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MINES AIM TO TURN POLLUTION INTO
PROFIT
Business Report [ 30th of September 2009]
By INGI SALGADO
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Acid mine drainage is a ticking bomb
requiring a concerted response UK firm hopes to treat and sell
water before it leaks.
Gold mines are racing against the clock to prevent a looming
decant of highly polluted water from underground voids caused by
more than a century of mining.
Their method: collaboration. No single firm has the resources to
deal with the magnitude of problems resulting from acid mine
drainage (AMD).
Their ambition: to secure an offtake agreement with Rand Water.
They hope to convince the utility by year end that vast
quantities of water from unused mines can be treated to potable
standards by removing the heavy metals and sulphates released
when exposed ore comes into contact with water and oxygen in a
process known as AMD. In this way, the project could be
propelled towards a measure of self-sustainability.
A sustainable solution is critical, because - in the words of
Mariette Liefferink, the chief executive of the non-governmental
organisation Federation for a Sustainable Environment - the
issue will continue not for decades but for centuries.
"In 120 years of gold mining, 120 gold mines have extracted 43
500 tons of gold and 73 000 tons of uranium, but they have left
South Africa with a legacy of 410km178 of tailings dams and 6
billion tons of iron pyrite. There will always be AMD seepage,"
Liefferink says.
According to a paper on mine water pollution commissioned by the
Department of Environmental Affairs last year, AMD threatens the
country's scarce water resources, human health and food security
in mining areas. There are no easy solutions, but AMD does
present "an opportunity to provide usable water through
appropriate treatment technologies", the paper says.
Time trials
After 1996, when the first predictions were m ade concerning
decant from the western Witwatersrand basin, some gold producers
tinkered with technologies to deal with the problem but did not
explore them to commercialisation. And so when decant started in
2002, neither the mines nor the government were prepared to deal
with the scale of the problem.
At the time, the industry responded by pumping water into the
Robertson Lake in Randfontein. Today, that body of water
contains uranium levels of 16 milligrams per litre, compared
with regulatory limits of 0.07 milligrams per litre of drinking
water and 0.01 milligrams per litre of water used for
irrigation. The lake is the source of the Tweelopiespruit, which
ultimately flows into the Limpopo River catchment.
These days, mines are partially treating the water after
channelling it into a lined dam. Discharged into the
Tweelopiespruit, it is contaminating boreholes downstream. Apart
from the safety and environmental hazards, there are concerns
for the structural integrity of the Johannesburg city centre and
the N14 as AMD depletes underground dolomite.
The western basin is decanting at a daily rate of 15 megalitres.
At the mines' treatment works, the water is neutralised by
adding lime. The heavy metals form a complex solid. The water is
pH neutral but elevated sulphate levels remain. In the meantime,
the Department of Water and Environmental Affairs has issued a
directive limiting sulphate levels of the mines' discharged
water, effective at the end of October.
"To get sulphate levels below 600 parts per million, you need
more technology," says Jaco Schoeman, the head of Western
Utilities Corporation (WUC), a wholly-owned subsidiary of
London-listed Watermark Global, commissioned by gold mining
firms to develop a plan to treat AMD in the western, central and
eastern basins.
The group's short-term plan is to pump water in the western
basin via a pipeline to the central basin, which is itself
predicted to decant at a rate of 60 megalitres a day when it
floods in about two years' time. The eastern basin is forecast
to decant at 80 megalitres a day in about two years, seeping out
the ground at the Nigel taxi rank.
Over the medium term, WUC plans to treat some of the water to
industrial quality for use by the gold mines. For every ton of
ore mined, they require about a ton of water.
Second, WUC hopes to convert up to 100 megalitres a day to
drinking water for sale to Rand Water, using a five-step alkali
barium calcium process developed by the CSIR. This involves free
acid neutralisation, heavy metal precipitation, removal of
magnesium and sulphates, filtration and disinfection.
"We've run two pilot plants for eight months," says Schoeman.
The results suggest that, provided the process is performed
daily, water is produced to standards set by the SA National
Accreditation System and the SA Bureau of Standards.
WUC is not the only company offering technological solutions for
the gold mines' AMD headache, but it is the only project to have
secured offshore funding. The mining industry has donated
infrastructure to WUC and entered into a memorandum of
understanding, while the Development Bank of Southern Africa has
granted a R10 million non-recourse loan for a bankable
feasibility study.
This gives WUC a time advantage in dealing with what Schoeman
labels an imminent environmental disaster spreading outwards
from Gauteng.
He says the project depends on securing a positive record of
decision for its environmental impact assessment, a positive
decision on an integrated water use licence, and an offtake
agreement with Rand Water.
The water utility won't comment, but Schoeman says there are
three outstanding issues: the utility's satisfaction with
quality standards, agreeing on a price and formal state
approval.
"On assumption we get approvals this year, we hope to start
construction in the first quarter of 2010. We see a 12-month
construction period and a three-month ramp-up to the second
quarter of 2011. It's a tight schedule. We can't afford delay."
Urgent understanding
Internal briefing documents seen by Business Report suggest that
high-ranking officials in the Department of Water and
Environmental Affairs understand the urgency of the problem, and
have considered spearheading WUC's projects on a political level
with the government agencies that need to give the project the
go-ahead.
