|Years of Operation :||1921 – 1965|
|Ounces of Gold Produced:||4,821,296|
Reproduced with Permission of Kirkland Lake Gold
The Wright-Hargreaves mine is located to the east of Lake Shore in the central portion of the Kirkland Lake camp. It ranks second to Lake Shore in terms of gold production and grade, having produced 4,817,680 ounces of gold at a grade of 0.49 oz/T.
This was the first discovery of gold in the Kirkland Lake camp, made on claim L1830 by W.H. Wright in 1911. In 1913 a shaft (Wright-Hargreaves No.1) was sunk to 85 feet with 110 feet of drifting on the 75-foot level. From 1916-1921 the No.1 shaft was deepened to 400 feet, No.2 Shaft to 320 feet, No.3 Shaft to 425 feet, and a total of 3,900 feet of lateral development took place. In 1921 a mill was constructed and milling started at 175 tons per day.
The mine was developed down to the 8200 foot level, the deepest development in the Kirkland Lake camp. Diamond drilling below the 8200 foot level revealed several high-grade intersections persisting several hundred feet below the level. However, the cost to develop these intersections at such deep levels proved to be too high, and mining was not continued.
The Main Break is the most prominent structure crossing the Wright-Hargreaves property. This structure has been traced, as a consistently strong fault, down to the 8100 foot level, and by diamond drilling below this. A significant amount of ore was mined from this structure, however, most of the tonnage came from the North vein. The North vein branches off the Main Break to the north just to the west of the property boundary with Lake Shore. Stoping on the North vein was extensive to about the 4500 foot level and development was to the 6600 foot level. Below this level, mining was concentrated along ore-bearing fractures of the North vein zone known as the North Heading Vein, North vein, and North D Vein. These veins are typically dipping near 75° south.
Another significant mineralized structure is the South vein-fault which branches off the south side of the Kirkland Lake fault in the western portion of the mine. As with many of the other mines in the camp there are also numerous veins which branch or splay off the main structures and form along tension fractures in the wedge of ground between major faults.
Post-ore faulting at Wright-Hargreaves has been well documented by the mine’s former chief geologist, Harold Hopkins (Thomson, 1950). The Lake Shore fault is the most important post-ore fault in the western portions of the mine. This fault strikes 012- 025° and dips steeply to the east near surface, becomes vertical with depth, then by the 5000 foot level dips to the west. This cross-fault has several important faults branching off the east side including the F and L faults.
A series of four major north-dipping “strike” faults have been numbered 1, 2, 6 and 5. Nos. 1 and 2 faults generally dip at 45°, or less, to the north and displace the Main Break and other vein zones some 150 and 300 feet respectively with reverse movement (hangingwall displaced over the foot wall). The No.6 strike fault has the smallest displacement averaging around 80 feet (again reverse movement), although it has a steeper dip of around 65°. The No.5 strike fault is the most important of these faults and outcrops on surface as the Murdock Creek fault. It can be traced to the east across the Sylvanite and Toburn workings. The fault dips at about 45° north on the Wright-Hargreaves property, but the dip appears to steepen with depth. Displacement on this fault has a maximum of 700 feet (reverse movement) on the Wright-Hargreaves property.
Most of the ore mined at Wright-Hargreaves was found within syenite porphyry with veins north of the Main Break below the 6600 foot level mainly in tuff, greywacke, conglomerate and granite porphyry located in the footwall of the main syenite porphyry plug. The Main Break is located within syenite porphyry throughout the mine. The north veins below the 6600 foot level are much less continuous than veins in the upper levels hosted by syenite porphyry.
The above summary of the history of the Wright-Hargreaves Mine is taken from: STILL, A.C. 2001 Structural setting and controls of gold mineralization at the Macassa Mine, Kirkland Lake, Ontario. Unpublished Masters of Science Thesis, Queens University 151p
Wright-Hargreaves Mine (Past Producer)
Immediately north of Kirkland Lake, in eastern Teck Township. Patented claims L1829- L1831 and L2103. No.4 (main) Shaft in patented claim L1829. Latitude 48.150, Longitude 80.040 . Map reference: ODM 1945-1, Township of Teck.
