Gold in oz

Why is the gold in oz so shallow?
I am in alaska and the gold is deep

In some areas, the gold is shallow, alluvial being the shallowest in most cases.
But there is also a lot of deep gold here as well.
The areas that have deep reefs around my area, also has a lot of fault iines around. I guess that over time, some of the reef stuff gets pushed to or near the surface and moves with the folds in the ground and weather. So I look for shallow ground near deep reefs, some times it works for me,some times it doesn't.

Sourdough Moe said:

Why is the gold in oz so shallow?
I am in alaska and the gold is deep

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You have massive amounts of water compared to us sourdough,yours is well sorted,our gold in arid or outback areas mostly hasnt travelled too far,water action is the difference,id love to get to alaska one day,looks awsome!

Have a gander at The Finders Golden Pages archives, to see what it used to be like.
http://www.finders.com.au/Finders_Archives/News/news.htm

The richest goldfields in Australia were argueably Ballarat and Bendigo. Ballarat had Bakery Hill where the Welcome nugget (2217 ozs) in 1858 was found at 180 feet depth.Then the biggest nugget ever found and 99.5% pure.The first two men who found the monster fainted and were believed dead. There were lots of shallow gullies and Kitty,s Lead was the richest with very large and frequent nuggets from 6 inches to 6 feet depth. The deep leads kept the miners occupied for wages by the companies which were floated and listed on the Melbourne and London stock Exchanges. Some these companies were still operating 30 years after the initial discovery.It is estimated they only got half of the gold in the deeper leads due to flooding. My house is sitting on top of the Sebastopol Lead and I only need to dig a shaft in my back yard if I was young enough. I remember going to Maryborough in 1958 in a Ford Prefect and along the High Street there was lots of mines still operating with huge mullock heaps everywhere. My step father worked at the Wattle Gully Mine in Chewton as a blaster and after heavy rains would hop on his bicycle and go panning in the gullies.

oldtimerROB said:

The richest goldfields in Australia were argueably Ballarat and Bendigo. Ballarat had Bakery Hill where the Welcome nugget (2217 ozs) in 1858 was found at 180 feet depth.Then the biggest nugget ever found and 99.5% pure. There were lots of shallow gullies and Kitty,s Lead was the richest with very large and frequent nuggets from 6 inches to 6 feet depth. The deep leads kept the miners occupied for wages by the companies which were floated and listed on the Melbourne and London stock Exchanges. Some these companies were still operating 30 years after the initial discovery.It is estimated they only got half of the gold in the deeper leads due to flooding. My house is sitting on top of the Sebastopol Lead and I only need to dig a shaft in my back yard if I was young enough. I remember going to Maryborough in 1958 in a Ford Prefect and along the High Street there was lots of mines still operating with huge mullock heaps everywhere. My step father worked at the Wattle Gully Mine in Chewton as a blaster and after heavy rains would hop on his bicycle and go panning in the gullies.

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I looked into this and found that the "largest" nugget size issue is largely mythology, although we might win on number - comparable size nuggets have been found in the Urals and California. Also lumps attached to quartz were commonly termed "specimens" and are commonly excluded from comparison with "nuggets" which helps the Welcome Strangers image (in fact the discoverers trimmed something like 52 lb of quartz off the Welcome Stranger - I think Holtermanns nugget at Hill End NSW was nearly 80% larger even after they broke it up to get it up the shaft). "Richest" depends on whether one means amount of gold or grade of ore. At one time Bendigo was the largest Australian production and Bendigo second (and 11th largest in the world). These figures were true in about 1980 but they have long been overtaken. but what the hell, we love icons and who worries too much about facts ;-). The highest grade mines in Australia last quarter were Fosterville and Costerfield, both in Victoria.
'

Goldchaser1 said:

Sourdough Moe said:

Why is the gold in oz so shallow?
I am in alaska and the gold is deep

Click to expand...

You have massive amounts of water compared to us sourdough,yours is well sorted,our gold in arid or outback areas mostly hasnt travelled too far,water action is the difference,id love to get to alaska one day,looks awsome!

Click to expand...

