The primary issues stemmed from a poorly maintained mounting system, evidenced by:

• Inadequate anchor bolt lengths and the use of previously installed short bolts, which failed to provide sufficient clamping force.

• The presence of contaminated, cement-based grout that had lost its capacity to support the pinion gear base frame effectively.

• Significant misalignment of motor and pinion shafts caused by structural weakening of the foundation.

Alphatec Engineering’s solution involved a complete removal of the old base frame to access and replace all compromised elements.

The repair strategy included drilling deep injection holes to enable high-pressure pumping of Alphatec® 342 resin, which was used to fill cold joints, voids, and fissures in the existing concrete foundation.

Deteriorated grout was meticulously chipped away to expose a sound substrate, ensuring that subsequent repairs would bond effectively.

New anchor bolts, wrapped in PE foam and supported by Alphapads®, were installed to provide enhanced clamping force. The baseplate and pinion base skid were then regrouted using Alphatec® 800 epoxy grout, while chock grouting of the bearing pedestals was completed with Alphatec® 170.

A multi-jack bolt tensioning system (Superbolt™) was employed to secure the assembly with the precise clamping required for optimal performance.

After the initial repairs, precise measurements, levelling, and alignment adjustments were made to verify that the mill’s mounting system met the required tolerances.

Formwork was installed and sealed with epoxy putty prior to the grout pour, ensuring that the new material made full contact with the underlying concrete. Once the grout had cured adequately and the tensioners were re-tightened, the project was successfully concluded.

The rehabilitated foundation significantly reduced vibration levels and restored proper alignment, thereby safeguarding the SAG mill’s operational efficiency and minimising the risk of costly downtime.

This comprehensive foundation repair highlights the critical importance of effective maintenance in heavy industrial operations and demonstrates Alphatec Engineering’s expertise in delivering high-quality repair services in the mining sector.