Integrated Dig‑bolt Drill Rod
Also referred to as integrated drilling-bolting anchor rod, the integrated dig‑bolt drill rod for bolter miner is specially designed to match the on-board roof bolter of bolter miners.
- Product Introduction
Also referred to as integrated drilling-bolting anchor rod, the integrated dig‑bolt drill rod for bolter miner is specially designed to match the on-board roof bolter of bolter miners. It integrates three functions-drilling rod, supporting anchor bolt and grouting channel-into a single rod piece. One single rod can sequentially complete three working procedures: borehole drilling, grouting anchoring and pre-tension support. It replaces the segmented operation mode of the traditional process: drilling with ordinary drill rods, pulling out rods, loading anchoring agents, and replacing with anchor bolts for stirring. As a core consumable, it enables parallel rapid excavation and support in coal roadways.
Structural Composition (Integrated Non-spliced Design)
Integrated Front Bit
Cemented carbide bits are brazed firmly onto the hollow rod body without intermediate adapter joints. Small grout/water outlet holes are machined on the bit. During drilling, water and compressed air remove cuttings; during grouting, anchoring agent flows from the borehole opening to the hole bottom and overflows backward for denser anchoring.
High-Strength Hollow Rod Body (Core Main Component)
Made of quenched and tempered alloy seamless steel pipe with a full central through hole. During drilling, high-pressure water or compressed air is delivered through the hole to cool tools and flush out cuttings. During anchoring, resin anchoring agent and grout are pumped through the channel. Continuous left-hand threads or spiral ribs are rolled on the outer wall of the rod body to assist cuttings discharge while drilling and boost interlocking friction with surrounding rock after anchoring.
Multi-Functional Integrated Tail Joint
Monolithically forged, the mainstream structure combines a square drive shank and an integrated multi-purpose nut. The square section fits the clamp of the bolter miner's on-board drill rig to transmit torque. The matched special nut integrates sealing, locking and pre-tension functions. Reverse rotation of the rod performs drilling, while forward rotation tightens the nut to apply pre-stress support, eliminating the need for separate stirrers or adapter sleeves.
Surface Strengthening Treatment
The entire rod undergoes quenching and tempering plus anti-rust phosphating treatment to adapt to underground environments with high humidity, heavy dust and corrosive media.
Working Principle (Three-in-One Operation Logic)
Reverse Rotation Drilling Stage
The on-board drill rig clamps the tail of the integrated rod and drives it to rotate reversely. The front bit cuts coal and rock strata, while outer-wall threads push coal dust outward. Water or compressed air is fed through the hollow through hole to clean the borehole, completing hole forming in one pass without rod replacement.
Hole-Bottom Grouting & Anchoring Stage
Once drilling reaches the designed depth, two-component resin anchoring agent is pumped through the hollow channel of the rod. The agent sprays out from small holes on the bit, mixes at the hole bottom and fills gaps inside the borehole to adhere tightly to the hole wall and cure for anchoring.
Forward Rotation Pre-Tension Support Stage
The drill rig switches to forward rotation to tighten the multi-functional tail nut, pressing the pallet closely against the rock surface and applying the designed pre-stress directly. The rod remains permanently inside the borehole as a supporting anchor bolt, realizing drilling, grouting, anchoring and tensioning all with one single rod.
Core Advantages (vs. Separate Drill Rod & Anchor Bolt Scheme)
Improved Safety & Efficiency with Streamlined Procedures
The traditional 6-step process is simplified to one single operation. It eliminates high-risk manual work including drill rod extraction, manual anchoring agent loading and secondary anchor bolt insertion. The operation time for a single anchor bolt is cut by over 40%. It matches the rhythm of parallel excavation and support of bolter miners, supporting rapid tunneling with daily advance up to hundreds of meters.
High Structural Strength & Low Failure Rate
The rod body, bit and joint are integrated via welding and forging, eliminating risks of loose connecting sleeves or joint fracture. The square tail withstands high torque output from bolter miner on-board drills and resists bending or breaking under heavy-load drilling.
Stable & Controllable Anchoring Quality
Anchoring agent fills the borehole outward from the bottom, leaving no empty cavities at the hole mouth and ensuring full, uniform anchoring sections. The integrated rod is never pulled out during construction, avoiding anchoring failure caused by hole collapse or shrinkage. It delivers excellent performance in soft coal seams and fractured roof strata.
Compatible with Intelligent Equipment
It can connect with automatic anchor bolt silos and manipulator rod feeding mechanisms of bolter miners to realize low-manpower operation, meeting the requirements of intelligent mine construction.
Mainstream Specifications & Matched Equipment
Common outer diameters of hollow integrated rods: φ22 mm, φ25 mm, φ28 mm;
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Standard single lengths: 1.2 m, 1.8 m, 2.4 m, 2.8 m. Extension-type integrated rods are available for extra-long roadways;
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Matched equipment: Domestic and imported bolter miners including Hengshuo Machinery, Sandvik MB670, Sany Heavy Equipment and other models for on-board roof and rib bolters;
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Matching bits: PDC composite cutter bits for hard rock, cemented carbide coal bits for soft coal seams, selectable on demand.
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Typical Application Scenarios
Rapid tunneling of long-distance coal roadways in coal mines
Synchronized support for roof and ribs in thick coal seams, soft outburst-prone coal seams and fractured roof roadways;
Parallel excavation and bolting in semi-coal-rock roadways
Coordinates cutting and support, controls exposed roof span and reduces roof caving risks;
Integrated probing and grouting operations
Direct anchoring and hole sealing after constructing advance water drainage holes and gas pressure relief holes, enabling multi-purpose single boreholes;
High-gas coal mines
The hollow channel can double as a gas drainage passage to integrate rock support and gas control.
Operation, Maintenance & Selection Precautions
Store rods on raised supports underground for moisture resistance to prevent rust blockage of the hollow through hole from water intrusion;
Avoid impact deformation of the tail square section, which will cause slippage of drill rig clamps and insufficient torque transmission;
Select thick-walled quenched and tempered models for hard rock working conditions to prevent bending under high-torque drilling;
Clean bit grout outlets before grouting to avoid anchoring agent backflow caused by coal dust blockage;
Forbid reusing the integrated rod as an extendable drill rod by repeated pulling out, as the rod is a disposable supporting component.
Key Differences from Conventional Separate Drill Rods for Bolter Miners
| Comparison Item | Integrated Drill Rod | Ordinary Separate Drill Rod (Smooth / Spiral Drill Rod) |
| Final Purpose | Remains in borehole after drilling as permanent anchor bolt | Must be pulled out upon hole completion; separate anchor bolt is lowered later for support |
| Number of Procedures | One rod completes drilling, grouting, anchoring and tensioning | Two sets of consumables (drill rod + anchor bolt) with multiple procedure switches |
| Suitability for Weak Surrounding Rock | Excellent; prevents hole collapse with full anchoring filling | Hole collapse easily occurs during rod extraction in fractured strata, leading to unstable anchoring quality |
| Labor Intensity | Low; automatic rod feeding via manipulators available | High; manual replacement of drill rods and loading of anchoring agents required |
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