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Rick N

March Issue Of Icmj

59 posts in this topic

This is the type of gold on which the SDC 2300 and GPZ 7000 by Minelab do quite well. It's long been known that most PI detectors respond poorly on spongy and dispersed specimen gold.

It is something like comparing a solid gold men's wedding band and a long fine link chain - both may be the same weight and alloy of gold, but the tiny chain responds poorly if at all, even when pushed into a mass, while the ring sounds off boldly at the same distance from the coil. The individual particle of gold are small and like the small chain links, that is what counts.

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Rick,

 

The SDC 2300 uses MPF (pulse) technology as well as the GPZ 7000 which uses ZVT (Bipolar pulse) technology.

 

Pulse technology is good for "Horseshoes and Hand Grenades" as illustrated on the Minelab website.

 

Best way to test the response is to check them out at a dealer if you have a chance!

 

Verify the gold content by crushing, screening and panning. Then get the gold assayed or refined.

 

Good luck! :)

 

- Geowizard

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Pulse technology is good for "Horseshoes and Hand Grenades"

Have you ever actually run a hand held PI metal detector by Minelab, Whites or Garrett?

If so you would know that running them in a dealer's shop is quite difficult because of EMI from surrounding power lines.

I think your statement shows a gross lack of knowledge about the subject.

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Rick,

 

X-Ray (XRF) measures only a small, approximately 1 centimeter "window". If your sample was pulverized into a uniform blend, then it's close - there's still a problem with "nugget effect" with XRF.

 

XRF should be calibrated. There are companies that sell calibration standards for XRF.

 

XRF is also prone to interference between metals. The response peaks overlap.

 

- Geowizard 

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Geo, it was a specimen sampling with enough exposed AU for the results I guess. 

 

Rough estimate.

 

30 power

 

Gossa30%20pwr.jpg

10 power

 

Gossan%2010%20pwr.jpg

What is this material called?

gossan.jpg

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Rick,

 

Yes, I understand.

 

Another feature of XRF is that x-rays don't penetrate gold and silver. The metals are too dense - just like lead is a shield for x-rays,

 

From the results you have Gold and Silver! :)

 

- Geowizard

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Thanks Chic and Jim. Enjoying the workout. I'm treating the work as a step through history, reliving the old miners hands on the pick and shovel. I do have some modern conveniences, Home Depot 5 gallon buckets.

Hope to share more as I learn and continue to uncover the secrets.

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Chris, about your next article, I would be interested in the various formations, Calaveras, Mariposa, etc. In just our area, the formation changes in just a short distance. Also interested in the slip fault and fault systems.

 

I just read an article (goldhunter.m.webs.com) talking about the different types of shoots, structural and chemical. I would love to know more about determining the difference.

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That's a fine idea - I'll do up an article on Rock formations of the Mother Lode country. Look for it in an issue of the ICMJ in the next few months.

 

The formations change in a short distance going east-west, but run a long ways in a North-south direction. Its because the formations are compressed from a plate collision with the force coming in a westerly direction.

 

Rick - any more gold coming from that spot?

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Chris,

One from yesterday. 370.2g and SG test, as is normal for this mine, showes a negative value. Pockets in the quartz throw it off.

11899817_734422553356713_13412441408992011954659_734422900023345_750096629177865

The piece has good value running up through the stained area. Will crush and process to see results. I'll pm you some images of the system as it is becoming more revealed as I clean out the loose dirt and rocks.

11915904_734245820041053_380988789171222

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Any kind of air in the porous parts of the rock will throw off the readings quite a bit. The whole method of determining percent gold in quartz assumes pure gold and pure solid quartz. Anything else like air and it wont work.

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Chris,

 

I've followed the old timer down the edge of the reef on the right and to the left he seemed to be working under that large rock as the seam twisted and diverted. Lots of action going on around this area. I think I need to follow the direction straight down. Thoughts? 353° strike and 48° dip.

11915904_734245820041053_380988789171222

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Its hard enough to read things in person - in a photo its much harder. The rock is weathered, and I've got a view of just a couple feet. There is no way I can look at that picture and tell you which way I would dig if I were there.

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Geo, been sampling as I go. Will continue to do so.

Just started on the boxworks on the hanging wall of the quartz seam. Will test sample.

Decided to follow the seam on the surface and see what's what.

 

Thanks.

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You may be close to a significant discovery.

If you know this, why not tell us how far away from that significant discovery he is, and in which direction.

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