[Anaraxes]

Strength-base melee weapons do damage based on the ST of their wielder, not because of their own mass. (If you want to drop the hammer on someone, literally, then you could use the collisions; it's just a weight.) Weapons have a minST rating (shown as "ST" in the equipment tables), and the ST you can actually use to inflict damage with that weapon is capped at 3x minST. So, the point of a gigantic, massive, weapon is to really raise the "maxST" you can effectively apply with it (also raising the minST).

There's a chart in the "Big Weapons" section of Supers that shows stats for large "staff-like" and "maul-like" weapons. This sounds maul-like. The maximum value in that chart is a 432-lb version, minST 76, damage sw+24. To reach 2400 lbs, that table would need two or three more rows. There's probably a formula somewhere, but since I'm too lazy to look those up or reverse engineer it, it looks like minST moves up by about 1.45 per row (or 2.1 = minST 160) for another two. Weight doesn't look as consistent, but it's roughly a factor of around 2 per row, so that minST would be for weapons between 1728 and 3456 lbs. +8 dmg per row, so sw+40 (at minST 160, that's 19d+40, or 30d+1 if you apply adds-to-dice).