Questions for SirenGold

From: samscreek@gmx.com <samscreek@gmx.com>
Sent: Monday, July 8, 2024 6:01 PM
To: Paul Angus <paul.angus@arcltd.co.nz>
Subject: Questions from Golden Bay community

Hello Paul,

Please see the attached pdf document with questions from members of the Golden Bay community.

Kind regards,

Andrew Yuill.

Questions:

1 * Ownership and regulation*
We understand Siren would be at liberty to sell its consents to another company at
any time either before or during the mining operation. If it does so, what level of
control would Siren (or any other body) have over the kind of process used once
Siren has handed the consents over? Will consents issued under the Fast Track
scheme be for a specific process?
You said that Siren is definitely not planning to use cyanide extraction in Golden Bay.
Instead it is planning a flotation concentrate plant which will put 95% of the sulphide and the gold into a concentrate which will then be shipped offshore. We note though, that Federation Mining subsequently changed its consent to include cyanide-
based extraction at its Snowy River mine. Can you rule out that Siren or any company it sells on the consents to will ever use cyanide extraction in Golden Bay, or does that remain a possibility?
It appears that exporting the concentrate is an expensive operation; what is the
economic case for doing so, and which country will the flotation concentrate be shipped to?
If the gold is exported as a concentrate, what regulatory oversight will the NZ
government have regarding the quantity of gold it contains, for royalty purposes?
In your radio interview you described uncertainty about the eventual shape of mining
operation, even on the key matter of whether an open pit will be created. Yet you
also expect Siren will apply for a mining licence around September this year. In view of the uncertainty around such central aspects, how will the expert panel under fast-
track will be in a position to assess the likely effects of Siren’s proposal?

2 *Flotation Process & Waste*
What chemicals are used in the flotation process? (PAX, frother, copper sulphate, flocculant, lead nitrate?)
Noting that the only filtration/treatment of the flotation waste is usually mechanical
filtration of particulates, what will happen to the other chemicals added to the
flotation water? Is there any chemical treatment to render these harmless?
What levels of dissolved arsenic will there be in the dewatering liquid from the
flotation tailings cake-making process?
As the pH of the flotation process will be optimised for maximum gold extraction and
minimum dissolution of arsenic, it appears there is still likely to be a level of
dissolved arsenic in the waste water. Is this so, and how will it be managed?

3 *Waste Rock Stack*
Can you describe the process used to contain the dry flotation tailings (potentially
arsenic generating (PAG) waste)?
What kind of membrane is used to prevent leaching from the dry tailings if they go
into the waste rock stack (WRS)? What testing has been done on the lifespan of
such membranes?
Does the (WRS) have under-drainage? Where does the liquid that leaches from the
stack go? What treatment is applied before discharge?
Where is it discharged?
What will be the process for leach liquid from the WRS on closure of the mine, once
the process water ponds are backfilled?
Noting that the stability of the tailings is affected at 40% saturation, how will the
company prevent the dry tailings from saturation with water given the WRS is highly
permeable and local rainfall is around 2 metres per year?
Given that acidification over time is common (which would allow As to dissolve), how
will the company prevent acidification of the dry tailings over time, particularly after
closure?
How long will it be necessary to keep the WRS isolated from the surrounding
environment, and how will this be achieved reliably, despite the region’s high rainfall
and earthquakes? What experience does Siren have in these matters?
Is Siren Gold aware that the Takaka Valley is the emergency zone should the Cobb
Dam fail? What provisions will be made to the WRS to ensure that a deluge of water
from the Cobb Dam does not wash the PAG waste into the waterways and ocean?

4 *Backfill into the Mine*
Will any of the removed material be put back in the mine as backfill paste? If so,
then what? How will this be stabilised?
When the groundwater returns to natural levels after closure of the mine, how will the
company deal with seepage of any backfill paste once the ground water levels are
higher than the mine entrance?

5 *Aquatic Life*
What level of arsenic contaminant does a typical consent allow to be discharged into
a waterway? What is the impact of this concentration of arsenic on aquatic life?

6 *Noise*
Given that the crusher and mill likely produce 115dB of noise, day and night, how will
the company ensure that the local area, which is a naturally quiet environment,
remains so?

Response from SirenGold

Hi Andrew

As I said in the radio interview, we are largely still in the exploration phase and have not completed any design work so can’t answer these questions.

Regards Paul