New Zealand Gold Prospecting & Metal Detecting Forums Archive

Well Ronnie

It might help if you tell the guys what Detector you are actually using.

Cheers Trev aka " The Hatter"

I have used the garret before check the iron mask is off try some non ferrous targets like copper,brass,etc the discrimmination scale goes to 100 nuts and bolts are on the low end try a bit of everything in a row to get an idea of what the high and low tones sound like and there numeral value.good luck and happy hunting

Hi ShaneE

I've read the manual cover to cover a few times, so wherever I (or the machine?) am going wrong isn't something as simple as the iron discrimintation -I've got that turned off, and have tried with varying sensitivities, with even maximum sensitivity not picking up the targets above 15cm depth. However, I am new to this, so there may be a slight tone or something that I am not hearing correctly.. Would you recommend using a headset while using the machine? All of the photos in the manual, and a lot that I have seen online, have shown people wearing earphones while using the metal detector, but there weren't any with the machine I was using. I am wondering if that is likely to make a difference in hearing some of the tones when the signal is weaker (for deeper targets)?
Interesting what you said about the soil being dry -I haven't heard that before!

Hi creamer
The main problem I have been experiencing is that I have only been able to detect the targets (nuts of 10 or 12 mm thread diameter) to about 10-15 cm depth, whereas I need to be able to find them at up to 30 cm depth and have been told that the device should be able to find them at that depth (by someone else on the forum that also has a Garrett At Pro).


We have decided in the last 24 hours to use ball bearings rather than nuts (there will be cattle where I will be running my trial, and though it is unlikely that a cows hoof would be damaged by a nut, a ball bearing is even less likely to cause damage), so I am now looking at using ~20 mm diameter ball bearings as targets.

Lead has been considered but was deemed not to be appropriate as it has a risk of environmental issues, as the trial will be on farmland, draining to waterways and of course there is a possibility that we might not recover all of the targets.

Thanks for your wealth of information on this and my other topics on the website Mudwiggle!

I am waiting to hear back on if the head phones can be tracked down. Have talked to who I'm borrowing the detector from, and they weren't in the box, so they're asking the last person who used them. Hopefully they turn up, as it is not a standard audio jack, so I can't use my own.. (as I'm sure everyone on here knows!).

If that's not successful, will bring up lead again with my supervisor, but I don't think that it will pass..

Does your Garrett have a 1/4" jack?? Here's a pic of mine. I have a 1/4" to 3.5mm adapter for my stereo- but I think it's not going to do the trick here! ;)


We'll be surveying them in with a total station -so it will be accurate to approx a centimeter (or less? don't have the accuracy for this at hand). This doesn't mean that we know where they'll end up though! If one gets stuck between the cloves of a cow's hoof, then falls out 100m away, we might not be able to locate it. So surveying them in wont help with this!
The plan is to put short horizontal transects at selected positions (angle/shape) on the slope, and we will be using approx 2ha in the corner of a 6ha paddock with cattle in it, and comparing soil (ball) movement at different slope angles and different parts of the slope, such as convex (crest) and concave (toe). The crest of the slope is actually highly likely to move, and is expected to have the highest net movement, as there is no soil coming from above it as the soil creeps down slope. Further down the slope, soil will also move downhill, but will be replaced by soil that was above it, so while soil TRANSPORT occurs, soil EROSION does not as net soil volume (is expected to) change very little. Meanwhile, it is considered that erosion does occur at the crest of the slope, as net soil changes. Also, given that we will have cattle walking around, I think that we will get quite a high degree of movement on all parts of the slope (though the degree of movement is likely to be different) -and this is what we're trying to measure. How much accelerated movement the cattle and winter crop grazing system causes, relative to pasture.
Your idea for putting some posts around one of the ball bearings is good, but it doesn't account for the soil level potentially changing though deposition of soil coming from uphill, or overland flow of water eroding the surface, therefore changing the reference level.. Beside the fence will have grass rather than exposed soil, so I would expect that their roots would prevent any vertical movement. It is a good idea though, and is perhaps something that I can test in the lab with some soil samples :)

I am in chch if you would like me to take a look on a sunday evening in hagley park, I can compare to GBPro or Minelab PI (PI are better depth but not good if you are finding lot of rubbish metal as well). You should test away from mains sources eg park lights and houses though less problem when not homemade detector.

I would suggest you make some circles out of copper wire, that would be easier to find and discriminate. Aluminium cans are very hard to miss.
Solid items harder to find than rings due to rings eddy currents. You can go deeper with bigger detector coils and also with PI (some Minelab) but at expense of target ID.

Keep posting your detecting and geology discovery, preferably on the same thread which makes it easy to Watch

Is it a university project or what