1. What is Core Recovery Rate?

Core recovery rate is the most critical technical index in geological core drilling, referring to the percentage of intact rock core length obtained compared with the total drilled borehole depth. It directly reflects the authenticity and completeness of underground stratum data and serves as the core evaluation standard for qualified geological exploration projects.

A high core recovery rate means the drilled rock samples can truly restore underground stratum structure, rock properties, vein distribution and mineralization changes. For metal mines such as gold, nickel and copper, only core recovery above the industry standard can support accurate ore grade calculation, reserve verification and mine development design.

2. Why Core Recovery Rate Matters for Mineral Exploration

Guarantee Accurate Geological Data: Complete core samples ensure continuous stratum records, effectively avoiding missing thin ore veins, fractured alteration zones and key geological boundaries, which guarantees the scientificity of exploration results.

Improve Mine Investment Accuracy: Low core recovery leads to incomplete ore body data, easily causing misjudgment of ore scale, grade and burial depth. High-standard core recovery provides reliable data support for investment evaluation, mining design and risk control.

Meet Industry & Project Acceptance Standards: Formal mineral exploration projects have clear requirements for core recovery rate. Hard rock strata require a recovery rate above 95%, while fractured and complex strata must reach more than 90% to pass project acceptance.

3. Key Factors Affecting Core Recovery

Complex Stratum Conditions: Fractured rock, broken ore veins, soft and loose interlayers, and strongly weathered strata are the main causes of core loss and incomplete sampling, which are common challenges in gold and nickel mine exploration.

Unmatched Drilling Parameters: Excessive drilling pressure, unreasonable rotating speed and unstable feed speed will crush intact rock cores, resulting in core fragmentation and low recovery rate.

Unreasonable Flushing Fluid Formula: Excessive flushing fluid flow or inappropriate fluid ratio will erode soft rock and broken core, while insufficient fluid supply will cause hole wall collapse and core jamming.

Non-standard Operation & Aging Tools: Improper overshot retrieval operation, worn diamond bits and deformed NQ/HQ drill rods will cause core slipping, blocking and loss during drilling and coring.

4. How to Improve Core Recovery Rate in Field Drilling?

Optimize Drilling Parameters According to Strata: Reduce feed pressure and rotating speed properly when drilling fractured and weak strata, adopt low-speed and stable coring mode to avoid artificial core crushing.

Adopt Customized Flushing Fluid Proportion: Deploy targeted flushing fluid formula for broken and loose strata to strengthen hole wall protection, stabilize downhole environment and prevent core erosion and collapse.

Regular Replacement of Standard Drilling Tools: Use high-precision diamond bits and qualified NQ/HQ wireline coring assemblies, replace worn latch springs and inner barrels regularly to ensure stable core holding and retrieving.

Standardized On-Site Operation Management: Standardize overshot lowering, salvaging and core taking procedures, avoid violent operation, and ensure complete core lifting for each drilling section.

5. Xingda Professional Solutions for High Core Recovery

Hubei Xingda full hydraulic core drilling rigs are professionally optimized for high-standard coring requirements. The stepless hydraulic control system realizes precise adjustment of drilling pressure and rotating speed, adapting to intact hard rock, fractured ore veins and soft weathered strata. Matched with standard NQ/HQ wireline coring tools, the equipment stably maintains a high core recovery rate in complex mine strata.

Aiming at the common problem of low core recovery in African and overseas complex mines, Xingda overseas technical team provides one-stop solutions including stratum judgment, parameter optimization, flushing fluid formula debugging and on-site operation training. We help customers effectively solve core loss, fragmentation and hole collapse problems, ensure long-term stable and high-quality coring operation, and make exploration data more accurate and authoritative.