Environmental Engineering Reference
In-Depth Information
Important. characteristics. of. vegetation. for. phytostabilization. include. As.
tolerance.and.low.As.accumulation.in.order.to.restrict.food.chain.transfer..
In.parallel.with.geochemical.studies.on.the.oxidation.and.formation.of.sec-
ondary.minerals.of.sulide.tailings,.the.life.cycle.of.the.vegetation.needs.to.
be.monitored.long.term.to.determine.if.this.strategy.is.sustainable.and.self-
perpetuating;.this.is.rarely.done..In.the.case.of.Stawell.Gold.Mine,.Victorian.
Goldields.of.southeastern.Australia,.early.planning.for.mine.closure.strate-
gies.has.provided.a.unique.opportunity.to.adequately.test.regulatory.cap-
ping.prescriptions.for.tailings.surfaces.prior.to.inal.implementation.
This.chapter.provides.an.overview.of.ecological.and.geochemical.research.
into.rehabilitation.of.sulidic.tailings.undertaken.on.purpose-built.facilities.
at.Stawell.Gold.Mine,.from.May.2001.onward..The.ield.trials.were.preceded.
by.glasshouse.studies.that.indicated.the.rehabilitation.strategies.most.likely.
to.prove.successful..Results.of.these.studies.into.the.growth.of.grasses.and.
eucalypts,.the.inluence.of.
mycorrhizae
.on.growth,.and.the.uptake.of.arsenic.
and.metals.into.plant.tissues.are.not.reported.in.detail.here,.although.their.
relation.to.the.ield.trials.and.implications.for.rehabilitation.are.discussed..
The. experimentation. was. designed. to. test. the. eficacy. of. thin,. permeable.
covers. in. future. rehabilitation. of. a. 100.ha. TSF.. The. trialed. covers,. which.
were. designed. to. provide. a. more. environmentally. sustainable. alternative.
to. the. proscribed. impermeable. cover,. involved. amendment. of. fresh. tail-
ings.with.locally.derived.materials.to.generate.substrates.suitable.for.plant.
growth..Within.the.time.limitations.of.the.ield.studies,.it.is.concluded.that.
cultivation. of. selected. native. Australian. trees. and. grasses. is. practical. on.
sulidic. tailings. at. Stawell. Gold. Mine. after. simple. amendment. of. the. sur-
face,. and. this. may. provide. a. sustainable. vegetative. cover. able. to. restrict.
surface.erosion.and.the.release.of.acidic.drainage,.whilst.imparting.value.to.
the.rehabilitated.land.for.the.local.community.
Background
Environmentally.sound.storage.of.sulide-bearing.tailings.is.a.critical.com-
ponent.of.sustainable.gold.mining.in.the.Victorian.Goldields,.where.the.gen-
eration.of.acid.mine.drainage.(AMD).containing.arsenic.and.heavy.metals.in.
solution.may.seriously.affect.groundwater.and.the.surface.environment.in.a.
region.of.competing.land.use..Capping.of.sulidic.tailings.with.an.imperme-
able.cover.is.frequently.proscribed.for.mine.closure.to.avert. such.environ-
mental.impacts..This.may.be.dificult.to.engineer.for.large.volume.tailings.
and. is. prohibitively. expensive. where. natural. impermeable. materials. (e.g.,.
clays). are. locally. unavailable.. Furthermore,. an. impermeable. cover. makes.
self-sustaining.revegetation.dificult.to.instate.leaving.the.structure.prone.to.
physical.degradation.(e.g.,.stream.gullying).and.restricting.the.possibilities.
for.end.land.use..Whereas.tailings.in.the.Victorian.Goldields.are.commonly.
rich. in. sulides,. they. typically. have. signiicant. acid. neutralizing. capacity.
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