VLF and hot rocks?

[TravyLeigh]

Hey all. So I'm a MXT and GMT user (wanting to learn my GMT better) and I was curious how you folks deal with and better recognize hot rocks?

An area I'm wanting to work is COVERED in hot rocks, and drives the detector and I both nuts, moreso with the sensitivity up. How can I pick out which is a hot rock signal compared to a good one?

Found a piece of bedrock that sounded off with low % of iron, strong signal, then it said high iron, then low again. Pyrite perhaps?

Any tips would be appreciated


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[goldchaser3]

My best luck and best prospecting was done by ground balancing on one of the hot rocks. Theoretically it takes a little off the depth, but since you can turn up the gain a little higher plus save yourself headaches and digging up a bunch of hot rocks - well worth it in my opinion.

 

[GreyGhost]

If you're using a VLF detector the best advice I've read is to just learn the sound of hot rocks. They can drive you crazy.
Get to know your hunting grounds as best as you can and just learn the sound of the rocks vs. the sound of gold nuggets. Gold nuggets will almost always put off a MELLOW signal. They're a natural metal and sometimes have quartz attached and other host rocks and are sometimes porous. They aren't always solid, refined metal like an iron nail or lead slug.
Otherwise get a PI detector. Used Minelabs can be purchased pretty cheap off eBay. Once ground balanced, they will cruise right through most hot rocks except for the big black softball sized ones and up.

 

[meMiner]

If the hot rocks are on the surface, they usually can be identified by sight and kicked aside. They are normally the same colour in a particular area. I hate them, so I got a PI so the quantity detected was less.

 

[Goldwasher]

If you balance to hot rock aren't you un ground balanced?

 

[Featherdfishead]

Good advise above, Ground balance on the hot rocks and learn there sound. As GG said gold is usually a mellow sound also hot rocks to my hearing have more of a buzz or boing sound than a piercing tone. Hot rocks on surface can be kicked out of the way and identified by sight once you spend alittle time in the location. If the hot rocks are underground you'll get a loud response when lowering or raising your coil over them, If you lift your coil higher the hot rock sound will drop off quicker than a target and also produces a boing type noise when you drop the coil back down on the ground. In many areas hot rocks can be dealt with easily with these methods but you may find that hours and hours of listening the the ground noise gets old and then you'll need and want a PI machine. Many pounds of gold have been found with both your machines so learning the ground noise is the key. The guy that turned me on to detecting always told me to learn the ground noise and then when you hit a good target you'll know it.
Good Luck

 

[azblackbird]

I also use a GMT and I run it wide open. I detect in heavily mineralized soils with hot and cold rocks. As PlacerGold said, most can be kicked off the surface. Those that can't be kicked or scrapped, you'll learn to recognize the tone and how they fade when hitting them from different angles. Every now and then I still get fooled and will dig one up. Same goes for bullets and other junk. That's just all a part of detecting.

 

[Featherdfishead]

Goldwasher - No your not unground balanced - your ground balanced to a different degree. The hot rocks sound as they do because they are vastly differnt from the ground you ground balanced on. There are actually cold and hot rocks one above your ground balance phase and one group below. Anything that is above or below your ground balance phase will cause a response.

 

[Hoser John]

ALWAYS test with a small nugget under 1/2 gram glued to a poker chip to not lose proper GB. All detectors react to these procedures differently and what works on a whites may not on a Tesoro or GB2. Use that chip each hour to check gb,batteries,electrical interference,microwaves,huge base stations etc. will effect your unit . Ground conditions change constantly also so re gb a lot for insurance-John

 

[TheHunterGT]

Yeah you def gotta GB to hot rocks when searching for them nuggets.

With my Gold Stinger if I hit something in All-Metal mode I can just flip a switch to TR Disc and hot rocks will disappear.

I have hit a pretty iron infested part of the Arkansas River and had to raise the discrim knob to about 3-4. The rocks were rusty red it was so bad so I had little choice in the matter.

It worked well.....tested my wife's wedding ring 3 inches down and it hit hard. Placed a red iron infested rock under the coil and it was a VERY broken tone that was basically nil.

Did not find any gold that day...but I was confident that if it was there it would have been in my pocket.