It is interesting that this is not strictly true, something geologists have only realised in the last couple of decades. Most Australian placer gold was not produced from modern streams but from older, buried valley gravels (not just the "deep leads", deeper than 30 m, but most of the shallow leads as well). When most Australian gold placers were formed all of southern and central Australia was quite wet - trees grew as far north as Broken Hill that are now largely confined to Tasmania (logs and leaves of them are found with the gold). Crocodiles swam in northern South Australia. In now-dry outback areas the factor was probably more lack of topographic relief than amount of water (most of that latest drying has been since humans were on Earth, central Australia had roaring rivers). You can see some evidence of this at Lake Mungo in NSW, now a dry salt lake, where there are huge middens of shells and fish bones from 45,000 years ago when Mungo Man and his mates lived there in wet comfort.

I have worked a bit in Canada and North America, and I suspect that the depth ranges were no different there than here, but much of the shallow stuff of the Alaska and the Yukon has long been worked out (like here). But near-surface nuggets, shallow alluvials and even beach gravel deposits were important there.

Nuggets were smaller and less abundant:

http://www.akmining.biz/mine/nuggets.htm

The biggest nugget found in Russia was only 30 KG, about half of the Welcome nugget. I am trusting my wife who is a Russian historian on this.Any gold finds had to and still are taxable,so not all prospectors registered their finds. Tibet was another rich source of nuggets in the past but very little is known about the largest nuggets due to its isolation. The Welcome nugget was truly a marvel and was on exhibition at the Crystal Palace in 1859.Some large nuggets were also found in the Eastern US by memory.

The Great Triangle nugget found in 1842 in the Urals is still in existence and is on display in the Kremlin and is 33 kg. of fine gold and second largest nugget ever found still in existence. The Hand of Faith is the third biggest at 27.7 kg. The biggest is one from Brazil at 61 kg. found in 1983 and still in existence.
Got some interesting figures and since 2016 China produced 464 tons of gold,Australia 287 and Russia 274.
The Wall of Gold or Holterman nugget from Hill End NSW was not a nugget but a reef matrix or mother lode. It was the largest piece of matrix gold ever found at 285 kg. and contained 142 kg. of gold and was 149 cm long.A 1.84 kg. nugget was found in Tibet in 2010 and this region has probably helped China,s gold production.

I guess a name is a name - one persons nugget is another persons lump of gold, and the interest to me is more how big can a lump grow (as mentioned, there was a huge amount of quartz attached to the Welcome Stranger, which had only slid 20 m or so from its reef source, so the use of
"nugget" is a little academic to me. I have records from the 1800s that indicate nuggets in the greater than 70 kg range from the Urals and from California, and although compiled by a geologist who knows? The Welcome nugget from Ballarat was 69 kg. The largest commonly listed for California is the Fricot nugget at 50 kg. The Canaa nugget from Brazil was 52 kg (I am quoted gold content after smelting) . The Lady Hotham from Ballarat was 45 kg and three other large ones came from the (Canadian )gully where it was found- 61, 42 and 38 kg. The Heron at Castlemaine was 31 kg. Those that are waterworn are usually free of quartz but quartz and breaking up during its removal can account for some discrepancies (as can the issue of smelted gold). So yes, Victoria was a great source of nuggets and still is.

China produced 455 tonnes in 2016 alone and has been the largest producer for some years. In 2017 it was 440, Australia 300, Russia 255 and USA 245, the biggest change in recent years being Russia starting to exceed the USA.

Other large Victorian nuggets were the Blanche Barkly 54 kg, the Precious 53 kg and the Viscount Canterbury 34 kg - two others this size may be the other two from Canadian Gully. The Welcome mentioned above is not the Welcome Stranger of course (it was Moliagul).

There are records of 25kg nuggets from the Margret diggings area, and the source was never found.
Also some large bugs from the pine creek area.

The OP asked "why is the gold in oz so shallow?"
I believe he is referring to alluvial/eluvial deposits as against deep lead/hard rock mining.

In this case the answer is that due to ancient weathering of much of the Australian topography in regions which supported gold formation, such gold released is now resting within a shallow and fragile soil environment close to the country bedrock.

