Tuesday, December 14, 2010

Metal Detecting

 Of course any method that keeps you out of the water is a good winter method. A few months ago I wrote several posts on metal detecting. There is a great deal of interest in this subject as you have noticed if you read TreasureNet so I thought I would repost for those who missed it. Everyone has strong opinions on the subject, and this post is in no way meant to discourage anyone from experimenting and discovering for themselves. I have edited and revised my remarks so that I could cover the subject in this one post. Hope you enjoy.
Just a few notes on metal detectors. I started working with them about 15 years ago, and I'm still learning. I've seen a lot of people plunk down a grand or more and their detector ends up gathering dust in the hall closet. Folks, it's a long term commitment when you buy one. I've got three, and it depends on where I'm going and what I'm going to do when I get there as to which one I take (they're all gold machines - Gold Bug w/ 3" coil, Garrett Gold Stinger and Minelab XT 17,000). I am always selling and trading machines to see which I like the best, and there are some new ones I want to try. I use the Gold Bug the most because I usually end up working the crevices. The point I want to stress is that they are not a miracle tool that is going to make you rich! The problems are:
1. You've got to be in a nugget area (that ain't easy).
2. Nuggets have to be close enough to the surface that the surrounding mineralization will allow you to hear their signal ( that's near impossible!)
3. You have to have enough experience with the different sounds to know what you're hearing (that takes years of practice).

