Creswick

[Oz_Gold]

Hi Folks,

A group of us are thinking about heading out Creswick way over the next week or so - just wondering if anybody has been out there of late? Any advice? Gold is where you find it of course but I'd happily accept any pointers. This is our third time out and so far we've found a lot of lead, wire and rusty cans... wouldn't mind (as I'm sure we all would) finding a little colour... one question I had - on the Geovic database when you add the layers - the red dotted alluvial areas are where you're potentially going to find gold using a detector correct? The green 'deep lead' lines are they the reefs that likely shed the alluvial gold?

Cheers

Oz_Gold

 

[BigWave]

Oz_Gold, correct: the red dotted areas are shallow diggings. The Green lines are deep leads, where they were following ancient river beds. To get reefs and faults to show, you need to get into the Geology area (Inferred)

 

[Rescue134]

Was up there a week ago. Plenty of diggings, plenty of trees down after wind storm cupple of weeks ago, stay safe with trees. River system has been cut with plenty of water going down. Good luck.

 

[Mickybees]

There's a lot of gold in creswick but it's tiny stuff you will do better there with a small coil. 8" mono works well out there.. cheers

 

[Oz_Gold]

Oz_Gold, correct: the red dotted areas are shallow diggings. The Green lines are deep leads, where they were following ancient river beds. To get reefs and faults to show, you need to get into the Geology area (Inferred)

So what layer would one select to help determine where the reefs lie? or is that a fairly specialised interpretation process?

 

[Oz_Gold]

Thanks Newbie,

We're hoping that all of the rain etc will have moved things around a little... I guess the only way to find it is to be out there

Were you detecting? did you find anything?

Was up there a week ago. Plenty of diggings, plenty of trees down after wind storm cupple of weeks ago, stay safe with trees. River system has been cut with plenty of water going down. Good luck.

 

[Tathradj]

OZ-Gold,
A lot of pointers there.
What detector are you using/hiring. ?

 

[user 4386]

"Gold is where you find it" is a pessimistic view. You can increase your chances a thousandfold by learning a little geology etc. It is where it has been deposited and that only occurs in certain limited places.

Not sure if you are highly experienced or not (so apologies if so but trying to help). Your areas should be the red dotted areas and the areas on or downslope of the reefs. I would ignore faults unless a good reason like quartz on them (most are unrelated to gold). Definitely ignore green lines, as these have gold all at greater than detector depth - except for the quartz pebble dumps from old workings - which would be a real long shot but possible for "specimen" quartz-gold pebbles or real big gold lumps that were missed on the screens. I only say this because most big pebble dumps I have bulk-sampled average up to grams per ton so have gold in them.

With the red dotted areas, look in the collar of shafts and find one you can look down (with care, even tie a rope to you if crumbly edges as they can collapse around the shaft like a cone) - if you can't see pebbles but only clay to greater depths than your detector can see, go "uphill" to shallower workings where you can see gravel. The gravel will generally be at a similar depth over an area of tens of metres or more (the streams mostly had gradients of less than 1%, the maximum being a few percent except in steep gullies where they followed the modern slope). But definitely consider the dumps around the shaft collars regardless of depth - last stuff dumped was probably from at depth on the gravel lead.

 

[user 4386]

Note that the deeper deep lead mines usually have three dumps - the quartz pebble dump, which was the coarse (and never treated) stuff they discarded off the screens (steel mesh sieve) that they passed the gravel through, the mullock dump which was the rock that they passed through getting down to the deep lead gravels and which you can tell by its lumps of basalt and sandstone, and the slums dam sands, which were the wet sands pumped out into a dam after treatment (but sometimes which now stand metres above ground if the walls have rotted or eroded away). I wouldn't waste my time on any that fit this description, not even the stuff around the shaft collar since gravel was carted far from the collar with deep shafts (eg the Madame Berry group around Creswick) although as I mentioned the pebble dump is a slight possibility. Slightly shallower leads that you can't see the gravel when looking from surface are only worth detecting the material around the collar. The best are where you can see the gravel down the shaft at realistic depths or in trenches or creek banks etc. Except in such cases, workings on completely flat ground are usually a no-no except around shaft collars.

With reefs it is simple - anywhere on top of the quartz reef and its extensions, anywhere downslope from it to the gully. For example the Welcome Stranger was at most ten to 30 m below the reef it came from, but decent small nuggets could travel many hundreds of metres downslope (but gold-bearing material will tend to be diluted by more and more barren material the further downslope you go, unless the soil cover on bedrock is very thin).

Gravity and rain are your friends.

 

[Oz_Gold]

And very helpful ones! thank you folks!

I'm hiring a GPX5000 - not sure what coil it comes with standard albeit I've asked if I could get an 8" mono

OZ-Gold,
A lot of pointers there.
What detector are you using/hiring. ?

