Boards.ie uses cookies. By continuing to browse this site you are agreeing to our use of cookies. Click here to find out more x
Post Reply  
 
 
Thread Tools Search this Thread
12-06-2012, 18:55   #16
slowburner
Moderator
 
slowburner's Avatar
 
Join Date: May 2009
Posts: 4,472
Quote:
Originally Posted by El Siglo View Post
Anywhere there's a sulfide deposit you should have a look into. Keep an eye on plants and how healthy they look (i.e. certain metals will affect plant metabolism through discolouration of leaves). So when you're looking for gold, the pathfinder element you want to bear in mind is arsenic. So, if you see plants check out their roots they'll have stunted growth and appear in a sort of brownish colour. Overall the growth of the plants will be reduced with arsenic concentrations in the soil of >2 ppm.
The Avoca mines in Wicklow (sorry), still have colossal spoil heaps full of sulphides and arsenic too.
The mines ceased commercial operation in 1982, but still precious little grows on the most exposed heaps, and those few that manage to eke out an existence, are more like bonsai than mature trees.
A walk around the mines (which you're not supposed to do ) fills the nostrils with sulphur especially on a warm day.
There was an outbreak of cholera in the surrounding area towards the end of the C.19th - Avoca was largely unscathed, and this has been attributed to the quantity of sulphur in the air and water.

I heard fairly recently, that a joint Irish/Canadian venture has found gold nearby in commercially viable quantities.
slowburner is offline  
Advertisement
12-06-2012, 20:29   #17
El Siglo
Registered User
 
El Siglo's Avatar
 
Join Date: Sep 2007
Posts: 3,670
Send a message via Skype™ to El Siglo
Quote:
Originally Posted by slowburner View Post
The Avoca mines in Wicklow (sorry), still have colossal spoil heaps full of sulphides and arsenic too.
The mines ceased commercial operation in 1982, but still precious little grows on the most exposed heaps, and those few that manage to eke out an existence, are more like bonsai than mature trees.
A walk around the mines (which you're not supposed to do ) fills the nostrils with sulphur especially on a warm day.
There was an outbreak of cholera in the surrounding area towards the end of the C.19th - Avoca was largely unscathed, and this has been attributed to the quantity of sulphur in the air and water.

I heard fairly recently, that a joint Irish/Canadian venture has found gold nearby in commercially viable quantities.
The use of plants in geobotanical surveys for mineral resource evaluation was done in the time before atomic absorption and ICP-OES equipment was invented (a long time ago) and since most sulphide ores are usually associated with sulphur, copper, zinc, silver, gold, lead and uranium it paid to notice these things about plants in the area especially if it was sulphide deposit like the massive granite pluton down in Wicklow.

Nowadays I don't think anyone does geobotanical surveys as you can buy a handheld XRF for about £50,000 and do the job in a matter of seconds, what used to take days.

Acid mine drainage (AMD) is caused by the oxidation and hydrolysis of metal sulphides (mainly pyrite) in water permeable strata, or in mined spoil dumped on the surface. This results in the formation of several soluble hydrous iron sulphates, the production of acidity and the subsequent leaching of metals. It's a slightly different to prospecting using geobotanical surveys as it's an impacted site and is attributed to mining activity as the two main mining adits in the case of the Avoca represent about 70% of the AMD discharge from the mines with the remainder coming from the other sources including minor contaminated streams, bank infiltration, and as groundwater discharge.

I spent a lot of time down there doing work on it for my masters and I'm just reading over an article an old lecturer of mine wrote a few years back on one of the geochemical methods he used. So, it's slightly fresh in my head!
El Siglo is offline  
(2) thanks from:
12-06-2012, 21:01   #18
slowburner
Moderator
 
slowburner's Avatar
 
Join Date: May 2009
Posts: 4,472
Ha - now I have an expert to quiz.

Seriously though, it must be one of the most studied sites in Ireland from many points of view.
Geologists, ecologists, historians (too few), hydrologists, biologists (and more 'ists than I can think of), have all studied the place.

I've been very fortunate to know two mining experts who brought me on a tour of the 850 level. It turned out to be a five hour journey up ladders, through C18th levels, C19th levels and all around the raises and stopes of latter years.
It was one hell of an experience, but tinged with sadness, knowing those levels will probably collapse long before the loss of heritage is recognised, or the public ever gets to see a truly remarkable and extensive feat of engineering.
slowburner is offline  
12-06-2012, 21:41   #19
El Siglo
Registered User
 
El Siglo's Avatar
 
Join Date: Sep 2007
Posts: 3,670
Send a message via Skype™ to El Siglo
Quote:
Originally Posted by slowburner View Post
Ha - now I have an expert to quiz.

