This document discusses core orientation techniques for measuring structures in oriented drill core samples. It provides examples of qualitative examination needed to identify key structures before measurement. Details are given on recording gravitational roll or magnetic tool face readings for inclined or vertical drill holes. The process of aligning an orientation block, attaching it to the core, and using a survey camera to obtain orientation readings is described. Methods are outlined for drawing a reference line on the core and measuring alpha and beta angles to structures relative to this line. Finally, examples are given of logging formats and explanatory notes for recording discontinuity data from oriented drill core.

1. Core Orientation on DrilledCore Orientation on Drilled
CoresCores
Some Examples and Experiences onSome Examples and Experiences on
JurongJurong Formation, SINGAPOREFormation, SINGAPORE
Dr. KYI KHIN
Monthly Seminar
(Underground Engineering Technology Division)
29 April, 2011

2. How to measure structure inHow to measure structure inHow to measure structure inHow to measure structure in
Oriented CoreOriented CoreOriented CoreOriented Core
Before you measure
Need Qualitative Examination
What structures are present?
Kyi Khin (April, 2011)
What structures are present?
What rock elements define that structures, lithologies,
alteration and veining?
What sectors of the core have constant attitudes of
structures and what sectors show variability?
Is the Joint/Cleavage steeper than the Bedding?
Is the asymmetry Sinistral or Dextral?
Is the drill hole Incline or Vertical?

3. Geologist needs to know..
• Which structures need to be measured?
• Which context need to be established in
Logging Format?
Kyi Khin (April, 2011)
Logging Format?
• How many and which parts of the core
measurements need to be taken?

4. What to Record?
Incline Hole
• Gravitational Roll Reading (GVR)
Kyi Khin (April, 2011)
Vertical Hole
• Magnetic Tool Face Reading (MTF)

6. Vertical Core Orientator Components
Kyi Khin (April, 2011)

7. ALIGN Ori-Block with SURVEY CAMERA
Kyi Khin (April, 2011)

8. ATTACH Ori-Block
Kyi Khin (April, 2011)

9. SCREW BACK Ori-Block
Kyi Khin (April, 2011)

10. TAG BOTTOM of the CORE
Kyi Khin (April, 2011)

11. SURVEY CAMERA READINGS
Gravity Roll Angle-GVR (for Incline Hole)
Magnetic Tool Face-MTF (for Veritcal Hole)
Kyi Khin (April, 2011)

12. Kyi Khin (April, 2011)

13. Ori-Angle Recording
Kyi Khin (April, 2011)

14. Draw the Reference Line (MN)
Kyi Khin (April, 2011)

15. Measuring the Alpha (α) and Beta (β)
angles
Kyi Khin (April, 2011)

16. Measuring the Alpha (α) and Beta (β)
angles
Kyi Khin (April, 2011)

17. Relationship of Alpha, Beta, Gamma to
Reference Line
Kyi Khin (April, 2011)

18. Ezy Logger Tool
Kyi Khin (April, 2011)

19. Logging Format
Kyi Khin (April, 2011)

20. EXPLANATORY NOTES FOR DISCONTINUITY LOG
(Based on BS 5930, 1999)
Prepared by Kyi Khin (2010)
Kyi Khin (April, 2011)

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