Subcontractors for the City of Nanaimo are busy plugging holes in downtown鈥檚 underground. 

Crews from the city, Western Grater Contracting Ltd. and Bedrock Redi-Mix Ltd. closed the intersection at Bastion and Commercial streets Thursday, Jan. 16, to fill voids encountered under Bastion Street in October when test drilling was done as part of downtown underground infrastructure renewal work.

The discovery halted work in the immediate area and moved elsewhere on Commercial Street while further testing was done to help determine how best to deal with the gaps that had formed over decades, after old coal mine shaft ceilings likely caved in deeper underground. 

Bill Sims, Nanaimo鈥檚 general manager of engineering and public works, said the city is pumping the slurry into the underground gaps to fill the voids. 

鈥淚t鈥檚 going better than we expected,鈥� Sims said in an email. 鈥淭here have been no really large caverns to speak of, mostly cracks and fissures. We鈥檝e drilled about 25 holes, so far, and are filling them with a wet 'flowable' grout. We鈥檒l use about 15 to 20 cubic metres for this work.鈥�

The city anticipates the work is about halfway through the drilling and grouting process, according to Sims, which will involve drilling and filling another 25 holes with 20 cubic metres of grout, given the current information about conditions underground.