Spotlight Feature Articles Hexagon Explosives & Blasting Aug 16 | Page 8

EXPLOSIVES AND BLASTING
excavators – alongside benefits like improved mineral liberation , maximised digging rates , and increased bucket payload .
BME says it has also been a pioneer in the field of electronic detonation , developing the AXXIS digital initiation system – which has become an industry standard and which was recently released in an updated GII version . Using the AXXIS system , electronic detonators can be programmed for ignition within milliseconds of each other , to suit operator needs and the particular geology of the rock .
“ This level of timing accuracy allows for optimal interaction of the shock-waves between adjacent blastholes , so that fragmentation is enhanced ,” said Rorke . “ For instance , crusher throughput and power consumption are strongly influenced by blast fragmentation distribution .”
He said a reduction in coarser fragmentation increases crusher throughput and an increase in finer fragmentation results in more material bypassing the primary and secondary crushing circuits , with less energy being consumed in the crushing process .
“ Similarly , feed size distribution has a significant effect on autogenous and semiautogenous mills ,” he said . “ The grinding mechanism in autogenous mills is one where larger fragments are ground down whilst smaller fragments are crushed by the larger ones . If the mill-feed contains too few coarser particles , the mill efficiency and throughput drops rapidly .”
Research also shows that additional macroand micro-fracturing within individual fragments from the blasting makes fragments easier to fracture further , using less energy in the crushing and grinding phase .
Enhancing the versatility of electronic detonation has been BME ’ s range of software and hardware advances , says the group . “ While the AXXIS system has improved safety , ease of use , robustness and accuracy of blast timing , the company also developed the BlastMap computer software program – now in its third generation of improvement .”
“ Used together with AXXIS , BlastMap III gives customers optimal blast results and makes blasting much more efficient ,” said Rorke . “ It allows the fine-tuning of blast parameters that include vibration control , fragmentation optimisation , dilution control , heave control , and specialised blasting scenarios .”
Underground remote detonation
Becker Varis says it “ has always been committed to providing the best communication , automation and service in the industry ” and since 1996 its smartcom ® leaky feeder system has gained it a very positive international reputation in underground mining . It is also the backbone for many system add-ons including the smartblast ® product line . Working in conjunction with the
The latest addition to the smartblast products , the 1673 series , has the capability of programming up to 64 remotes to one single controller
leaky feeder system , smartblast provides full two-way blast control for underground and surface applications .
The company states : “ The first smartblast system was commissioned a decade ago and Becker Varis hasn ’ t looked back having installed numerous systems worldwide and counting . It all started with the rugged 1670 series smartblast which provides a simple to use remote detonation package of up to eight remotes per controller . And the 1670 did not disappoint as customers have calculated return on investment within six months on reduced maintenance costs alone as it eliminates the need to maintain a separate central blast cable system , not to mention the numerous safety benefits .”
The latest addition to the smartblast products , the 1673 series , has the capability of programming up to 64 remotes to one single controller which eliminates the need for multiple controllers when more than eight remotes are required . The 1673 series also has many added features such as a history event log with backlit LCD display , post blast confirmation , sequential firing and increased firing capacity . “ The history event log keeps a record of information such as unit state , post blast motion detect value , firing voltage level , battery level and the date and time the event was logged . Each remote is equipped with a sensor that measures the seismic motion that may be expected when a successful blast detonation has occurred and reports this information back to the controller which can be useful in underground applications when a blast cannot be easily detected .”
Hexagon HxGN continues to enhance blast planning
HxGN Blast optimises the design and execution of drill and blast plans from within the MineSight 3D mining environment and Hexagon Mining says that the software module has continued to receive significant enhancements such as fragmentation analysis tools ,
electronic detonator design tools , conditional design and charging templates , importing and exporting options , bootleg validation , surface generation , and a stand-alone version . The company states : “ With an estimated 2-3 % of the world ’ s total energy required for comminution , the need to optimise fragmentation and associated costs while maintaining a safe working environment should not be underestimated .”
HxGN Blast allows simple configuration of consumables that are used on site within its Blast consumable library . The consumable library is configurable to suit any chosen equipment supplier , which takes into account the large range of providers and different equipment options .
Estimated cumulative particle size is displayed as a curve detailing the size distribution . Blasting and design parameters can be adjusted to optimise the fragmentation , which potentially improves all downstream processes , including energy consumption , maintenance costs , safety , and efficiency at the mine .
The ability to assign multiple decks is another new feature within HxGN Blast . This is particularly useful when a coal seam or weakness seams are being blasted . Decks are set up in the Blast Project configuration area and are consequently assigned in the charging template . Timing options are also available for each
HxGN can display several strings or channels connecting the blast design
International Mining | AUGUST 2016