KAROUNI (TROY 100% THROUGH TROY RESOURCES GUYANA INC.)
During the year, Troy’s exploration focus returned to brownfields and greenfields exploration. Initially a target review and target ranking process was exercised and an evaluation of historic data and maps was completed.
With the ore grade intercepts from Goldstar achieved in 2017 and the promising Auger results from Gem Creek, the entire Goldstar – Gem Creek and Upper Itaki corridor provides potential for the discovery of primary gold mineralisation. With confirmed similar geological and structural settings to the Smarts and Hicks deposits, the Goldstar and Gem Creek exploration work has the potential to yield significant exploration success.
In addition, a new land package at Ohio Creek was purchased in late 2018. Ohio Creek covers a part of the Tallman structure which continues to the NW and joins with the Gem Creek structure near the Upper Itaki Prospect. (Refer to the ASX Announcement of 12 September 2018 titled “Acquisition of Ohio Creek Prospect - Guyana”)
The exploration program at Ohio Creek was very successful during the year, intersecting high grade gold mineralisation at shallow depths. More than 50% of the holes drilled during the year intercepted gold mineralisation, with some of the assays returning very high gold values. This resulted in a further exploration ramp up during the year with the main focus being exploration, infill and resource drilling at Ohio Creek.
Other work during the year included auger soil sampling and mapping at Gem Creek, mapping at the Mirror Prospect and reconnaissance work at the Upper Itaki and Kaburi Hills Prospects.
Work was also undertaken to complete the near mine exploration at Spearpoint and Larken. Additional drilling at the Hicks 1 Extension commenced during the year with the objective of extending the near surface resource over the known Smarts Hicks shear.
NEAR MINE DRILLING
The geological model for Spearpoint was completed during the year. The geology at Spearpoint is similar to that at the Smarts deposit. The gold assays are related to N-S quartz veins in a coarse mafic unit adjacent to the shear zones. The majority of the high grade gold intercepts are situated between the hanging and the footwall shear. In the central part, the mafic unit is either repeating or might overturn and form a flat dipping “pipe” with a plunge to SE. A block and resource model was established for the prospect.
Early in the year, 20 RC drill holes for a total of 1,227 metres completed an infill drilling program at Larken. All assay results have been reported. (Refer to the ASX Announcement of 11 September 2018 titled “Exploration Results – Larken Prospect”)
The geology at Larken is simple with gold mineralisation related to a weak shear/contact zone between a sedimentary unit and basalt. A fair amount of massive quartz is common in the shear zone. A geological model for Larken was completed and an updated resource model and block model was established.
For both Spearpoint and Larken, a JORC compliant Measured and Indicated Resource block model has been created and a resource update was reported to the stock market. (Refer to the ASX Announcement of 19 September 2018 titled “Mineral Resources and Ore Reserve Statement”).
Hicks 1 Extension
Towards the end of the year, drilling to the NW of Hicks 1 pit commenced with the intention of extending the mineral resources along the known Smarts Hicks shear. Earlier exploration drilling had identified smaller mineralised felsic porphyry rocks in the Hick 1 Extension. Felsic porphyries are the main host rock at Hicks. Due to their discrete strike extension, areas between the current wide drill spacing towards the NW of Hicks 1 was seen as having potential for such small porphyry intrusions.
The infill drilling was planned on a nominal 20 x 15 metre grid spacing for 57 RC drill holes for a total of 1,700 metres. The holes were drilled to shallow depths of between 20 and 70 metres for a fast track, short term ore delivery to the Karouni Mill. Drilling was oriented towards NE and completed for 38 RC holes for a total of 1,129 metres.
Exploration Target Review
The first step in the re-start of regional exploration was a targeting exercise. The review was based on structural settings from geomagnetic maps, geological settings from mapping/historic maps, stratigraphy from drill data, pXRF geochemical data from auger/soil sampling, mineralisation style and assay intercepts. Economic factors like distance to the mill were included, but with a low priority. The highest priority was on existing high Au intercepts, strong structural settings, like major NW corridors with cross cutting early EW structures and pXRF anomalies of chrome, titanium, iron and arsenic. Alluvial workings and drainage was also used to identify sources of gold mineralisation. Historic and recent saprolite workings have been mapped and interpreted as in situ gold occurrence. An updated exploration target pipeline has been created.
Greenfield exploration work over the past year has covered all priority targets, including Gem Creek, Upper Itaki and Kaburi Hills. For some targets, only reconnaissance work was completed and for others additional mapping and Auger sampling completed.
Gem Creek Prospect
The Gem Creek targets have seen an intensive mapping and sampling program during the year. The mapping has identified interesting features such as a shear zone with quartz veining, a massive felsic intrusive unit with intensive quartz stockworks and coarse gold in stream sediment test sampling.
A gridded hand auger program in the Gem Creek and NW Gem Creek Prospects with nominal sample points of 400 by 40 metre and line orientation of azimuth 45 degrees was completed. The program sampled the approximately 0.3 to 1 metre horizon below the surface. All samples have been scanned with the pXRF and assayed for gold by fire assay with AAS finish.
The pXRF sampling highlighted the continuation of the Goldstar high chrome corridor – also the gold favourable lithology in Smarts – for at least 1,200 metres strike extension.
Anomalous results for arsenic, iron and titanium have been mapped. High readings of titanium and iron are a signature for mafic rocks and higher arsenic values may be related to intrusives.
