Old river

[bbayjohn]

Hi folks, I thought I would give a bit of an update. We still haven't found the gold yet but we are having fun trying. On a recent trip to a local mine up in the hills we came across some river rocks. The odd thing is, we are on top of a mountain miles from any river.

Any ideas what I should lookout for?

 

[Rockhunter62]

Yeh, the local council truck driver who delivered them there.

Cheers

Doug

 

[bbayjohn]

lol, Hi Doug, I'm not totally sure that these rocks were delivered here. In the below photo is of the cut out of the road in the side of the mountain.

 

[Moneybox]

That sure looks like alluvial gravel in the bank but is there gold in the area? There's not much of this country that missed the scrutiny of the oldtimers. If there are no workings nearby and no glass fragments or rusty remains perhaps there's no gold there however it doesn't hurt to try. I see that you were headed to an old mine. Was it a gold mine?

 

[Occasional_panner]

Look closer to the bottom where bigger rocks are, that's where they fell from suspension and possibly the (heavy) gold with it.
Don't know about other states but vic has a site called geovic which shows mineral area around the state.
That's certainly river rock, look further away from the road though as graders often move material to the sides, unlikely they used river rocks for road base.
Certainly worth a look, there is a quartz vein going through one of those rocks, no guarantee, but a good sign.

 

[bbayjohn]

Hi Moneybox, we were indeed headed to an old gold mine. the gravel is 241m elevation. Very interesting area.

 

[bbayjohn]

Hi Occasional_panner, We would love to find the larger rocks. We are trying to ascertain just were this possible ancient river bed actually ran. It should be no older than 150 million years, however that leaves a lot of time to research. I am not a historian or a geologist unfortunately. Woah to my lost youth.

 

[Guessologist]

Without knowing the spot, there's a couple of options:

- old river channel - possible, hard to get a feel from the picture. I'd look for any sign of imbrication of the pebbles (leaning up against each other in one direction like shingles), or even vague layering, that would be more convincing of water action. The round pebbles indicate that they have travelled a decent distance, so if it's an old channel, it probably dates back to a time when the whole area was a plain before geological uplift resulted in the 'dissection' of it into mountains.

- pebbles eroded from an underlying bed of conglomerate , I see this a lot between Heathcote and Nagambie and looks very much like old river cobbles, although the origin is actually more like near-shore ocean sediments.

- road metal

I've found individual water-worn pebbles far from watercourses in Broken Hill before, that I can only assume were either dropped by people or even emu gizzard stones.

 

[AussieChris]

Certainly, no harm in running a few test samples, a couple of 20l buckets panned should tell you if there is any colour there.

I have run eroded dirt from road cuttings that are clearly through water-worn gravel (don't worry I don't dig into the cutting, merely scraped up a few buckets of gravel/soil that have washed off them) It's surprising where you find good colour.

My latest spot I have been working the last few months was always a place I never even bothered with in the past, I finally gave in and decided to run a few pans.....suffice to say the spot has kept me going back. The trade up being the gold is very fine compared to the Turon but there seems to be enough of it, and at the end of the day I'm happy to have it in the vial.

The old-timers were certainly thorough, but there are odd spots they looked past, mostly I'm guessing because it was not worth their effort, but a few hours on the shovel for a couple of grams reward is satisfying to most of us these days.

I envy all of you who are still out at it, certainly cooled off here.....I might have to brave the cold and go run a few buckets in the morning.

 

[bbayjohn]

Wow, thanks Guessologist. I have been leaning toward your first option, with the little research I have done, eg maps, aboriginal stories ect. I remember as a child seeing a map showing the ancient rivers, however I have been unable to locate one recently. We have been exploring the area and taking elevation readings at numerous sites attempting to gain a perspective of what it may have looked like. There are definitely too many river stones at the altitude for it to be dropped by people or animals. The terrain is very rugged and the only reason this is visible is due to the constant grading of the road. In parts this would have been more than a metre below ground level. A 'river' (not much left) does still run some distance from this site. Any suggestions on finding information that may help? If I can figure it out, I'll let you know. Cheers

 

[Goldfreak]

lol, Hi Doug, I'm not totally sure that these rocks were delivered here. In the below photo is of the cut out of the road in the side of the mountain. https://www.prospectingaustralia.co...1528026862_screenshot_2018-06-03_21.45.06.jpg

Good sport :Y:

 

[Guessologist]

Any suggestions on finding information that may help?

I can only really talk for Victoria, and I'll go ahead and do so for the benefit of anyone else even if you're somewhere else, but my first stop would be the state government's Energy and Earth Resources online store: http://earthresources.efirst.com.au/categories.asp?cID=4 I'm sure it's a popular referral on this board!

All of the state geological maps, past and present, are on there as free downloads, and it's worth grabbing the corresponding geological report to go with it to help you make sense of it. They usually have a fairly in-depth review of the mining history of the map sheet which is worth reading as well. Of course the government geologists always miss stuff, so it might not have what you're looking for in the right spot. The hand-drawn historical maps are often more informative than the modern digital versions of course!

You can also try the GeoVic app to create your own maps if you feel like it: http://er-info.dpi.vic.gov.au/sd_weave/anonymous.html

 

[bbayjohn]

Any suggestions on finding information that may help?

I can only really talk for Victoria, and I'll go ahead and do so for the benefit of anyone else even if you're somewhere else, but my first stop would be the state government's Energy and Earth Resources online store: http://earthresources.efirst.com.au/categories.asp?cID=4 I'm sure it's a popular referral on this board!

All of the state geological maps, past and present, are on there as free downloads, and it's worth grabbing the corresponding geological report to go with it to help you make sense of it. They usually have a fairly in-depth review of the mining history of the map sheet which is worth reading as well. Of course the government geologists always miss stuff, so it might not have what you're looking for in the right spot. The hand-drawn historical maps are often more informative than the modern digital versions of course!

You can also try the GeoVic app to create your own maps if you feel like it: http://er-info.dpi.vic.gov.au/sd_weave/anonymous.html

Thanks again Guessologist. I should have stated that we are in NSW. I will check it out. there is sooo much information to sort through and a lot of terminology to learn. Hopefully we will find a sweet spot. If not knowledge is gold.

 

[OzzieAu]

I find this geological overlay on Google Earth is a good resource.
https://macrostrat.org/map/#5/-24.707/135.176

 

[Occasional_panner]

Shovel,bucket and pan will tell you all you need to know, research is good too though.

 

[Wally69]

You will find deep leads up high in the Mogo State Forest that the old timers worked. The colour of the stone reminds me of some of the workings I have seen there.

 

[user 4386]

These old river systems were on a fairly low topographic relief plain that was subsequently uplifted and eroded, so that remnants remain high on hills. Some worked for gold.