Depth Question

Prospecting Australia

Help Support Prospecting Australia:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Aug 22, 2013
Messages
1,646
Reaction score
1,816
I got asked this & not sure with to-days gear the correct answer . :(

What depth in medium ground can a top detector clearly signal a match head sized bit of gold & smaller half a rice grain bit ?
 
I wouldn't consider myself seasoned by any means but on the mentioned size which I'm a champion at finding :( :lol: I'll bag a decent one, one day my experience is around 30/40 millimetres. The thing that surprises me is once you find a few bits in an area of a few square metres and then it stops yet come back another day at a different time and in the same place you find a few more. Is it operator, ground mineralisation, battery :/ one things for certain they don't grow back.
 
Match head sized, lets say its the actual size and shape. With a 12 flat NF I reckon a solid bit that size my best is 6 inches. Have done it numerous times. Often expected it to be bigger but yeah Id back that in no worries. Not always or often a stand out, but yeah no worries 6. Done it no probs with a flat 15 too. Mongrels sometimes do a dip signal and stooge me thinking its bigger n deeper. Often those ones are more solid in make up. The more open airy ones are usually ups.
Flats often make it harder to pick what it will be, up or down signal, than a conventional wind I have found.
 
JD3 said:
Match head sized, lets say its the actual size and shape. With a 12 flat NF I reckon a solid bit that size my best is 6 inches. Have done it numerous times. Often expected it to be bigger but yeah Id back that in no worries. Not always or often a stand out, but yeah no worries 6. Done it no probs with a flat 15 too. Mongrels sometimes do a dip signal and stooge me thinking its bigger n deeper. Often those ones are more solid in make up. The more open airy ones are usually ups.
Flats often make it harder to pick what it will be, up or down signal, than a conventional wind I have found.

I have had that many times get a good drop tone and it turns out to be tiny,a little disappointing especially when you are expecting a gram or so
 
Wehla - mild ground, 18" advantage mono.

2 x match head size and round in shape. One smaller.

Faint signal - 100 mm dig approimately x 2.

.90 gram & .40 gram.

Donated to Patricks Cancer Care fundraiser Lanecoorie last year.
 
Depth of finds comes down to how accurately you "pin point" your target.
The deeper the hole the wider the mouth, eventually your "match head" falls of the widened hole walls into the bottom.

Woweee, got a tiddler a foot down! :lol:

And the question you hear every other day, "How deep does it punch?" :lol: :D
 
yep...plus people often take a few inches out, stop and swing the coil, go again with a few more whacks of the pick then stop and swing the coil again and find the target is out in the spoils.
They then measure the hole and marvel that they heard that tiny bit at a measured 8 inches even though every whack of the pick might remove 3 or 4 inches and that little nugget popped out 1 or 2 whacks ago.

The only way to reliably measure the depth of a target is when you see it still embedded in the bottom of the hole. What usually catches your eye is the shiny pick mark you've left across the top of it. :mad:
 
When I hear the the wondrous claims of some prospectors nugget depths, I think they must be measuring the depth of their holes with elastic tape measures!!!!
 
Yep those sized bits especially in the dry run offs close to the surface have mostly been scored in the last 10 years with hi end detectors on known ground , Tuna's earlier post said a few centimeters at best for the larger sized bits , he would know !

Go that bit deeper & some of those little run offs are still virgin !

I cherry pick those natural dry run offs taking samples to test over wide areas just like the old doods did in the 1890s .
Seems they missed many runs or 130 years has made some changes .

Thanks for all who posted'
Jack .
 
G'day

As mentioned there are too many variables to give a precise answer on what depth a nugget of any size can be found, small nuggets seem to be primarily found in the first 150 mm, maybe that's just the norm for a higher percentage of the ground types we encounter here in the west, and also that most of the ground is shallow anyway, I have of course found smallish pieces down a bit deeper in certain places where the surface layer has been disturbed or in scraped areas, it has a lot to do with layers of ground mineralisation, soil moisture content, temperature of the ground, all these things can play a role as well.

Some areas are quickly worked out of the easy pieces as the nugget responses are very good and very easily heard, but some spots will definitely hide some better nuggets that are not particularly deep, one patch 4-5 nice solid pieces were found and they were all over the ounce mark, but they were only at about maybe the 200 mm depth and from the surface the signals were all very vague, it was not until the surface layer was broken did the signal improve slightly, I was surprised at the sizes of the nuggets and from past finds in that general area would have expected them to give a really good response, just that one particular spot obviously had more going on in the ground.

cheers

stayyerAU
 

Latest posts

Top