Thanks. Do they push the sand from the face down to the bottom then? Seems as if they must have far more courteous golfers down under than on a lot of courses that I play. Pretty hard to justify not raking bunkers like these. . .
The sand is just compacted down so it is almost solid so even walking all over it doesn't have too much effect or at least shouldn't, so you don't really have to push sand down to the bunker base. When the greenstaff rake the bunkers, they first use a broom or board to smooth the faces raking up or down as there is so little loose sand on the faces it shouldn't make too much difference, they then rake the base with metal wire rakes, and finally smooth over the route out of the bunker by pulling any loose sand upwards away from the base to give a neat finish. In normal play though if bigger marks are made on the faces made you sometimes see a line out of the bunker where someone has walked and raked over it (they only leave normal rakes in the bunkers no boards or brooms!) so it doesn't always look quite as pristine unfortunately, but these are usually out of the back of the bunker so they are out of view for a lot of the time. Smaller marks can often just be smoothed over with a foot if you can reach from outside the bunker and not make too much mess.
To get the hard faces the greenstaffs buggies/gators are driven up the faces (carefully) to compact the sand down so it is only a fine dust really on the top of the hard packed surface which needs to be smoothed over when brooming or boarding the faces. There is also very little sand in the bases of the bunkers compared to most courses as well.
It is all to do with the type of sand on the Melbourne sand-belt and in particular its particles size which makes it compact in that way. It isn't found anywhere else or so I am told which is a pity as I love the style of the bunkering there.
Here is a thread all about it, where I asked the question why the style isn't used elsewhere;
http://www.golfclubatlas.com/forum/index.php/topic,49099.0.html