Lost tools in the mine

[Hallorenkugel2]

Often, when I've choosen my tool, the mine shut down without a reason. When I open the mine again, my tool is lost - without using! By this way I already lost a lot af this tools - yesterday 3 !!! I'm really not amused! Because it isn't easy to get tools and one of them was made by myself!!
Do has anybody the same problem?
Please, fix and change it!