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So I took my SDC 2300 to a location in California which I hadn't visited in a couple years because the last few times I'd been there it was a skunk. I get started and I hadn't been detecting even 5 minutes when I dug the first target was a little nugget. The second target was a nugget as well. I've only been able to re-work a small part of this area as I keep digging more little nuggets and I don't want to walk away when there are still golden targets. I was shocked to see how much gold was just sitting there in a spot I know I have gone over before at least a couple times. So in about 7 hours detecting, I have 21 nuggets with a total weight of 3 dwt, just over a tenth of an ounce. Yah, they are small, but lots of fun to dig. The largest of these, a 0.8 gram piece, gave a strong down-up tone. Its just surprising to see how small a nugget gives a down-up tone. You can see these nuggets are very rough and have not traveled far. This spot is a lot more interesting now that its yielding a bunch of little gold.

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AS long as there are lots of small pieces - and those are the most common - then they add up. I am just as happy with an ounce of those gold nuggets as I am with a single one ounce nugget. Perhaps even happier, that is nice stuff!

 

It is easier to make an ounce of gold doing what you are doing than finding a one once nugget by a long shot.

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Fine Gold is a misnomer. The best small gold setting on the GPX 5000 is Sensitive Extra. Fine Gold does pull small gold out of extremely mineralized ground, but for less mineralized conditions Sensitive Extra is more effective. See the Timing charts at http://www.detectorprospector.com/gold-prospecting-equipment/minelab-gpx-4000-4500-5000-manuals-timing-charts.htm

I have seen some amazingly small stuff found with the GPX 5000 and I am sure some of the gold being found by people with an SDC can be found with a GPX 5000. But the SDC will find it also, plus gold the GPX 5000 will not. That is the whole reason it exists.

“You will find more small nuggets and fine-threaded specimen gold in mineralised soils with the SDC 2300 than any other gold detector, including the GPX 5000.”

- Bruce Candy [Chief Scientist Minelab Electronics, GPX & SDC Inventor]

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Chris… your rough character gold impresses… regardless of size. These are attractive samples as are many others you’ve posted recently. I would be a bit surprised if you sell your quality gold finds, but should think this size range would be much easier to market at a good price if one was so inclined. 

 

I’m surprised at the 0.8 gram piece producing a lo-high tone too. It seems to indicate a very low conductive GB position compared to my PI units over my ground. It would be interesting to know where that nugget target IDs on a VLF unit. No need to reply to this… just thinking about your “down-up” signal comment… congratulations on some very fine looking samples. 

 

Jim.
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goldenoldie - this was never intended as some sort of head to head field test of the GPX vs the SDC. I'm sorry if you got the wrong idea. I know I have prospected at that spot with the GP Extreme, but cant remember if the last time I was there I had my 5000, as I said, its been some years since I detected this spot. That said, I am sure at least one of those pieces should have been found with the Extreme, but because I found a number of small nuggets with the SDC, I was digging every target. Consider this: If I pass over an area and dig a number of trash targets and no gold, I am likely to move on - its what most guys would do, and that is what happened at this spot before. On the other hand, if I dig several pieces of gold and some trash too, I am going to investigate much more carefully and most likely dig every target, good and bad. At this spot with the extreme, I got nothing but trash. With the SDC, I got a whole bunch of little nuggets, and was carefully digging everything, and the ratio with the SDC was nearly equal, trash iron and gold - about the same numbers of each, so at that point, I am happily digging everything.

Jim - I dont know why it does down-up at so small a size, but it is consistent. I got a solid nugget in Alaska that ran close to a gram and it was a down up signal too. On the other hand, I got a specimen piece that was high in gold - mostly gold by weight and volume, and it weighs just under 12 grams, but it was a high low - it is not so solid as the two little pieces that did lo-high, even though the specimen has loads more gold.

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The tones are an artifact of the ground balance system on a ground balancing PI detector. The White's TDI easily displays this with its manual ground balance. What delivers a lo-hi tone versus a hi-lo tone changes depending on the ground balance setting.

The Minelab units have two ground balance settings or "channels". The timings vary the detector pulses and ground balance scheme to deal with different ground conditions. The tone delivered by targets change depending on what timing you chose on the GPX 5000.

The SDC 2300 is using a much shorter pulse delay combined with a version of the Enhance/Fine Gold timing scheme - see http://www.minelab.com/__files/f/240330/KBA_23-1%20MPF%20Technology.pdf for details. This means the tone results on the SDC 2300 are not consistent with most other ground balancing PI detectors and anyone coming from other models should ignore anything they think they know about the tones and what they may mean regarding target identification. In general, almost everything except tiny or dispersed gold delivers a lo-hi (down-up) tone. Even extremely small ferrous trash will give a lo-hi tone as will some surprisingly small gold. Lesson for now - dig all targets with the SDC 2300.

See Nenad's post at https://www.prospectingaustralia.com.au/forum/viewtopic.php?pid=89288#p89288 for photos of man made items that deliver different tones.

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The question is that the PI with Iron Check and kind of discrimination will be better fot trashy areas... than SDC or not. 

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Chris...  I have a wide variety of silver specimens that illustrate structure exerts a very real impact on PI GB scale positioning. Despite the elevated gold weight, I think it is the structure that positions the 12 gram specimen on low conductive side of the GB tonal break.... hence a high-low tone response.

One apparent result compared to my GBPI units is a dramatic shift in the GB tonal breakpoint to a very low conductive placement on the GB scale… a foil to low nickel GB position seems indicated from the forum examples reported to date.

Based on those reports, forum readers should realize that it is not possible to differentiate any ferrous from non-ferrous based specifically on signal tones, but thanks to the information above from you and Steve, readers can understand why that is the case. 

Jim.

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Went out again today with the SDC 2300 to the same place where I got the 21 nuggets recently and today I got another 6 nuggets with a total weight of 3.2 grams or a bit over 2 pennyweight. it brings me to 4 pennyweight with the SDC here. I am finding nuggets in groups at this location, so I also brought in my dry washer for a test. By seeing all the small nuggets in an area, the SDC 23000 is doing a great job of identifying the range and shape of patches that can then be worked by various means - scrape, dig, sluice or dry wash. Because this place is dry, I brought out my dry washer. The dry washer showed that yep, there is tiny gold here that is too small even for the SDC, which I can collect. I spent the bulk of the day detecting, the dry washer was only for a test, but I was happy with the results for the limited time invested, I got roughly an additional half gram with the dry washer. Still loads of places to hit with the SDC and the 2300 is identifying places to dry wash in the future as I go.

 

Sorry for the low quality pic, I have laptop computer problems which are limiting my photo options.

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