An extensive area of east-west trending artisanal mining activity, including some hard rock mining through deep shafts and adjacent exploitation of colluvial material
Ngula 1 comprises a wide area of east-west trending artisanal mining activity, including some hard rock mining through deep shafts and adjacent exploitation of colluvial material. A secondary target area some 400m to the north is defined by anomalous gold in soil/RAB samples in historical exploration. The area is characterized by several east-west trending magnetic lineaments along which artisanal activity is focused, interpreted to be focussed on sub-vertical brittle ductile shears hosting quartz veins, sulphide mineralization and associated alteration with gold hosted within the veins and altered meta-basalt host rock.
Diamond and reverse circulation drilling has been aimed at testing the dominant structures being mined and test for similar hidden structures between these. To date thirty-five diamond and forty-one RC holes have been completed for this target, comprising 9107m and 7623m respectively.
Along the principal set of workings, drill holes intersected multiple structures hosting mineralization between and beneath a prominent northern and southern zone of artisanal workings at vertical depths down to 200m.
The program tested along a strike of 600m to determine the lateral extent of the mineralization. All these holes are drilled to a final down-hole depth of approximately 300m.
In order to achieve intersections on all structures, due to the the extent of surface workings and the interpreted sub-vertical to steep north dip of these structures, holes were drilled from the north and south on both northern and southern interpreted structural zones along broad 200m wide corridor. Drilling lines were spaced 100m apart, with a limited number of in-fill drillholes at 50m spacing also completed.
A recent preliminary wireframe modeling exercise has defined at least 6 sub-parallel north dipping structures, each of which has returned one or more significant intersections. A number of these results are exceptional and follow-up drilling will endeavour to define the extent of high grade zones along strike and dip with the aim to extend the drilling and define resources.
NGULA 1 TARGET DRILLING HIGHLIGHTS
|Grade Au (g/t)
|Depth From (m)
Footnote: All widths are borehole intersection widths and true widths have not been determined
The geology comprises predominantly mafic meta-volcanic rocks, with thin intercalated meta-sedimentary units within the meta-volcanic pile. There is no surface expression of the geology other than ruddy ferruginous soils, the weathering products of the mafic meta-volcanic rocks and there is no outcrop to reveal host rocks, geological structure or mineralization.
Completed drilling shows that the main east west trends appear to comprise multiple semi-continuous shear zones that are interpreted to pinch and swell along strike and up and down dip and dip steeply (80-90°) to the north. These shear zones are possibly linked by steeply dipping cross-shears trending either northeast-southwest or northwest-southeast at varying dips, and which are considered important controls on pinching and swelling as well as tenor of gold mineralization.
Mineralization consists of sulphides concentrated in shear zones, with accompanying quartz veins and alteration of sheared anf fractured host rocks within and adjacent adjacent to these structures. Small quartz veinlets can also contain appreciable amounts of sulphide away from areas where observable shearing has occurred. The margins of basaltic pillow lavas commonly host abundant pyrrhotite, pyrite and minor chalcopyrite but these do not generally contain gold unless associated within or adjacent to shear zones.
Pyrrhotite is the dominant sulphide with lesser finely disseminated pyrite and chalcopyrite. Sulphide also occurs as coarse blebs, masses and bands associated with more siliceous and chloritised zones within the shears. Pyrrhotite associated with chalcopyrite can also be found concentrated along milky and smoky quartz vein margins, or as fine stringers or replacement blebs.
Diamond and RC drilling has been aimed at testing the dominant structures being mined and test for similar hidden structures between these. To date 58 diamond and 41 RC holes have been completed, comprising 12,693m and 7,623m respectively.
The planned drilling at Ngula 1 will accurately define the structural controls on mineralization and commence the delineation of shallow low grade resources, and deeper diamond drilling will follow the structural trends up and down plunge to define the extent of previously intersected high grade mineralization and the potential of these shoots to host open pit and underground exploitable resources.