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NEWMONT POURA DEPOSIT (24t Au produced)

13 November 2013

POURA DEPOSIT

Project Location and Access

The Poura mine is located in the Mouhoun Province of southwestern Burkina Faso. It is about 180 kilometers southwest of the capital Ouagadougou .

Poura site is accessed from the capital via paved highway to Poura junction on the Ouagadougou-Bobo Dioulasso rood and then 20 kilometers of lateritic road to the site.

Project History

  • Artisanal miners (orpailleurs) exploited Poura’s mineral resources long before a modern mine was established in 1939. They exploited auriferous quartz veins and paleo placers.
  • Between 1939 and 1949, two French companies used a small mill for reprocessing the orpailleur tailings. Both companies extracted about 250 kg of gold.
  • From 1949 to 1961, a French syndicate explored the deposit using 80 holes,
  • In 1961, underground mining began using shrinkage stopping method. Operations ceased in 1966 for economic reasons. In total, 5,600 kg of gold was produced.
  • Exploration work in 1974 revealed 1.6 million tonnes of ore with an average grade of 13.5 g/tonne. In 1977, a feasibility study was completed that recommended re-opening the underground mine.
  • SOREMIB was formed in 1973 to resume the operation of the Poura gold mine. The ore processing plant was inaugurated in 1984 and the open pits were exhausted by 1988.
  • Ashanti Goldfields in 1996 optioned the mine to Sahelian International Goldfields that continued underground exploration and rehabilitated the surface facilities.
  • The Poura mine closed in 1999, after the fall of the gold  price.
  •  Minister of Mines signed a convention on 1st June 2012 with Newmont Ventures Limited for the restarting of activities at Poura gold mine by reconstruction of the mine .
  • Exploration work by Newmont is ongoing on various prospects

 Geology

The Poura mine is located in the center of the Boromo-Goren greenstone belt that strikes in a north to northeast direction.

Rock units comprises from oldest to youngest:

–         The footwall that consists of dark green volcaniclastic rocks, thicker than 200m. They comprise welded tuffs, lapillis, pyroclastic breccias, and doleritic basalts with quartz veinlets and pinkish carbonate.

–          Younger detrital sedimentary formations, 20-200 m thick, form the hanging wall. The ore is often fully surrounded by them. They consist of conglomerates, greywackes, with periodic intercalations of chert. The top consists of sandstones, chert, and pelites (banded siltstone-mudstone with typical turbiditic structures).

–         Volcanic rocks, thicker than 200m, overlie the detrital formations. They consist of massive andesite flows, ash tuffs, lapilli tuffs, pyroclastic breccias, conglomerates, and volcanic dykes that cut the conglomerates.

 DEPOSIT TYPE

Poura gold district, includes a significant Lode field extending NW – SE strike. This main mineralization is mesothermal gold-bearing quartz veins within structure controlled by a shear zone. That deposit type is common in the Proterozoic of Burkina Faso.

The Poura Vein Network is constituted of 3 mains veins. The crude ore is a lode of fractured massive quartz in which the Au is chiefly deposited in fissures.

MINERALIZATION

The ore consists of three principal steeply-dipping quartz veins. These are the Filon Plaine, Filon Montagne, and Filon Ouest. There are also several minor related veins. Filon Plaine is economically the most important and is the focus of historic production. It has a strike length of 2000m and it is oriented N-S to N25 °.

The ore is a quartz vein with silver-bearing (11 % average silver content), native gold and a minor percentage of polymetallic sulphides. The deposit is oxidized and weathered down to one hundred meters by supergene alteration.

Most of the gold is free-milling, but a small percentage is locked in the sulphides (refractory)

Mineral Resource and Mineral Reserve

Summary statistics of kriging results (Sahelian Goldfields  1999).

The average (volume-weighted) mean grade was calculated as 14.85 g/tonne. The average (volume-weighted) mean block thickness was calculated as 1.86 metres. Resources were calculated using each block’s estimated mean grade and thickness.

Area (m2)

Volume (m3)

Ressource Mass (tones)

Gold Mass (g)

Poura Deposit

94668

176519

467776

6945778

Avg Grade (g/t): 14.849 Average Thickness  (m): 1.865

 NB: Most of the figures are modified from company public data

 http://newmont.com/

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13 November 2013
13 November 2013

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