Kiena Mine Paste Pant

Kiena Complex is a gold mine located on Parker Island surrounded by the Lake De Montigny, a few kilometres east from the city of Val D’Or, Quebec. The mine lay dormant for several years until a discovery of a large gold deposit 1000 meters below surface reactivated the mining activities.

In the process the miner decided to build a new paste plant. Pierre Gagné Contracting (PGCL) was hired to install foundation piles and casing in two existing boreholes.

The foundation piles for the new paste plant were of two sizes, 24 inches and 36 inches diameter for a total of 37 piles. They were installed through the overburden into the bedrock with one foot embedment. Depths varied from 8 to 28 feet.

The casing install consisted of two phases - phase one was to widen or ream the existing borehole, phase two was the install of casings. When the existing boreholes were drilled borehole #2 steered off and gradually connected into borehole #1. A decision has been made to ream borehole #1 from 10 inches to 30 inches to accommodate both casings. The majority of the reaming, which started from the mine 330 meters below surface going up, had been done using a 30 inch reaming tool. When the geology proved to be too challenging for the aforementioned tool, PGCL sourced a 24” push/pull bit with three hammers to complete the remaining to the intersection of the boreholes.

Once the borehole widening was completed PGCL proceeded to install the casings. Each casing segment was 20 feet long and had to be welded together. To hold them in place PGCL fabricated an engineered steel bowl with a support structure able to hold the weight of the entire assembled casing. The bowl was used to accommodate casing slips that wrapped around the casing and held it in place. A special sleeve with high grade pins was utilized on the drill rig to lift and lower the casings.

All tasks were accomplished by using the Foremost DR40 drill rig.