I work not too far from Chinchilla in the Coal Seam Gas mines in the area, stayed in a camp there for a few months, now I stay over in Dalby (about an hour away).
There is no doubt that at the moment Chinchilla would be a good investment and give you positive gearing for any investment you have there. But the mines will not last forever, and when the people finally do leave the area, you will find a significant drop in your property value. In fact with the amount of housing they did build in Chinchilla, I imagine there will be hundreds of vacant houses when the mining companies do eventually finish up and leave the area. The population there simply will not be enough to fill up the houses for a very long time. Supply will be high and demand will be low, ingredients for very low property prices.
Myself personally I am not interested in investing in mining dominated areas, and although Chinchilla isn't a "pure" mining town, it is very significant part of the economy, so once it is taken away, so will the economic viability of the property in the area.
Dalby is slightly bigger (15,000 people compared to 3,000 people in Chinchilla), but again it is mostly dominated with the mining in the area, I would almost rather invest in Toowoomba, which although affected by mining at the moment, is still building in population even without the influence of mining. And it is only about an hour away from Brisbane outer suburbs. Toowoomba would also provide a lot of the maintenance resources required for the mining sites, as you can imagine the maintenance of the mines is going to last a lot longer than the actual construction. This is in regards to coal seam gas anyway.
