Mineral Resources:
The Mineral Resource estimate of La Arena Project prepared in accordance with NI 43-101 on behalf of Rio Alto by Qualified Persons, as described in the La Arena Project, Peru Technical Report (NI 43-101) with an effective date of September 30, 2011 is outlined in the following tables:
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Table 1.7_1 Mineral Resource – Oxide Total (In Situ as at September 30th 2011) Within Optimised Pit Shell |
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|
Resource |
Tonnes (Mt) |
Au (g/t) |
Cu (%) |
Ag(ppm) |
Mo(ppm) |
Au (‘ooo Oz) |
Cu (‘000 lbs) |
|
Measured Indicated |
10.3 90.4 |
0.67 0.43 |
0.01 0.02 |
0.6 0.5 |
8.3 11.7 |
221 1,263 |
NA NA |
|
Measured and Indicated |
100.7 |
0.46 |
0.02 |
0.5 |
11.4 |
1,484 |
NA |
|
Inferred |
10.4 |
0.27 |
0.01 |
0.5 |
13.1 |
90 |
NA |
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Table 1.7_2 Mineral Resource – Sulphide Total (In Situ as at September 30th 2011) Within Optimised Pit Shell |
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|
Resource |
Tonnes (Mt) |
Au (g/t) |
Cu (%) |
CuEq (%) |
Ag(ppm) |
Mo(ppm) |
Au (‘ooo Oz) |
Cu (‘000 lbs) |
|
Indicated |
312.7 |
0.24 |
0.29 |
0.48 |
0.7 |
42.9 |
2,422 |
2,007,000 |
|
Inferred |
319.7 |
0.20 |
0.30 |
0.46 |
0.6 |
46.1 |
2,075 |
2,134,000 |
Mineral Reserves:
There has not yet been an update of Mineral Reserve estimates since the La Arena Project, Peru – Technical Report by Coffey Mining Pty Ltd prepared on behalf of Rio Alto with an effective date of July 31, 2010. Due to the update to the Mineral Resources with an effective date of September 30, 2011; the gold oxide dump leach project moving into commercial production; and a Feasibility Study of the copper-gold sulphide project having recently commenced, Reserves will be updated in due course.
The Probable Mineral Reserves of the La Arena Project prepared in accordance with NI 43-101, based on the Indicated Resource only, as at July 31, 2010 is given in the following table.
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The Mineral Reserve has been estimated including a 2% allowance for ore loss during mining and the following cut-off grades:
* For oxide ore with Cu<300ppm (dump leach feed) 0.11Au g/t
* For oxides with Cu>300ppm, secondary and primary sediments and porphyry (mill feed) 0.13%Cu.
The estimation and classification of the mineral reserves by Coffey Mining are in accordance with the guidelines set out in the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves of December 2004 as prepared by the Joint Ore Reserves Committee of the Australasian Institute of Mining and Metallurgy, Australian Institute of Geoscientists and Minerals Council of Australia (JORC). The reserve classification is also consistent with criteria laid out in the Canadian National Instrument 43-101, Standards of Disclosure for Mineral Projects of December 2005 (the Instrument) and the classifications adopted by CIM Council in November 2004. The reporting of reserve classification under the JORC Code and the Canadian NI 43-101 systems are essentially identical.
Information current as at February, 2012.