Bisha Mine

Overview

Bisha Mine Location

Bisha is a large, high-grade volcanogenic massive sulphide (VMS) deposit located 150km west of Asmara, Eritrea, East Africa. The Bisha Mine benefits from high grade base metal reserves, strong support of the Government of Eritrea and an advantageous location with good local road and port infrastructure.

The Bisha Mine began construction in September 2008 and declared commercial production in February 2011 at a rate of 2Mtpa. The mine produced low-cost gold-silver doré until mid-2013 when, through a $110 million copper expansion, throughput expanded to 2.4Mtpa and the product switched to copper in concentrate. Later in the mine life flotation capacity will be expanded again to also produce zinc concentrates.

For more on production forecasts and profile, please see payable production.

Bisha's mining and exploration licenses cover an area of 78.8 km2. The Bisha Main deposit is located within the Bisha Mining License and the Harena satellite deposit lies in a separate Mining License 6km south, connected by a flat unsealed road. Bisha Main and Harena currently make-up 100% of the reserves for Bisha.

View Resource and Reserves.

The Bisha VMS Camp remains underexplored and holds strong potential for expanding resources for the Bisha mill. In February 2014, Bisha added resources from two satellite deposits, Hambok and Northwest Zone at a cost of discovery of $0.04 per lb of copper equivalent in indicated resources.

In 2014 Bisha is pursuing an aggressive greenfield exploration program to discover more satellite deposits. For more see Exploration.

The State of Eritrea has a free carried 10% interest plus an additional 30% paid participating interest for a total of 40% interest in Bisha. For more see About Eritrea.

Bisha Mine and Plant

Bisha is mined using conventional drill and blast open mining techniques to the run-of-mine (ROM) stockpile. See photo gallery for latest pit and mining operations pictures.

Mined ore is reclaimed from the ROM stockpile and fed to the conventional single stage crushing/SAG/ball mill comminution circuit.

Copper Floatation Flowsheet

The copper flotation plant is a conventional circuit with rougher cleaner regrind. See flowsheet to the left or click here. Copper concentrate is thickened, dewatered and stockpiled for shipment. Tailings are stored wet in the lined tailings management facility.

Power is provided to the Bisha plant by dedicated diesel generators. Water is sourced from pit de-watering and from local well fields.

Concentrate Export Infrastructure

Concentrate is being exported using a proven system with industry leading environmental controls. Concentrate is loaded from the dewatered stockpile, sealed in custom half-height shipping containers and transported to the port of Massawa by truck. The sealed containers are stockpiled in Massawa at the container port facilities. The Rotainer crane system then discharges the containers into bulk vessels and the containers are returned to Bisha for re-loading. The bulk vessels deliver the concentrate to copper smelters worldwide.

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Resources & Reserves

The Bisha Main deposit is a high grade VMS deposit. It is configured in three distinct layered zones - a 35m thick surface gold-silver oxide zone (mined out in mid-2013) immediately overlying a copper enriched supergene zone which itself overlies a primary sulphide zone containing both zinc and copper, which is open to depth.

See deposit configuration and payable production estimates below.

Mineral Reserves (Bisha and Harena)

Effective December 31, 2013

  Probable Reserves
  Tonnes
(1000's)
Copper
%
Zinc
%
Gold
g/t
Silver
g/t
Oxide 510 - - 6.25 19
Supergene 7,400 3.57 - 0.61 27
Primary 19,550 1.00 5.54 0.67 45
Total Probable Reserves 27,460

Mineral Reserves are defined within a mine plan, with phase designs guided by Lerchs-Grossman (LG) Pit Shells, generated using metal prices for copper, zinc, gold and silver of $2.90/lb, $0.92/lb, $1175/oz, $20/oz respectively.

For more details resources and reserves including assumptions, please click here.

Mineral Resources

Effective December 31, 2013

    Indicated Inferred
    Tonnes
(1000's)
Copper
%
Zinc
%
Gold
g/t
Silver
g/t
Tonnes
(1000's)
Copper
%
Zinc
%
Gold
g/t
Silver
g/t
Oxide                    
  Bisha 410 - - 6.8 21 30 - - 7.3 39
  Harena 70 - - 5.5 14 20 - - 5.9 8
  Northwest - - - - - 500 - - 3.7 19
  Hambok - - - - - 20 - - 1.5 17
  Total 480 - - 6.6 20 570 - - 3.9 19
Supergene                    
  Bisha 7,460 3.7 - 0.6 27 10 7.2 - 0.1 10
  Harena - - - - - - - - - 0
  Northwest 1,020 1.5 - 0.2 10 100 0.8 - 3.7 19
  Hambok - - - - - - - - - 0
  Total 8,480 3.4 - 0.6 25 110 1.4 - 3.4 18
Primary                    
  Bisha 21,070 1.1 5.9 0.7 47 1,300 0.8 4.5 0.5 4
  Harena 1,800 0.7 3.9 0.6 23 350 0.8 4.1 0.8 32
  Northwest 2,530 1.0 1.1 0.3 13 100 0.9 0.9 2.9 15
  Hambok 6,860 1.1 1.9 0.2 10 2 0.9 0.2 0.2 8
  Total 32,260 1.0 4.6 0.6 36 1,752 0.8 4.2 0.7 33
Total Resources 41,220 2,432

Mineral Resources are defined within an optimal Lerchs-Grossman (LG) Pit Shell, generated using metal prices for copper, zinc, gold and silver of $3.35/lb, $1.09/lb, $1350/oz, $23/oz respectively using blocks of all Resource categories.

For more details resources and reserves including assumptions, please click here.

A full description of the Bisha mineral resource and metallurgy may be found in the Company's Technical Report.

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Deposit Configuration

3D Model - Bisha   Interactive Cross Sections
 

Payable Production

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Technical Reports

March 2014
  Bisha Technical Report - 43-101- effective December 31, 2013

 

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