 

[Oz_Gold]

Thanks goldierocks,

The learning part is where I'm at - I definitely wouldn't call myself experienced - I've an understanding of the basics. I've only detected three times and did a training day with Coiltek. So the red dotted areas are ultimately gravel at depth with sometimes shallow workings to access the gravel or slightly deeper to access the gravel. When they're deeper shafts go uphill with the idea that as you go uphill the gravel will gradually get closer to the surface (within detector depth).

So how can you tell the old stream paths? is it ultimately by connecting the dots from the workings? and is it generally reefs uphill that have shed the gold? Also, what is the gravel lead?

Thanks

"Gold is where you find it" is a pessimistic view. You can increase your chances a thousandfold by learning a little geology etc. It is where it has been deposited and that only occurs in certain limited places.

Not sure if you are highly experienced or not (so apologies if so but trying to help). Your areas should be the red dotted areas and the areas on or downslope of the reefs. I would ignore faults unless a good reason like quartz on them (most are unrelated to gold). Definitely ignore green lines, as these have gold all at greater than detector depth - except for the quartz pebble dumps from old workings - which would be a real long shot but possible for "specimen" quartz-gold pebbles or real big gold lumps that were missed on the screens. I only say this because most big pebble dumps I have bulk-sampled average up to grams per ton so have gold in them.

With the red dotted areas, look in the collar of shafts and find one you can look down (with care, even tie a rope to you if crumbly edges as they can collapse around the shaft like a cone) - if you can't see pebbles but only clay to greater depths than your detector can see, go "uphill" to shallower workings where you can see gravel. The gravel will generally be at a similar depth over an area of tens of metres or more (the streams mostly had gradients of less than 1%, the maximum being a few percent except in steep gullies where they followed the modern slope). But definitely consider the dumps around the shaft collars regardless of depth - last stuff dumped was probably from at depth on the gravel lead.

 

[user 4386]

Just to clarify - you will NOT get gold shed from deep leads at Creswick because they are usually at 50 to 100 m below surface on flat areas north of town. My guess is best detecting is in hills to the south (where allowed) eg along the Black Lead and tributaries and adjoining hill slopes (I live a couple of km away but have not tried Creswick - lots is restricted - but know its mining history - Black Lead was shallow in its upper reaches and produced 800,000 ounces including many, many nuggets). Happy detecting

 

[Tathradj]

Sure, Have a go with one but coming from experience,
Stick with the 11" to get the hang of the machine before going smaller.
Had the same problem with my 4500.
The 11"standard coil is a great all rounder and there is nothing wrong with them.
Above All, Have fun and be safe.

 

[Oz_Gold]

My apologies I replued to your previous comments prior to reading this - you answered some of the questions for me in this

So how can you find a reef in an area? so the gravel you refer to is that a thin layer of 'gravel' that is clearly differentiated from the soil around it? Also, if you can't see the gravel, but lots of workings, can you take the depth of the workings to assume that was the depth of the gravel and it's best to work uphill from that. Also, with the green leads is that deep alluvial

Apologies for all of the 'beginner' questions... appreciate the help.

I'm thinking of working around Slatey Creek... plenty of rain there

Note that the deeper deep lead mines usually have three dumps - the quartz pebble dump, which was the coarse (and never treated) stuff they discarded off the screens (steel mesh sieve) that they passed the gravel through, the mullock dump which was the rock that they passed through getting down to the deep lead gravels and which you can tell by its lumps of basalt and sandstone, and the slums dam sands, which were the wet sands pumped out into a dam after treatment (but sometimes which now stand metres above ground if the walls have rotted or eroded away). I wouldn't waste my time on any that fit this description, not even the stuff around the shaft collar since gravel was carted far from the collar with deep shafts (eg the Madame Berry group around Creswick) although as I mentioned the pebble dump is a slight possibility. Slightly shallower leads that you can't see the gravel when looking from surface are only worth detecting the material around the collar. The best are where you can see the gravel down the shaft at realistic depths or in trenches or creek banks etc. Except in such cases, workings on completely flat ground are usually a no-no except around shaft collars.

With reefs it is simple - anywhere on top of the quartz reef and its extensions, anywhere downslope from it to the gully. For example the Welcome Stranger was at most ten to 30 m below the reef it came from, but decent small nuggets could travel many hundreds of metres downslope (but gold-bearing material will tend to be diluted by more and more barren material the further downslope you go, unless the soil cover on bedrock is very thin).

Gravity and rain are your friends.

 

[Oz_Gold]

Can you just come and sit on my shoulder over the weekend lol - your knowledge is abundant and awesome! we're going to stick south - hoping to get a good map from Coiltek but I'd love to understand the geology of the area a little better

Just to clarify - you will NOT get gold shed from deep leads at Creswick because they are usually at 50 to 100 m below surface on flat areas north of town. My guess is best detecting is in hills to the south (where allowed) eg along the Black Lead and tributaries and adjoining hill slopes (I live a couple of km away but have not tried Creswick - lots is restricted - but know its mining history - Black Lead was shallow in its upper reaches and produced 800,000 ounces including many, many nuggets). Happy detecting

 

[Oz_Gold]

Thanks Tathradj, appreciate it!

