Orosur Mining Inc. Announces Third Quarter Results of Financial Year 2013

Orosur Mining Inc ("OMI′ or the "Company′) (TSX:
OMI) (AIM: OMI), the South American focused gold producer and explorer,
today announces its results for the third quarter ending 28February
2013.

Further to the announcement of 8 March, the Company reiterates that
production for the quarter was 18,401 ounces (making 47,822 ounces for
the three quarters ended 28February 2013) and Orosur remains
on track to achieve its forecast production target of 63,000 to 68,000
ounces for the full year. The Arenal Deeps ramp has been completed, with
ore production targeted for April when development for the initial
mining levels is complete.

On April, 9 the Company issued a progress report on its exploration at
the Anillo and Pantanillo projects in Chile.

Operating and Financial Summary

¹Results are based on IFRS and expressed in US
dollars

²Operating cash cost is total cost excluding
royalties and capital tax on production assets

³Before non-cash working capital movements

Ignacio Salazar, Interim Managing Director, commented:

'In this quarter, the Company has completed the ramp at Arenal Deeps,
production and costs have been brought in line with expectations, we
have identified high priority drill targets at Anillo to start drilling
in May and have been re-evaluating Quebrada Pantanillo as a high
sulfidation gold system to improve the economics of the project. All of
this is in line with our strategy to optimise returns to shareholders?.

Financial Performance

• 
  Cash flow from operations for the quarter was US$ 8.0 million and $US
  16.6 million for the year to date, compared to US$ 6.8 million and $US
  17.0 million for the corresponding quarter and year to date of the
  prior financial year
  
• 
  The Company′s cash balance at 28^th February 2013 of US$ 5.2
  million compared to $US 3.8 million at 30th November 2012 and $US 11.4
  million at 31 May 2012. This is in line with expectations. The Company
  has US$ 6.5 million of committed but unutilized lines of credit
  available and it is not planning to use them within the current plans
  of developments and gold price assumptions.
  

Production and Costs

• 
  Production for the quarter increased by 34.6 per cent year on year to
  18,401 ounces (Q3 2012: 13,668 ounces). 47,822 ounces were produced
  during the three quarters (3Qs 2012: 38,071 ounces), an increase of
  25.6 per cent.
  
• 
  Cash operating costs for the quarter were $US 999 per ounce compared
  to $US 1,104 during the corresponding quarter of the prior year. Year
  to date, costs are $ 1,093 per ounce compared to $ 1,020 in the prior
  year.
  
• 
  Production and cash costs have been improving and are in line with
  expectations this quarter despite having encountered some operational
  issues in the open pits which are not yet completely resolved:
  
  
  • 
    The grade of ore mined from the Crucera pit during the quarter
    improved due to a more appropriate mining approach and improved
    ore control practices. The reconciliation of ounces produced from
    open pits compared to reserve models showed both positive and
    negative variances to plan during the quarter. To reduce this
    variability an experienced geologist has been recruited to fill
    the vacant mine geology superintendent position. Increased focus
    is being put on in-pit mapping, geological modeling and additional
    infill drilling where necessary in order to improve
    reconciliations and provide increased certainty on reserves.
    
  • 
    Lower than planned availability of the large open pit fleet was
    experienced during the quarter. A number of initiatives have been
    taken to improve performance. The maintenance department has been
    restructured and commencement of the San Gregorio open pit
    expansion project delayed to allow time for major component
    changes to be completed. These initiatives have already started to
    show improvements. The Company also plans to purchase a new
    excavator for the large fleet in the first quarter of 2013/14 to
    improve productivity.
    

• 
  Development of the ramp at Arenal Deeps was completed during the
  quarter, with ore production targeted for April when level development
  for the initial mining levels is complete.
  
• 
  The production forecast for the full year remains on track to be in
  the range of 63,000 to 68,000 ounces. A stronger production from
  Arenal in the final quarter as development will transition from waste
  to ore and higher grade Arenal ore is the key to reach this target.
  

Exploration Chile

• 
  Anillo ? successful completion of CSAMT (Controlled Source
  Audio-frequency Magneto Telluric) survey, to pinpoint the location of
  sub-vertical silica-bearing structures which may host economic
  gold-silver mineralization. The Company will commence drill testing
  the highest priority targets in May, 2013.
  
• 
  Pantanillo - new geological mapping and sampling has confirmed the
  evidence of a high sulfidation gold system under a steam heated zone
  at Quebrada Pantanillo. Additional activities over the last 6 months
  have been focused on the evaluation of new, potentially higher grade,
  exploration targets that lie outside of the existing mineral resource.
  This potential high sulfidation gold system is located approximately 4
  kilometres East-Southeast of Pantanillo Norte where the Company has
  defined a maiden National Instrument 43-101 measured and indicated
  mineral resource of 47 million tonnes at 0.69 grams of gold per tonne
  for 1.05 Million ounces of gold. The Company is currently evaluating
  the next summer campaign including geophysics and drilling at the new
  areas is expected to start in November 2013.
  

