Modern Mining April 2018

PRODUCT News

Using diamond-impregnated bits and a standard rotary percussion rig, deep drill- ing experts Torque Africa Exploration recently drilled their way into the record books with a hole drilled in the Springs area reaching 1 148 m. This is reportedly an African record and one of the deepest rotary percussion holes drilled worldwide in mixed and largely Torque Africa sets a new African drilling record unchartered geologies and the contract calls for yet more and deeper holes in future. Nardus Bezuidenhout, Director, Torque Africa, explains that the company is part-way through its contract to bore several deep-level holes into disused mine stopes for the treatment of acid water mine drainage.

pivotal and that Sandvik bits and hammers were going to be key to getting the job done efficiently. “Considering the unchar- tered nature of the geology of the area, we chose to use standard bits and then switch to diamond-impregnated bits as soon as formations became too hard or abrasive for them.” “This is exactly what we encountered after the initial depth of about 300 metres of dolomite and shale and from there on it was mostly hard quartzite with some khaki shale, black slate shale, mixed dolomite and quartzite, diabase and more quartz- ite. This made for some tough drilling but was made considerably easier with the use of the diamond-impregnated bits,” says Bezuidenhout. He explains that considering the forces at these depths only the highest quality bits could be used and even despite the higher cost of diamond-impregnated bits, the durability was extended beyond 378 m per bit. This far outweighed the standard bit alternative which would have been 70 m and required constant pullouts. Bit changes can be complicated and time-consuming as pull back of the rods would take up to 24 hours to retrieve the 6-m lengths to replace the tooling. A shanked bit at these depths would be even more catastrophic and could require drill- ing of a new hole if the bit could not be retrieved. “We had to deal with dolomite wet- lands, dykes, voids and water ingress at all levels which made it tough,”Bezuidenhout continues. “We were also required to drill the hole telescopically from its original diameter of 558,9 mm at the top through various layers including a 310-m deep grouted section, casing and eventual inter- section of quartzite just beyond 300 m at which point the drill diameter was down to a 172 mm bit. “Thereafter we continued through vari- ous phases until prematurely intersecting the stope at 1 148 m instead of the pre- dicted depth of 1 200 m. At this point the bit size was 124 mm and the hole ready to be used by our clients to receive pumped products that are a by-product of the treatment of millions of litres of acid-mine drainage.”

Faggiolati pump is engineered to operate in extremely harsh environments including handling highly corrosive water and slud- ges. These high-performance pumps are able to withstand acidic water even when it contains high concentrations of metals and sulphates as well as slurries contain- ing abrasive particles and a high content of solids. “Dewatering, whether on surface or underground, requires absolute reliability and this has become the watchword for our pump rental fleet; all pump brands have been selected for their performance capa- bilities as well as their robust construction,” Vine says. I ntegrated Pump Rental has an established reputation for providing fit- for-purpose dewatering solutions to its customer base, and the company operates an extensive fleet of pumps that caters for all types of application requirements. The company offers a total round-the-clock pumping solution, and takes complete responsibility for all maintenance of pumps on site. Integrated Pump Rental, tel (+27 72) 627-6350, website: www.pumprental.co.za These range from a few hundredmetres below the surface to over 1 200 m for the deepest hole and require all the ingenuity of the company’s technical experts, as well the expertise of Bezuidenhout himself. According to Bezuidenhout, Torque Africa took on the job in the face of other experts who said the risks of failure were too high. “We were never in doubt though and, in conjunctionwith Pieter Coetzee and his team from Sandvik Mining and Rock Technology’s rock tools division, planned the technical details of the operation.” Sandvik’s Product Manager – DTH Bits, Matthew Shoffner, also worked with the local team of experts to find the right technical solutions and it soon became apparent that the right tooling would be

Torque Africa Exploration has drilled a record- breaking rotary percussion drill hole on a contract in the Springs area.

Stainless steel pumps added to rental fleet Integrated Pump Rental recently bolstered its pump rental fleet with the inclusion of a range of stainless steel submersible pumps. Managing Director Lee Vine says this was done to specifically cater for applications where there are increased levels of acidity in the water.

“Acid water drainage on mines is com- mon today, and these extremely harsh dewatering applications require an appro- priate pumping solution which is why we have added Faggiolati stainless steel slurry pumps to our rental fleet,”Vine says. Constructed from 316 stainless steel, the

Integrated Pump Rental now has available a range of stainless steel submersible pumps.

Sandvik Mining, tel (+27 11) 929-5300, website: www.rocktechnology.sandvik

50  MODERN MINING  April 2018