At this point of time, Blacketts had just about worked through the first 30 feet of boulder clay, which was used for brickmaking. The chimneys indicate that there were are least two sets of kilns which were coal fired. The pictures are clear enough to show the bogies (trucks on a miniature railway) that transported the clay to to the works. They were mostly cable hauled, excepted for the last bit were the labours would bush them to where the steam powered digger was working. This can be seen, in shadow, at the top middle of the picture. There is a white flare of steam coming out of the top.
This picture shows that my Drawing of Blacketts Brickworks, 1966 was pretty accurate.
Details courtesy of Fred Starr.