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Last updated on April 18, 2014 at 1:21 EDT

Positive results from preliminary metallurigical testwork on the Araguaia Nickel Project, Brazil

March 6, 2012

TORONTO, March 6, 2012 /PRNewswire/ – Horizonte Minerals plc, (TSX:HZM, AIM:HZM) (‘Horizonte’ or ‘the
Company’)
the exploration and development company focused in Brazil, is pleased to announce positive results from the preliminary
metallurgical testwork, from both pyrometallurgical and
hydrometallurgical testing, for its flagship 100% owned Araguaia Nickel
Project (‘Araguaia’) located south of the Carajás Mineral District of
Northern Brazil.

Highlights:

Pyrometallurgy

        --  Commercial grade of ferronickel produced in laboratory smelting
            tests on two ore blends (35.3% nickel to 40.5% nickel)
        --  High nickel recoveries in laboratory tests (94.4% to 96.1%)

Hydrometallurgy

        --  Atmospheric tank leach ('ATL') tests achieved up to 89% nickel
            extraction and up to 93% cobalt extraction in 4 hours on ore
            blend samples
        --  Acid consumption for the ATL laboratory tests ranged from 506 -
            752 kg/tonne
        --  Bottle roll leach ('BRL') tests achieved up to 89% nickel
            extraction and 92% cobalt extraction on ore blend samples
        --  Acid consumption for the BRL laboratory tests on ore blend
            samples ranged from 651 - 729 kg/tonne

Horizonte CEO Jeremy Martin said, The completion of the initial phase of metallurgical test work is a
significant milestone at Araguaia with both process routes returning
positive results, which is an excellent outcome.  The mineral resources
on the project are saprolite and transition dominated, which combined
with the good infrastructure and low cost hydroelectric power in the
district made the tried and tested pyrometallurgical route a key
process option.  Today in Brazil there are 4 plants producing
ferronickel via the pryometallurgical route, the most recent of these
is Anglo American’s Barro Alto project that started nickel production
in March 2011.  The results returned from our initial pyrometallurgical
tests showed that it is possible to produce ferronickel with grades
ranging from 35.3% nickel to 40.5% nickel with good overall recovery
rates.  A ferronickel product within this grade range can be sold
directly to stainless steel producers.

“In parallel hydrometallurgical test work was undertaken focused on
Atmospheric Tank Leach (ATL) and Bottle Roll Leach (BRL) as a precursor
test for atmospheric heap leaching.  Sulphuric acid was used on both
types of leaching tests. The results from the ATL tests were positive
showing that there are high nickel recoveries up to 89% with moderate
acid consumption and the BRL tests also indicated good nickel
recoveries.

“The completion of the preliminary metallurgical testwork is a major
step in de-risking the project, we are now able to demonstrate two
process routes that with additional testing are potentially suitable
for commercial production.  Shortly we will be awarding the contract
for the Phase 2 pyrometallurgical test work to run a pilot plant of
approximately 100 tonnes of ore on a continuous feed basis.  I look
forward to updating shareholders as we advance this work.”

Further Details

Pyrometallurgy

The pyrometallurgical test programme was undertaken at the laboratories
of Xstrata Process Support (‘XPS’) in Sudbury, Ontario, Canada.

This test programme examined the pyrometallurgical smelting performance
of laterite ore from the Araguaia Nickel Project. For the programme,
samples of the limonite, transition and saprolite zones were submitted
to XPS. The results of chemical analysis on the samples of these
materials dried at 105(0)C showed the following results:

Chemical assays on ore materials sent to XPS

     ____________________________________________
    |Sample    |Ni  |Co   |Fe  |SiO2 |MgO  |Al2O3|
    |__________|____|_____|____|_____|_____|_____|
    |Limonite  |1.23|.21  |37.9|18.10|2.70 |8.3  |
    |__________|____|_____|____|_____|_____|_____|
    |Transition|1.76|0.064|18.8|42.78|9.73 |5.25 |
    |__________|____|_____|____|_____|_____|_____|
    |Saprolite |1.61|0.04 |10.3|42.14|18.41|8.13 |
    |__________|____|_____|____|_____|_____|_____|

The following blends, considered representative of the combined
Pequizeiro and Baião deposits at a 1% nickel cut-off, were made up at
XPS. Blend 1 is representative of the entire blended ore zones, while
Blend 2 represents the blend of the transition and saprolite zones
only.

