Response to Costerfield Operations: assessment of environmental risks associated with proposed changes to water discharge presented to the ERC, 4 May, 2017

Private Printing

Response to Costerfield Operations: assessment of environmental risks associated with proposed changes to water discharge presented to the ERC, 4 May, 2017.

by

Stephen Blackey

B Journ (Dist.), BA (Journalism) Hons, RMIT University

This document is a privately printed response that has been made freely available to the various Departments and to Mandalay Resources and prepared for presentation to the Environmental Review Committee.

It has been compiled by a professional researcher and journalist in order to provide, amongst other things, a more informed and contemporary view of the prevalence of aquatic life in the Wappentake Creek.

A copy will be lodged with and stored at the Watsonia Public Library; it is available online to facilitate cutting and pasting by the various Departments and Consultancy firms.

Permission to cite the contents in any and all future assessments is absolutely granted. And encouraged.

To assist the compilers of such assessments, please note that the document may be referenced thusly:

Blackey, S. (2017). Response to Costerfield Operations: assessment of environmental risks associated with proposed changes to water discharge. Private Publication/ERC Presentation. 4 May 2017.

Available at: http://costerfieldantimonyissues.blogspot.com/2017/05/response-to-costerfield-operations.html

Things look reasonably encouraging, although the antimony levels are still of some concern; particularly if RO flow ceases (for such foreseeable reasons as have already occurred: plant failure, membrane clogging/replacement, etc.), and evaporation concentrates extant levels further.

It would be more encouraging to see a further lowering of antimony levels in the discharge. To have the proposed discharge maintain the already elevated levels of antimony in the creek caused by discharge to date would not be satisfactory. If levels at SW7 are 0.015mg/L upstream of the discharge point, it would be highly desirable to have them approach and be maintained at such a level below the discharge point in order to achieve and maintain environmental integrity along the whole of the creek's length. A drop from one elevated level to another elevated level (0.086mg/L to 0.058mg/L) does not indicate that this is happening (or is capable of being achieved with discharge at the current levels. It would be logical to assume from these figures that 0.028mg of antimony for every litre of flow is being deposited between these two testing points. This is surely unacceptable.

It is a pity that Aquatica Environmental did not extend their desktop evaluation to consider further, contemporary, “anecdotal” evidence when deeming the levels of aquatic life in the creek. It is quite ridiculous to contend that “only one anecdotal recollection of River Blackfish (Gadopsis marmoratus) occurring inWappentake Creek, circa 1925 (Trueman 2012)” is representative of the persistence of the creek’s aquatic life.

·         The Cochrane family were still taking Blackfish and Redfin from the Wappentake in the 1980s and 90s;

·         Neil Harris used the creek as a source of Redfin in the 1970s and 80s;

·         platypus were observed near the confluence of the Wappentake and Majors Creek in the 1990s; *platypus were also observed further upstream, just below the Cochrane family farmhouse in the tellingly-named "fishing hole"...

·         Colin Leask took fish from the creek at Glen Lea at Easter into the 2000s;

·         turtles/terrapins, yabbies and fish (“footlong Redfin”) were observable (the fish were caught in the early 2000s) at Brian Leehy’s residence;

·         eels were caught there, too;

·         and frogs, chiefly the Eastern Banjo, proliferated in the creek until 2014/15 as per my February 2015 ERCpresentation;

·         in the 1980s and 90s a “swaggie” roamed the length of the Wappentake barrel netting the various waterholes for Blackfish.

(*addition 5/10/17 - further updates will be forthcoming as more research is undertaken... Perhaps the EPA could make an effort, eh...?)

This is surely evidence that the current system of “desktop review” is inadequate. The searching of written records only would indicate that the Wappentake was all but devoid of aquatic life nearly a century ago. And this is a complete misrepresentation that would ordinarily stand in perpetuity because of the desktop review system’s neglecting to explore contemporary anecdotal evidence.

It is hoped that the current document provides a corrective to this lacuna, and that it will encourage a more comprehensive assessment of past conditions in the area in order to establish a more accurate and informed baseline from which to move forward.

It is also simply unacceptable that Joel’s word (from an unreferenced email no less!) on the complete drying out of the creek be used as defining evidence for a “normal year”, rather than the gleaning of anecdotal evidence from locals with a long history in the area, in order to decide on the extent of the creek’s “ephemerality”. With all due respect to Joel, he’s a bit of a newcomer to the area (and, we would say, has arrived “after the fact”) and knows comparatively little about “normal years” in Costerfield.

As little as 12 years ago, as recorded in AGD’s Hydrogeological Review completed by URS in 2005/6, it was noted that a rain event of 34mm caused the creek to maintain flow for a period of several weeks. That is no longer the case. The creek never dried out. That's why people set up grazing properties along it. Even G-MW's figures at Glenlea for the early 80s only recorded a cessation of flow, not a complete drying.

