Woohoo! First enchantment ever, first try!
Isn't unbreaking a bit of a waste on there? Drills don't break anyway.
I was wondering about that too. But, depending on how the energy consumption hooks into durability, maybe unbreakable provides a chance that power won't be consumed by a use? If energy tools simply rely on item durability, with the caveat that the item does not break when it reaches 0 (or, in my experience with nano armor, extremely low) durability, then unbreakable might still increase the energy efficiency of the tool.
Personally, I kind of think enchanting and IC should be incompatible, like sorcery and technology in Arcanum. Attempting to enchant an IC item would cause a spectacular explosion, on the order of a nuclear meltdown (maybe dependent on how much you tried to enchant it). The question would be whether you'd put a warning in it anywhere. Not having one would result in some hilarity when people started to report it, but putting in a warning (even an offhand comment of "we really recommend you do not try this") kind of defeats the purpose of having it. On the other hand, I have to admit it would be a seriously dick move: being unexpected, you didn't plan for it, so likely your entire home base and dozens of hours of work is destroyed.
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I wish the mods that added more types of basic blocks went the extra step of adding the 'sub-types' of the block. For example, it doesn't make sense to me that marble can make bricks, but not stairs or slabs. Basalt cobblestone can't even make bricks. Would also be nice if new materials could be interchanged based off a vanilla item; for example, being able to use the new gems of redpower in Balkan's new weapons (since they're not very useful otherwise). But I guess that's half the point of an API - rather than having to hack in new things and then having to specifically call those new things, you could instead code the new item as a "variant of diamond, with these differing stats, usable in all the things that diamond is used for" and by default other mods could use it, or recipes can choose to use only a specific flavor of the item (e.g. though sapphire might be a flavored diamond, some recipes may only be possible with a diamond, or a sapphire). Ho hum.