March/April 2012

Drill and blast

Compiled by Eavan Moore

A better button bit

A new drill bit design from Rockmore International promises to boost productivity. The B6 button bit has six tungsten carbide inserts on the periphery row; their diameters are about one millimetre larger than previous models, effectively lengthening bit life. Additional changes in flushing design include flutes strategically placed between the button inserts to carry water and rock cuttings away from the bit face more efficiently, thus increasing penetration rates. “The previous B3 design was very much industry standard for all manufacturers of this class of bit,” says Pejman Eghdami, Rockmore’s executive vice-president. He says the new design, therefore, represents an industry-wide improvement. It comes in a 45-millimetre head diameter and is compatible with any R32 thread drill rod connection.

 

 

Customized compressors make sourcing simple

National Compressed Air specializes in customized high-pressure compressors. The powerful rotary screw compressors are available in single- and double-stage models, with a choice of engine types and mounts. NCA compressors use a fuel-saving combination of engine speed and air intake modulation. They can be tailored to customer requirements without much cost increase, says sales and marketing manager Pran Kirtani, and their volume and pressure specs are an industry standout. “If someone is looking for 200 PSI or higher in a single stage, it will be hard to find, whereas we can easily provide that product,” he says. “Our double-stage compressors can go up to 1,700 CFM in volume and 500 PSI in pressure, which is, perhaps, the highest in the industry.”


Water at work


The Wassara water-powered drilling system creates deeper, straighter holes than systems using compressed air. As water returns upward through the drill hole, it flows at much lower volume and velocity. This reduces damage to the casing and allows a smaller gap between the hammer and hole wall, making a typical drill deviation only 0.5 to 1.5 per cent. Water-powered in-the-hole (ITH) drills consume about 80 per cent less energy and contribute to a working environment free of dust and oil mist. Purpose-built rigs are available from Atlas Copco, Sandvik and Cubex, but Wassara also sells individual components to retrofit existing rigs. “In essence, all drill rigs can be adapted to Wassara,” says Pål Jensen, business area manager for mining at Wassara.

 

 

Easy, electronic detonation

Accurate and individually programmable, electronic initiation systems offer a safe, flexible and reliable alternative to pyrotechnic detonators. DynoNobel’s SmartShot system boasts robust water-resistant connectors, quick training and ease of use, and a 20-second detonator delay. “We offer the longest delay on the market,” says Campbell Robertson, conversion manager, electronic detonators at Dyno Nobel. “It allows some mines to shoot larger shots.” The system includes up to 250 electronic detonators on one string starter; a bench box that receives radio frequency, leaky feeder or wired signals; and a base station used to initiate the blast from a safe distance. A handheld tagger tests and assigns timing to detonators. Different versions are sold for underground and surface operations.


When the going gets tough...

Pacific Blasting and Demolition provides audit services and drill and blast work in North America and abroad. The company specializes in wall control, but mining manager Ron Woolf says it is multi-faceted and welcomes challenges: “As a specialty contractor, we’re able to go in and do almost everything for a client. We’ve proven that we can go into an area that has experienced a lot of difficulties in the past and come out with favourable results. We have a vast talent pool of some really good guys.” The company has handled access road construction in difficult terrain, portal development, rock slope stabilization and tunnel rehabilitation. Its capabilities include complete mine contracting services, and production drilling and blasting.

 

Track-Mounted versatility

This track-mounted in-the-hole (ITH) drill forms part of Cubex’s underground Constellation series. It can produce drill holes up to 330 feet deep and 3.5 to eight inches in diameter without additional tools. With a 12-inch hammer, it can ream up to 17.5-inch diameter holes. The automated Accra Feed system provides optimal pressure to the bit, while the ERIS control panel allows real-time monitoring from an expandable four-legged platform. “We’ve designed it to be a heavy duty, lower maintenance and extremely versatile underground ITH drill,” says Cubex marketing manager Kerry Falk. “It can switch from 30-inch blind boring with a Machines Roger V30 to production drilling with a six- or eight-inch hammer.”

 

 

The power to dominate

Operating at air pressures of 100 to 435 PSI, the Halco Super Dominator 500 hammer is built for power. It has no liner, leaving space for a bigger, harder-hitting piston. A one-piece top adapter with no-return-valve makes inspection and service simple, and an integral finger eliminates shimming. “Halco has maintained a simple design in its hammers for ease of service without compromising performance,” says sales support engineer Chad LaRoche. “The Super Dominator line has achieved great results in blast hole applications, both in surface and underground mining.” Halco hammers come with API pin adapters but have been fitted with other thread types by customer request. Drilling diameters range from five to 6.5 inches.

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