The drilling of the sixth and final borehole into a Utah mine began Thursday as part of the last effort to save the six trapped miners.
The hole is being drilled in an area where the miners were last believed to have worked, according to The Associated Press.
"This is the last hole," said Bob Murray, CEO and co-owner of Murray Energy Corp., at a news conference Wednesday evening, according to CNN. "If we don't find anybody alive in that hole, there's nowhere else that anyone…would know where to drill."
Previous holes drilled into the Crandall Canyon mine have failed to show signs of life.
Murray expressed little hope that the sixth hole will be any different, saying it was "totally unlikely" any signs of the miners will be found.
Six miners have been trapped in Crandall Canyon mine since the cave-in Aug. 6. Rescuers were hopeful at first when an earlier test indicated good air level and after detecting a "noise" or vibration last week.
Rescuers continued to be optimistic even after three rescue workers were killed and another six injured last Thursday during a third cave-in since the initial disaster.
However, last Sunday's air test coupled with over two weeks of rescue efforts and no strong evidence of life forced officials to consider an end to the rescue operation.
The fifth borehole completed this past Wednesday found only a six-inch space between the roof and the rubble. No noise was heard from the hole after a microphone was lowered. A video camera and oxygen readings have not yet been performed in the fifth hole, said Jack Kuzar, a district manager for the Mine Safety and Health Administration, according to AP.
Murray said he has filed with federal regulators to permanently close and seal the Utah mine.
"Had I known that this evil mountain, this 'alive' mountain, would do what it did, I would never have sent the miners in here," said Murray, according to AP. "I'll never go near that mountain again."
Family members of the miners have criticized Murray and federal officials for not declaring the mine too dangerous to work in prior to the tragedy, saying that there were many signs indicating the mine's danger. Relatives are also angry that Murray will not continue the rescue effort or at least send rescuers in a capsule to retrieve the bodies.
Officials suspended all underground work after three rescue workers died last week while trying to tunnel their way to a cavity where they thought the miners were located.
"We are so appreciative to all of the rescue members and their families. Don't get us wrong, we are so appreciative," Jackie Taylor, whose daughter dates one of the six missing miners, told NBC's "Today." "Our love and our prayers go out to all of their family members. But our family members are still under there. They're underground. We need that closure in our lives also."
Sonny J. Olsen, an attorney and spokesman for relatives of the miners, said the families want to find the bodies despite how long it may take.
"Regardless if it takes three months to wait for the seismic activity to stop, they want some method to go down and get their families," Olsen said.
The three cave-ins since Aug. 6 are all believes to be caused by "mountain bumps," or shifting grounds which cause chunks of rocks to fall from the wall. Crandall Canyon mine is said to be a "live mountain" with occasional "mountain bumps."
The sixth borehole is scheduled to be completed by Saturday, according to CNN.
The trapped men are: Louis Alonso Hernandez, 23; Manuel Sanchez, 41; Kerry Allred, 57; Carlos Payan, in his 20s; Brandon Phillips, 24; and Don Erickson, 50.