Well I would say that both DML and OXR have got a lot of potential in the long run. Maybe he just wanted to cash up some stock. He used to be a large holder (I assume he still is)in PDN and the recent fall in that must hurt.
When Taurus Holdings is buying in its a good sign, especialy as the Chairman of DML - Gordon Galt is also a Director of Taurus. He is in a position of knowledge regarding DML's future.