Here is our presentation, made to the Committee, regarding the possibility of contaminated water that is causing discolouration and a dearth of frogs in the Wappentake Creek* being sourced from legacy - i.e. historical - tailings and workings along Tin Pot Gully and Tin Pot Gully Creek.
It seemed to go down well.
(* It would now appear that the process responsible for the 'fog' referred to in the linked post may have been sourced from the mine's evaporative misters.)
***
Tin Pot Gully
1. Introduction
In this discussion paper I present some selected historical
facts concerning Tin Pot Gully, and some of the more recent ERC responses.
Problem
Tin Pot Gully was the acknowledged tailings dam for 100
years of mining at Costerfield. History clearly records the numerous furnaces
fuelling cyanide plants and gives some idea of a town with thousands of miners
and their mullock heaps.
Legacy
Bio-indicators are species that can be used to monitor the
health of an environment or ecosystem. There are any number of biological
species whose function, population or status can reveal what degree of
ecosystem or environmental integrity is present.
Residents have noticed, over a long period of time, the
variability of frog presence in the Wappentake Creek. After heavy rains from
the north of the creek (from the direction of Tin Pot Gully) the presence of
frogs would be noticeably diminished. They would return, but their periodic absence
(and/or drop in numbers) was noted.
Frogs were deafening at my bridge over the Wappentake in
Winter/Spring 2013. They were nearly non-existent in 2014.
Grey water in the Wappentake Creek
In August 2014, as the first of the treated water entered
and flowed down Wappentake Creek, the frogs were back. The RO water was clear
but changed to a tea colour as it mixed with the usual creek water.
Since that time, however, the water has flowed a thick grey
colour – as if it had been sourced from a cement works – and the frogs are gone
from the creek. They are still present in numbers in the dams and waterholes on
my property. Just not in the creek.
Similarly coloured grey water can be observed at Glen Lea
and further down the Wappentake as it approaches the Goulburn River. Anecdotal
evidence suggests that there are now no frogs in the creek as far away as eight
kilometres from the discharge point.
Tin Pot Gully Creek originally ran between the Main and
Minerva Shafts in Costerfield, then down Tin Pot Gully, where it became Tin Pot
Gully Channel, implying a man-made waterway. And this would make sense
as Tin Pot Gully Creek/Channel was the chief discharge point for mine water and
treatment water from 1862 to 1975. Workings also took place at a location known as Tin Pot Flat.
Could the discharge of treated water via the 0.5ML/day
Reverse Osmosis plant have saturated and “activated” contaminated soils along Tin
Pot Gully Creek/Channel, so enabling the release of historical mining waste
originally sourced from the historical workings in Costerfield? The water in
Tin Pot Gully Creek under the bridge at the South Costerfield-Graytown Road is
similar in colour to that in the Wappentake Creek.
I would like to draw the committee’s attention to these
possibilities as a primary cause of surface water pollution/contamination in
the Wappentake Creek and would appreciate the committee’s comments at the next
meeting.
2. Recent use of Tin Pot Gully for discharge of RO water
1 August 2013 Q2 ERC Minutes
“The EPA has approved discharge of half a megalitre of
reverse osmosis (RO) treated water into Tin Pot Gully Creek. The RO plant was
commissioned in May and started operating in July. 6.9 megalitres have been
discharged so far and the water has moved approx. 550-600 metres downstream
since the discharge commenced.”
***
7 November 2013 Q3 ERC Minutes
“Andrew Mattiske said treated groundwater permeate
discharged from the RO plant was currently limited to 0.5ML/day, with a total
of 29ML of treated water being discharged into Tin Pot Gully to date. The RO
plant discharge point was moved 500 metres down-stream during this period.”
***
1 May 2014 Q2 ERC Minutes
“The RO plant has discharged 55ML to date into Tin Pot Gully
Creek. Colin Thornton asked if the discharge into Tin Pot Gully had
created any noticeable impacts. Andrew Mattiske replied that photographs and
inspections of the creek line indicate no noticeable changes in the creek.”
[That is, no noticeable change to Tin Pot Gully Creek.]
***
11 May 2014 Resident testing of water of Tin Pot Gully at
South Costerfield-Graytown Rd
6,300ug/L antimony
6,300ug/L => 6.3 mg/L
***
26 June 2014 letter from EPA
That 71 ML had been discharged from the RO plant into Tin
Pot Gully Creek as at 30 May 2014
***
3. Historical use of Tin Pot Gully for the discharge of mine
water
From Costerfield Mine
Site Quarterly Hydrogeological Review,
URS, 5 June, 2006.
Site History
“Gold and antimony were first mined in the Costerfield area
in 1862. Mining of the stibnite-quartz veins, which were mostly confined to the
north striking near-vertical zones, continued intermittently until 1951. During
this period, the main shaft, located at Costerfield, reached a depth of 330m
and included many kilometres of underground working. Water removed from the
mine was discharged directly into Tin Pot Creek (O’Shea, July 1988).
“In 1964, the Brunswick Mine (ML1455) was developed by Mid
East Minerals NL. The mine included a 30m inclined shaft, followed by a 45m vertical
shaft with level development at 44m (O’Shea, July 1988).
