The Stamping Ground Gold Mine

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michael
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Postby michael » Fri Jul 27, 2007 4:26 pm

Hi Glen the stamp mill is looking great, so tell me so that I dont have to go and do research what is a stamp mill exactly? I have seen some elaborate models of stamp mills and have often wondered what they do.

I know they stamp... but what? and how does the process fit into the chain of events in the mine?
Regards Michael
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Postby andrew milner » Fri Jul 27, 2007 4:34 pm

Glad you asked that Michael :D I know there are no 'stupid questions' but I thought that was close so didn't ask :lol:
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Glen A
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Postby Glen A » Fri Jul 27, 2007 9:47 pm

michael wrote:Hi Glen the stamp mill is looking great, so tell me so that I dont have to go and do research what is a stamp mill exactly? I have seen some elaborate models of stamp mills and have often wondered what they do.

I know they stamp... but what? and how does the process fit into the chain of events in the mine?


As I understand it, the process is something like this:

Gold is very, very fine. You can't just go underground and pick up pieces of gold, because 'nuggets' the size you see in picture books are very rare. Most of it is as small as a pin head and is often embedded in rock (quatz).
So they bring the rock out and smash it up into little pieces (the stamp mill), so the gold gets seperated from the rock. I guess it is like a powder after it comes out. It then gets washed out (by water) and over those tables in the front. The tables have a copper top and some chemical (which I can't think of right now) is rubbed over the copper, so the gold 'sticks' to the table while the rest of the rock gets washed over the end and off into a big pile.

So after they stop the mill they can collect up all the gold off the table, and melt it into a blob.

Even then some gold will have escaped out in to the waste pile, so somtimes that gets put through another acid chemical process to try and extract more gold out of it.

I'll post the proper names of the chemicals latter, after I have looked them up (unless someone else beats me to it).

Thats is one thing I like about model trains; You often learn about other things in life as part of your research to get your model right. In order to build your model right you have to have a basic understanding of what it does. I didn't know anything about stamp mills either before I started.

It is the same with scenery. To get a good looking hill you need to have a basic understanding of geology. And to build a building you need to understand basic architecture and building proccess.
Most modellershave studied these things without even realising it.

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Postby SOUTHPASS » Fri Jul 27, 2007 11:33 pm

G,day....Don't quote me on this, but I think one of the chemicals used on the tables was mercury.....
.....WARNING....
Contains images that anoraks may find disturbing.
1:24 scale 16.5mm gauge.
Yes I know it's all old and rusty, but I just model things as I see them......
Have a good one....John B.

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Postby Steve Bennett » Sat Jul 28, 2007 10:06 pm

SOUTHPASS wrote:G,day....Don't quote me on this, but I think one of the chemicals used on the tables was mercury.....


Quite right John, Mercury is used to pick up the particles of gold, both have similar weight and suspension properties. Later in the process, the mercury is burnt off, leaving the gold behind, though I'm not exactly certain how that works.

I suppose the easiest way to understand how the stamps work is to think of it as a mortar and pestle. The stamps crush the mineral bearing rock down into very fine particles by being dropped down on the rock continuously. The cams seen on Glen's model, lift the stamp rods, then allow them to drop under gravity, pounding the rock down. Water is fed into the base of the stamps which washes the finer particles out though a small slit onto the table in front. The larger particles wont go through and stay in the base of the stamps until crushed fine enough to escape. I hope that makes some kinda sense :) it is fairly easy to understand how they work once you have seen one in action.
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Postby DCRfan » Sun Jul 29, 2007 1:07 am

That is looking really good. I certainly can't see anything technically wrong with it.

