Talvivaara is implementing several development projects as a result of the gypsum pond leakage investigation conducted by VTT

Stock Exchange Release
Talvivaara Mining Company Plc
29 April 2013


Talvivaara is implementing several development projects as a result of
the gypsum pond leakage investigation conducted by VTT


VTT Technical Research Centre of Finland ("VTT") carried out an independent
investigation, commissioned by the Board of Directors of Talvivaara Mining
Company Plc ("Talvivaara" or the "Company"), on the reasons and circumstances
which led to the gypsum pond leakage in November 2012. The investigation
resulted in several recommendations for corrective and development actions. The
Company had initiated the implementation of the majority of these
recommendations immediately following the leakage in November 2012, and the
Board has requested action plans from the Company's operative management
regarding the remaining recommendations.

Objectives of the investigation

The objectives of VTT's investigation were to study the direct reasons of the
incident and to analyze the root causes leading into the realization of the
risks. Additionally, the investigation included a general risk assessment of
other pond structures. VTT's investigation team consisted of experts on dam and
pond structures, water management, safety culture and management, risk
management and environmental legislation. The Company's Board commissioned the
investigation in order to be able to ensure that similar risks are managed
better in the future and safety at the Company develops to a level consistent
with the standards of sustainable production.

Results of the investigation

VTT's experts state that the original design of gypsum pond section 1 was
vulnerable. The insulating structure of the pond section was a 1.5 mm HDPE
membrane and, based on the knowledge available and authority requirements at the
time, the water conductivity or erosion stability of the soil below had not been
paid sufficient attention to during the design and construction phases. The pond
structure was designed on the presumption that the pond would predominantly
contain relatively solid gypsum waste and any water accumulating in the pond in
conjunction with effluent pumping would be pumped out, due to which the risk of
a major leakage would not exist. However, contrary to original plans, water had
to be stored in the gypsum ponds as the accumulation of water in the area was
more than the Company's 1.3 Mm(3) annual quota for discharging purified waste
waters into the environment. The investigation suggested that in the early years
of operation the water management measures were not sufficiently holistic and
systematic as many other development projects and challenges consumed resources.
Even though the Company implemented several steps to improve the water balance,
especially from late 2011 onwards, all ponds filled up during the 2012 spring
melt and water from the gypsum pond was temporarily pumped into the open pit. A
decision was made to raise the banks of gypsum pond 1 in order to create
additional water storage volume. The elevation was completed at the end of
September, and more than 1 Mm(3) of solution was pumped into the pond before the
leakage in section 1 started on 4 November.

VTT's experts state that small seeps always occur in HDPE membrane structures.
Even small, seeping leakages can start eroding the soil beneath and result in
fracturing of the insulating membrane if the structures beneath the membrane
have not been designed in view of leakages. The likely mechanism resulting in
the leakage in November was such a seeping leakage, which escalated as the
hydraulic pressure increased due to filling up of the pond beyond earlier water
levels. Earlier leakages in the same pond section have also very likely resulted
in latent damages in the pond foundations as water flowed through the soil
beneath the membrane in the pond dam and at the bottom of the pond. Supervised
repairs of the pond had been carried out in 2008 and 2010. The November 2012
leakage started at the point where the 2010 repairs had ended. Due to potential
similar latent damages, VTT's experts identified the wall between gypsum pond
sections 1 and 2 as a high risk area. The April 2013 leakage occurred in section
2 in the immediate vicinity of this separating barrier.

Following the leakages in the earlier years, the Company had proactively altered
the structure of new gypsum pond sections (3-6) such that a bentonite liner had
been placed beneath the HDPE membrane. The risk of an escalating fracture caused
by a seep leakage is therefore highly unlikely in these pond sections and a seep
as such does not constitute an environmental hazard.

The investigation also found that after the elevation of the gypsum pond in the
autumn of 2012, so called raffinate had been pumped into the pond from the
metals recovery plant. Raffinate is process solution from which valuable metals
have been precipitated and recovered, but which has not been purified at the
post-neutralization phase at the metals plant. The water quality in the gypsum
pond deteriorated as a result of this pumping arrangement. The water quality did
not have any impact on the occurrence of the November leakage, but to the extent
the leakage waters had to be discharged into the environment, raffinate may have
had a more acidifying impact on the environment than the waters otherwise stored
in the gypsum pond.

In addition to recommendations pertaining to water management, pond usage and
leakage risk management, VTT also gave recommendations on the long-term
development of the Company's safety culture. Certain project-phase legacies
remain in the Company's operational culture, due to which it is important for
the Company's Board and operative management to work together to clarify
management principles in order to align operational procedures with the
requirements of the ongoing production phase. VTT recommends sustained actions
to further improve the technical requirements of production and to continuously
assess and improve the safety culture. In addition, VTT recommends that the
Company further strengthens its internal resources, in particular as they
pertain to safety and environmental matters.

Measures taken by the Company on the basis of VTT's recommendations

The Company's Board and operative management have familiarized themselves with
VTT's report and recommendations. The Board is satisfied with VTT's
investigation, which diligently studied the reasons of the incident and provides
valuable input for the development of the Company's risk management and
organization.

