The Kirkland Lake mining camp is located in the west portion of the Archean Abitibi greenstone belt of the Abitibi Subprovince. The Timiskaming Group of rocks is the main feature of the Kirkland Lake area. It is up to 10,500 feet thick and extends for about 40 miles from Kenogami Lake in the west to the Quebec border in the east. In the Kirkland Lake area, the Timiskaming is predominantly comprised of conglomerates, greywackes, trachytic lava flows and alkalic tuffs. The Timiskaming trends N650 E and dips steeply south in the Kirkland Lake area. The Timiskaming sediments are intruded by strike parallel to shallow discordant augite syenite, feldspar porphyry and minor late diabase dykes. The intrusives tend to be steeper dipping than the sediments. Mineralization is known to occur in both the sediments and intrusives, though the syenites are the preferential host.
The Kirkland Lake Main Break system has produced over a span of 86 years, 24 million troy ounces of gold, representing some 15% of total Canadian gold production as of 1999. Mining took place along a strike length of 21,000 feet and to a depth of 8,100 feet. Some of the greatest gold mines in Canada were located along the Main Break including the Sylvanite, Wright Hargreaves, Lakeshore, Teck Hughes, Kirkland Minerals and Macassa. The average historic grade of this production is 0.48 ounces of gold per ton. At both the Wright Hargreaves and Lakeshore mines, high grade gold mineralization is still present at the 8,100 foot level.
The most important structural controls in the Kirkland Lake Camp (until the discovery of the South Mine Complex) are the major east-west breaks and the branching fault systems associated with them. The breaks represent re-activated fault systems with ore shoots having been formed synchronously with early displacement with the most recent movement having displaced the ore. Ore shoots may occur both on the hanging and footwall side of the Break planes.
The Main Break has been traced east as far as the Toburn Mine and west onto the Macassa mine as far as Macassa #2 shaft.. The Main Break is interpreted to be a post ore structure, one to twenty feet wide marked by a zone of mylonitized and sometimes brecciated wall rock, chlorite schist and mud or gouge. It is a thrust or reverse fault with an estimated displacement of 1,500 feet on the overlying sediments. The strike of the Break averages N 650 E and dips 800 to the south, gradually flattening in dip to 500 degrees at depth.
In 1955 a new major break was discovered on the Macassa property termed the `04 Break. Located 400 feet north of the Main Break, the `04 Break has been the most important ore-related structure at Macassa since the 1980’s. The Main and `04 Breaks are connected through a series of linking structures in the vicinity of Macassa #2 shaft which include the S and R Breaks. The 04 Break is the host for most of the ore at Macassa, is a thrust or reverse fault with at N 650 E strike and a 720 south dip. Ore is located along this and subordinate splays as quartz veins. Gold is usually found with minor pyrite and sometimes associated with molybdenite and/or tellurides. The presence of tellurides usually indicates high grade ore.
As of December 31st, 2011, current reserves and resources in the Main, '04 and related structures, not including the South Mine Complex include:*
| Category | Tons | Grade (opt) | Ounces |
|---|---|---|---|
| Proven: | 1,040,000 | 0.40 | 420,000 |
| Probable: | 571,000 | 0.42 | 238,000 |
| Measured Resource | 1,055,000 | 0.40 | 420,000 |
| Indicated Resource | 1,136,000 | 0.37 | 422,000 |
| Inferred Resource | 970,000 | 0.35 | 341,000 |
*See Kirkland Lake news release dated May 30th, 2012, a copy of which has been filed on SEDAR for further particulars. The contents of the above reserve and resource statements have been verified and approved by the Company's Chief Exploration Geologist, Stewart Carmichael, P.Geo, a “qualified person” for the purpose of National Instrument 43-101, Standards of Disclosure for Mineral projects.
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