I'd rather get to the point where we are removing these trash threads than simply just locking them. It's better to do that when they don't have any replies, and before they become a problem.
Agreed, but we run in to the problem of not enough mods again. I frequently report newly created threads for being spammy, low value, duplicate questions, etc. Sometimes these reports aren't acted on for 24 hours or more, by which time there can easily be 4-5 pages of spam replies.
The question remains also why a section so heavily moderated such as the mining section gets three mods whereas things like bitcoin discussion gets 1 (and that's a global mod so it doesn't really count) and project developement has no mods...