Originally Posted by El Siglo
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?)