The BlockBreak Event is fired whenever a block is being broken.
You can cancel the event to prevent the block from being broken.

You will need to cast the event in the function header as this class:
crafttweaker.event.BlockBreakEvent
You can, of course, also import the class before and use that name then.

BlockBreak Events implement the following interfaces and are able to call all of their methods/getters/setters as well:

• IEventCancelable
• IBlockEvent

The following information can be retrieved from the event:

ZenGetter	ZenSetter	Type
ZenGetter player	ZenSetter ​	Type IPlayer
ZenGetter isPlayer	ZenSetter ​	Type bool
ZenGetter experience	ZenSetter experience	Type int

The following information can be retrieved from the event:

ZenGetter	ZenSetter	Type
ZenGetter world	ZenSetter ​	Type IWorld
ZenGetter blockState	ZenSetter ​	Type IBlockState
ZenGetter block	ZenSetter ​	Type IBlock
ZenGetter result	ZenSetter ​	Type string with value of default, deny or allow

ZenMethodes

• event.deny() Method, sets the event's result to deny
• event.allow() Method, sets the event's result to allow
• event.default() Method, sets the event's result to default

ZenGetter	ZenSetter	Type
ZenGetter position	ZenSetter ​	Type IBlockPos
ZenGetter x	ZenSetter ​	Type int
ZenGetter y	ZenSetter ​	Type int
ZenGetter z	ZenSetter ​	Type int