Projects
SINKING OF 2 FREEZE SHAFTS FOR URALKALI
Sinking of two freeze shafts in Russia for a new mine of Uralkali OAO with a diameter of 8 m, located 150 m from each other.
The new Ust-Jaiwa mine is located in the Berezniki/Solikamsk area, about 200 km north of Perm, on the west side of the Ural mountains. Approx. 10 million t of ore per year will be mined, to be added to the actual production of the 5 other existing Uralkali mines.
The final depths of the shafts are 465 m and 422 m respectively. The water-bearing overburden was frozen down to a depth of 245 m. This required 45 freeze holes per shaft with high drilling precision requirements.
The construction of the two shafts was basically done in parallel but staggered by about six months. Shaft sinking and equipping works were completed in December 2019.
The sinking work was done using the final headframe and double-drum sinking hoists, which were disassembled after completion of the construction of the shafts. The sinking and lining work was performed using a multi-level work platform, operated by 2 sinking winders.
Shaft construction proceeded in several sequential steps in the frozen part of the shaft:
- Sinking of the foreshaft to a depth of 40 m
- Installation of the complete sinking equipment
- Sinking and preliminary concrete lining to a depth of approx. 245 m
- Construction of the freeze shaft lining foundation and installation of the tubbing lining segments up to the shaft collar.
Further sinking to the sump continued by progressively excavating, installing the concrete lining and construction of the shaft stations.