     _____________________________________
    |Blend  |            Proportion, %    |
    |       |_____________________________|
    |       |Limonite|Transition|Saprolite|
    |_______|________|__________|_________|
    |Blend 1|15      |45        |40       |
    |_______|________|__________|_________|
    |Blend 2|0       |53        |47       |
    |_______|________|__________|_________|

After calcining at 900(0)C, smelting tests were carried out at 1,520(0)C with varying amounts of reductant. It was found that ferronickel alloy
having grades between 21.9% Ni and 40.5 % Ni could be produced from the
transition and saprolite materials, with the Ni recovery ranging from
94.4% to 97.6%. Further, the tests showed that in the case of Blend 1,
a ferronickel product averaging 34.1% Ni could be produced at an
average Ni recovery of 95.1%, while in the case of Blend 2, ferronickel
grading 35.3% Ni could be produced, with a Ni recovery of 96.1%. 
Material grading 35% Ni is a sought after grade of ferronickel by
stainless steel producers.

Horizonte ores have a high SiO(2)/MgO ratio, in a similar range as that found at the BHP Billiton Cerro
Matoso ferronickel operation. The XPS study also developed a Metsim
model of a potential reduction/smelting process for the Araguaia ore
and found that the energy requirements for Horizonte will be similar to
published data for laterite smelting.

Hydrometallurgy

The preliminary hydrometallurgical testwork was undertaken at the
Wardell-Armstrong International (‘WAI’) test laboratories at Wheal
Jane, Cornwall, UK. Two separate approaches to hydrometallurgical
processing were tested, Atmospheric Tank Leaching and Bottle Roll Tests
aimed at a preliminary investigation for Heap Leaching. Sulphuric acid
was selected for both types of leaching tests.

Atmospheric Tank Leach Tests

Preliminary atmospheric tank leach tests were undertaken under different
test conditions to investigate the leachability of Araguaia blended ore
with respect to the effect of particle size, solid/liquid ratio, acid
strength, leaching temperature, leach time on metal recoveries and acid
consumptions. A composite feed ore blend consisting of 15% limonite,
45% transition and 40% saprolite core drill samples was used to carry
out the 21 batch tests.

The batch tests clearly established that Araguaia laterite ore was
leachable in tanks with promising results. Nickel leach rates were
encouraging with up to 65% of nickel extracted within the first hour
and 89% extraction achieved in 4 hours leaching. Ranges of 70-89%
recovery for nickel and 68-93% recovery for cobalt, with acid
consumptions of 500 – 750 kg/t, were achieved in 16 of the 21 tests.

The results of a selection of the tests based on assays of the solids
are tabulated below:

     _________________________________________________________________________
    |        | Ore |     |  Acid  |Leach|Leach|   Ni   |   Co   | Acid | Acid |
    |TEST ID |size | S/L |Strength|Temp.|Time |Recovery|Recovery|Cons. |Cons. |
    |        |(µm) |Ratio| (wt %) |(0C) |(hr) |  (%)   |  (%)   |(kg/t)|(kg/kg|
    |        |     |     |        |     |     |        |        |      | Ni)  |
    |________|_____|_____|________|_____|_____|________|________|______|______|
    |BaseTest| -75 | 1/3 |    80  |  80 |   4 |  80.8% |  87.3% |  644 |   51 |
    |1       |     |     |        |     |     |        |        |      |      |
    |________|_____|_____|________|_____|_____|________|________|______|______|
    |ATL1    |-1000| 1/3 |    80  |  80 |   4 |  79.4% |  82.5% |  658 |   54 |
    |________|_____|_____|________|_____|_____|________|________|______|______|
    |ATL2    |-500 | 1/3 |    80  |  80 |   4 |  81.3% |  85.4% |  640 |   51 |
    |________|_____|_____|________|_____|_____|________|________|______|______|
    |ATL3    |-150 | 1/3 |    80  |  80 |   4 |  83.3% |  86.7% |  667 |   51 |
    |________|_____|_____|________|_____|_____|________|________|______|______|
    |ATL 5   | -75 | 1/2 |    80  |  80 |   4 |  71.7% |  75.3% |  731 |   65 |
    |________|_____|_____|________|_____|_____|________|________|______|______|
    |ATL10   | -75 | 1/3 |    60  |  80 |   4 |  70.9% |  68.3% |  506 |   45 |
    |________|_____|_____|________|_____|_____|________|________|______|______|
    |ATL12   | -75 | 1/3 |   100  |  80 |   4 |  89.1% |  93.1% |  752 |   54 |
    |________|_____|_____|________|_____|_____|________|________|______|______|

