Zone El Portón- (Potasisium)
Location and antecedents of the area.
In the area of the gas deposit called “El Portón”, (60 km to the east of the city Buta Ranquil, Department of Pehuenches) and within the potassium mining properties “La Fuente I” and “La Fuente II” took place the initial phase of an exploration program that aimed to develop there a potassium underground mine. The properties limit to the north (37º07’ LS) with a river called Colorado and with a total of 46 mining properties that cover a surface of 4.600 hectares. Towards the south they get up to the latitude of 37º 13’ LS and the meridian 68º37’ LW sets the east limit and the 69º40’ LW determines the west border of the mining properties.
The area was researched and assessed by Danderfer (2002, 2006) who relating the surface geology and the data of gamma-ray profiles of 21 wells (exploration and/or production) of YPF-REPSOL located within the properties of Minera Cordillera del Viento, identified two mineralized complexes of sylvite. One of them at 357 mbbp while the thickest one starting at 903 mbbp, in an area of approximately 4,5 Km2, estimating a geological reservation of 100 Mt of Cl K, with probable grade of 25-30% K2O. According to the dip conditions of the mineralized horizons (22º to 23º to the E) and to its depths in the considered area, Danderfer (2006) suggested the alternative of exploring the resource at first for conventional mining and in further stages to explore towards the east the deep horizons for exploitation by dissolution, estimating that these resources could exceed about 200 meters of sylvite.
Afterwards, the Project was evaluated again by geologists of the company K+S (Germany) including inspections and visits to the area of the mines from October of 2007 to June of 2008. Together with the analysis of new wells profile and records of 2D seismic in the area of influence of the mineralized complex, the final evaluation led to the decision of beginning the exploration for conventional mining.