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BMG
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Location: La Paz / Bahia Asunci�n / Away from home
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I have read that the cyanide left in the tailings can be safely neutralized with a hydrogen peroxide solution.
I think the world is run by C- students.
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gnukid
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More good news from the Gold Mining Industry
http://www.cyanidecode.org/cyanide_environmental.php
"There is no evidence that chronic cyanide exposure has teratogenic, mutagenic or carcinogenic effects."
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gnukid
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Yep the problems I see with gold mining are the movement of all that soil and the remaining cyanide tailings, possibly noise and traffic should be
considered. They usually claim they will move the soll back so what about cleaning up the tailings...
BMG mentions a technique with hydrogen peroxide to neutralize the cyanide tailings and there are other common methods.
http://www.epa.gov/osw/nonhaz/industrial/special/mining/tech...
pg4
"There are three fundamental approaches to the decommissioning of cyanide-contaminated ore heaps. The first is to leave the heap alone and allow the
cyanide to degrade, perhaps slowly, but without any human intervention. The second is to dismantle the heap and treat the ore in smaller batches.
This approach may be necessary when sections of the heap have become impermeable or when it is desired to reclaim the leach pad area for other uses.
The third approach is to rinse the heap to flush out cyanide, with the rinse solution then being treated by any of the methods described below. Ore
heaps may be rinsed with fresh water or with recycled rinse water that has been treated so that it contains little cyanide. The rinse medium may or
may not contain chemicals designed to oxidize the residual cyanide
as it trickles through the heap. "
The hydrogen peroxide can only be used where a surplus of rinse water is available and is therefore not used in arid regions. It appears the gold
mining process uses a great deal of water and the clean-up even more.
"Mines using cyanide heap leaching will already have equipment available to supply rinse solution. The same system used to apply the cyanide solution
can be used for rinsing of the heap. At Echo Bay's Borealis Mine in Nevada, the heaps were rinsed at a rate of about 0.005 gals/min/ft (Schafer and
Associates 1991b) using2 Rainbird sprinklers. At Brohm Mining's Gilt Edge on-off heap leach operation in South Dakota, a cyanide neutralization
solution containing hydrogen peroxide has been applied at a rate of 0.0043 gal/min/ft (Damon,2 Smith, and Mudder 1992). Rinsing also may be
accomplished, or enhanced, by natural precipitation; some facilities have included precipitation as part of their detoxification plans (WGA 1991b).
However, many cyanide heap leach operations are located in arid areas of the western United States where precipitation rates wouldn't be sufficient to
be a source of rinse water."
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mtgoat666
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Posts: 18385
Registered: 9-16-2006
Location: San Diego
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Mood: Hot n spicy
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| Quote: | Originally posted by gnukid
Yep the problems I see with gold mining are the movement of all that soil and the remaining cyanide tailings, possibly noise and traffic should be
considered. They usually claim they will move the soll back so what about cleaning up the tailings...
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newkid:
potential impacts are noise, traffic, visual, air emissions, release to surface water (chemical or sediment), chemical release to groundwater,
groundwater degradation or aquifer overdraft, increase or decrease of surface water flows, habitat loss, etc., etc.,
in USA current regulations generally require mine operators to post financial assurances to ensure funds are available for mine closure and land
reclamation,... doubt that happens in Mex, but maybe it could,...
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