Deep leads exist where weathering of the topography has filled deep ravines with gravels containing gold percentages.
Many ancient gold containing river systems are now through other processes cemented into conglomerates.

I understand that in geologically ancient times the present topography of Hill End (NSW) was around 5km. further above sea level.
By comparison, the sandstone sedimentary deposits of the Surat and Eromanga basins are around 5km. thick with oil and gas reserves at that depth.
Along the Eastern seaboard the ancient volcanics have weathered and eroded to leave extensive sapphire and other heavy mineral deposits in the present day creek and beach systems

All about weathering and transportation of the environment over eons in time.
Its an interesting island upon which we exist.
Mike

Perhaps if he clarified the question - I don't think that there is a lot of difference in depth except with regards to eluvial gold (and whether one is comparing with inland Australia rather than the east coast). Victoria and Western Australia are as different as Alaska and Western Australia with respect to gold, largely a function of topography (eg with little relief a lot of Western Australian eluvial gold has not been washed into streams). I don't think we are saying different things Boobook. Most Victorian alluvial gold was not at surface but was Cenozoic (it did not come out of modern flowing streams in the main) - one reason it probably was not discovered earlier. Deep leads are not different to shallow leads, it is a continuum - the term deep lead relates only to where the same leads became deeper than about 30 m (this required pumping, heavy machinery and syndicates and companies, so there was a pause in time of a decade or more before mining went to these greater depths). I'm a bit doubtful about Hill End being a further 5000 m above sea level than at present (1000 m), but it is conceivable, and it certainly was higher (estimates for central Victoria highlands is that much less than 2000 m has been stripped since the Cenozoic leads formed - in fact only 2000 m since about the Cretaceous, prior to the leads forming based on fission track work). My guess is typically less than a kilometre since most leads formed here.

Wow a lot of information Thanks guys for all the answers very much appreciated

As a boy I was enthralled by the exploits of the British explorer Percy Fawcett who was commissioned by the Bolivian government in 1906 to survey and delineate the boundaries of Bolivia which were then not fixed. He was tasked also to explore for gold,silver and diamond deposits in the Bolivian Andes and also to do surveys and cost estimates for possible routes of railway lines. He was in later life always looking for the lost city of Eldorado in the Brazilian jungle after reading an eye witness account of the Spanish Conquistadors who had seen it and described its roofs of gold glistening in the sun.He and his two sons were killed in the Xingu area of Brazil by hostile Indians.He was a romantic adventurer and my boyhood hero.So is it the quest and the journey in the search for gold or the gold itself that is more important? It is a riddle which may never be solved as a man fired up with the spirit of adventure is already rich beyond measure.Who knows how much gold and large nuggets were found in the Andes and it was a very rich source of gold and silver judging by how many Spanish galleons were transporting it back to Spain.Also Emeralds,rubies and diamonds were found.It could have been so rich as to rival the Victorian goldfields found a few hundred years later.

oldtimerROB said:

As a boy I was enthralled by the exploits of the British explorer Percy Fawcett who was commissioned by the Bolivian government in 1906 to survey and delineate the boundaries of Bolivia which were then not fixed. He was tasked also to explore for gold,silver and diamond deposits in the Bolivian Andes and also to do surveys and cost estimates for possible routes of railway lines. He was in later life always looking for the lost city of Eldorado in the Brazilian jungle after reading an eye witness account of the Spanish Conquistadors who had seen it and described its roofs of gold glistening in the sun.He and his two sons were killed in the Xingu area of Brazil by hostile Indians.He was a romantic adventurer and my boyhood hero.So is it the quest and the journey in the search for gold or the gold itself that is more important? It is a riddle which may never be solved as a man fired up with the spirit of adventure is already rich beyond measure.Who knows how much gold and large nuggets were found in the Andes and it was a very rich source of gold and silver judging by how many Spanish galleons were transporting it back to Spain.Also Emeralds,rubies and diamonds were found.It could have been so rich as to rival the Victorian goldfields found a few hundred years later.

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It still is rich and producing gold....