Schuttmann does not seem to have aged much in the forty to fifty years between the intro and the main story.
When they discover the presence of Anthracite at the mine, a character announces they've found C15H11O (which is the elemental composition). However, he pronounces it as C15, H11, "dash zero", when it should be "oh" as in the letter, which stands for oxygen.
The team standing directly over the metal grates covering the coal fire is unreasonable. The escaping gas would be toxic and the heat unbearable.
The keep's 'Kentucky' license plate reads neither the state, atop, nor the county name, on a blue swath, below.