Prismo Metals (WKN A2QEGD / CSE PRIZ) has completed its Phase I diamond drilling program at the Silver King project in the Pioneer Mining District near Superior, Arizona, and has significantly sharpened the geological picture of the deposit. The company completed eight drill holes totaling 1,272 meters of core drilling. Seven holes were designed to test the upper portions of the historically mined, pipe-shaped mineralized body, while one deep hole specifically investigated the continuation below the former mine workings. And the tests were successful!
For Prismo, this is particularly relevant because all drill holes intersected the targeted quartz-vein and stockwork system within the pipe-shaped structure. According to the company, this confirms both the historical underground data and its own 3D model of the old mine workings. At the same time, the drilling provided indications that the upper parts of the deposit were apparently not mined as extensively as historical reports had suggested.
Silver King is not an unknown name in Arizona. Discovered in 1875, the mine was the state’s first silver mine and was among the more significant historical producers. According to historical information, nearly 6 million ounces of silver were produced there at grades of up to 61 ounces (!) per ton. (However, these are historical figures that do not comply with today’s Canadian NI 43-101 standard.) The project is also only 3.4 kilometers from the main shaft of the Resolution Copper project, a joint venture between Rio Tinto and BHP, which includes an estimated copper resource of 1.787 billion tonnes averaging 1.5% copper.
Prismo Metals confirms the silver zone in the upper part of Silver King
The drilling campaign was initially designed to better define the near-surface sections of the known Silver King system. According to Prismo Metals, several drill holes returned broad intervals of classic epithermal quartz-barite veins and stockwork zones with varying sulfide contents. Visual inspections and handheld XRF analyses confirmed silver-bearing minerals such as freibergite, stromeyerite, acanthite and native silver. These were accompanied by bornite, chalcopyrite, sphalerite and galena.
This strengthens the evidence that the historic pipe-shaped orebody continues to host well-developed silver mineralization. In the company’s view, the upper parts of the system display precisely those characteristics typical of high-grade epithermal silver mineralization. In this context, Prismo Metals notes that the initial shallower holes provided enough positive observations to bring forward the deep hole originally planned for Phase II.
This decision proved important for the overall understanding of the project. While the shallow drilling confirmed the established picture of historic silver mining, the deep hole opened up a new perspective on the system. What was a classic silver story could thus develop into a broader polymetallic exploration target, in which silver in the upper zone and copper at depth form a single geological unit.
Deep drill hole changes the picture at Silver King
Particular attention is on drill hole SK-26-07, which was drilled to 1,600 feet, or 488 meters. This hole intersected quartz veining and stockwork below the historically deepest level of the mine, which was at around 700 to 800 feet. In this interval, Prismo Metals encountered a previously unrecognized quartz monzonite intrusion with abundant finely disseminated pyrite, locally strong potassic alteration, and irregular sulfide blebs and veinlets with scattered chalcopyrite and pyrrhotite.
These features in particular differ markedly from the predominantly epithermal quartz-sericite alteration around the historic Silver King orebody. In the company’s assessment, they instead indicate proximity to a porphyry copper system. The observed potassic alteration is expressed, among other things, in secondary biotite in narrow quartz veins and as replacement of hornblende phenocrysts, in pink K-feldspar along vitreous quartz veins, as well as in an increasing frequency of pyrite blebs and thin pyrite veinlets that locally also carry chalcopyrite.
For Prismo, this development is significant because it suggests vertical zoning: high-grade silver mineralization in the upper zone, and at greater depth, features of a possible porphyry copper system. The company draws parallels to regional transitions from silver to copper systems, which are also historically known in the surrounding area. The location in close proximity to the Resolution Copper project and adjacent to its claim block increases the significance of these observations in a regional context.
Silver King moves to the forefront for Prismo Metals as a polymetallic target
The Silver King project area lies in volcanic and intrusive rocks of Laramide age. Within an erosional window, several intrusive phases are exposed there, including syenite, quartz syenite, quartz monzonite, granodiorite and hornblende andesite. Numerous historic mine workings in this area support Prismo Metals’ interpretation that Silver King could be part of a telescoped system: deeper, higher-temperature porphyry-style alteration with a potentially copper-rich hypogene core, overlain by later-formed epithermal silver and base-metal veins.
Before the start of Phase II, Prismo Metals now intends to establish additional data foundations. Planned work includes downhole geophysics, petrographic thin-section analyses of key rock types, multi-element geochemistry, and mapping of structures and alteration patterns in the mineralized area. This will be complemented by a detailed investigation of the Crown Porphyry stockwork north of the Black Diamond skarn replacement body east of the historic Silver King mine workings. On this basis, more precise targets are to be defined for deeper step-out drilling to test the inferred silver-copper system at depth.
In parallel, Prismo Metals has appointed Dr. Linus Keating as Special Advisor. He brings more than four decades of global exploration experience, including 14 years with Rio Tinto and Kennecott. His work ranged from Nevada to Argentina, including early work that later led to drilling at the Altar porphyry copper deposit. At Silver King, he is now expected to support the company in further refining the geological model and planning the next drilling phase.
Samples from five drill holes have already been submitted to an independent laboratory. Additional samples from drill holes SK-26-06 to SK-26-08 are expected to follow later this week. Prismo Metals expects the final results in May 2026. Until then, it is already becoming clear that Silver King is gaining importance for the company not only as a historic silver mine, but increasingly as a modern polymetallic exploration target.
