Hunting for "REEF" Gold....an approach for beginners.

[user 4386]

Hi - I don't think I have ever posted here because it always seems good, accurate advice. Just one comment though on "Don't spend much time around "White" quartz outcrops which have no visible signs of mineralization...they are nearly always devoid of gold". Most major central Victorian gold reefs look just like that - big bucky quartz reefs - because the gold is often in the finely laminated margins (this photo from Fiddler's reef Percydale illustrates an example - little gold in the white quartz because it is associated with the thin layers of dark rock within it at its margins). These also tend to have more sulphides in them and readily break up and weather away leaving the big white quartz body sticking out of the ground. But the gold can be there, on the margins, in the soil now. More the rule rather than the exception.

 

[WalnLiz]

Hi - I don't think I have ever posted here because it always seems good, accurate advice. Just one comment though on "Don't spend much time around "White" quartz outcrops which have no visible signs of mineralization...they are nearly always devoid of gold". Most major central Victorian gold reefs look just like that - big bucky quartz reefs - because the gold is often in the finely laminated margins (this photo from Fiddler's reef Percydale illustrates an example - little gold in the white quartz because it is associated with the thin layers of dark rock within it at its margins). These also tend to have more sulphides in them and readily break up and weather away leaving the big white quartz body sticking out of the ground. But the gold can be there, on the margins, in the soil now. More the rule rather than the exception.


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Been waiting for just this kind of reply Goldie...I'm giving advice from personal experience and directing it towards newcomers who are starting out and are not into complex geological terms to confuse them with "what else can be found" within quarts "blow outs". I have hundreds of gold species within "pure white " quartz and "Yes", It does occur microscopically within "Some" of the thin dark layers, but for the purpose of "detectable gold", you are wasting a lot of time on this type of quartz if that's all you are following. There is hundreds of quartz blow outs within both gold and non gold fields. An extremely small amount of surface quartz has "Visible" gold in it beneficial to the detector operator and this is what we are chasing.

I could easily just "cut and paste", with pictures and technical information as many do, but that would not be what I'm trying to get across to the operators I'm directing this thread at. I prefer to use the "KISS" principal, and leave the technical side to the reader who wants to expand his "Technical" knowledge by doing their own research. I'm not trying to give a "Geological" lesson in this thread, but advice on how best to "detect reef gold"..... Cheers Wal.

 

[Simmo]

You guys might remember my posts about my days out with Iain Aitken and Doug Stone at Arltunga.??
We found over ten ounces in 3 days on a flat, below a big quartz blow.
The quartz and the whole of the flat was as white as snow.
Same thing if you go to Western Creek, keep an eye out for that quartz and detect around there.
What is down hill now, may not have been down hill then, so think outside the square!!

 

[WalnLiz]

You guys might remember my posts about my days out with Iain Aitken and Doug Stone at Arltunga.??
We found over ten ounces in 3 days on a flat, below a big quartz blow.
The quartz and the whole of the flat was as white as snow.
Same thing if you go to Western Creek, keep and eye out for that quartz and detect around there.
What is down hill now, may not have been down hill then, so think outside the square!!

Exactly right Simmo and I would imagine many species would have been amongst that lot. Same goes for Tibo and they are the visible gold stringers we are looking for. Most of these areas have kilometres of fractured quartz in the region but finding the ones which had detectable gold are the challenge.

 

[user 4386]

Been waiting for just this kind of reply Goldie...I'm giving advice from personal experience and directing it towards newcomers who are starting out and are not into complex geological terms to confuse them with "what else can be found" within quarts "blow outs". I have hundreds of gold species within "pure white " quartz and "Yes", It does occur microscopically within "Some" of the thin dark layers, but for the purpose of "detectable gold", you are wasting a lot of time on this type of quartz if that's all you are following. There is hundreds of quartz blow outs within both gold and non gold fields. An extremely small amount of surface quartz has "Visible" gold in it beneficial to the detector operator and this is what we are chasing.

