I did a more aggressive internet search. This seems not possible given physics, as well as not documented (at least in the US) in the CDC Mine Accidents Database [0], which has been recording mine accidents since before the discovery + invention of AM radio.

Edit: The physics

- (lambda) = c / 1,620,000 Hz = 185 m :: 1.62 MHz is what I derived as a near max possible accidental frequency able to be produced by AM equipment

- 185 m / 2 = 92.6 m :: this is half a wave length

In order to resonate (let alone have enough power to "cook", which I didn't even look at because the wave can't even resonate), a tunnel must be at 92.6 m (fundamental) or 185 m wide or tall (2nd harmonic). Most tunnels are ~5m/3m wide/tall at most.

Dusted off my physics from my minor in college so someone feel free to correct me.

[0]: https://wwwn.cdc.gov/NIOSH-Mining/MMWC/MineDisasters/Table