- SMDI #
- 0113
- Current Showing Name
- Birch Lake Mine
- Historical Showing Names
- Birch Lake Mine
- Company Name
- Project Name
- UTM Easting (NAD83 Z13)
- 691341.1700
- UTM Northing (NAD83 Z13)
- 6061123.5700
- NTS Sheet
- 063L09
- TRM (Township-Range-Meridian)
- 65-01-2
- Primary Commodities
- Copper
- Associated Commodities
- Cadmium, Gold, Selenium, Silver, Tellurium, Zinc
- Discovery Type
- Status
- Deposit: Post-Production
- Geological Details
- The Birch Lake orebody that comprises the showing is located on the east side of a large island near the south end of Birch Lake.
The Birch Lake deposit is hosted within northerly trending, sub-vertical arc-type Amisk Group Ruth Lake Assemblage volcanics that have been deformed by several relatively tight north trending folds. The volcanics,which have been intruded by a series of quartz-feldspar porphyry and rhyolite porphyry sills and dykes. The metavolcanics have been subjected to greenschist facies metamorphism and are highly altered along the zone of shearing which hosts the deposit.
The original surface showing, which was discovered by Joe Brain, consists of a locally malachite stained chlorite schist which is mineralized with carbonate, disseminated pyrite-pyrrhotite, and a few stringers of chalcopyrite. The mineralization occurs within a major 005° to 017°/70 to 75°NW trending shear zone which cuts a series of andesitic to basaltic metavolcanics. This major shear zone extends beneath Birch Lake and south through Ruth and Table lakes. Ground EM surveys outlined three conductive bodies along this major fault.
The "Main Shear Zone" body underlies the north end of the island and the adjacent waters of Birch Lake west of the island. Drilling outlined several roughly tabular shaped bodies of chalcopyrite-pyrrhotite-pyrite-magnetite-sphalerite mineralization which are an average 6 ft (1.83 m) wide by 150 to 300 ft (45.7 to 91.4 m) long. The mineralization occurs as disseminations and as small lenses and veinlets which are less than 1 inch to several feet wide. In places, the ore consists of 30% to 40% chalcopyrite. This body was mined as the Birch Lake Mine.
The "South Pyrite Zone" is located 500 m (1640.4 ft) south of Birch Lake. Drilling over a 1200 ft (365.8 m) strike length exposed small irregular masses and veinlets of pyrite-pyrrhotite with minor chalcopyrite and sphalerite in a steeply dipping band of sheared agglomerate. The host agglomerate consists of up to 3 inch (7.6 cm) in diameter rounded and angular white fragments in a dark grey matrix which has been partially replaced by the sulphide mineralization. Locally, the rock is almost completely sulphide replaced to form near solid sulphide. This body forms the mineralization further described by SMDI 0163.
The " North Zone" body is located 1371.6 m (4500 ft) north of the "Main Shear Zone" body under a small lake which is just opposite the west narrows of Birch Lake. The description of the mineralization is similar to that at the "Main Shear Zone" but the ore is more consistant and over greater widths. This body was mined as the Flexar Mine or SMDI 0117.
The Birch Lake deposit host rock is described as a thin unit of rhyolite tuff-agglomerate. The footwall rocks are a 250 to 300 m (656.2 to 984.3 ft) thick sequence of pillowed basalts and the hanging wall rocks consist of andesite tuff. The host volcanics have been altered along the host shear. Epidote, brochantite, atacamite, and develline alteration products have been reported in the host rocks up to 2 ft (0.6 m) out from the orebody.
The rocks in the mine area have been variably sheared and altered to chlorite schist. Mineralization is concentrated along these north trending shears that run between the Birch Lake Mine and the Flexar Mine (SMDI. 0117). The ore-waste contact on the hanging and footwalls is quite sharp.
The deposit consists of a number of tabular bodies ore lenses that contain semi-massive to massive sulphide that includes chalcopyrite, pyrite, pyrrhotite, and lesser magnetite and sphalerite. The orebody varies from 150 to 200 ft (45.7 to 61.1 m) in length and has an average width of 6 ft (1.8 m).
Mining began in 1957 and continued until the ore was exhausted in 1960. Exploration drilling along the several north trending shears that extend from the Birch Lake Mine to the Flexar Mine intersected values up to 0.49% Cu over 13 ft (4 m). Locally, up to 2% Cu over short widths was intersected.
- Geological Domain
- Flin Flon
- Host Rocks
- Host Minerals
- Indicators
- Exploration History
- 8/3/1988 The Birch Lake deposit was discovered by J. Brain in 1949 and was optioned to Hudson Bay Mining and Smelting Co. Ltd. the same year.
The original deposit was prospected and diamond drilled during 1951 to 1952 at which time the orebody was outlined. 63 delineation holes, totalling 12,191 m were completed.
Development work during 1952 to 1956 consisted of 6927 ft (2111.3 m) of development drilling and the sinking of a 1642 ft (500.5 m) 3-compartment shaft. Lateral drifting commenced on six levels.
Mining began in 1957 and continued until the ore was exhausted in 1960. During this period, 300,819 short tons of ore grading 6.21% Cu were mined. The ore was trucked to the nearby Coronation Minesite and hauled from there to the Flin Flon smelter by rail. All mine buildings have been dismantled and removed.
In 1982, Hudson Bay Exploration completed ground EM and magnetic surveys between Birch and Ruth Lakes.
In 1987, Hudson Bay Exploration completed ground EM and magnetic surveys and drilled 1 hole in the vicinity of Birch Lake Mine.
In 1990, Hudson Bay cut a new grid immediately west of the mine site on the west shore of Brain (Birch) Lake and completed ground VLF-EM and magnetic surveys. In 1991, Hudson Bay Exploration completed drill holes B-85 to -88 on this grid (AF 63L09-0381). Drill hole B-85 to -87 encountered a horizon (under the channel immediately west of the mine site) with disseminated sub-economic py-po-cpy mineralization which returned minor copper values. Drill hole B-88, which was spudded to test the mine horizon below the workings, encountered minor Cu-Zn values in this horizon.
In 1991, Hudson Bay completed drill holes B-89 and B-89W1 to test the down-plunge aspect of the mined out Birch Lake Deposit below the current workings (AF 63L09-0385). Drill hole B-89 interstected up to 6% bleb type chalcopyrite from 1431.9 to 1432.8 ft.
On 8 October 2004, it was announced that Ontzinc Corporation had purchased Hudson Bay Mining and Smelting from Anglo American International SA and that it was renamed Hudson Bay International Minerals Corporation.
- Production History
- Production Period: 1957-01-01 to 1960-01-01
307,265.00 tons
The sinking of a 502 m three compartment shaft and initial underground development work was completed between 1952 and 1956. Mining commenced in 1957 and continued until ore was exhausted in 1960. The ore was trucked to the Coronation Mine then hauled by railway to the Flin Flon smelter.
The Birch Lake Mine produced 307,265 tons of ore that graded 6.17% Cu, 0.003 oz/ton Au, and 0.12 oz/ton Ag. The deposit yielded a total of 33,750,845 lbs Cu, 40,560 lbs Sn, 74 lbs Cd, 43,235 lbs Se and Te, 813 ounces Au, and 30,780 ounces Ag.
Summary:
- Cadmium: 74.00 lb
- Copper: 33,750,845.00 lb @ 6.17 %
- Gold: 813.00 oz @ 0.00 oz/ton
- Selenium: 21,617.00 lb
- Silver: 30,780.00 oz @ 0.12 oz/ton
- Tellurium: 21,617.00 lb
- Tin: 40,560.00 lb
- Reserves and/or Resources