Explorational Surface Diamond Drilling
posted on
Feb 05, 2014 02:54PM
Black Horse deposit has an Inferred Resource Now 85.9 Million Tonnes @ 34.5%
Exploration diamond drilling differs from other geological drilling in that a solid core is extracted from depth, for examination on the surface. The key technology of the diamond drill is the actual diamond bit itself. It is composed of industrial diamonds set into a soft metallic matrix.
The diamonds are scattered throughout the matrix, and the action relies on the matrix to slowly wear during the drilling, so as to expose more diamonds. A rotary drill uses a diamond encrusted drill bit to drill through the rock. The bit is mounted onto a drill stem. An actual diamond bit is a complex affair, usually designed for a specific rock type, with many channels for washing.
Water is injected into the drill pipe, so as to wash out the rock cuttings produced by the bit and also to reduce the heat produced due to friction which causes less wear and tear of the bits.
The drill produces a "core" which is photographed and split longitudinally. Half of the split core is assayed while the other half is permanently stored for future use and re-assaying if necessary. Although a larger diameter core is the most preferred it is the most expensive. The most common diameter sizes of core are NQ and CHD 76.
Before the current 2014 KWG & Bold Koper Lake drilling campaign, 49 BQ and NQ-sized holes totalling 7,469 metres have been drilled on the property, not all of which have tested the chromite zone.
While some of following individual techniques might not be used in the 2014 Koper Lake drill campaign, here are three videos to better visualize the process of surface diamond drilling and how the pieces of drilling equipment used are fit together.
Orbit Garant Drilling uses Devico's DeviDrillâ„¢ directional core barrel technology on several projects however it is unclear as to whether KWG has requested it's use, which would have replaced the need for "wedging", (which improves core drill angles), a technique recommended by Sibley Basin in KWG's Koper Lake NI 43-101, September 7, 2013 Technical Report.
Previous Ring of Fire Drill Campaign Rigs
Example core from Big Daddy