AZO's Detecting Tips

Bob Dansie

I often get calls and e-mails from beginners who despite many trips to known gold areas just can't find any nuggets. They are going to patches where others find gold but still come back empty handed. I almost always know what I will find when they join me for a lesson. Almost without exception I see a wild, fast, uncontrolled coil swing. This will work just fine for large shallow targets; bullets, nails and the like respond just fine to this approach. So will a large shallow nugget. But how many of these are left on a really hammered patch? How do some operators find gold day after day on hammered patches? The answer: A slow, calm, plodding approach!

With a PI detector a weak, tiny, or deep target will not be heard with the fast swing. It's that simple. Rapid, jerky movements can also cause false signals. A very small nugget or a deeply buried one will respond far more clearly if the coil is being moved VERY slowly. Being a motion detector it has to be moving a little. In fact a target will fade away rapidly if the coil comes to a total stop over it. But just like with medications, more isn't better. I can make a weak signal totally disappear just by increasing my swing speed. Increasing swing speed can also increase the signal response on hot rocks, hot ground, and black sand. I can make the signal response virtually disappear on these unwanted “targets” by drastically slowing my swing speed. On the other hand, a good metal target will increase in signal response!

This is where the slow swing comes into play on a hammered patch. You are looking for that nugget that got missed by dozens of others who were there before you. The chances of this happening increase if the ground has some difficult factors like those mentioned above. By decreasing the unwanted signals and increasing the wanted signals you will hear that faint signal that got passed up. The real pros that use this method often don't even actually swing the detector. The coil is placed on the ground or very close to it, and poked and guided around obstacles. Taken to extremes like this, virtually nothing is missed and I use it often on the once very rich patches that have really been hit hard. It might not pay huge financial rewards but if it gets you that first nugget it can be a real eye opener.

Finding the first nugget no matter how small is the most important milestone for anyone who has recently gotten involved with the hobby. Going home with a nugget in your pocket will make you love your detector and the dear wife/husband may quit calling you a fool.

These photos are of some nuggets I found over the last few days using the “creep-and-crawl” method on some of the Bradshaw’s most pounded patches. The 3 smallest combined wouldn't even register on my digital scales which take 1/10 gram to activate!

Now we'll get to the exceptions. When hunting for new virgin patches you simply can't cover enough country scrubbing your coil on the ground. In desert situations a new patch will usually have some nuggets sitting very close to the surface. It will often have some large nuggets in the 1/4 ounce range or bigger. There will be some “sitting ducks”. The sitting ducks are what you are looking for while patch hunting. These will respond well with a ground covering swing. A few years ago I stumbled on to one of these. It wasn't really a patch in the normal sense but a vast area of gullies with nuggets in almost every one of them. One gully in the area had been extensively worked by the old-timers, but the rest of them had been totally ignored. I suspect that this rich gully was so rich that they never bothered to dry-wash the surrounding gullies that were not so rich. Since these poorer gullies weren't messed with the trash was almost nonexistent. Once I realized what the situation was, I hit these surrounding gullies very quickly swinging only for the sitting ducks because I knew that it was only a matter of time before someone else stumbled onto the area.

By taking the sitting ducks I knew that someone exploring at a searching pace would be likely to pass through the area empty handed. I could then return later and pick up the smaller and deeper ones at my leisure. It worked very well and I still return to the area and get nuggets on a regular basis despite the fact that there are now club claims in the area. As far as I can tell, no one has stumbled onto it. This now has become a pounded patch and the low and slow approach is the only way to pick any nuggets out of it. The few nuggets that remain are either deep or very small and I really have to work for them.

The beginner with no idea about geology or indicators or how to recognize tell tale signs of old-timer activity has a slim chance of finding a new patch with only blind luck working for him/her. It does happen but it's akin to hitting the lottery. They are far more likely to find gold by carefully working some known patches. Once they have seen several of these patches then he/she will have a good idea of what to look for and with a few nuggets in the poke will have the confidence to start exploring for a new patch of their own. Those who really pay attention to what productive ground looks like and are really observant of their surroundings catch on fast. Those with their head in the clouds, wandering around day dreaming, or worrying about problems at work or home will have a tough time.

Lightening the Load: Weight and Leverage Modifications

R.K. Patrick

I had a real hobby threatening problem with my shoulder after an over zealous all day outing, swinging one of the heavier coils made for the Minelab detectors. Actually, I had to learn how to detect with my other arm after that day. It took months before I was able to even tuck in my shirt normally. Really enjoy this sport, so I needed to do something.

Started out thinking that the over all weight was the problem. So like any machinist I started cutting weight off the detector. After cutting as much material off of every part I could with out destroying its integrity, I removed every piece of metal between the coil and the green button on my GP3500, and replaced it with plastic, except the coil wire. In the process coil wire clips on the top corners of the control box where removed. To show how serious I was I even poked lightening holes in the control box feet that may have saved 1/10 of a gram. I even purchased a fiberglass upper shaft.

