CMJ's Yarumalito property has the potential to host large tonnage, bulk mineable gold-copper mineralization, as well as high grade structurally controlled gold mineralization that may be amenable to underground mining technology.
Project Summary:
CMJ's exploration at Yarumalito is focused on gold-copper porphyry-related mineralization such as that found at other Colombian deposits, including Marmato, La Colosa, and Angostura. The presence and extent of this style of alteration and mineralization has been mapped and characterized with multiple programs of surface rock chip and soil sampling. The rock sampling and mapping of exposures in road cuts, trenches, and drainages has provided detailed information in some areas. On a broader scale the extent of the mineralization is indicated by soil auger/rock chip sampling and wide spaced MMI soil sampling. Targets generated by this surface work are now being drill tested with CMJ's 2010 drilling program. This drilling is also expected to create a basis for determining the extent of oxide gold-copper mineralization on the property.
A second exploration focus for the summer of 2010 includes further surface sampling and drilling on some of the higher grade fault zone hosted (vein-style) gold zones in and around the porphyry gold-copper mineralization. This style of mineralization has been prospected and mined Yarumalito and in the Marmato District for hundreds of years, and has the potential to add higher grade material to any future production scenario.
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 dating back before Spanish colonization of the area in 1500's. In the Mina Yarumalito area, high grade, vein hosted gold deposits were discovered in 1988, and produced approximately 13,000 ounces of gold from small scale, private mining activity. Mining was halted in 2002 due to the prevailing low precious metal prices at the time.
Land and Legal:
The property is covered by four exploration and two exploitation licenses covering 1,448 hectares. Colombian Mines has a purchase option agreement with the underlying mineral rights holder to acquire a 100% interest in the property.
Geology and Mineralization:
The geology of the Yarumalito 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--west structural zones are a primary control on alteration and mineralization at Yarumalito.
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 system, and 3) high-grade, structurally controlled mineralization. The major veins are sub-parallel with 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 veins range from 0.2 to over 3 meters, and with the 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.
2010 Exploration Program:
Core drilling has been initiated in the "La Escuela" area from three separate sites. An additional core rig has been planned for the Balastreras area, where two sites have been located. Typically, multiple angle core drill holes are drilled from each site. Once this initial drilling has been completed, a decision will be made as to the location and extent of the next stage of the program. Drilling is also planned to test some of the higher grade zones during the summer 2010 phase of the program. Additional detailed information on the current exploration program and updated drill results can be found in periodic news releases on this website.
Yarumalito Technical Report:
Please click on the following link for the 2008 Yarumalito Technical Report:
Click to view in PDF format
