Sandvik Mining and Con-struction is offering a new 60-mm tool system for drilling quarry holes up to 152 mm in diameter with hydraulic tophammers. The company reports that quarry managers in France and Germany are already using them as an alternative to DTH hammers. Sandvik reports that the new system is capable of drilling straight, clean blastholes up to 25 meters deep nearly twice as fast as DTH hammers and using half the fuel. It also offers greater flexibility in hole size in the 90 to 152 mm range. Since it also uses lighter, more agile and more easily transportable drill rigs, it is highly suitable for drill-and-blast contractors.
On the DTH side, there are also new tool-led solutions that promise to bring down costs. For example, an advanced new grade of cemented-carbide has just been introduced for DTH bits. Tackling the widest range of rocks ever in an optimal manner, this new “silver bullet” only requires that the user chooses the best button-shape and bit-face design for the rock formation in question.
In terms of dimensional stone mining, where precision is critical, the rock tools are even stronger determiners. Sandvik reports that in slate quarries in Spain, a new guide-bit fitted with cemented-carbide buttons instead of chisel-type inserts is meeting very high demands. Most crucially, it is maintaining straight holes in horizontal applications up to 25 meters long. Elsewhere, in much harder and more valuable stones, such as granite, the new button bit offers straight drilling with fewer re-grindings and optimal service life.