Dealing with hot rocks

calgeologist

Jr. Member
Oct 31, 2011
50
46
Austin, TX and Motherlode
Primary Interest:
Prospecting
So I have recently purchased a gmt as some of you may know already.

I was watching the whites instructional video where they are manually ground balancing out a hot rock. Them he puts a piece of gold on the rock and says see it still picks it up. My question is if he had ground balanced the hot rock with the gold on it would he have lost the signal as I think he would have?

Thanks for the replies
 

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63bkpkr

Silver Member
Aug 9, 2007
4,069
4,618
Southern California
Detector(s) used
XLT, GMT, 6000D Coinmaster
Primary Interest:
All Treasure Hunting
GMT Ground Balancing Hot Rock or Gold

cal,
I do not think so but there is still a question mark in my comment. With my GMT I've detected over hot ground and have gotten some garbage signal along with a possible hint of a good signal and then holding the coil over the target area I've depressed the Grab button, adjusting the ground balance to null out the hot ground, and bingo the gold target signal came right out and the iron graph showed gold as a high possibility. There was gold there as well once I moved the 'overburden'. This sort of answers your question.................63bkpkr

191_9174.JPG These pieces of gold and lead shot were found via the above method
 

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goldchaser3

Jr. Member
Jun 21, 2010
67
28
Hi Calgeologist,
I haven't watched the video but don't think the gold will balance out, unless it is extremely small - and then the detector will be really be balancing out the (positive) hot rock and will just be diminishing the response of the gold to such a low level that you cannot hear its response. A ground balance function only has so much "range" that it can null. And it is designed to null mineralized ground, not targets. A positive hot rock acts more like a target, and you can't really ground balance-out targets. (discriminate-out = yes, but GB-out = no, although I don't think the GMT has a discrimination function like the MXT, which I used to own, does.) The only exception being targets that may show up very low on the ID scale, which is where very small gold lives.
From the GMT manual:
"These positive "hot rocks" are almost impossible to tune out" and "We find it best to tune to the majority ofthe ground matrix and learn what a "hot rock"sounds like. " I think this may be the best advice. When they talk about ground balancing-out a hot rock they are referring to negative hot rocks, which I have not encountered here in northern California. And the adjustment for a negative hot rock is the opposite direction of a target, which should actually enhance the response of gold.
That is my understanding, but perhaps some folks with more expertise than I may have more/better insight.



 

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calgeologist

Jr. Member
Oct 31, 2011
50
46
Austin, TX and Motherlode
Primary Interest:
Prospecting
Thanks guys. Thats what I was thinking, just didn't know why he didn't do it in the video. Finished with finals and I am so excited to take my new toy out into the field!!.
 

Hoser John

Gold Member
Mar 22, 2003
5,854
6,721
Redding,Calif.
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problem is when done all other small gold also disappears-apples/oranges-get the bign's or all and play with hotrocks-will NOT ever own one so not my problem-John
 

trinityau

Full Member
Jan 20, 2010
239
797
Redding, Ca
Detector(s) used
Gold Bug Pro, GP 3000 modified
Primary Interest:
Prospecting
Hey guys, when I take someone to get them trained up on a gold detector ( does not matter which unit ) I show them how to balance the unit to the fullest extent. This has to happen to be able to hear the smaller and weak signals. All hot rocks are of a different consistency and give that general boing. The smaller the hot rock the sharper the signal at times but not always, however still a sharp boing. Most people that are better at handling hot rocks are those who are using their units more frequently than other individuals. All I have been hearing so far in this discussion has been the sound of hot rocks. After show and tell with people I take out I prefer to push them in the direction of identifying that gold signal. I will probably get some heat over this next statement... however, if you get your ears right to the unit you are using and do spend time with that unit you will be able to identify the gold. You need to be adept at the far sharper signal gold gives than a hot rock does. There is a difference. To the untrained ear and as I said earlier someone who just goes out for day or so a month then that person may not pick up on the subtle difference between the two. Yes I still get fooled every once in a while but not much. Focus on the gold signal and I think that will help you more than trying to focus on the hot rock.

The other thing any gold detectorist needs to learn is to quickly ID a hot rock. In all gold areas hot rocks are very common. In each area almost all the hot rocks have a similar appearance as far as color and type of consistency. With all the newer units nowadays you will also get a meter reading on hot rocks that helps alot. Try taking different size pieces of gold and similar size hot rocks while out in the field, not in the garage, and properly ground balance your unit and play with them side by side. You will hear a difference and you will see a meter reading that is a bit different between the two also.


In gold areas you will encounter hot rocks. Each situation is different, at some areas hot rocks are on the surface, some areas harbour a few sub surface. There are so many scenarios with hot rocks that I cannot go over them all here. The point being is that a person detecting for gold needs to be able to pick up on the identification of hot rocks in their local area, scenario. At some point you should be able to walk through an area and be able to see hot rocks. Try this and you will be surprised. This is game of familiarity and if you dont think you can overcome the hot rocks then this game may not be for you. Almost all my best finds are in areas loaded with hotrocks. I have come across places where I do not encounter any hot rocks and find gold, but not many of them.


Again, I think if you focus on the sound of gold things will start working better for you. These are just my opinions, TRINITYAU/RAYMILLS
 

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