The most common and most likely answer to this crossword clue is the 6 letter word INTRAY
I
N
T
R
A
Y
Buddy explains!
The straight part
We know that "Is it in part dealt with (bit of pile going) before end of day?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case is it in part dealt with (bit of pile going) before end of day? = intray.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INTRAY mean?
INTRAY noun- A desktop organizer; inbox, in-basket.
- (by extension) The amount of new work yet to be done.