Stratiform, banded mineralization of 4 to 8 m is exposed at Almatea. The black sulphide includes galena-sphalerite and pyrite while silicified sulphides only contain pyrite. The Cuatra Minas zones to the west host silicified stockwork principal pyrite mineralization.
Drilling of 37 core holes for 1,938.5 m was completed during past production (approximately 750,000 tonnes from 4 deposits in Table 4). In 1991 2,284.5 m of drilling was completed at Cuatro Minas.
There is a wide exposure of schists underlying the Bramador area. The volcano-sedimentary sequence is represented by dacite, black shale intercalated with mudstone and acidic tuffs. The area has complex structures. Principal alteration is silicification with subordinate kaolinization.
Most of the known historic workings are from the San Jeronimo Gulch on a concession owned by a third party. Total historic production is estimated at 500,000 tonnes with about 70% oxides. MS mineralization is in the form of irregular elliptic lenses that are more or less concordant with the stratigraphy and have widths of 5 to 7 m. The mineralization can be divided into primary and secondary. The primary mineralization (pyrite, chalcopyrite, galena and sphalerite) is fine graned and banded in a gangue of quartz, sericite, chlorite, barite, carbonate and gypsum. Mineralization is vertically zoned with sphalerite-galena in the upper part and pyrite and chalcopyrite at depth. The oxide zone has native gold and silver.
Mineralization is interpreted to be hydrothermal in a submarine environment with a depositional temperature of 200º to 300º C (mesothermal depth). In addition to base metals (zinc-lead-copper), there is accessory gold and silver.
There is a 1.0 to 1.5 m wide pyrite-galena-sphalerite-quartz-calcite vein in the northeast part of this area.
Several historic workings occur near the village of Aranjuez. Historic sampling returned 3-5% Pb+Zn, 87-300 g/t Ag and 0.2-2 g/t Au. Regional geophysical (CSMAT resistivity) survey delineated black argillite horizons. Historic drilling of five vertical holes (1,369.7 m) in selected resistivity anomalies intersected 0.23% Zn and 74.33 g/t Ag over 3 m.
Airborne resistivity mapping shows that the historic workings are co-incident with a 1,200 m east-west trending resistivity low. Analysis of 43 rock samples suggest the presence of silver mineralization with low grade gold (up to 472.9 g/t Ag and 0.44 g/t Au over 1 m). Addition samples were collected during 2009.
La Mina Area
Approximately 6 km east of Bramador is a creek exposure of pyrrhotite (magnetic iron sulphide) dominant MS with sphalerite, galena and subordinate chalcopyrite. Channel sampling by the Company returned 16% Zn, 387 g/t Ag, 6.5% Pb, 0.16 g/t Au and 0.1% Cu across 1.5 m. Mineralization is exposed in a 1 km2 area. Two short adits 50 metres apart have mineralization across 2 m.
El Rubi Area
The known mineralization is located on a third party concession. It is described as controlled by two faults and more or less tabular, irregular bodies with widths ranging from 6 to 30 m and length over 100 m to a depth of 100 m. Lead and zinc are associated with gold and silver in a gangue of abundant disseminated pyrite with calcite, quartz, copper carbonate, hematite and limonite. Mineralization and alteration are described as hydrothermal related to an acid intrusion. Industrias Peñoles produced an estimated 500,000 tonnes in the 1960's.
Porphyry Molybdenum-Copper Target
The airborne geophysical survey identified several EM anomalies. One of them is coincident with a molybdenum soil survey anomaly to the northwest of Aranjuez. These coincident anomalies cover monzodiorite and monzonite porphyries cut by quartz veinlets with muscovite envelopes. Locally there is pervasive muscovite alteration (greisen). Sulphides are oxidized to limonite at surface.
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