Resource estimates for Sunridge Gold (SGC-V, SGCNF-O) on its Debarwa and Adi Nefas massive sulphide projects in central Eritrea show a significant supergene copper concentration.
Debarwa, mainly a copper-gold deposit, holds 2.7 million tonnes of oxide material grading 0.21% copper and 0.09% zinc, with 1.9 grams gold and 14.5 grams silver per tonne. Below that, a supergene zone about 30 metres thick adds another 1.5 million tonnes grading 5.12% copper and 0.27% zinc, with 1.3 grams gold and 30 grams silver per tonne, and primary mineralization at depth contains 1.1 million tonnes at 2.17% copper, 3.21% zinc, 1.2 grams gold and 24.9 grams silver per tonne.
The low-grade oxides extend to about 80 metres depth. All the estimates are inferred resources.
At Adi Nefas, the main mineralization is an unweathered zinc-rich massive sulphide, with an inferred resource of 2.3 million tonnes averaging 1.46% copper, 6.7% zinc, 2.5 grams gold and 80.7 grams silver per tonne. There is an oxide cap of about 419,000 tonnes grading 0.38% copper and 0.36% zinc, with 2.7 grams gold and 41.4 grams silver, and a small supergene zone.
The oxide resource at Adi Nefas extends to 60 metres depth, and the supergene-enriched zone below it is about 20 metres thick.
The cutoff grades for the resources varied by zone, with oxide resources cut off at 0.5 gram gold per tonne, supergene material at 0.5% copper, and underground resources at 0.5% copper at Debarwa and 1% zinc at Adi Nefas.
The two deposits are in a three-block land package Sunridge holds around the Eritrean capital, Asmara. Adi Nefas is about 7 km north of the city and Debarwa about 30 km south; Sunridge’s current thinking is to develop the two together to take advantage of the infrastructure around the city.
Sunridge has commissioned a preliminary economic assessment, which should be out before the end of March.
There are two other prospects on the land package, the Gupo gold deposit, which has about 2 million tonnes grading 3 grams gold per tonne, and the Emba Derho massive sulphide, which has not had a resource estimate done yet. Drill results at Emba Derho have confirmed the deposit over a 900-metre strike length, and down to 300 metres vertical depth, and at its widest, the deposit is about 400 metres across.
Lundin Mining (LUN-T, LMC-X) holds a minority interest in Sunridge, which it acquired in a $5.2-million private placement in early 2006. Lundin also holds about 13% of another Eritrean explorer, Vancouver-based Sanu Resources (SNU-V, SNULF-O), which it acquired for $2.6 million.
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