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Caribou Mine & Mill

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 60-km west of Bathurst, New Brunswick, Canada.

Restart of Trevali's Caribou operation is underway with planned commissioning in early 2015. The scheduled capital expenditure for the restart is approximately $35 million (approximately $20-million for mill and $15-million for underground development) and will be financed with the Company's current cash and debt facility.

Trevali acquired Caribou in late-2012 form a private group that owned the asset. (see Acquisition Overview for the terms.)

This strategic acquisition gives Trevali a number of synergistic benefits, including:
  • Provides Trevali with a modern, state-of-the-art 3,000-tonne-per-day processing plant (that will produce zinc, lead and copper concentrates), and includes a metallurgical and geochemical laboratory, and permitted tailings treatment facility.
  • Addition of a former-producing mine with significant underground development workings and historic resources that can be rapidly and cost-effectively brought on-line. The deposit remains open for expansion and Trevali classifies the upside potential as good to excellent: the deepest underground intercept to date returned 34.77 metres at 7.22 per cent zinc, 2.69 per cent lead, 0.25 per cent copper, 76.8 grams per tonne silver and 2.19 g/t gold.
  • Very significant financial, technical and timing de-risk versus permitting and building a new stand-alone Milling complex for the Company's Halfmile and Stratmat deposits.
  • Preferable from a social and sustainability perspective -- near-term creation of approximately 250 full-time employment positions, establishing Trevali as one of the larger employers in northern New Brunswick, and utilization of a working brownfield industrial site versus a greenfield site.
  • Due to superior quality of the Halfmile-Stratmat mineralization (coarser mineralogy with good metallurgical characteristics), modelling of the mill grinding circuit indicates it is readily modifiable to produce saleable zinc, lead (silver) and copper (gold) concentrates.
  • Further strengthens and confirms Trevali's position as a near-term intermediate zinc producer.
(Please review Disclaimer)


The Caribou milling and mine complex located in the Bathurst Mining Camp of northern New Brunswick, Canada, approximately 50km west of Bathurst and along Provincial Highway 180.


Caribou Deposit and Mill

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
Table 1: Caribou 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)

Between 2006 and 2007, the previous operator of the Caribou mill and mine complex invested approximately $100-to-120 million in a major overhaul and modernization of the processing plant and mine infrastructure (effectively new state-of-the-art milling and grinding circuits -- Isa Mills 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.

Immediately prior to shut down, mill records indicate recoveries of 71% Pb and 83% Zn to produce saleable concentrates. Historically no copper concentrates were produced, which represents additional near-term upside as Trevali intends to add a copper circuit to the processing plant.

Trevali believes that the current defined deposit contains excellent exploration potential and production can be fast-tracked to feed the Caribou Mill. Specific upside includes:
  • Currently defined deposit remains open along strike and at depth.
  • Silver and gold may be under-estimated by up to 20-30% as there was no routine precious metal analysis in historic drill holes.
  • Significant copper 'feeder' zones were not previously mined due to lack of a copper circuit in the mill. Trevali plans to add a copper circuit to the mill.

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.

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