MINCO gold and silver explorer.... the facts

Not an investor in this sector before, but was reading an article on one of these freebie "subscribe and we will tell the you the secret" mailshots which talked about the long term trend of silver and copper. I also understand that silver and copper seem way out of line with the long term trend ratio with gold. I have had a look round for intvestments and this stock was one I came up with. Yields and PE's that I normally look for don't count in this sector. I came up with a list that looked attractive:
SLW silver wheaton - Canada
CRC copper resources corp - UK
ACU african copper - UK
MIO - Minco PLC - UK

Can any one help with a brief description of the Minco story? I also read above that the directorship has changed? Are their better competitors and what sort of risk do you see with this one?