Llano is about 30 miles from where I live. There is no such structure in Llano nor much of anything else but remnants of a resort, gone 80 years, a post office and a some houses scattered along Hwy 138 and up into the backsides of the San Gabriel Mtn.'s.
Informants have mentioned underground tunnels and facilities in California at Edwards AFB.....Norton AFB, and Morongo Valley......
Norton is gone, but would have been a really poor candidate for underground anything. It is sitting in a rocky, alluvial fan of gravel and boulders, located at the junction of several mountain drainages and with a water table that would require constant pumping of facilities of this nature. the north edge of the base is the San Andreas fault and the San Jacinto fault line (and others) run through the property. If these ever were here, they have mysteriously disappeared now that the base belongs to the city of San Bernardino. Morongo Valley is another highly unlikely location. Morongo Valley is small, narrow, and thoroughly populated. It also sits astride, and is created by, the Pinto Mtn. fault. It would be more likely that something of this nature would be out on 29 Palms Marine base as it is HUGE and very few people get in there. As for Edwards, no chance. I'd know (that is all I am saying on that base). http://quake.wr.usgs.gov/recenteqs/FaultMaps/117-34.htm When one starts finding glaring holes like this, obviously the rest of the article appears equally flawed.
More data--especially facts--are better than less data, imho.
I do suspect the other side could offer explanations explaining both data sets.