Seriously though, it must be one of the most studied sites in Ireland from many points of view.
Geologists, ecologists, historians (too few), hydrologists, biologists (and more 'ists than I can think of), have all studied the place.

I've been very fortunate to know two mining experts who brought me on a tour of the 850 level. It turned out to be a five hour journey up ladders, through C18th levels, C19th levels and all around the raises and stopes of latter years.
It was one hell of an experience, but tinged with sadness, knowing those levels will probably collapse long before the loss of heritage is recognised, or the public ever gets to see a truly remarkable and extensive feat of engineering.
It's an interesting site to have alright, great history to it as well. From the Roman traders to the Associated Irish Mine Company and the Cronebane halfpenny and the use of it as a rubbish dump by Wicklow County Council! A lot of work has been done out of TCD on it, but that's the stuff I'm more familiar with.

The problem with Avoca is that when it shut down it wasn't economic (i.e. for it to be economic you'd want to be getting a 5% copper yield out of the rock extracted and they were down to about 2%). However, with better technology and copper prices rising (along with gold and all the other sulphate minerals), Avoca will be economically viable in a short space of time (at least that's what a few people in the GSI hope anyway, they have the property rights to the site as far as I can recall). So the will to clean up the site isn't there as the site may be used again shortly, hence why the place is such a mess. Not great form since some of the vertical adits were 'sealed' by dumping a few Ford cortinas and datsuns with some gravel and soil on top, the cars have corroded (AMD groundwater) and the shafts are unstable at the top entrance. This is a great article to read on some of the monitoring work carried out on the site: http://dx.doi.org/10.1016/S0043-1354(97)00449-1
El Siglo is offline  
Thanks from:
13-06-2012, 07:16   #20
slowburner
Moderator
 
slowburner's Avatar
 
Join Date: May 2009
Posts: 4,472
Quote:
Originally Posted by El Siglo View Post
It's an interesting site to have alright, great history to it as well. From the Roman traders to the Associated Irish Mine Company and the Cronebane halfpenny and the use of it as a rubbish dump by Wicklow County Council! A lot of work has been done out of TCD on it, but that's the stuff I'm more familiar with.

The problem with Avoca is that when it shut down it wasn't economic (i.e. for it to be economic you'd want to be getting a 5% copper yield out of the rock extracted and they were down to about 2%). However, with better technology and copper prices rising (along with gold and all the other sulphate minerals), Avoca will be economically viable in a short space of time (at least that's what a few people in the GSI hope anyway, they have the property rights to the site as far as I can recall). So the will to clean up the site isn't there as the site may be used again shortly, hence why the place is such a mess. Not great form since some of the vertical adits were 'sealed' by dumping a few Ford cortinas and datsuns with some gravel and soil on top, the cars have corroded (AMD groundwater) and the shafts are unstable at the top entrance. This is a great article to read on some of the monitoring work carried out on the site: http://dx.doi.org/10.1016/S0043-1354(97)00449-1
Apologies to Bogwalrus.

The EPA has a more recent report (2007) available to download here
There have been some significant changes since Gray's 1998 report: most notably, he observed a river devoid of fish life down to the estuary, and a predominance of diptera, which are a biotic index of pollution.
Migratory fish have returned to the river - indeed, the record sea trout for Ireland was caught below Woodenbridge last year.
The intensively polluted stretch is now much shorter. I'm not aware of any biotic indexing work carried out lately, but I'll bet the diptera are less predominant.
I think the pace at which the river is recovering has surprised many observers.
Undoubtedly, the deep adits continue to discharge heavy mineral deposits directly into the river. I saw amazing 'copper flowers' which had precipitated onto ferrous fragments when I was in the deep adit.
However, I don't think anyone predicted the phenomenon of concretion.
My knowledge of this is just from bits and pieces I've heard locally - one man told me about trying to move what looked like loose spoil - he said it nearly broke his JCB!
If this concretion thing is true, it could reduce runoff from the spoil heaps.

There was also a joint Welsh/Irish project to test the viability of treating the discharge from Ballymurtagh using crushed limestone (I think) - after treatment the water was potable, and the plant was not expensive in terms of how it could contribute to the economy. Nothing ever came of it unfortunately.

