Maybe they don’t feel like going through every load searching for these kind of things:
https://en.wikipedia.org/wiki/Coal_torpedo
Interesting. I had never heard of a “coal torpedo” before.
Modern boilers don’t burn lumps of coal. The coal is pulverized in a separate area in a battery of (usually) ball mills. This pulverized coal is then blown into the furnace and burned.
They might lose a mill or two, but the plant itself will keep running just fine.