- The green borders aren't working for me, either use images, thicker borders or a softer colour. I see you're using CSS3 styling, and it's not always giving the nicest results in all supporting browsers.
- The logo has a nice serif font, yet the rest of the site uses a simple and unelegant sans serif. It's not always an option but try using a serif font.
- Line-height is too big
- Your header is too big, you can save some space repositioning the icons and searchbox.
* edit: some suggestions: *
--- resize the company logo at least to 70%
--- move the searchbox to the navigation bar, aligned to the right
--- move the icons closer to eachother and give them a slightly darker or lighter background
-- you should be able to cut the headers height by a fourth
* /edit *
- The green you use for texts is too bright, it's ok on my monitor but I can imagine some ppl having trouble reading it.
- The jobs page can benefit from a grid layout instead of just centering links under eachother.
- the upper right corner of your header should be a 90° corner, just like the logo.
- Not all jobs require you to run around with safety helmets

maybe a stock photo without one? a desk job?
* it's common practice to make article titles links to the full article, and use a smaller font for the "read the full article" link
* it's also common practice to make the company logo link to the homepage
+ the overal design is very fresh and easy to look at, it looks professional enough
+ It looks quite finished, button links, icons, etc... do a good job at that
+ no tables!
+ htmlstrict
+ good metas