Double take

Last May I was in the middle of a field in Iowa with several friends having fun searching the site of an old fairground. 
My friend Chuck invited me up to Moline Illinois to give a talk at a metal detecting event and I met a lot of nice folk and Chicago Ron, just kidding Ron! 
The day after the detecting event a small group of friends got a chance to search the field in Iowa, after everyone spread out I hit the area I figured I had the best chance of finding something. 
I made a bee line for the biggest oak tree in the field, figuring that tree would have provided shade many years ago. 
The area was loaded with trash, mainly modern pull tabs and bottle caps, so I guess it still provided shade to people now.
I was told it was a good field for old silver coins, but being a beach hunter the small aluminum targets sounded just too good to pass up. 
The aluminum pull tabs sounded just like gold and I figured where there is silver there could be gold, maybe wishful thinking.
As I expanded my spiral search pattern away from the base of the old oak tree, I found fewer trash targets.
Until finally I heard a loud low tone followed by a quieter high tone through my Minelab CTX 3030 headphones.
Two targets I thought, before digging an obscenely large plug of dirt just in case the low tone was a gold coin.
And this is what I saw, an aluminum pull tab and the edge of a coin in the same area. 

I could have easily got frustrated and just moved on knowing it was a pull tab, but the high tone made me want to dig in the area.
Usually it is the opposite way around for me at the beach searching for jewelry, hearing high tones (coins) and not wanting to dig them until I hear a low tone (gold) in the area.
I talk a lot about hunting by ear, even if you use a metal detector with discrimination features out the wazoo and this is why.

A superb 1922 silver dollar, lost in the field who knows how long ago and helped to be discovered by a stinky old pull tab. 
The metal detecting gods work in mysterious ways, which is why you need eyes and ears to find this kind of stuff.
Your eyes as sight reading tools and your ears as detecting tools, I use the Minelab Cap to keep my head warm.
Heres the real point of todays blog, I heard both targets and even if I had not seen the edge of the silver dollar I would not have left the hole until I recovered the object making the high tone.
There is a big size difference between the aluminum pull tab and silver coin, but I wonder if I would have heard the silver coin laying on edge if it was a few inches deeper ?
Attractive targets like the aluminum pull tab may mask a much larger but deeper conductive target, another reason to always recheck your holes before filling them in.