APPENDIX II COMPETENT PERSONS REPORT FOR THE TOROMOCHO PROJECT
The following is the text of the competent persons report from the Competent Evaluator in respect of the Toromocho Project for the purpose of incorporation into this Scheme Document.
January 2017
CHINALCO MINING CORPORATION INTERNATIONAL Competent Persons Report for Toromocho Copper ProjectSubmitted to:
Chinalco Mining Corporation International
REPORTReport Number. 1660234-001-R-Rev2b
Distribution:
1 electronic copy - Chinalco
1 electronic copy - Golder Associates Pty Ltd
Executive SummaryGolder Associates ("Golder") was commissioned by Chinalco Mining Corporation International (Chinalco) to prepare a Competent Persons Report to assist Chinalco in its Independent technical review of the principal assets of Minera Chinalco Perú (MCP). The project is located in Peruvian Andes approximately 140 km east of Lima. In August 2007 Chinalco acquired all the shares of Peru Copper Inc., owner of Minera Peru Copper, which is now Minera Chinalco Peru S.A, and on 5 May of the following year (2008) signed the transfer of concessions and mining assets contract of the Toromocho Copper Project.
The information, observations, and conclusions in this Competent Persons Report (CPR) that relate to Mineral Resource and Ore Reserve estimation and classification are provided in accordance with, and conform to the conventions of, the Australasian Code for Reporting of Exploration results, Mineral Resources and Ore Reserves (JORC Code, 2012 Edition). Dr Sia Khosrowshai reviewed the Mineral Resources for the Toromocho Copper Project. Mr Glenn Turnbull reviewed the Ore Reserves and applied modifying factors.
Both Dr Khosrowshahi and Mr Turnbull are current Members of the Australasian Institute of Mining and Metallurgy (The AusIMM) and are competent persons in their respective fields under the JORC 2012 code. Mr Damian Connelly is a Principal Consulting Engineer with over 28 years' experience as a Consultant Metallurgist. Mr Connelly is a current Member of the Australasian Institute of Mining and Metallurgy (The AusIMM) and a competent person in his respective field.
The Mineral Resource and Ore Reserve estimates used in this report are information as at
31st December 2015. Chinalco has not advised Golder of any material change, or event likely to cause material change, to the Mineral Resource and Ore Reserve estimates.
The project commenced ore feed to the Crusher in December 2013 with copper concentrate being produced throughout 2014 and 2015. Tonnage build up within the process plant has been rapid with some 84% of design throughput having been achieved in 2015. The annual production metrics for the process plant for 2014 to 2015 are shown below (Table A).
Table A: Toromocho Project production statistics 2014-2016
2014 | 2015 | 2016 (Estimate) | |
High Grade Mill Ore (Mt) | 19.7 | 36.1 | 38.3 |
Low Grade Mill Ore (Mt) | 1.1 | 0 | 2.7 |
Total Mill Ore (Mt) | 20.8 | 36.1 | 41.0 |
Head Grade Cu (%) | 0.562 | 0.538 | 0.604 |
Head Grade Ag (g/t) | 7.31 | 6.416 | 5.416 |
Copper Recovery (%) | 60 | 83.08 | 79.86 |
Recovered Metal (Cu Tonnes) | 70,263 | 161,518 | 197,754 |
Concentrate Dry Tonnes | 297,698 | 676,449 | 833,977 |
Arsenic Grade in conc. (%) | No Data | 1.047 | 0.865 |
Although tonnage build up has been relatively satisfactory, the metallurgical recovery in 2016 has been lower than expected primarily because of issues with talc in the ore feed (Table B). The high Arsenic in concentrate has resulted in high penalty costs for treatment and refining costs. The molybdenum circuit has not been commissioned to date but is understood to be well advanced.
During 2016 the process plant has to date not achieved the expected recoveries and has been below expected throughput levels; it is however expected that the two are inter-related.
It would appear that the estimated recovery for 2016 might also be optimistic as average recoveries during 2016 for the first five months only equated to 72.96%. The lower throughputs noted by the process plant
staff in terms of SAG mill performance appears to be directly related to the proportion of potassic material in the feed.
The potassic ore requires greater comminution effort in the initial phase (drilling and blasting) in order to ensure that the throughput at the SAG mill stage is not compromised. When blasting in the potassic material it is important to consider the overall total cost of operation to ensure that for example lower throughput does not result from a cost reduction in say drilling and blasting.
Table B: 2016 Actual performance January to May
Production 2016 | Jan | Feb | March | April | May | YTD | |
Tons milled | DMT (kt) | 2 770 | 2 230 | 2 401 | 2 973 | 3 064 | 13 439 |
Head Grade - Cu | % | 0.61 | 0.51 | 0.58 | 0.60 | 0.64 | 0.59 |
Cu Recovery in Cu concentrate | % | 73.63 | 77.03 | 73.08 | 72.22 | 70.61 | 72.96 |
Head Grade - Ag | g/t | 6.14 | 6.90 | 5.98 | 7.22 | 7.13 | 6.70 |
Ag Recovery in Cu concentrate | % | 59.71 | 69.40 | 64.97 | 58.96 | 55.59 | 61.03 |
Head Grade - Mo | % | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 |
Head Grade - Zn | % | 0.09 | 0.10 | 0.11 | 0.09 | 0.14 | 0.11 |
Head Grade - As | % | 0.03 | 0.04 | 0.03 | 0.04 | 0.03 | 0.03 |
Copper Concentrate Produced | DMT | 55 693 | 40 232 | 52 658 | 68 881 | 72 382 | 289 847 |
Grade - Cu | % | 22.26 | 21.82 | 19.43 | 18.55 | 19.15 | 20.03 |
Grade - Zn | % | 3.23 | 4.47 | 3.65 | 2.79 | 3.83 | 3.53 |
Grade - As | % | 0.82 | 1.20 | 0.83 | 0.92 | 0.65 | 0.86 |
Copper content | DMT | 12 398 | 8 779 | 10 231 | 12 778 | 13 864 | 58 049 |
Of primary concern is the continuing issue with lower than expected recovery of copper. The copper will account for some 80% of the recoverable value from the project over the life of the mine and thus maximising the metallurgical recovery from the copper is vitally important. Ramp-up and commissioning has also coincided with a decline in copper prices that has resulted in significant financial pressure on the project. Total capital cost to date for the project has amounted to some $4B including finance charges.
In reviewing the Toromocho Project, Golder believes that the overall project remains technically sound, but has reservations about the ability of the project to deliver a satisfactory return on investment without the Expansion Option case. Taking the Toromocho Project as it stands today with a mill design throughput of some 42.8 Mtpa in all but the most optimistic pricing scenarios fails to meet a satisfactory level of financial return. Whilst the expanded case option, targeting some 62.0 Mtpa appears to be more financially attractive, it would seem unwise to commit to any further expansion currently until a full understanding of the talc recovery issues and future mitigation of arsenic levels in concentrate are better understood.
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