Sigh. Here we go again.....
As a long term resident of the general area and having flown out of and into Richmond for many years in a previous life, I find myself repeating exactly the same stuff I did when this was last touted. And the time before that. And the time before that. And the time before that.
Keg was spot on. Sydney prob30 = Richmond pea soup. The runway and approach config is very limited by both terrain, and the townships. You could, in a moment of madness, build a longer runway towards the south, which will be great fun for all in the roaring westerlies which dominate many parts of the year (the last one blew my chimney flu cap off!). The other option would be to frog-march the 6-7000 residents of Richmond somewhere and demolish the township, as the threshold of 10 is a stone's throw from the built up area. Or you could have much fun knocking down the Sebel Hotel, digging up the golf course, and terra-forming Rickaby's Creek to get more length to the east (which will impress the hell out of the residents of historic Windsor township).
My other thought was go to the north. Easy. Just fill in the lowlands between the base and the Hawkesbury river with 68 ft of dirt. And you still get to join in the fun with the roaring westerlies, because after all, aren't all long main runways built perpendicular to the local prevailing wind?
Richmond is capable of handling most long-haul aircraft
Yes, a 747 could takeoff from here............with enough fuel to make BNE.
Anyway, I don't expect bureaucrats will heed any of that.