Avesoro established in 2013 as a subsidiary of MNG Group of Türkiye, Bea Mountain Mining Corporation (BMMC) operates as the flagship subsidiary of Avesoro in Liberia. BMMC holds an extended 25-year Mineral Development Agreement (MDA) with the Government of Liberia, providing the necessary long-term framework and stabilization of taxes and duties.
Avesoro Resources was delisted at TSX in January 2020.
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Summary:
New Liberty Stratigraphy
The New Liberty Project is underlain by three main stratigraphic units, which are further subdivided into minor zones of varying mineralogical assemblages. The geology is dominated by tremolite-chlorite- actinolite-talc ± magnetite rich meta-ultramafics, sometimes with phlogopite, and flanked by migmatitic gneisses.
The Footwall Complex (FWC) rocks are similarly banded, but the bands have a wider zone of foliated leucoratic gneiss and contain less but larger concentrations of hornblendic gneisses.
The silicified metamorphosed ultrabasic suite (SMUS) is the principal host to the gold mineralisation, and generally contains quartz, chlorite and amphibole, and a host of mafic minerals, including talc.
At the contact separating the HWC and FWC from the SMUS are transitional rocks, named here as garnet phlogopite + actinolite gneiss, which have a strong schistosity and coarse grain size. This unit is also found within the ultramafic sequence.
Syn-to-late tectonic aplites, pegmatites and granitoids that occur within the system are heterogeneous and show significant variations in deformation style relative to the host rocks. Greisens and pegmatitic granites intrude the ultramafics. The variable angles these granite contacts make with the units suggest that they were intruded both along the strike of the zone and into crosscutting fractures, faults and secondary shear zones. The relative ages of these intrusive bodies and their relationships to mineralisation are not known at this stage.
Alteration and Mineralisation
Within the ultramafic unit, silicification is found proximal to the mineralisation, within the immediate hangingwall and rarely in the footwall gneisses. Other alteration styles associated with the mineralisation include the presence of phlogopite as well as chlorite within the mineralised zone, and an associated sulphidic bleaching of the rocks linked with the destruction of magnetite.
These features point to a pathway for the mineralising fluids which was active over a long period of time. The deposit shows the classic signs of sulphidation, with iron sulphides (mainly pyrrhotite) replacing the magnetite and it has a low sulphide content with sulphides forming between 0.1% and 1% of the mineralised zones.
Relationships have been established between magnetite depletion, silicification, phlogopite alteration and gold mineralisation.
Multi element analyses of cores have highlighted a clear association between gold and arsenic, sulphur, nickel and tungsten in the mineralised zones. Enhanced values of magnesium, sodium, potassium, rubidium and barium occur along the margins of the mineralisation. It is hypothesised that the gold- bearing metamorphic fluid may include a granitic component in its evolution.
Vast majority of the mineralisation at the Project is hosted within the altered parts of the sheared ultramafic rocks. Pyrrhotite, gersdorffite and arsenopyrite are the main sulphides with occasional pyrite and rare chalcopyrite or pentlandite. Metallurgical tests of the mineralised sections carried out by Lakefield Research Limited (Lakefield, 1999b) indicated that the gold is free in form. Gold mineralisation occurs in zones of variable thickness, with average widths of 10 m, and is nearly continuous along 2 km of strike.
Through the history of exploration at the Project, particular local concentrations of higher-grade gold mineralisation have been identified, initially on the basis of apparent breaks in strike continuity at surface and subsequently through confirmation of strike discontinuity or at least variation at depth. For convenience, these zones have been named, from west to east as Larjor, Latiff (discovered in 2010 in what had been assumed to be a gap), Kinjor and Marvoe.
Mineralisation Styles
The property hosts a typical Upper Archean to lower Proterozoic style of metallogeny, characteristic of greenstone-hosted lode gold mineralisation, where deposits are often referred to as orogenic, and characterised by the presence of gold-quartz veins and disseminated mineralisation. Gold mineralisation is hosted in moderate to steeply dipping quartz-dominated shear zones with associated extensional vein systems. This model is consistent with Archean orogenic gold deposits described by Hagemann and Cassidy (2000), Richards and Tosdal (2001), Goldfarb et al. (2001) and Roberts et al. (1989).