Bottle Roll Leach Tests

Sixteen Bottle Roll tests were performed at WAI test laboratories using
separate limonite, transition and saprolite samples as well as a
composite ore blend. The tests were carried out under atmospheric
pressure and ambient temperature. Solid/liquid ratio was 1:10 using 150
grams of feed ore for each test. Two ore sizes: 6.35 and 3.35 mm and
two acid concentrations: 75 and 100 g/L were tested for each type of
ore.

At the end of 91 days leaching, the transition and saprolite samples
produced nickel recoveries in excess of 85% and the composite feed ore
blend generated nickel recoveries in the order of 85-90%. As was
expected, nickel recoveries for the pure limonite samples were lower
(51%). Acid consumptions varied in the range of 400-800 kg/t ore for
different ore types and test conditions.

Tabulated results for 10 of the tests based on solid analysis are given
below

     _____________________________________________________________________
    |       |               |Leach|   Ni   |   Co   |Acid Cons.|Acid Cons.|
    |Test ID|Description    |Days |Recovery|Recovery|  (kg/t)  |(kg/kg Ni)|
    |       |               |     |   %    |   %    |          |          |
    |_______|_______________|_____|________|________|__________|__________|
    |BRT 1  |Lim - 3.35 - 75|  91 |   49%  |   27%  |     403  |      68  |
    |       |gpL            |     |        |        |          |          |
    |_______|_______________|_____|________|________|__________|__________|
    |BRT 2  |Lim - 3.35 -   |  91 |   52%  |   27%  |     447  |      72  |
    |       |100 gpL        |     |        |        |          |          |
    |_______|_______________|_____|________|________|__________|__________|
    |BRT 5  |Sap - 3.35 - 75|  91 |   86%  |   89%  |     742  |      54  |
    |       |gpL            |     |        |        |          |          |
    |_______|_______________|_____|________|________|__________|__________|
    |BRT 6  |Sap - 3.35 -   |  91 |   87%  |   86%  |     878  |      64  |
    |       |100 gpL        |     |        |        |          |          |
    |_______|_______________|_____|________|________|__________|__________|
    |BRT 9  |Tra - 3.35 - 75|  91 |   81%  |   55%  |     640  |      48  |
    |       |gpL            |     |        |        |          |          |
    |_______|_______________|_____|________|________|__________|__________|
    |BRT 10 |Tra - 3.35 -   |  91 |   88%  |   64%  |     654  |      45  |
    |       |100 gpL        |     |        |        |          |          |
    |_______|_______________|_____|________|________|__________|__________|
    |BRT 13 |Blend - 3.35 - |  91 |   81%  |   83%  |     720  |      56  |
    |       |75 gpL         |     |        |        |          |          |
    |_______|_______________|_____|________|________|__________|__________|
    |BRT 14 |Blend - 3.35 - |  91 |   89%  |   92%  |     770  |      54  |
    |       |100 gpL        |     |        |        |          |          |
    |_______|_______________|_____|________|________|__________|__________|
    |BRT 15 |Blend - 6.35 - |  91 |   85%  |   87%  |     651  |      48  |
    |       |75 gpL         |     |        |        |          |          |
    |_______|_______________|_____|________|________|__________|__________|
    |BRT 16 |Blend - 6.35 - |  91 |   89%  |   89%  |     729  |      51  |
    |       |100 gpL        |     |        |        |          |          |
    |_______|_______________|_____|________|________|__________|__________|

Metallurgical testing of Horizonte’s laterite deposits continues, with a
planned test programme, about to commence shortly, aimed to test the
upgrading of the Ni level in ore samples using a variety of new,
advanced upgrading technologies.

