SHAFT SINKING platform that include asset maintenance , operational effectiveness and autonomous operations ,” he said . “ Insig has the capability and technology to build the required digital mining models for real-time enterprise reporting and business forecasting that comes from transparent , aggregated and timely information from our project sites . This means better connectivity for equipment intelligence , personnel and plant through underground instrumentation .
“ As we move forward , the information capture will be endless and it will allow us to utilise this information across all aspects of our business , from tendering to execution to controls and reporting .”
When it comes to hardware , Cementation Canada has also been continuously evolving , with its renowned large-diameter raiseboring team continuing to innovate .
A snapshot of this was seen on the Solvay Chemicals # 5 shaft in Green River , Wyoming , USA , where the company , with the help of Sandvik and Micon , recently completed a full faced raisebored shaft down to 459-m depth .
This project , Cementation Canada says , was significant for several reasons : n It was one of the largest raises ever pulled in the Americas ; n It was completed without incident ; and n It involved the use of a reaming head that could be diminished in diameter rather than manufacturing different diameters of outside wings . It is the latter element that has the potential to change the way raiseboring projects are carried out in the future .
Due to the need for the concrete liner thickness to increase as the depth of the Solvay Chemicals # 5 shaft increased , the initial concept was to complete a pilot slash raise with a raisebore drill and then slash from the top down to achieve the differing diameters .
Cementation instead proposed a full face raisebored shaft solution with variable diameters for each section , collaborating with Sandvik on a reaming head able to provide a flexible solution to carry out the task .
The final design of this reaming head allowed for five diameter options , going from a maximum of 8.1 m , down to 7.5 m , in increments of 168 mm . This used a reamer that consisted of 12 individual sections , 46 cutters and weighed 61,689 kg .
Following completion of 21 m of deep collar excavation and lining , and a 0.4-m diameter pilot hole drilled using Cementation ’ s Strata 950 Raise Drill and Micon ’ s rotary vertical drilling system ( RVDS ), the team settled on three diameter options . This saw the first leg of the shaft reamed to 7.9-m diameter for 179 m of shaft , followed by
7.6-m diameter for the next 87 m of shaft and 7.5-m diameter for the final 163 m of shaft to surface .
“ I don ’ t think this has ever been done before ,” Kohtakangas said . “ You can ream up at a certain diameter , drop down and change the reamer head and carry on the raiseboring , but that takes time . We didn ’ t have to do that ; all we had to do was take off the outside section when needed to bring it back to the required diameter .”
The raiseboring teams at the Solvay Chemicals # 5 shaft have now handed off to the shaft crews to complete the lining , but the company continues to be busy across the Americas on several projects .
At BHP ’ s Jansen project in Saskatchewan , it is carrying out the post-liner excavation , steel and
equipping for the two shafts already sunk at the potash project . The company is also carrying out some shaft guide realignment work for Hecla Mining at its Lucky Friday mine in Idaho .
With a modest number of greenfield projects coming through the pipeline , Kohtakangas had a parting technological thought that , he believes , could change the dynamics in favour of developing more shaft-supported mines in the future .
“ I have challenged our group to look at how we incorporate battery-electric technology into shaft sinking ,” he said . “ If you look into these sinking plants , they all require lots of power , which , typically , in a greenfield project where shafts are involved , is not going to be available until some type of high voltage transmission
SEPTEMBER 2022 | International Mining 85