JOHANNESBURG (miningweekly.com) – Diamond explorer Tsodilo Resources has completed a pilot hole drill (PHD) programme at its BK16 kimberlite project, in the Orapa kimberlite field, in Botswana.
The purpose of the programme was to drill pilot holes on the sites that have been earmarked for the large diameter drill (LDD) programme.
The positioning of the initial 14 LDD holes is designed to provide grade estimates for the main kimberlite phases, as well as initial grade distribution across the kimberlite.
The hole diameter of the LDD holes will be 24 inches and the 14 planned holes will provide some 2 000 t of kimberlite.
“To correlate the diamond recoveries directly to the geological model and to ensure that the intersection of the LDD holes is increased, it was necessary to probe all LDD sites with NQ size diamond core holes,” Tsodilo said in a statement on Monday.
Core recovery and depth data were recorded as per standard operating procedure. Core recovered from the pilot hole drilling is stored at the company's Letlhakane exploration camp.
The LDD contractor started operations in May. Initial work comprised collaring the 14 LDD holes immediately adjacent to the PHD holes to a depth of 22 m using 30-inch casing.
“It is expected that this programme will be completed in the second week of July, after which the contractor's LDD Elephant rig will be deployed to drill and recover the kimberlite below the Kalahari overburden using 24-inch holes.”