Australia, a big country!! What fraction has been detected?

[Teemore]

A recent post by Zakman highlighted the fact that an area that was just detected without success, was detected by someone else and bingo ...... Nugget!!

Leads me to ask just how much of an area is covered when detecting, not just the area physically walked over but the actual area covered by the coil at different depths.

Something for the maths experts to determine but if as an example a 15inch coil detects a 15 inch circle at 1 inch depth, a (say) 10 inch circle at 9inch depth and (say) 3 inches at 12 inch depth and a sweep is 2 yards wide how much area is really covered in an hours detecting?

One step too big and you miss an overlap, leaving the prize so the next bloke. The question, apart from the fact I'm bored at work this morning , is really how many square yards (meters) are covered in an average hours detecting.

Hope some of that makes sense.
Cheers Tom

 

[G0lddigg@]

thats a tricky one, how many trees did I have to go around, how many targets did i dig did i have to rake etc etc. I enjoy walking the rows in pine forests it gives me a good sense of covering the whole area. I might work two hours in a session probably would only cover 600 square meters

 

[nuggetino]

Very interesting. It will be impossible to give anything but a theoretical answer to your question but I'm no mathematician. I'd thought about this myself especially after finding and nice 2 gram nugget in an area that's been gone over by hundreds if not thousands of people over the years.

I figure most people don't precisely match their coil overlaps, not to mention in less open terrain they'd find themselves lifting their coil over debris, grasses, stones and maneuvering between trees effectively interrupting their sweep pattern and limiting coverage.

There are natural causes too which will effect the productivity of a patch. Erosion by wind and rain is going to expose gold in areas frequently detected over. Also, areas where vegetation is present are constantly changing. Trees growing, roots pushing up soil and potentially gold. Vegetation dieing off revealing patches of ground no coil has seen.

Let's just say someone should undertake the tedious task to accurately scan every last square foot of a given patch with one coil. Well they'd have to go back and do it again with a larger, smaller coil of both DD and MONO type not to mention run optimal settings for each coil for that given patch if they wanted to get every single last bit of detectable gold.

That's assuming the person is in the zone at all the time and does not miss any faint signals another prospector may hear. So many variables and such an enormously time consuming task on even a small patch.

I guess this is the reason you can go over a patch that's been hammered for years and still come home with gold.

 

[loamer]

Nuggetino - spot on advice. Finding the start for a patch is just step one. There is the gridding, detecting, removal of ground cover, coil changes, possibly detector changes, and re-crossing the patch at different angles. The re-visits to worked areas aftre some years has proven most profitable with the newer detectors and coils. Areas that I hit with my 2200 with a DD, I am now rescanning with a 4500 with a mono. In most cases the gold is smaller but not necessarily deeper.

Its the old line thrown in our faces a lot "You have secret spots that have gold and won't tell anyone." No - I have spots that HAD gold and I know there is still gold that current technology can't quite 'hear/see'.

I have an area that has proven very profitable - about a 10 x 10 m2 area in a huge piece of virgin ground. I thought I had it all but revisited recently with a 25" coil and got the faintest of whispers quite deep in the same area. the result was a couple of nice pieces. All the gold in this area is in situ - that is still in the quartz matrix. The indicators have been rotted mineralised surface quartz, ironstone and blueish/greenish slates. running in a north south direction, slight slope that has a defined flat spot. The point is, I have spent hours/days in this area alone. In total, 100m2. The total area that looks the goods is about a 250m x 250m area. this will take years to detect properly. The reason the old blokes missed it still has me puzzled but the continued finds in Victoria shows they did not get it all. Look at the Hand of Faith nugget and the recent big find at Ballarat. All gives us hope!