Honestly, in my opinion, it's not that bad if your quarry happens to find lava. As long as you visit it form time to time you will notice when it happens and you can throw a bucket of water at it then. As soon as it's obsidian the quarry will go there and mine that part as well, so you don't really lose anything on it.
Although you probably have to find any other water springs it run into and take them out in a timely fasion.
EVE Online characters:
Daedalus II ex-CEO TOGOA, Daedalus III slave of Daedalus II
Little Molok Asura Engineer
"Trying is the first step towards failiure" - Homer Simpson