Core Drilling Rig Mistakes: How to Avoid Sample Contamination & Deformation

II. Sample Deformation: These "violent operations" directly ruined the samples.
Error 1: Improper drilling parameters, excessive disturbance of the geological formation

Harm: Excessive drilling pressure and rotation speed lead to deformation of soft soil due to compression and fracturing of hard rock;Common mistakes by beginners: To increase speed, high rotation speeds (>150 r/min) are still used in hard rock formations, and excessive pressure is applied in soft soil formations (drilling pressure > 10 kN);
Correct practice: Use parameters adapted to the geological formation (clearly specified in our Xinhao core drilling machine operation manual): soft soil drilling pressure 5-8 kN, rotation speed 40-60 r/min; hard rock drilling pressure 12-18 kN, rotation speed 80-100 r/min; use spiral or thin-walled core barrels to reduce friction and disturbance to the sample.

Error 2: Rough drilling and core extraction actions, leading to sample detachment and fracture

Harm: Rapid lifting of the drill rod and forceful tapping of the core barrel lead to scattering of soft soil samples and fracturing of hard rock cores;
Correct practice: Lift the core barrel at a speed ≤0.2 m/min, maintaining a uniform and steady speed; when removing the sample, gently tap the end of the core barrel with a rubber hammer (do not use an iron hammer), or slowly blow it out from the bottom with high-pressure air, avoiding violent disassembly.

Error 3: Improper storage and transportation, leading to sample deformation

Harm: Samples are not sealed and are stacked during storage, leading to cracking of soft soil and scattering of broken samples;
Correct practice: Soft soil samples should be sealed within 2 hours after removal and placed in a refrigerated box (temperature 5-10℃) to prevent cracking; hard rock cores should be fixed in the core box with foam pads, and violent shaking should be avoided during transportation; our Xinhao hydraulic core drilling rig's matching sample boxes have a shock-absorbing design, which can effectively protect the samples.

III. Core Sampling Summary for Beginners (Compiled by our Xinhao Construction Team)

Cleanliness: Core sampling tools, operating environment, and contact tools must be clean to prevent cross-contamination;

Gentle Handling: Drilling, lifting, and core retrieval should be performed slowly, steadily, and gently throughout the entire process to minimize human disturbance;

Labeling: Samples should be clearly labeled immediately after sampling to avoid confusion;

Appropriate Selection: Choose the correct core sampling tools and parameters according to the geological formation, avoiding blind acceleration and excessive pressure.

In fact, geological exploration sampling is not difficult. As long as you avoid these mistakes and follow our Xinhao core drill machine's operating instructions step by step, you can obtain complete and accurate samples. If this is your first time operating the equipment, it is recommended to practice under the guidance of a professional to familiarize yourself with the equipment characteristics before working independently!