Whale Tail Dike Rehabilitation Grouting Success-PPT Presentation

PPT Presentation

Pdf Summary

The presentation describes the rehabilitation grouting program for the Whale Tail Dike at Agnico Eagle Mines’ remote Whale Tail Mine, 160 km north of Baker Lake, Nunavut. The dike’s instrumentation showed rapid warming in bedrock and filter zones that correlated with lake-water temperatures, suggesting possible seepage through the bedrock and cutoff wall. During dewatering, measured seepage reached 600 m³/h, with turbidity observed in the collection channel.<br /><br />Agnico Eagle formed a technical grouting committee to develop a response. The initial target was to reduce seepage by at least 40%, to approximately 360 m³/h. The team used a phased approach: install a two-row grout curtain to 5 m depth, completing the downstream row first, and deepen the upstream row only where needed.<br /><br />Work began in November 2019 under severe winter conditions and in a logistically challenging, remote setting. The method involved staged drilling and grouting, with primary, secondary, and tertiary holes, pressure-based adjustments to grout consistency, and repeated reaming and grouting until specified refusal criteria were met. The program used cementitious grout mixes, including calcium chloride and a thixotropic admixture, and tracked grout take, volume, pressure, and mix for each hole.<br /><br />From early November 2019 to March 25, 2020, seepage measured at downstream weirs fell from an initial range of 350–600 m³/h to approximately 100–150 m³/h. This represented a reported reduction of 75–80%, exceeding the original target despite the harsh conditions and active water head.

Keywords

Whale Tail Dike

rehabilitation grouting

seepage reduction

Agnico Eagle Mines

Nunavut

grout curtain

bedrock seepage

dewatering

winter construction

instrumentation monitoring