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Gold Spear

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Hi guys, have any of you used a gold spear. If so....what are your thought on them? The fact they aren't around any more, or are they?, sort of suggests they weren't too popular. Thanks.

Good luck out there

JW :smile:

  

 

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Used one here in Arizona , seemed like ya almost had to stick the probe on a piece of gold to get a reading.

Did not use it but the one time, glad it was a loaner...:biggrin:

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Old prospector I knew years ago in Arizona *as well* took me out and showed me how to use his gold spear.  It worked well for locating fine gold streaks in gravels.  You count the number of strikes as you probe and the higher the count the better the run.  Biggest problem is pushing it into the gravels.  Have not seen another one used since then but there may be a few floating around still.  Still nothing replaces sample panning but the spear can clue you in.

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I used to be a Goldspear dealer and had one briefly myself. It is not a pinpointer in the classic sense. It as far as I can tell is basically a conductivity meter. The tip of the probe is made of alternating layers of tungsten carbide and an insulator. Conductive items coming into physical contact with the tip bridge the small gap between the tungsten carbide layers to complete a circuit. A sort of minimal discrimination exists between conductive metals and less conductive mineral matter.

From the Online Manual (use Google Translate) 

How it works: When the probe is stuck into the ground, in sand and gravel layers in and along the watercourses, every mineral grain that the tip comes into contact with is measured. The measurements are electrical and it is the so-called self-potential of the individual mineral beads and their ability to conduct current as measured. This measurement takes place in less than one thousandths of a second.

Different minerals have different electrical properties, which therefore give different electrical values. One can say that each kind of mineral has its own "electric fingerprint", which is the same as the sour mineral found in Småland or China. Because there are thousands of different kinds of minerals, there are as many different "fingerprints". 

The electrical values measured by the tip are led into cables through the probe (and possibly connected extension tubes) up to the electronics where they are analyzed. Goldspear divides the minerals into five different groups, one uninteresting and four interesting: 

1) "worthless minerals" 
2) "blacksand" 
3) "Minerals who are poor on metal"
4) "Minerals rich in metal" 
5) "Pure metals, Gold - Platinum" 

goldspear-diagram.jpggoldspear-gold-spear-detector-control-box.jpg

There are two very large issues with the Goldspear. First and foremost is the fact it is a probe and not a detector per se. You must touch the item sought for with the tip and missing the item by 1 mm means you miss it entirely. The theory is you are looking for widely dispersed fine gold to trace back to the source. Here is a brief English language page describing the general theory of operation:

http://www.metalldetektor.se/gsmethod.htm

It sounds nice in theory but the reality is you cannot push the probe more than an inch or two into hardpack material. You might possibly drive a steel bar to punch a hole first, then insert the Goldspear probe into the hole, except for problem number two. Again, from the online manual link above:

"Where the field is heavily contaminated by human activity, it is almost pointless to search gold with Goldspear."

That about sums it up. Any almost microscopic bit of man made metal will cause a false signal. Mercury can contaminate the probe tip rendering it useless. My tests at a 100 year old placer mine produced signals everywhere I probed, with nothing to be found when the material was panned. An area has to be almost totally free of man made metals, and few placer areas fit that description. Back to the first problem. Driving a steel rod to create a hole for the Goldspear will almost certainly cause the hole to be contaminated by almost invisible bits of steel shed by the rod as it is driven into the ground.

OK, so this thing sounds about useless, right? Not entirely. The one scenario I came up with where a Goldspear might be useful would be in looking for virgin placer deposits covered by thick sand or muck or organic layers. For instance, a bench deposit in Alaska with two feet of tundra/moss/muck over the gravels. The Goldspear can easily penetrate this soft material to reach harder gravel to get readings on virgin material on flour gold a regular detector would never sense. Even then the whole thing seems pretty hit and miss. I have more faith in a shovel and gold pan.

Very much a niche product and it was not cheap - like over a $1000 if I recall correctly. I don't think they make them anymore though the manufacturer website is still up and running. From the website:

Goldspear Specifications

Electronics unit: Height 220 mm., Length 190 mm., Width 55 mm. Weight: 700 grams.

Battery: 9 volt standard battery.

Piezo loudspeaker: Length 70 mm., Diameter 20 mm., Weight 20 grams.

Measuring tube with tip (Probe): Stainless steel and carbide. Weight: 800 grams. Length 1.2 m., Diameter 15 mm. (Coupling diameter 18 mm.).

Extension pipe: Optional accessories. Naturally oxidized hair dermal tubing with quick couplings. Weight: 400 grams. Length 1.2 m., Diameter 15 mm. (connecting diameter 18 mm).

Complete with peripherals and an extension tube weighs Goldspear less than 2 kg.

Sensitivity is difficult to describe but if 1 gram of gold (0.05 mm grain) is evenly distributed in one ton of sand, Goldspear gives an indication every two decimeters as the probe is stuck in the sand. These are statistics, in fact, gold is never even distributed but is usually concentrated in layers or pockets. These are easier to find than in the (unnatural) cases where gold is evenly distributed. In addition, the sensitivity can be doubled by stopping the probe twice or tenfold if it is stabbed ten times at the place you are looking for. 

Minimum detectable gold grain: less than 0.05 mm.

 

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Hi guys, Thank you all for your comments, feedback & advice. I have always been intrigued by the gold spear & one came up on our online auction site. It was in almost new condition. It closed on sunday & sold for NZ$400. I was away all weekend jetboating on some West Coast Rivers (non gold related)  & so missed the close of the auction & I didn't see any of your comments until monday. Probably glad I missed out on it :rolleyes:  Cheers all

Good luck out there

JW :smile:

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Last time I looked at the mfgr website, this thing was over $3500.I believe the website is in Sweden. I had a used one many years ago but it was about useless and too hard to figger out.

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