Andean American Gold Corp.

Andean American Gold Corp.

October 09, 2008 09:05 ET

Andean American Mining Receives Excellent Metallurgy Report From Knelson Gravity Solutions for the Invicta Project

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Oct. 9, 2008) - Andean American Mining Corp. (TSX VENTURE:AAG)(FRANKFURT:AQN)(BVL:AAG) has received the final report from Knelson Gravity Solutions concerning the recovery of high grade gold and polymetallic ore from the Invicta Project, Peru. The primary purpose of the testing was to determine gravity recovery using Knelson continuous variable discharge (CVD) technology.

The results of the testing of the 650 kilogram sample are fully expressed in the 98 page technical report authored by Peacocke & Simpson, minerals processing engineers and representatives for Knelson Gravity Solutions. All assays were conducted by SGS Lakefield (PTY) Ltd. of Randfontein RSA, a SANAS(i) Certified Laboratory.

These results allow the Invicta project to now finalize the flowsheet and minimize the flotation system while improving overall recoveries in lowering operating costs.

In the Executive Summary, Knelson Gravity Solutions reports the following:

- CVD amenability testing of the sample using a Knelson MD3 low-yield cone in multi-pass mode indicated that grinding to nominal 500um was adequate to achieve good gravity recovery of gold, silver and lead, but that further grinding to 250um was required to enhance recovery of copper and zinc.

- Bulk CVD testing was thus undertaken using a 500um grind for the rougher concentration stage, followed by grinding to 250um prior to CVD scavenger concentration.

- CVD concentration in this flowsheet yielded recoveries of 88% Au, 81% Ag, 61% Cu, 63% Zn and 84% Pb to 37% mass yield, to a concentrate assaying 14.3 g/t Au, 147 g/t Ag, 2.4% Cu, 3.2% Zn and 3.1% Pb.

- Cleaner concentration of CVD concentrate via various methods indicated final recoveries to cleaner concentrate of +/-50-60% Au, 30-40% Ag, +/-75% Pb and +/-25% Cu & Zn to 10% mass yield. Concentrate grades were of the order of 40g/t Au, greater than 200 g/t Ag, 11% Pb, 2.7% Cu and 3.4% Zn. Beyond this mass pull (i.e. greater than 10% mass) gravity recovery of all metals was essentially proportional to mass yield (i.e. unit slope).

- It seems therefore that scavenger flotation may be required subsequent to CVD processing in order to maximise recovery; testing of this flowsheet yielded overall recoveries in excess of 94% for all metals. Overall mass yield was +/-47% (37% via CVD gravity, 10% via flotation). Flotation was rapid and froth was barren within 7 minutes. Regrinding beyond the grind suitable for CVD (250um) was not beneficial to flotation performance.

- Leach tests were undertaken on most products and by-products, and a summary of overall gold recovery via various permutations of flowsheet is shown below.

Also shown below is a table of base metal recoveries and grades at increasing gravity mass yield and with addition of floatation to gravity tails.

(i)SANAS, the South African National Accreditation System, is recognized by the South African Government as the single national accreditation body that gives formal recognition that Laboratories, Certification Bodies, Proficiency Testing Scheme Providers and Good Laboratory Practice (GLP) test facilities are competent to carry out specific tasks.

Table i: Gold Recovery via various process options

Au Recovery NaCN
Process (%) (kg/t)
Whole ore leach, 24hrs, 1kg/t NaCN 46.5 2.1
Whole ore leach, 72 hrs, 3kg/t NaCN 83.5 5.7
CVD concentration 87.6 N/A
CVD concentration, flotation of CVD tails(1) 96.9 N/A
CVD concentration, regrind and flotation of CVD tails(1) 97.8 N/A
CVD concentrate leach, 24 hrs, 1kg/t NaCN 47.6 0.7
CVD concentrate leach, 72 hrs, 3kg/t NaCN 74.6 1.3
CVD concentrate leach, regrind, 24 hrs, 1kg/t NaCN 43.5 0.8
CVD/flotation concentrate leach, 24 hrs, 1kg/t NaCN(2) 52.6 0.9
CVD/flotation concentrate leach, 72 hrs, 3kg/t NaCN(2) 82.5 1.6
CVD tails leach, 24 hrs, 1kg/t NaCN 7.9 0.7
CVD/flotation tails leach, 24 hrs, 1kg/t NaCN 2.0 0.4
CVD/regrind - flotation tails leach, 24 hrs, 1kg/t NaCN 1.0 0.5

