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Long before the current

resource boom fuelled the

extractive industries, the

mining sector was transformed

by high-tech resources

distributed over exploration,extraction and processing.

This transformation continues

and with the introduction of

green mining technologies,

now encompasses the

environmental aspect too.

There is no inconsistency, as

some people suggest, to the

term green mining and this is

not some short joke like military

intelligence or virtual reality.

There is something that is

surprisingly true within thekernel of clichd oxymoronic

statements but any supposed

paradox in green mining is not

fair considering the practicality

of environmentalism meeting

the extractive industries.

Our love-hate relationship with

things and their real price quite

rationally leads to a bitter sweet

understanding of the cost of

sourcing the resources against

the benefit of consumption, but

the idea of sustainable mining isanything but mutually exclusive.

The basic discontinuity comes

from the idea that modern

mining projects leave behind

disrupted communities,

damaged landscapes, and

polluted water.

Green mining describes

methods by which the waste

produced by mining is

transformed into

environmentally friendly

resources for other uses, leaving

behind healthy ecosystems with

clean water and rehabilitated

landscapes. The four pillars of

green mining are: footprint

reduction, innovation in waste

management, rehabilitation of

mine site and ecosystem risk

management.

The rise of green mining does

not reflect a cultural shift in the

industry, beyond what ishappening across all society, but

is the result of a number of

progressive regulations and

taxes; such as the Quarries Tip

Act, the Waste Mining Directive

(WMD), and the Landfill Levy; all

of which deal with the issue of

waste and define how the

mining industry can be

regulated and methods

improved.

Caterpillar, the construction and

mining equipment manufacturer,has addressed some of these

issues and developed an

innovative engine technology

called ACERT which delivers a

5 per cent improvement in fuel

efficiency, up to 90 per cent

reduction in particulate matter

and 50 per cent reduction in

oxides of nitrogen.

Similarly, the mining giant Vale

plans to cut their carbon

emissions by 20 per cent using a

fuel of 20 per cent biodiesel and

80 per cent diesel in all of their

machines. They expect to save$US 150 million per year in the

process.

No matter how efficient or

clean any mining technology

used, there is usually some

form of remediation needed.

A common example is the

spillage of fuels during normal

operations. On a large mine,

the amount of polluted soil

arising just from this can run

into thousands of tonnes

annually.

Many methods have been used

for remediation but there are

five prominent approaches to

treating hydrocarbon impacted

soil. These are:

Bio-remediation (use of

bacteria)

Encapsulation (use of concrete

or lime to immobilise

contaminate)

Soil washing

Phytoremediation (use of

plants to bio accumulate the

contaminant out of the

ground), and

Thermal

destruction/desorption (use of

heat).

QUARRIES & MINES 2012

PHIL KNEEBONE

REMEDIATION ENVIRONMENTAL ISSUES

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SOIL REMEDIATION SEES

GREEN MININGINNOVATIONPHIL KNEEBONE, MANAGING DIRECTOR, SHIFT SOIL REMEDIATION LLP

Remediation methods and drivers through time

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The main by-products of mining

are tailings, the waste product of

ore-processing facilities, which

contain a high concentration of

heavy metals. These tailings can

be susceptible to erosion or

removal by wind and water,

adding further to problems such

as water contamination.

Electrokinetic remediation hasbeen shown to be successful in

such cases, as it relies on the

application of a low-intensity

direct current through the soil

between ceramic electrodes. This

mobilises charged metal particles

in water causing them to move

toward the electrodes where they

can be collected and treated.

Although heavy metals and petro-

chemicals prove more difficult to

remediate, acid mine drainage

(AMD) is the worst environmental

problem faced by the mining

industry. This is generally treated

with alkaline reagents such as

limestone, lime, soda ash etc.

This in itself is relatively effectivebut can be combined with barrier

technology to produce even

better results. Permeable reactive

barriers enable treatment of

contaminated groundwater by

directing flow through reactive

materials placed in trenches. So

far, a combination of compost,

limestone and recycled steel slag

dusts has been found to be the

most effective but other

treatments/combinations are also

being investigated to determine

their effectiveness.

An example of prevention in the

case of AMD is the Haber Gold

process (HGP is exclusively

owned by US-based Omai Gold

Mines). The process operates by

extracting the gold from its ores

by dissolving the gold into water

using non-toxic chemicals where it

can then be recovered. The key

factor in the success of this

solution is that it does not lead to

the release of heavy metals such

as mercury, cadmium and lead.

While there is ever more

innovative remediation

technologies to address the toxic

or harmful pollutants produced asa result of the mining process, the

problem of inert waste must also

be addressed; while not directly

affecting the environment by

toxic contamination it will

contribute to visual pollution and

leave the site in an inactive state

once closed.

Another use of this recycled

aggregate is a substance called

Plastisoil, created by Naji Khoury.

It is a combination of

polyethylene terephthalate,

which is pulverised and mixed

with soil, blended with a coarse

aggregate and then heated to

create a hard yet non-watertight

substance similar to porous

asphalt. The unique properties

of Plastisoil allow rainwater to

flow completely through and not

run over the surface of the

ground, collecting contaminates

at it goes which then flow into

our rivers.

There are many examples around

the world of effective mine and

quarry regeneration possibly the

most famous in the UK is the

Eden Project but there are

numerous other uses ranging

from heritage and tourismattractions, wildlife habitats,

educational, sport and leisure

facilities, concert venues and

dozens of industrial uses.

The green mining revolution will

continue and increase in pace as

new technologies are developed

and innovations sought and

drawn from the medical, space

and military fields.

Mining, just like other business,

has always been conducted with

sustainability in mind. It is justthat we have now changed our

view of sustainability.

For further information,

visit: www.shiftsoil.co.uk

QUARRIES & MINES 2012

ENVIRONMENTAL ISSUES REMEDIATION

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Offering cost-effective solutions at competitive prices

Acid mine drainage is one of theworst environmental problemsfaced by the mining industry