dutch auction on close

Was watching the trading all afternoon, and it looked like someone was accumulating.

Then on close a whole lot of large random orders came on the market for the buy and sell. Around 2.5m ended up being traded at 10.5cents (up 5% for the day). It all seem very strange. Volume up.

Perhaps this was an end of month thing (options/CFD's?) OR the beginning of something?

Can any seasoned market players provide any further insight?

Gus