Note 1: Recoveries shown here are those of CVD concentrate and cleaned
flotation concentrate. Flotation cleaner tails is assumed to report to
process tails. Mass yield for proportionate NaCN consumption calculation is
taken as CVD concentrate and cleaned flotation concentrate.

Note 2: It is assumed here that cleaned flotation concentrate would perform
similarly to CVD concentrate when leached.

Note: Overall recovery and sodium cyanide consumption for any chosen
process route can be calculated by summing the individual stage recoveries,
e.g. the recovery via CVD, flotation of CVD tail, equals 72-hour leach of
combined CVD and flotation concentrates and leach of floatation tails would
be 84.5% (82.5%+2.0%) for NaCN consumption of 2.0kg/t.

Table ii: Base metal recoveries and grades via various process options

Process Copper (%) Zinc (%) Lead (%)
Rec'y Grade Rec'y Grade Rec'y Grade
CVD Ro/Sc/CI to 10% mass +/-18 +/-2.7 +/-18 +/-3.4 +/-75 +/-11
CVD Ro/Sc/CI to 20% mass +/-35 +/-3.0 +/-3.0 +/-3.5 +/-80 +/-6
CVD Ro/Sc to 37% mass 63 2.5 62 3.0 84 3.0
CVD Ro/Sc, float tails 44% mass 98 3.1 98 4.2 94 2.9
CVD Ro/Sc, float tails 47% mass 98 3.0 98 4.0 94 2.8

Note: Recoveries and grades at 10 and 20% mass yield have been interpolated
from charts. Note that copper and zinc grades from gravity processing
increase with mass yield as lead is depleted (thus no longer displacing Cu
& Zn downstream).

For the full report, please go to

Mr. Andrew Gourlay, P. Geol., President of Andean American Mining Corp. is a Qualified Person as defined in the Canadian Securities Administrators National Instrument 43-101 with the ability and authority to verify the authenticity and validity of technical and scientific data. This news release has been prepared under Mr. Gourlay's supervision.

On behalf of Andean American Mining Corp.,

John Huguet, Chairman & CEO

Andean American Mining Corp. (TSX VENTURE:AAG)(FRANKFURT:AQN)(BVL:AAG) is an international mining and exploration company focused on growth. The Company is actively pursuing new targets of potential early stage gold and silver prospects in Peru and currently has two key assets: the 41,500 hectare Invicta gold-silver-copper advanced exploration stage project; 61% of Sinchao Metals Corp., owner of the Sinchao zinc-copper-silver-gold-lead mineralization project.

This news release may contain forward-looking information within the meaning of the Securities Act (Ontario) ("forward-looking statements"). Such forward-looking statements may include the Company's plans for its mineral projects, the overall economic potential of its properties, the availability of adequate financing and involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements expressed or implied by such forward-looking statements to be materially different. Such factors include, among others, risks and uncertainties relating to potential political risks involving the Company's operations in a foreign jurisdiction, uncertainty of production and costs estimates and the potential for unexpected costs and expenses, physical risks inherent in mining operations, currency fluctuations, fluctuations in the price of gold and other metals, completion of economic evaluations, changes in project parameters as plans continue to be refined, the inability or failure to obtain adequate financing on a timely basis, and other risks and uncertainties, including those described in the Company's Financial Statements, Management Discussion and Analysis and Material Change Reports filed with the Canadian Securities Administrators and available at

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