I'd better drag myself away from the screen or I'll never shut up.


(One more thing - where did you see or hear the reference to Roman traders?)
slowburner is offline  
Advertisement
19-06-2012, 18:33   #21
bogwalrus
Registered User
 
bogwalrus's Avatar
 
Join Date: Nov 2005
Posts: 1,401
Baldric says there is gold in Ireland. I believe him


bogwalrus is offline  
Thanks from:
19-06-2012, 19:52   #22
slowburner
Moderator
 
slowburner's Avatar
 
Join Date: May 2009
Posts: 4,472
Interesting vid.

Here's a view inside a Wicklow adit. It was driven in to 700 fathoms just before the famine.
Every inch of it was cut by hand, just using a pick.
The adit was driven in search of gold but not a single particle was found.






I can't find any evidence for the existence of this trial adit, but I'm nearly sure it's later. Note the pyrites or Fool's gold above, and to the right of the bore mark at the top of the portal.

Attached Images
File Type: jpg Late C.19th Wicklow adit.jpg (209.7 KB, 788 views)
File Type: jpg Weaver's adit.jpg (101.1 KB, 795 views)
slowburner is offline  
(2) thanks from:
26-06-2012, 18:43   #23
bogwalrus
Registered User
 
bogwalrus's Avatar
 
Join Date: Nov 2005
Posts: 1,401
Just a question on gold Mineralisation.

What chemicals/tools could i use to extract gold in lets say a load of copper/iron rich soils?
bogwalrus is offline  
26-06-2012, 19:35   #24
Step23
Registered User
 
Step23's Avatar
 
Join Date: Jun 2010
Posts: 127
Well you would probably need a couple of tonnes of ore to start with then you would need an ore processing plant, to process the ore to make concentrate. You'd then send off the concentrate to a smelter and then you would have your gold! So unless you are a mining company you probably won't get any gold from ore as the gold is so highly disseminated that you need tonnes of ore just to get a few onces.

However, if you are looking at ore that has produced gold in the past, look for gossan, this is altered parts of the ore and is basically rust, because gold is so stable and doesnt tarnish it may be possible to spot some in the gossan. And remember to look at any quartz veins you find, you can always collect a few lumps, crush it to powder and pan it to see if it contains any gold.

Good luck!

Last edited by Step23; 26-06-2012 at 19:37.
Step23 is offline  
Thanks from:
Advertisement
26-06-2012, 21:47   #25
slowburner
Moderator
 
slowburner's Avatar
 
Join Date: May 2009
Posts: 4,472
...or you could try the technique of the Golden Fleece.
I think it was used in China, but I could be wrong.
It involved setting up the fleece (shag pile carpet might be just as good) in a fast flowing part of the gold bearing stream.
The likely soil was shoveled into the water, just above the fleece.
The principle is that the heavier gold particles sink to the bottom of the fibres, and get trapped.
The old timers would then burn the fleece - the idea being that the gold would melt, and be easily sorted from the spoil.

Edit: modern day gold miners use miners' moss


Last edited by slowburner; 27-06-2012 at 10:40.
slowburner is offline  
Thanks from:
27-06-2012, 10:20   #26
bogwalrus
Registered User
 
bogwalrus's Avatar
 
Join Date: Nov 2005
Posts: 1,401
Quote:
Originally Posted by Step23 View Post
Well you would probably need a couple of tonnes of ore to start with then you would need an ore processing plant, to process the ore to make concentrate. You'd then send off the concentrate to a smelter and then you would have your gold! So unless you are a mining company you probably won't get any gold from ore as the gold is so highly disseminated that you need tonnes of ore just to get a few onces.

However, if you are looking at ore that has produced gold in the past, look for gossan, this is altered parts of the ore and is basically rust, because gold is so stable and doesnt tarnish it may be possible to spot some in the gossan. And remember to look at any quartz veins you find, you can always collect a few lumps, crush it to powder and pan it to see if it contains any gold.

Good luck!
Very true,

The idea was that maybe if i fill a couple of buckets of finer sand i could test to see if there are any traces of gold, even very minute diluted traces. If so then technically i have found gold and that area might be worth further investigation.


Devonian areas like here in the south of Ireland should contain Gold mineralisation. Some soil per tonne could yield 2 ounces. Others 10 grammes.

