |
| Travelling braking | Wet bridge brake |
| Parking braking | Mechanical brake |
| Fuel tank | 120 L |
Drilling System
| Parameter | Specification |
| Rock drill | 2 × HC95LMH / RD22U |
| Rod size | R38 / T38 |
| Impact power | 21 kW / 22 kW |
| Impact frequency | 62 Hz / 53 Hz |
| Hole diameter | Ø42-102 mm |
| Beam rotation | 360° |
| Feed extension | 1600 mm |
| Model of drill boom | K50 |
| Form of drill boom | Self-leveling |
| Boom extension | 2500 mm |
Electric Hydraulic Power Unit
| Parameter | Specification |
| Motor | 2 × 75 kW |
| Pump Type | Axial variable displacement piston pump |
| Rotation | Gear pump |
| Filter fineness | 10 μ |
| Hydraulic oil tank | 400 L |
| Hydraulic cooler | Water cooler |
| Working voltage | 380 V |
| Frequency | 50 Hz |
| Starting method | Star-triangle |
| Cable specifications | 3 × 120 + 3G25 |
1. High-Production Underground Mining Operations
Designed for large-scale underground gold, copper, iron ore, zinc, and nickel mines requiring rapid tunnel development. The twin-boom drilling system significantly increases drilling productivity and shortens mine development cycles.
2. Large Cross-Section Tunnel Excavation
Ideal for underground drifts, haulage tunnels, transportation galleries, and ventilation tunnels with medium to large cross-sections. The extended boom coverage enables efficient full-face drilling with minimal machine repositioning.
3. Railway and Highway Tunnel Construction
Widely used in drill-and-blast excavation for railway tunnels, highway tunnels, and mountain crossing projects. The precise hydraulic control system ensures accurate hole alignment and high-quality blasting results.
4. Hydropower and Underground Cavern Engineering
Suitable for powerhouse caverns, water diversion tunnels, surge chambers, and underground hydroelectric infrastructure projects where reliable drilling performance and high excavation efficiency are essential.
5. Underground Infrastructure Development
Applicable to metro tunnels, utility tunnels, underground storage facilities, defense engineering, and municipal underground construction projects requiring fast and accurate rock drilling operations.
6. Hard Rock Excavation and Ground Support
Engineered for medium-to-hard rock formations, the KJ422 can perform face drilling, perimeter hole drilling, cut hole drilling, and rock bolt hole drilling, providing a complete solution for excavation and ground support applications.
Promote 360° beam rotation and automatic leveling
Powerful four-wheel drive articulated chassis
Spacious working area with good visibility
Q1: What kind of underground projects is the KJ422 suitable for?
The KJ422 is designed for underground mining and tunneling applications. It is suitable for metal mines, non-metal mines, hydropower tunnels, railway tunnels, highway tunnels, underground infrastructure projects , etc. The machine is ideal for tunnel sections ranging from 16 m² to 95 m² and can perform both face drilling and rock bolting operations.
Q2:Why choose your company?
We are a professional manufacturer specializing in underground drilling and mining equipment with extensive export experience.
Our advantages include: Strict quality control ,Competitive factory-direct pricing, Global after-sales support, Fast spare parts supply, Professional technical team, Rich experience in mining and tunneling projects.
Our equipment has been exported to Southeast Asia, South America, Africa, Central Asia, the Middle East, and Europe, serving customers in mining, quarrying, and underground construction industries worldwide.
Q3:Can the machine be customized?
Yes. We offer customization options including:Engine brands, Hydraulic components, Electrical systems. OEM and ODM services are available for distributors and project contractors.
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