My take is that tarriffs killed the ability for this mill to compete for its foreign customer's business, which was the majority of the business. After tarrifs there were not enough domestic customers to keep the doors open.
The mill that will meet the foreign needs will not be American because the dont have to add on tarrif increases.
Thus the jobs, business tax, payroll tax, and wages reinvested in the economy will all be going to some other nation.
This scenario reads towards an outcome that is more Manhattan Project than Philadelphia Experiment.