Azovstal Steelworks - Why Was It Hard to Capture?

Azovstal Steelworks is almost a fortress with miles of tunnels and bomb shelters deep underground.

A short video here looking at Azovstal Steelworks and just why this was such a hard nut to crack for Russia. The answer, simply put, is it is huge. It spans four square miles of a sprawling warren of buildings, warehouses, smoke stacks, railway lines, furnaces and factories. Even the surface is an urban warfare nightmare with coverage for troops of soldiers, thick-walled warehouse to hide heavy armor and extremely difficult to navigate. 

Looking at photos of the plant before the war, you can see how many alleyways, tunnels and buildings there are to conceal soldiers and all the possible positions for sniper teams and anti-tank teams to hide. You could hardly have planned for a better fortress than Azovstal. The Russians have been pounding it for weeks, leaving it a smoking ruin and yet they failed to dislodge the Ukrainian forces.
 
The surface is just a fraction of Azovstal’s size. Below the surface, is a vast network of tunnels and bunkers built during the Cold War to safeguard the plants workforce in case of an attack. The tunnels are inpenetrable by bombing and the Russians have tried—Tu22Ms have dropped bombs on it with little effect. Even Putin refused to order is men inside—perhaps realizing it would be a blood bath. 
 
Why? Well, take a look at this small graphic showing a cut away map of the tunnel network. According to information available, there are six reinforced floors and over 24km long tunnels under the plant.. The largest structure is under the blast furnaces. Under these furnaces is a “skip put” which is a huge underground tunnel which trains travel through. The depth wasn’t clarified, but the first level is estimated to be around 10-15 meters and the last level is between 30 to 50 meters. These facilitieis have an independent water and electricity system. 
 
At the height of the siege of Mariupol, the network of tunnels were thought to contain around 1,500 soldiers—a fearsome fighting force even on the surface. The tunnels also have access to the surface, allowing the soldiers inside to perform guerrilla-like strikes against the Russian army.

Now, the plant’s director in a BBC said Five of the bomb shelters can withstand hits from a nuclear bomb, and the thickness betweem the ceiling of the first tunnels and the surface is at least 8 meters. The bomb shelters themselves are even deeper underground.
 
This second graphic shows more information with another cutaway. So, number 1 – we have tanks and artillery pieces located on the surface inside the plant. These are likely hidden in the warehouses and factories—these themselves are tough, sturdy structures providing a lot of protection. 
 
2 shows that snipers can hide in buildings in the plant. Just looking at photos shows that it is a sniper’s paradise. 
 
Now we get underground itself, with number 3 showing the location of the Cold War bunker—very tough to penetrate with bombs. 
 
According to the source—civilians are between the second and fourth floors, as well as supplies of food and ammunition. 
 
5 shows the independent food and electrical system mentioned. 
 
6 – is access to the lower levels—there are over 24km of various tunnels 
Number 7—on the bottom floor is where the soldiers are. 
 
Basically, this steelworks is a near impenetrable fortress, so it is no wonder that the Russian plan was to surround the plant rather than be foolish enough to enter. 
 

Now, there is a video allegedly showing someone exploring the tunnels, but I can’t post it as I don’t know if it is legit footage or not. But if true, it shows stairs leading down with many tunnels leading off. It is dark, with no natural lighting and even no artificial lights on the roof. Some of the side tunnels are extremely narrow.

It seems now that the soldiers are finally leaving Azovstal, but I thought it was interesting to see why it was considered such a tought nut to crack.