Sure, Have a go with one but coming from experience,
Stick with the 11" to get the hang of the machine before going smaller.
Had the same problem with my 4500.
The 11"standard coil is a great all rounder and there is nothing wrong with them.
Above All, Have fun and be safe.

 

[Oz_Gold]

Is there a way of identifying on Geovic leads etc? i.e. Black lead

Just to clarify - you will NOT get gold shed from deep leads at Creswick because they are usually at 50 to 100 m below surface on flat areas north of town. My guess is best detecting is in hills to the south (where allowed) eg along the Black Lead and tributaries and adjoining hill slopes (I live a couple of km away but have not tried Creswick - lots is restricted - but know its mining history - Black Lead was shallow in its upper reaches and produced 800,000 ounces including many, many nuggets). Happy detecting

 

[user 4386]

"Thanks goldierocks,

The learning part is where I'm at - I definitely wouldn't call myself experienced - I've an understanding of the basics. I've only detected three times and did a training day with Coiltek. So the red dotted areas are ultimately gravel at depth with sometimes shallow workings to access the gravel or slightly deeper to access the gravel. When they're deeper shafts go uphill with the idea that as you go uphill the gravel will gradually get closer to the surface (within detector depth).

So how can you tell the old stream paths? is it ultimately by connecting the dots from the workings? and is it generally reefs uphill that have shed the gold? Also, what is the gravel lead?

Thanks "

You have got the basic idea I would say. Red dotted areas are basically near-surface alluvial (and eluvial) workings. Eluvial is basically soil below reefs as gold moves downhill from them. Alluvial means re-concentrated by water in a gully. stream or river. Note that with eluvial gold often is best near the source, since with coarse gold it is heavier than rock, so more rock than soil moves downhill and gold remains behind more. Alluvial (once gold has got into flowing water) can work either way, with biggest nuggets usually closest to where it first got into the strem, but fine gold can travel typically up to hundreds of metres, if very fine up to 26 km or more (eg Eldorado). I mention gravel because alluvial gold tends to concentrate in a stream in the gravel bars, it is finer and lower-grade in sand bars and usually totally uneconomic in clay. The reason is sorting by water - the mass of a large boulder, cobble or pebble of rock is similar to a small gold nugget, so they are concentrated together because of their similar mass (with rock sand only fine gold has simiolar mass, with clay the gold can be fine enough to float on the surface tension of water so often doesn't concentrate at all. This paper by a local Ballarat geo mate might help you with terminology:

https://www.prospectingaustralia.com/forum/doc/member-docs/4386/1477457534_240_giant_placers_seg_jan_2004.pdf

"Lead" is an old mining term that simply meant where the alluvial gold was concentrated (the old buried stream channel with its gravels). These were originally streams at surface, but with time they were covered with clay as the streams silted up with time as the hills were eroded away (they became slow-flowing and lower gradient, and started depositing sand and then clay rather than gravel until they became an "outwash plain" or swamp - or else volcanoes erupted like Mt Rowan near Creswick and flowed down the valley burying the streams and converting the area to a falt basalt= lava plain, as north from Crewick in the Loddon Valley). Note that clay and sand don't only accumulate more with time in a stream bed when it fiills, they also accumulate in slower-flowing areas of actively flowing streams, while gravels (and gold) tend to dump out only in faster areas of the stream (and velocity varies as streams change gradient, turn around bends, join other streams etc). So gold dumps with gravel in the fast stream channel and this is the "lead" after burial. i.e the clay and sand will keep moving even when the stream velocity is too slow to continue to carry gold and gravel, which are the only things that can dump put in the fast flowing channel.

Thus ends course on "Better than only where you find it 101"

Dead right - use Google Earth images to see the lines of shaft dumps and areas of turned-over ground (although they can be overgrown and difficult to see), otherwise walk up hill from dump to dump.

 

[Mickybees]

Sure, Have a go with one but coming from experience,
Stick with the 11" to get the hang of the machine before going smaller.
Had the same problem with my 4500.
The 11"standard coil is a great all rounder and there is nothing wrong with them.
Above All, Have fun and be safe.

Hi I'm sorry but I disagree. For a beginner the 8" is easier to use and to locate your target very easy to pin point with the 8"
The 11" is also a great coil but for creswick I wouldn't recommend it ..it's small gold and even my 11" elite struggles to find the gold there but with the 8" mono you can pick up 0.01g nuggets all day long ...

 

[Oz_Gold]

So are there any places where there are still nice size nuggets?

Sure, Have a go with one but coming from experience,
Stick with the 11" to get the hang of the machine before going smaller.
Had the same problem with my 4500.
The 11"standard coil is a great all rounder and there is nothing wrong with them.
Above All, Have fun and be safe.

Hi I'm sorry but I disagree. For a beginner the 8" is easier to use and to locate your target very easy to pin point with the 8"
The 11" is also a great coil but for creswick I wouldn't recommend it ..it's small gold and even my 11" elite struggles to find the gold there but with the 8" mono you can pick up 0.01g nuggets all day long ...