Looking West at the Homestake Mine Model

  • 125 years of operation, discovered in 1876, and closed in 2001 due to low gold price; it did not run out of gold mineralization
  • >42M oz Au production from 152 Mt @ 8.4 g/t Au
  • Open below 8500-foot level
  • Largest iron formation hosted gold deposit in the world

7430-ft. Level: Quartz vein in Homestake Formation with arsenopyrite and pyrrhotite

Homestake BIF Gold Ore Ledges

  • 11 gold ore ledges were mined at Homestake, averaging 8.38 g/t Au.
  • The Main Ledge was 74m tonnes (19.07m oz. Au produced)
  • 9 Ledge was 36m tonnes (9.50m oz. Au produced)
Ledge
g/t Au
Mt
Au (M oz)
Caledonia Ledge
7.43
4.90
1.06
Main Ledge
8.73
74.00
19.07
7 Ledge
7.31
4.80
2.00
9 Ledge
9.05
36.00
9.5
11 Ledge
7.87
7.10
1.62
13 Ledge
8.71
2.20
0.56
15 Ledge (est.)
9.10
3.75
1.00
17 Ledge
6.94
7.00
1.42
19 Ledge
7.03
2.30
0.47
21 Ledge
8.34
9.40
3.50
23 Ledge
-
-
0.52
Summary
Weighted average g/t Au - 8.38 g/t
Total Metric Tonnes (Millions) 151.45 M Oz Total Au
As of 1992: 36.28 M oz. produced; 4.45 M oz. Reserves (23 Mt @ 6 g/t)

The district-scale potential for BIF-hosted gold deposits is the attribute that places this deposit type on the radar of both juniors explorers and major producers. Like VMS deposits, they are often found in clusters. This characteristic is highly attractive to major gold companies looking for new deposits that can be developed into mines with longevity.

Banded iron formation-hosted gold deposits are attractive targets thanks to their potential for large, district-scale gold mining. Although large, low-sulfidation epithermal gold and sediment-hosted Carlin-type deposits get the most attention from today’s gold mining news, banded iron formation-hosted gold deposits rank highly amongst the world’s most attractive exploration targets. While not as common as other greenstone-hosted orogenic gold deposits, gold-bearing BIFs occur in Archean to Proterozoic-age cratonic greenstone belts all around the world. The best examples of BIF-hosted gold deposits are found in Canada, the United States, Western Australia, Brazil, Zimbabwe and India.

Located in the eastern margin of the Wyoming Archean craton in South Dakota, the Homestake mine was North America’s largest and deepest gold mine prior to its closure in 2002. During its 125 year mine life, Homestake reportedly produced >42 million ounces of gold and was the second largest gold producer in the United States after the Carlin district in Nevada. One of Canada’s largest producing gold mines is a BIF-hosted gold deposit located in the province of Ontario. Newmont Goldcorp’s 4,000 tonne per day operation at the Musselwhite mine went into commercial production in 1997 and since then has produced more than 4 million ounces of gold with gold recoveries of 96 percent. Today, Musselwhite has proven and probable gold reserves of 1.85 million gold ounces, measured and indicated resources of 310,000 gold ounces as well as inferred resources of 1.17 million gold ounces.