No it was an AT mine because if you look at Ork mines such as the ones on the Ork Kommando, they use that model. However they also use the same model for their demolition charge ie. multipurpose model because someone didn't want to make another model.

I've played against IG.
And the most effective use for their Tanks was to sit behind cover and shell my forces at a distance (I've been wiped out a few times with that tactic).
That's how IG work. They're mainly a Mid-to-Long-Range force with some Melee capability. Plus being at such range it is hard to attack them without serious speed or Deep Striking nearby.

The Russ is the IG Main Battle Tank, and should be treated as such, with front and side armour that requires either one of the limited weapons which are strong enough to penetrate (Lascannon for example) or are energy Lances whose characteristic neutralises some of the armour protection (reducing it to 12).

Yeah its a good tactic until you charge up the board on bikes, and pretty much decimate the gun line from left to right, getting there can be a bit tricky but once your there, Melta guns before the charge then clobbering time power fisting the rear armour. Bikes do have there disadvantages, but I like them.

How do you get past the fortifications? You know. When they're parked behind an Aegis Defence Line for instance.

last time I just had to negotiate rocky terrain, you can still assault on the aegis wall, if need be turbo boost up the board. I haven't tried this tactic myself but using Kosorra khan and his flanking rule, come in turn 2 flank the enemy in land raider with your terminator's a bit of risk there, but if you hit the sweet spot. alternatively I've used scout bikes with homing beacon before to deep strike terminators. also used a drop pod with ironclad dread (I know, the lore thing white scars they don't have them) and 2x meltas to take out rear assets, this also help by drawing a lot of fire, from my biker squads that were pushing up the board.

A meltabomb is their only anti-tank mine, Orkz (at least last time I played them on the TT) get frag stikbomz, krak stikbomz, buzzersquig stikbomz (which are all thrown) and a meltabom (which is the only sticky bomb they have), the tankbusta hammer is also a meltabom on a stick.

Up until the 4th edition meltabomz and meltagrenades were thrown weapons, like the rest of the grenades, after that point they changed the meltagrenade into a meltabomb and made it a sticky mine used in close combat against vehicles.