Greyhawk Mine is a decommissioned underground

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

mine located in

Faraday Michael Faraday (; 22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. His main discoveries include the principles underlying electromagnetic induction, ...

Township near

Bancroft, Ontario Bancroft () is a town located on the York River in Hastings County in the Canadian province of Ontario. It was first settled in the 1850s by United Empire Loyalists and Irish immigrants. From the mid-1950s to about 1982, mining was the primar ...

. It operated from 1954 to 1959 and from 1976 to 1982. The mine produced 80,247 tons of uranium ore, of which 0.069% was U₃O₈ worth $834,899. Aside from uranium, the mine has produced some of the world's best samples of Kainosite-(Y).

Uranium discovery - 1922 to 1954

Uranium was first discovered in the nearby area of

Cardiff Cardiff (; cy, Caerdydd ) is the capital and largest city of Wales. It forms a principal area, officially known as the City and County of Cardiff ( cy, Dinas a Sir Caerdydd, links=no), and the city is the eleventh-largest in the United Kingd ...

in 1922 by W. M. Richardson. Between 1953 and 1956, one hundred area prospects were opened, including one by one which developed into Greyhawk Mine.

Mine operations - 1954 to 1982

In 1954, Goldhawk Porcupine Mines Limited (who later became Goldhawk Uranium Mines Limited) undertook geology surveys, drilling to 450 feet deep. During 1955 and 1956 Greyhawk Uranium Mines Limited sunk a vertical shaft to 361 feet creating three levels at depths of 110 feet, 211 feet, and 333 feet. They then drilled 114 holes (totalling 42,299 feet of drilling). By late 1956, there was 430 feet of underground cross-cuts, 1,606 feet of drifting, and 512 feet of raising, all at the first level. Underground drilling totalled 10,542 feet over 76 holes. In 1958, the shaft was lowered further, to a new depth of 402 feet, from where lower levels were established. The ore was processed at the nearby Faraday mill on the

Faraday Mine Madawaska Mine (previously known as Faraday Mine) is a decommissioned underground uranium mine in Faraday, near the town of Bancroft, Ontario, which produced 9 million pounds (4,082 tonnes) of U3O8 concentrate, at an average ore grade of 0.1074 ...

site. Mining operations stopped in 1959. Faraday Uranium Mines Limited purchased the site from Goldhawk Uranium Mines Limited in 1962. Madawaska Mines Limited was formed in 1975 and purchased the site, as well as the nearby

, restarting mining operations in 1976 until 1982.

Production

Over it's two periods of operations, the mine produced 80,247 tons of uranium ore, of which 0.069% was U₃O₈ worth $834,899. In addition to uranium, the mine produced some of the world's best samples of Kainosite-(Y).

Incidents

* Rosaire Adrienne Lamirande, a 36 year old machine operator, was killed by falling rock in 1958.

Post mining

1978 and 1980 studies found that the natural weathering of the

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

and

gabbro Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is che ...

rocks left on site has caused uranium leaching into the

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...

at concentrations ranging between 1.2 and 380 parts per billion, with higher concentrations measured deeper in the water table and in sediments. 200,000 tons of ore, averaging 0.065% U₃O₈, remain in the ground. As processing was done offsite, there are no tailings on site, therefore unlike the other nearby former uranium mines ( Faraday/Madawaka Mine,

Bicroft Mine Bicroft Mine is a decommissioned underground uranium mine, located near Bancroft, Ontario, Canada. It is one of fourteen former uranium mines in Ontario that is monitored by the Canadian Nuclear Safety Commission, and one of twenty in Canada. ...

, and

Dyno Mine Dyno Mine is a decommissioned underground uranium mine located at Cardiff, near Farrel Lake, approximately 30km southwest of Bancroft, Ontario. It operated from 1958 to 1960. Uranium discovery - 1922 to 1956 Uranium was first discovered in th ...

), the

Canadian Nuclear Safety Commission The Canadian Nuclear Safety Commission (CNSC; french: Commission Canadienne de sûreté nucléaire) is the federal regulator of nuclear power and materials in Canada. Mandate and history Canadian Nuclear Safety Commission was established under t ...

does not regulate the site. The mine was owned by

Ovintiv Ovintiv Inc. is a hydrocarbon exploration and production company organized in Delaware and headquartered in Denver, United States. It was founded and headquartered in Calgary, Alberta, under its previous name Encana. It was the largest energy co ...

subsidiary

EWL Management Limited The successor of multiple historical Canadian mining and energy companies, EWL Management Limited was an Alberta based corporation that owned five decommissioned mines in Ontario, including three former uranium mines. The company was one of seven ...

, which merged into Ovintiv in February 2022.

References