I could easily just "cut and paste", with pictures and technical information as many do, but that would not be what I'm trying to get across to the operators I'm directing this thread at. I prefer to use the "KISS" principal, and leave the technical side to the reader who wants to expand his "Technical" knowledge by doing their own research. I'm not trying to give a "Geological" lesson in this thread, but advice on how best to "detect reef gold"..... Cheers Wal.

I was just pointing out the opposite - that big quartz blows without gold in the massive quartz are the main ore bodies on the central Victorian goldfield and contain coarse gold associated with the interlayered slate, usually on their margins, This is what the miners called "magpie quartz" because they knew it was an indicator of good gold. Most lodes on the major fields that provided most of the gold in quartz veins was of this type - Bendigo, Ballarat, Stawell, Daylesford, Chewton, Maldon, Yandoit etc. (I could give the names of individual mines but it is most of them). I don't disagree with your observation that the massive quartz itself is poor in gold, but that does not mean that these massive blows lack gold on their margins - it is just not in the massive white quartz itself but is their margins etc that provided most of the gold. For example, nuggets over 15 kg at Ballarat, of which there were a number, all came from big quartz blow systems (immediately downslope as a rule, as you correctly point out). We see it not only underground but when we drill through them, and I have seen plenty of coarse gold and nuggets from soil adjacent to them. Not a theoretical geological lesson but direct visual observation and from detecting.

Of course most quartz veins and blows of any type lack interesting gold, but that is not the same as blows lacking gold compared with anything else (non-blows)- those big quartz bodies provided most of the reef gold of central Victoria. Conversely, a lot of fields with miserable little veinlets are quite good for detecting even though they provided only a tiny part of total Victorian production - you will note that places like Moliagul, Dunolly etc that were rich in alluvial and nuggets do not appear in the names above that I mention (the fact that they were often left alone by companies probably increases their prospectivity for metal detecting now). Speculating there...

And the photo I posted is not just cut and paste from the literature (more the opposite, and a site I observed).

As I said, this is the only thing that I have seen you write that I have really slightly disagreed with - I think what you write is very accurate and pitched at just the right level.

 

[WalnLiz]

I was just pointing out the opposite - that big quartz blows without gold in the massive quartz are the main ore bodies on the central Victorian goldfield and contain coarse gold associated with the interlayered slate, usually on their margins, This is what the miners called "magpie quartz" because they knew it was an indicator of good gold. Most lodes on the major fields that provided most of the gold in quartz veins was of this type - Bendigo, Ballarat, Stawell, Daylesford, Chewton, Maldon, Yandoit etc. (I could give the names of individual mines but it is most of them). I don't disagree with your observation that the massive quartz itself is poor in gold, but that does not mean that these massive blows lack gold on their margins - it is just not in the massive white quartz itself but is their margins etc that provided most of the gold. For example, nuggets over 15 kg at Ballarat, of which there were a number, all came from big quartz blow systems (immediately downslope as a rule, as you correctly point out). We see it not only underground but when we drill through them, and I have seen plenty of coarse gold and nuggets from soil adjacent to them. Not a theoretical geological lesson but direct visual observation and from detecting.

Of course most quartz veins and blows of any type lack interesting gold, but that is not the same as blows lacking gold compared with anything else (non-blows)- those big quartz bodies provided most of the reef gold of central Victoria. Conversely, a lot of fields with miserable little veinlets are quite good for detecting even though they provided only a tiny part of total Victorian production - you will note that places like Moliagul, Dunolly etc that were rich in alluvial and nuggets do not appear in the names above that I mention (the fact that they were often left alone by companies probably increases their prospectivity for metal detecting now). Speculating there...

And the photo I posted is not just cut and paste from the literature (more the opposite, and a site I observed).

As I said, this is the only thing that I have seen you write that I have really slightly disagreed with - I think what you write is very accurate and pitched at just the right level.