With all the stamps a stamping you will need a strong baseboard :twisted:
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Postby Dave O. » Sun Jul 29, 2007 2:50 am

Glen,

You've built a very nice model -- I would not have believed the scale if it weren't for the newspaper shown in the photo -- or is that an enlarged newspaper? :P

If someone was able to provide you with a page long list of technical errors in the model, then I'd submit that their knowlege on stamp mills may be 'unhealthy' (as I'd have probably rolled the paper up and poked them in the eye with it!). :lol:

Excellent work, well done. Dave O.
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Glen A
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Postby Glen A » Mon Jul 30, 2007 1:01 am

Steve Bennett wrote:Quite right John, Mercury is used to pick up the particles of gold, both have similar weight and suspension properties. Later in the process, the mercury is burnt off, leaving the gold behind, though I'm not exactly certain how that works.


Cyanide was the other chemical I was thinking of. But that process involved a big tank and I think it took a couple of days for the cyanide to turn the gold to liquid. Somehow it got skimmed off and another chemical process turned it back to solid. The book did explain it, but it all went over my head. Chemistry was never one of my strong subjects at school. :(

Anyway now for the recent news:
In a moment of bravery (or absolute stupidity :twisted: ) I offered the organiser of the local model train show, a Gn15 layout for the this years October show.
The trouble is that I don't have a Gn15 layout, or any completed rolling stock yet, just a 80% complete stamping battery.
So now it's time to pull finger and get some work done! (deadlines are always good for that).

At the weekend I went out to the hardware shop and got some wood, glued and screwed it together, and now I have two modules. (The track plan in my head actually has 3 modules in it, but I think I only going to have time for two by October).

So I better go and get on with it!
Photos will come later when there is more to show.

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Stamp Mills.....

Postby Joe Raymaker » Mon Jul 30, 2007 3:49 am

Roger Lescohier's book: "The Stamp Mill for Recovery of Gold from Hard
Rock", describes amalgamation with mercury. Copper plates surfaced with mercury were placed in front of the flow of the slurry, and by a rolling sort of wash in which the same slurry came in contact with the plate over and over, the gold was amalgamated. The slurry was no more than gold and sand and water. The reason for this process was that there were only a couple of ounces of gold in a ton of slurry; there had to be an efficient way to collect it. How the amalgam was removed from the plates I didn't study.

He wrote about the process of cyanidation in a separate pamphlet :(
except to say that cyanidation was a process for recovery of the REST of the gold remaining after amalgamization.

Cornish miners joined the gold rush only after placer mining("panning" or other means) for surface gold had been exhausted, and hard rock mining became the method. Thing is, the men did the mining and the stamping, but the women were the ones who broke the large rocks with a sledge, to get them small enough to go into the stamp mill. Bal maidens, they were called.

Dan, you got enough rolling stock to get you through this reckless promise you made? :) I suppose some of us might mail you a car a piece?

JR 8)

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Postby michael » Tue Jul 31, 2007 3:00 am

Thanks everyone for the explanation of the process. :)
Regards Michael

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Postby Glen A » Tue Jul 31, 2007 8:25 pm

The first of the wagon fleet (not finished yet):
Image

There are another 3 similar ones still in the production line.

Tonight, all going well, I will be in the garage starting on the tippler for it.

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Glen's Wagon

Postby Joe Raymaker » Tue Jul 31, 2007 10:00 pm

Nice looking work, Glen; thanks for showing it :!:

Gives me an :idea: about how to finish some of my stuff.

JR 8)

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Postby Korschtal » Wed Aug 01, 2007 5:05 am

Really nice modelling Glen. I do hope you will make a video of this when its all running so we can appreciate the stamping in action... I like the wagons as well...

Copper, mercury and Cyanide... Lovely. I can just imagine what the "Environmental Spokesman" for the company would have said:

"Because our presses are far more modern than those of other companies, we dump 30% less heavy metals into the local rivers, causing far less damage and mutation to the local fish..."
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Postby Glen A » Tue Aug 07, 2007 8:18 pm

Here is the tippler so far. I'm running a bit behind schedule (only 8 weeks untill this non-existant layout goes on show).

