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| Buryatzoloto ownership: |
100% |
| Mine type: |
Underground |
| 2005 gold production: |
69,844 oz |
| 2005 total cash cost: |
US$306/oz |
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Aerial view of the Zun Holba mine
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The Zun-Holba mine is a producing underground operation located in the Republic of Buryatia, Russia, approximately 315 kilometres by road from the town Kultuk, a station on the Trans-Siberian Railroad, at the southwest end of Lake Baikal. The mine is accessible by a 90 kilometres gravel road from Mondy, the nearest community. The Zun-Holba mine site has excellent infrastructure and is served by the local low-cost power grid.
Geological Setting and Mineralization
The Zun-Holba deposit occurs within a northwest trending sequence of strongly folded and metamorphosed Proterozoic volcanics and sediments consisting of limestones, sandstones, schists and tuffs forming a septum between two Archean intrusives. The mixed volcano-sedimentary package hosts 13 subvertical, en echelon gold-bearing mineralized zones containing quartz-sulphide veins. The mineralized zones range from 0.3 to 8 metres in thickness, averaging about 2 metres. The mineralized zones are imbricated into a shear zone that is axial to the septum. Mineralization often occurs as branching en-echelon veins with strike lengths of 50 to 100 metres. The combined ore-bearing zones measure about 3 kilometres along strike and have been traced to a minimum depth of 1 kilometre.
Mineralization occurs in the host rocks and quartz veins and is associated with sulphides. In the massive orebodies, the sulphide content is 60-90%. Of the sulphides, pyrite constitutes 80% and chalcopyrite 15 to 20%. Sphalerite, galena and pyrrhotite are rare. In the quartz vein ore, sphalerite, pyrite and galena comprise up to 10%.
History
Administrative Building
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The Zun-Holba deposit was initially discovered in 1955. Mine development and initial limited production started in 1987. Buryatzoloto acquired the license for Zun-Holba in 1991 and assumed control of day-to-day operations from the sub-contractor of the project in 1993.
Mining
The Zun-Holba mine operates with a series of adits and internal shafts. Mining is currently focussing in the lower sections of the ore body, which are accessed by two internal shafts. These two internal shafts, sunk to 250 m below the level of Adit No. 12, were put into operation as scheduled during 2003. The shafts provide access to development and production work on five lower shaft levels.
Mining methods currently used at Zun-Holba are shrinkage stoping and cut and fill stoping.
| Operational Data |
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2005 |
2004 |
| Tonnes mined |
247,973 |
235,540 |
| Tonnes milled |
240,958 |
225,208 |
| Head grade (g/t) |
9.3 |
9.5 |
| Recovery (%) |
93.0 |
93.7 |
| Gold production (oz) |
69,844 |
65,017 |
| Direct Mining Cost |
$274 |
$267 |
| Total Cash Cost |
$306 |
$297 |
From High River's initial investment in 1995 to year-end 2004, Zun-Holba has produced 609,552 ounces of gold. The following table shows historical production at the mine since 1995:
|
2004 |
2003 |
2002 |
2001 |
2000 |
1999 |
1998 |
1997 |
1996 |
1995 |
| Tonnes Mined |
235,540 |
229,098 |
233,098 |
222,232 |
225,528 |
216,021 |
190,858 |
200,820 |
192,692 |
151,984 |
| Tonnes Milled |
225,208 |
229,332 |
227,366 |
230,796 |
220,646 |
215,502 |
194,947 |
203,421 |
207,678 |
193,035 |
| Head Grade (g/t) |
9.5 |
9.5 |
10.1 |
10.1 |
10.8 |
10.2 |
11.3 |
9.9 |
8.3 |
6.7 |
Gold Pro-
duction (oz) |
65,017 |
65,267 |
68,606 |
69,647 |
70,801 |
65,000 |
63,046 |
57,142 |
48,886 |
36,110 |
Processing
A carbon-in-pulp ("CIP") plant, to recover gold from a flotation concentrate, was commissioned at Zun-Holba in 1998 in order to eliminate the high transportation costs associated with shipping the concentrates. Gold doré bars are produced on site. The flotation concentrate produced at Irokinda is transported to the Zun-Holba CIP plant for processing to doré.
The Company is optimistic about the potential to extend the current mine life of the Zun-Holba operation, as the mineralized system is open along strike and down plunge. Buryatzoloto and High River are undertaking a number of initiatives including a more aggressive drilling programme in the existing mine workings and deeper levels, and adjacent to the mine where, for example, there are a number of exploration targets that have been identified along a six-kilometre structure extending on strike to the southeast from the Zun-Holba mine. Targets closer to the mine are also being carefully evaluated.
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