There is not a field in VIC including the high country where I spent over 20 years dredging that I haven't spent countless hours detecting on over the past 55 years. I have come across hundreds of quartz blows exactly the same as the pic you have posted and rarely found an outcrop with detectable gold. I have found more detectable gold in quartz with ironstone staining and associated mineralization.

I was going to write a lengthy response to the one thing you "Slightly Disagree" with, but figure it would only end up with no beneficial input to what I'm trying to get across in the thread, and I don't want to get into a debate over it. Thanks for your informative input and I will leave it at that... Cheers Wal

 

[user 4386]

There is not a field in VIC including the high country where I spent over 20 years dredging that I haven't spent countless hours detecting on over the past 55 years. I have come across hundreds of quartz blows exactly the same as the pic you have posted and rarely found an outcrop with detectable gold. I have found more detectable gold in quartz with ironstone staining and associated mineralization.

I was going to write a lengthy response to the one thing you "Slightly Disagree" with, but figure it would only end up with no beneficial input to what I'm trying to get across in the thread, and I don't want to get into a debate over it. Thanks for your informative input and I will leave it at that... Cheers Wal

Let's agree to disagree - slightly more years for me, so we are both old farts. All major nuggets at Ballarat came from such bodies, I have personally seen up to 400 oz nuggets come out of the margins of big barren-looking quartz blows and know barren-looking quartz blows still cropping out over many metres in width from which 300,000 oz have been extracted, and have much coarse gold detected from the margins of large quartz blows that still outcrop within the Ballarat city limits. My point was that it seems a pity to exclude the vicinity of large quartz blows when detecting, as well as looking at the other places you discuss. Never yet seen anything come out of the middle of a large iron-poor quartz outcrop as you say, so I am not sure to what degree we are disagreeing (hence the "slightly disagree".

 

[WalnLiz]

Let's agree to disagree - slightly more years for me, so we are both old farts. All major nuggets at Ballarat came from such bodies, I have personally seen up to 400 oz nuggets come out of the margins of big barren-looking quartz blows and know barren-looking quartz blows still cropping out over many metres in width from which 300,000 oz have been extracted, and have much coarse gold detected from the margins of large quartz blows that still outcrop within the Ballarat city limits. My point was that it seems a pity to exclude the vicinity of large quartz blows when detecting, as well as looking at the other places you discuss. Never yet seen anything come out of the middle of a large iron-poor quartz outcrop as you say, so I am not sure to what degree we are disagreeing (hence the "slightly disagree".

Old farts for sure Goldie...70 years is at the wrong end of the age bracket for swinging detectors in challenging terrain. I'm not limiting my experience to Ballarat alone and I'm not going from "What I have seen come out" but from what I have "personally" detected. I have plenty of "personal" pics I could post up if that would help. Lets agree to disagree but in saying that "All good this end"....Wal.

 

[user 4386]

Just to explain more clearly - the photo I showed was a working face averaging around 11 g/t gold across it (from a mine that was the source of many alluvial nuggets in the gully that drains it). However , most gold in the quartz is concentrated with sulphides in the more sulphide-rich margins with slate inclusions. The margins weather more readily and the sulphides oxidise in outcrop, so often the big bucky quartz blow is all that is obvious at surface, not the laminated material in contact with the wall-rock, which has disintegrated into the soil.

My point was - certainly don't waste time detecting within the massive white quartz (we agree on that) but try in soil along its margins - assuming that you are within an old goldfield to start with. Another detailed photo of the margin of the face (not mine) may better clarify what I mean. I'll avoid the theory but there is a good chemical reason why the gold and sulphides concentrate with the slate on the margins.



Not from Ballarat or any of the other scores of goldfields that I have worked on (finding one mine that is still working)- I gave Ballarat as an example because of its numerous large nuggets and accurate known locations for them and because it is typical of many central Victorian fields with quartz blows. I agree not warranting further discussion.

 

[Beer Drinker]

I'm only a noob, but people forget the top 20metres of ground has probably been taken off of the ground compared to what we see today in the GT. The old timers would also remove the quartz reefs totally. What we see today, is not a true representation of what was once there.
The ground has been massively changed by man.

