In a single year, MAXAM drills about a million metres of blast holes in Poland. It has had as many as 20 Epiroc drill rigs distributed across Poland, providing services to quarries producing granite, dolomite, sandstone, basalt, and melaphyre aggregate, as well as limestone for cement production and other components for construction chemicals manufacture.
In Poland, quarry walls may have a thickness of 12 to 28 metres. Popular hole diameters are 89mm, 95mm and 102mm. In purchasing new rigs, MAXAM was committed to reducing total operating costs. It proceeded to trial a T40 rig at a granite quarry in Rogoznica, in the southwest.
The trial comprised two grids of holes spanning 2000m, allowing for a reliable assessment of the drilling costs and the actual tool wear. Until the trial, most blast holes in Poland were designed without consideration of the wall profile or verification of completed hole quality directly after drilling.
The use of HNS helped to maintain the depth level of all drilled holes and to avoid uncontrolled excess drilling. The drilling parameters sampled with the MWD system enabled the estimation of quality and possible adjustments (via generation of a table of drilled hole bottom deviations in relation to the planned position) immediately after completion of the grid. In addition, the SmartROC technology indicated that holes could be drilled at nearly half the cost.
The results exceeded the MAXAM personnel’s expectations. During the trial, the T40's average drilling progress was 1.1 metres per minute (m/min), compared to 0.8m/min on a ROC F9C. The T40’s fuel consumption was 0.5 litres per metre (lpm) of hole; the ROC F9C varied from 0.9 to 1.1 lpm.
The results of the trial convinced MAXAM that the T40 was a worthwhile purchase and there was significant promise of a return on investment in time and fuel savings. The Epiroc technology has further modernised MAXAM’s drill and blast works and presented opportunities for more precise projects with greater quality. It has also reduced total costs by more than 30 per cent (through reduction of the consumption of fuel and explosives, the lack of additional edges and the drop of seismic vibrations during blasting).