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| Buryatzoloto ownership: |
100% |
| Mine type: |
Underground |
| 2005 gold production: |
83,280 oz |
| 2005 total cash cost: |
US$244/oz |
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Aerial view of the Irokinda mine
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The Irokinda mine is a producing underground operation located in the Republic of Buryatia, Russia approximately 680 kilometres northeast of Ulan-Ude. Access to the mine is by an 80 kilometre gravel road from the Taksimo railway station of the Baikal-Amur Railroad. The Zun-Holba mine site has excellent infrastructure and is served by the local low-cost power grid.
Geological Setting and Mineralization
Auriferous mineralization at the Irokinda property is localized along numerous moderately dipping, low sulphide quartz veins hosted in Archean gneiss, which have been cut by dioritic intrusive bodies, and more recently discovered in gabbroic rocks. Individual veins have strike lengths ranging from 60 metres to 1.5 kilometres with pinch and swell characteristics and varying from 0.1 to 5 m in thickness. The veins are generally traced for over 300 metres down dip. Gold mineralization is discontinuous with local rich bonanza-type ore shoots measuring from 30 to 120 metres along strike and up to 250 metres down dip. Historically, 16 veins have been exploited containing an average of 50,000 ounces of gold. The gneissic wall rock has been altered and is not mineralized.
History
Auriferous mineralization was initially discovered at Irokinda in 1959. Between 1962 and 1974, extensive exploration of the area resulted in the discovery of over 100 gold-bearing veins. Mining operations commenced at the site around 1985. Buryatzoloto acquired the license on the Irokinda project in 1991 and became the operator of the mine in 1996, when the subcontractor's (Vitim Partners) mining contract expired.
Mining
Access to underground workings
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Ore is extracted from several vein structures, which are accessed by a series of adits and internal shafts. Most ore production occurs at the adit levels.
The room and pillar mining method is used.
| Operational Data |
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2005 |
2004 |
| Tonnes mined |
329,080 |
327,014 |
| Tonnes milled |
300,317 |
308,127 |
| Head grade (g/t) |
9.1 |
9.1 |
| Recovery (%) |
95.3 |
95.0 |
| Gold production (oz) |
83,280 |
85,484 |
| Direct Mining Costs |
$215 |
$188 |
| Total Cash Cost |
$244 |
$214 |
Since High River's initial share purchase in 1995 to year-end 2004, the mine has produced a total of 510,997 ounces of gold. The following table shows historical production at the mine:
|
2004 |
2003 |
2002 |
2001 |
2000 |
1999 |
1998 |
1997 |
1996 |
1995 |
| Tonnes Mined |
327,014 |
287,929 |
245,972 |
235,816 |
158,538 |
106,556 |
83,492 |
87,620 |
96,784 |
58,057 |
| Tonnes Milled |
308,127 |
255,913 |
234,609 |
220,691 |
152,106 |
96,786 |
85,284 |
83,057 |
96,128 |
62,888 |
| Head Grade (g/t) |
9.11 |
10.7 |
11.4 |
10.9 |
11.4 |
11.4 |
12.8 |
11.9 |
9.0 |
9.6 |
Gold Pro-
duction (oz) |
85,484 |
83,943 |
81,367 |
73,129 |
52,256 |
33,087 |
32,190 |
28,669 |
24,882 |
17,531 |
Processing
Tracked mining at Irokinda
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Conventional gravity and flotation techniques are employed at the Irokinda plant. The mill capacity is 269,000 tonnes per year with the recent commissioning of a new crusher and the expansion of the flotation circuit. Approximately 70% of the gold production at Irokinda is recovered by gravity. The remainder is derived from flotation concentrates. The flotation concentrate is transported by train or truckto the Zun-Holba treatment plant where the gold is recovered in the CIP plant.
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