Question to Eric or Bill about the Goldscan 5 . Distinguishing tin cans from large nuggets with the GS5?

[bakergeol]

OK I admit I have cabin fervor with snow on the ground here in Colorado.
I have been doing some bench testing with the GS5 even with the extreme interference I have in my home.

Normally as the ground is not extreme in my area I run the GS5 in normal PI mode and then switch to GB for metal ID. I normally have the GS5 set at the 3:00 position. Here small low conductor such as gold and Al will produce a high tone. With some exceptions iron will produce a low tone. Larger low conductors and other high conductors will also produce a low tone.

Now instead of the 3:00 GB position I have been placing the GB in the 10:00 position(pulse delay 10). The small low conductors of course produce the high tone(Here I also noticed intermediate copper can give a high tone also). Also as expected large low conductors such as Aluminium pop cans or couplers and larger high conductors such as copper produce the expected low tone. However, all iron regardless of size will produce a high tone at this position. Now is this test invalid because I am not using a soil matrix here but pure air?

I mean it can't be this easy? If I can readily distinguish an AL pop can(low tone) from a an iron tin can(high tone) with depth I can do the same for a large nugget. Switching from PI mode to the 10:00 GB position I can tell an intermediate sized low conductor(one ounce minne ball) as being non ferrous by the greatly reduced signal response. A ferrous object's response would only be slightly reduced coming from the PI mode to the GB mode.

So is this procedure possible in the field or is this just wishful thinking? Hmmm...Well maybe I am not the first person to notice this?

George

 

[Anonymous]

Can you elevate a container of soil above the floor to try out the items? Are you the guy that has the Ferrous Hound hooked up to your GS? How does it work?

 

[bakergeol]

Hi Vlad
Well I am about to leave for work in a field camp in the wilds of Colorado so I will be out of circulation for a while. I see if I can find some thawed mineralized ground upon my return.

Yes I use a Ferrous Hound with my GS5. It works well with some limitations.
As I like to use the GS5 and FH running at the same time with mono coils I have feedback issues or interference to the FH and GS5. Actually this is less of an issue with DD coils as you simply mount the FH sensor on the transmit side of the coil.

Eric's mono coils are so well shielded(open coil) that as long as you keep the sensor more than 1" from the mono coil you will not get interference to the mag. Interference to the GS5 is another story. PI mode about an inch from the coil, however GB mode requires 2 1/2 inches from the mono coil. So if you plan on using the PI mode only you can mount the sensor directly in the center of Eric's 11" coil, however, if you plan on using the GB or a small coil the FH sensor must be mounted at least 2 1/2" to the side of the coil. I have a plastic strip with Velcro so I can change the orientation quickly. Eric just needs to make a 12" or 13" open coil.

Depth-- The FH has decent depth but the GS5 can have greater depth on iron objects. Hot rock 2"x1" =20" whole tin can= 20"
can crushed = 16" rusted iron nail 1 3/4"x1/2"=12 1/2" 1/4"x1" bolt= 11" bottle caps= 5" to 61/2" large paper clip = 4 1/2" quarter size- paper thin rusted steel = 3". Depth of detection with mags like this are dependent on the shape of the iron object. The better the shape(non flat) the deeper the depth. Thin flat steel objects can only be detected at shallow depths.

For gold ring hunting at the beach with the GS5 the FH would not be of great importance as you are mainly just digging the high tones. However, it would help on some new steel bottle caps and heat treated steel which produce high tones. Nugget hunting is a different story.

Sorry so long- Just bored with cabin fever
George

 

[Eric Foster]

Hi George,

There should be no difference in the results you have obtained, whether in air, or in the ground. I tried your settings on a unit I have here and got similar results from iron objects. Also, the responses will be the same, whatever the depth.

If you want to use less GB, so that you can use the control more as a metal discriminator, it may be interesting to try a DD coil. This will inherently give less response to iron minerals, so that you need less ground compensation from the electronics.

Eric.

 

[bakergeol]

This is incredible when you think about it. For nugget hunting in mineralized soil employ a DD coil in PI mode. When you get a hit toggle the GB switch(which is set at the 10:00 position). If you get a low tone or greatly reduced tone- dig as you dealing with a non ferrous object. As small nuggets will produce a high tone similar to iron to see if you have a small nugget less than 1 ounce move the GB to the 3:00 position. The gold (also lead-probably some tin/treated steel)will produce a high tone whereas small iron will give you a low tone.

Darn it Eric- after I finally got my Ferrous Hound up and running you have already made it obsolete.

George

 

[Anonymous]

I was wondering how you would gauge the FH efficiency hunting inland in mildly negative ground for coin hunting, in both modes? Has anyone ever been able to use a full PRG on a pulse, or is a phase angle required with a PRG?

