Diamond Core Drilling Clause Samples

Diamond Core Drilling. The diamond core program conducted by Atna was completed by two contractors, R▇▇▇ Drilling of C▇▇▇▇ Fork, Idaho and L▇▇▇▇ ▇▇▇▇▇▇▇▇▇▇▇ of Chandler, Arizona. R▇▇▇ used an LF-1500 truck-mounted drill capable of depths up to 1500 feet with HQ rods, and 2000 feet with NQ. The rig was suitable for the shallower core tails, up to about 1400'. For deeper holes (up to 1800') it was necessary to resort to a L▇▇▇▇▇▇▇ 3000 truck-mounted rig, capable of drilling to 3000’ with HQ rods. This rig was provided by L▇▇▇▇ ▇▇▇▇▇▇▇▇▇▇▇. Both contractors staffed their rigs with a minimum of two (driller and helper), and added a water-truck driver for deeper holes. Coring was completed using HQ triple and dual tube extraction methods. In triple-tube extraction, the rock is cut using a diamond-impregnated bit. The cut rock is fed through the center of the bit as drilling deepens and is stored inside a split tube contained in an outer core tube. After a run is completed, a wireline is dropped down the hole to pull the combined assembly. The triple tube is then extracted from the outer core tube by using hydraulic pressure to force the triple-tube from the outer tube. Core is recovered from this tube by opening the internal split tube and placing the core into the core boxes for transport, logging, and storage. This method ensures a greater degree of rock integrity, allowing for better lithologic, structural, and rock quality designation (RQD) descriptions of the rock. Standard dual- tube extraction of core follows the same procedure, except that the core retrieval is accomplished using just the outer tube of the above configuration, and is extracted by direct pumping of the cylinder of drill core itself, or by pounding the rock out of the tube. In highly fractured zones this often leads to degradation of intact core.