there is research into this: Why following selling doesn’t work...

there is research into this:
Why following selling doesn’t work

It makes intuitive sense to me that following director selling isn’t very useful.
A director may sell shares for any number of reasons:

• To get the money to buy a sports car
• To pay a tax bill
• To meet his or her divorce proceedings
• To diversify a portfolio

In contrast, about the only reason anyone buys shares is because they think they will go up in price.
The exception is ‘token’ share buys by directors who are trying to signal to the market they have faith in their company, when perhaps they don’t.
The professors exclusion of trades under £20,000 in size probably got rid of most of this buying from all but the richest directors.

http://monevator.com/director-share-buying/

at the end of the day, so long as coal stays strong for a few more months, there is more money to be made from this....

for every guy that sells a stock, there is someone who's buying it... both people think they're right...