What follows is the first installment of an ongoing series of investigative explorations of the permitting and regulatory attention paid to mining operations in Costerfield, a farming and mining town in central Victoria, Australia.
The accumulating evidence shows that the mine there has been systematically (and probably systemically) under-regulated and over-facilitated to the point where a 'perfect storm' of complacency and arrogance has resulted in a threat to the public health.
But they all should have known.
Because it had happened before.
The accumulating evidence shows that the mine there has been systematically (and probably systemically) under-regulated and over-facilitated to the point where a 'perfect storm' of complacency and arrogance has resulted in a threat to the public health.
But they all should have known.
Because it had happened before.
***
From the Environmental Review Committee Report, March 2006
3 Air Quality
3.1 Respirable Particulates (PM10)
The Approved Work Plan for Mining
Licence 4644 includes the following:
During the first
weeks of construction and mining of the open pit measurements of the
concentration of PM10 particulates will be measured at the three
closest occupied residences not owned by AGD on each day operations are being
conducted.
The daily
measurement frequency will be continued until a consistent compliance of the
prescribed limits has been demonstrated after which the frequency of
measurement will be reviewed.
Measurement of PM10
concentrations have been made using a DustTrak Model 8520 Aerosol Monitor. This
device draws in an air stream through a sizing nozzle and uses light scattering
to measure the concentration of particles in the air stream.
Initially the DustTrak was used to
provide minute-by-minute measurements of the PM10 concentration in
the air outside the AGD office on the Heathcote Nagambie Road to obtain an
indication of the character of the air quality in regard to PM10 concentration.
The results obtained are illustrated in figures 3.1 to 3.10 that show plots of
1-minute average PM10 concentration vs time for 24-hour periods,
while table 1 summarises the results obtained.
The following observations can be
made from figures 3.1 to 3.10 and table 1:
·
While the PM10 concentration is
highly variable during the day time it is more consistent and significantly
lower during the night and early morning.
·
During the day-time short term peaks in the PM10
concentrations are common and significant in magnitude.
·
Despite the occurrence of significant short-term
peaks the 24-hour average remained well below what is considered and
appropriate limit, 50ug/m3
·
There is no significant difference in PM10
concentrations on days in which construction was performed and the remainder of
the period.
While the appropriate limit was
set as a 24-hour average, useful monitoring for guiding the construction
activity must be done on a shorter term basis. To use such monitoring results
to test compliance it is necessary to express the 24-hour limit in terms of a
shorter time frame. The EPA approved dispersions model AUSPLUME uses the
following power law expression to determine short-term peak concentrations from
longer-term mean concentrations.
[The formula is provided but we're still to scan it properly for posting. Soon. See info on the AUSPLUME formula's misapplication in Costerfield here.]
The consistent compliance at all locations other than Location 1 for the entire period, the fact that consistent compliance at Location 1 had been achieved for a considerable time and the knowledge that the level of activity on the site has passed its peak, led to the view that consistent compliance had been demonstrated and monitoring was discontinued.
[The formula is provided but we're still to scan it properly for posting. Soon. See info on the AUSPLUME formula's misapplication in Costerfield here.]
The consistent compliance at all locations other than Location 1 for the entire period, the fact that consistent compliance at Location 1 had been achieved for a considerable time and the knowledge that the level of activity on the site has passed its peak, led to the view that consistent compliance had been demonstrated and monitoring was discontinued.
***
From the ERC Minutes 8 March 2006
6.2 Air Quality
6.2.1 Respirable Particles (PM10)
6.2.1 Respirable Particles (PM10)
Daily
measurements of PM10 concentrations were taken at six locations.
Results show a high degree of compliance with the prescribed limit and as a
result of this compliance and the knowledge that on-site dust generating
activity had passed its peak, this monitoring was discontinued on the 13th
of February 2006. [!!!]
[Local
resident ERC member] B** stated his view that the period over which monitoring
was conducted was not favourable to dust generation and dispersion due to the
rainfall that had occurred prior to [5mm
on 2 January] and during the period [13mm
on 11 January] and the wind had not been in the direction of his house. He
indicated that he believed monitoring should continue.
