(CNN) -- The Crandall Canyon mine collapse that killed six miners in Utah last summer lasted only seconds and was not caused by an earthquake, a new study says.
The University of Utah study, released Monday, contradicts mine owner Bob Murray's claims that a quake triggered the collapse at the coal mine.
And by concluding the initial collapse was over in seconds, the study provides some comfort to families who feared that miners may have spent agonizing minutes trying to escape.
The August 6 cave-in in northwest Emery County killed six miners. Three rescuers died 10 days later in a subsequent collapse.
The initial collapse registered as a 3.9-magnitude seismic event.
"As seismologists, we're as certain as we can be that the seismic event registered as a magnitude-3.9 shock was due to the collapse of the mine and not a naturally occurring earthquake," said Walter Arabasz, director of the university's Utah Seismograph Stations, in a statement.
The collapse occurred quickly, the study said -- even though it registered on seismograph readings for several minutes as the mine shafts continued to vibrate.
"The collapse probably happened within just a few seconds and was not a long, drawn-out affair," said the study's lead author, seismologist Jim Pechmann. "There would have been no time for anybody to get out of the way. It would have happened too fast for that."
The study also said the size of the cave-in was nearly four times larger than what federal investigators initially thought.
The team presented its findings to the Mine Safety and Health Administration and for publication in the journal Seismological Research Letters.
The study will not be published for several more months. And while scientists do not usually release studies until they are published, the researchers said they made an exception in this case because of high public interest.
The Mine Safety and Health Administration has launched its own investigation into the collapse. Those results have not yet been released.