Mt. Cobalt drilling results, page-262

The ASX continuous trading session ends at 4pm.
The market then enters the pre-CSPA (Closing Single Price Auction) period which lasts from 4pm to 4:10pm.
During this period the selected few can enter, amend and cancel orders in the order book. I'm not sure who can do this but I do know that CFD Traders with DMA (Direct Market Access) accounts can get involved.
There isn't any buying or selling during this phase, just people placing, amending and cancelling offers and bids in the order book.
At 4:10pm the market enters the CSPA phase and ASX auction algorithm goes through a process of matching so that the maximum number of trades are settled at the most competitive level to produce the closing auction price.
Hence the prices you see on the order book from 4pm to 4:10pm are meaningless. The price that counts isn't determined and the order book isn't reconciled until after 4:11pm when the CSPA phase ends.
fyo there is a similar process prior to the market opening as well.