As I have always done, I stashed those heavy black rocks in my pack and put them in the garden at home. They never were given a second thought until a half decade later…

We’ve had two trips to the deserts of Nevada and explored mines and mill sites, hiked miles of ravines in California, and swung our detector coils over thousands of square yards of bedrock.

Within this area, about two million ounces of gold and fifty million ounces of silver have been mined. Faults, dikes, veins and fissures that carry the ore form a concentric radial pattern—like spokes on a wagon wheel—around the caldera core.

The type of mine dump that is best for metal detecting are the ones that consist of mixed sizes of rock and are located near some sort of excavation, commonly a shaft or adit. Sometimes the piles located along a trench dug by the miners can be productive as well.

We decided to check some spots that were pretty good to us on previous trips. The detector was deceptively simple with few buttons and auto-ground balance.