Newrange Gold Corp.’s (NRG) Yarumalito project covers a large gold dominant porphyry complex composed of multiple intrusive centers. The property covers 1,456 hectares of highly prospective terrain 11 air kilometers north of the famed Marmato District, along what is commonly termed the “Mid Cauca Belt” a segment of the Andean Porphyry Belt that stretches from Chile, through Peru, Ecuador, Colombia and Panama. Exploration work to date consists of property wide geochemical and geophysical surveys, extensive geological mapping and more than 18,000 meters of drilling. This work defines a large mineralized zone more than 400 meters wide, 1,000 meters long and open to depth below 385 meters as per recent drilling.
Newrange owns a 100% undivided interest in the Contract Concession and there are no underlying royalties or payments to third parties.
Location and History:
The Yarumalito property is situated in the Marmato Mining District, approximately 11 kilometers north of Marmato mountain, and 110 kilometers south of the city of Medellin. The Marmato district hosts a number of productive gold-silver properties, and is one of Colombia’s most famous mining districts with historic production pre-dating Spanish colonization of the area in 1500’s. High-grade, vein hosted gold deposits were originally exploited by the Spanish however after Colombia’s independence, mining appears to have ceased in the area. High-grade vein mineralization on the property was re-discovered in 1988, and produced approximately 13,000 ounces of gold from small scale, private mining activity until mining was halted in 2002 due to the prevailing low precious metal prices.
Land and Legal:
The property is comprised of a single consolidated Concession Contract covering 1,456 hectares issued in the name of the Company’s wholly owned Colombian subsidiary.
Geology and Mineralization:
Geology in the area is dominated by Tertiary age, andesite to dacite porphyry (granodiorite) intrusive rocks. Locally these intrusives occur as stocks and apophyses that mineralize older sedimentary and volcano-sedimentary host rocks, with the entire sequence overlain by andesite flows and tuffs. Regional scale northwest and east-northeast structural zones are a primary structural control on alteration and mineralization.
Three distinct types of mineralization have been identified on the property, and include 1) gold-copper porphyry type mineralization, 2) contact related mineralization in sediments intruded by the porphyry systems, and 3) high-grade, structurally controlled mineralization. Major veins are aligned with both northwest and east-northeast structures, tend to be sub-parallel with steep to near vertical dips.
The primary northwest trending structural zone ranges from 250 to 400 meters in width, and can host multiple veins and numerous lesser veinlets which form a structurally controlled stockwork. The true thickness of the major individual veins ranges from 0.2 to over 3 meters. Smaller veinlets associated zone of fracturing and stockwork style mineralization have produced a gold anomaly up to 400 meters wide; these fractures typically contain gold-related sulfide minerals such as pyrite, chalcopyrite and sphalerite. Alteration is dominated by widespread pervasive propylitic, with local sericitic and potassic zones, and is similar to other intrusive hosted deposits in Colombia and the South American Cordillera.
Mineralized structures associated with the east-northeast structures commonly exhibit intense clay alteration with abundant sulfides including pyrite, stibnite, sphalerite and rare chalcopyrite. The Culebra Shear Zone, one of the most continuous structures related to this structural family contains individual vein drill intercepts to 1.9 meters at 33.75 grams gold per tonne. The Culebra shear is exposed intermittently over a strike length of 5 kilometers with a visible dip development in excess of 1,000 meters.
Newrange has completed property wide airborne magnetometry and radiometric geophysical surveys, conventional and Mobile Metal Ion (MMI) soil geochemistry, extensive rock geochemistry surface channel sampling of outcrops and trenches, extensive geological mapping, petrographic studies, large diameter column leach tests and diamond core drilling. Exploration has been focused on identifying gold-copper porphyry related mineralization such as that found at Marmato and La Colosa. To date, more than 18,000 meters of drilling has been completed, mostly in the Escuela target zone. This work indicates a significant volume of mineralization with potential to host 2.8 to 3.2 million ounces of gold and 20 to 30 million ounces of silver. Metallurgical work on 1.5 metric tonnes of mineralized drill core composited from the Escuela zone achieved 91.6% recovery of gold on mineralization when crushed to ½ inch (12.5 mm) from the oxide zone. Transition and sulfide mineralization yielded 80.6% and 63.0% recovery, respectively, on mixed and sulfide ores crushed to 10 mesh (1.5 mm).
A secondary exploration focus is the higher grade fault zone hosted (vein-style) mineralization of the 5 kilometer long Culebra Shear Zone. Exploration of the Culebra zone has only been conducted when it could be conducted in conjunction with exploration of the porphyry focused exploration.
To date drilling has identified an extensive area of mineralization primarily hosted in hornfelsed units of the Combia formation, a volcano-sedimentary formation with locally extensive distribution. The Escuela zone has been drilled on nominal 100 meter drill spacing over an area roughly 400 meters wide, 1,000 meters along strike and to depths of 385 meters. Mineralization commonly extends from surface to the bottom of drill holes and remains open along strike and to depth.
The Culebra Shear Zone is seen to form an abrupt, steeply dipping northern boundary to the Escuela target. Six scout drill holes in the Balestreras target contain similar mineralization and indications are that Balestreras represents a structurally offset portion of the Escuela zone. It is likely the Balestreras zone contains mineral potential similar to that found in the Escuela zone.
Yarumalito Technical Report:
Please click on the following link for the 2008 Yarumalito Technical Report:
Yarumalito Project Technical Report