SHAFT SINKING
At Agnico Eagle ’ s Odyssey project , in Quebec , Canada , shaft sinking advanced at an average rate of 2.5 m / d in the June quarter , according to the mining company
Herrenknecht says the SBC is equipped for hard rock up to 250 MPa UCS , with the machine able to carry out cutting , lining and mucking operations concurrently . It has been designed for shaft diameters up to 9 m and shaft depths of circa-1,500 m , utilising a similar pneumatic mucking system to the SBR that leverages the cutter disc ’ s circular motion to vacuum up material from the shaft bottom .
Herrenknecht is targeting sinking rates of 6-8 m / d with the SBC , with the company having
carried out 600 tests with different sizes of material , completing over 10 m of shaft sinking in 30-40 MPa UCS concrete with a demonstration rig that is 1:3 the size of the full-size machine .
Since initially demonstrating this rig in Schwanau , Germany , in early 2023 , both companies have been evaluating the options to deploy it in a shaft sinking project .
Sustaining the sinking skills
Greinacher ’ s colleague in Canada , Kevin Melong , Vice President of Shafts and Technical Services at Redpath Canada , views these mechanised developments as crucial for making the “ learning curve quicker and easier ” in the shaft sinking space , especially during busy market periods .
When asked to comment on the concerns of the skilled labour situation in shaft sinking , strata , we do not expect any further issues with the ground conditions significantly impacting production .”
Greinacher and his team , along with Herrenknecht , have two options to progress through this rock should the SBR ’ s performance be compromised .
The preferred Option A is to use “ partial blasting ” in 1.5-2-m rounds , in combination with the SBR ’ s pneumatic mucking system and tubbings . Should Option A not deliver the expected performance , Option B includes a “ full drill & blast ” setup where both Redpath ’ s indevelopment RD S100 and a “ hanging construction ” for a jaw crusher are attached to the second work stage of the SBR . This second option would see the company leverage a design for the S100 mucker with a rotable shaft excavator fitted on a 2.5-m-long telescopic boom that scoops muck into the crusher before the crushed material is removed from the shaft bottom by the pneumatic mucking system .
Greinacher said the company will start sinking in the Sherwood Sandstone using Option A , acknowledging that water levels and pressure , and expected ground conditions , were all factors to be considered .
While this takes place , Redpath Deilmann continues to progress with testing the S100 .
Outside of the two projects already mentioned , Redpath Deilmann is engaged in early study work for other major shaft projects in Europe and Asia , with at least two of these having the potential to deploy mechanised shaft sinking operations .
“ One of these could potentially feature the SBR , and there is potential to also deploy the SBC on one or two of the others ,” he said .
The SBC Greinacher refers to is the Shaft Boring Cutterhead : the hard-rock equivalent of the SBR that Redpath Deilmann and Herrenknecht have been working on for several years .
SEPTEMBER 2024 | International Mining