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ATM Atacama Pacific Gold Corporation

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Share Name Share Symbol Market Type
Atacama Pacific Gold Corporation TSXV:ATM TSX Venture Common Stock
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Atacama Pacific Announces Continued Positive Metallurgical Results from Cerro Maricunga Oxide Gold Project

09/05/2013 9:00pm

Marketwired Canada


Editors Note: There is a photo associated with this press release. 

Atacama Pacific Gold Corporation (TSX VENTURE:ATM) ("Atacama Pacific") is
pleased to report that column percolation leach tests from the Cerro Maricunga
Oxide Gold Project continue to achieve consistent positive gold recoveries. The
test work was completed on gold mineralization taken from across the Cerro
Maricunga deposit with the goal of determining the impact of gold grade,
agglomeration and crush size (25, 50 and 150 mm) on gold recoveries. Table 1
summarizes the results of the completed metallurgical tests. Unless otherwise
noted, all crush sizes reference 100% passing (P100) through a screen of the
noted crush size. Highlights from the current test work include:




--  Average gold recoveries of 81.5% for non-agglomerated, 25 mm crushed
    mineralization 
--  Majority of leachable gold extracted in the first twenty days at a 25 mm
    crush 
--  Gold recoveries of 78% and 80% at a 50 mm crush 
--  No significant variation in gold recoveries between the three main zones
--  No significant difference in recoveries between average grade and low
    grade mineralization

Table 1 - Summary of Column Percolation Leach Test Results                  
----------------------------------------------------------------------------
                                    Gold                                    
Test                  Head Grad Recovery  Crush Size   NaCN                 
#     Zone             (g/t Au)      (%) (P100 = mm) (kg/t)             Note
----------------------------------------------------------------------------
60071 Crux Zone            0.48       80          25   0.75                 
------                ------------------------------------------------------
60074                      0.24       80          25   0.62                 
----------------------------------------------------------------------------
60077 Lynx Zone            0.49       82          25   0.75                 
------                ------------------------------------------------------
60080                      0.24       80          25   0.82                 
----------------------------------------------------------------------------
60083 Phoenix Zone         0.45       80          25   0.96                 
------                ------------------------------------------------------
60086                      0.24       82          25   0.85                 
----------------------------------------------------------------------------
65814 Composite of 3                                                        
       zones; 1 :1 :1                                                       
       ratio               0.49       85          25   0.78 Non-agglomerated
------                ------------------------------------------------------
65817                      0.45       80          25   0.37     Agglomerated
----------------------------------------------------------------------------
65828 Phoenix -                                                             
       Surface trench      0.53       84          25   1.05 Non-agglomerated
------                ------------------------------------------------------
65831                      0.53       82          25   0.48     Agglomerated
----------------------------------------------------------------------------
65822 Phoenix -                                                             
       Surface trench      0.50       80          50   0.91 Non-agglomerated
------                ------------------------------------------------------
65825                      0.50       78          50   0.40     Agglomerated
----------------------------------------------------------------------------
65842 Composite of 3                                                        
       zones               0.35       85        9(i)   0.72             HPGR
----------------------------------------------------------------------------
Notes: Gold recoveries based upon activated carbon assays; column tests run 
 for 98 to 127 days; non-agglomerated columns were prepared with approx. 5  
 kg/t of lime and agglomerated columns were prepared using approx. 12.5 kg/t
 cement. (i) crushed to P80 = 9 mm                                          



Gold recoveries from non-agglomerated mineralization crushed to 25 mm
(approximately P80 = 19 mm) ranged from 80% to 85%, averaging 81.5%, slightly
higher than the average gold recovery of 79.5% used in the Cerro Maricunga
Preliminary Economic Assessment ("PEA") press released on January 28, 2013. The
PEA envisioned a 3 stage crushing system to achieve a P80 = 19 mm crush. Leach
kinetics, time versus cumulative gold recoveries, were fast (see figure 1) with
the majority of the recoverable gold extracted within the first twenty days. 


To view the figure associated with this press release, please visit the
following link: http://media3.marketwire.com/docs/Test_Leach.jpg. 


Agglomeration Comparison Column Tests 

Three pairs of column tests (six columns) were undertaken to determine the
impact of agglomeration on gold recoveries. Each test pair, performed on subsets
of the same sample material, consisted of one non-agglomerated column and one
column using 12.5 kg/t of cement to agglomerate the crushed mineralization. The
tests confirmed that gold recoveries from Cerro Maricunga mineralization do not
benefit from agglomeration with those tests consistently attaining lower
recoveries in comparison to the non-agglomerated columns. The lower recoveries
are likely due to reduced permeability caused by agglomeration.


50 mm Crush Column Tests 

Two column tests were completed on mineralization crushed to 50 mm. Gold
recoveries of 80% for the non-agglomerated test and 78% for the agglomerated
test were achieved. The results are similar to the 78% gold recovery achieved in
an earlier column tests on 50 mm crushed material (see January 10, 2012 press
release) and only slightly lower than the recoveries attained from the 25 mm
crush columns.


150 mm Crush Column Tests 

Two column tests are underway on Cerro Maricunga gold mineralization crushed to
150 mm. After 80 days, gold recoveries are around 60% and are continuing to
rise. Previously, the coarsest crushed mineralization tested was P80 = 100 mm
which realized gold recoveries of 77%. Crushing to 150 mm may eliminate the
requirement for secondary and tertiary crushing circuits, however, the potential
benefit of reduced capital costs associated with eliminating the two crushing
circuits must be weighed against the lower gold recoveries obtained from
leaching coarse material. As the initial sample was composed of only +150 mm
material with no natural fines, a portion of the sample was crushed and finer
(-150 mm) crushed material was added to the column to achieve a P80 = 130 mm.


