Fosterville overview
suregold Overview
The mine is located in an area with well-developed infrastructure and is accessible by paved
roads. Fosterville’s ore is processed at the Fosterville mill which has a capacity of 2,275 tonnes
per day.
With the completion in February 2022 of the merger between Agnico Eagle and Kirkland Lake
Gold, the Fosterville mine ranks as the Company’s lowest cost operation with total cash costs
anticipated to be US$457 per ounce gold in 2023 on production of 305,000 ounces of gold.
Gold was first discovered in the Fosterville area in 1894 with mining activity continuing until 1903.
Aside from a minor tailings retreatment in the 1930s, the field lay dormant until 1988. Between
1988 and 2001, a total of 240,000 ounces of gold were poured from heap leaching ore derived
from shallow oxide open pits. The present-day Fosterville mine started underground mining
operations in 2005 and, during its initial years, produced gold from near-surface, low-grade
mineralization.
In 2015, high-grade visible-gold mineralization was intersected at depth, leading to the discovery
of the Eagle Zone and, in 2016, the ultra-high-grade Swan Zone. The discovery of these zones,
particularly Swan, significantly improved mine's overall mineral reserve grade, production profile
and unit-cost performance. In 2016, exploration work found similar visible-gold mineralization in
the Harrier zone. Additional exploration progress in early 2017 resulted in a new mineral reserve
and mineral resource estimate for the operation being released in June 2017 that more than
doubled underground mineral reserves.
With continued exploration success over the remainder of 2017, another mineral reserve and
mineral resource estimate was released in December 2017 that saw mineral reserves rise
another 65% from the June 2017 estimate. Continued drilling in the Lower Phoenix system during
2018 resulted in another significant increase in the Fosterville mine mineral reserves to 2.72
million ounces at an average grade of 31.0 g/t gold.
As of December 31, 2022 at the Fosterville mine, proven mineral reserves were 453,000 ounces
of gold (608,000 tonnes grading 23.19 g/t gold) and probable mineral reserves were 1.2 million
ounces of gold (6.0 million tonnes grading 6.39 g/t gold). Measured mineral resources totalled
125,000 ounces of gold (1.1 million tonnes grading 3.67 g/t gold), indicated mineral resources
totalled 1.6 million ounces of gold (9.7 million tonnes grading 5.18 g/t gold, and inferred mineral
resources totalled 1.2 million ounces of gold (5.6 million tonnes grading 6.53 g/t gold).
The above mineral reserves and mineral resources include the Robbins Hill deposit, a new gold
system identified approximately 4.0 km north of the existing Fosterville mine.
Geology and Mineralization
The Fosterville Goldfield is located within the Bendigo Structural Zone in the Lachlan Fold Belt.
The deposit is hosted by an interbedded turbidite sequence of sandstones, siltstones and shales.
This sequence has been metamorphosed to sub-greenschist facies and folded into a set of
upright, open to closed folds.
Mineralization at Fosterville is controlled by late brittle faulting. These faults are generally steeply
west-dipping reverse faults with a series of moderately west-dipping reverse splay faults formed
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in the footwall of the main fault. There are also moderately east-dipping faults which have
become more significant footwall to the anticlinal offsets along the west dipping faults. Primary
gold mineralization occurs as disseminated arsenopyrite and pyrite forming as a selvage to veins
in a quartz-carbonate veinlet stockwork. The mineralization is structurally controlled with high-
grade zones localized by the geometric relationship between bedding and faulting. Mineralized
shoots are typically 4 to 15 metres thick, 50 to 150 metres up/down dip and 300 to 1,500 metres
down plunge, and have average grades of 5 to 10 g/t gold, with individual assays up to 60 g/t
gold.
Primary gold at Fosterville also occurs as visible gold that variably overprints sulphide
mineralization and is found as disseminated fine specks of gold within host quartz veins. The
visible gold is spatially associated with antimony mineralization in the form of stibnite that occurs
with quartz and varies from replacement and infill of earlier quartz-carbonate stockwork veins, to
massive stibnite-only veins of up to 0.5 metres in width. The stibnite-quartz event occurs in
favourable structural locations, such as the Phoenix, Eagle and Lower Phoenix structures.
The occurrence of visible gold is becoming increasingly significant at depth and is observed more
frequently below approximately 800 metres depth, down-plunge within the Lower Phoenix and
Harrier gold systems.
In the Lower Phoenix system, the high-grade Eagle Zone is 0.5 to 6 metres in width, 50 to 80
metres in dip length and has a down-plunge extent of 700 metres while the Swan Zone —
currently the highest-grade mineralized zone at Fosterville — is 2 to 5 metres in width, dips west
and is presently defined over a 275-metre strike and a 200-metre vertical extent. The Eagle and
Swan zones remain open down-plunge for potential mineral-resource expansion
