DRILLING METHODS Sample Clauses
DRILLING METHODS. Atna’s program utilized both reverse circulation (RC) and diamond core drilling (DDH) methods. Reverse circulation drilling was used primarily as pre-collars for diamond core tails. This was done to minimize costs in the barren material above the mineralized fault zones. Diamond drilling was utilized to provide better confidence in sample quality than can be expected from RC drilling methods, as well as to provide for rock quality calculations and better geologic definition of the structurally controlled ore zones for engineering and modeling purposes. The distribution of reverse circulation versus core holes is discussed in Section 17.3 of this report. Table 11-2: Summary of Atna Resources Phase I Drilling
DRILLING METHODS. All borings shall be drilled by a method of the Contractor’s choosing unless otherwise specified under the Site Specific Section of the Scope of Service. The method(s) shall be proposed by the Contractor and approved by the COR prior to use. The method(s) shall be discussed in the Contractor work plans. The drilling method must allow, or provisions must be made for, accurate determination of the depth to ground-water surface. If a well is to be installed in a boring, the boring shall be of sufficient diameter to permit at least two inches of annular space between the boring wall and the sides of the centered riser and screen. The boring diameter shall be of sufficient size to allow for the accurate placement of the screen, riser, centralizers, filter pack, bentonite, and grout. The Contractor’s drilling method shall maintain the integrity of the borehole (i.e. prevent collapse) during backfilling or well installation. No grease shall be used on drill pipe joints. The use of any lubricants shall be submitted for approval in the Contractor work plans and shall be noted on the boring logs. The Contractor shall provide documentation (brand name, chemical analysis of product composition, SDS, etc.) to the COR for all materials introduced into the boring during drilling, for approval prior to use.
DRILLING METHODS. Any exploration well which the Contractor becomes obligated to drill under this paragraph 1 of Article VI shall be drilled in accordance with generally accepted methods used in the international CBM industry and shall be deemed drilled upon the first to occur of the following:
a) it reaches the projected depth;
b) it becomes a Discovery Well;
c) it reaches basement rock; or
d) it encounters impenetrable substance or excessive geothermal gradients.