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Relief Canyon mine, US

23rd July 2021

By: Sheila Barradas

Creamer Media Research Coordinator & Senior Deputy Editor

     

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Name: Relief Canyon mine.

Location:  Pershing County, Nevada, in the US.

Mine Owner/s: Americas Gold and Silver.

Brief Description: Relief Canyon comprises an openpit mine and heap-leach processing facility.

Brief History: Gold was not identified in the area until 1979, when a regional precious metals prospecting programme conducted by the Duval Corporation generated anomalies in the area. Drilling in 1981 and 1982 confirmed the presence of a low-grade zone of gold.

Duval sold the property to Lacana Mining in 1982. After drilling 204 reverse circulation holes and undertaking pilot-scale heap-leach testwork, Lacana opened the openpit Relief Canyon mine in September 1984. Lacana closed the mine in October 1985 owing to poor gold recoveries.

Pegasus Gold Corp acquired the property from Lacana in 1986 and reopened the mine in 1987. Mining ceased in 1989.

JD Welsh and Associates of Reno acquired the property from Pegasus in September 1993 and reportedly produced several thousand ounces of gold by continuing to rinse the existing heaps. Firstgold Corporation (formerly Newgold), acquired the Relief Canyon property from Welsh in January 1995.

Following some drilling on the property in 1997 the mine was idle until 2003. Subsequent exploration by Firstgold focused on the potential for mineralisation between the existing pits and to the north and north-west.

Firstgold redeveloped and rebuilt the Relief Canyon heap-leach processing facilities in 2007 and 2008. The company attempted to reprocess some of the previously leached material in late 2008 and early 2009, but shut the project down within a few months. Firstgold filed for bankruptcy protection in January 2010.

Platinum Long Term Growth acquired the Relief Canyon assets, from whom Americas Gold and Silver, then Pershing Gold, acquired the Relief Canyon mine in August 2011.

Commercial production was declared at Relief Canyon on January 11, 2021.

Primary Metals/Minerals: Gold.

Secondary Metals/Minerals: Silver.

Geology/Mineralisation: The Relief Canyon property is located on the western flank of the southern Humboldt Range, one of the generally north-trending, fault-bounded ranges of the Basin and Range physiographic province. The oldest rocks exposed in the range are mafic and silicic volcanic rocks of the arc-related Lower Triassic Koipato Group, which are overlain by marine carbonate rocks of the middle to late Triassic Star Peak Group.

The Cane Spring Formation lies at the top of the Star Peak Group and hosts the gold mineralisation at Relief Canyon.

Gold mineralisation occurs in the foliated carbonate package and the thick-bedded limestone unit and is spatially correlated with the contacts of the gabbro intrusions.

Mineralisation at the Relief Canyon mine is found in three mineral zones, which are structurally controlled and characterised by distinctive host rocks. From structurally lowest to highest, the zones are the Jasperoid Zone, the Lower Zone, and the Main Zone. The Main Zone hosts the bulk of the current and historical gold resources at Relief Canyon, while the Lower and Jasperoid zones are newly discovered mineral zones encountered below the Main Zone in the North Target area.

Quartzillite/fluorite/kaolinite alteration is associated with gold mineralisation in all three mineral zones.

Reserves: Total proven and probable reserves as at June 30, 2020, were estimated at 24.81-million tonnes grading 0.77 g/t gold and 2 g/t silver.

Resources: Total measured and indicated resources as at June 30, 2020, were estimated at 2.92-million tonnes grading 0.62 g/t gold and 1.1 g/t silver. Inferred resources were estimated at 3.08-million tonnes grading 0.27 g/t gold.

Mining Method: Openpit methods, followed by heap leaching.

Major Infrastructure and Equipment: Significant infrastructure exists at the Relief Canyon site from previous operations. Existing installations include site access and haul roads; an adsorption, desorption, recovery circuit; process solution ponds; a heap-leach pad, waste rock facilities, site buildings, electrical power supply, water wells, and fencing around the process facilities.

The existing gold recovery plant has the capacity to handle an estimated 11 000 ℓ of gold-bearing solution. The leach pad is permitted to hold 21-million tonnes and can be readily expanded. A crushing and conveying system will be built to allow for ore placement of more than six-million tonnes a year. 

Prospects: Americas Gold and Silver's landholdings cover about 11 000 ha, which includes the Relief Canyon mine and lands surrounding the mine in all directions. This land package provides the company with the opportunity to expand the Relief Canyon deposit and to explore and make new discoveries on nearby lands. 

Contact Details:
Americas Gold and Silver
Tel +1 416 848 9503
Email info@americas-gold.com

Sources:
Americas Gold and Silver. website https://www.americas-gold.com/ (Accessed: July 8, 2021).
Americas Gold and Silver.. Relief Canyon Technical report and feasibility study (July 6, 2018).

 

Edited by Creamer Media Reporter

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