technical report on the nechalacho deposit, thor lake project ...

seven) have occurred more frequently along the west border of the province, adjacent to the
east side of the Yukon Territory, during the period of record.
Seismic hazard for the TLP has been examined using the probabilistic calculations as per the
2005 National Building Codes (NBC) for the site area released by Natural Resources Canada.
Seismic hazard is quantified using spectral acceleration, which is the amount of ground motion
for sustained shaking energy at a particular period. Spectral acceleration at periods of 0.2, 0.5,
1.0 and 2.0 seconds (equivalent to frequencies of 5, 2, 1, and 0.5 Hertz) are used to fully
quantify seismic hazard as Uniform Hazard Spectra (UHS). Although spectral acceleration is
considered a better measure of potential damage than the peak measures used by the 1995
code, the peak ground acceleration is still used for foundation design.
Ground motion probability is expressed in terms of probable exceedance of a given horizontal
acceleration or velocity over a particular time span. The probability used in the 2005 NBC is
0.000404 per year. This corresponds to an event with a return period of one in 2,500 years, or
a 2% chance of an earthquake causing horizontal ground motion greater than the given
expected value over a 50-year period.
The conditions at site are believed to generally consist of relatively shallow deposits of sandy till
(generally