At that point I had not accomplished much; all told the weight was reduced by a shade under a 1/2 lb. While reassembling the detector umpteen times I noticed that with the wire clips removed I could slide the control box closer to or farther from the coil. That’s when the lights came on. It was not the over all weight that broke me; it was the leveraged weight of that heavy coil. Balance is what was needed. From that point on it was just a matter of transferring weight. Using the bottom of the handle grip as the pivot or balancing point every gram possible was transferred to the control box side of the handle. That lead to a little fiberglass attachment tube I made that allows the control box to be slid away from the coil in seconds. This adjustment allows one to achieve the preferred balance weight, after switching to a different weight coil without changing the over all weight of the detector. I made a test fixture and purchased a digital scale to gather weight information on different coils and configuration. That turned out to be just a lot of technical paper work. Bottom line it does what it is supposed to do; it lightens load!

Posted below are a few pictures of the end results of my efforts. Still have a few minor ideas to try, but this will give you an idea where I’m headed. Some of the modifications are very subtle and you may need to look hard.  I found the total weight is important, but not nearly as important as balanced weight. Using only an attachment such as this would help in leveraged weight on a stock unit. This modification allows you to stay in the field detecting longer with less fatigue. Sounds like I’m selling something doesn’t it? I’m not.

Things brought to light along the way. You can make a fully dressed GP3500 weigh less than 6 pounds. For every pound added to the coil it increases the leveraged weight by approximately 4 pounds. It does make a difference how far away the handle is separated from the armrest. The farther the two are away from each other, the lighter a coil will seem. It does make a difference how close the coil is to the handle, the closer the lighter the coil will seem. Stock Velco ties are 4 times heavier that a small zip tie cut to size. Normal electrical tape weighs 1/10 gram per inch. There are plastic replacement screws for every steel screw on the detector. The list goes on and on. Is this information for everyone? Nah! It’s only for those that can get some good out of it. Hope it helps someone - it did me! 

Chasing Gold on Bedrock

Chris Gholson 

Bedrock is essentially an exposed portion of the Earth’s crust and comes in all sorts of varieties. Sometimes it is schist, other time granite or volcanic, and sometimes it is not even a true rock, but rather a false bottom like caliche. Whatever it may be, it is a good place to search with a detector because the gold will almost always be within a machines’ depth range. Hunting bedrock requires different techniques than regular dirt because there are many possible hiding places for a nugget. Even after the signal is pinpointed a prospector cannot be 100% certain where it is lodged within a crack. If the bedrock is highly weathered it will typically break apart easy. If it is composed of a harder rock it can be a chore.

Here are two items I always bring along when targeting bedrock: 1) a strong rare earth magnet, and 2) a flathead screwdriver. A powerful magnet is brilliant for quickly removing ferrous junk like wire fragments, boot tacks and bits of decomposed cans. It saves a lot of precious detecting time and is easy to use. After you have most of the sand and gravel out of a crack, simply rub the magnet into the hole. I attach mine to the end of my pick, so it also works as I’m digging. Just be careful if you carry your pick on your side and your wallet in a back pocket. I’ve wiped out more than one credit card this way! The trustee flathead is another tool I’ve put to good use. It is much easier to maneuver in tight bedrock cracks than a pick head, plus you can take your time making sure a nugget does not get damaged. Don’t use an expensive one, instead go for a “junker” in your toolbox or pick up a cheapo from the hardware store. I have lost many of them over the years after digging up a nugget and in my excitement walking away. Now I leave it stuck to the magnet on my pick (see picture). Another inexpensive device you can use while bedrock hunting is a straw. That’s right – a straw! Grab a few from McDonalds the next time you swing in for a burger. They are great for blowing out sand filled cracks. It might seem goofy, but it works!

Most of the gold I’ve pulled from exposed bedrock has been small (2 grams and under), but it is still one of my favorite places to detect. Sure chances of finding a big lump on bedrock are slim; even so I get a real charge from picking tiny bits in between the folds of rock in a gully. If anyone else has tips along these lines they’d like to share please feel free to add. Good luck out there!

Building a Coil Cable Stabilizer

Bob Dansie

Ever since I first got interested in beeping for gold I noticed that I often would get a false signal when the coil wire was bumped or moved near the connector going into the control box. This problem continued even with the PIs and seems to get worse as the detector and coil get older. I think that this is because the constant movement however small eventually damages the wire and the connector. I have had several Emails asking me how this problem could be eliminated. When I recently had several coil connectors get progressively touchier, I decided to put my mind to work on it. Digging around in my organizer boxes in my workshop I came up with some parts that looked like could be made to work. Once I had it all together I felt sure that it would go a long way toward eliminating the problem. This first photo shows the parts I used which are available at any hardware store and a lot of you might have them in your shop already.

This now will clamp on the shaft. If it doesn't clamp on firmly you may have to squeeze the 3/4" EMT clamp with a pair of pliers and try it again. Here it is in place and the coil cable will slip into the Co-ax clamp.

I decided to go one step further and added another of the nylon clamps to the bottom of the handle bracket. This was done by removing the forward tightening bolt, sliding the clamp into the slot and then replacing the bolt. Another photo.

