That's a fair old loading. I wonder how much is actually a suspension of solids, rather than being truly dissolved.
Since the acidity will largely be caused by H2SO4 from sulphides, it follows that the acid will react with metals to form soluble sulphates.
You could ditch them all out by chucking in something more reactive like finely divided aluminium, snag is the price of aluminium and the you would be left with a mixed metal sludge. You would then have to dream up a way of separating them, which there are a lot of ways, often wasteful and usually very expensive.
What I would propose is something along the lines of that done at Bissoe. If you are going to use Iron to precipitate copper by Fe+CuSO4==>FeSO4+Cu you need to get the acidity to such a level that the iron doesn't get changed into Iron Sulphate.
Chucking a load of steel wool/swarf into the county adit runoff is a good idea if you ask me. I reckon it would be possible to install the whole thing in big plastic barrels. It would also be good for the environment... maaaaaaan.
I've often thought about potential uses for ochre whilst wading through it.
I think that if you have a saturated solution of "stuff", your only hopes are electrolysis or precipitation, both of which are tricky to do on a profitable scale, without some big equipment. Also, in order to precipitate a Kg of copper, you will need a fair amount of electricity, time and solution!!!! Good luck humping it around in barrels, or do you plan to use a hose?
I reckon the steel wool idea is the best.
Since I have a day off today, I can spare enouigh time to have a moan about ochre release and awful pollution.
I have had it outlined to me that certain adits are off limits due to ochre release and people jumping up and down about heavy metals, fish, etc. Wheal Jane did a lot to equate orange water with horrible pollution. I think this is a bit of an over estimate and ochre itself isn't a bad thing (apart from reducing the fish's visibility so they crash into things/each other.
Jane has so much acidity that heavy metals are in solution as their sulphates. Contrary to what was said on the news, they were not precipitated, but got absorbed into "living stuff" as they do. If they were insoluble, they would have become a part of the sediment and unless they were made soluble (by reacting with acid...anything with an acid stomach eat mud?? ) they would remain out of the food chain. The wash outs of oxides/sulphates would form an equilibrium with the environment and you'd see levels in both living stuff and static stuff constant. Jane buggered this up by releasing a huge amount of salts in solution, along with some orange stuff.
If I go wandering into an ochrey adit and a load of ochre ends up in the river and for sake of argument, will everything have a hard time in the river?
I don't think so and I think the people who do are making the mistake of equating orange water to heavy metals in solution.
Ochre is insoluble and is basically pretty inert hydrated iron oxide. Apart from making things go orange, it's pretty safe. Unless it is diluted with a huge amount of acid mine water, it isn't really a problem.
I agree that a lot of sulphide mines will have low pH and have dissolved toxic stuff, but unless this is in the order of a massive outburst, it isn't really a problem.
Periodically, the local river goes orange for whatever reason and people start getting excited. In a lot of cases, I think ignorance is making a mountain out of a molehill. If the actual data shows the level of metals rising by a significant order, this will be of huge concern, but again, this is only a threat if it's soluble and if it's soluble, it's limited by the amount of water.
It would be interesting to know if river monitoring gubbins work from turbidity and then use the possibility of ochre release as an indicator to do take samples.
Either way, I don't think a bit of orange in the river is anything to get particularly excited about. All the papers I've read on the matter don't seem to fit the observed levels in with what was there before, which in many cases would be significant.
Anyway, too much time on my hands today.