Confused

[Myles]

Hello all,
This is my 1st post since joining about a week ago. I am also watching many videos on learning and reading a lot. Enjoy reading about your finds. I want to tell you about today's hunt & my confusion. Hopefully someone can help. I am new to the field and have a 505. Still learning it. I was at an older abandoned home today (had permission). Was digging on edge of gravel driveway which was covered with 2b limestone to a depth of 6-8". Getting several signals close together indicating a quarter and a half at 6-8". After digging thru the stone to 8" the detector still said the targets were 6-8" below. My new Garret pointer indicated 2 targets several inches apart but the digging was very difficult. After making it thru the stone I came to a layer that looked like it may have been ashes from a stove, somewhat yellow and as hard as a rock. I could scrape it and it would shave off like very fine play sand but could barely be broken by the trowel. I tried digging around the edges but could not do so due to depth of hole and small circumference I dug.
Here is where I need help. Could it possibly had been ashes that turned that hard? Why did detector continue to tell me depth was 6-8" when I was at that depth but the pointer still said lower? Is "air" distance the same as depth in the ground? I gave up and will go back when I learn a little more. Thanks for any help.

 

[mwaynebennett]

Often times a larger target, such as a soda can, will provide misleading signals. If I raise the coil about 6-8 inches above the surface and swing and I still get a reading, then I know there is something BIG down there. I then usually ignore it. I could be passing by an iron kettle full of doubloons, but that is a risk I am willing to take.

Mark

 

[Ed in SoDak]

If your coil won't fit into the hole, the depth reading won't change. If there's no metal or mineralization in the soil, removing it won't change what the detector sees.

Ash can be detected due to the carbon being conductive enough to alter the magnetic field. Detecting in campfire remains can be very noisy. Some factories spread out their cinders and burned waste on the ground and it can make the entire area useless to detect.

Lime can have a high carbonate content and might also have trace metals and minerals that leach from the stone over time.

In my own area, fine native iron grits can accumulate enough to cause a signal. It always reads as being 6-something inches deep and moves around as you dig. My pinpointer can barely locate one of them, but the larger coil on my detector picks them up in their quantity. Drag a strong magnet (placed in a baggie) around in the loose soil and see what it picks up.

In a yard, you can have utilities of wire or pipe. There may be lots of rebar embedded in any concrete slab.

Raising up the coil as Mark suggests is a good tip. Note the ID, you may find similar stuff elsewhere.

-Ed

 

[Myles]

Thanks guys. I'll try them out.