Mastermyne CEO Tony Caruso said it was the company's focus on a safety culture that was delivering its good performance.
"There are an increasing number of sites completing significant periods of injury free work," he said in a company presentation.
"Leading safety indicators continue to guide our efforts."
The six sites that are injury free for 12 months for Mastermyne are Peabody Energy's Wambo mine with 1744 days, BMA's Broadmeadow mine with 1669 days, Anglo American's Grosvenor with 835 days, Whitehaven's Narrabri mine with 408 days and Tahmoor with 274 days.
Caruso said that there were seven sites injury free for the previous six months.
To maintain safety standards and skills levels, Mastermyne commissioned a second Mynesight training facility in Wollongong New South Wales.
The facility includes a simulated underground coal mining operation, which trains entrants to the underground coal environment.
The facility also allows access to the Wollongong coal operations in the region to provide induction and refresher training to these workforces.