A very small number may have broken their word, however no bonds were signed. Some individuals went to the Far East and apparently didn't make the grade only to return to Oz. However most had been with the company more than 6 years, as 152 pointed out they left due to the down turn in the mining industry and were concerned about their jobs.
As far as crews are concerned the company normally has a morning and evening flight to the mines. So considering annual leave and standby's, 5 crews for every 2 aircraft would probably do it. Initially there would be a small number of typed guys to get the the ball rolling but as the number of E190s increases, Alliance pilots will be moved on to the 190 leaving F50 and F100 slots. These will obviously be filled with rated guys that they know. I have heard of one F50 "checkie" who can start quite quickly.
Best of luck to all.