newbie questions

[azmetaldetector]

I am going to a ghost town soon that was once a gold mining camp. I will be using my MD at the site, but not specifically to try and find gold. If I stay in all metal mode will I pick up flake or nuggets, or do I have to go to Gold Prospecting mode? (I have a White's MXT).

 

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[Nicksan]

I am not a nugget hunter but I just read another thread that says that you can pickup flakes, but I would think that would be very hard. I would assume prospecting mode is all metal with whatever adjustments you make. I have not read through the manual about nugget hunting yet, but will soon. Heres a link to whites users manual page.? 8)

http://www.whiteselectronics.com/manualsw.php

 

[Earl]

I would use the prospecting mode on the mxt and dig it all. Probably won't find any flakes but you will be able to pick up the small nuggets. I have read great things about the mxt, it is supposed to be a good machine. Just my 2 cents worth

 

[bakergeol]

Here is how you use the MXT for gold nuggets -It was written by Steve Herschbach. Pay attention to his settings and what he does to ID iron.

Article by Steve Herschbach in the Alaska Gold Forum

Hi,

I've used a lot of VLF gold nugget detectors over the years, but have been particularly happy with the White's MXT. One huge reason is that unlike other dedicated nugget detectors it has a LCD based visual discrimination indicator (VDI) system. I'm sure White's included this mainly in line with the MXTs intended goal as a multi-use machine. But it turns out that for certain nugget detecting tasks the MXT has extra capabilities only now being realized.

Alaska has huge areas of old mining tailings that provide great opportunities for nugget detecting. Virgin ground is covered by overburden thicker than detectors can penetrate in most cases, so in many areas these tailings are all there is to detect. And the nature of the old operations were such that many of the very largest nuggets were lost into the tailing piles.

But there is a huge catch. Some of these tailing piles contain incredible amounts of iron junk, and at any depth. Some creeks were mined many times, and so old campsites and dumps were churned up and mixed in with the tailings. This junk can be anything from rusted flakes and slivers of steel on up to cans, bolts, washers and nuts, and finally even 55 gallon drums, and various large steel plates, pipes, boilers, or even larger items.

Ganes Creek, Alaska is possibly the best known of these locations. New visitors from areas in the western US where the Minelab SD/GP detectors have reigned supreme have had a hard time adjusting to the concept that there is such a thing as too much power when coupled to a poor discrimination system.

If you run a Minelab at Ganes Creek here is a likely scenario. You are in a field of fist-sized and larger cobbles. You get a nice little signal and no iron blanking. So you start to dig, as best you can in a pile of rocks. It is as much hand excavations at times as digging. After some effort you are at two feet, signal is louder, but no target. You pull out another cobble and half the hole falls in. You pull all those rocks out, and get another foot down. 45 minutes has passed. You pull out another rock and the hole caves in again. 15 minutes later you are at 3 feet again and really tired. Over an hour has passed since you started this hole. The signal is very loud now...too loud really. You dig down a bit more, then some more, and the whole thing caves in again.

You walk away in disgust.

How deep can you hit a large can with a GP 3000? How about a 2'x 2' steel plate? How about a 55 gallon drum? They are all there waiting! Normally you would just figure it is junk past a certain depth, but the big question always must be how deep could you hit the 35 oz or 80 oz pieces found this summer, or the 122 oz chunk that stands as the largest found at Ganes so far?

Because of this huge junk problem VLF detectors have generally been the way to go at Ganes. The low mineral conditions means they keep you from wasting huge amounts of time going after junk targets. Most any good VLF machine works well for this, but the MXT gives you some extra capability once you learn its tricks.

Four things to know. 1. VDI numbers increase as the nugget size increases. So a ? oz nugget will read around 25 whereas a 1 oz nugget will read around 60 and a 2 oz nugget will read around 70. 2. The larger a nugget, the deeper you can detect it 3. Certain steel items can give positive VDI numbers and 4. VDI numbers are ?pulled down? the deeper the nugget is buried. So a ? oz nugget near the surface will read 25, but at depth might read 10, and at max depth may finally read at 0 or lower and actually be called iron.

This last point is very important, as if you run a Fisher Gold Bug 2, or Tesoro Lobo, or Troy X5 is disc mode to tune out iron, as is normal for many people at Ganes Creek, deep nuggets may read as iron. If they are, the machines will reject them, you will get no signal, and walk past the nugget.

With the MXT I like to run the detector in relic mode, with the disc set precisely at 2. Non-ferrous items will give a hi tone, and ferrous junk a low tone. If you get a faint lo tone, the first thing you do is kick and inch or two off the surface. If the VDI number rises, keep digging! Targets that read iron initially and rise will often turn into non-ferrous readings? hopefully gold. If the VDI number stays the same or goes even lower, you have an iron target. With one of these other machines you would need to run in all-metal, then switch to discriminate mode to check the target. If the target was faint, and now disappears, kick off the surface, and check again. If it now beeps, keep digging. The end result here is the same, but the MXT makes it easier as there is no switching between modes needed to do this kind of checking.

Where the MXT really shines are on ? oz to ? oz nuggets. Let?s say you get a reading of 24. OK, that is about a ? oz nugget. Now, we know that you can hit a nugget this size at 10-12 inches. So you dig a foot, and no nugget. A large, deep iron item of a certain type can also give a 24 reading, but these large items can be detected much deeper than a ? oz nugget. Dig them up if you wish, but once you go past that depth at which it is reasonable to find a nugget corresponding to a certain VDI number you are wasting your time. This method eliminates digging those false positive signals from deep items like steel plates. With the other VLF units the lack of VDI number means you have no way to judge the potential nugget size and so you end up digging deep for what may be a very large nugget when with a MXT you would know the VDI number corresponds to a smaller nugget. For the many smaller nuggets that are found at Ganes this method is pretty foolproof once you get the hang of it.

Finally, certain non-ferrous items can be found in quantity, particularly things like .22 shell casings. If you get into a bunch of these, they are usually very shallow. You can easily determine the VDI number of these multiple identical targets and then simply ignore them. You would miss a nugget with an identical VDI reading, but chances are a nugget will vary enough to make it stand out. No way to do this with a non-VDI unit.

Many thanks to Dave Rankin for pointing out the correlation between nugget size, VDI number, and possible recovery depth. It was a real eye-opener once I put it into practice at Ganes Creek.

.
[2 edits; Last edit by Steve_Herschbach at 05:09:31 Thu Nov 18 2004]



---
Steve Herschbach
Recreational Miners Association
www.recminer.com



George

 

[MUD(S.W.A.T)]

I would not even use the metal detector at first! I would just pan for gold for sometime. You would be surprised at what they left behind downriver and up river. Downriver what they kick up, up river goes down stream. Look for shale rock and break open the cracks and get the gold from there. Look for old river beds too.

Keep @ it and HH!!