In deed time will tell but going of what has happened since the MRRT was announced there is little to indicate the fears will be realised.
If anything the level of investment in the mining industry is so high it's having a negative effect with the high value of the AU$ making our exports too expencive for starters. In WA the demand for housing has pushed vacancy rates to record lows & forced up the cost of rent.
There is no logic to the idea the MRRT will hurt the mining industry when they are crying out for the need to import workers.