Bolivia Gold - Golden Hill
Underexplored Orogenic Gold System
Golden Hill comprises one concession fully permitted for mining and drilling and located within the underexplored Bolivian Precambrian Shield. Mineralization is of greenstone hosted orogenic gold type.
Strategically Located
Golden Hill Property is located in the underexplored Precambrian Shield, Bolivia. Golden Hill is located on a crustal scale structure which hosts at least six other significant gold occurrences and deposits, at the juxtaposition of several different lithologies, including meta-volcanics with abundant iron-rich ferromagnesian minerals. From a regional perspective and comparison with other greenstone belts worldwide, Golden Hill is an attractive project.
Pro-Mining Community and Fully Permitted
The local community is pro-mining and in favor of project development. The community is currently providing support workers to assist with Mantaro's field work. The property is fully permitted for both drilling and mining with no community agreement needed to advance the project.
Easy Access with Established Camp
Golden Hill is located 15 kilometers directly to the east of the Historic mining town of San Ramon — 140 km Northeast of Santa Cruz, Bolivia’s second largest city, for a travel time of approximately 3.5 hours via paved highway. The area is typical of sub Amazonian terrain with year round operating capability. Access throughout much of the concession is good. The property includes an operational 50 t/d gravity circuit processing plant and a well maintained fully functional exploration/mining camp, which includes an office, canteen, mechanical workshop and dormitories with capacity for around 20 workers.
Permitted to Mine and Drill
Prior to the option agreement with Mantaro, one of the main quartz veins at La Escarcha was being mined at a rate of up to 25 tonnes per day to a depth of 60 meters. The mined material was processed at site and gold recovered using a combination of simple gravity circuits. The mine permit at Golden Hill allows for production to be increased subject to the Company completing its own economic studies on the project and to sufficiently fund any upgrades.
2022 Drill Testing by Mantaro
To date four major gold mineralized zones have been identified across over 4 km strike length by surface oxide mining, historical trench sampling and mapping. La Escarcha, Gabby, Garrapittilia and Brownfields. Historical drilling on the property was limited to the immediate La Escarcha Pit area, with 1620 m completed historically between eight diamond drill holes.
In 2022, Mantaro completed 21 diamond core drill holes at Golden Hill for a total of 3009 m of drilling. Best results reported to date include:
5 m at 7.57 g/t gold from 87 m downhole (including 3.66 m at 10.16 g/t gold from 88.34 m) in hole GH0005 (reported November 9, 2022);
3.4 m at 8.27 g/t gold from 67.6 m downhole (including 2.02 m at 11.82 g/t gold from 67.6 m) in hole GH0005 (reported November 9, 2022);14.0 m at 3.57 g/t gold from 105 m downhole (including 8.8 m at 4.91 g/t gold from 108.1 m) in hole GH0005 (reported November 9, 2022);
4.69 m at 5.15 g/t gold from 171.51 m downhole in hole GH0003 (reported October 5, 2022); and
4.00 m at 6.46 g/t gold from 76 m downhole in hole GH0006 (reported October 26, 2022).
Deposit Type
Mineralization at Golden Hill is of Greenstone Hosted Orogenic type. Gold is contained within one to five meter wide sub-vertically dipping quartz shear zones, typically found along faults at the contacts between mafic volcanic and metasedimentary units of pre-cambrian age. These deposit types have the potential for kilometres of strike extension and kilometre + depth potential. The vein system has been traced for over 4 km on the property, located in the hanging wall of a regional controlling fault to the west. This style of mineralization can be observed across the region and notably 2 km to the north of the property at the Puquio Norte gold mine which produced over 350 koz Au between 1997 and 2003.
Regional Geology
The Bolivian Pre-Cambrian shield is larger than the Abitibi greenstone belt in Canada, yet the Bolivian shield has produced <10 Moz Au compared to 170+ Moz Au in the Abitibi from over 100 mines since 1901. Similarly, the gold endowment of the West African shield, the greenstone belts of NE South America (Venezuela, Guyana, Suriname and Brazil) and the Yilgarn province of Western Australia much greater than equivalent areas of the Bolivian shield as the Bolivian shield remains largely under-explored.
As with other greenstone belts and mineralized provinces worldwide, mineralization in the Bolivian shield is hosted along major crustal structures which juxtapose different lithologies against each. Regional-scale structures serve to focus mineralizing fluids, whilst rocks of different competency, provide a regime for both ductile and brittle deformation and thus creation of space for deposition of quartz, pyrite and gold. Mafic volcanics are especially favourable hosts due to the high iron content which reacts with sulphur in mineralizing fluids to form pyrite — causing gold to precipitate from the mineralizing fluids.
Property Geology
The Golden Hill concession is centered on a broadly north-south trending regional structure that hosts the La Escarcha underground mine and Gabby, the Garrapatillia and Brownfields workings and gold-bearing vein occurrences in its western hanging wall. The same structure hosts numerous saprolite gold and hard rock gold deposits to the north and south of the Golden Hill concession over a strike length of at least 25 kilometres — underpinning the significant control the structure exerts on gold mineralization.
A northwest-trending splay of this structure hosts areas of alluvial and saprolitic/hard rock workings within the Golden Hill concession and immediately to the north. At least six strike kilometers of these structures are known within the concession — in addition to the four kilometers between La Escarcha and Brownfield which have been mapped in detail. Known mineralization and surface anomalism is open along strike on all structures.
Mineralization between La Escarcha and Brownfields is characterized by a series of broadly parallel, north-south trending, very steeply dipping quartz veins that are between 1 to 5 meters wide. Mineralization is hosted in mafic metavolcanics, at the contact of metavolcanics and metasediments, and within metasediments.
Veins are well exposed in underground workings at La Escarcha where they comprise multiphase white quartz and slivers of wall rock which are fracture oxidized. Veins are up to 5 meters wide and contain significant visible gold. Most gold appears to be free hosted in fractures within quartz and pyrite.
