TGSL and Hot rocks!

[yatahaze323]

Hey everyone,

I've been finding hot rocks where I am, not alot of them but enough where it's annoying. I'm using a official 9x8 tesoro coil and the hot rocks I'm finding sound like good targets too.

Has anyone else experienced this with their TGSL?

Any tricks to identify them before digging?

Thanks!

[waltr]

From what I read about detecting in the Australian gold fields, hot rocks are always an issues with almost all detectors.

Are the hot rock you find attracted to a magnet?
Are they magnetized, cause a compass to deflect??

I am guessing you are running the TGSL in Disc mode not All Metal mode.

[yatahaze323]

Hi waltr.

I haven't tested the hot rocks with a magnet or compass. I live up in New England USA so the ground isn't mineralized so I ground balance and when I find a hot rock I've been ground balancing to the hot rock. This seems to help with the smaller hot rocks but I still hit the really large ones. Also I know I'm loosing depth by ground balancing to the hot rock which I'd like to avoid if possible.

Also you are correct, I'm running the TGSL in Disc mode.

[waltr]

I am interested in magnetic properties of the hot rocks.

I am currently building a TGSL so not experience in the field yet.
I having been using a PI detector, which has no iron elimination, and I have found pieces of coal and sometimes what seems to be iron slag that were easily detected. These are the only 'hot rocks' I've run across.

Iron slag has been used for roads, concrete and fill. Maybe these are what you are finding.
These are not solid iron but are a matrix of iron and other non-conductive particles. So probably not being rejected.

[Nandor]

Hi Yatahaze

Could you please measure the phase shift of a hot rock with scope? Im curious about it, maybe you could Disc it out.

[green]

I am interested in magnetic properties of the hot rocks.

I am currently building a TGSL so not experience in the field yet.
I having been using a PI detector, which has no iron elimination, and I have found pieces of coal and sometimes what seems to be iron slag that were easily detected. These are the only 'hot rocks' I've run across.

Iron slag has been used for roads, concrete and fill. Maybe these are what you are finding.
These are not solid iron but are a matrix of iron and other non-conductive particles. So probably not being rejected.

Some measurements made with a PI I posted awhile back. Hot rocks from California. Looks like the large rock is very close to ground, small rock decays faster. Data was taken awhile back, maybe could get better data now. Think the steeper slope at less than 7us is caused by the coil current still decaying?

[dbanner]

Sometimes when the signal is non repeatable( it only beeps on swinging to one side and is silent on the backswing), then you suspect maybe a hot rock of some type. If you are in area where there are lots of mineral rocks/pebbles near to the surface, you are doomed. Look for another patch of ground or area for searching.

[yatahaze323]

The hot rocks I'm finding are usually the size of my fist or larger, they aren't everywhere but I'm finding them often enough where its I'm digging them cause they give a really nice signal.

I've tried to max out the Disc and I was still able to detect them. I'll have to test the repeatability of the signal, I know some of them weren't repeatable and I could only hear them in one direction of the swing.

I'll have to collect a few and check them out.

[yatahaze323]

I was messing around with the TGSL and the hot rocks and I had a thought. I'm wondering if I change the TGSLs operating frequency to 12kHz if that might solve my hot rock issue?

[dbanner]

I was messing around with the TGSL and the hot rocks and I had a thought. I'm wondering if I change the TGSLs operating frequency to 12kHz if that might solve my hot rock issue?

Hot rocks is notch issue.