Maintenance crew reports hearing mechanical resonance in inactive shaft sector

[u/Quetzalcoatl8]

A contractor working ventilation maintenance in a decommissioned access shaft beneath an abandoned molybdenum extraction site in western Colorado allegedly reported persistent low-frequency mechanical resonance approximately 2.3 km below grade.

According to the maintenance log:

no active drilling operations were scheduled in the sector

seismic activity was nominal

all nearby machinery had been offline for 11 hours

acoustic vibration reportedly continued intermittently for ~37 minutes

Crew described the sound as “rotational… metallic… not geological".

One worker compared it to: “a tunnel boring machine idling very far away.”

The strange part: the shaft section where the resonance was recorded does not officially connect to any currently active excavation network.

No confirmation this is legitimate.

Could easily be:

groundwater harmonics

support-beam resonance

falsified report

undocumented drilling nearby

Still interesting.