Buying a core drill rig is essentially an investment in comprehensive cost per drilling meter. If you plan to recover equipment cost within 6–8 months and generate drilling revenue over three times the machine’s original value in the following two years, your most popular option among exploration teams is the NQ core drill rig for sale. Why? The NQ bore size strikes the optimal balance among three conflicting indicators: bit service life, net drilling speed, and core sample quality. Paired with wireline coring technology, you can retrieve core without pulling out the whole drill string, lifting the proportion of effective drilling time from 40% under conventional drilling to above 75%.
NQ Hydraulic Core Drilling Rig Technical Parameters
Below are the core specifications of four mainstream models covering drilling depths from 400m to 1100m. All units adopt a dual air-water cooling system and an integrated crawler-mounted mast-rig structure with remote control:
| Model | YGX-400 | YGX-600 | YGX-800 | YGX-1000 |
| Drilling Depth(M) | 180-400-500 | 200-600-650 | 400-800-1000 | 500-1000-1100 |
| Rated pressure(MPA) | 21 | 21 | 25 | 28 |
| Rated Flow(L/min) | 168 | 192 | 260 | 300 |
| Heat Dissipation Mode | Air cooling+water cooling | |||
| Engine Brand | Yuchai | Yuchai | Yuchai | Cummins |
| Rated power/speed | 78kW/ 2400r/min | 92kW/ 2400r/min | 92kW/ 2400r/min | 154kW/2400r/min |
| Drilling Angle(°) | 0-90 | 45-90 | 45-90 | 45-90 |
| Lifting Force(T) | 12 | 16 | 24 | 30 |
| Feed Force(T) | 6 | 8 | 12 | 15 |
| Hydraulic Mud pump flow | 30-90（L/min） | 30-90（L/min） | 90-180（L/min） | 90-180（L/min） |
| Hydraulic Mud pump power | 4-7(MPA) | 4-7(MPA) | 4-7(MPA) | 4-7(MPA) |
| Dimension | 4000*1900*1800mm | 4000*2000*1800mm | 5500*2100*2000mm | 6000*2200*2400mm |
| Weight | 4.3T | 4.5/5.5T | 6.5T | 7.5T |
Note: All models fit thin-wall diamond drill tools, including NQ, HQ, and BQ. For NQ specs: bit outer diameter 75.7mm, core diameter 47.6mm, drill rod outer diameter 69.9mm. It is recognized as the golden bore size, balancing high efficiency and low operating cost.
Why is NQ the Golden Standard for Global Metallic Mineral Exploration?
Among various drilling sizes, NQ (nominal OD 75.7mm) stands out for three key reasons:
- Balanced core dimension and penetration rate
NQ core diameter reaches 47.6mm, meeting grade test requirements for most metallic mines such as copper, lead-zinc, and gold. Its cutting area is around 30% smaller than HQ (63.6mm core diameter). Under identical rock hardness, bits fitted on the NQ hydraulic core drilling rig suffer less rock-breaking resistance, delivering a 15%–20% higher penetration rate versus HQ drilling.
- Well-matched drill string rigidity and depth capacity
NQ drill rod with 69.9mm OD and proper wall thickness delivers enough torsional and tensile strength for deep-hole drilling and boasts better stability than 55.6mm BQ drill rod. In field practice, NQ safely drills down to 1000–1200m, covering mainstream medium-deep exploration ranges and avoiding frequent size switching of drilling tools.
- Low transportation & logistics cost
Compared with HQ rigs requiring heavy crawler chassis and high-power power heads, the complete NQ rig weight can be controlled below 6.5 tons (e.g., YGX-800). Thanks to the integrated mast design, one flatbed truck finishes full transportation. This is vital for projects in mountainous and jungle terrain. As a premium core drilling machine for mining, it achieves a perfect tradeoff between mobility and drilling capacity, which makes NQ an industry benchmark.
Working Principle of the NQ core drill rig for sale
NQ core drill rig is a fully hydraulic rotary drilling device with four core working steps:
- Power head drives drill rod rotation
Hydraulic motors convert engine power into torque and rotating speed to spin the NQ drill rod directly via the top-drive power head. Equipped with a long-stroke guide rail and feed cylinder, it eliminates repeated rod breakout and enables steady, continuous drilling.
- Mud circulation for chip removal & bit cooling
Built-in hydraulic mud pump delivers flushing fluid (clean water or bentonite mud) from the mud tank into the inner drill rod holes. Fluid sprays out through bit nozzles, carries rock cuttings back to ground via the annular gap between drill pipe and borehole wall. NQ’s annular clearance is roughly 2.9mm, securing smooth mud backflow and reducing the risk of stuck pipe from falling rock fragments.
