Roger Warren has been granted permission by the national parole board to spend more time away from his halfway house for medical treatment.
The board says its decision was made after 71-year-old Warren was hospitalized for pneumonia and doctors said he needed to stay longer for tests.
Warren was imprisoned for setting off an explosion deep inside the Giant Mine during a bitter strike in 1992, when nine replacement workers were killed as their ore car trundled over a trip wire.
Documents from the board say Warren must follow a series of conditions and a parole supervisor may revoke his release if there's a risk to the public.
Warren was being held at the Mission Minimum Institute, east of Vancouver, when he was granted day parole last June, when he was transferred to a halfway house at an undisclosed location.