Mariana Resources Ltd

AIM and PLUS code: MARL

12 April 2011                          

Third Drill Campaign Completed, Las Calandrias Gold-Silver Project, Santa Cruz, Argentina

Mariana Resources Ltd ('Mariana' or 'the Company'), the AIM quoted exploration and development company focused in Argentina and Chile, announces that the third campaign at its 100% owned Las Calandrias Gold-Silver Project ('Las Calandrias') has been completed with further positive intersections at the Calandria Norte and Nido Norte prospects.  Las Calandrias is located in the prospective Deseado Massif gold-silver district in Southern Argentina.

Overview

�        Diamond drilling campaign which commenced in September 2010 comprised 212 infill and exploratory drill holes for 29,739m

�        Drilling has outlined a rhyolite-hosted bulk tonnage style gold-silver deposit at the Calandria Sur prospect which is open to the NW and SE

�        Second discovery with resource potential at the high grade La Calandria Vein hosted by the Calandria Norte rhyolite dome

�        Third centre of mineralisation discovered over a strike length of 850m along the Despreciada structure at the extensive Nido Norte rhyolite dome, west of the Calandria Norte prospect

�        Encouraging intersections from the latest batch of results include:

o       La Calandria

- 10m @ 4.0 g/t gold and 5 g/t silver including 0.5m @ 24 g/t Au & 26 g/t Ag from 99m;

- 0.3m @ 17.6 g/t Au, and 320 g/t Ag from 154m

o       Nido Norte

- 6.25m @ 1.2 g/t Au and 10 g/t Ag from 138.7m;

- 0.75m @ 8.0 g/t Au and 54 g/t Ag from 71.8m;

- 18.1m @ 1.5g/t Au and 15g/t Ag from 90.9m including 1.0m @ 11.2 g/t Au and 96 g/t Ag    from 102.1m

�        Maiden resource for Calandria Sur and now including La Calandria Vein at Calandria Norte, due May 2011

�        Targets for the next campaign (Q3 2011) likely to include La Calandria Vein extensions, Nido Norte trend, Calandria Norte dome margin, Nido Norte dome, Calandria Sur feeder zones and untested Induced Polarisation ('IP') anomalies

Commenting today, Chairman John Horsburgh said, "Encouraging scout drill results at Nido Norte confirm a prime target for deeper drilling over 850m strike below approximately 120m.  Additional intersections of high grade vein-breccia style at La Calandria Vein, hosted within the Calandria Norte rhyolite dome confirm potential to be included in the maiden resource estimation along with Calandria Sur."

Calandria Norte Prospect

Results were received for four holes which include two further high grade gold and silver intersections at La Calandria Vein:

�        Hole CND229 - 10m @ 4.0 g/t gold and 5 g/t silver including 0.5m @ 24 g/t Au, & 26 g/t Ag from 99m

�        Hole CND230 -  0.3m @ 17.6 g/t Au and 320 g/t Ag from 154m

Pending results from 11 drill holes include four La Calandria Vein intersections approximately 150-220m below surface and two follow-up vein-breccia intersections at La Morena Vein.

An updated gm-m gold longitudinal section (gm Au x metres, see figure) shows the concealed vein system extending over at least 450m strike.  It consists of NE trending high grade vein-breccias (up to 1.5m wide) dipping steeply NW and plunging shallowly SW within a stockwork zone up to 30m wide.  See summary of La Calandria intersections to date in Table 1 below.

Geological consultants Mine Development Associates ('MDA') of Reno, Nevada have indicated that an initial resource estimate will follow receipt of metallurgical input.

         Table 1: Summary of La Calandria Vein intersections

Nido Norte

Assay results from a further 26 exploratory drill holes along the 1.8km La Despreciada structure were received with dome-hosted vein-breccia and stockwork gold-silver mineralisation intersected in 13 holes, extending the target trend for deeper drilling to 750 to 850m long.  The target is mostly untested below a depth of 120m.

Follow-up hole NND 221 intersected chalcedonic breccias up to 3m wide and a sulphide stockwork halo 25m wide, with 18.1m @ 1.5g/t Au and 15g/t Ag from 90.9m.  Drill hole NND 221 was drilled 60m south of earlier hole NND162 which intersected 26.3m @ 1.0 g/t Au and 8 g/t Ag from 55m, incl. 1.6m @ 5.2 g/t Au & 71 g/t Ag from 64.5m.

Latest Nido Norte intersections included:

�     Hole NCD180 - 0.75m @ 8.0 g/t Au and 54 g/t Ag from 71.8m

�     Hole NCD220 - 6.25m @ 1.2 g/t Au and 10 g/t Ag from 138.7m

�     Hole NND221 - 18.1m @ 1.5 g/t Au and 15 g/t Ag from 90.9m, incl. 1m @ 11.2 g/t Au and 96 g/t Ag from 102.1m

Drill hole locations are shown on the drill plan and a summary of intersections is included in Table 2 at the end of this news release.

El Nido IP Targets

A total of 21 holes tested broad IP targets at Nido Sur and Gamekeeper prospects with no significant assays received.  Other El Nido IP targets to be tested in the next drill campaign include Nido Este, Loica and Pichones.

