When I see newsreels of Soviet military parades, it seems clear that the Russians put emphasis on mobile launchers as opposed to fixed installations.
That is my thinking. The first missiles didn't have the range to be fired from as far away as Dyatlov pass. They were mobile and also above ground . They could take several hours to get ready from an incoming attack , the silos were an escalation to be ready to retaliate at a quicker time frame . Whilst potentially receiving a nuclear attack , the silos would still be operational.
As I understand it , it was missiles first and their range , then the nuclear war head capability, then silos .
The problem I envisage with a silo at the Dyatlov pass or within that region is the distance for the range of striking capability of the missiles at that moment of time in 1959. At some point they would have to design and build a silo and test it , not the missile but the launch from the underground silo. When the silos were eventually built and operational, they consisted of 3 silos and a HQ. Fuel, operating room , living quarters and all the logistics that would come from an independent silo base.
Both sides of the cold war didn't have the data of accuracy of the missiles . Cities were the main targets along with known military air fields . Accuracy was not the Achilles heel at that time , it was the speed and cost of being able to retaliate. I think both sides had missiles on stand by but the fueling and cooling , along of a lot of stuff I don't fully understand was the problem. Every day was a cost in labour and man power to nurse these missiles to be ready or on stand by.
Mobile units have an advantage because they could pop up anywhere , the negative is they weren't a push button instant solution..
http://www.astronautix.com/r/r-14u.html "
Development of the modernized R-14U (universal) version, which could also be launched from 'Chusovaya' complex silos, was authorized on 30 May 1960. The authority to design the silo was issued two weeks later. The first test launch from a surface pad was conducted on 12 January 1962, followed by a series of launches from the silos from 11 February 1962 to October 1963.
In the silo-launched version, each regiment consisted of two divisions, each division being a single emplacement with a technical point and three silos. The launch complex was designed by TsKB TM under the direction of Nikolai Krivoshein. The hardened command and control technical point was modified from that for the R-12U, with each silo placed at least 100 m from the other about the technical point. Each silo was 30 m deep, had an inner diameter of 4.0 to 4.5 m, and was hardened to withstand overpressures of 2 kg/cm2. The silo design was accepted for military service on 15 June 1963.
The first R-14U silo division became operational at Priekule, Latvia in 1964. Further complexes were at Nerchinsk and Yasnaya in the far east, Dzhambul in Kazakhstan, Glukhov and Belokorovichi in the Ukraine, and Karmelaya in Lithuania. By 1965 a total of 97 R-14 and R-14U test or operational verification launches had been conducted, and around 100 mobile and silo launchers were operational.
The R-14U, in mixed deployment with mobile launchers, was retired in the late 1970's.
Maximum range: 4,000 km (2,400 mi). Initial Operational Capability: 1960"
I have underlined the word 'Chusovaya' because that is the name for THE silo specific to the r-14u missile. Other missiles had different silo names . ( After rivers I think)
At 2nd northern, zina writes in her diary
"
2nd North is an abandoned village, nobody lives here at all, and what beautiful places! It's just Chusovaya. The stones on the banks are some cliffs, limestone, white. Today we go a few km along the Lozva River, and then we pass to the Auspiya river."
Coincidence probably as I think zina did a river hike or some activity there before. However, avoiding conspiracy if I can , the case files talk too much about missiles and the code names , with a small leap of faith , I think it's good reason to make the case files classified.
I am having a stab in the dark here but both sides , west and east had been spying on each other for years. Long ranch missiles and nuclear warheads were a new game in warfare, both sides were paranoid which is understandable given ww2 and the shifting politics in Europe . The US and UK had Communist sympathisers, students were a target by both sides.
Food for thought...