Do puddlers provide useful information for gold detecting (probably not)?

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A member recently posted the comment "puddlers are a huge bonus to an amateur prospector because they indicate regions where the gold was trapped in clay and was difficult to wash, so the chances of finding a piece or two around those particular gullies is probably pretty high"

I feel that there is a misconception here (and not only because I see puddlers all over the place). Water sorts material according to size and density (the mass of grains - so water will concentrate coarse gold, nuggets, ironstone, dense gems like sapphire and diamonds etc within coarse, gravelly wash, especially towards its base, and not with clay - for clay to settle out of water directly very low flow velocities are required, and coarse gold will have already been dumped before such slow velocities are reached). Gold nuggets are as different in density and mass to clay as one can get. Some nuggets in clay formed in the clay of soils in laterite profiles, as in Western Australia, but that is not common in southeastern Australia (where we mostly see puddlers). However puddlers were used to get gold out of clay in alluvial gold leads in the main. I question "they indicate regions where the gold was trapped in clay and was difficult to wash" - instead they indicate a device used to separate from the clay component of gold-bearing alluvials (not usually a 'region", but "one component" of the wash).

So why do nuggets often occur in clay in alluvial gold deposits? Because it is commonly not alluvial clay but decomposed bedrock beneath gravelly wash.

One needs to look at how gold occurs in wash to understand why it occurs in clay. Most gold including nuggets occurs in a gravel layer that overlies weathered bedrock. However being heavy and concentrated towards the base of deposits, coarse gold including nuggets will penetrate downwards to some depth in cracks in clay bedrock. The miners would commonly sluice the easily separated gold from the overlying quartz gravel but treat the underlying clay (decomposed but in situ bedrock) separately. The nuggets are in clay, but it is commonly not alluvial clay but decomposed bedrock that is still in situ.

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"Placer gold was mostly produced from within 2 m of the unconformity between the gravel and underlying Paleozoic rocks (Hunter, 1909). The basal gravels were typically 0.15 to 1 m thick, with thicknesses as great as 10 m being very rare.......... Commonly, decimeters of the top of the Paleozoic bedrock were also mined because of the presence of gold in mechanical traps". Up to a third of the alluvial gold production was recovered from this weathered bedrock below the gravel.

Commonly the "sticky" clay of this bedrock could not be sluiced like the gravel overlying it but was scraped up separately after shoveling off the gravel. It was treated separately in puddlers. So the presence of puddlers commonly only indicates devices used to treat the basal part of the alluvials in any area, and do not indicate some special nature of the alluvials in an area. Some areas did lack the decomposed bedrock clay base, with the gravels resting on fresh bedrock, but this was more common in the highlands where nuggets are relatively rare (and one only has to use ones eyes to see the different nature of bedrock). The common situation throughout the goldfields of central Victoria for example, where most Victorian nuggets come from, is that the puddlers were simply treating the sticky decomposed clay bedrock at the base of MOST alluvial gravels in MOST goldfields. As such, I would not consider puddlers usually to be a useful indicator of areas or regions for detecting, any more than any alluvial workings in such an area are indicators.
 
Just to add some of my thoughts here as well, is that I have seen puddlers located in gullies where there have been no gold workings at all.
The reason for their location was a good catchment for water and the old diggers would have had to cart their washdirt some distance from other diggings to have it processed. This would suggest that the washdirt would have had to have been quite rich as one would expect coming from the bottom of holes. Carting large quantities of low grade elluvial deposits to treat would have been very expensive for the old times.
I believe also that possibly some puddlers were built and operated communally or for a fee and were located not necessarily to treat gold from the gully where they were located but because they were central to the diggers they serviced.
 
Just to add some of my thoughts here as well, is that I have seen puddlers located in gullies where there have been no gold workings at all.
The reason for their location was a good catchment for water and the old diggers would have had to cart their washdirt some distance from other diggings to have it processed. This would suggest that the washdirt would have had to have been quite rich as one would expect coming from the bottom of holes. Carting large quantities of low grade elluvial deposits to treat would have been very expensive for the old times.
I believe also that possibly some puddlers were built and operated communally or for a fee and were located not necessarily to treat gold from the gully where they were located but because they were central to the diggers they serviced.
I agree completely on these points but felt that I did not want to obscure the main point I was making with too much detail. Washdirt was commonly quite rich so transport was not necessarily always an issue.

