big sell down

Does anyone know what the big sell down was about.

There were two sellers for 250k at 22c for the past couple of days which kept prices below 22c. They moved down to 20.5 mid afternoon and finally one dropped to 20c where he sold 90k or so. The trading was fairly heavy all afternoon (over 1m shares) with heaps of bots (trading each way but more down than up) and just about every kind of trade possible. I havn't added up the trade at auction, but at one stage there was going to be about 1.6m traded.

Final shares traded was just under 3.3m.