 

[user 4386]

I'm only a noob, but people forget the top 20metres of ground has probably been taken off of the ground compared to what we see today in the GT. The old timers would also remove the quartz reefs totally. What we see today, is not a true representation of what was once there.
The ground has been massively changed by man.

I think most people know that it is totally changed (there are plenty of old photos), although 20 m would very rarely be removed (usually a couple of metres at most - if deeper they usually sank shafts). Trouble is, a lot of it has simply been dumped on top of other areas. However this is mostly not a huge issue for recreational detecting and can be a boon in places. Recreational prospectors usually get nowhere near the original gold-bearing gravels that the old-timers worked, except where it is that redistributed material. And on hillsides the soil has often mostly gone, giving more access to bedrock. However it helps if you can interpret how an area has been worked.

 

[WalnLiz]

I'm only a noob, but people forget the top 20metres of ground has probably been taken off of the ground compared to what we see today in the GT. The old timers would also remove the quartz reefs totally. What we see today, is not a true representation of what was once there.
The ground has been massively changed by man.

The ground in "certain" areas is definitely not reflective of what it was over a150 years ago, but most surfacing was to a depth of only a few metres. It was generally chasing shallow alluvial leads where shafting was deemed too dangerous when tunnelling at such shallow depths."20 metres" would be closer to the depth of where the bedrock was for the larger "alluvial" nuggets in most of the Triangles ancient river courses, though in some areas the alluvial was substantially deeper. At this depth surfacing was rarely carried out. This is closer to the depth where shafts and tunnelling was the preferred method on most alluvial fields in the area from which many of the large nuggets were extracted.

What we are trying to determine in this thread is not "alluvial" digging but the type of geology where reefs were worked, and where the now disconnected stringers could possibly be located by mostly electrical loaming. Remember many sections of the disconnected stringers are still not exposed and some still have detectable gold within or shed from them. Stringers can have both exposed sections and sections broken away from early earth movements, especially if folding was associated at that time, giving quite a bit of horizontal separation The deep major reefs had all the gold bearing ore extracted and processed, and the lines of reefs with their many shafts generally offer only the odd bit of detectable gold thrown out with the mullock. The old timers unfortunately were very thorough.

I hope you don't get too discouraged Beer Drinker thinking that too much ground might have been massively changed by man to dampen your spirits in the hunt for reef gold....Wal.

 

[WalnLiz]

I think most people know that it is totally changed (there are plenty of old photos), although 20 m would very rarely be removed (usually a couple of metres at most - if deeper they usually sank shafts). Trouble is, a lot of it has simply been dumped on top of other areas. However this is mostly not a huge issue for recreational detecting and can be a boon in places. Recreational prospectors usually get nowhere near the original gold-bearing gravels that the old-timers worked, except where it is that redistributed material. And on hillsides the soil has often mostly gone, giving more access to bedrock. However it helps if you can interpret how an area has been worked.

Great minds must think alike Goldie ...we posted almost exactly at the same time with almost the same content. Doesn't hurt to have a doubled up perspective hey.

 

[user 4386]

Great minds must think alike Goldie ...we posted almost at the same time with almost the same content. Doesn't hurt to have a doubled up perspective hey.

No, hardly surprising though that two old guys with as many miles under our belts would come up with similar answers.
I have always agreed with your general principle that reef sources beat old alluvial dumps for detecting in the modern era. I see lots of people getting small amounts with lots of work around the collars of old alluvial shafts, but I suspect that is mostly stuff that the old timers passed through slightly above the wash, or spilled at the collar - they tended to be very efficient as to how they kept and treated the wash itself (except in some very shallow and dry diggings). Even without detectors, people would "speck" the dumps, especially after rain, during the 1890 and 1930 depressions (and we still did it as kids). And I think there is still plenty to be found on the hillsides, because they did not chase every tiny quartz veinlet, and because even in Victoria there was often insufficient water to mass-sluice entire hillsides (and that was banned after a few years).

