[Sudbury mining] Quakes occurred near Creighton – by Carol Mulligan (Sudbury Star – January 12, 2016)


Two seismic events that occurred before 6 p.m. Sunday in Sudbury have been reclassified from slight earthquakes to rock bursts, and their location has changed from east of the city to three kilometres northwest of Lively.

Vale recorded two seismic events 500 and 800 feet north of Creighton Mine, which were felt in the community about 5:40 p.m. The first event occurred about 7,680 feet underground and the second at 7,400 feet underground, said Vale spokeswoman Angie Robson.

The 7,680-foot level event registered a magnitude of 3.1Mn and the second event registered a magnitude of 3.3Mn, according to Creighton’s ground control system.

All workers at Creighton were brought to surface as a precaution and no one was injured, said Robson. Operations resumed at the mine Monday and there didn’t seem to be any significant damage the operation, she said.

The vibrations that occurred in the community weren’t a result of a blast at Creighton, although seismicity can often be associated with mining.

“In this case, the seismicity was of a higher magnitude than we would typically see. So while seismicity can be common, the magnitude of this event was not a typical occurrence and (was) felt by members of the community,” said Robson.

Because seismicity can be associated with mining, and can have deadly consequences on underground workers, Vale has a sophisticated ground control system, and it takes measures and precautions to deal with seismicity to protect employees and minimize the impacts felt by the community.

For the rest of this article, click here: http://www.thesudburystar.com/2016/01/11/quakes-were-actually-rock-bursts-near-creighton-mine

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