− | The industry standard for many years has been a mechanical orientation technique utilizing a specially designed core barrel and nonmagnetic drill collar with a compass, camera, battery pack, and timer<ref name=pt03r41>Rowley, D. S., Burk, C. A., Manual, T., Kempe, W. F., 1971, Oriented cores: Christensen Diamond Products Paper, 15 p.</ref>. A typical assembly is shown in Figure 1. | + | The industry standard for many years has been a mechanical orientation technique utilizing a specially designed core barrel and nonmagnetic drill collar with a compass, camera, battery pack, and timer.<ref name=pt03r41>Rowley, D. S., Burk, C. A., Manual, T., Kempe, W. F., 1971, Oriented cores: Christensen Diamond Products Paper, 15 p.</ref> A typical assembly is shown in Figure 1. |