GoldMinerPulse Report: Rio Alto Mining Limited Metal Value

Rio Alto Mining Limited (RIO) NI 43-101 Metal Value Report

Rio Alto's primary focus for 2010 will be to build and operate a dump leach gold mine at La Arena in Peru.

On July 20, 2010, the company received approval for its Environmental Impact Study, which had been submitted in September 2009. With the EIA, the company has access to US$24.25M of funding for development. Quoting, CEO Alex Black:

Receipt of environmental approval and the awarding of the civil construction contract represent two major milestones in the La Arena development process. We have been extremely pleased with the responsiveness of the various government agencies during the EIA approval process and are encouraged by the support for the development of La Arena demonstrated by the local communities. We are also pleased to have selected a consortium of the caliber of G&M and Stracon as our civil construction contractor and look forward to working with them in bringing La Arena into production.

The Rio Alto Mining Limited web site is at www.rioaltomining.com.

Information Links: Yahoo News and Quotes | Yahoo Message Board | StockCharts | Stockhouse

CAUTION: This report has been prepared assuming that Rio Alto Mining exercises its options to acquire 100% of the La Arena project from IAMGold. Please see Peru .:. La Arena Project .:. Earn-in Agreement & Option Terms for the details on the IAMGold agreement.

Recent Company Headlines

Thu, Aug 26 Rio Alto Mining Limited: Corporate Update-Adoption of Shareholder Rights Plan [Marketwire more]

GoldMinerPulse Metrics Summary

This report is based on NI 43-101 resource and reserve disclosures and fully diluted share counts available on 2010-09-02.

The GoldMinerPulse metrics, presented below in table format, are based on all projects and all in situ metals and are updated daily with closing market prices.

**Rio Alto Mining Limited Metric Summary**
General Metric	Value on 2010-09-02
In Situ Metal Value per Share (MVpSh)	US$115.93
Average Ore Value per Tonne	US$34.68
Metal Value Leverage (MVL)	122.13
Market Capitalization as a Percentage of Metal Value	0.8%
Recent Closing Stock Price	C$1 [note 1]
Fully Diluted Share Count	134.51 M [note 2]
Percentage In Situ Proven + Probable Reserve	0%
Percentage In Situ Measured + Indicated Resource	61%
Percentage In Situ Inferred Resource	39%

**Gold Specific Metrics**
Metric	Value on 2010-09-02
Gold Reserves + Resources	4.31 M oz
Average Gold Ore Grade	0.3 g/t
Market Capitalization per oz of Gold In Situ	US$29.59 ( C$31.18 )
Gold Equivalent Ounces Estimate	12.46 M oz
Market Capitalization per oz of Gold Equivalent	US$10.25 ( C$10.79 )

Note 1: Conversion rate used: 1 Cnd$ = 0.949244 US$
Note 2: Fully diluted share count updated based on counts given at Share Structure web page (viewed September 2010).

GoldMinerPulse Most Optimistic Resource Estimate Summary (MORE)

All metal counts in this section are based on the combined Proven + Probable reserves plus the Measured + Indicated and Inferred resources.

**Metal Summary Based on Closing Prices on 2010-09-02**
Metric / Metal	Gold	Copper
Total Counts (reserves + resources)	4.31 M oz	1.34 M t
Metal Prices in US$ (from 2010-09-02)	$1,251.30 per oz	$3.46130 per lb
Metal Value per Share (MVpSh) Shown in US$. Based on fully diluted share count	$40.14	$75.79
Percentage of Total Metal Value	34.62%	65.38%
Metal Value Percentage Proven + Probable	0%	0%
Metal Value Percentage Measured + Indicated	65%	59%
Metal Value Percentage Inferred	35%	41%

The above metal value totals derive from the following projects.

**Project/Deposit/Mine Summary Based on Closing Prices on 2010-09-02**
Project	Location	Metal Value per share (% total)	Gold	Copper	PP%	MI%	I%
La Arena Sulphide	La Libertad, Peru	$107.29 ( 92.5% )	3.39 M oz	1.34 M t	0	58%	42%
La Arena Oxide	La Libertad, Peru	$8.64 ( 7.5% )	929.03 K oz		0	98%	2%

PP%: percentage of metal value from Proven + Probable reserves
MI%: percentage of metal value from Measured + Indicated resources
I%: percentage of metal value from Inferred resources
Note: percentages may no add to 100% due to rounding errors

La Arena Oxide

Latest NI43-101 Report: La Arena Project, Peru Technical Report
2008-06 (0 pages).

Updates: Reserves and resource figures taken from Peru .:. La Arena Project .:. Resource & Reserves web page viewed January 2010.

Project Location: La Libertad, Peru. View project on a Google Map.

Indicated

Metal	MVpSh	Contained Metal Quantity	Ore Grade	Ore Quantity
Gold	$8.50	913.72 K oz	0.490 g/t	58.00 M t
Silver	$0.02	167.83 K oz	0.090 g/t	58.00 M t

Estimate notes: See Peru .:. La Arena Project .:. Resource & Reserves.
Cuttoff is 0.15g/t Au.

This Valuation Report is prepared assuming that

Mexican Silver Mines and Rio Alto merge.
Mexican Silver Mines exercies its options to aquire 100% of the La Arena project from IAMGold.

Inferred

Metal	MVpSh	Contained Metal Quantity	Ore Grade	Ore Quantity
Gold	$0.14	15.30 K oz	0.280 g/t	1.70 M t
Silver	$0.00	19.13 K oz	0.350 g/t	1.70 M t

Estimate notes: See notes for Indicated.
Cuttoff is 0.15 g/t Au.

La Arena Sulphide

Latest NI43-101 Report: La Arena Project, Peru Technical Report
2008-06 (0 pages).

Updates: Reserves and resource figures taken from Peru .:. La Arena Project .:. Resource & Reserves web page viewed January 2010.

Project Location: La Libertad, Peru.

Indicated

Metal	MVpSh	Contained Metal Quantity	Ore Grade	Ore Quantity
Gold	$17.77	1.91 M oz	0.270 g/t	220.00 M t
Copper	$44.93	792.00 K t	3,600.000 g/t	220.00 M t

Estimate notes: See Peru .:. La Arena Project .:. Resource & Reserves.
Cuttoff is 0.1% Cu.

This Valuation Report is prepared assuming that

Rio Alto Mines exercies its options to aquire 100% of the La Arena project from IAMGold.

Inferred

Metal	MVpSh	Contained Metal Quantity	Ore Grade	Ore Quantity
Gold	$13.73	1.48 M oz	0.270 g/t	170.00 M t
Copper	$30.86	544.00 K t	3,200.000 g/t	170.00 M t

Estimate notes: See notes for Indicated.
Cuttoff is 0.15 g/t Au.