Issue link: http://resourceworld.uberflip.com/i/1239546
A P R I L / M A Y 2 0 2 0 www.resourceworld.com 21 ZEPHYR MINERALS exploring BHT-like project in Colorado by Jennifer S. Getsinger, PhD, PGeo ZEPHYR MINERALS LTD. [ZFR-TSXV: ZPHYF-OTC] is a Canadian mining exploration company with an office in Halifax and its main exploration property (the Dawson-El Plomo-Green Mountain mineralized trend) in west-central Colorado where they are pursuing both a Broken Hill type silver-lead-zinc target and high-grade gold. In a recent telephone interview with Resource World, Zephyr's Will Felderhof sounded excited about the similarities of their Colorado Dawson-El Plomo-Green Mountain Project to Australia's Broken Hill area. Felderhof is the executive Chairman of Zephyr and previously headed up Jascan Resources Inc. which acquired the property from US Borax Ltd. in 1986. Jascan was taken over by Conwest Exploration Ltd. in 1989 which sold the property to Celtic Minerals Ltd. in 1995. Celtic shifted its focus to Voisey's Bay at that time and the property lay idle until 2012 when it was acquired by Zephyr. Being aware of the gold potential of Celtic's Dawson-Green Mountain Project in Colorado from his Jascan days, Zephyr was able to make the acquisition from the financially distressed Celtic in 2012. While half a world apart, Colorado and eastern Australia may have been closer together some 1.7Ga (1,700 million years ago). On a tectonic reconstruction map of Paleoproterozoic craton areas of Australia and North America, the Broken Hill area lies close to and along strike with the Yavapai-Mazatzal orogenic belt, which includes historical mining camps such as Jerome, Arizona, Dawson-Green Mountain Colorado, and farther along the same age-trend, southeastern Labrador. Already intrigued by the potential of the Dawson (Au, Cu) and Green Mountain (Au, Cu, Zn, Ag) mineralized trend, Felderhof and Zephyr President, Loren Komperdo were really encouraged by the work of Iowa State University economic geology profes - sor, Dr. Paul Spry (now technical advisor to Zephyr), a renowned world expert on Broken Hill Type (BHT) silver-lead-zinc depos- its who called Loren Komperdo shortly after the western Green Mountain claims were acquired by Zephyr. While working on the Green Mountain claims with one of his Masters' Thesis students 10-12 years prior, Dr. Spry was taken by the many similarities of Green Mountain with Broken Hill but was puzzled by the mineralization being Cu, Au, Zn rather than Ag, Pb, Zn typical of BHT systems. As such he classified it as a VMS system with Broken Hill affinities. The eureka moment came when Loren Komperdo advised Dr. Spry that the central region of the property – the El Plomo sec - tion – is primarily Ag, Pb, Zn which is a fit with the BHT model. The El Plomo section is believed to be a down-faulted block in which the Ag, Pb, Zn mineralization was preserved relative to the adjacent Green Mountain and Dawsons sections where this had been eroded away. Researching a comparison of the middle El Plomo (Ag, Zn, Pb) section with the Australian Broken Hill mineral belt, it wasn't just the presence of many similar rock types but also the presence of the relatively rare pathfinder mineral, gahnite, a zinc-rich spinel and, as well, a whole constellation of additional similarities in the geologic settings that began to convince them of the possibility of a rich BHT deposit at El Plomo. Dr. Spry pointed out that the high-grade silver and base metal mines such as Broken Hill and Cannington in Australia, are very similar to the El Plomo section of the Dawson-Green Mountain mineralized trend in Colorado. These deposits are classified as Broken Hill Type (BHT) deposits. Cannington and the El Plomo section of the Dawson-Green Mountain mineralized trend have more than a dozen other similarities: a geological setting in Proterozoic pelitic and exhalative rocks metamorphosed to the amphibolite facies (nodular garnet-sillimanite gneiss) associated with thin iron formations (clear magnetic signature); rift-related tectonics; skarn-like mineralogy, no graphite, strong lead-zinc zonation, and high silver to lead ratios. The whole Dawson-Green Mountain trend (included in Zephyr's exploration property) is more than 12 km (7.5 miles) from west to east, and contains the historic (early 20th century) Green Mountain Mine (copper-silver-gold-zinc) on one end, and the Dawson prospect (gold and copper) closer to Cañon City. The Green Mountain massive sulfide was discovered in 1882 and graded some 12.6% copper, 3.8 g/t gold, and 47.6 g/t sil - ver. In the 1980s, U.S. Borax did some work on gold zones in the Dawson area, and Zephyr now has access to all of their informa- continued on page 68 Highly magnetic core from the El Plomo Zone on their Dawson- El Plomo-Green Mountain mineralized trend in west-central Colorado. Photo courtesy Zephyr Minerals Ltd. MINING