21 August 2012
of the Legislative Council
FINCH (Question) - Madam
President, I ask the Leader:
(1) When will the government repay
the former Beaconsfield Gold Mine operator, BCD, its environmental
bond of more than $2 million?
How will the remediation measures at the mine be assessed for the
(3) What contingency plans are in
place to protect the people of Beaconsfield for any groundwater
contamination from cyanide and arsenic, due to the placement of toxic
tailings in the mine?
(4) Does the government have faith
in the statement by BCD that the Beaconsfield mine is a depleted
resource, given some estimates that suggest that the Beaconsfield
mine still contains the largest and the highest-grade gold resource
FARRELL - I thank the
member for Rosevears for his questions. The answer to part 1: the
security deposits for mining lease ML1767P/M BCD Operations Pty Ltd
Beaconsfield will not be returned to the company until all
rehabilitation obligations have been met by the lessee. This is
expected to take a number of years.
2: An assessment as to whether the rehabilitation obligations have
been met will be made against the agreed rehabilitation criteria as
set out in the approved Decommissioning and Rehabilitation Plan, the
DRP, for the site. This process will be undertaken jointly by the
Environment Protection Authority and Mineral Resources Tasmania.
3: Leaving tailings in surface dams does not result in greater
environmental benefits for protection than deep underground disposal.
The sequestration of tailings deep within the mine has been
determined to be the lowest risk option for long-term storage of the
material. The Beaconsfield mine has a cyanide destruction unit. The
Environmental Protection Agency will require destruction of cyanide
to very low levels prior to discharge to the mine and the mine air
will be monitored for hydrogen cyanide levels. No tailings will be
deposited above the 375 metre level, the depth of the historic mine
workings. Arsenic that was present in the ore taken from the mine
will be in the form of stable ferric arsenate in the tailings as per
accepted best practice for managing arsenic in the gold industry. In
the time between sequestration of the tailings and the mine void
flooding to the near surface groundwater aquifer, any residual
cyanide will have to be detoxified by bacteria lost to atmosphere as
hydrogen cyanide and/or complex with iron that is present in the
the mine is flooded there will be more than 355 metres of fresh water
overlying the denser seawater pumped in with the tailings, ensuring
density separation of the waters. Any residual metal sulphides and
base metal hydroxides in the tailings will remain insoluble, given
the alkalinity provided by the seawater, carbonate minerals in the
tailings and mine water. Subaqueous disposal of sulphides is accepted
practice in the mining industry.
Finch - Have you got any
FARRELL - Not quite, no.
I am just so pleased I did grade 10 chemistry.
government is satisfied that on review of the economics, geology and
engineering complexities, the decision for BCD to close is
substantiated. Closure planning is a complex scientific and
engineering planning exercise with lots of big words, which has been
undertaken transparently with the relevant state government bodies.