For those who can’t see the actual real creek from their desks – such as Aquatica Environmental – it may seem puzzling to maintain that the creek can be full, but that there is no flow. Farmers along the creek have, at various times created fords across the Wappentake to maintain access to stock and to allow stock to pass from one bank to another. These fords serve to make the creek somewhat resemble a fish ladder; it is a series of descending water holes that, yes, once again, never completely dried out. 

During the drought (1997-2009), Costerfield received around 70% of its “expected” rainfall. The “severity” of the impacts of the drought in the immediate area of the Wappentake Creek was caused, not by a lack of rainfall, but by an unprecedented drying up of the creek at that time, which necessitated for the first time ever the trucking in of water for stock that had always been able to rely on the permanent supply in the creek. Our contention has always been that this indicated a connection between the Regional Basement Aquifer (RBA) and Shallow Alluvial Aquifer (SAA).

For well over a decade now we, as concerned residents and beneficial users of the Wappentake Creek, have been maintaining that the inevitable cone of depression (CoD) caused by dewatering and mining threatened the permanence of the creek. We were dismissed out of hand; there was no way that the CoD extended that far we were continually told by mining and regulatory individuals. The map supplied at the last CRG meeting indicates (by extrapolation only, as AGT couldn't join the dots through lack of relevant data/investigation) that the CoD is nowhere near as narrow in its extent as previously claimed and may indeed stretch as far as Splitters Creek, where it would presumably be truncated by the Black Cat Anticline. (That, according to the legend of the map we were given, a fault line appears to lie directly below the evaporation facility, is probably not relevant here other than to indicate the lack of investigation that has previously taken place in the area... still, a storage facility for toxic mine water built on a fault line... seriously...)

AGT have apparently deemed that there is no connection between the alluvial and basement aquifers. The evidence supplied to the CRG was far from convincing to me. The graph provided displays levels at GN14 & GN15 – bores located right in the middle of the mine site where the extensive reapplication of water for mining (i.e. dust suppression) purposes has always taken place. Regardless of the possible impact of this “rewatering”, no monitoring of these two aquifers has taken place in the area we have always claimed has been impacted: downstream in the Wappentake valley; this is the very area into which we may now “assume” the CoD extends.

I note that, according to the levels of these paired bores recorded in that graph – in spite of “pre-production dewatering” during the months preceding December 2005 to a depth of 16 metres – that the Regional Basement Aquifer RBA was at a higher level than the SAA. I indicated at the CRG meeting my perception of the “echoing” of rainfall effects on these aquifers as indicated by the comparable fluctuations in levels recorded on the graph. Such echoing, and the seemingly overlying nature of the RBA with respect to the SAA, hint at a connection of some sort between these two aquifers at some point in the Wappentake valley.

I was informed that these “echoes” are actually recharge of the RBA from rainfall in surrounding areas. It is AGT’s contention that water from a Managed Aquifer Recharge exercise would take approximately 20 years to return to the mine. Given the close correlation of the various fluctuations in water levels in the two aquifers is manifest after just 6 months, it must be asked just how close this recharge area (or this connection) actually is.

That the SAA does not appear to have declined in levels to match the “severe drought conditions” claimed to have impacted on the surface waters, seems to indicate one or both of two things: first, that the drought was nowhere near as severe in its impacts on surface waters in Costerfield as have been claimed (and this is noted above), and second, that there is a connection between these aquifers such that the SAA levels are sustained by the RBA.

This would confirm the observations recorded in the 7-page letter that inadequately served as an “Initial Hydrogeological Investigation” in December 2005, but in which URS declared that:

Groundwater is likely to provide a base flow component to the Wappentake, illustrated by two factors:
1. Wappentake flows at most times of the year; and
2. Water quality indicates a higher Total Dissolved Solids compared with other surface waters, and a similar type to basement groundwater.

We were told that the things we were observing (the drying creek) couldn’t have been caused by things that were undeniably happening (CoD) because those things didn’t happen that far away. That those things now actually do seem to be happening that far away should give one pause for thought regarding the validity and veracity of the claims we have been making.

I raised the matter of the possible “overlaying” of CoDs from previous mining endeavours at the last CRG Meeting. That the current CoD extends to the Costerfield Hall could be viewed in light of the recent re-appearance of a 200-foot shaft at that point. It should come under consideration that previous ingress, egress and regress of water through dewatering exercises may serve to exaggerate the drawdown effect of the current expansive and expanding CoD.

And all of this is testament to the intricate entwinement of environmental and groundwater systems in Costerfield and would seemingly have telling implications for the proposed Managed Aquifer Recharge project currently under consideration.