 

[Goldwasher]

Goldwasher - No your not unground balanced - your ground balanced to a different degree. The hot rocks sound as they do because they are vastly differnt from the ground you ground balanced on. There are actually cold and hot rocks one above your ground balance phase and one group below. Anything that is above or below your ground balance phase will cause a response.

I prefer your advice on learning the sounds of the positive and negative (Hot/Cold)rocks and mineralization rather then tuning to it.I'f your properly g.b. and hit a rock that is so off and not obvious until dug...why would the solution be to ground balance to that hot rock? In cobble stacks and hand stacks if those rocks are way off then yes balance to those. If the matrix over bedrock gets hot tune to it. With a sensitive machine a crack in exposed bedrock sounds hot like a target and you can tune to it ,but, then you go back to bedrock and the phase is off again. It is a constand dance....I guess my point as I ground balance I don't hot rock balance. If that makes any sense.

 

[TheHunterGT]

I prefer your advice on learning the sounds of the positive and negative (Hot/Cold)rocks and mineralization rather then tuning to it.I'f your properly g.b. and hit a rock that is so off and not obvious until dug...why would the solution be to ground balance to that hot rock? In cobble stacks and hand stacks if those rocks are way off then yes balance to those. If the matrix over bedrock gets hot tune to it. With a sensitive machine a crack in exposed bedrock sounds hot like a target and you can tune to it ,but, then you go back to bedrock and the phase is off again. It is a constant dance....I guess my point as I ground balance I don't hot rock balance. If that makes any sense.

Some parts of Colorado are so infested with iron that every 5th rock is stained red with rust. Of course that makes visual discrimination easy....not so much for the detector however.

I absolutely have to GB to a hot rock as they litter my gold bearing areas so densely. Even if I tried to miss one and get a neutral GB...I probably could not. It is impossible to swing left to right without hitting 3-4 of them. If it was not for the TR Disc switch and the ability to GB to a hot rock in All Metal mode....I'd be one frustrated prospector since All-Metal hits the same on iron as gold....no tone break up. Only by switching to TR Disc can I figure out what it hot or real by listening. Honestly...I just can't hit the switch that often. I'm afraid it would wear out...my thumb that is lol.

Canceling out the hot rocks by GBing to them is my only option until I find better ground that has more quartz/granite and less iron ore. Unfortunately iron and gold are best pals around here.

If balanced to a hot rock and I get a big hit....I know it is either gold...or a super dense hot rock (most likely cause since gold is rare and iron is common). Then I switch over to TR to see if I want to dig or not.

 

[J0hnct78]

Hello,
If there are any Gmt users within Oregon I would like to tag along.

 

[605dano]

I've had both detectors in the past. With the MXT it helps to to use hypersat. Start at 3 and work down. Manual ground balance also helps. Having said that I've been in places where the MXT was unusable. The GMT is better in hot rocks. Just keep coming down on gain and going up on sat until you get somewhere you live with. Much prefer the MXT over the GMT. Wish I hadn't sold it. Good luck.

 

[TravyLeigh]

How do you manually ground balance the GMT? I mostly use it in auto, but when I use manual, I generally just press ground grab


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[J0hnct78]

Put it in manual mode then use the plus and minus buttons

 

[TravyLeigh]

No "pumping" required? What's the positive side of manual?


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[J0hnct78]

Well you still pump... If you haven't watched the whites training videos they are really good at explaining how to manually ground balance. As for the pros, some people think you can get more sensitivity by running a little hot... Which maybe true. I just begun so I really can't confirm

 

[Hard Prospector]

In bad ground, using a 4x6 Shooter instead of the standard 6x10 Goldmaster coil helps with staying balanced. If you run in tracking and get a good signal on the initial pass of the loop, don't keep swinging over the spot(trying to pinpoint) 'cause the machine will track it out. Instead, keep a constant swing to the sides and near target area then go over it. Increasing V SAT and decreasing gain is also key in nasty ground (as 65dano said) Good luck!

 

[TravyLeigh]

Will do on the swing thing and decrease gain/increase sat, I'll go play in sand with little bits of lead pellets broken up to test it out, only get to prospect on weekends thank you! Detected some yesterday, didn't find anything. So I sluiced and found a few things. Maybe a total of .25 gram. Meh, better than a kick in the testes!


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