The last photo shows the finished product from the bottom.

By leaving the nylon clamps open coil changes can still be easily done. If you look at the third photo you will see that the cord now has a straight shot into the control box plug with no side pressure and will be very difficult to move out of position. This may not seem like a real big deal to some people but I don't like hearing false signals and having to retighten my coil connector all the time. I am sure that it will prolong the life of the wire and connector and without the falsing or possible temporary loss of a good connection might just mean more nuggets in my poke. For a cost of about 50 cents and a few minutes of my time , I think it was well worth doing.---Bob

Ground Balancing the Minelab GP Detectors

Bob Dansie

I have run into quite a few GP owners who are still a little confused about the importance of a perfect ground balance. I have even run into a few who think that hitting the tune button is ground balancing the detector. Most successful GP operators choose to run in fixed and there are good reasons for that. The first thing I do when I start hunting is to get away from the car and check the ground for trash targets. This is very important because any metal target in range of the coil will affect the ground balance. Place your finger on the Track/ fixed switch. Starting in the fixed mode start moving the coil up and down rapidly. (only an inch or 2). While doing this, switch to track while continuing to pump the coil up and down. After a few up and down strokes the threshold will smooth out to where you get no variation in tone between the up stroke and the down stroke. Switch immediately back to fixed at this point. Once you get the hang of it it only takes a second or two. I do it one more time and at this point I am sure that the detector is perfectly balanced to the ground. I am then ready to hunt. As you move from one area to another you may notice your threshold wandering a little. The detector is telling you that you have moved to an area with different mineralization. Just go through the ground balance procedure again. I do this as I am walking and swinging and don't even miss a step. In most areas you will seldom have to do this. Even if my detector sounds like it is properly ground balanced, I periodically re-ground balance. If your detector is out of ground balance you will miss targets!

Some folks choose to run in tracking which will work fine in flat clear areas. The problem with running in tracking is that if you have to raise your coil several inches off the ground to clear a rock or other obstruction the tracking feature will automatically try to track to the air and when returned to the search height will be confused for as many as ten steps or so. You are out of balance! To speed up the re-tracking process switch to fixed then back to track. This forces it to instantly re-ground balance. If you are running in tracking and get a target you set the detector on the ground while digging usually. This again throws it out of balance. Now when you check your hole and pile you lift it off the ground several inches. It is really confused now and if the target is tiny you may lose it completely. My advice to those who choose to run in track is to move the coil a foot or so to the side of the target and reground balance then leave in the fixed mode throughout the retrieval process. You won't lose those tiny targets. I often find small nuggets beside fresh dig holes and I am sure that this explains why they were left behind. Running in tracking can help smooth out noisy ground and cut down on hot rock noise. In tracking a suspected hot rock can be checked by swinging over it several times listening for a rapidly diminishing signal. If the signal remains strong and doesn't diminish after 3or 4 swings start digging. Most ironstone hot rocks can be eliminated in this way but some of the basalt (lava) can't. Just remember that if you are lifting the coil off the ground frequently, then running in tracking mode can cost you nuggets unless you switch to fixed then back to track after each time it is raised more than a few inches. A consistent coil height becomes much more important while running in tracking mode.

Large Coil Setup: Swingarm Modifications

STAN WARD

Here's a tip for setting up your GP/SD for using a large coil. I've found that even using a bungee sometimes doesn't help much when swinging a larger coil all day, so I recently purchased a swing-arm setup. The first thing I noticed when I pulled it out of the package, was that the lower part that attaches 6-8 inches above the coil was held together with two METAL bolts/nuts! Fortunately, whoever designed this unit made the holes the exact same size as the nylon bolts that hold your coil on the shaft. A few minor mods later and I now have a unit that is usable and doesn't contain any metal near the coil.

First, I have to say that I replaced the original shaft that came with my GP Extreme with an extra long fully fiberglass one, so you may notice that it is a little different then your stock shaft. It's still close enough that these mods should work on a stock shaft.

I have 10 coils that I use in the field and have 6 lower shafts that I use and two of these are the heavy duty, extra length shafts. I used one of these to mount my swing arm on, and this way I can leave it set up and just put the shaft/coil on my unit just like any other lower shaft.

The first thing I did was to remove the metal bolts from the swing-arm. The one that attaches to the arm itself is a small one, but there is a plastic insert that is easily removed, and the remaining hole is the same size as the nylon bolts for your coil. This first picture shows the insert about halfway out along with the original metal bolt.

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This second picture shows the end that attaches to the shaft. It has a molded insert that fits the metal bolt and also is the exact same size as the head of a nylon bolt. The inner diameter of the attachment was slightly larger then my shaft diameter, so I cut the end off of a 12 pack of beer and used it as a spacer wrapped around the shaft.

This third picture is after assembly and shows how the retaining clip can be used to hold the shaft & swingarm together for storage.

And this last picture shows the final assembly at the upper end of the shaft. The retaining clip snaps onto the shaft and holds the swingarm handle in place when not in use.