As you would know....

 

[WalnLiz]

I for one am glad water was not that plentiful in much of the GT back in the day. I have visited the Kiandra Field on many occasions as it is not far from me. To see the mess made of New Chum Hill by hydraulic sluicing is shocking to say the least. The hill still hasn't recovered to this very day and is an eye saw.

 

[Beer Drinker]

.

I hope you don't get too discouraged Beer Drinker thinking that too much ground might have been massively changed by man to dampen your spirits in the hunt for reef gold....Wal.

Not at all. I have been shown how the earth was changed on the old workings. I just wanted to mention how we cant always relate what we see today as being representative of how the geology would of naturally sat in the landscape back in the day.

Just sticking my noob 2c worth in. Happy to be proven wrong by people with more experience.

 

[WalnLiz]

Not at all. I have been shown how the earth was changed on the old workings. I just wanted to mention how we cant always relate what we see today as being representative of how the geology would of naturally sat in the landscape back in the day.

Just sticking my noob 2c worth in. Happy to be proven wrong by people with more experience.

Getting involved with threads is always welcome BD and a great way to get a grasp of topics that interest you.

 

[user 4386]

I for one am glad water was not that plentiful in much of the GT back in the day. I have visited the Kiandra Field on many occasions as it is not far from me. To see the mess made of New Chum Hill by hydraulic sluicing is shocking to say the least. The hill still hasn't recovered to this very day and is an eye saw.

Yes, it was an issue around Omeo-Mitta Mitta, in the rivers south from Ballarat, entire hillsides sluiced to rock at Bendigo. It diverted rivers downstream until they formed the Sludge Abatement Board. Much of the upper Bendigo Creek valley is farming arsenic-contaminated soil brought down from Bendigo.

 

[user 4386]

Not at all. I have been shown how the earth was changed on the old workings. I just wanted to mention how we cant always relate what we see today as being representative of how the geology would of naturally sat in the landscape back in the day.

Just sticking my noob 2c worth in. Happy to be proven wrong by people with more experience.

Of course your general comment about general change overall is quite accurate, particularly on the flats. Also, old records show that quartz blows at Bendigo stuck out as ribs metres high (easily mined so mostly gone now). However there is plenty of gold around reefs and downslope on the hillsides so don't despair - have a good read of WalnLiz' advice and just get out there and look,

 

[Gold Mbr2020]

The ground in "certain" areas is definitely not reflective of what it was over a150 years ago, but most surfacing was to a depth of only a few metres. It was generally chasing shallow alluvial leads where shafting was deemed too dangerous when tunnelling at such shallow depths."20 metres" would be closer to the depth of where the bedrock was for the larger "alluvial" nuggets in most of the Triangles ancient river courses, though in some areas the alluvial was substantially deeper. At this depth surfacing was rarely carried out. This is closer to the depth where shafts and tunnelling was the preferred method on most alluvial fields in the area from which many of the large nuggets were extracted.

What we are trying to determine in this thread is not "alluvial" digging but the type of geology where reefs were worked, and where the now disconnected stringers could possibly be located by mostly electrical loaming. Remember many sections of the disconnected stringers are still not exposed and some still have detectable gold within or shed from them. Stringers can have both exposed sections and sections broken away from early earth movements, especially if folding was associated at that time, giving quite a bit of horizontal separation The deep major reefs had all the gold bearing ore extracted and processed, and the lines of reefs with their many shafts generally offer only the odd bit of detectable gold thrown out with the mullock. The old timers unfortunately were very thorough.

I hope you don't get too discouraged Beer Drinker thinking that too much ground might have been massively changed by man to dampen your spirits in the hunt for reef gold....Wa

This is very interesting reading from Wal and Goldie. What I'm still confused about is what is meant by the term quartz blows and you mentioned exposed parts of stringer reefs; so what are we looking for? Quartz ironstone or mineralised quartz or both and how much of it would be exposed on average? Thanks for all this great info... Aaron