BOULDER, Colo.--(BUSINESS WIRE)--Zayo Group Holdings, Inc. (NYSE:ZAYO), a global provider of Bandwidth Infrastructure services and a leader in long haul dark fiber, today announced plans to extend its long haul dark fiber network between Salt Lake City and Sacramento. The network expansion will add more than 800 route miles to Zayo’s owned long haul network which spans more than 16,000 route miles across the United States and Europe. The project is currently under construction and is expected t