Anonymous
What we need to find and preserve is a list of the locations of all these required resources. Where are all the iron and coal (and what type of coal) mines and the clay you mentioned and so on. A list of all oil wells and known reserves of oil and the others. Surely our government has such lists. It seems likely that there may even be such lists published in a book every so often. Not sure how to start looking. Could start asking here: https://en.wikipedia.org/wiki/Colorado_School_of_Mines
Certainly, one day survivors could work through all the existing steel, but there is a lot of steel out there now. In a couple of generations a great deal of it will have turned to rust. Don’t know, can rust be reworked into good steel?
One easy to reach source of steel would be railroad rails. A group could gather hundreds or thousands of those and store them in rain proof barns. I would hate to salvage those rails before there is any hope of getting trains running again though. High on my list would be building or restoring a steam locomotive. The biggest problem with steam that I see is how to build a steam pressure gauge from scratch! The very earliest steam engines, before they made pressure gauges, had a tendency to blow up their boilers! Very near the top of the list of construction drawing to acquire is steam pressure gauges.