Fireball seen over Safford Mine

I was heading North into the Safford Mine this morning. I had just passed the main gate and looked up to see an incandescent colored fireball streaming at a E-NE heading from the San Juan pit to the Lone Star pit.  The object was roughly 300 feet above the haul road and seemed to follow it directly.
I originally mistook it to be a low flying helicopter but the object had no anti-collision lights. My suspicions were confirmed when the object passed in front of the Southern mountain peak (Peak 2) of the Lone Star pit. The object disappeared as it passed in front of the mountain.
The object covered the roughly 3 mile distance in less than 3 seconds. It had the beginnings of the curved shield shape forming in front of the object like those typically seen in objects entering the atmosphere.
Earlier this morning there was an unusual amount of helicopter traffic in the Gila Valley. I live in the flight path for the local hospital so, I thought there may have been an accident on the highway or at the mine, etc. The local med evac chopper is a small helicopter. The traffic heard this morning sounded more like multiple heuys hovering over my neighborhood. The noise diminished slightly when I went to get in the car. There were no helicopter lights visible in the sky at the time.