Silver Crater Mine

{{Infobox mine|name=Silver Crater Mine|pushpin_map=CAN ON Hastings#Canada Southern Ontario#Ontario|pushpin_label=Silver Crater Mine|coordinates={{coord|45|02|N|78|01|W|region:CA-ON|format=dms|display=inline,title}}|pushpin_map_caption=Location near Cardiff, Ontario|subdivision_type=Province|closing year=1955|owner=Silver Crater Mines (International Cobalt and Silver Mining Company subsidiary)}}{{Short description|Ontario decommissioned mine}}

Silver Crater Mine, previously known as the Basin Deposit,{{cite journal |last1=Joyce |first1=David K. |title=Calcite Vein-Dikes of the Grenville Geological Province Ontario, Canada |journal=Rocks & Minerals |date=January 2006 |volume=81 |issue=1 |pages=34–42 |id={{ProQuest|231984951}} |doi=10.3200/RMIN.81.1.34-42 |bibcode=2006RoMin..81...34J |s2cid=129157370 }} is an abandoned mine in Cardiff, Ontario. It has produced some of the world's most notable betafite crystals.

The mine has been worked since the late 19th-century, with industrial mining of mica starting in 1927. Uranium was sought in the 1950s and the mine has been abandoned since 1955.

Location, nomenclature, and geology

Silver Crater mine is located 8 miles west of Bancroft.{{Cite web |title=Silver Crater Mine, Faraday Township, Hastings County, Ontario, Canada |url=https://www.mindat.org/loc-545.html |access-date=2023-02-11 |website=www.mindat.org |archive-date=2023-02-11 |archive-url=https://web.archive.org/web/20230211194354/https://www.mindat.org/loc-545.html |url-status=live }} It was previously known as the Basin Deposit or Basic Occurrence.

The mine is located in the Grenville Province geological area.{{cite journal |last1=Emproto |first1=Christopher |last2=Alvarez |first2=Austin |last3=Anderkin |first3=Christian |last4=Rakovan |first4=John |title=The Crystallinity of Apatite in Contact with Metamict Pyrochlore from the Silver Crater Mine, ON, Canada |journal=Minerals |date=7 March 2020 |volume=10 |issue=3 |pages=244 |doi=10.3390/min10030244 |bibcode=2020Mine...10..244E |doi-access=free }} Mining activity enabled access to crustal carbonatite in a biotite-amphibolite and syenitized gneiss rock, located between an area of granite to the north and marble to the south.

Geologists assess that the minerals found at the mine reached the current location about 1,050 or about 1,150 million years ago.

History and activities

Prospectors have worked the area of the mine since the late 19th-century, seeking mica, phosphate, and feldspar.

S. Orser and D. J. Wilson worked the mine in 1925.{{Cite web |title=Ontario Mineral Inventory Record MDI31E01SE00054: Basin, Silver Crater (Basin) |url=http://www.geologyontario.mndm.gov.on.ca/mndmfiles/mdi/data/records/MDI31E01SE00054.html |access-date=2023-02-11 |website=www.geologyontario.mndm.gov.on.ca |archive-date=2023-02-11 |archive-url=https://web.archive.org/web/20230211194354/http://www.geologyontario.mndm.gov.on.ca/mndmfiles/mdi/data/records/MDI31E01SE00054.html |url-status=live }} In 1927, Bancroft Mining Company started excavations and found a cavity holding albite, fluorite, pyrite, sphene, and apatite crystals on the cavity floor.{{cite book |last1=Gordon |first1=Michael |title=Rockhound: An Experience of the North |date=2015 |publisher=Lulu |isbn=978-1-312-99297-9 }}{{pn|date=February 2023}}{{self-published inline|date=February 2023}} Pits were dug around the mine from which mica crystals as large as four-feet across were harvested until the 1940s. Between the mica formatings, apatite, betafite, and lepidomelane were also found.

Bancroft Mica and Stone Products Mining Syndicate operated the mine from 1947 to 1949 and sold the mica which they extracted from a 30 foot by 65 foot wide open pit.J. Satterly and D. F. Hewitt, [http://www.geologyontario.mndmf.gov.on.ca/mndmfiles/pub/data/imaging/S002/S002.pdf Some Radioactive Mineral Occurrence in the Bancroft Area] {{Webarchive|url=https://web.archive.org/web/20220125021813/http://www.geologyontario.mndmf.gov.on.ca/mndmfiles/pub/data/imaging/S002/S002.pdf |date=2022-01-25 }}, Province on Ontario, 1955

class="wikitable"

|+Bancroft Mica and Stone Products Mining Syndicate

!Year

!Mica Production

1947

|$738

1948

|$7,474

1949

|$7,846

1950

|$10,353

Toronto-based Silver Crater Mines incorporated in 1951, bought the mine in 1953, and operated it from 1953 to 1955, hoping to find uranium, and driving a 70-metre deep adit into the hillside. Silver Crater Mines is a subsidiary of the International Cobalt and Silver Mining Company (incorporated September 19, 1906, Sault Ste. MarieLegislative Assembly of Ontario, [http://www.geologyontario.mndm.gov.on.ca/mndmfiles/pub/data/imaging/ARV16//ARV16.pdf Sixteenth Annual Report of the Bureau of Mines, 1907, Volume XVI, Part 1] {{Webarchive|url=https://web.archive.org/web/20230211205523/http://www.geologyontario.mndm.gov.on.ca/mndmfiles/pub/data/imaging/ARV16//ARV16.pdf |date=2023-02-11 }}, L. K. Cameron (printer) Toronto,) Mining activity ceased in 1955.

Over the years, the mine has produced world class crystals of titanite, apatite, mica, and zircon. Silver Crater Mine is most noted for its unusual betafite crystals, which geologists have yet to sufficiently analyse to understand their geological origins.{{cite journal |last1=Emproto |first1=Christopher |last2=Alvarez |first2=Austin |last3=Anderkin |first3=Christian |last4=Rakovan |first4=John |title=The Crystallinity of Apatite in Contact with Metamict Pyrochlore from the Silver Crater Mine, ON, Canada |journal=Minerals |date=7 March 2020 |volume=10 |issue=3 |pages=244 |doi=10.3390/min10030244 |bibcode=2020Mine...10..244E |doi-access=free }} Betafite crystals from the mine contain 15% to 20% uranium, making them highly radioactive.{{cite journal |last1=Steacy |first1=H R |last2=Rose |first2=E R |last3=Moyd |first3=L |last4=Hogarth |first4=D D |title=Some classic mineral collecting areas in southeastern Ontario |journal=Mineralogical Record |volume=13 |date=1982 |pages=197–213 }}

As recently as 2006, rockhounds visited the mine to collect specimens.