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Pebble Project Facilities Would Be Unaffected by Recent 8.1M Earthquake in Alaska
Robust engineering design for key mine-site facilities reflects commitment to environmental ...
About this update from Northern Dynasty Minerals Ltd.
[{"type":"text","content":"Pebble Project Facilities Would Be Unaffected by Recent 8.1M Earthquake in AlaskaRobust engineering design for key mine-site facilities reflects commitment to environmental leadershipVANCOUVER, BC / ACCESSWIRE / August 10, 2021 / Northern Dynasty Minerals Ltd. (TSX:NDM)(NYSE American:NAK) (\"Northern Dynasty\" or the \"Company\") reports that its 100%-owned US-based subsidiary Pebble Limited Partnership (\"Pebble Partnership\") has determined the 8.1 magnitude (\"M\") earthquake experienced in Alaska on July 28, 2021 resulted in substantially less ground movement at the project site than the seismic events considered in the assessment of the stability of its proposed tailings facility designs.\"We determined the 8.1 M earthquake that occurred last month south of the Alaska Peninsula, about 300 miles from our site, created ground acceleration at Pebble that is 20 - 30 times less than the design earthquakes we've evaluated,\" said Ron Thiessen, Northern Dynasty President & CEO. \"To put that into perspective, the 8.1 M earthquake recorded July 28 is the largest seismic event in the United States in the past 50 years.\"‘Seismic risk' is measured as ground acceleration as a proportion of gravity (\"g\"). The Pebble Partnership has assessed seismic risk at the Pebble site so that proposed tailings embankments and other mine facilities would not fail under even the most severe seismic events, which are extraordinarily unlikely. This is a course of action that will continue throughout the state permitting process and life of mine.The extreme seismic events modeled to test the stability of proposed tailings embankments and other mine-site facilities at Pebble include:a repeat of the 9.2 M megathrust event that occurred in Alaska's Prince William Sound in 1964 (the second largest seismic event ever recorded);an 8.0 M earthquake occurring ~50 miles east of the Pebble Project site, similar to but of larger magnitude than the 7.1 M event that occurred north of Anchorage in November 2018;a 7.5 M event along the entire length of the Lake Clark Fault, including those portions closest to the Pebble site for which no evidence of movement for more than 10,000 years has been detected; and,a 6.5 M event occurring immediately below the proposed Pebble mine site, where no evidence of a fault exists.\"The highest ground acceleration at the ...