Deep geological core drilling faces harsh working conditions, including muddy mountain roads, hard fractured rock formations and long-term heavy-duty continuous operation. Kilometer-class full hydraulic core drilling rigs are prone to various malfunctions. Timely troubleshooting and systematic routine maintenance can greatly reduce downtime, extend equipment service life, and guarantee stable construction for 1000–1400m ultra-deep boreholes. Based on field application experience of Xingda XDX-6 crawler full hydraulic core drilling rig, we summarize frequent on-site failures, causes, solutions and full-cycle maintenance standards as follows.

I. Common On-site Malfunctions, Causes & Troubleshooting

1. Excessively fast hydraulic oil temperature rise & high oil temperature

Symptoms: Hydraulic oil heats up rapidly after 1–2 hours of continuous drilling, accompanied by power reduction, weak rotation and slow feeding/lifting speed. Causes: Improper hydraulic oil volume; radiator clogged with dust, mud and gravel; deteriorated hydraulic oil with unqualified viscosity; minor hydraulic line leakage leading to abnormal system pressure; prolonged full-load deep drilling exceeding heat dissipation limit. Solutions: Shut down for cooling; clean radiator surface; adjust oil level or replace hydraulic oil with factory-specified grade; fasten leaking joints and repair oil seals.

2. Insufficient rotary torque, slipping drilling & slow penetration rate

Symptoms: Low drilling efficiency in hard/fractured strata, idle rotation without penetration. Causes: Improper system pressure setting, worn relief valve causing pressure loss; internal wear of hydraulic main pump reducing volumetric efficiency; worn drill pipe threads, deteriorated DTH hammer; excessive cuttings accumulation in borehole. Solutions: Calibrate working pressure; overhaul main pump and relief valve; inspect and replace worn drilling tools; flush borehole regularly to discharge cuttings.

3. Stuck tripping, excessive resistance during hoisting and lowering drill string

Symptoms: Difficult hoisting and lowering above 800m deep. Causes: Borehole collapse, fallen rock fragments and accumulated cuttings; bent drill pipes; insufficient lubrication on mast slide rails; frayed or disordered winch wire rope. Solutions: Flush borehole thoroughly to stabilize wall; straighten or replace deformed drill pipes; lubricate slide rails; arrange wire rope properly and replace it once wear exceeds standard.

4. Crawler traveling faults: deviation, weak traction & slipping

Causes: Mud trapped between crawler tracks; inconsistent track tension; leakage of travel hydraulic motor and insufficient pressure; rusted rollers lacking lubrication. Solutions: Clean mud inside tracks; adjust left and right track tension evenly; repair travel motors; fill grease for wheel assemblies regularly.

5. Low core recovery rate, core jamming & blockage

Causes: Improper core catcher and barrel for fractured strata; excessively fast drilling speed disturbing rock formation; unreasonable flushing fluid flow rate. Solutions: Adopt matched core tools; slow down penetration speed; adjust flushing liquid flow to stabilize borehole wall and improve core recovery.

II. Standard Phased Maintenance Procedures

1. Pre-shift Daily Inspection (10 minutes compulsory)

1. Check diesel engine oil, coolant and hydraulic oil level; observe hydraulic oil for emulsification or turbidity;
2. Inspect radiator and dust screen for blockage; track tension and wire rope abrasion;
3. Apply lubricating grease to mast slide rails, winch bearings and rotary mechanism;
4. Check all pipe joints and oil seals for leakage; run idle for 3–5 minutes for preheating.

2. Post-shift Daily Maintenance

1. Wash mud, rock dust and debris off the machine body, radiator and crawlers with high-pressure water to prevent component corrosion;
2. Retract mast, release track tension and relieve residual hydraulic pressure;
3. Check drill pipe thread wear, apply thread compound and store properly;
4. Inspect the frame for collision cracks and loose bolts, tighten timely.

3. Periodic Scheduled Maintenance (based on working hours)

1. Every 250 working hours: Replace diesel filter, engine oil filter and air filter; check hydraulic oil cleanliness;
2. Every 500 working hours: Fully replace hydraulic oil and hydraulic filter; overhaul relief valve and main hydraulic pump; calibrate system pressure;
3. Every 1000 working hours: Disassemble and inspect rotary assembly, winch unit and travel motors; check mast welding seams and structural strength;
4. Rainy seasons & humid southern mountainous areas: Shorten maintenance cycles with priority on rust prevention, waterproofing and dustproofing.

III. Significance of Scientific Maintenance

The XDX-6 full hydraulic core drilling rig is designed for kilometer-scale deep mineral exploration, hydrogeological and geothermal drilling with heavy loads and harsh environments. Proper maintenance avoids severe accidents such as drill sticking, pipe burst and hydraulic system failure, ensures continuous stable operation for 870m, 1400m ultra-deep boreholes, cuts maintenance costs and construction delays. Hubei Xingda provides customers with official maintenance manuals, remote technical support and customized maintenance plans tailored for complex strata in Hunan and southwest mountainous regions. With comprehensive after-sales service, we support efficient delivery of geological exploration projects nationwide.