According to the Trust in Energy 2015 report by Edelman, the Energy sector is the most targeted industry sector by activists. Chemicals are on the 4th and Mining / Metals on the 5th position.

The presentation can be found here 

On slide #19 you find that most targeted energy companies are Shell (#2), TransCanada (#3), Chevron (#7), Gazprom (#8), BP (#10), ENEL (#12) and Exxon Mobile (#14)

Chemical companiy Dow is ranks on the 13th position, where Du Pont is to be found on number 18

Mining companies do not appear in the top 20