What we did;
• drilled a rock hole for shaft dimension. Ø 200 mm, total length 152m. Into this hole we installed shaft pipe material.
• drilled a rock hole for shaft dimension. Ø 150 mm, total length 131,5 m. Into this hole we installed shaft pipe material.
• drilled a rock hole for shaft dimension. Ø 165 mm, total length 57m. Into this hole we installed shaft pipe material.
The drilling executed inside the mine was done with little space several hundred meters down from the surface. The precision of the drilling was demanding.
To execute this drilling we shortened the boom for our Casagrande C6 drill rig. Maximum element length for drilling was 3m. The precision demands where high and therefore the position of the drillstring was measured several times. The measureing of the drillstring position was done with a gyro. The drilling of the rock holes was a success and we hit the area marked for the coming shaft.
We drilled the 152m long hole from above the ground with this shaft, the challenge was to get the area between the rock hole Ø 200 mm and the Ø 140 mm injected since we could not plug the bottom of the shaft due to no access to that area. We had to develop a method to keep the grout from flowing into the mine through the drilled rock hole.
Sotkamon Porapaalu Oy’s knowledge was utilized to fulfill the clients needs in this project. We have several years of experience in rockdrilling holes and injecting of steel pipes in the holes to finalize the shaft construction.