Channel Lining | Eagle Gold Mine, Canada
Erosion Control and Channel Lining for Two Spillways
Project Overview
In May 2019, Concrete Canvas® GCCM (CC) was installed as an erosion control liner for two spillways. The first connects the heap leach pad to an events pond and the second, an emergency spillway for the events pond. The spillways formed part of the Eagle Gold Mine operated by Victoria Gold, located in northern Yukon, approximately 200km from the Alaskan Border. The local area is subjected to seasonal variance of 20° to -30°C.
Solution
The spillways were designed to convey any overtopped heap leachate in the case of extreme weather events. The spillway would only likely experience any flow in the case of a 200-year storm event. The site is heavily monitored by the Canadian mining regulator and Ministry of Mining.
- The main spillway is approximately 500m in length with profile sections of 5-8m at 7-15% gradient.
- The emergency spillway is approximately 140m in length of varying width at 50% gradient.
Alternatives to Concrete Canvas® that were considered included poured concrete with an applied coating. This was discounted due to concerns about the logistical requirements and installation rates.
Design & Installation
- Consultant used the Concrete Canvas Ltd Hydraulic Shear Calculator to design and specify the GCCM for the channels
- CC8™ Bulk Rolls specified for main spillway <7.5% gradient
- CC13™ Bulk Rolls specified for the main spillway >7.5% gradient and the emergency spillway
- Channels excavated and compacted prior to deployment
- Transverse layup
- Perimeter edges secured in anchor trenches
- Screwed and sealed overlap joints
- Intermediate rock anchors installed at 1.8m centres along every joint of the emergency spillway to resist hydraulic shear (reduced to 0.5m centres at the sharp corner)
- Hydrated using a water truck and hose
Summary
The onsite contractor installed the material at a rate of 750 – 850m² per day in temperatures of 15°C. The consultant valued the Hydraulic Shear Calculator provided by Concrete Canvas Ltd in order to specify the GCCMs and check the intermediate anchor requirements and the client is satisfied that the spillways were installed to meet the program.
Useful Resources
CC8™ and CC13™ was installed as a spillway erosion control Iiner for two spillways in Yukon, Canada
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