However, they are believed to be fearful of being held
responsible should WUC fail technologically and economically.
There are also concerns that an overseas entity - Watermark
Global - should benefit instead of local communities.
In a written response, the department says it does not have any
special relationship with WUC. Asked whether it would prioritise
the authorisation of WUC's application because of the urgency of
the problem, it said: "These priorities are important to the
department as long as the applicant fulfils the requirements of
the regulator (government)."
Any agreement between Rand Water and WUC would amount to a
business transaction between two entities and the department's
mandate was to regulate and support initiatives from any party
bringing solutions to the problem, it said.
Regulatory issues aside, WUC's bankable feasibility study and
the securing of finance will ultimately determine whether it is
going to walk its talk. The company needs to secure the bulk of
R2 billion required to proceed with the mop-up. The mines have
contributed about a quarter of the amount via existing
infrastructure. The rest must be raised via debt and equity.
Schoeman envisages this will be in the ratio of 75:25.
Markus Reichardt, an independent mining sustainability
consultant and former corporate environmental manager at
AngloGold, advises caution based on past efforts in dealing with
AMD. "It's been tried quite a few times in the past. It's not as
if the big firms haven't thrown money at this. That doesn't mean
WUC can't be the first, but they're treading over the wreckage
of previous projects."
Scheming success
A more successful scheme has been the Emalahleni water
reclamation project in Witbank, initiated by Anglo American and
BHP Billiton in 2007 to set up a central facility for treating
water from underground collieries to potable standards. The
water is sold to the municipality, and the products of the
sludge are used in bricks.
"It's a triple-win solution in the sense that no polluted water
goes into the water resource, communities have access to water
and the department doesn't have to monitor or enforce procedures
because there's proper management of water resources," says
Mikisi Lesufi, the Chamber of Mines executive for environmental
health.
"That kind of model is what WUC is trying to follow," he says.
The big difference is that Emalahleni is not a self-sustaining
project. "There are not a lot of mines able to give the kind of
money that Emalahleni has. Companies need to put in capital
expenditure on a continual basis. They need to have an exit
strategy when the mines close," Lesufi says.
Koos Pretorius, a director at the Federation for a Sustainable
Environment, estimates the Emalahleni treatment plant cost R350m
to build and runs at a loss of R7 per cubic metre, or about R150
000 a day.
"Every 20 years the plant has to be rebuilt but they can't do
the recapitalisation," he says, alleging that one of the mining
houses behind Emalahleni "wouldn't even investigate a
reclamation plant" at a proposed new joint venture colliery near
Belfast.
Another possible shortcoming is the principle that consumers end
up paying for a problem caused by mining firms. Lesufi, however,
says consumers will buy from Rand Water in any case.
"It's simply an opportunity for Rand Water to augment its water
supply. Gauteng is a major centre, mining water is an
opportunity. It's not as if we are fleecing the consumer. We
should be clear Rand Water will not buy water at an exorbitant
price. It's up to WUC to optimise its treatment technology to
meet Rand Water's very strict specifications," he says.
Lesufi concedes that the WUC model "may well have problems, but
it still presents the best opportunity on the table to deal with
the problem".
Barbara Schreiner, who is a practice director in charge of water
strategy at Pegasys, and former deputy director-general in the
old Department of Water Affairs and Forestry, says the WUC model
is an "innovative approach, one of the things we need to look at
more and more". Assuming the numbers are in order, Schreiner
describes it as a "perfectly good response".
Authority action
Either way, all parties agree that to avert a crisis, the
authorities need to act fast.
Otherwise, water shortages could take hold by about 2013 in
Gauteng, Schreiner cautions. "Basically, we're on a pathway to
water shortages unless we cut back significantly on water usage.
Part of the challenge is a lot of industries are using poor
quality water and have to use more water to dilute it. So
requirements increase if quality declines," she says.
In Mpumalanga, AMD from coal mining - both historically and as a
result of new mining applications - threatens the Vaal River
basin, which supplies water to Gauteng.
"The upper Vaal River catchment is relatively unaffected by
mining, but if all applications for mining permits in this
catchment are granted, it is likely the Vaal River will suffer a
similar fate to rivers in the Witbank area, creating serious
water supply problems for the industrial heartland of the
country," says a paper co-authored by Pretorius and Wits
University geology professor Terence McCarthy.
Anthony Turton, a former CSIR scientist who resigned last year
after spilling the beans about an imminent water crisis, says
South Africa is starting to trade off current energy needs with
future food security.
"I've called for a national debate on energy security, food
security and water security. At the moment they are managed as
separate issues. Energy is at the top of the hierarchy of
importance but people don't realise that by securing energy
needs in the short term, in effect they are writing off our
agricultural food security," says Turton, now a professor at the
University of Free State's Centre for Environmental Management.
Turton hopes National Planning Minister Trevor Manuel will
co-ordinate the issue.
Lesufi supports the call for a dialogue on energy, water and
agriculture. "It's a simple issue of land access and the
competing interests of tourism, farming and mining. Each
economic sector has to put its case on a cost-benefit analysis.
If the impact of mining is so bad, that it does not carry South
Africa to sustainability, then... that land use must not be
supplied."
Read article online at
Mining Weekly |
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