How to assess ground for Gold

[Coopes]

Hi Team,
This in sort of gets me, so when testing ground some guys can test the amount of colours in the the pan to how much Gold per tonne they can.

Can any one teach me this formula would be so greatly appreciated

Coopes :|

 

[grubstake]

I believe the skill you're interested in is called 'loaming'. A search with the magnifier icon above will find you more, but this post by Deepseeker gives a good brief introduction:
https://www.prospectingaustralia.com/forum/viewtopic.php?id=33284

In Australia and the US, such ground sampling has been used to track down reefs in virgin ground. There's an old Aussie book called "Loaming" by Sam Cash, that's regarded as the bible on the technique.

One of the US gold prospecting TV shows features a "legendary prospector" who uses a gold pan to test alluvial ground before bulk mining and regards a representative panned sample as definitive evidence of likely ounces per ton. From his success rate on the show, I'm not entirely convinced that he really knows what he's doing, although he makes it look very scientific on camera.

 

[Coopes]

Thanks so much, greatly appreciated ?

 

[user 4386]

It can only be done for a particular area, once you have experience of the area. Problem is that gold grain size varies so much from area to area.
Loaming is used to trace gold in soil (eg up a hillside) to find its source. Not so much an estimation tool - more a case of being on gold or not on gold. A crude and ancient method but it does work.
The only accurate method of estimation is assaying, and even its accuracy depends on a proper sampling technique being used.

 

[mudgee hunter]

if you fill us in a bit more in depth, you might get more accurate replies of what you want.
Say if your crevicing in a creek your yield per tonn will be very high per say, compared to a random spot on the creek.
But slower to recover.
Don't ever be shy to ask!
Starting has a million questions....
No one is a 100% guru!

 

[jethro]

I have tried sampling right below known reef deposit where they outcropped but have yet to see even a small colour in the pan. the only way I have found primary deposits was by chip sampling outcrops and or drilling into them.

 

[user 4386]

I have tried sampling right below known reef deposit where they outcropped but have yet to see even a small colour in the pan. the only way I have found primary deposits was by chip sampling outcrops and or drilling into them.

I find that is common with quartz vein gold deposits where the gold is fairly coarse (eg at Bendigo the AVERAGE size of gold grains is millimetres). However where gold is fine, or when gold is fine and locked inside grains of sulphide (eg pyrite) which are oxidising, often in wall-rock adjacent to the quartz vein or where there is no single pronounced quartz vein, then you will see it in the soil. Really a function of grain size and grade - a few of those miilimetre gold grains gives ore-grade quartz, but a great many pin-head and smaller grains are required to give the same grade, and they will more often appear in your loam sample.

 

[Jemba]

Hi Team,
This in sort of gets me, so when testing ground some guys can test the amount of colours in the the pan to how much Gold per tonne they can. Can any one teach me this formula would be so greatly appreciated. Coopes

Coopes what a good question to put forward. There really is quite a lot of different answers to that question it all gets back to experience and the type of prospecting you wish to do. If by chance you can link up with a person who dose the type of prospecting you wish to do then do so, it is the best way to learn. But as a broad guide I will post a section of a report from the late Professor of Geology school of mines Golden city, Colorado USA. I hope it is of a help to you.

https://babel.hathitrust.org/cgi/pt?id=uc1.aa0013054978&view=1up&seq=120

 

[Anniegee]

Thanks for posting that article Jemba....very interesting

 

[user 4386]

Hmmm- he is a very late Professor (about 114 years - although it is basically correct). Seriously though, people did not stop mining placers a century ago, nor did they stop writing about them, and geology has come a long way since. I notice a tendency on this site to treat gold placers as something of the past, because our gold rushes were then. Placer mining continues today, and a few ideas have changed.

https://www.911metallurgist.com/prospecting-placer-gold-deposits/#Placer-Mining

https://www.911metallurgist.com/gold-placer-prospecting/

https://nbprospecting.wixsite.com/nbprospecting/gold-prospecting-panning-tips

https://bcgoldadventures.com/sluice-building-for-fine-gold-recovery-part-1/

http://www.goldprospectingonline.co...a-beach/how-and-where-find-beach-placer-gold/

https://jgs.lyellcollection.org/content/142/5/725

 

[Jemba]

Hmmm- he is a very late Professor (about 114 years - although it is basically correct). Seriously though, people did not stop mining placers a century ago, nor did they stop writing about them, and geology has come a long way since. I notice a tendency on this site to treat gold placers as something of the past, because our gold rushes were then. Placer mining continues today, and a few ideas have changed.

https://www.911metallurgist.com/prospecting-placer-gold-deposits/#Placer-Mining

https://www.911metallurgist.com/gold-placer-prospecting/

https://nbprospecting.wixsite.com/nbprospecting/gold-prospecting-panning-tips

https://bcgoldadventures.com/sluice-building-for-fine-gold-recovery-part-1/

http://www.goldprospectingonline.co...a-beach/how-and-where-find-beach-placer-gold/

https://jgs.lyellcollection.org/content/142/5/725

Top post mate thanks. :Y:

 

[user 4386]

The old description is fairly good in its detail, but can be confusing because of outmoded terminology. For example you will see it referring to "reef rock" which it says is slate. Most prospectors today confine the term "reef" to quartz reefs, but in those days reef was any hard band of rock (a "bar"). It is correct about waterfall areas rarely being productive (the opposite of what one might think), and in emphasing the importance of gold in crevices and potholes extending into bedrock below the "lead" (up to a third of production came from these, two-thirds from overlying gravel etc.). Note that "deep lead" is then and sometimes nowadays used for deep aquifers (water), not just gold, although it is an unscientific term - seems to be synonomous with a buried channel. "Drift" or "float" was often used for young non-alluvial material (eg soil and rock that had moved downslope under gravity and spread out to bury a "lead"- hillwash etc.). A "deep lead" was typically deeper than 30 m (distinction from a shallow lead often being that companies or syndicates often had to form to purchase more expensive pumps and winding gear to work at greater depths, on some fields causing a pause of up to years (e.g. initially it might be said that "it was worked until the water got too bad", when in fact it only awaited decent pumps). Few mines were ever stopped ultimately because of water, but "deep leads" often required more than a year of pumping before they could be worked. Deaths due to inflow of water stopped some mines (i.e. the death toll rather than the volume of water stopping mining). Death tolls could be horrendous, averaging one man per day for many months on some fields - so be wary if you try primitive mining methods at depth. "Leader" quartz veins usually just meant thin veins with gold - not veins wide enough to stope in hard rock. Many people on this site have misunderstood this term as some sort of indicator of gold, when the old miners simply used it in the sense that it might be a branch off a wider vein, so might be worth following to find a bigger vein nearby (size being more the issue). See photos

;

A better view giving reference details - good for beginners:

Hope that helps a bit...learn some geology and increase your chances a hundredfold.......

 

[Jemba]

Spot on the money, I totally agree with what you have stated. :Y: