Not a pressing issue but a little confused.

[Naguib]

I'm going through A Dictionary of Basic Japanese Grammar methodically, which, granted is probably not the best method, but I'm a bit bored of the podcasts... So I came across this sentence:

このレポートはあとけつろんをかくばかりだ。
The sentence supposedly means:
The only thing left to do with this report is to write a conclusion.

I just was wondering what "ato" was doing in the sentence - it's not being used as in "ato de" and the word isn't written in the kanji form for ato (後）so i was wondering what role it was playing in this sentence and if it meant something other than after (dictionaries were of no help) Thanks!

[QuackingShoe]

It's mentioning what's left to do. I still just think of it as the generic 'after' meaning, but I guess really it's more complicated. At any rate, it's what's left after what you've done already (or after whatever else was mentioned).

[amost]

I agree with the poster above. An example of just "ato" used in the same way:

あと３０分行きます。　(I'm going in [after] 30 minutes)

so...

あと結論を書く seems like "after writing a conclusion...."

[QuackingShoe]

(can't type Japanese atm)
No.
ketsuron wo kaita ato would be "after writing a conclusion." ato ketsuron wo kaku is "After (the other thing), will write a conclusion." We're just not saying after what. Presumably, 'everything else that's already been done,' and this is what's left.

People use this when makings lists of all kinds, including courses of action. Do this, do this, ato, only this and this.

[Javizy]

I agree with the poster above. An example of just "ato" used in the same way:

あと３０分行きます。　(I'm going in [after] 30 minutes)

so...

あと結論を書く seems like "after writing a conclusion...."

あと30分 means '30 minutes remain, 30 minutes left, another 30 minutes'. After 30 minutes is 30分後 (さんじゅっぷんご). So your sentence might sound better like 出発まであと30分/30分後に行く or something.

残りあと30分
フリーライブまで、あと30分！
あと30分くらいしか時間が無い

[amost]

I agree with the poster above. An example of just "ato" used in the same way:

あと３０分行きます。　(I'm going in [after] 30 minutes)

so...

あと結論を書く seems like "after writing a conclusion...."

あと30分 means '30 minutes remain, 30 minutes left, another 30 minutes'. After 30 minutes is 30分後 (さんじゅっぷんご). So your sentence might sound better like 出発まであと30分/30分後に行く or something.

残りあと30分
フリーライブまで、あと30分！
あと30分くらいしか時間が無い

I apologize. That must have been the context in which people use "ato 30pun"