HPGR Column Test

One column test was completed on mineralization crushed with high pressure
grinding rolls ("HPGR") to P80 = 9 mm. Gold recoveries of 85% were attained with
recoveries of over 80% within the first 10 days. The HPGR option is being
reviewed as it may represent a lower cost option for the tertiary crushing
circuit considered in the PEA.


Metallurgical Test Details 

The column tests, conducted by Kappes, Cassidy and Associates, Reno, Nevada,
were run for 98 to 127 days which included a two week rest period followed by a
further four days of leaching. The 25 mm crush size columns were conducted on 50
kg of mineralized material placed in a 150 mm diameter column. The 50 mm crushed
material was undertaken on 200 kg of sample material placed in 240 mm columns.
The 150 mm sample charges weigh 700 kg and are still undergoing leaching in 440
mm columns.


The column tests were not optimized to minimize sodium cyanide ("NaCN")
consumption; however, NaCN consumption was low to moderate. The initial leach
solution for each column contained 1.0 g NaCN/l of solution and during the test,
the continued solution strength was maintained at a target level of 0.5 g
NaCN/l. NaCN consumption is projected to be low, in the order of 0.25 kg/t.


The tests were not optimized to minimize the amount of lime or cement necessary
to control solution alkalinity. Approximately 5 kg of lime was added to the
non-agglomerated samples to maintain at a pH level of 9 to 11. No additional
lime or cement was required during the testing. 


Column test extraction results were based upon granular activated carbon assays
vs. the calculated head grade (carbon assays plus tail assays).


About Atacama Pacific Gold Corporation

Atacama Pacific's primary mineral property is the Cerro Maricunga
oxide-associated, breccia-hosted gold project, located in Region III, 140
kilometres by road northeast of the city of Copiapo. In Atacama Pacific's
January 2013 PEA envisions a large open pit operation mining 80,000 tonne per
day with a conventional heap leach processing facility producing 2.7 million
ounces of gold over a 10 year mine life with cash costs of $652 per ounce. The
Cerro Maricunga property hosts a pit confined resource estimate of 2.46 million
ounces of gold (185.8 million tonnes grading 0.41 g/t gold) in the measured and
indicated category with a further 0.94 million ounces (75.4 million tonnes
grading 0.39 g/t gold) in the inferred category. The resource estimate is based
upon a cut-off grade varying from 0.15 to 0.18 g/t gold.


National Instrument 43-101 

Michael Easdon, a professional geologist registered with the American Institute
of Professional Geologists, is the independent qualified person for the current
exploration program and has reviewed, approved and verified the content of this
press release. Carlos Guzman, a mining engineer, Fellow of the Australasian
Institute of Mining and Metallurgy and a registered member of the Chilean Mining
Commission, is the independent qualified person as defined by National
Instrument 43-101 for the Preliminary Economic Assessment for the Cerro
Maricunga project. Mr. Guzman is a Principal and Project Director with NCL
Ingeneiria y Construccion Ltda., Santiago, Chile. 


Visit Atacama Pacific's website at www.atacamapacific.com.

FORWARD-LOOKING STATEMENTS

This news release contains forward-looking statements, including predictions,
projections and forecasts. Forward-looking statements include, but are not
limited to statements with respect to the results of preliminary economic
assessment, statements regarding the expectation and projections of gold
recoveries, statements regarding expectations for receipt of permits and
environmental approvals, exploration results (including with respect to water
resources), the success of exploration activities generally, mine development
prospects, and potential future gold production. Often, but not always,
forward-looking statements can be identified by the use of words such as
"plans", "planning", "expects" or "does not expect", "continues", "scheduled",
"estimates", "forecasts", "intends", "potential", "anticipates", "does not
anticipate", or "belief", or describes a "goal", or variation of such words and
phrases or state that certain actions, events or results "may", "could",
"would", "might" or "will" be taken, occur or be achieved. 


Forward-looking statements involve known and unknown risks, future events,
conditions, uncertainties and other factors which may cause the actual results,
performance or achievements to be materially different from any future results,
prediction, projection, forecast, performance or achievements expressed or
implied by the forward-looking statements. Such factors include, among others,
the results of due diligence activities, changes in economic parameters and
assumptions, the interpretation and actual results of current exploration
activities; changes in project parameters as plans continue to be refined; the
results of regulatory and permitting processes; future prices of gold; possible
variations in grade or recovery rates; failure of equipment or processes to
operate as anticipated; labour disputes and other risks of the mining industry;
the results of further economic and technical studies, delays in obtaining
governmental approvals or financing or in the completion of exploration, as well
as those factors disclosed in Atacama Pacific's publicly filed documents.


Although Atacama Pacific has attempted to identify important factors that could
cause actual actions, events or results to differ materially from those
described in forward-looking statements, there may be other factors that cause
actions, events or results not to be as anticipated, estimated or intended.
There can be no assurance that forward-looking statements will prove to be
accurate, as actual results and future events could differ materially from those
anticipated in such statements. Accordingly, readers should not place undue
reliance on forward-looking statements.


FOR FURTHER INFORMATION PLEASE CONTACT: 
Atacama Pacific Gold Corporation
Carl B. Hansen
President and CEO
416 861 8267
info@atacamapacific.com
www.atacamapacific.com

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