Water management

Since the November 2012 leakage, a key area of development for the Company has
been the mitigation of risks related to water management and the achievement of
a sustainable water balance. In order to achieve these goals, Talvivaara has
established a separate organization focusing on water management, which is
responsible for the overall water balance management and the design and
implementation of necessary short-term and long-term water management measures.

Talvivaara commenced immediate actions following the November 2012 gypsum pond
leakage to reduce the water volume in all bioheapleaching safety ponds, gypsum
ponds and safety dams such that the safe treatment of spring melt waters could
be ensured and sufficient safety capacity in view of potential new leakages
could be created. As the gypsum pond section 2 had been identified as a high
risk area, but it was not possible to empty the pond section into other ponds in
the mining area due to the prevailing water balance situation, immediate
measures were in particular aimed at ensuring sufficient volume in safety dams
for the water contained in this pond section. This approach was successful, and
all waters from the 7 April 2013 leakage in section 2 were contained in the
safety dams located in the Southern part of the mining area. The leakage waters
will be purified and discharged into the environment within the schedule allowed
by discharge quotas and neutralization capacity.

Water purification capacity has during the early part of 2013 been increased
materially above the 1.3 Mm(3) annual discharge quota allowed by Talvivaara's
environmental permit. Further purification capacity will be constructed such
that by the end of 2013 the total treatment capacity exceeds 6 Mm(3) per annum.
This capacity is expected to be sufficient for water purification requirements
even during intense flooding and other exceptional circumstances.

At present Talvivaara is purifying and discharging into the environment excess
waters stored in the mining area within the 1.8 Mm(3) additional discharge quota
granted in February 2013 by the Kainuu Centre for Economic Development,
Transport and the Environment. However, the Company considers this discharge
quota insufficient for lowering risks related to water balance management to an
acceptable level, and therefore the Company has applied to the Northern Finland
Regional State Administrative Agency ("AVI") for an increase of the additional
discharge quota. In its report, VTT also states that attaining a safe
operational level requires a material increase in the quota for discharging
waters.

In addition to the temporary discharge quotas, the Company has applied to AVI
for a permanent removal of the annual water discharge quota from the Company's
environmental permit in order to sustainably manage the overall water balance.
No changes have been applied for the discharge limits of environmentally harmful
substances, and therefore no additional environmental burden is expected.

Talvivaara is currently preparing a holistic long-term water management plan,
which is expected to be completed by the end of June 2013. Central elements of
the plan comprise a nearly closed process water circuit, and separation and
separate treatment of natural run-off waters and waters accumulating in the open
pit. The technical prerequisites for a closed process water circuit are already
largely in place due to investments in reverse osmosis technology and other
process alterations. Significant progress has also been made in water separation
in early 2013, and the water catchment area at the mine has been materially
reduced as a result of new dam structures. These structures largely prevent run-
off waters from mixing with metal-containing waters.

Pond usage

The gypsum ponds are to be returned to their original planned usage as soon
possible, such that the excess water volume in the ponds is low at all times and
water quality is monitored on an ongoing basis. Bioheapleaching safety ponds
should also normally be empty. Both targets require the purification and
discharge of excess waters from the mine site in the near term and maintenance
of a sustainable water balance in the long term.


Safety culture

In the future Talvivaara will pay increasing attention on risk management and
active development of the Company's safety culture with the help of its internal
organization and, as required, external consultants. In order to ensure this
development the Company's sustainability organization will be strengthened by
1-3 people during the current year and a person responsible for safety will be
nominated for each production department. Required safety training will be
arranged for all levels of the organization in order to permanently establish
best industry practices as part of Talvivaara's day-to-day operations.

The Company's Board further states that the purpose of this announcement is to
publish the central observations and recommendations of VTT's investigation and
the measures taken by the Company on the basis of VTT's recommendations. There
are ongoing investigations by the police and the Safety Investigation Authority
relating to the gypsum pond leakage that include questions relating to
environmental permitting mechanics and judicial processes. The Company's Board
does not comment on such questions at this stage.



Enquiries
Talvivaara Mining Company Plc Tel +358 20 7129 800
Tapani Järvinen, Chairman of the Board of Directors
Kirsi Sormunen, Member of the Board of Directors


Talvivaara Mining Company Plc
Talvivaara Mining Company is an internationally significant base metals producer
with its primary focus on nickel and zinc using a technology known as
bioheapleaching to extract metals out of ore. Bioheapleaching makes extraction
of metals from low grade ore economically viable. The Talvivaara deposits
comprise one of the largest known sulphide nickel resources in Europe. The ore
body is estimated to support anticipated production for several decades.
Talvivaara has secured a 10-year off-take agreement for 100 per cent of its main
output of nickel and cobalt to Norilsk Nickel and entered into a long-term zinc
streaming agreement with Nyrstar NV. Talvivaara is listed on the London Stock
Exchange Main Market and NASDAQ OMX Helsinki. Further information can be found
at www.talvivaara.com.

Talvivaara implementing projects as a result of VTT investigation:
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Source: Talvivaaran Kaivososakeyhtiö Oyj via Thomson Reuters ONE
[HUG#1697340]




Unternehmen: Talvivaaran Kaivososakeyhtiö Oyj - ISIN: FI0009014716