First Experience Of Mineralised Soil

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Wigeon
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First Experience Of Mineralised Soil

Post by Wigeon » Wed May 24, 2017 12:43 pm

Last Monday I was detecting on a friend's farm about ten miles north of Stamford in Lincolnshire.
I had identified a feature that showed as a mark on aerial photos. The landowner said that it was a 'wet hole' but knew nothing else of it. His family have farmed the land for three generations.
I wondered whether it could be a spring.

I started detecting from the north side of the feature and the e-trac was chattering madly but none of the signals were repeatable. I tried noise cancel and going to auto sensitivity but nothing would settle it down.
I persevered until I got south of the feature, when I started to pick up some junk. For example a front hubcap from a Fordson Super Major tractor and a broken harrow tine.

The ground continued to chatter but to a lesser degree. I must have managed to get my head round it as I detected a signal at 9 to 10 inches that turned out to be a button of 15mm diameter.
When I got home I managed to identify it as a Victorian General Post Office uniform button. I also found a George V penny at similar depth.

The field is old pasture, which was last ploughed for re-seeding more than twenty years ago.
The soil has a reddish tint, so possibly high iron ?
Later whilst having a cup of tea with my friend, he told me of a heap of iron slag that he and his father had removed from another part of the farm, near an old watercourse. So I am now wondering if the area was used for ancient iron working ?

I asked whether there had ever been any 'green waste' on the farm but thankfully not so.
Not all the fields are so highly mineralised and I am not at all sure of what to make of it.
The E-TRAC clearly still works in such conditions but it was a new experience for me coping with it.


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Resurgam
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Re: First Experience Of Mineralised Soil

Post by Resurgam » Wed May 24, 2017 1:42 pm

Just a thought; could it be an ancient iron working site? Could be a clue to better finds, perhaps? ::g
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Re: First Experience Of Mineralised Soil

Post by clint » Tue Jun 27, 2017 10:06 pm

Interesting. ...what's your settings? Try backing off the sens and slowing your swing speed to VERY slow. Increased sens also means means the machine "sees" more mineralisation so don't get hung up about knocking it back a bit. Noise cancelling only knocks out emi /radio interference the ground balance is automatic. Also whether you run in ferrous or conductive tones if you get a "good" AUDIO signal...DIG IT as mineralised ground will make your number id worthless.

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Re: First Experience Of Mineralised Soil

Post by At Digger » Tue Jun 27, 2017 11:26 pm

As already said, just reduce your sensitivity and dont worry about depth loss as it wont loose much depth. Better to have a quiet machine even if it does have a slight loss of depth.

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Re: First Experience Of Mineralised Soil

Post by Wigeon » Wed Jul 19, 2017 9:09 am

clint wrote:
Tue Jun 27, 2017 10:06 pm
Interesting. ...what's your settings? Try backing off the sens and slowing your swing speed to VERY slow. Increased sens also means means the machine "sees" more mineralisation so don't get hung up about knocking it back a bit. Noise cancelling only knocks out emi /radio interference the ground balance is automatic. Also whether you run in ferrous or conductive tones if you get a "good" AUDIO signal...DIG IT as mineralised ground will make your number id worthless.

Cheers

Clint
Went back to the farm yesterday and checked out the area that may have been an old watercourse, below where my friend had removed slag. I found the bottom of the dip to be very mineralised with lots of chatter, so reduced the sensitivity to auto -2, which settled the machine down. I dug some of the repeatable signals but they turned out to be 'nuggets' of slag, so clearly ancient iron working has taken place there. The signals had broken through the discrimination but had that 'screechy' tone of iron about them.
As I moved up the slope on both sides, the mineralisation decreased considerably, so appears concentrated in the area of the 'old watercourse'. Whilst the weather was good for a sun tan the ground was bone dry down to 9 inches.
I was using an open screen, except for lines 35 to 31 ferrous discrimination in conductive. As Clint predicted, the numbers and depth indication were all over the place.
Clearly there had been ancient human activity on this field, so perseverance would seem in order.
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