The Silver King Project
Silver King
Silver King is a historic high-grade silver, copper, and base metals producer in Arizona, uniquely positioned within the Resolution Copper claim block. With a history of exceptional grades and no modern exploration, it presents significant upside potential for resource expansion and critical mineral discovery, including antimony. An initial 1,000-meter drill program is planned to target high-grade zones at multiple depths
Location & Accessibility
Location of Silver King Project and the surrounding mines in Arizona.
The Silver King Property is a 125-hectare project located near Superior, Arizona. It is strategically positioned only 3 km from the main shaft of the Resolution Copper project, a joint venture between BHP and Rio Tinto, recognized as the world’s largest unmined copper deposit. The Silver King land position is unique as it sits entirely within Resolution Copper’s large claim block.
Aerial view of the Silver King mine area with approximate land boundaries. The Silver King acquisition, including the two patented claims, is shown in orange.
Geological Setting & Mineralization
The Silver King ore body is described as a steeply west-dipping pipelike stockwork and breccia zone, hosted within quartz diorite intrusion and surrounded by Precambrian basement, Paleozoic limestone, and Tertiary cover rocks. Historical mining accessed the deposit on eight levels to a depth of about 300 meters below a surface glory hole.
Geologic map of the Silver King mine area showing quartz diorite intrusion (orange) that hosts mineralization. Surrounding rocks are Precambrian basement, Paleozoic limestone, and Tertiary cover.
The high-grade mineralization was initially mined at the surface, with lower-grade material present in the surrounding rocks. Minerals of importance identified below the oxidized zone include stromeyerite (silver copper sulfide), Ag-bearing tetrahedrite (freibergite – a silver copper antimony sulfide), acanthite, and native silver, along with galena and sphalerite. The presence of freibergite specifically indicates a strong potential for antimony, a critical mineral with growing strategic demand. Records also suggest that much of the upper portion of the body was not historically mined due to variations in mineralogy.
Historic Production
Discovered in 1875, the Silver King mine became one of Arizona’s most important historical producers.
● Initial Production (1875-1889): Produced nearly 6 million ounces of silver at average head grades ranging from 61 oz/ton to 21 oz/ton, with significant copper, lead, and zinc values. Near-surface production in one area was reported to measure 10,000 ounces per ton silver.
● Second Production Period (1918-1928): Produced over 230,999 ounces of silver with an average head grade of 18.7 oz/ton.
● Post-1928: No significant production has occurred since 1928.
● Late 1990s Small-Scale Production: The main shaft was dewatered and rehabilitated, allowing access to the uppermost levels for small-scale production. Samples taken during this period demonstrate that high-grade mineralization remains, with assays as high as 644 oz/t Ag (18,250 g/t Ag) and 0.53 oz/t Au (15 g/t Au). Surface samples also yielded 49-124 g/t Ag.
Assay values from the 114-foot level of the Silver King from small-scale production in the late 1990s to 2000.
Sample | Easting | Northing | Type | Au oz/t | Ag oz/t |
181 | 114 level |
| Selected | 0.12 | 401 |
199 | 114 level |
| Selected | 0.26 | 430 |
255 | 114 level mill run |
| Selected | 0.53 | 644 |
Exploration
Despite its significant historical production, the Silver King deposit has never been explored systematically with modern techniques. Only limited, widely spaced shallow drilling was completed by Magma Copper in the 1970s.
Prismo Metals plans an immediate Phase I exploration program:
- Drilling: A 1,000-meter diamond or RC drilling program is planned to test the main pipelike body at four elevations and laterally.
- Dewatering & Sampling: The shaft will be dewatered to the 256-foot level, which was rehabilitated in the late 1990s, to obtain a bulk sample for metallurgical testing. Submersible pumps are in place for dewatering.
- Mapping & Sampling: Detailed mapping and sampling will be conducted at surface exposures and in accessible underground workings, including other nearby mineral occurrences referenced in historic reports, such as the Black Diamond breccia.
Latest News Releases
- July 18, 2025 – Prismo Metals Announces Closing of Upsized Private Placement Silver King Exploration to Begin in July.
- July 3, 2025 – Prismo Metals Options Two High-Grade Silver-Gold Mines in the Arizona Copper Belt – Immediate Exploration Planned.