is a method to retrieve cores samples from the ground. Coring is often utilised in ocean drilling and surveying. Scientist often using coring to acquire core samples
Coring is used to aerate
a golf course. A special coring machine removes cores from the green which helps the roots obtain air and moisture. Coring also alleviates compaction in high traffic areas.
Drilling equipment is often used for coring. Rock core is often taken during mineral exploration operations to help determine the rock type and amount of mineralisation present. A diamond impregnated core bit is used which is rotated to cut an annulus of rock, producing a rock core which extends through the bit into the core barrel. In a wireline system, the core barrel can be retrieved using a wire cable that is run inside the drill rods. Thus, the drill rods do not have to be removed from the borehole each time a core run is complete. Diamond coring can be carried out to depth of 2000m using conventional mineral exploration drilling equipment. Core can be recovered from deeper wells but the operation becomes more expensive.
Coring happens when a heated alloy, such as a Cu-Ni system, cools in non-equilibrium conditions. This causes the exterior of the material to harden faster than the interior. Coring causes the exterior layers to retain more of the higher melting temperature element. In this case, the dendrite
arms formed from the exterior have a different composition than the alloy in the inner regions, resulting in a local compositional difference.
- Beddoes, J. and Bibby, M.J. Principles of Metal Manufacturing Processes. Elsevier Butterworth-Heinemann, 1999. ISBN 0-340-73162-1
"Materials Science and Engineering An introduction" by William D. Callilster Jr.