Tolita
The TOLITA gold-copper prospect is located 110 kilometers SE of the city of Copiapó, and 25 kilometers SW of the Cerro Casale project (Barrick-Goldcorp).
It is a «porphyry-gold-copper» prospect. The mineralization and the hydrothermal alteration are associated to dacitic porphyries that intrude a sequence of sedimentary rocks in the base and dacites and andesites in the roof. The rocks are locally affected by argillic, potassium and silicification alteration.
Geology
The basement of Tolita is constituted in the South and East by Red Beds sediments of the Upper Cretaceous. In the Northwest there is a sequence of lavas and sediments intercalated. The basement is intruded by a feldspar porphyry in the North Central part of the concession and further south by sub volcanic dacitic porphyries. There is a stock of diorite and another of granodiorite. Numerous dacite dykes cut through the entire sequence.
The prospect is located in a structurally complex area, with the development of a Riedel-type system, with formation of extension and compression structures. The structural system exercises control in the distribution of alteration and mineralization.
There are two types of mineralization-alteration directly associated with the evolution of the dacitic porphyry site, one with the development of an Au-Cu porphyry system (Maricunga environment); and another that occurs laterally to the porphyry and lodged in sedimentary rocks, which consists of a central structure (vein) N 35º E, from 4 to 8 m of width, with economic values of Au-Cu.
Aerial magnetometry defined a regional structure and magnetic lows
Soil geochemistry in 100×50 grid (928 samples) defines an anomaly of Au and Cu of 1,300 meters NS by 800 meters EW, associated with a Northeast structural system.
The drilling program (which was left unfinished) started at the north end of the area and three RC drill holes were drilled with a total of 628 m. The most interesting cut sections are: 70 m with 0.33 g/t Au, 16 m with 0.65 g/t Au, 28 m with 0.33 g/t Au and 12 m with 0.46 g/t Au.
Expectations:
In TOLITA it is expected to discover a deposit of the type «Porphyry of Gold – Copper» of Maricunga environment
It is estimated by the geochemistry (high values of As, Sb, Pb, Zn), by the hydrothermal alteration, by the mineralization on the surface and by the 3 drill holes carried out, that there is a cover of 50 to 150 m of altered rock, poor in gold and copper (medium to strong anomalous values), locally sterile, over a deeper deposit
The existence of a vein of 4 to 8 m of power and with economic values would possibly indicate a mineralization in structures type La Pepa deposit (Meridian)
In TOLITA we recommend an IP – Resistivity or Csamt study, in the areas of structural system junctions, most of which are covered by colluvium and do not have trenches or drill holes, and a campaign of 8 drill holes of 500 m each.