 

[Anonymous]

This would make for an additional momentary 'on' switch, with a preset load.

 

[bakergeol]

First the signal from the FH is all or nothing. There are no weak signals with depth so I question if minor ground mineralization changes will have an effect.

Using the FH with a PI for gold hunting would be advantage, however,strictly for coin hunting I would not want to employ the FH with a PI except for the GS5. Yes it would help but you have depth issues.The issue is the incredible amount of thin flat and small iron out there at sites heavily used by man. A quarter size paper thin piece of iron will only be detected at 3". A bottle cap only 5" to 6 1/2". Folks who use PIs at the beach recover these items far deeper than this. The FH will help on a lot of iron but you are going to have to live with the thin iron depth issue. A good VLF with solid discrimination will still have a great advantage.

However, the GS5 I think has greater potential than other PIs(possible exception of the Infinium) for coin shooting as you have a ferrous/non ferrous identifier in the 10:00 GB position.

The FH would you give an advantage when used with the GS5 in the GB 3:00 position as some heat treated steel and new bottle caps produce a high tone just like gold and nickel. These would be readily identified as iron with the mag as long as they are not deep. It would be a way of further IDing the target.


George

 

[Anonymous]

First; Inland hunting coins in Very mild ground minerals, looking for coins, and small circular, disc shaped, or steel bottlecaps are not an issue, mainly linear iron from 1/2" to several inches.
Second; Hunting in saltwater marshes for Civil War Artillery shells in ground where no VLF of any kind will work. Projectiles will be from five feet down, minimum, and generally no smaller than four inches in diameter. Again small linear ferrous trash will be present.
I know Eric's detector's, as I have an older one, and I tend to gravitate toward him.
Between the GS-5 and the Infinitium, and what type of loop would you recommend?

 

[gatorguy]

I would use the Infinium with the standard coil that comes with it, perfect application for one of the reasons it was made. Don

 

[bakergeol]

First off I can't argue with gatorguy as the GS5 is so new that coinshooting probably has not been examined closely with the GS5. Even I have only used the GS5 for gold hunting. So we just have to wait to see how the GS5 compares to the Infinium for coin hunting.

However, the GS5 does have the potential for a good PI coinshooting detector with the obvious limitations compared to a discriminating VLF. Coming off the PI mode to the 10:00 GB mode, small high conductors like silver and copper will produce a small low tone whereas all iron will produce a high tone. Actually you can identify small silver such as dimes and quarters at very shallow depths in the GB mode. After receiving a low tone you place the coil on edge and sweep again to receive a high tone. Although this is unique for small silver it probably would not be practical in the field. Coinshooting with the GS5 is still a new frontier.

With regards to the detection of 4" vertically buried shells below 5' I wonder if any PI could do it? Perhaps a GP3000 or GP3500 user with a 25" nuggetfinder would know as the GS5 is so new. If it was not possible with a GP3500 it probably would not be possible with the GS5.

I might throw in something here that I have always wondered about. There is a magnetometer made in Canada called the Magnawand. It is a utility locater which has a waterproof stem. It differs from other magnetometers as it can identify horizontal iron trash from iron objects with shape. Nothing like digging 5 foot holes for trash. Of course waving this stick around in the middle of a swamp would be time consuming and certainly not fun.
http://www.magnawand.com/
I have always wondered if it could be used as a cannonball identifier.
Its cost is reasonable ($450 if bought in Canada, $650 if bought in the US) which is not too far off the cost of a large Coiltek or Nuggetfinder coil. I would locate a dealer and try one out in the parking lot to see if it has the depth.
But of course this is just me.

Have Fun
George

 

[gatorguy]

my comment was geared more towards his underwater work, the GS5, unfortunately can't go there. Don

 

[Anonymous]

Is the "Magnawand" a differential magnetometer like the Fisher FX-3? Have you come across anyone who has used a mag/meter called "Earth Magnetometer"[TM]? I'm sure a pulse has the potential for deep ferrous objects, and Eric has said that an 'orthongol' loop configuration will work.

 

[bakergeol]

Yes it is similar to the FX-3. The engineer who designed this tried to produce a version of the Magnawand which could be used with a PI. However,he was not successful. No I have no knowledge of a mag called the "Earth Magnetometer".


George

 

[Anonymous]

n/t

 

[Anonymous]

I tried a Fisher Mag-Stick years ago, and it does not have the range for Deep shells. But they are finding success in locating well-heads that were capped off in the 1950s-60s when some wells were too deep to pump profitably. I've hit well-heads 12 feet down. Its a good companion for a pipe-locator.