As you can probably see, it is an end-over-end tippler. I understand the side rotating ones were much more common.
But I think this one looks much more dramatic, and more likely to be noticed as it is towards the back of the module.

I sill need to add some guides at the top to hold the wagon in when it turns upside down. I also need to add pulley for motorisation, but I think that will be the easy bit at the end.

Image

Image

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Postby Steve Bennett » Tue Aug 07, 2007 9:41 pm

Glen A wrote:As you can probably see, it is an end-over-end tippler. I understand the side rotating ones were much more common.
But I think this one looks much more dramatic, and more likely to be noticed as it is towards the back of the module.


Quite the opposite Glen, simple tipping devices like this were much more common than rotary ones, which were more expensive, difficult to install and took up much more space. It just appears that way, as it is the larger operations and those with high volumes of material that used the rotary type, just so happens they were also more likely to be photographed and recorded. You have chosen wisely for a smaller mine and a very nice job you have made of it.
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Postby Rockley Bottom » Wed Aug 08, 2007 2:26 am

Glen

Great design. It could solve a problem I have could use a modified design

Ralph

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Postby Rockley Bottom » Wed Aug 08, 2007 2:29 am

Glen

Great idea could use the same pattern on my dockside

Ralph

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Postby Rockley Bottom » Wed Aug 08, 2007 2:30 am

Glen

Great idea could use the same pattern on my dockside

Ralph

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Postby andrew milner » Wed Aug 08, 2007 6:01 pm

Ralph, hope you're not on a pay per post site!

Nice modelling Glen :D
Andrew Milner, still trying to figure it out....

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Postby Rockley Bottom » Wed Aug 08, 2007 9:39 pm

I think the little green men are after me :twisted: :twisted: Photo bucket went of line, Then I was told it would not axcept my maillings to the site :!:

I think I will have to send contributions by post card :wink:

Ralph
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Postby Rockley Bottom » Wed Aug 08, 2007 9:42 pm

Is any body else being driven mad with de-bug notices :?: :?:

Ralph

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Postby Steve Bennett » Wed Aug 08, 2007 9:44 pm

Rockley Bottom wrote:Is any body else being driven mad with de-bug notices :?: :?:


Yes, i think we are all getting them, just ignore them. You will find that even when you get the message, your post will have been accepted and posted.
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Postby Glen A » Mon Aug 13, 2007 8:19 pm

Well next item is now almost ready; the loading 'bins' which will feed the stamp battery. I forgot to include a ruler or person in the photo so you get an idea of scale. It is 15cm tall, so not really huge in the scheme of Gn15. The wooden slats are made from iceblock sticks.

There is no chain to lift the doors. That is because I may put an axle shaft across the front with gears etc which will turn when the rest of the drive belts are running. They won’t actually move the feed doors (they are glued in place) but it will be something else moving which will catch the eye and distract from deficiencies in my modelling. This will be located behind the stamp battery, and will have a feed table out the front, so there is detail missing at the bottom because you will never see it. I am slack like that - don't built what the public can't see :wink:

Image

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Postby Gerry Bullock » Wed Aug 15, 2007 5:47 am

Glen A wrote: This will be located behind the stamp battery, and will have a feed table out the front, so there is detail missing at the bottom because you will never see it. I am slack like that - don't built what the public can't see :wink:



Seems to me a good KISS principle Glen. I Like the way it's developing, look forward to seeing the whole assembly. 8)
So little time, so many ideas!!!!! GerryB.
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Postby Glen A » Wed Aug 15, 2007 8:38 pm

Gerry Bullock wrote: I Like the way it's developing, look forward to seeing the whole assembly. 8)


Thanks Gerry. I was going to start laying it all out last night, but it was cold out in the garage and I was tried, so I stayed inside and started on the incline trolley (based on Dinorwig Welsh slate mine). It is half built now so maybe photos soon.
Hopefully the general layout might start this weekend, although SWMBO did mention about me getting some compost and digging the garden this weekend :(


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