This tunnel was discovered by the guys over at VT Exploration. You can read about it there.
This tunnel runs down the hill in front of Hillcrest, reportedly at a steep incline with no stairs or ladder. It then passes beneath the hissing manhole marked with an "H" on the other side of West Campus Drive. After observing the official utilities map and building floor plans, it appears that this tunnel connects to Agnew, with possible access to either the mechanical room or crawlspace in that building.
I will provide more information about this tunnel when it is available.