Dr. Phillip Mackey P.Eng., Ph.D., FCIM, is the Qualified Person as
defined by NI 43-101 for the metallurgical testing programme on the
Araguaia Nickel Project. Dr. Mackey has reviewed and approved the
contents of this news release as it relates to the results of the
preliminary metallurgical testing programme.

About Horizonte Minerals:
Horizonte Minerals plc is an AIM and TSX listed exploration and
development Company with a portfolio of nickel and gold projects in the
Carajas District of Brazil.  The Company is focused on creating value
by generating and rapidly advancing exploration projects in tandem with
joint ventures with major mining companies, providing mid-term cash
flow, which is then used to develop the business and pipeline projects.

Horizonte has two committed major mining partners: Teck Resources
Limited, a major strategic shareholder in the Company, and AngloGold
Ashanti Limited, a JV partner on the gold portfolio.

Horizonte owns 100 per cent of the advanced Araguaia nickel project
located to the south of the Carajas mineral district of northern
Brazil.; the project has the potential to deliver a resource with size
and grades comparable to other world-class projects in northern Brazil.

In addition, Horizonte and AngloGold Ashanti have a US$5.3 million
exploration alliance to generate and develop new and existing gold
targets within two areas of Brazil and a further JV with the major
whereby AngloGold Ashanti can earn into 51% of the Falcao gold project
by expending US$4.5 million over three years with the right to earn a
further 19% by taking the project to Pre-feasibility Study.

Horizonte is well funded to accelerate the development of its core
projects.

CAUTIONARY STATEMENT REGARDING FORWARD LOOKING INFORMATION

Except for statements of historical fact relating to the Company,
certain information contained in this press release constitutes
“forward-looking information” under Canadian securities legislation.
Forward-looking information includes, but is not limited to, statements
with respect to the potential of the Company’s current or future
property mineral projects; the success of exploration and mining
activities; cost and timing of future exploration, production and
development; the estimation of mineral resources and reserves and the
ability of the Company to achieve its goals in respect of growing its
mineral resources; and the realization of mineral resource and reserve
estimates. Generally, forward-looking information can be identified by
the use of forward-looking terminology such as “plans”, “expects” or
“does not expect”, “is expected”, “budget”, “scheduled”, “estimates”,
“forecasts”, “intends”, “anticipates” or “does not anticipate”, or
“believes”, or variations of such words and phrases or statements that
certain actions, events or results “may”, “could”, “would”, “might” or
“will be taken”, “occur” or “be achieved”. Forward-looking information
is based on the reasonable assumptions, estimates, analysis and
opinions of management made in light of its experience and its
perception of trends, current conditions and expected developments, as
well as other factors that management believes to be relevant and
reasonable in the circumstances at the date that such statements are
made, and are inherently subject to known and unknown risks,
uncertainties and other factors that may cause the actual results,
level of activity, performance or achievements of the Company to be
materially different from those expressed or implied by such
forward-looking information, including but not limited to risks related
to: exploration and mining risks, competition from competitors with
greater capital; the Company’s lack of experience with respect to
development-stage mining operations; fluctuations in metal prices;
uninsured risks; environmental and other regulatory requirements;
exploration, mining and other licences; the Company’s future payment
obligations; potential disputes with respect to the Company’s title to,
and the area of, its mining concessions; the Company’s dependence on
its ability to obtain sufficient financing in the future; the Company’s
dependence on its relationships with third parties; the Company’s joint
ventures; the potential of currency fluctuations and political or
economic instability  in countries in which the Company operates;
currency exchange fluctuations; the Company’s ability to manage its
growth effectively; the trading market for the ordinary shares of the
Company; uncertainty with respect to the Company’s plans to continue to
develop its operations and new projects; the Company’s dependence on
key personnel; possible conflicts of interest of directors and officers
of the Company, and various risks associated with the legal and
regulatory framework within which the Company operates.

Although management of the Company has attempted to identify important
factors that could cause actual results to differ materially from those
contained in forward-looking information, there may be other factors
that cause results not to be as anticipated, estimated or intended.
There can be no assurance that such statements will prove to be
accurate, as actual results and future events could differ materially
from those anticipated in such statements.

SOURCE Horizonte Minerals plc


Source: PR Newswire