Fwiw…..
A long time ago, I rec’d a phone call from the General Manager of a mine/mill/smelter complex. He told me I would soon have a visitor from an alphabet agency who wanted to ask me a number of questions regarding site security.
He showed up the next day and we talked for a couple of hours. He wanted to know how to disable a large complex like we had and he focused on the underground mining operations.
He seemed to know very little, but he asked interesting questions. He thought the best way to disable our mine would be to disrupt our power supply and cause the pumps to shut down and cause the mine to flood. Not so, we had had a long labor strike and our incoming power lines were dynamited. Lost power for a week and the mine did indeed flood. We got the power on, dried out the mcc’s and motors…. Replaced fluids in the crushers and got the mine up and running in 3-4 days.
He was disappointed and told me that was not long enough.
Anyway, upshot was that two targets were of interest to him. The first was to disable the hoisting equipment and the second was to damage the our power transformers. Both the hoisting mechanism and the transformers were not “off the shelf” items. Loss either could cause a multiple month long shutdown….. maybe longer.
He left pleased.
You guys are right about the transformers…. Replacing large transformers take quite a while and they are generally not easily repaired and restored to service.
