I got it even though my mine is closed. When I collected the first dynamite it added to my maxed out 25. So now I have 26. So IF they ever open the mining up again we can use the Dozer dragon to stockpile dynamite at least. Assuming it's not just a glitch and it lets us continue to collect dynamite.
To make the Dozer dragon more attractive to buy, the mine should not close when one has max out on the expansion. The benefits of the coins and apples should still be available when mining.
Had to nab this while on sale:
1.) it's cool looking
2.) who know's when it will go on sale again? may be awhile
3.) dynamite!!!
4.) dynamite depot and concussion cave both have the capacity for 2 dragons so you know TL will more than likely issue another bomb and dynamite dragon. At least that's what I'm hoping.