Hot ground?

[Yooper]

I was metal detecting in the old park yesterday and came across an area that was absolutely full of iron, or so I thought. I got a decent signal and dug up a bunch of coal. The coal was very close to the surface and there was a ton of it. There was also a clad penny in there.

Does coal cause a detector to go crazy? The area was about 50 by 50 feet.

 

[txbluesman]

I don't know for sure, but I would assume YES. I know that at one of my local parks, there is a small area that is virtually undetectable. Every detector that I have owned goes nuts when going over this area. I finally dug a hole to see what was under there. At about 4" there was a layer of some white chalky substance about 2" thick. I have no idea what it is but it sure causes detectors to display false and erratic readings.

 

[jeff & Maria]

Coal as well as pieces of road chunks will give you a big headache. The tiny pea gravel will also.

 

[raptro5618]

I live in an area that was the heart of coal land and yes it can cause you some trouble. I have posted here several times looking for advice because I have dug many deep holes that only have coal or ashes in the bottom. Pinpointers are worthless in coal except for the X-1. I just got the SE and it seems to be better at seperating the coal noise from good coins at least on my last outing.

I will relate this one event so maybe others have an idea. Site where I have always had trouble with coal or coal ashes. Got a good id. Dug down 10 or 11 inches and nothing was there. Signal still was strong and steady but nothing but dirt and ash. I use the probe and off to the side I get a signal and there is a quarter. I pin pointed carefully and even over the open hole it pinpointed where I dug. Now I wonder if those other empty holes misdirectedd me or they just looked like something they were not.

 

[Boony]

Hi Guys,

I have found that in "HOT" ground that if I reduce the sensitivity way down (something around 5) it reduces the hits from the ground and lets the signal from coins etc stand out much better (works for me)

All the best.....Boony

 

[Yooper]

Thanks for the input Boony. I think this coal area is small and was used to store coal for heating old buildings that used to stand nearby. I will try a 5" coil in the Spring and turn that sensitivity way down too.

 

[RonNH]

Coal will definately give a signal. I detected around a train depot and was constantly getting coal hits. I'd rather have it in my stocking!!! Ron

 

[Crispytoo]

A while back I was hunting at a park that had some railroad tracks up on a hill nearby. I ventured into the brush and undergrowth below them and started getting intense silver signals (upper right corner) and proceeded to dig. Nothing. A few semi-large smooth oval rocks had come out of the hole so I ran the coil over them and they blew my eardrums out. The Bullseye probe (being a PI) didn't pick them up at all. I them started to find these rocks sporadically throughout the park. I tried knocking my sensitivity down but these pesky buggars wouldn't be ignored. I was using my 5" stealth coil at the time.

 

[john paul]

n/t

 

[Crispytoo]

Today I was out for a bit and encountered more "hot rocks". It was a different park than previously. I was once again using my 5" stealth coil. I tried knocking my sensitivity down to 12 (from 21) but I still was getting that sweet silver signal from these pesky rocks. Than I did something that I normally don't do. I put the SE into "auto" sensitivity. It ignored the rocks. I was also able to kick it back up to 21. Now I know that this masks out some of the good but faint targets but it seemed to work. What I did then was to run without the auto until I got a good upper right signal and than switched auto back on momentarily to see if the target disappeared. It worked.

I hope this helps some of you with your "hot rock" challenges.

Crispytoo

 

[Yooper]

Thank you for the input. I may get to try this out on Saturday if the weather is decent.

 

[Chris(SoCenWI)]

Yooper,

When you burn coal you get left over unburned stuff called clinkers. This can be metallic impurities that melt out of the coal, or stuff that just doesn't burn. And detecting over this stuff can cause your detector to go crazy, lots of iron hits but also way upper right hits like hot rocks.

I've found many of the old sidewalks I detect when torn up have a layer of clinkers under the cement. Guess they used this instead of pea gravel or limestone in the old days. Pretty hard to get through this stuff no matter what you do. Turning down sens may help on the shallower stuff.

Chris

 

[B Spa]

Yooper,
Here is a site I found today; the info might be of some help. http://metaldetectingworld.com/index.shtml on the right side you will see a list of subjects. Go to my programs for Explorer SE and Explorer 11, hot rocks are covered on page 3. A simple edit and save should be an easy solution.
good luck, mpk