UNDERGROUND DRILLING
UArizona deploys JH Fletcher drills at SX mine lab
JH Fletcher equipment has been playing a central role in the expansion of the San Xavier mine in Arizona . To give it its full name , the Henry G . “ Hank ” Grundstedt San Xavier Mining Laboratory , jointly run by the Lowell Institute for Mineral Resources and the University of Arizona ' s Department of Mining and Geologic Engineering , is distinctive as the only such test mine in the United States with a working vertical shaft . It was a private mine that produced silver , lead , zinc and copper until 1952 . The UArizona College of Mines operated one shaft in 1958 and has owned it since 1975 . It is structured as an operating mine that students work , including holding positions of mine manager , safety manager , shift foremen and hard-hat miners . They participate in mine development , unit operations and maintenance . Since the first blast at the end of November 2020 , work on a new decline at San Xavier has steadily progressed . Phase 1 consisted of the establishment of the 15 ft by 15 ft portal with the length having passed 360 ft and approaching the first turn . Once the end of the first corner is reached , air flow sensors and thermometers will be installed as well as some crack meters . The expansion is a turning point for the SX mine and will facilitate getting more tools and machinery underground . The students ’ experience will be much closer to what they see once they actually join the industry , and more research will be possible . Further into the project an additional 1,150 ft of tunnel are planned to connect to the historic workings . Two JH Fletcher machines have been used — a N3112 bolter and J101 diesel-electric jumbo which is applicable to narrow vein mining applications in headings up to 22 m .
efficiency , because now the rigs are working twenty-four hours a day , seven days a week ,” says Yarunin .
The holes drilled in the underground mines have three diameters : 89 mm , 102 mm , and 152 mm . Before the installation of remote control and teleremote software , Apatit JSC Kirovsk Branch drilled 6.5 km per month of the 102 mm holes . After the installation , this figure increased to 7.7 km . For the 89 mm holes , the company went from 11.5 km to 13.5 km .
“ This is a significant increase in productivity ,” says Yarunin . His words are echoed by Onuprienko : “ Such automation has led to better drilling quality . This in turn improves the breaking quality , and by extension the production volume . Thanks to the Epiroc software , we can monitor the entire rig , analyse when , where and why the rig is standing , and identify potential damage ,” he says .
Epiroc says Apatit JSC Kirovsk Branch is pleased with the safety improvements and increased efficiency and plans to buy four more Simba rigs this year . Two will be used at the Kirovsk mine and two at one of its other mines . “ We also want to create a single technological command centre to control all Simba rigs from one location ,” says Yarunin .
Komatsu ’ s new hard rock drill line-up
Komatsu Mining recently unveiled a series of new underground hard rock drilling solutions . Starting with the battery-powered ZJ32Bi medium-class jumbo , this new unit offers reduced-hose and hoseless boom options to help reduce downtime from chafed and damaged hydraulic hoses . This is the first of a new set of machines where ( B ) is for battery and ( i ) for intelligent . The company states : “ Engineered to address the issue of downtime due to hose damage , the ZJ32Bi features a game-changing design with options for reduced hoses ( six per boom ) or completely hoseless booms . An advanced computer control system offers semiautonomous functionality with built-in operator augmentation features when in manual drilling mode . And the quality of Komatsu Montabert drifters coupled with drill feed technology rounds out the drilling end of the machine .”
It is also available in a diesel model ( ZJ32i ) with reduced or hoseless boom options . The new ZJ32Bi machine was available Spring 2021 . It represents also the beginning of Komatsu ’ s journey to offering fully autonomous underground hard rock machines – things have come a long way since the MTI acquistion in 2014 .
A note on the hard rock rebranding overall . This is a new model so is coloured Komatsu yellow . For existing models , the branding
will change from Joy orange to Komatsu yellow , and the nomenclature will now align with Komatsu brand standards . In the new product line overall plan , which includes yet to be launched models , a one boom ZJ31 jumbo and ZB31 bolter are also listed , which are expected to come in both battery and diesel versions , which using the new nomenclature would be the ZJ31Bi / ZJ31i plus ZB31Bi / ZB31i . The ZJ31 replaces the old one boom DR-1SB and the ZJ32 the old two boom DR-2SB . These products it says were built to help transform hard rock mining operations in need of both small and medium classes of machines . “ All of these workhorses are founded on proven drilling technology developed over more than a hundred years in the mining industry ,” says Komatsu .
But it is the common platform approach that really stands out . “ What ’ s truly different and unique about this product line is a common platform design . In fact , you might say that the common platform approach is like the multi-tool of mining of hard rock bolting and drilling . The platform offers 100 % design commonality between bolter and jumbo from the rear skirt to the outer boom structure .” Komatsu says this common platform between bolter and jumbo is an industry first . Everything up to the outer boom is identical , making for a seamless conversion from bolter to jumbo , or vice versa .
The inner boom of the ZB21 small-class bolter for example can be swapped out for a drilling feed system , effectively converting it to a jumbo . The same with the ZJ21 . This inner boom can be changed out for bolting . And the common platform approach goes beyond the drill attachment . Even the controls are the same . The universality of the controls was intentionally designed to help benefit mining operations from a training and maintenance perspective . Komatsu said the diesel version of both the ZB21 bolter and the ZJ21 jumbo are available to order now , with a battery option rolling out next year though it is unclear as yet if these will be referred to as ZJ21B / ZB21B or ZJ21Bi / ZB21Bi . The ZJ21 replaces the old VRII machine .
Komatsu stated on the Z2 class machine controls : “ The hydraulic pilot control system comes with universal bolting and drilling controls . The universal control platform allows for simplified user training and adoption across both drilling and bolting models . We ’ ve heard from many customers that their operator and maintenance skillsets are declining due to an aging workforce , remote sites and a cyclical
The Komatsu Mining ZJ32Bi features a game-changing design with options for reduced hoses ( six per boom ) or completely hoseless booms
44 International Mining | JUNE 2021