- Coring and core protection
Thin-wall diamond bit cuts the formation, and the intact core enters the inner core barrel inside the drill string. The 47.6mm inner space of the NQ core barrel accommodates most mineralized veins; its thin-wall design cuts torque demand and lowers overall machine vibration.
- Wireline core retrieval
Once the core barrel gets fully filled, no full tripping is needed. Special overshot matching wireline coring drill rig is lowered inside drill rod to lock inner barrel assembly and lift core to surface within minutes, drastically cutting auxiliary downtime.
4 Benefits of Using NQ core drill rig for sale
- Over 30% higher daily drilling footage
Full hydraulic stepless speed regulation, plus long-stroke top-drive design, allows continuous drilling under optimal rotating speed and feed pressure. Field mine data proves NQ Core Drill Rig with thin-wall diamond bits achieves 80–120 meters daily footage in medium-hard rock like granodiorite, doubling the output of outdated spindle rigs.
- Core recovery rate above 95%
Combined with a double-tube single-action core barrel and shock absorption parts, the NQ setup protects the core against mud erosion and mechanical fragmentation. Split tubes or triple-tube assemblies are available for fractured altered zones to secure nearly 100% core recovery.
- Excellent borehole deviation control
NQ drill string follows compact, rigid, and straight design: narrow gap between drill rod and bore plus extended pilot bit keeps hole inclination below 1° per 100 meters, fully complying with geological standards for deep-hole deflection limits.
- Fast investment payback
NQ hydraulic core drilling rig, such as the YGX-600, costs roughly 30% less than equivalent HQ rigs, with cheaper spare parts including bits and drill rods. A small exploration team completing 800 monthly drilling meters can recover the full machine investment within 6–8 months.
How Wireline Coring Boosts Daily Footage of NQ Core Drill Rig
Wireline Coring is a milestone innovation for modern core drilling, freeing the NQ hydraulic core drilling rig from repeated full tripping. Traditional coring requires pulling out hundreds of meters of the entire drill string every 1.5–3m drilling to fetch core, spending 2–4 hours per single cycle. With wireline coring drill rig technology:
- Core recovery without pulling the full drill string: Overshot is lowered by wire rope to grab the inner barrel downhole. It only takes 15–20 minutes for one full core run at 800m depth with NQ size.
- Effective drilling time rises from 40% to 75%: Over 80% tripping operations are cut, so the rig keeps cutting rock nonstop. Taking the YGX-800 hydraulic core drilling rig as an example, effective drilling hits 6 hours in an 8-hour shift for hard rock, easily hitting over 100m of daily footage.
- Extended bit service life: Bits avoid frequent collision with the borehole wall and settled cuttings during tripping, leading to even wear. A single diamond bit for NQ can drill accumulatively 300–500 meters.
Without wireline coring, NQ’s performance potential would be greatly restricted. The combination makes the NQ core drill rig for sale standard equipment for global exploration contractors.
Measures to Prevent Borehole Deviation for Deep NQ Drilling
Increasing depth, formation anisotropy, and drill rod bending easily trigger excessive hole deflection. Our YGX series controls deviation from three aspects:
- Precision power head and long guide rail
The top-drive structure acts directly on the drill rod top to eliminate the swing seen on rotary table rigs caused by long drive pipes. YGX-800 features a 5.5m long guide rail; the feed cylinder provides stable axial thrust to keep drill pressure along the designed bore axis.
- Optimized bottom hole assembly (BHA)
Install 2–3 stabilizers (reamer OD:75.8mm) matching NQ bore size at lower drill string to fill bore space and suppress lateral vibration. An extended pilot bit with a crown over 50mm in length guides the drill string to stay centered even across alternating soft-hard interbeds.
- Real-time parameter monitoring & adjustment
Integrated hydraulic pressure gauges and flowmeters help operators judge downhole conditions via feed and rotary pressure fluctuations. Once abnormal pressure indicates pending deflection, lower bit load, and raise the rotating speed to utilize the drill string self-straightening effect. Inclinometer calibration is conducted every 50 drilled meters to control deviation below 0.5°/100m.
Field practice verifies properly configured NQ hydraulic core drilling rig limits maximum deviation within 8° at 1000m depth, satisfying the national solid mineral exploration specification DZ/T 0227-2010.
From Arctic Circle to tropical rainforests, from copper mines to gold deposits, the NQ core drill rig for sale has become an industry benchmark for metallic mineral exploration thanks to its golden-size design, high efficiency from wireline coring, and stable full-hydraulic performance. Contact us right now for customized NQ drilling solutions for your project for precise, efficient, and safe drilling every time.