“This shaft was deepened to 65m by Forsyth Minerals
Exploration NL. During the operation of the Brunswick Mine, mine water was
discharged into a tributary of Tin Pot Creek under the sanction of a Sludge
Abatement Board. The Brunswick Mine was closed in 1975.”
***
From The Costerfield Auriferous Antimony Veins: Geological Survery of Victoria, Bulletin No. 50, by H. S. Whitelaw, Department of
Mines, 1926.
1862 to 1883 – Main Mine was sunk to six levels at 600 feet.
1905 to 1922 – Main Mine extended to nine levels at 936 feet
below sill.
The “Detail Lease Plan” in Bulletin No. 50 has the Costerfield Main Shaft reaching 1015 feet.
***
“The story goes that, a heavy thunder shower having fallen
the previous evening and washed off the rusty coating that usually discolours
such outcrops, the surface of the “big rock”, as it was called, appeared in the
morning sun as a glittering white mass. Viewing it through the timber of Tin
Pot Gully, from a distance of a quarter of a mile, Youle pronounced the find a “buck”
quartz reef similar to two others on his original claim…” (p. 4)
***
“Encouraged by the successes at Upper Costerfield… W.
Morris, of Heathcote… essayed to locate the southern extension of the reef at
Lower Costerfield (now South Costerfield) about 1 mile away on the southern
side of Tin Pot Flat.” (p. 6)
***
“No special attention has been given to the treatment of the
150,000 tons of tailings (net value £7,500) heaped on the surface, but in the
course of time, the whole of these will be absorbed by their inclusion in
limited quantities (at present 80 per week are thus being treated at a profit
of 1s. per ton) with the ore as trammed from the mine, it having been found by
experiment that owing to a certain amount of oxidisation having taken place the
older sand, per se, is not amenable
to the treatment process now in operation.”
***
“The main shaft… They are all near the source of Tin Pot
Gully Creek, a tributary of Wapentake Creek, a branch of Deegay Ponds Creek
which, flowing easterly, joins the Goulburn River 15 miles distant… very little
alluvial was found in the right-hand branch of Tin Pot Gully which crosses the
reefs between the main and Minerva shafts.”
***
From Beyond the
1850s Gold Rushes: Mining Technology from the 1890s to the Present,
Encyclopaedia of Gold in Australia
“Contributing to the state’s high gold production was the
introduction of a new chemical-based gold treatment process. By 1897, there
were major cyanide works at Tarnagulla, St Arnaud, Stawell, Ballarat, and
Maldon. One of the most stunningly successful introductions of cyanide
processing in Victoria was at Costerfield. After 50 years of unsuccessful
experiments to unlock the gold from the field’s antimony-rich ore, the
application of the cyanide process brought immediate success, and in a decade
or so gold worth £240,000 was recovered.
***
4. Conclusion
It is our understanding that at one point in time, at least
30 cyanide treatment vats were in operation in Costerfield during the
late-1800s and early-1900s. Mine water and the waste from tailings treatment
and other processing operations was discharged down Tin Pot Gully, at various
times, for over a century.
But this is not to suggest that only cyanide should be
considered as a possible contaminant. A full examination of all possibilities that may require a clean
up should be undertaken.
The map in Bulletin
No. 50 displays other historical and legacy operations – piggery, potter –
that took place along Tin Pot Gully that may have resulted in the deposition of
contaminated or toxic material – and it must be emphasised, totally beyond the control of Mandalay
Resources as it may not even be sourced from the mine site – that may be
contributing to the impacts we now observe in the Wappentake Creek.
***
Grey water at Tin Pot Gully Creek next to South Costerfield-Graytown Road
Grey water at Glen Lea
Grey water at bridge on Wappentake Creek
Tea-coloured high-water flow at bridge on Wappentake Creek after rain event
Presentation by Steve Blackey to Costerfield ERC Meeting, February 2015
Afterword:
The grey colour of the water has now been pretty much isolated to the presence of manganese in the water. Manganese is present
The point that should be made here though, is that no one knew there was manganese in the water because no one, not DSDBI, not EPA, not anyone had tested for it. Noticing the increasing discolouration and doing a little research on the Net, a local resident first suggested that manganese may be present. And, after testing by the mine, sure enough, there it was.
The levels of manganese are low; well below Australian Drinking Water Guidelines apparently. But they cause not very aesthetically pleasing results. And the problem may be that Manganese is a precursor to some cyano-bacterias - blue-green algaes - and so may be causing the frogs to hop out elsewhere.
It was always just a little bit after a rain event had washed the evidence away that EPA managed to get down to Wappentake Creek to check out the reports of algal blooms in the creek. Oh but they were blue-green alright.
Don't be confused, though. The suggestion that cyanide may be directly responsible for frog numbers dropping (by cyanide poisoning, for example) is to some extent misleading; because of the name. The "cyan" in cyanide and cyanobacteria is there, not because they are chemically linked or because one "causes" the other, but because they are both blue, cyan being from the Greek for "dark-blue". Most of the cyanide will have broken down by now. It's just not nice having it there.
Oh and cyanide contains Nitrogen... and putting Manganese and Nitrogen together is a good way to end up with cyanobacteria.
Isn't it Dr Pigdon?
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