What is this stuff i keep finding.

[mrmayhem]

Hope this isn't the wrong forum, but I have a question of the general sort.

This has happened to me twice so far, ill be be swinging in a new area and ill get a great reading 80-90 and when I dig, its allways very rocky gravely dirt. Which tells me its fill and an area that has been landscaped with earth movers. When I get to target depth my pinpointer starts going nuts and I find pieces of this black rock. It looks like lava or something. Where does it come from? is it metal slag? its very frustrating and has ruined a few hunts. I do properly ground balance, but I guess I need to learn more about my machine.

Do yall avoid areas with this "fill"? have you found this black slag rocks?

 

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[firemac]

Have any pictures?

 

[Isaac]

Hot rocks, yes I'd avoid that area.

 

[mrmayhem]

no pictures , but that's all I need to hear. i will avoid this type of area

 

[austin]

Find an old geiger counter or a radiation detector(available at Science supply houses)fairly cheap, Test the deposit and you'll know instantly whether to run or not. If you know a science teacher, borrow a Roentgen meter. School science room(high school) should have several.

 

[cactusman]

If you're properly ground balanced your detector should be able to handle the area. Add in some iron discrimination and you should knock out the response from the hot rocks. It sounds like (from your description) that the rocks are basalt, a type of volcanic rock that has a higher than average iron content -- test some of the pieces with a magnet, as some basalt will stick to a rare earth magnet, depending upon the amount of iron it contains.

One more thing to clarify in case someone is confused on the subject... "Hot rocks" is just a term coined for rocks that are "out of place" with the soil around them, and typically they have a higher iron content that the surrounding soil. Some types of soil (like clay) can be like this as well, making ground balancing and searching difficult. It's not to be confused with something that is radioactive, or otherwise harmful. They (hot rocks) are just annoying when detecting, but they aren't anything you can't deal with once you have some experience.

 

[against the wind]

Yep, sounds like an area that has a deposit of hot rocks.
Welcome to Tnet

 

[Mrdigz]

Gotta love a good hot rock spot!!!