RIO Rio2 Limited New

Rio Alto Mining Limited ("Rio Alto" or the "Company") (TSX
VENTURE:RIO)(OTCQX:RIOAF)(BVLAC:RIO)(DBFrankfurt:MS2) is pleased to provide a La
Arena Project update and report assay results from 16 drill holes at the newly
discovered San Andres oxide gold target located adjacent to the recently
completed leach pad at the La Arena Gold Oxide Mine ("Oxide Mine") located in
Peru.


Development work at the Oxide Mine is complete and construction of the process
plant and camp facilities is being finished. To-date a 14 hectare leach pad and
a 57,500 cubic meter pregnant leach solution pond are finished. Commissioning of
the adsorption/desorption and electro winning plant will begin this month in
preparation for gold production. A 300 man camp, offices and associated
infrastructure will be completed in April.


The San Andres zone was identified as part of the Company's recently initiated
12,000m reverse circulation drilling program focused on expanding oxide gold
mineralization in and around the current La Arena gold oxide resource. San
Andres is a gold oxide, brecciated sandstone zone of mineralization located
along strike and to the north of the La Arena gold oxide resource. As the San
Andres zone is constrained by its location between the pad and the PLS pond, Rio
Alto will not drill this zone to define a resource, but will deliver mineralized
material from San Andres to the leach pad after evaluating blast hole sample
results and as permitted by the mine plan.


Significant intercepts from these drill holes are highlighted below. An economic
cut-off grade of 0.11 g/t in gold oxides was established by independent
engineers, Coffey Mining Pty Ltd, in the NI 43-101 study dated July 31, 2010.




--  58m @ 0.5g/t Au, 4.4g/t Ag in hole SA-R11-006 
--  42m @ 1.08g/t Au, 0.4g/t Ag in hole SA-R11-013 
--  60m @ 0.4g/t Au, 0.52g/t Ag including 28m @ 0.62g/t Au, 0.46g/t Ag in
    hole SA-R11-015 



Alex Black, President and COO of Rio Alto, commented, "We are pleased with this
first phase drilling success at La Arena, which supports our belief in the
excellent potential to expand the mineral resources on the property. The
drilling has identified mineralization beyond the current resources and
reserves. The 12,000 metre reverse circulation gold oxide exploration program
for 2011 is in progress and we expect future results will continue to
demonstrate the growth potential of this project."


Summary of Results

The San Andres zone is situated to the north east of the Ethel breccia. Two
layers of highly oxidized breccia sandstone outcrop at surface in the area.
Geologically, gold mineralization is associated within highly fractured and
oxidized sandstone rocks similar to La Arena's Calaorco and Ethel gold oxide
deposits. The sandstone bedding at San Andres dips gently to the south east and
the mineralization is controlled by this feature. Two layers of mineralization,
one 40 metres thick and the other 100 m thick, have been identified. A recent
geochemical survey identified gold anomalism similar to the Calaorco and Ethel
resources located at La Arena. Based on the geological and geochemical results a
reverse circulation drilling program comprising 2811 metres within 16 holes was
completed. In total 11 holes encountered mineralization above the economic
cutoff.




Hole ID             From          To      Length      Au g/t      Ag g/t
SA 01                 24          32           8        0.30        0.38
SA 01                 60          66           6        0.27        0.20
SA 01                200         224          24        0.33        0.58
SA 02                  6          24          18        0.28        0.21
SA 02                 50          58           8        0.39        0.20
SA 02                140         144           4        0.28        0.70
SA 03                 22          54          32        0.23        0.22
SA 04                  0          44          44        0.37        0.28
SA 04                130         136           6        0.39        0.63
SA 05                  6          12           6        0.27        0.20
SA 05                 66         148          82        0.21        0.45
Including             66          78          12        0.35        0.25
SA 06                184         242          58        0.50        4.24
SA 09                  8          22          14        0.24        0.20
SA 10                 44          52           8        0.25        4.50
SA 11                 36          48          12        0.20        0.27
SA 11                 80          98          18        0.24        1.54
SA 13                  0           8           8        0.27        0.20
SA 13                 28          70          42        1.08        0.40
SA 13                180         250          70        0.29        0.92
SA 15                 26          86          60        0.40        0.52
Including             58          86          28        0.62        0.46



Quality Control and Assurance

Sampling of the reverse circulation drilling and sample preparation were
performed by Rio Alto personnel; and were carried out under strict protocols
recommended in the NI 43-101 Technical Report dated July 31, 2010 prepared by
Coffey Mining Pty Ltd. Samples were taken every 2m and split in half to yield
seven to ten kilogram samples. Drill sample recovery was generally in excess of
90%. Rio Alto has a rigorous QA/QC program to control the chain-of-custody of
samples and the insertion of blanks, duplicates, and certified reference
standards in each batch of samples. Samples were shipped to CIMM-Peru in Lima
where they were dried, crushed, pulverized, and assayed. All gold assays were
obtained by standard 50g fire assaying with AA finish. All silver assays
reported in the press release were obtained by Aqua-Regia dissolution followed
by ICP measurement. CIMM-Peru is an ISO 9001:2000 certified laboratory.


Enrique Garay, M Sc. P. Geo. (AIG Member), Vice President Geology of Rio Alto is
the Qualified Person responsible for the management of the exploration program
and disclosure of the drill results as defined by National Instrument 43-101.
Mr. Garay has reviewed and verified the technical and scientific information in
this news release.


This news release contains certain forward-looking information including
statements concerning the expected timing for completion of a gold recovery
plant and production of gold. All statements included herein, other than
statements of historical fact, are forward-looking information and such
information involves various risks and uncertainties. There can be no assurance
that such information will prove to be accurate, and actual results and future
events could differ materially from those anticipated in such information. A
description of assumptions used to develop such forward-looking information and
a description of risk factors that may cause actual results to differ materially
from forward-looking information can be found in Rio Alto's disclosure documents
on the SEDAR website at www.sedar.com. Rio Alto does not undertake to update any
forward-looking information except in accordance with applicable securities
laws.


To learn more about Rio Alto Mining Limited, please visit: www.rioaltomining.com
or Rio Alto's SEDAR profile at www.sedar.com. 


ON BEHALF OF THE BOARD OF RIO ALTO MINING LIMITED

Alex Black, President & COO

Rio2 (TSXV:RIO)
Historical Stock Chart
From Jun 2024 to Jul 2024

Rio2 (TSXV:RIO)
Historical Stock Chart
From Jul 2023 to Jul 2024