Based on results of diamond drilling completed to date, there are at least sixty-two mineralized lenses at Bolivar. These lenses range from less than a metre up to 20 m in thickness, extend 25 m to 100 m along strike and up to 100 m in the vertical dimension. Geological interpretation of the mineralized zones on cross sections also indicates mineral zoning at Bolivar. Closer to the contact with the granodiorite intrusive, a relatively thicker copper-rich zone of mineralization, with low zinc values, appears to be prevalent. A narrower zone of similar copper-rich mineralization also occurs very close to the contact with the intrusive. Higher up the stratigraphic section, several lenses of zinc-copper mineralization are present. This type of zonal distribution of sulphides associated with skarn-type alteration assemblages of calc-silicates and iron-oxides are described at other mineral deposits in the Southwestern United States (Meyer and Hemley, 1967) and in other parts of the world (Ray and Webster, 1991).

Currently, there are at least eleven mineralized areas within the seventeen mineral concessions of the Bolivar project area. These are:

• Bolivar High Grade (Alta Ley) Zone
• Bolivar Zona Sur
• El Gallo
• Bolivar Noroeste (Northwest)
• La Increible
• La Pequeña
• San José de Piñal
• La Montura
• La Narizona/El Val
• Central Area
• Breccia

These mineralized zones are hosted within two main structural zones: the El Val – La Pequeña Structure and the San José del Pinal type vein structures. The El Val-La Pequeña Structures includes the Rosario, Fernandez and Brecha Linda trends.

Rosario Trend

The Rosario mineralized system is approximately 350 m long, with varying width from less than one metre to eight metres. It forms part of the El Val-La Pequeña Structure. Individual ore shoots within the lenses range from 20 m to 50 m long horizontally, and from 20 m to 50 m vertically. Strike orientations are generally north-northwest, and dips are from 20° to 40° to the northeast. All economic copper and zinc mineralization discovered and mined to date lies within 300 m of surface. Post-mineral faults locally disrupt and offset the mineralized zones.

T he Rosario Trend is situated along the right flank of a northwest trending valley, which is part of the El Sausal-Cieneguita Lineament. Detailed cross sections and level plans of the Bolivar Mine area are discussed under a separate section of Mineral Resources. Near the shaft of the Bolivar Mine, the area exhibits typical skarn-related zinc and copper mineralization. Currently, there are at least thirty-three semi-massive to massive sulphide mineralized lenses recognized within this structure. From northwest to southeast, these are:

• Brecha Linda Oeste: twelve lenses
• Brecha Linda Este: ten lenses
• San Francisco: four lenses
• Bolivar Sur/El Gallo: six lenses
• Magnetic skarn: one lens

In addition to the above, at least fourteen mineralized lenses are recognized at the Bolivar Noroeste zone, situated from 100 m to 300 m north of the Bolivar shaft.


Fernandez Mineralized Structure

The Fernandez structure trends east-southeast and hosts the mostly gently dipping Fernandez Titanic and Selena lenses. It is situated just east of the Bolivar shaft and has been partly developed by eight sublevels. These are sublevels 835, 845, 848, 861, 854, 869, 870, and 906. Sulphide mineralization is confined to a 25 m wide structure, which has been traced some 100 m along strike in silicified limestones and andesitic rocks and that extends approximately 100 m in the vertical dimension. Recent diamond drilling has intersected this structure, with mineralization ranging from 7.16% Cu, 21.9% Zn, 30.3 g/t Ag and 0.06 g/t Au over 1 m to 3.6% Cu, 1.32% Zn, 250.5 g/t Ag and 2.16 g/t Au over 9 m in Drill Hole DB04B061. Recent drilling also suggests that this mineralized structure may extend further to the southeast, towards La Increible deposit. Dia Bras plans to test this target area by drilling.

Brecha Linda Structure

Mineralized lenses of the Brecha Linda Structure are oriented in north-northeast direction, but define an east-southeast-west-northwest trend, similar to the Fernandez Trend.

El Val – La Pequeña and La Narizona Structures

The mineralized zones within the El Val-La Pequeña and La Narizona structures are readily seen from the air and are situated along the cliffs with malachite staining as well as at relatively more resistant calc-silicate outcrops with abundant garnet, epidote and magnetite, which intermittently extend for more than 6 km along strike but may have limited (20 m to 30 m) lateral extent. From northwest to southeast, these are:

• La Increible Mine: This prospect is situated approximately 500 m east of the hill that hosts the Bolivar deposit. Mineralization consists of at least twelve small pods of massive sulphides (sphalerite and chalcopyrite) within an east trending, 1 m to 2.5 m thick zone, hosted by grey massive limestone, which extends up to 100 m in an easterly direction, where the La Pequeña Fault cuts it. Previous development work at La Increible consists of an adit and minor old underground workings, including two small stopes. Outside the adit and along the gravel road, there is extensive pyritization within the altered granitic rocks. Typical endoskarn-type alteration includes epidotization, silicification and magnetite with associated pyritization. Pyrite is present as fine to medium-grained disseminations, as well as fracture coating material. This zone of pyritic material continues for about 700 m along the gravel road.
  
  
• El Val Medio: At this locality, the El Val Structure consists of an up to 50 m wide skarn zone at the contact between limestones and andesites. The mineralized zone is 1.5 m to 5 m wide, has a moderate dip to the northeast, and contains massive sulphides, such as chalcocite, chalcopyrite, bornite and sphalerite, with conspicuous malachite staining.
  
  
• La Pequeña: This area is situated some 1,300 m east of the old La Increible adit. Mineralization is similar to, but narrower than that at El Val Medio. At this locality, the mineralized zone is 0.5 m to 1 m wide, has a moderate dip to the northeast and contains massive sulphides, such as chalcocite, chalcopyrite, bornite and sphalerite. Results of recent chip sampling by Dia Bras include grades ranging from 0.01% Cu, 0.41% Zn, 0.03% Pb, 15 ppb Au and 5 g/t Ag to 2.22% Cu, 25.6% Zn, 0.22% Pb, 120 ppb Au, and 152 g/t Ag.
  
  
• El Val: This area comprises the southeastern part of the El Val Structure and consists of a northeast dipping skarn zone up to 200 m wide. The skarn is cut by narrow north trending felsic dikes and, at its lower contact, is grey, fine-grained, with almost hypidiomorphic texture (endoskarn). Sulphide mineralization at El Val occurs near the contacts with felsic dikes, within alteration/mineralization haloes 10 m to 20 m wide. The sulphides occur as small pods within the haloes.