Epic, crushing, "ancient war" sounding death metal/metalcore/deathcore whatever genre that has that heavy, epic, and throttling sound.

To be honest, there aren't too many that I've heard that sound exactly like Heaven Shall Burn - though that's a good thing, it means they are original and unique. I would be intrigued to hear bands that are similar to them nevertheless. You'll have better luck looking for bands that come from Germany.

Caliban would be one band you could look into. They are more breakdown heavy, and their later material is generic metalcore. Shadow Hearts is their heaviest material.

Neaera has been described as being similar, I haven't heard too much from them though.

Last One Dying's album "The Hour of Lead" sort of has an epic style to it.

Bolt Thrower is one of the biggest influences on Heaven Shall Burn, though they are obviously not metalcore. There is definitely no harm in listening to Bolt Thrower!

Even though I already know all the bands you listed thanks anyway for replying, oh and believe me I enjoy me some Bolt Thrower

check out Cataract from Switzerland, crushing thrashy metallic hardcore. They are very much influenced by Bolt Thrower and Slayer btw.
http://www.youtube.com/watch?v=sYk1cPyG4qw

I second this one, despite the shitty vocals

I'd second Neaera, especially their earlier material. Rising Tide of Oblivion has some of those Epic modern melodeath riffs laden in pretty thick and the lyric content is pretty deep and meaningful, stuff like Rwandan genocide, post war anxiety attacks etc.