In the field of geology, mainly when targeting gold, the accuracy and precision of drill core analysis are paramount for understanding the geological features and potential mineralisation of an area. As a field technician, two critical tips for marking up drill cores can significantly enhance the quality of the data collected. Both tips emphasise the importance of meticulous attention to detail and adherence to established protocols to support the successful exploration and evaluation of gold prospects.
Tip #1
Firstly, ensuring an accurate orientation of the drill core is essential for taking structural measurements that can reveal vital information about the geological formations encountered. This process involves using an orientation rack and following specific steps to mark the core accurately.
- Ensure an accurate orientation.
- Your drill core may need to be orientated if required for taking structural measurements.
- Using an orientation rack, ensure three runs of the core are lined up in the bar and the driller’s ori marks line up; you can then draw a solid red line in between.
- This line can now be extended until there is a significant break in the core or the driller’s ori marks start to not line up.
- A dashed line can be drawn if the ori confidence is lower.
Tip #2
Secondly, ensuring accurate metre marks on the drill core is crucial for maintaining a precise record of the drilling depth and the corresponding geological observations. This step requires careful measurement and consultation with senior geologists and drillers, especially in cases of variance or core loss.
- Ensure accurate metre marks.
- Once the drill core has been orientated, you can then metre mark the core.
- Start at the hole’s beginning, measure each metre, and mark on the drill core, using the driller’s core blocks as a guide.
- If the variance between the driller’s core blocks and your metre marks goes over 20-30cm, consult your Senior Geologist and driller. Never move or remove the driller’s core blocks without consulting.
- For breaks in the core – ensure you measure from the short point to the long point of the core to ensure an accurate measurement.
- For core loss – the drillers will write on the core blocks how much is missing, and this will need to be added to your measurements.
- For broken core, you may need to rely on the driller’s core blocks while measuring, as it is too hard to measure the broken rock itself.
