Cementation Completes Large Raise Bore for Solvay in Wyoming
Cementation instead proposed a full face raise bored shaft solution with variable diameters for each section. They worked closely with Sandvik to design, engineer and manufacture a reaming head that could be diminished in diameter, rather than manufacturing different diameters of outside wings. Final design allowed for five diameter options; maximum of 26.67 ft, down to 24.48 ft, in increments of 6.6 in. The 26.67-ft-dia. reamer consisted of 12 individual sections, 46 cutters and weighed 136,000 lb.
Following completion of the 68-ftdeep collar excavation and lining, Cementation’s Strata 950 Raise Drill was set up over the collar and a 16-in.-dia. pilot hole was drilled with Micon’s rotary vertical drilling system. When the completed pilot hole was surveyed, the total deviation from vertical was found to be less than 4 in. over the entire length of the pilot hole.
Based on the pilot hole survey it was determined that the first leg of the shaft would be reamed to a 26.13-ft diameter for 588 ft of the shaft, followed by 25.02-ft diameter for the next 285-ft of the shaft and 24.47-ft diameter for the final 535-ft of the shaft to the surface.
Reaming of the shaft was completed on April 24 and the Cementation shaft crews are now in the process of completing the shaft lining. This raise was one of the largest ever pulled in the Americas and was completed without incident. Its success was the result of a collaborative effort by all parties involved in providing the best technical solution for the Solvay Chemicals No. 5 Shaft.