Colin Burns [AGD]
stated that observation on site indicated that the conditions were in fact
extremely favourable for dust generation and that the reason for the effective
control of the dust, as indicated by the results of the monitoring was the
control actions taken. He also indicated that the level of potentially dust
generating activity in the future would be of the order of one tenth of that
during the peak of construction activity and as a result it is safe to conclude
that compliance will continue to be achieved without further monitoring.
Colin
Thornton [DPI] stated that the procedure that had been adopted of testing compliance
until on-going compliance could be assumed was appropriate.
Colin
Thornton asked if the EPA had expressed a view in regard to the need for on
going [sic] monitoring of PM10 concentrations and he was advised
that, while they had not, it was expected that they would in the near future.
Colin Thornton indicated that the EPA view would be crucial in determining
whether further monitoring would be required.
***
And so, after conducting 10 to 30-minute testing in six locations and using a handy power calculation to extrapolate the results to cover 24-hour periods across the whole site, for less than a fortnight, during which time nearly 20mm of rain fell, leading the mine's representative to conclude that conditions had been "extremely favourable" (For whom? one wonders), particulate testing was ended and never reinstated. So much for a “review”.
ot been made available to the ERC.
Below
are two photographs of the Augusta site. The first was taken circa 2005-6 when
respirable dust monitoring ceased, while the second is a Google Maps image from
2014. In order to provide a sense of scale and context, the same building on
each picture has been indicated with a red ‘x’.
Extensive aboveground works have also been conducted just over the road at the Brunswick Pit, the Bombay Dam and the new expansion
into the Cuffley Lode. All done without respirable particulate monitoring.
Eight years of aboveground construction during a dry and
dusty drought period in a location that has been renowned – apparently in government circles only,
though – no one bothers to tell the community – since 1998 as a place
with a recognised “naturally occurring health issue”, and no one thought it
might be an idea to check the respirable dust levels.
***
The reader will have observed, in the above photos, the set
of evaporation dams onsite at Augusta. The development of dams at Costerfield
is quite a story in itself.
The original Planning Permit No. 2248 decreed that tailings
dam permeability for the site be “not greater than 10-6 cm/s over a thickness
of not less than 300mm”. It should be noted here that 10-6 cm/s (cm = m-2 so 10-6-2 m/s) is the equivalent of 10-8
m/s.
[The permeability - or hydraulic conductivity - of a material, in this case clay, is, in essence the rate at which water passes through it. The smaller the number - which here, because we are using negative powers of 10, is the higher number to which 10 is raised - the slower the rate. 10-9 m/s is slower than 10-8 m/s. Slower is better.]
[The permeability - or hydraulic conductivity - of a material, in this case clay, is, in essence the rate at which water passes through it. The smaller the number - which here, because we are using negative powers of 10, is the higher number to which 10 is raised - the slower the rate. 10-9 m/s is slower than 10-8 m/s. Slower is better.]
According to the June 15, 2005, Environmental Management Report Accompanying the Application for
Proposed Establishment and Operation of Open Pit Gold/Antimony Mine at
Costerfield, co-authored by Greg Speirs for CoGB Council:
[Condition] 7. The Groundwater
Evaporation Ponds must be constructed with a clay liner (or similar impervious
material) to achieve a hydraulic conductivity less than 1 x 10-9 m/s to prevent
seepage. The clay liner should be constructed in three separate layers, each
200-250mm thick.
This is a restatement and confirmation of the 2003 Permit
for an Underground Mine (DM/753/03), which reads identically at condition 7,
having already been confirmed at the December 2003 Ordinary Meeting to discuss
the application for the Permit. The Conclusion of the Environment Management
Reports for that Meeting contains, once again at condition 7, the requirement
for a hydraulic conductivity less
than 10-9 m/s.
