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Liberia

New Liberty Mine

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Overview

Mine TypeUnderground
StatusActive
Commodities
  • Gold
Mining Method
  • Sub-level stoping
  • Longitudinal stoping
  • Transverse stoping
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SnapshotThe New Liberty operation consists of two worked-out open pits, an underground mine with three separate portals and a large processing plant with tailings dams. All the ore mined in the region is processed through the New Liberty plant.

The mining is focused on the steeply dipping, deeper ore, under the worked-out open pits. This is extracted by underground operations, accessed by three portals (Larjor, Kinjor and Marvoe) developed into the sides of the open pits.

Avesoro Holdings Ltd., a private equity firm, acquired the mine in December 2018. Mine operations data has not been publicly available since then.
Related AssetNew Liberty Expansion Project

Owners

SourceSource
CompanyInterestOwnership
Government of Liberia 10 % Direct
MNG Group 90 % Indirect
Bea Mountain Mining Corp. 90 % Direct
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.

Contractors

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Deposit type

  • Orogenic
  • Vein / narrow vein

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).

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

CommodityUnits2023201820172016
Gold koz  ....  Subscribe1107664
All production numbers are expressed as metal in doré.

Operational metrics

Metrics2023201820172016
Plant annual capacity  ....  Subscribe1.1 Mt
Tonnes processed  ....  Subscribe1,411 kt1,144 kt842 kt
Stripping / waste ratio  ....  Subscribe16.1 11.1 9
Ore tonnes mined  ....  Subscribe1,352 kt1,166 kt996 kt
Waste OP  ....  Subscribe21,797 kt12,935 kt8,965 kt
Total tonnes mined  ....  Subscribe23,149 kt14,102 kt9,961 kt

Production Costs

CommodityUnits20182017
Cash costs (sold) Gold USD 862 / oz   918 / oz  
All-in sustaining costs (sold) Gold USD 1,120 / oz   1,427 / oz  

Operating Costs

Currency2017
OP mining costs ($/t mined) USD  ....  Subscribe

Financials

Units20182017
Revenue M USD 140.3   95.2  
After-tax Income M USD -40.3   -20.8  

Required Heavy Mobile Equipment

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AV - Autonomous

Personnel

Mine Management

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Aerial view:

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