Sandvik Mining says Alpha 330 delivers 30% to 80% longer rod life than the R32 system, as well as exact collaring and straighter holes – delivering reductions in drifting and tunnelling costs.

The Alpha 330 drilling tool system has been developed to match the increased energy output from modern high-power rock drills in drifting and tunnelling applications, product support manager for tophole and DTH drills Des Leonard said.

“The Sandvik Alpha 330 drilling tool system has been designed to effectively control drilling power and, most importantly, ensure that it is transmitted into the rock as efficiently, accurately and economically as possible,” he said.

The drill string rod and bit connection features an entirely new thread design.

“A shorter thread on the hexagonal rods in the tool system results in a rigid, integrated power pack drill string with superior resistance to bending stresses, securing perfect energy transfer,” Leonard said.

“This sturdy thread design is well guided inside the bit skirt, offering higher precision in collaring – even in complex rock formations and uneven surfaces.

“More steel for higher fatigue strength ensures a significantly more rigid connection compared with the R32, resulting in exact collaring and straighter blastholes – and delivering a 30-80% increase in rod life.

“The result is in higher rates of advancement, improved profile-control and a further reduction in the overall cost of drifting and tunnelling through Sandvik Mining technology.”

According to Leonard, the Alpha 330 system takes advantage of an inherently stronger and more rigid R33 thread with a significantly larger cross-section than the R32, making it proportionately stronger.

“To further improve rigidity, Sandvik has introduced a new guiding function between the rod and bit-skirt, immediately behind the thread,” he said.

“The Alpha 330 rod cross section over the guide is 36% larger than on the R32 at the rear of the connection, greatly improving the rigidity of the joint,” he said.

“After the bit skirt, the rod cross-section increases to Hex-35 quickly and smoothly.

“The sturdy thread is well guided inside the bit skirt, offering high precision in collaring – even in complex rock formations and uneven surfaces.”