in your google maps search window will take you right to it... image date is march 2004. and judging by the berm of dumptruck piles that surrounds the whole site(follow the first well used road turning off to the east...it's also on the west side)... i really question just how "secret" they were trying to keep it... at least back then anyway. and if you explore using google, it's clear that its part of a much larger area that is clearly a military reservation of some sort...i'd say a bombing range and/or multi-purpose range for live fire training. but there was NO attempt to conceal the material removed in the excavation. however...those two that you marked DO look interesting...that whole area looks like a military storage depot for explosives and or "other" volatile materials. there's literally hundreds...makes it a thousand or more, igloos...not counting the earth revetments, in an area encompassing well over 40 sq. miles.
Russia says kills six suspected militants in North Caucasus (Reuters)
from the article: Report: New Iran nuclear facility will be operational soon