A file note appended to this permit discusses a site meeting that took place at Costerfield on 4 March,
2003. Representatives from AGD, Bendigo Council, EPA and the DPI were in
attendance. According to the note:
The general outline of the WP/WPV
was reviewed and later a site inspection of the effected [sic] area was made. AGD made it clear that some revision of the
proposed works would take place as more info came to hand (including possible
movement of the portal position), but that the substance of the proposal would
not change.
In particular I questioned EPA
with regard to the use of paste fill underground (the EPA have no problems with
this concept, and it does not require an EPA licence) and the proposed
evaporation ponds (there will need to be more detail about acceptable liners,
but otherwise OK).
A 14 January, 2004 copy of this Permit from Bendigo Council
still requires 10-9 m/s.
Nothing changed for two years. In fact, a further copy of
the Permit (DM/253/2005) allowing the Establishment and Operation of Open Pit Gold/Antimony
Mine received from Bendigo Council and dated as late as 11 August, 2005, also
contains the same condition 7.
In February 2005, however, the tune had begun to change
regarding the construction of the dams and the “acceptability of liners”. One wonders, once again, for whom the “acceptability”
was intended. The Work Plan Variation to MIN 4644 document, at 4.6.2.3 – Evaporation Pond, makes the
following observations.
While the lining of the internal
walls of the embankment and the floor of the pond will provide some resistance
to seepage, its main purpose is to provide a suitable surface for the
installation of a geomembrane liner. The low permeability of this liner will be
such that the resistance to seepage will be greater than would be provided by a
clay liner with the specifications defined in Planning Permit DM/753/03.
From the point of view of planning
considerations the evaporation pond as described above is considered to be in
general accordance with the original proposal for its construction and use are
provided by Planning Permit DM/753/03.
This is not “more detail”; this is a complete subversion of
the Planning Permit’s intents and conditions.
Is it really the case that a geomembrane liner on a clay
wall can necessarily provide the same (or less) hydraulic conductivity as a clay liner
constructed in three successive lifts of between 200 and 250mm to a
specification of 10-9 m/s? Clay liners mitigate the possibility of a
single catastrophic spill event – like a tear in a geomembrane liner – by
reason of their compacted and multi-layered construction.
Was the installation of this liner really “in general
accordance with the original proposal”? The original condition 7 requires
emphatically "construction" of the dam with “a clay liner (or similar impervious material) to achieve a hydraulic
conductivity less than 1 x 10-9 m/s to prevent seepage”. The dam's clay liner was to be "constructed" to prevent seepage,
not to “provide a suitable surface for the installation of a geomembrane
layer”.
In any case the evaporation ponds were constructed to these
altered – and very arguably lesser – specifications.
And from this time on, the hydraulic conductivity
requirements for the site fell from 10-9 to 10-8 m/s. It
would appear that a reason for this lowering of standards was to accommodate
the fact that the construction from local materials has been made difficult
because of the lack of “uniformity of these layers” of “alluvial sediments,
clay, grit and clay [sic]”. Apparently there was lots of clay.
Oddly though, in the 15 June, 2005, Environmental Management
Report cited above, condition 7 requiring 10-9 m/s is still present for
DM/253/2005, the Open Pit Permit.
In the 17 years since the first iterations of this present
mine, the requirements for the hydraulic conductivity to prevent seepage from
dams and water facilities have not risen. Seventeen
years. When a standard over and above the DPI standard was recommended
in 2003-2006, DPI and Council regulators undermined the requirement and
instated a standard that fails to meet the requirements under South Australian EPA regulations and under Western Australian Department of Water standards and
only meets the minimum standard for Victoria.
In May 2014, the Victorian Civil and Administrative Tribunal (VCAT)
recommended a level of permeability of no greater than 10-9 m/s AND
the use of an HDPE (High-Density Polyethylene) liner to mitigate seepage from
the Splitters Creek Evaporative Facility. But the permit for the construction
of the rises of the Brunswick Pit and the Bombay Dam were quickly approved in
November of 2013 at the lesser DPI 2004 standard and WITHOUT an HDPE liner.