Almost all of the three claims straddling the “Main Break” is underlain by the main Al goman syenite porphyry stock in the camp. Other rock types encountered underground include Timiskaming conglomerate and greywacke, and Algoman augite syenite. The Kirkland Lake Fault or “Main Break” trends N670E through the centre of the property. It bisects the syenite porphyry stock along its long
axis and, in section, parallels the north contact of the stock. In spite of a southerly dip in part of its downward course, post-ore faults have moved the structure northward, so that at depth the fault is still almost vertically beneath its position on surface. Other ore-bearing structures are found not only in faults that have branched off the “Main Break”, but also in parallel faults and tension fractures. Fissure-filling gold-bearing quartz veins are the most common type of vein; the larger ore bodies on the various faults are of this type. Lodes,
stockworks, and breccia and gash veins are found on subsidiary structures. Numerous post-ore faults occur on the property. The strike and transverse faults have different characteristics. Most of the strike faults dip north, exhibit shearing, and contain late quartz and cal
cite. On the transverse faults, brecciation rather than shearing is more common and gouge is often present; these faults rarely contain quartz and calcite. The north-northeast-trending Lake Shore Fault (a transverse fault), which enters the property in the southwest corner, is the most important post-ore fault. Although much ore was mined from the Kirkland Lake Fault, the most productive structure has been
the North Vein, which branches off the north side of the main fault just west of the Wright-Hargreaves property.
Wright-Hargreaves Mines Limited.
1911: First discovery of gold in the Kirkland Lake camp made in claim L1830 by W.H. Wright.
1913: Shaft (Wright-Hargreaves No.1) to 85 feet with 110 feet of drifting on the 75-foot level and another shaft to 20 feet by “Cartwright interests”
(ODM 1914, Vol.23, pt.1, p.169).
1916-1921: No.1 Shaft deepened to 400 feet, No.2 Shaft to 320 feet, No.3 Shaft to 425 feet, and a total of 3,900 feet of lateral development. In 1921, mill completed and milling started at 175 tons per day. Work by Wright-Hargreaves Mines Limited.
1922-1965: Mine serviced by four shafts and two winzes. The No.4 Shaft, started in 1931, became the main production shaft and eventually reached a depth of 4,089 feet. The No.6 Winze, collared on the 7,050 foot level, took the workings to a depth of 8,100 feet (and continued to 8,222 feet). Under ground development was carried out on 57 levels and, during the life of the mine, totalled: 257,623 feet of drifting, 92,200 feet of crosscutting, and 82,669 feet of raising. Mill capacity reached a maximum of 1,200-1,250 tons per day in 1940. The mill closed in 1957 and from that time until mining operations ceased in 1965, ore was shipped to the Lake Shore mill.
|Year||Gold||Silver||Ore Milled||Recovered Grade|
|(ounces)||(ounces)||(tons)||(ounce of Au per ton)|
CIMM 1948, Structural Geology of Canadian Ore Deposits, Vol.1, p.644-653.
ODM 1923, Vol.32, pt.4, p.39-41.
ODM 1928, Vol.37, pt.2, p.125-133.
ODM 1948, Vol.57, pt.5, p.161-176.
ODM 1964, GC 11, p.41-44.
ODM 1964, MRC3, p.73, 74.
ODM 1965, Vol.75, p63-65.
Gordon, J.B., Lovell, H.L., de Grijs, Jan, and Davie, R.F.
1979: Gold Deposits of Ontario, Part 2: Part of District of Cochrane, Districts of Muskoka, Nipissing, Parry Sound, Sudbury, Timiskaming, and Counties of Southern Ontario; Ontario Geological Survey, Mineral Deposits Circular 18, 253p.