Exploration Uruguay Brownfield

During the first half of 2012/13, 44 drill holes equal to 4,530 meters
were completed at the Mahoma project (approximately 400 kilometres from
the San Gregorio mine). This included 1,560 metres of diamond drilling
and 2,970 metres of reverse circulation drilling (of which 1,830 meters
were for pre-collars). Assay results received for the final 9 holes
during the quarter are shown in the table below.

An NI-43-101 compliant resource is planned to be announced over the next
two months with the final report expected to be lodged subsequently.
Following the completion of this resource estimate, the Company
anticipates the commencement of a mining feasibility study which assumes
ore being trucked to the San Gregorio operation for processing.

The table below shows only the holes which had mineralized intercepts.

* intercepts consider a cut-off grade of 2.0 g/t and may include up-to 2
meters of below the cut-off grade

At Sobresaliente (6 kilometers from the mine), 14 holes for 1,444 meters
of drilling were completed during the quarter with the objective of
expanding resources and reserves. Drilling confirmed the existence of
good grades and widths beneath the currently planned pit at
Sobresaliente north. Drilling intercepts are reported in the following
table.

The table below shows only the holes which had mineralized intercepts.

* intercepts consider a cut-off grade of 0.4 g/t and may include up-to 2
meters of below the cut-off grade

At Argentinita (29 kilometers from the mine), 11 holes for 2,087 meters
were drilled during the quarter to investigate the potential to expand
underground resources. The partial (not all intercepts tested) results
of 7 out of the 11 holes below show the potential for extensions to
mineralization, and follow-up drilling will be required to define
resources in these zones.

The table below shows only the holes which had mineralized intercepts.

* intercepts consider a cut-off grade of 1.0 g/t and may include up-to 2
meters of below the cut-off grade

Exploration Uruguay Greenfield

Nine projects are currently under review as part of the Company ?s
greenfield exploration program in Uruguay. Geological mapping, sampling
and shallow RAB drilling was carried out in areas with gold
mineralization in quartz veins within granitic rock and shear zones in
basement rocks, 732 rock and soil samples were sent to the lab and
evaluation of these projects is ongoing.

ENDS

Qualified Person's Statement

The information presented in this press release has been reviewed by
Walter Muehlebach, GM Exploration of OMI and is considered to be in
compliance with NI 43-101 reporting guidelines. Mr Muehlebach is a
graduate in Geology of the Universidad Católica del Norte (Chile) and a
member of the Chilean Comisión Calificadora de Competencias en Recursos
y Reservas Mineras, and has 23 years of experience in the field of
mineral exploration.

About Orosur Mining Inc.

Orosur Mining Inc. is a fully integrated gold producer and exploration
company focused on identifying and developing gold projects in Latin
America. The Company operates the only producing gold mine in Uruguay
(San Gregorio), and has assembled an exploration portfolio of high
quality assets in Uruguay and Chile. The Company is quoted in Canada (OMI.TO)
and London (OMI).

Forward Looking Statements

All statements, other than statements of historical fact, contained or
incorporated by reference in this news release, including any
information as to the future financial or operating performance of the
Company, constitute 'forward-looking statements' within the meaning of
certain securities laws, including the 'safe harbour' provisions of the
Securities Act (Ontario) and the United States Private Securities
Litigation Reform Act of 1995 and are based on expectations estimates
and projections as of the date of this news release. There can be no
assurance that such statements will prove to be accurate, such
statements are subject to significant risks and uncertainties, and
actual results and future events could differ materially from those
anticipated in such statements. Forward-looking statements include,
without limitation success of exploration activities; permitting time
lines; the failure of plant; equipment or processes to operate as
anticipated; accidents; labour disputes; requirements for additional
capital title disputes or claims and limitations on insurance coverage.
The Company disclaims any intention or obligation to update or revise
any forward looking statements whether as a result of new information,
future events and such forward-looking statements, except to the extent
required by applicable law.

For further information, please contact:

Orosur Mining Inc

Ignacio
Salazar, Interim Managing Director, + 562 9246800

ignacio.salazar@orosur.ca

Tony
Shearer, Chairman

tony@tonyshearer.com

or

Canaccord
Genuity Limited (Nominated Adviser & Broker)

Andrew
Chubb/Ross Allister, +44 (0) 20 7523 8000