Nevada Sunrise Begins Geochemical Survey At Coronado VMS Project
VANCOUVER - Nevada Sunrise Gold Corporation reported that a geochemical sampling program is underway at the Coronado VMS property, located in the Tobin and Sonoma Range of Pershing County, Nevada, approximately 48 kilometers (30 miles) southeast of Winnemucca. Coronado is located on a geological trend that includes the past-producing Big Mike open pit mine, where high-grade copper was discovered resulting in copper production.
Nevada Sunrise plans to collect approximately 160 soil samples from a grid established across the surface trace of the Coronado South conductor, a strong airborne electromagnetic (EM) anomaly detected by the Company's helicopter-borne geophysical survey commissioned in 2018. This initial soil survey program represents the Company's first test of the SGH process, which has been reported to detect buried sulphide mineralization at depths up to 500 metres. Results from the survey will be integrated into the Coronado target matrix for a future drilling program.
Coronado currently consists of 133 located unpatented claims totaling approximately 2,748 acres located over an interpreted trend adjacent to the historic Big Mike open pit copper mine that lies within the Middle Pennsylvanian to Late Permian-age Havallah volcanic-sedimentary sequence. The Company's land position controls an important seven mile-long regional trend along which several volcanogenic massive sulphide (VMS) showings, one high-grade copper deposit (Big Mike mine) and at least two high priority airborne Versatile Time Domain Electromagnetic ("VTEMTM") anomalies have been identified within the Early Pennsylvanian – early Late Permian Pumpernickel Formation of the Havallah sequence.
The Havallah sequence in general and the Pumpernickel Formation in particular have received little attention for base metals exploration since the 1970s and have been virtually ignored by resource companies operating in Nevada who are focussed only on gold exploration. The lack of an exploration model and failure to utilize modern ground/borehole/ airborne electromagnetic surveying systems may be key reasons why no new VMS discoveries have been made to date in Nevada. The probability that additional high-grade, commercially viable deposits are present within this sequence to the northwest of Big Mike is relatively high when compared to other VMS districts in the world.
Big Mike was discovered in the 1930s when a shallow, oxidized portion (gold-bearing gossan) of the deposit was located by prospectors. The area was explored further in the late 1960s by Cerro Corp. and a deeper (greater than 300 feet, or 91 meters) high-grade, massive sulphide lens was discovered by diamond drilling. The deposit was considered a supergene-enriched, Cyprus-type VMS occurrence. In 1969, Cerro Corp. published a historical resource estimate of 634,000 tons grading 3.41% copper, which included 74,000 tons of massive sulphide ore grading 11.78% copper, and 380,000 tons of oxide and mixed ore grading 3.16% copper1.
1This historical estimate, which is dated February 21, 1969, uses categories that are not consistent with National Instrument 43-101 ("NI 43-101") and cannot be readily compared to NI 43-101 categories. A qualified person has not done sufficient work to classify the estimate as a current resource and Nevada Sunrise is not treating the estimate as a current resource estimate. A portion of the ground on which this estimate was based was subsequently mined. However, the historical resource estimate is relevant to guiding the Company's exploration plans and provides geological information regarding the type of mineralization that could be present in the Coronado area.
In 1970, Ranchers Exploration and Development Company (Ranchers) developed the high-grade portion of Big Mike with an open pit mine that produced approximately 25 million pounds of copper in 100,000 tons of ore grading 10.5% copper, which was shipped directly to smelters in West Germany and Japan. Heap leaching of lower-grade disseminated copper ore was also carried out by Ranchers; approximately 300,000 tons of mineralized rock was treated. Historical sampling also shows the presence of cobalt at Big Mike, with values in the deposit ranging up to 2,500 parts per million (0.25%) cobalt.