I will limit my comments to gold machines. If you are interested in coin or relic hunting and have that kind of machine, this will not work for you.
If you are interested in finding gold, sorry, you have to have a gold machine. There are numerous gold machines on the market, and you know what? It doesn't really matter which one you buy. The reason is that you are probably not going to MASTER the one you own and you have to master it to do any good at all - unless you just get lucky. So instead of talking about specific machines, I'm going to talk about theory, specifics and techniques.
Theory - After a machine is properly balanced (check your instructions), it will make either a positive or negative sound when it is moved over varying degrees of mineralization in the ground you are hunting. As I said before, the problem is that most gold bearing ground has wide swings in positive and negative sounds. Not only are you going to be dealing with scrap iron from previous gold rushes, but the next biggest problem is "hot rocks". "HR" " are rocks that have a higher iron content than the surrounding area (they can give off either positive or negative sounds). I'll get into ways of dealing with iron and "HR " in my next post.
Specifics - Discrimination, Ground Balance, Target ID, Sensitivity, Volume and threshold and Mode. Once you've got the concept of these under your belt, it's a matter of practice, practice, practice.
DISCRIMINATION: In hunting for gold this one is easy. Don't use ANY and dig every target until you are comfortable with being able to identify targets without digging (that takes at least a decade). Now if you've talked to a super salesman who says this machine can discriminate gold - and you believed him and bought the thing, use it on its' lowest setting (that means iron only). Anything more and I guarantee you lose gold.
GROUND BALANCE: (read your instructions) Every machine is balanced with a little different method. "GB" is where your machine is electronically balanced with the mineralization in the ground you are hunting. Generally when you move your coil up and down from surface to 2 feet there should be no difference in the sound of the threshold of the machine. Now it is balanced. It is important to check your "GB" every few minutes because ground mineralization changes. Also remember to check it before you dig a target. 50% of your digging can be eliminated if you do this because many sounds are false sounds based upon improper balance of the machine. The automatic ground balancing machines that are now on the market are good, but I don't think you should let that be the deciding factor in the purchase of you machine.
TARGET ID: The idea with the nugget on a poker chip is a good one for practicing target ID, but don't stop there. Get a small piece of brass, aluminum, iron, and various hot rocks. Now spread them out and study the various sounds. Bury them at various depths and mix them with hot rocks, and try it again. If you have a machine that "identifies" the target- throw it away. Remember there's only one target - GOLD. Now as for the other target signals you get - dig them all. If you only find one OZ nugget out of 1000 digs, would it be worth it? More on target ID later.
SENSITIVITY: This is an easy one also. On most machines you can operate at 3/4 to full sensitivity depending upon ground mineralization. Always operate at Max sensitivity that you can with out causing "fuzzy " interference to the sounds you receive. Now I'm going to say something you've never heard before - I seldom use head phones unless I am near a river or some other outside noise or unless I want to work quietly. True, you may be able to hear those faint sounds better with headphones, but they are hot to wear, block other sounds you may want to hear (like a charging bear), and if you can't ID the loud sounds - you certainly won't be able to ID the faint sounds.
VOLUME AND THRESHOLD: If you have a machine that you can adjust the volume and threshold, turn the V to max and the TH to minimum. You want to be able to just hear a faint hum of the threshold.
MODE: Various machines have various modes of operation. In searching for gold we mainly use an "all metal" mode. A discrimination mode can be used at its' lowest setting after you have experimented and satisfied yourself that you won't lose your targets. (My preference is to search in all metal, and use discrimination to ID a target). But remember, I've been at it awhile.
TECHNIQUES: Here in AZ there is every kind of gold country you could think of. From Pine tree forests with year round streams to 120 degree desert with only prickly pear cactus, and dry creek beds. So, I've tried every technique in the book. One thing holds true for almost every location - Your biggest nuggets are going to be close to bedrock or in bedrock crevices. And since they haven't made a machine that will detect flakes through other mineralization yet - YOU'VE GOT TO GET TO BEDROCK to find the best gold. Now if you're in an area where the creek has been worked fairly heavy, you can expect that all exposed bedrock has been searched - right? Well, not totally. You see most nugget hunters only work the easiest ground. I always carry a small pry bar and metal chisels because most exposed bedrock has crevices that will split wide open with a little smack, and most everybody else will walk right over the best crevices because they don't want to "bend over", much less move any boulders or open any crevices. My best advice to a beginner is to do your homework and go to an area where the very best nuggets have been found (they never get them all). Don't search any dirt or gravel bar with more than a foot of overburden. Speaking of overburden, that brings me to my second TECH: If you have a gravel bar or bench that you want to work, don't just run the detector over the top and move on. Detect the top then take your shovel or rake and remove the top four or five inches of dirt and go over it again. Keep doing this until you get to bedrock and then look for any crevices in the bedrock that should be split. Now let's talk about iron, and using all metal machines (no discrimination). You should carry the strongest magnet you can find. This will save you hours on you knees. Remember the first thing to do when you get a signal is re-ground balance your machine. If you have a true target signal, the second thing to do is pinpoint the target, turn over the first few inches of dirt with your pick or the toe of your boot and run the magnet through the dirt. How To: I place my magnet in a 6 " piece of plastic pipe with a cap on both ends. That way the black sands and junk don't get on the magnet. Just jerk the mag to the other end of the pipe and the stuff falls off. Hint: I wear a metal cleat on the toe of my boot for that first kick at a target. ( If you can move it with your toe, you know it's right near the surface). After several attempts with the mag, if you don't pick out the target try to retrieve it as if it were gold. (You know - hand to hand to hand. I don't like plastic scoops and cups).
I want to close this post with this lesson: Get rid of the other noises by shoveling down to an inch or two of bedrock and you'll be able to identify the sound of a nugget and that's where the best gold is anyway. If you'll throw a 22 bullet down there and check it, you'll see what I mean. There isn't much if any difference between a .22 bullet and a nugget about the same size. If there are specific questions I can help you with, please don't hesitate to Email me direct. P.S. I won't recommend any machine over another. Good luck.......
RF Courtesy of MininGold.com

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2 comments:

thanks for information

http://dfminerals.blogspot.com/

hanks the use of metal detectors which is a lot of fun and the search for the unknown, they are a good hobby you may be due some money when you find some old coins, or gold, or jewelry, it's really fun

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