ASC Bolivia LDC Sucursal, an indirect whoully owned subsidiary of Silver Elephant, holds a 100% exclusive right to develop and mine at the Pulacayo and Paca concessions for up to 30 years from the date of Incorporation against certain royalty payments.
- subscription is required.
Summary:
The Pulacayo and Paca deposits have been classified as epithermal deposits of low to intermediate sulphidation state. Deposits of this type have been extensively researched and various summary publications that document specifics of the association are available. Examples of these include Lindgren (1922), White and Hedenquist (1994), Corbett and Leach (1998) and Corbett (2002). More recently, Arce (2009) classified the silver-zinc lead deposits associated with the Pulacayo dome as being of transitional association between high and low sulphidation types. The following discussion of deposit type incorporates attributes of the Pulacayo vein and stockwork style deposit as well as the Paca stratabound mantos and breccia style deposits. The premise is that these deposits are similar in being directly related to development of the discrete Pulacayo and Paca volcanic dome complexes that are of comparable age and similar magmatic affinity.
Silver, lead and zinc mineralization at the Pulacayo and Paca deposits reflects a low to transitional sulphidation epithermal polymetallic system hosted by sedimentary and igneous rocks of Silurian and Neocene age. The Silurian sedimentary section underlies the volcanics and includes diamictites, sandstones and shales. The Neocene rocks are predominantly volcano-sedimentary in origin and include conglomerates, sandstones, rhyolitic tuffs, dacitic-rhyolitic domes, andesitic porphyries and andesitic flows.
The Pulacayo Project that includes both the Pulacayo and Paca deposits is located on the western flank of a regional anticline that affects sedimentary and igneous rocks of Silurian, Tertiary and Quaternary ages on the western side of the Cordillera Oriental, near the Cordillera-Altiplano boundary.
Mineralization
The Pulacayo and Paca deposits are considered to be related to the same mineralizing event that is associated with development of the associated Paca and Pulacayo volcanic centers. For completeness, summary descriptions of mineralization characterizing each deposit are presented below under separate headings.
Pulacayo Deposit
The Pulacayo deposit is considered an example of a sub-volcanic epithermal mineralization system showing well developed vertical metal zonation. The main mineralized vein and stockwork system that comprises the deposit developed on the southern flank of the dacitic Pulacayo intrusive dome and shows a surface strike dimension of approximately 2700 m. At Pulacayo, east-west striking faults are interpreted to have acted as a conduit system for mineralizing fluids, with sulphide precipitation in open spaces to form veins and along fractures or by replacement to form zones of disseminated mineralization. Changes in temperature, pressure and redox state between the wall rock and fluid are thought to have influenced the style and intensity of mineralization. As such, silver lead and zinc mineralization at the Pulacayo deposit is typical of a high level epithermal system that in this case is hosted by sedimentary and intrusive rocks of Silurian and Neocene age.
The principal mineralized structure at Pulacayo is the TVS which has historically been the main silver producer of the mine. The TVS is a large structural stockwork vein system that trends eastwest and dips 75° to 90° to the south. The high-grade parts of the TVS were historically mined as single veins over widths of 1 m to 3 m but transitions occur from this setting into zones of complex quartz-sulphide or sulphide vein arrays that include conjugate veins, veinlets, stockworks and disseminated sulphides that range in width from less than a metre up to 120 m.
Mineralization of economic interest at Pulacayo is predominantly comprised of sphalerite, galena and tetrahedrite in sulphide-rich veins and stringers that are accompanied by locally abundant quartz, barite and pyrite. These veins range from a few cm to 3 m or more in thickness and disseminated sphalerite, galena and tetrahedrite typically occur in wall rock between veins. Disseminated mineralization is preferentially developed around and between veins hosted by andesite. To date, the TVS system has been continuously proven by a combination of mining, drilling and surface exposure along a strike length of about 2700 m and to a vertical depth of 1000 m below surface. Mercator considers the deposit to remain open in both strike and dip components at the effective date of this report. The first 450 vertical m of the TVS is hosted by andesitic volcanic rocks and the remaining 550 vertical m is hosted by underlying Silurian sedimentary strata. Veins at Pulacayo commonly contain semi-massive to massive sulphide and show internal features such as compositional banding, crustiform texture and drusy character. They also frequently exhibit vuggy texture and have local infillings of quartz and barite.
Paca Deposit
The Paca deposit is spatially related to the contact zone of the Paca volcanic dome which is comprised of porphyritic andesite and dacite units and related volcanic breccias that were described above.
Silver-zinc-lead mineralization at Paca occurs primarily within an argillic to advanced argillic alteration envelope that affects both Paca dome igneous lithologies and surrounding host sequences. Silicification and alunite development are also well developed in association with some portions of the deposit. The Paca deposit presents a core zone of mineralization that correlates closely with an irregularly shaped body of altered and brecciated andesite and country rocks that closely follows the contact zone between the Paca dome andesite and the shallowly north-dipping host volcaniclastic sequence. Adjacent to this, stratabound replacement style (“mantos”) mineralization is present within the shallowly northdipping host volcaniclastic sequence at several elevations. Mantos mineralization merges with that seen in the central breccia zone but is typically lower in all metal grades.
A polylithic conglomerate unit that outcrops in the deposit area is also mineralized and shows a strong imprint of silicification represented by micro-crystalline replacement style silica in various forms.
Mineralization associated with discrete veins of significant width and lateral extent is not pervasively present at Paca. Mineralization more typically occurs in irregularly spaced discrete fracture systems as well as in matrix replacement sites. The mantos style mineralization is primarily represented as finely disseminated, fine grains and aggregates of silver, lead and zinc sulphide and sulphosalt phases, accompanied by others such as manganese oxide and barite. Argillic to advanced argillic alteration phases are pervasively present in areas of significant metallic mineralization. Mineral phases commonly recognized at Paca in association with metal grades of economic interest include sphalerite, galena, silver sulphosalts, tennatite, smithsonite, barite, manganese oxide, gypsum, jarosite, specularite, cerussite, dolomite aragonite and calcite.
Production
2023 data reflect the volume of production for the period from the start of mining on October 17, 2023, to the end of the fiscal year on March 31, 2024.
| Commodity | Units | 2024 |
|
Silver
|
t
| .... |
All production numbers are expressed as ore.