are you sure you will not charge users for the withdrawal fee for all coins found on your website?
That part is a bit too good to be true
[even if they were using micro-wallets and judging by some of the comments, I don't think they are].
Is it allowed to withdraw winnings without a deposit?
Yes:
Anyway, OP should create a FAQ page.
They already have one
[look for the "Help" page instead (it's under the "support" section)].
All funds of deleted dormant accounts including their balance and any bankroll investments are forfeited by the user and assumed by the operator.
Personally, I'm not a big fan of seeing such terms in any platform
[it's not fair (there should always be a way to retrieve those)]!