The structural setting of the NNW trending Goldstar – Gem Creek structure is intersecting an early EW structure and likely to create a dilatational jog and emplacement of porphyry intrusives. As well as the lidar signature, airborne magnetics support this interpretation of a near circular feature. Lidar is geographic survey system providing accurate surface details and structural information.
The NE part of the prospect is covered by a 1 to 3 metres thick laterite/duricrust cap and no sampling was possible.
First pass RC drilling program has been planned.
The first reconnaissance mapping at Upper Itaki confirmed the occurrence of mafic rocks and the existence of the south-western and north-eastern granitic intrusives. Therefore the conceptual model is proven with further field mapping and sampling to be carried out. The mafic units are likely to be a basalt or andesite which is a package of the lower volcanic sequence – the same stratigraphic settings in which Smarts and Hicks are located. During reconnaissance work it was noticed that the area was covered partly by thick duricrust and partly by sand. A soil sampling and/or a scout drilling program is planned to penetrate through the cover. Reconnaissance work has found creek areas which have been historically intensively mined down to the saprolite and beyond.
Review of historic data added another greenfield target to the portfolio. Kaburi Hills is located in a highly prospective area for gold mineralisation about 8 kilometres north of the famous Omai Mine (which is not owned by the Company). Historical maps show high gold concentration in stream sediment samples and alluvial workings. Airborne magnetic maps and structural interpretation shows several flatter WNW structures similar to those at Omai, Honey Camp and Ohio Creek.
The first reconnaissance mapping at Kaburi Hills confirmed the northern parts are covered by sand with saprolite along river valleys. To the south, weathered sedimentary rocks with relict pyrite have been found. More detailed mapping and auger sampling is planned in an attempt to prove up several conceptual targets within the prospect area.
Ohio Creek Prospect
Ohio Creek is located within the north eastern sector of Troy’s tenement holdings in the close vicinity of several other highly prospective and underexplored targets including Gem Creek, Goldstar and Upper Itaki, each of which is located only approximately 10 kilometres from the Karouni processing facility. The Ohio Creek claims were acquired by Troy in August 2018.
Initial work encompassed mapping of the Ohio Creek tenements and Tallman Pit. The mapping of the Tallman Pit identified a sheared contact between the carbonaceous sediments and folded andesite. Along this contact several flat dipping narrow quartz veins with visible gold have been recognised.
Following the mapping, a fist pass RC drilling program (Phase 1) for an initial 39 RC holes was drilled. This initial drilling campaign was very successful including a record drill intercept of 1 metre at 251.27 g/t Au. The Phase 1 drilling was followed by RC drilling for infill, step out and resource calculation purposes.
During the year, a total of 169 RC drill holes were completed for a total of 15,661 metres.
The Ohio Creek mineralisation was tested and confirmed over about 950m of strike extension, but occurs in several spots due to step over and folding. The whole drill tested corridor comprises about 2,000 metres of strike with two additional zones to the NW with patchy mineralisation.
Late in the year, diamond drilling was used to identify structural settings, geology and test the deeper potential at Ohio Creek. A total of 11 diamond drill holes for a total of 2,518.4 metres were drilled.
The geology at Ohio Creek is complex and strongly folded. The Tallman shear zone develops on the contact between moderately deformed andesite and strongly deformed interbedded shale/siltstone. Within the black shale/siltstone package, porphyritic felsic volcanic, irregularly beds of chert and conglomerates occur. In the hanging and footwall of the above described central zone, massive fine to medium grained basalt was mapped. Towards the SE the andesite is more strongly foliated. Towards the NE, a second sediment package of chert has also been drilled. Additionally, several foliated, parallel of medium to coarse grained dolerites have been logged.
The Tallman shear zone consist of multiple shears primary developed within the shale/siltstone unit and is focused in the graphitic shales. The andesite is sheared only along the contact to the black shale/siltstone. The shear zone is typically marked by an abundance of quartz-calcite veins. All lithologies at Ohio Creek are strong deformed by at least two deformation events. The S0 and S1 foliation is the primary fabric and strikes NW-SE. The second deformation D2 forms WNW oriented S2 foliation and F2 folds.
The main mineralisation is located in narrow (5 to 25 centimetres) NW striking and shallow dipping massive quartz veins. The veins are composed of quartz calcite and the gold is native in coarse 1 to 5 millimetres grains along the margin of such veins.
A total of six trenches have been dug in the central Ohio Creek area. Vertical channels over flat dipping quartz veins with visible gold returned some very high grade gold assays with the max of 1 metre @ 564.45 g/t Au perpendicular over a 25 centimetres wide vein.
RC drilling to the south east intersected mineralisation in two holes – one up dip and one down dip. The mineralisation is interpreted to be either an offset from the main mineralisation to the SW or, more likely, a second zone of mineralisation. Additional drilling is underway to confirm.
The construction of a satellite camp at Ohio Creek has been completed. The camp has accommodation for around 34 persons, with the opportunity to add more accommodation blocks whenever needed. Kitchen and washroom facilities can service up to 50 persons.
Construction of an access and haul road to Ohio Creek is ongoing. The new road is being routed via the Goldstar Prospect in an almost straight line. The road has been strategically located to cater for any potential new mines at Goldstar or Gem Creek as well as Ohio Creek.