Calandria Sur Prospect

Results are pending for 12 holes drilled to test for possible NW and SE extensions of Calandria Sur mineralisation.

Resource estimation for the Calandria Sur prospect by MDA is nearing completion.  MDA requires input on cut-off grades to come from the preliminary metallurgical testwork being undertaken at Metcon Laboratories in Sydney, Australia, under the supervision of Consulting Metallurgist Peter Lewis.  See website for testwork outlined in the NI 43-101 technical report on Las Calandrias by MDA dated 24 November 2010.  Test results and report are expected mid-May 2011.  The initial resource estimation will now include La Calandria Vein at Calandria Norte and will follow receipt of metallurgical input.

Fourth Las Calandrias Drill Campaign

When outstanding assay results have been received and all results assessed, the next drilling is highly likely to focus on La Calandria and Morena Veins depth extensions, Calandria Norte dome margin breccias; Nido Norte depth extensions, Nido Norte root zones, Calandria Sur feeder zones, and IP targets at Pichones, Loica and Nido Este.

Las Calandrias Project Background

Las Calandrias comprises multiple zones of gold mineralisation hosted by rhyolite domes over a 10.5km² area..  In 2009, 16 scout holes (1,763m) tested the Calandria Norte vein- breccia and Calandria Sur dome breccia targets where significant gold mineralisation was discovered (see news release 28 October 2009).    The Q1/Q2 2010 drill programme consisted of 4,400m in 37 holes and tested Calandria Sur (28 holes/3,212m); Calandria Norte (2 holes/299m), El Nido Este (2 holes/309m) and El Nido Norte (5 holes/580m).  The Q3 2010 programme consisted of 14,004m in 110 holes; Calandria Sur (56 holes/6,186m); Calandria Norte (43 holes/6,175m); Nido Norte (7 holes/1,054m); Nido Oeste (2 holes/421m); La Herradura (2 holes/168m).

The third drill programme (September 2010 to April 2011) consisted of 29,739m in 212 holes and tested Calandria Sur (74 holes/8,933 m); Calandria Norte (64 holes/9,605 m), El Nido Norte (44 holes/7469m), Nido Sur (18 holes/ 1883 m), Nido Oeste (9 holes/1,550m) and other targets (3 holes/300 m).

Table 2: Selected Calandria Norte and El Nido Intersections

Intervals are weighted averages with 3m maximum < 0.2 g/t Au within the intervals.

ADDITIONAL INFORMATION

Drilling has been undertaken by ECOMINERA. The drill programme was directed by the Argentina Exploration Manager, Dr Gustavo Rodriguez under supervision of Executive Chairman Mr John Horsburgh.. Exploration information in this announcement has been compiled by John Horsburgh who is a Fellow of the Australasian Institute of Mining and Metallurgy.  Mr Horsburgh has sufficient experience relevant to the style of mineralization and types of gold deposit under consideration and to the activity that he is undertaking to qualify as a Competent Person as defined in the JORC Code.

Quality Assurance/Quality Control

All technical information for the Company's Argentina projects is obtained and reported under a quality assurance and quality control (QA/QC) program. All samples are collected under the supervision of the Company geologists and dispatched via commercial transport to ALS Chemex laboratories in Mendoza, Argentina, and assayed in Santiago de Chile. ALS Chemex's quality system complies with the requirements for the International Standards ISO 9001:2000 and ISO 17025: 1999. Samples returning greater than 10 g/t gold and/or greater than 100 g/t silver are assayed using gravimetric analyses.  Systematic assaying of sample duplicates and commercially prepared standards and blanks is performed for analytical reliability.

**ENDS**

For further information please visit website at www.marianaresources.com or contact the following.

About Mariana Resources

Mariana Resources Ltd is an AIM quoted exploration and development company with an extensive portfolio of gold, silver and copper projects in Argentina and Chile.  In Southern Argentina, in addition to the Las Calandrias gold-silver discovery, the Company has the Sierra Blanca silver-gold prospect (70%); the Los Amigos joint venture (49%) with Hochschild Mining and a 160,000 Ha land package (100%).  All of these projects are located in the Deseado Massif epithermal gold-silver district in mining-friendly Santa Cruz province of southern Argentina, which hosts four mines and several advanced projects.

In Chile, Mariana has a joint venture with US based international mining and natural resources company Cliffs Natural Resources Inc., to explore for Iron Oxide-Copper-Gold deposits ('IOCG') in a 92,000 km� area ('SCM Mariana Area') in north-central Chile along the highly prospective Atacama Fault Zone.  The SCM Mariana Area includes the 44km� Buenaventura and 46km� Perro Chico IOCG projects.  Mariana is also evaluating a number of gold-silver and copper-gold opportunities away from the Cliffs JV area, as part of a new initiative.

Felicity Edwards

St Brides Media and Finance Ltd

Chaucer House

38 Bow Lane

London

EC4M 9AY

Tel: +44 (0) 207 236 1177

Mob: +44 (0) 7748 843871

Fax: +44 (0) 207 236 1188

Email: felicity@sbmf.co.uk

Web: www.stbridesmedia.co.uk