J&S Drilling recently completed a geotechnical drilling campaign at a Coal Mine in the Bowen Basin. The scope of works called for a series of boreholes. Bore depths up to 30m using various drilling technique for potential future infrastructure projects.
Our Fraste XL Max drill rig completed the project in a safe and efficient manner. Our drilling suite and crew selected for the project quickly built a professional reputation. Based on safe production, presentation and successful delivery of various projects across various mine sites. Furthermore on time and on budget project completions.
We drilled the bore holes using a hollow-stem auger methodology. From the surface through the tertiary sediments until low strength rock encountered. During the advancement of augers, we collected Standard Penetration Test (SPT) and U-63 push tubes samples. Taken at intervals requested by the supervising geotechnical engineer.
Once refusal established through the process of SPT sampling (30 SPT blows over 150mm travel = refusal). The Hollow-Stem Augers were extracted from the borehole. Using rotary mud method the temporary HWT steel casing was then flushed to depth. The HWT casing aids in hole stability so HQ3 wireline coring can take place.
HQ3 wireline core methodology is also required. Advancing the borehole from the low strength rock to medium-high strength rock. Diamond surface set and Impregnated diamond core bits are also trialled throughout the project. Establishing the best penetration rates and core recovery. The drill team found that the diamond surface set core bits is more effective. For both core recovery and maximum penetration rates in that area. This information identified through the core recovery sheets. Where the core runs are timed from start to finish and the core recovery is calculated through percentages (%).
Approximately 99% of core recovery achieved across all bore holes. This greatly assisted in allowing the engineering team to subsequently provide their client with an accurate report in a timely manner.
