BUTTE, Mont. -

Butte-Silver Bow announced Monday it will close the historic courthouse rotunda to begin restoration work on the dome.

The dome in the courthouse is made up copper and glass, and the two are separating from each other, creating a safety hazard.

The county selected Bovard Studio to do the work -- the same company that worked to restore parts of the state capitol building in Helena.

The work is expected to cost around $220,000 and could take five to six months.

The courthouse rotunda will officially close Tuesday; no other parts of the court will be closed.