(Why so quickly? Why not wait for the VCAT decision?)
For clarity in what follows – the state of play in Victoria:
DPI – Management of
Tailings Storage Facilities - 2004
Seepage containment
For
those TSFs storing contaminated tailings, the standard level of containment
should be at least equivalent to 0.6 metre of clay with permeability no greater
than 10-8 m/sec.
Why do Victorians not deserve the same best practice that
prevails elsewhere in Australia? It says “at least” in this document; why was a
greater level not attempted?
From the SA EPA:
If the depth of wastewater
exceeds 2 m, or is associated with a licensed activity, a lagoon may be subject
to more stringent requirements—including seepage measurement and monitoring—as
part of development approval and/or licensing processes.
Material selection
The material used as a clay liner should be a well graded clay of medium plasticity. It should be free of topsoil, tree roots and organic matter, and compacted to achieve 90–95% maximum dry density, determined in accordance with Method 5.1.1 of Australian Standard 1289. When suitable clay materials are not readily available a synthetic liner should be used to ensure effective quality control.
Permeability
For a lagoon depth of up to 2 m, the compacted clay liner should have a minimum thickness of 300 mm and should be constructed to achieve a coefficient permeability of less than 1 x 10-9 ms-1. Lagoons deeper than 2 m should be designed and constructed by appropriately qualified and experienced specialists, to ensure that adequate protection from pollution is provided.
Synthetic liners
Synthetic liners include PVC (polyvinyl chloride) or HDPE (high-density polyethylene). The issues of permeability, volume, embankments, and possible reactions, as listed above for natural clay linings, must also be considered for synthetic liners. Other considerations for a suitable synthetic liner include the following:
Material selection
The material used as a clay liner should be a well graded clay of medium plasticity. It should be free of topsoil, tree roots and organic matter, and compacted to achieve 90–95% maximum dry density, determined in accordance with Method 5.1.1 of Australian Standard 1289. When suitable clay materials are not readily available a synthetic liner should be used to ensure effective quality control.
Permeability
For a lagoon depth of up to 2 m, the compacted clay liner should have a minimum thickness of 300 mm and should be constructed to achieve a coefficient permeability of less than 1 x 10-9 ms-1. Lagoons deeper than 2 m should be designed and constructed by appropriately qualified and experienced specialists, to ensure that adequate protection from pollution is provided.
Synthetic liners
Synthetic liners include PVC (polyvinyl chloride) or HDPE (high-density polyethylene). The issues of permeability, volume, embankments, and possible reactions, as listed above for natural clay linings, must also be considered for synthetic liners. Other considerations for a suitable synthetic liner include the following:
·
The lagoon earthworks must be designed and
constructed to meet the specifications and requirements of the synthetic liner
manufacturer.
·
For a lagoon depth of up to 2 m, use a membrane
at least 1 mm thick and with a coefficient of permeability of less than 2 x 10-10
ms-1. Lagoons deeper than 2 m should be designed and constructed by
appropriately qualified and experienced specialists to ensure that adequate
protection from pollution is provided.
***
Here it can be seen that in South Australia, if a
geomembrane liner is to be used then the hydraulic conductivity is to be
greater than that required by a clay liner on its own. And if the depth of water is to be greater than 2 metres then even
more stringent conditions apply.
The Government of Western Australia – which knows a little
bit about mining one would hazard to guess – is just as stringent in its
requirements. The WA Department of Water’s Water Quality Protection Note 27 covering ‘Liners for containing pollutants,
using engineered soils’ similarly requires 10-9 m/s up to 2m depth
and then increased standards thereafter. Note 26 for the use of 'synthetic membranes' requires their hydraulic conductivity to be less than that of the
clay/soil liners in line with the SA EPA at 2 x 10-10 m/s.
What has been happening at Costerfield?
Why is the mine at Costerfield being built to the lowest
standards that the regulators are possibly able to impose?
Why is Victorian Best Practice not in line with other states’ requirements?
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