Ngula 1 comprises an extensive 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 RC 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 7952m and 7623m respectively.
Along the principal set of workings, drillholes intersected mineralization under both a 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.
RC fence lines were planned to determine the presence of structures between these dominant areas of artisanal workings and one of these was completed. The fences are designed as holes are heel-toe drillholes and were aimed to the north approximately 40m apart and drilled to a depth of approximately 100m.
Due to the interpreted and intersected sub-vertical structures dipping steeply generally to the north, holes were drilled to the north and south to achieve intersection on both northern and southern interpreted structural zones with a broad zone approximately 200m wide. Drilling lines are spaced 100m apart, and a limited in-fill at 50m spacing has been completed.
The drilling to date has returned the following best results (shown below):
- TDD0004: 3.13g/t Au over 25.89m from 41.00m including 4.46g/t Au over 2.60m and 9.38g/t Au over 6.30m;
- TDD0005: 13.50g/t Au over 0.33m from 38.08m and 8.50g/t Au over 5.14m from 152.86m, including 58.49g/t Au over 0.68m;
- TDD0010: 3.72g/t Au over 2.50m from 189.00m including 6.44g/t Au over 1.20m;
- TDD0012: 8.6g/t Au over 0.98m from 171.92m;
- TDD0014: 2.50g/t Au over 1.50m from 87.00m including 3.50g/t Au over 1.00m;
- TDD0041: 22.81g/t Au over 15.00m from 299.00m including 34.58g/t Au over 9.70m, and 2.76g/t Au over 2.00m from 447.40m including 5.07g/t Au;
- TDD0049: 2.99g/t Au over 2.00m from 23.00m;
- TDD0051: 2.89g/t Au over 1.00m from 89.00m and 2.57g/t Au over 1.00m from 94.00m;
- TDD0053: 2.86g/t Au over 2.03m from 266.00m including 5.37g/t Au over 1.47m;
- TDD0054: 8.17g/t Au over 11.05m from 116.95m including 11.85g/t Au over 8.02m, 7.00g/t Au over 1.00m from 132.00m, 3.19g/t Au over 2.00m from 139.00m, and 4.53g/t Au over 2.00m from 149.93m;
- TDD0059: 5.93g/t Au over 0.64m from 142.33m and 3.72g/t Au over 0.61m from 310.99m;
- TDD0106: 5.09g/t Au over 2.77m from 285.42m including 11.70g/t Au over 0.98m;
- TDD0110: 4.22g/t Au over 5.00m from 195.00m including 6.58g/t Au over 3.00m;
- TDD0125: 19.03g/t Au over 0.94m from 35.16m including 26.40g/t Au over 0.66m, and 1.77g/t Au over 5.23m from 206.27m including 5.90g/t Au over 1.14m;
- TDD0126: 1.80g/t Au over 6.46m from 25.00m and 1.89g/t Au over 2.20m from 167.80m;
- TDD0136: 1.61g/t Au over 3.50m from 141.50m including 3.91g/t Au over 1.00m:
- TDD0145: 2.14g/t Au over 3.50m from 267.00m;
- TDD0146: 2.35g/t Au over 1.50m from 167.90m and 4.77g/t Au over 2.50m including 10.70g/t Au over 1.00m;
- TRC0001: 1.76g/t Au over 3.00m from 46.00m and 38.20g/t Au over 1.00m from 85.00m;
- TRC0002: 2.58g/t Au over 2.00m from 8.00m including 4.59g/t Au over 1.00m, and 3.77g/t Au over 1.00m from 54.00m;
- TRC0003: 3.76g/t Au over 2.00m from 21.00m, 28.57g/t Au over 3.00m from 54.00m, and 5.28g/t Au over 4.00m from 72.00m;
- TRC0006: 4.52g/t Au over 1.00m from 5.00m; and 3.16g/t Au over 3.00m from 206.00m including 4.41g/t Au over 2.00m;
- TRC0008: 5.18g/t Au over 1.00m from 9.00m and 3.75g/t Au over 6.00m from 35.00m;
- TRC0013: 17.23g/t Au over 4.00m, including 22.53g/t Au over 3.00m from 19.00m, 1.99g/t Au over 4.00m from 86.00m and 13.00g/t Au over 1.00m from 104m;
- TRC0014: 19.80g/t Au over 1.00m from 114.00m and 10.00g/t over 1.00m from 122.00m.
A complete list of assay results from Ngula 1 can be found here.
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 no host rocks, geological structure or mineralization can be observed in outcrop.
Completed drilling shows that the main east west trends appear to be semi-continuous shear zones that pinch and swell along strike 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.
The best gold mineralization to date has been in the areas close to the interpreted intersection points of these cross-shears and the main east-west shear zones. Some gold mineralization also appears concentrated in shear zones hosted by pillow basalts and in the thick, variable package of metabasalts and porphyritic meta-volcanic rocks.
Sulphide mineralization tends to be concentrated in larger shear zones, in quartz veins and in the heavily altered host rocks 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 chalcopyrite but these do not generally contain gold unless shear zones are developed in the vicinity.
Pyrrhotite is the dominant sulphide with lesser pyrite and chalcopyrite. It can be finely disseminated in the more intensely deformed zones of the shear zones, or can occur as coarse blebs, masses and bands associated with more siliceous and chloritised zones. Pyrrhotite associated with chalcopyrite can also be found concentrated along milky and smoky quartz vein margins, or as fine stringers or replacement blebs.
Alteration is predominantly chlorite-mica-amphibole, plus minus feldspar, and many of the highest gold values are found in shear zones associated with these alteration assemblages. Chaotic, apparently multi-phase mylonitic textures, often crosscut by several distinct sets of shear veins characterize the shear zones. Sulphide stringers are common and are frequently parallel or sub-parallel to the main shear fabric. Intersections of highly altered and sulphide mineralized shear zones that can be correlated with similar gold bearing structures along strike have been achieved that contain only very low quantities of gold.
Planned follow up RC drilling at Ngula 1 is required to delineate shallow open pittable resources along the 600m of strike and, in the future, deeper diamond drilling to delineate high grade mineralized shoots that could be exploited by underground mining methods.