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Caribou Mine & Mill

2014 Caribou Preliminary Economic Assessment (amended 2015)
2013 Technical Report

Trevali's wholly-owned Caribou Mine and Mill Complex consists of a developed underground mine with significant resources of zinc-lead-silver-copper-gold, a fully permitted 3,000-tonne-per-day processing mill, flotation recovery plant, metallurgical and geochemical laboratories, and a tailings treatment facility, all located approximately 50-km west of Bathurst, New Brunswick, Canada.

Caribou commissioning commenced in mid-2015. (Please review Disclaimer)


The Caribou project is located in Restigouche County in the Province of New Brunswick, approximately 50 kilometres west of Bathurst. The 3,105.7-hectare property is approximately 7-km long in the east-west direction and 5-km wide in the north-south direction. The north-eastern and northern limits of the property are intersected by Provincial Highway 180.

Caribou Commissioning and Operations

Caribou Mill - key commissioning & preliminary production statistics (figures rounded)
  Q3-2015 Q4-2015
Tonnes Mined 114,386 160,511
Tonnes Milled 203,401 165,605
Average Mill Tonnes-per-day (TPD) 2,210 2,020
Average Head Grades %    
Zinc 4.8% 6.0%
Lead 1.8% 2.2%
Silver - Oz (ounces)/ton 1.6 oz/t 2.0 oz/t
Average Recoveries %    
Zinc 61.1% 71.5%
Lead 41.0% 57.2%
Silver (in Lead concentrate) 20.6% 29.5%
Concentrate Produced DMT (dry metric tonnes):    
Zinc 12,464 14,616
Lead 4,240 5,230
Concentrate Grades %    
Zinc 48.8% 47.6%
Silver - Oz (ounces)/ton (in zinc concentrates) 3.9 oz/t 4.2 oz/t
Lead 35.7% 39.8%
Silver - Oz (ounces)/ton (in lead concentrates) 16.1 oz/t 17.7 oz/t

Caribou PEA Study and Resources

The Caribou underground mine has significant underground development workings and mineral resources. It is a massive sulphide zinc-copper-lead-silver+/- gold deposit. SRK Consulting (Canada) completed a resource estimate for the Caribou project, outlining seven high grade mineralized lenses, documented in "Independent Technical Report for the Caribou Massive Sulphide Project, Bathurst, New Brunswick, Canada", and also completed a
Preliminary Economic Assessment ("PEA") of Caribou that outlined positive results for the commissioning of operations that commenced in May 2015.

The base case PEA indicates positive economic results for the Caribou underground mining operation and mill complex with a pre-production capital expenditure of $36.3 million, a post-tax Internal Rate of Return ("IRR") of 56.9%, post-tax Net Present Value ("NPV") of $106 million at a 5% discount rate, and average annual payable production of approximately 93 million lbs. zinc, 32.5 million lbs. lead, 3.1 million lbs. copper, 730,000 ozs. silver and 1,500 ozs. gold (Table 1).

Caribou Mine Project Preliminary Economic Assessment Highlights:
(based on US$1.00/lb Zn, US$1.00/lb Pb, US$3.00/lb Cu, US$21/oz Ag, US$1200/oz Au and Canadian dollar exchange rate of US$0.95)
  • Pre-tax IRR of 69% with a 1.9-year payback
  • Post-tax IRR of 56.9% with a 2.1-year payback
  • Pre-tax NPV(5%) of $150 million
  • Post-tax NPV(5%) of $106 million
Production Costs
  • Direct LOM Cash Costs of US$0.46/lb zinc equivalent
  • Total Site Operating Cost of $74.77/tonne milled (includes mining, milling, G&A and Environmental)
  • Pre-production capital of $36.3 million
Production (Payable)
  • Average annual payable production of 93 million lbs. Zn, 32.5 million lbs. Pb, 3.1 million lbs. Cu, 730,000 ozs. Ag and 1,500 ozs. Au
Mine Life
  • Planned mine life of 6.3 years (“LOM”)
  • Average LOM recoveries of 84% for Zn, 65% for Pb, 45% for Cu, 37.5% for Ag and 10.6% for Au used in the model
Table 1: Caribou Mine Project Base Case PEA Highlights

* The estimated plant feed is partly based on Inferred Mineral Resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as Mineral Reserves, and there is no certainty that the preliminary economic assessment based on these Mineral Resources will be realized.

The PEA is considered preliminary in nature and includes economic analysis that is based, in part, on inferred mineral resources. Inferred mineral resources are considered too speculative geologically to have the economic considerations applied to them that would allow them to be categorized as mineral reserves, and there is no certainty that the results will be realized. Mineral resources are not mineral reserves because they do not have demonstrated economic viability.

2013 Capped Measured, Indicated and Inferred Mineral Resources at the Caribou Project as prepared by SRK Consulting (Canada) Inc. using 5% ZnEq* cutoff grade:
Caribou Resource Tonnes %Zn %Pb %Cu Ag (gpt) Au (gpt) Zn (Mlbs) Pb (Mlbs) Cu (Mlbs) Ag (Moz) Au (Moz)
  Contained Metal
Measured and Indicated Resources
Inferred Resources
*ZnEq= ((Cu Grade*Cu Price*Cu Recovery)+(Pb Grade*Pb Price*Pb Recovery)+(Zn Grade*Zn Price*Zn Recover)+(Au Grade*Au Price*Au Recovery)+(Ag Grade*Ag Price*Ag Recovery))/Zn Price. In calculating ZnEq, SRK Consulting (Canada) Inc. utilized the long term metal prices provide by Energy & Metals Consensus Forecast. Price for Au is $1470 per ounce, Ag is $26 per ounce, Cu is $3.39 per pound, Pb is $1.18 per pound, and Zn is $1.14 per pound. A recovery of 83% was applied to Zn, 71% was applied to Pb, 57% was applied to Cu, 45% was applied to Ag, and 40% was applied to Au. The pounds of metal are in-situ and have not had any mining factors applied to them.. (Please review Disclaimer)

Previous Operations

Between 2006 and 2008, the previous operator of the Caribou mill and mine complex invested approximately $100 million in a major overhaul and modernization of the processing plant and mine infrastructure (including new state-of-the-art milling and grinding components -- IsaMills and On-Stream analysers to optimize recoveries). The mine operated for approximately 13 months prior to going into receivership in 2008 due to depressed commodity prices and adverse global financial conditions.

Caribou Geology

Caribou is a volcanic-sediment-hosted massive sulphide deposit and is one of over 45 massive sulphide deposits in the Bathurst Mining Camp. The deposit is situated in the northern portion of the Bathurst Mining Camp and occurs in the core of a synformal structure that plunges steeply (80°- 85°) to the north.

The Caribou deposit consists of the following units from the base upward:
  1. Dark gray to black carbonaceous shale, pale gray phyllite, graywacke, and chloritic schist interbedded with hydrothermally altered pale green felsic volcanic rocks (footwall of the deposit);
  2. Stringer sulphides cutting hydrothermally altered sedimentary and felsic volcanic rocks;
  3. Massive sulphides comprising a vent complex and bedded sulphides;
  4. Chloritic schist at the contact between massive sulphides and overlying felsic volcanic rocks;
  5. Interbedded felsic volcanic and sedimentary rocks.