Basically what i am looking for is a chemical of sorts that can colour or do something to show diluted gold etc.
bogwalrus is offline  
27-06-2012, 22:04   #27
Step23
Registered User
 
Step23's Avatar
 
Join Date: Jun 2010
Posts: 127
If you do find yourself with gold containing soil, use sieves to get the grain size as fine as possible, then pan it, you could have some gold. I'm not sure what chemicals you could use to test for gold. I know aqua regia will dissolve gold, but that is horrible stuff, exteremly corrosive!

I'd suggest a quick google for panning forums etc they could be of some help to you too.

Hope this helps!
Step23 is offline  
28-06-2012, 10:19   #28
El Siglo
Registered User
 
El Siglo's Avatar
 
Join Date: Sep 2007
Posts: 3,670
Send a message via Skype™ to El Siglo
Quote:
Originally Posted by slowburner View Post
Apologies to Bogwalrus.

The EPA has a more recent report (2007) available to download here
There have been some significant changes since Gray's 1998 report: most notably, he observed a river devoid of fish life down to the estuary, and a predominance of diptera, which are a biotic index of pollution.
Migratory fish have returned to the river - indeed, the record sea trout for Ireland was caught below Woodenbridge last year.
The intensively polluted stretch is now much shorter. I'm not aware of any biotic indexing work carried out lately, but I'll bet the diptera are less predominant.
I think the pace at which the river is recovering has surprised many observers.
Undoubtedly, the deep adits continue to discharge heavy mineral deposits directly into the river. I saw amazing 'copper flowers' which had precipitated onto ferrous fragments when I was in the deep adit.
However, I don't think anyone predicted the phenomenon of concretion.
My knowledge of this is just from bits and pieces I've heard locally - one man told me about trying to move what looked like loose spoil - he said it nearly broke his JCB!
If this concretion thing is true, it could reduce runoff from the spoil heaps.

There was also a joint Welsh/Irish project to test the viability of treating the discharge from Ballymurtagh using crushed limestone (I think) - after treatment the water was potable, and the plant was not expensive in terms of how it could contribute to the economy. Nothing ever came of it unfortunately.

I'd better drag myself away from the screen or I'll never shut up.


(One more thing - where did you see or hear the reference to Roman traders?)
Nick Gray told me about the Roman traders.

Recovery of these kinds of environments is not uncommon, I mean even in the exclusion zone of Chernobyl there's a fair abundance of wildlife which has totally surprised people. What you see in the Avonmore and Avoca is that most of the metals undergo numerous changes in their speciation due to dissolution, precipitation, sorption and complexation phenomena when discharged into a water body. Upon entering the river etc... the metals will distribute between the aqueous phase and the suspended sediments during transport. So the metals tend to be assimilated in sediment with organic matter, Fe/Mn oxides, sulphides, and clay forming several reactive components. So really sediment is always regarded as the potential reservoir for metals and plays an important role in adsorption of dissolved heavy metals. So you won't find as much heavy metals in the actual water column but you will find them in the sediment and having done this before this is usually the case, the dissolved metal concentrations are fairly low in comparison to the bulk sediment and we were using an ICP-OES for metals and cations.
El Siglo is offline  
Thanks from:
28-06-2012, 10:32   #29
slowburner
Moderator
 
slowburner's Avatar
 
Join Date: May 2009
Posts: 4,472
There are colloquial references to the Romans alright, but nothing more solid than that.
Did Nick Gray say anything specific about them?
slowburner is offline  
28-06-2012, 11:42   #30
El Siglo
Registered User
 
El Siglo's Avatar
 
Join Date: Sep 2007
Posts: 3,670
Send a message via Skype™ to El Siglo
Quote:
Originally Posted by slowburner View Post
There are colloquial references to the Romans alright, but nothing more solid than that.
Did Nick Gray say anything specific about them?
Not to best of my recollection, it wasn't really the focus of our work just something cursory to give the place context and really his inimitable way of getting us to think outside of the box. When we were brought out on site (over the course of 2 days) we did a walk around, he started off on the very beginning of operations and right up to the present day state of the place. Has there every been any proper archaeological surveys done? Sure there's stuff preserved in the surrounding peat bogs etc...
El Siglo is offline  
Post Reply

Quick Reply
Message:
Remove Text Formatting
Bold
Italic
Underline

Insert Image
Wrap [QUOTE] tags around selected text
 
Decrease Size
Increase Size
Please sign up or log in to join the discussion

Thread Tools Search this Thread
Search this Thread:

Advanced Search



Share Tweet