"Stories from individual mining centers told of fabulous riches during this period of placer mining (Hughes and Phillips, 2001). The 3 km stretch of Forest Creek and its tributaries at Castlemaine produced 80 t of gold in the first 10 years, peaking at 3 t of gold per week. Nearby at Donkey Gully, it is claimed a tonne of nuggets was picked from the surface. There are several reports from other locations of nuggets lying on the ground “like potatoes,” or of prospectors using shovels to turn over the gravel and pick out the nuggets. At Ballarat, a 3 × 3 m placer claim yielded a total of 430 kg of gold. Even 55 years after the initial rush, at Poseidon near Tarnagulla, a single 25-m claim yielded five 10 to 30 kg nuggets, and an additional 100 kg of finer gold. Nuggets of many kilograms are still found (e.g., the 23 kg Hand of Faith found at Wedderburn in 1980)."
Typical average grades are more relevant to what we are discussing but were also high "Typical grades of the larger Victorian placers ranged from 5 to 40 g/m3, averaging approximately 10 g/m3 (Canavan, 1988)" A miner needed about an ounce per week "to get by", so needed to treat less than a cubic metre up to 6 cubic metres per week, typically 3 cubic metres.
 
Great thread.

Im always impressed how you can remember and quote such details Goldirocks. Thanks.

I had more thoughts of a personal nature but wont clog the thread.
 
I agree completely on these points but felt that I did not want to obscure the main point I was making with too much detail. Washdirt was commonly quite rich so transport was not necessarily always an issue.

"Stories from individual mining centers told of fabulous riches during this period of placer mining (Hughes and Phillips, 2001). The 3 km stretch of Forest Creek and its tributaries at Castlemaine produced 80 t of gold in the first 10 years, peaking at 3 t of gold per week. Nearby at Donkey Gully, it is claimed a tonne of nuggets was picked from the surface. There are several reports from other locations of nuggets lying on the ground “like potatoes,” or of prospectors using shovels to turn over the gravel and pick out the nuggets. At Ballarat, a 3 × 3 m placer claim yielded a total of 430 kg of gold. Even 55 years after the initial rush, at Poseidon near Tarnagulla, a single 25-m claim yielded five 10 to 30 kg nuggets, and an additional 100 kg of finer gold. Nuggets of many kilograms are still found (e.g., the 23 kg Hand of Faith found at Wedderburn in 1980)."
Typical average grades are more relevant to what we are discussing but were also high "Typical grades of the larger Victorian placers ranged from 5 to 40 g/m3, averaging approximately 10 g/m3 (Canavan, 1988)" A miner needed about an ounce per week "to get by", so needed to treat less than a cubic metre up to 6 cubic metres per week, typically 3 cubic metres.
There was gold in clay at Hill End in NSW. Several buildings were built using bricks made from the local claypits. When it was realised that the bricks contained clay some old houses were demolished and the bricks crushed and panned. The results apparently justified the effort.
The path into the Hill End museum is made of local bricks and one rainy day, when the dust had been washed off the path, we saw several nice slugs of gold on the faces of some of the bricks. How much more was hidden within the bricks it is impossible to say but it was easy to see why the old-timers crushed bricks and panned the result.
 
I agree completely on these points but felt that I did not want to obscure the main point I was making with too much detail. Washdirt was commonly quite rich so transport was not necessarily always an issue.

"Stories from individual mining centers told of fabulous riches during this period of placer mining (Hughes and Phillips, 2001). The 3 km stretch of Forest Creek and its tributaries at Castlemaine produced 80 t of gold in the first 10 years, peaking at 3 t of gold per week. Nearby at Donkey Gully, it is claimed a tonne of nuggets was picked from the surface. There are several reports from other locations of nuggets lying on the ground “like potatoes,” or of prospectors using shovels to turn over the gravel and pick out the nuggets. At Ballarat, a 3 × 3 m placer claim yielded a total of 430 kg of gold. Even 55 years after the initial rush, at Poseidon near Tarnagulla, a single 25-m claim yielded five 10 to 30 kg nuggets, and an additional 100 kg of finer gold. Nuggets of many kilograms are still found (e.g., the 23 kg Hand of Faith found at Wedderburn in 1980)."
Typical average grades are more relevant to what we are discussing but were also high "Typical grades of the larger Victorian placers ranged from 5 to 40 g/m3, averaging approximately 10 g/m3 (Canavan, 1988)" A miner needed about an ounce per week "to get by", so needed to treat less than a cubic metre up to 6 cubic metres per week, typically 3 cubic metres.
I have 2 creeks that I frequent and one, in particular, was so rich that according to surviving reports, the ol' timers only bothered to collect the "tolerably large pieces" which i reckon would be what we nowadays call "pickers" - as for the remainder, it was simply tipped back into stream for us to find today.
 
I have 2 creeks that I frequent and one, in particular, was so rich that according to surviving reports, the ol' timers only bothered to collect the "tolerably large pieces" which i reckon would be what we nowadays call "pickers" - as for the remainder, it was simply tipped back into stream for us to find today.
Most fields were worked many times, and we have had two major depressions during which alluvial gold deposits were re-worked - the Chinese diggers were especially efficient after the Europeans left a field. But of course there is always a bit that everyone missed.....
 

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