the chopper had no numbers anywhere. Is this odd? Please note that our time is the time in Hungary where our friend and web chap lives. I will ask him to adjust.
I realize that cell service is fairly nonexistent at the mine, but if you have a smartphone, you can use the Flighradar24 app to find out the tail number of the aircraft, then potentially, the owner. Or, at least see where it took off from...
The government has been mapping power lines and geo sites for the last few years. I was part of the project using drones for close proximity scanning and imaging. Power lines are being imaged by homeland security and the interior department. White/Grey and yellow Bell Helicopters are used for this. If lucky you may spot the LiDAR scanner on one of them and a camera set on the other. Number 3 is what you have mentioned prior. Modified antennas for deep core scanning
.imaging and mapcoring.