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Eagle Mountain – Woodfibre Gas P ipeline Project

Eagle Mountain – Woodfibre Gas P ipeline Project. Geotechnical and geophysical tests. James Lota, FortisBC. September 25, 2014. Welcome. Why are g eotechnical & geophysical tests n eeded?.

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Eagle Mountain – Woodfibre Gas P ipeline Project

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  1. Eagle Mountain – Woodfibre Gas Pipeline Project Geotechnical and geophysical tests James Lota, FortisBC September 25, 2014

  2. Welcome

  3. Why are geotechnical & geophysical tests needed? • Common engineering practice when planning underground construction method such as horizontal directional drilling (HDD). • Minimize environmental impacts and construction risk: • Squamish Estuary • Highway 99 at Industrial Way

  4. Where are the tests being proposed?

  5. 1 borehole outside the Estuary 2 boreholes in the dike 3 boreholes in the Estuary

  6. 4 boreholes along Finch/Industrial

  7. What is a borehole? • Commonly used in engineering site assessments around the province. • Used to collect soil samples to determine subsurface conditions of the area. • Narrow vertical shaft bored into the ground to a depth of 20 to 70 metres (~ 10” diameter).

  8. What is a borehole? Heli-portable drill eliminates need for clearing of access trails Core Sample Non-Reactive Bentonite “Plug” Approx. 30m x 30m safe workspace is required 10” diameter 20m – 70m deep

  9. Example of core samples

  10. Typical borehole testing equipment Heli-portable drill rig

  11. Typical borehole testing equipment Track mounted drill rig

  12. Minimizing environmental impacts • Boreholes in estuary were handpicked to minimize clearing requirements. • No clearing – Dike or Finch Drive – Industrial Way. • FortisBC will replant any disturbed areas with native vegetation.

  13. What is geophysical testing? • Three types of testing are proposed: • Ground penetrating radar (GPR) • Electric Resistance Tomography (ERT) • Multi-channel analysis of surface waves (MASW) • All the above technologies consist of portable equipment that workers can easily carry in the field.

  14. Ground Penetrating Radar (GPR) environmental impacts • Transmits radio waves into the ground to detect subsurface features. • Non-invasive and relatively quick

  15. Electric Resistance Tomography (ERT) • Images sub-surface areas by measuring resistivity with low-levels of either AC or DC current. • Helps determine the geometry, lithology, hydrology and/or petrology of subsurface geologic formations.

  16. Multi-channel Analysis of Surface Waves (MASW) • Exploration method used widely since the 1990s. • Measures seismic surface waves generated from a seismic sources (such as sledge hammer). • Results characterize or estimate stiffness/hardness of materials at depth.

  17. Minimal environmental impact • Hand clearing of brush and deadfall, as necessary for worker safety. • Required by Worksafe BC to avoid injuries. • Animal walking trail width is sufficient. • Doesn’t require cutting down large timber (e.g. > 3” – 4”)

  18. Environmental Management Plan (EMP) • Although geotechnical / geophysical tests have minimal environment impact, FortisBC has prepared extensive EMP that includes: • Environmental monitoring • Archeological monitoring • Environmental controls such as: • Schedule – access • Tree and vegetation • Fire • Drilling waste • Hazardous materials • Waste management and disposal • Air • Noise • Environmental incidents and spills • Restoration

  19. Thank you Proprietary and Confidential

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