The UD391 is a compact and flexible single-boom electro-hydraulic tunneling drill rig for excavation in underground mine roadways and engineering construction tunnels, with a working cross-section up to 36 m².

Equipped with a 20 kW Sandvik LD60 hydraulic rock drill, the UD391 achieves higher and stable penetration rates and extended drill tool service life in various rock formations. The robust LG-B26F drill boom features 360° rotation of the feed beam and excellent automatic leveling function, together with larger and optimized cross-section coverage. It enables fast, stable and precise tunneling drilling, as well as drilling operations for a wide range of other applications. The LG-THC rock-adaptive drilling control load-sensing hydraulic system with piston pump and automatic control functions allows operators to concentrate on safe, rapid and accurate drilling while ensuring low drill tool consumption.

The UD391 is fitted with a high-power diesel engine, heavy-duty four-wheel drive, articulated steering and FOPS safety canopy. The overall layout of the drill rig balances driving stability and operator visibility when traveling in narrow roadways and engineering tunnels. The rig is easy to operate and maintain, and all routine maintenance can be performed at ground level.