Mopani Copper Mines – Ventilation Shaft Grouting – Kitwe, Zambia, 2018-2019

Sovereign performed grouting of the Synclinorium Primary Ventilation Shaft at Kitwe, Zambia. This shaft was designed and constructed with the ventilation fans installed at the surface. There was water ingress into the shaft at various horizons in the upper 120m from surface, and the total inflow was originally estimated to be in the volume of 5000 liters per hour. The water entering the shaft had a very corrosive effect on the fan steelwork, and therefore was detrimental to the performance and the projected life span of the fans.
Sovereign designed a drilling and grouting program involving vertical holes drilled at locations outside of the shaft that intercepted the water leaks without removing of any of the fan infrastructure.
A shaft camera survey was performed to determine target drilling depths and a total water inflow water measurement was made prior to commencement of grouting. The actual water ingress into the shaft was measured at 10,130 liters per hour, more than double the 5000 liters per hour anticipated prior to the time of construction.
Upon completion of the grouting program the final water ingress measured at the bottom of the shaft was 82 liters per hour, better than a 99% reduction!
Drilling and grouting was carried out over a 90-day, incident-free period via down-stage pressure-grouting through 12 vertical diamond-drilled holes using a combination of Sovereign’s proprietary NOH2O® grout and Ordinary Portland Cement grout.