on break:
    set {_Break-x.%player%} to x coord of the block
    set {_Break-y.%player%} to y coord of the block
    set {_Break-z.%player%} to z coord of the block
    execute console command "/fill %{_Break-x.%player%}-1% %{_Break-y.%player%}-1% %{_Break-z.%player%}-1% %{_Break-x.%player%}+1% %{_Break-y.%player%}+1% %{_Break-z.%player%}+1% minecraft:air"