The Organullo property is located in Salta province, which is a mining-friendly jurisdiction. The property has an exploration history of almost a century. It was initially explored and mined on a small scale at the Julio Verne Mine in the 1930's, producing copper, bismuth and gold. Mining activity involved excavation of more than 450 meters of workings on 3 levels. Few details of production are available, but concentrates were reported to average 12.5% bismuth and 8.2% copper with gold ranging between 10-20 g/t and sampling on several subsequent sampling programs confirmed the high gold grades found underground. Previous explorers include Fabricaciones Militares (in Partnership with United Nations), Triton Mining Corporation, Northern Orion Exploration, Newmont Overseas Exploration (Chile), Newmont Peru, Artha Resources and Cardero Resource Corp.
Organullo is a large property with widespread and intense alteration indicative of a productive high sulphidation epithermal gold deposit. This property lies along a regional northerly-trending fault linear that controls the localization of mineralization and volcanoes in the region. The Julio Verne Mine is characterized by structure-controlled Cu-Bi mineralization. Associated argillic to advanced argillic alteration extends from the mine eastwards to the Organullo Ridge. Mineralization on the ridge is associated with faulting, quartz veins and silicified rock. On review of the previous work, it is striking that virtually all surface samples contain anomalous gold and many carry anomalous indicator elements. There are very few "dead" samples. The geological relationships suggest that this is near the top of the system with large volumes of underlying rock yet to be explored. The system appears to be large with more than 7 kilometres exposed in a north-south direction. Width is unknown and while some previous workers assumed a long, narrow system, it could extend to the east and west where recent cover hides all the potential. Historical drilling results support the interpretation of a potential bulk-mineable epithermal gold deposit. Reverse circulation drilling returned 200 meters grading 0.47 g/t gold and 189 meters grading 0.66 g/t gold, both from surface. Diamond drilling supports this with an intersection grading 0.66 g /t gold from 19 to 110 meters.
In 2012, a report was completed by GeoRes (an Australian consulting firm) entitled; "Organullo Exploration targets & Pit Optimization", dated June 6, 2012, is authored by Robin Rankin of GeoRes. The work resulted in potential exploration target tonnages and grades of gold at Organullo were reported at lower and upper ranges in southern and northern areas and in total. GeoRes determined two common strike and dip directions, each characteristic of a specific exploration target area. Block models were built for the two target areas (north area and south area). Block sizes were defined to emphasize the narrow vein orientation and were consequently much narrower in the X (east-west) directions than in the Y (north-south) and Z (vertical) directions. Gold grades were estimated into each model's blocks using parameters adapted to the common vein direction in each area. Raw drillhole data was composited to exactly 2.0 meters downhole. No limits were applied to either input data or output estimates and the estimation was unconstrained by geology. Block estimation was done using an inverse distance squared algorithm. Garde estimation scan distances of up to 100 meters in the plane of the veins adequately fills the blocks between drill holes and extended beyond them. Following this evidence, increasing the scan distances by simple multiples produced reasonable figures for ranges of exploration targets. Scan distances of 200 meters and 300 meters were used for lower and upper ranges of exploration targets.
Targets were reported for a variety of gold grade lower cut-off values. Tonnages assumed a constant density of 2.6 t/m3. At a lower gold cut-off of 0.5 g/t the total exploration targets ranged from a lower 19.8 Mt at 0.94 g/t gold (600,000 ounces gold) to an upper 31.6 Mt at 0.92 g/t gold (940,000 ounces gold).
It should be noted that these potential exploration target quantities and grades are conceptual in nature, that insufficient exploration and geological modelling has been done to define Mineral Resources, and that it is uncertain if further exploration will result in the determination of a Mineral Resource.
Despite a long history of exploration, the extent of gold-mineralization at Organullo is not known. Many of the historic drill holes are thought to have been drilled in the wrong orientation due to misinterpretation of the structural setting. Generally insufficient drill testing, low drill recoveries and poorly defined alteration geometries leave significant questions as to the nature, distribution and volume of gold bearing rocks on the property. Much of the property outside the central zone near Julio Verne Mine is under-explored. Further work on outlining property-scale alteration and background geochemistry will assist in determining whether the currently outlined mineralization is the main potential resource on the property or may be peripheral to a larger porphyry style system. The historical Julio Verne Mine is small and is of less immediate interest to modern operators. The drilled area likely represents less than 20% of the defined area of alteration and in itself would be of interest to a serious explorer or mid-tier producer. With alteration in the remainder of the property extending at least 7 kilometres along strike and otherwise obscured under recent cover, the exploration target could be much larger.
Cardero Argentina originally acquired Organullo in 2004. The property was acquired from a private vendor and the purchase price was 70,000 shares in Cardero Resource Corp. On September 9, 2011, Cardero entered into an option/joint venture agreement with Artha, whereby an Argentinean subsidiary of Artha could earn a 55% working interest in the Organullo property, and thereafter form a joint venture with Cardero Argentina a wholly owned subsidiary of Cardero. On September 11, 2013, Artha officially notified Cardero that Artha did not incur the required expenditures and consequently dropped its option to acquire any interest in the property.
In May 2015 Cardero Resource Corp. completed a reverse takeover of Artha Resources Corp. selling its assets (including Organullo) in the Argentine subsidiary, Cardero Argentina to Artha. Artha was subsequently renamed Centenera Mining Corp.