Boart Longyear’s Drilling Services Division (CDD) at work at Anglo Gold’s Kopanang Mine - Vaal River Operations.

Situation:

Urgent need to drill a 1200m Long Incline Borehole (LIB) at Anglogold’s Kopanang Mine.

Challenges:

Tight time limits
Just six months to complete
Restrictions on operating time and productivity
6,5km walk between shaft to drill site taking an hour each way. Reducing
productive operating time for the four man drill crew to six hours per shift.

Solution:

Given the time constraints attached to this project, it was imperative that the exploration drill team was equipped both with exteansive LIB experience and proven technology. With a fleet of eight hydraulic LM75 exploration drill rigs fitted with BRQ rods in service in gold and coal mines across South Africa - each with a proven capability to drill 1200m BX size holes - the contract was awarded to Boart Longyear’s specialist exploration Drilling Services Division.

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Method:

The hole was planned to start at an inclination of –40 degrees and to finish at around +30 degrees.

Controlled drilling was conducted up to 60 metres. A survey indicated that an inclination of –39 degrees had been sustained.

Further surveys were conducted at 50m intervals and the first directional retractable wedge was installed to increase the inclination at 642 metres. Three more retractable wedges were installed to increase the inclination to +15:872 degrees: a total deflection of 24 degrees in 230 metres. Thereafter five non-directional wedges were installed to complete reef intersections for sampling purposes.

Result:

Completion of the 1 034m hole was achieved - including surveying and wedging - in just 80 working days. “The job went extremely well,” commented Kopenang geologist Terry Adam. Completing a hole to this depth is usually expected to take between 10 and 12 months. Boart Longyear CDD overcame this by using ”an extremely effective, novel method of lifting the hole to a curvature of 1 degree in every 10 metres drilled.”

BRQ Deep Drilling Reverse Thread Rods

New BRQ high performance wireline drill rods developed by Boart Longyear in Canada give longer rod life with less hassle, says Boart Longyear exploration manager Malcolm Smith.

Featuring a unique, patented joint design that expands drilling capabilities, the BRQ reduces down time due to rod failures and lowers total drill rod cost per metre in even the most rugged conditions.

“The high performance BRQ box thread ‘hooks’ itself into the pin thread due to the reverse flank on the thread design,” explains Smith, “ and the benefits include extended rod life through the virtual elimination of belling and bulging, reduced in-hole failures and far superior depth capacities.”

One of the first South African mines to be introduced to the rods has been so impressed by their performance that it has decided to use them as standard.