The Myra Falls mine is located in a provincial park in central Vancouver Island, British Columbia (
view map). The mine is linked by an asphalt road to the port of Campbell River, 90 kilometres away.
There have been over 100 years of mineral exploration activity in central Vancouver Island and over three decades of active mining at Myra Falls.
Active mining has been carried out at Myra Falls since 1966 starting with the Lynx open pit and underground operations, followed in 1969 with the Myra mine. In 1979, the H-W massive sulphide deposit was discovered prompting the installation of new infrastructure and an expansion of the milling facilities to 2,700 tonnes per day. This was later increased to 3,650 tonnes per day. In 1991, the Battle and Gap deposits were discovered. The Lynx underground mine closed in 1993. In 1995, the Marshall deposit was discovered. In 1996, mining in the Battle-Gap zone commenced.
Boliden Limited acquired the Myra Falls operation in January 1998. In July 2004, Breakwater Resources Ltd. purchased all the outstanding shares of Boliden Westmin (Canada) Limited from Boliden Limited.
The mineral deposits comprise complex metal-zoned volcanogenic massive sulphides contained in the 450m thick Myra Formation of the Sicker Group volcanic assemblage. The Myra Formation hosts a geologically diverse collection of mineralized bodies including polymetallic massive sulphides, polymetallic disseminated sulphides, zoned pyritic massive sulphides and stringer sulphide zones. The principal minerals are sphalerite, pyrite and chalcopyrite with minor galena, bornite, tennantite and locally significant secondary copper.
Summary of Mineral Reserves and Resources
|
|
31 December, 2007 |
31 December, 2006 |
|
|
Tonnes
(000s) |
Zn
(%) |
Pb
(%) |
Cu
(%) |
Ag
g/t |
Au
g/t |
Tonnes
(000s) |
Zn
(%) |
Pb
(%) |
Cu
(%) |
Ag
g/t |
Au
g/t |
|
Proven and Probable
Reserves |
5,835 |
5.4 |
0.5 |
1.0 |
45 |
1.3 |
6,134 |
5.7 |
0.5 |
1.0 |
41 |
1.2 |
|
Measured and Indicated Resources |
6,323 |
7.3 |
0.6 |
1.3 |
58 |
1.6 |
7,224 |
7.2 |
0.6 |
1.2 |
55 |
1.7 |
|
Inferred Resources |
3,777 |
7.8 |
0.9 |
1.0 |
90 |
2.2 |
4,431 |
6.9 |
0.8 |
1.0 |
81 |
2.0 |
|
Measured and Indicated Resources include Proven and Probable Reserves. |
|
For the December 31, 2007 mineral reserve estimates, metal prices, including premiums, used to determine economic viability were US$1.12/lb. zinc, C$/US$ exchange rate of 1.09, US$600/oz. gold, US$12.00/oz. silver, US$2.55/lb. copper and US$0.54/lb. lead.
Myra Falls currently operates two underground mines: the H-W mine and the Battle-Gap mine. The H-W mine is accessed by a 716m deep, six-compartment shaft which is linked to the production areas by 14km of ramps and lateral development.
The Battle-Gap mine is linked to the H-W shaft by a 1.8km long drift on the 18 level. The main production method in the H-W mine is sub-level stoping with longhole drilling. Mining in the Battle-Gap zone applies sub-level stoping and drift-and-fill techniques.
|
Year Ended December 31 |
2007 |
2006 |
2005 |
Ore Milled (Tonnes)
Zinc (%)
Copper (%)
Silver (g/t)
Gold (g/t) |
726,460
4.8
1.1
42
1.2 |
714,443
5.5
0.9
48
1.5 |
912,656
6.1
1.2
51
1.8 |
Concentrate Production
Zinc (tonnes)
Zinc Recovery (%)
ZincGrade (%)
Gold Recovery (%)
Gold Grade (g/t)
Copper (tonnes)
Copper Recovery (%)
Copper Grade (%)
Gold Recovery (%)
Gold Grade (%)
Gold (tonnes)
Recovery (%)
Grade (g/t) |
56,978
85.3
52.4
22.5
3.5
27,181
77.9
22.4
41.9
13.9
0.5
3.2
9,400 |
64,902
86.5
51.9
18.5
3.0
20,788
73.0
23.5
28.0
14.4
14.1
11.5
9,489 |
90,129
86.3
53.4
21.0
3.9
32,333
69.6
23.6
20.3
10.4
34.7
18.3
8,741 |
Metal in Concentrates
Zinc (tonnes)
Copper (tonnes)
Silver (ounces)
Gold (ounces) |
29,845
6,086
811,353
18,880 |
33,708
4,885
857,775
20,231 |
48,084
7,640
1,165,056
31,744 |
The Myra Falls concentrator has a rated capacity of 1.4 million tonnes per year and produces zinc and copper/precious metals concentrates.
Concentrate is transported from the property in 38-tonne truck/trailer units 90km to Discovery Terminal, a deep-sea docking facility located in Campbell River. The concentrates are loaded onto barges or ships for smelters in Asia, Europe and North America.