Eagle Mountain – Woodfibre Gas Pipeline Project

Geotechnical and geophysical tests

James Lota, FortisBC

September 25, 2014

Welcome

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

Where are the tests being proposed?

3 boreholes in the Estuary

2 boreholes in the dike

1 borehole outside the

Estuary

4 boreholes along

Finch/Industrial

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).

What is a borehole?

Heli-portable drill eliminates

need for clearing of

access trails

10” diameter20m – 70m deep

Core Sample

Non-Reactive Bentonite “Plug”

Approx. 30m x 30m safe workspace is required

Example of core samples

Typical borehole testing equipment

Heli-portable drill rig

Typical borehole testing equipment

Track mounted drill rig

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.

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.

Ground Penetrating Radar (GPR) environmental impacts

• Transmits radio waves into the ground to detect subsurface features.

• Non-invasive and relatively quick

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.

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.

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”)

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

Proprietary and Confidential 19

Thank you