This is not the best title, however I am not sure how this was used. I found this on King Island. It appears to by made of concrete, has an axle and a frame. It appears to be designed to be pulled by a tractor. Perhaps it is some sort of pressing device.
You can buy a copy of this image as a print at http://alexhowen.redbubble.com/sets/63978/works/3153350-2-agricultural-press