St John’s River South
Location and Access
St John’s River South (“SJRS”) is located in Nimba County, west of Tappita, a large township approximately 280km east of Monrovia.The main access route from Monrovia is 200km along the Yekepa Highway to Ganta and then 80km south along the Zwedru road to Tappita. From Tappita, a series of local roads and tracks provide access to various parts of the exploration licence (“EL”) area. SJRS covers an expanse of 221.52km2 and is dominated in the south by a low, broad, north-south trending range with a low relief, west-facing scarp. To the north east of SJRS there are a series of low, discontinuous and narrow ranges running east-west.
Rocks of the Kenema-Man domain are characterised by Precambrian assemblages of metasedimentary and meta-volcanic units perched as supracrustal remnant belts within a widespread basement of mostly leucocratic gneiss. The Pan-African orogeny (~570mya) resulted in the widespread deformation and structural modification of this Precambrian shield as well as the emplacement of various intrusive bodies. The geology of SJRS is characteristic of the Kenema-Man domain. The geological rock sequence within the SJRS tenement is that of sedimentary pile that, in general terms, grades upwards from mafic to felsic units with periodic iron formation (“IF”) deposition. The units are generally inter-bedded, often with no distinct boundaries. Units of IF are found within both amphibolite and psammitic units together with minor lenses of schist and gneiss. Friable IF units were found to be closely associated with the more psammitic metasediments and are often occupying topographic lows. Given the high proportion of alluvium across the tenement, friable IF is likely to be found below this cover if magnetic highs are present.
For the purposes of discussion, geological interpretation, and logistics, it is useful to separate the SJRS concession into the northeast domain and southwest domain separated by the midway road passing through Boyee village. The SJRS concession has been separated into the northeast domain and southwest domain along geological and logistical lines.
The northeast domain features a low disjointed range of hills trending east-north-east / west-south-west flanked on both sides by alluvial lowlands. Outcrop is typically poor, being either covered by alluvium or capped by laterite or scree of weathered iron remnants and consequently mapping relies significantly on scree which is taken to characterise underlying and/or adjacent rock types. Scree often occurs as large angular specimens suggesting proximity to source. Given the poor outcrop exposure, a high degree of interpretation was used. Interpretation of the field mapping and observation of meso-scale features suggests a series of recumbent, isoclinal folds with limbs dipping between 40o and 80o towards the south-south-east.
To the southwest of the Boyee village road, there is significant topographic relief and a marked change in the intensity of magnetic anomalies. The observed IF units may represent structural repetition due to multiple phases of isoclinal folding. Topographic relief is generally characterised by highs formed of harder mafic amphibolite and declines rapidly over boundaries with IF and felsic quartzite. The IF between the mafic and felsic units, and those wholly within the felsic unit, are more likely to be weathered and therefore more friable than those contained entirely within the mafic units.
The structural geology in this area is complex and difficult to interpret due to the dominantly sub-horizontal bedding and sudden differences in topographic elevation of up to 150m. Bedding consistently dips shallowly toward the south-south-east, and is parallel to the hinge of a large, recumbent anticline fold. Structural interpretation of this area is best discerned from the relative location of lithological units.
In 2009, BHP Billiton completed a short geological reconnaissance of various parts of the EL area. During late 2010 and through 2011, BHP Billiton undertook detailed geological ground mapping across the EL area. A total of 4 125 geology points were recorded throughout the mapping fieldwork, of which 337 were exposures of outcrop.
On request from BHP Billiton, West Africa Geo Services (“WAGS”) compiled a comprehensive mapping report including an updated version of the geology map of the southernmost portion of the EL. The mapping campaign was intended to investigate the mineral potential of this portion of the tenement which had not been covered by previous exploration due to poor access and limited time during the mapping seasons.
A total of 264 geological observation points were recorded including test pits and 11 test pits completed and 10 auger holes drilled. Rock chip samples were collected. 79 Of the 88 samples were analysed.
Significant outcrops of thinly banded, weakly magnetic iron formation were mapped throughout the area. These were also intersected by auguring and deep pitting. Lenses of dolerite and amphibolite could be seen cross-cutting the iron formation while metasediment underlain by granite gneiss defined the bedrock geology. Analysed samples showed moderate-grade ores ranging from 35-55% Fe. Direct shipping ore (“DSO”) potential exists in the caprock with average grades of 61.5% Fe with some silica content <2.2% and <3.2% aluminium, though further work is required to better understand the nature and extent of this material.
Work Program 2016/ 2017
The work program will comprise of the following:
- Further wide spaced reconnaissance drilling to determine the distribution and extent of potential mineralisation;
- Determination and delineation of the two best targets; and
- Selection of the best target for resource drilling and potential geology modelling.