problems with using RFID technology in underground mining

The RF power emitted by RFID is far from being able to burst anything to flammes. Passive tags shouldn’t be able to produce sparks, but I am not aware of regulations or tests that need to be performed.
The most sensitive part will be the reader, which, like all electronic device has a possibility of sparking, but I guess hermetic casing could do the trick on a safety point of view. Anyhow, the power used is pretty low, and I find it extremely improbable that RFID can cause combustion. Do you have the link to the articles?

What might be a little more problematic will be range with UHF or microwave. If you fear combustion, then I guess you have particles in suspension or gases, and they might disturb the radio field at these frequencies, depending on their nature.