ROCK TOOLS
While in some parts of the mining industry basic designs can remain unchanged for decades , in drill bits there has been something of a flurry of innovations over the last year , often involving quite fundamental ‘ outside the box ’ thinking and changes . A good example is from Boart Longyear , a leading provider of drilling equipment and performance tooling , which recently announced the launch of a new IMPAKT™ line of drill bits .
The rock tools team at Boart Longyear used advanced computational modelling to identify a deadpool at the centre of traditional bit designs . This deadpool it says results in significant wasted energy due to inefficient flushing . In more detail , standard designs focus on clearing the gauge . Opposing pressure causes stagnation of cuttings on the face . This deadpool creates a cushion against effective energy transfer .
The solution Boart Longyear argues is its IMPAKT top hammer bit , featuring a patent pending ‘ Raceway ’ face profile . “ Immediately recognisable as unique , the new IMPAKT bit eliminates the deadpool , improving drill string energy transfer and overall drilling performance .” The Raceway design clears both the face and the gauge . Increased pressure and flow accelerate cutting removal , with all buttons in contact with fresh rock maximising efficiency in each strike . After development and global third party testing , this design innovation it says has been proven to actively clear cuttings from the entire cutting face . With flushing speeds increased by 25 %, the resulting penetration rate has been improved by an average of 18 %. “ We were fortunate to work with a major third party
Boart Longyear ' s IMPAKT top hammer bit features a patent pending ‘ Raceway ’ face profile
On the face of it
Rock tools are by no means standing still , with innovations in development all the time to help maximise productivity , efficiency and sustainability , reports Paul Moore customer during development and testing ,” says Jeff Hogan , Global Product Line Manager for Rock Tools at Boart Longyear . “ Real world trials using a range of OEM drifters demonstrated alignment with our developmental testing and validated our innovation to deliver value for our customers .”
The IMPAKT line of tools will launch with a concise range of bits designed specifically for underground long hole drilling . These bits are available with hemispherical or parabolic carbides in sizes ranging from 64 mm to 89 mm . In summary , the IMPAKT face design is based on reducing the residence time of cuttings at the face . Raceway flushing quickly clears cuttings from the entire bit face for a lower Cuttings Residence Time ( CRT ) and more effective energy utilisation .
Padley & Venables takes XDC further
Following on from the successful launch of its
Padley & Venables XDC range has been expanded to include drill bits for bolting and boring , with diameters ranging from 45 mm up to 115 mm
Extreme Drop Centre ( XDC ) button bits for underground production drilling in 2022 , the range from the UK ’ s Padley & Venables has been expanded to include drill bits for bolting and boring , with diameters ranging from 45 mm up to 115 mm . Geometry-wise , XDC bits have larger tips for greater wear resistance , plus larger face flushing holes with deeper and wider grooves . There is a deeper drop centre and a face tip groove to increase secondary flushing as well as an optimally positioned side flushing hole .
Using state of the art simulation software alongside extensive field testing the XDC range has been designed to break rock faster and reduce hole deviation . The initial reduction in hole deviation by 25 % has been reinforced by further testing across both development and production drilling . The company told IM that the effect of hole deviation cannot be understated as it negatively impacts every element of mine management . It adds : “ Being manufactured in Britain from European steel is not the only reason Padley & Venables ' drill bits are the driller ' s choice . It ' s also over 100 years of history and experience alongside continual product development that has made our drill bits the quality they are today .”
LKAB Wassara ’ s three in one
LKAB Wassara ’ s water powered DTH drilling it sees as being an environmentally friendly and energy efficient alternative in underground mining . Water power makes it says makes it the ideal choice for drilling in sensitive areas as well as for drilling long straight holes . The waterpowered hammer is capable of penetrating almost any formation while maintaining speed and accuracy .
It consumes less than 25 % of the energy of equivalent air-powered drilling methods . Also , air-powered DTH Hammers need about 800 litres of lubrication oil during their lifetime . Wassara ’ s water-powered DTH Hammers requires 0 litres . The water both powers and lubricates its hammers at the same time . The technology is widely used in mining , including its parent company LKAB ’ s Kiruna and Malmberget underground iron ore operations .
This year , Wassara introduced the W120 . G3- hammer , a water-powered hammer that has three functions in one : rock drilling , casing advancing and jet-grouting . W120 . G3 is the new and improved 5 in hammer from Wassara . It is more powerful and is designed to provide a higher ROP compared to the standard W120 due to a heavier piston , especially in softer formations . Together with the integrated check valve this makes for a very good hammer .
It is also useful to discuss water hammer technology in relation to specific mining methods . In block caving for example , when
20 International Mining | NOVEMBER / DECEMBER 2023