Exploration and Development
The Company’s proposed strategy for the Gum Creek Gold Project comprises three key objectives:
- undertake extensional and infill drilling to grow the known resources and lift defined resources into higher-confidence JORC categories;
- undertake regional exploration targeting new gold discoveries outside of the known resources; and
- carry out development studies (including but not limited to metallurgical and processing investigations) on the free milling and refractory mineralisation.
High-Grade Mineralisation Intersected at Premium-Butcherbird Prospect
- A first pass, twelve-hole diamond drill program to test the Butcherbird Shear and Swan Premium Lode intersected high-grade gold mineralisation, 5.0m @ 10.6g/t Au from 257.0m in SBDD073;
- Results received from first four holes, with assays from remaining eight holes expected in September; and
- A single diamond drill hole to test previously reported broad Volcanic-Hosted Massive Sulphide (VHMS) style copper mineralisation intersected semi massive sulphide mineralisation at the Altair Prospect. Assay results pending.
On 17 September 2018 the Company provided an update on its recent exploration activities [here]. Activities reported included:
- Diamond drilling at the Butcherbird Shear and Swan Premium Lode Exploration Targets, including initial gold assay results from the first four diamond holes of an initial twelve-hole program;
- Air-core (AC) assay results for Wahoo East and Toedter West; and
- Diamond drilling at the Altair Copper Prospect.
Premium Lode and Butcherbird Shear
As reported in the Company’s Announcement dated 7 July 2018, Horizon recently undertook a reinterpretation of the geological controls on high-grade gold mineralisation in the Premium Lode and Butcherbird Shear at the northern end of the Swan system. This reinterpretation highlighted the potential to significantly increase the underground Mineral Resources in this area with additional exploration drilling.
Following the geological reinterpretation, the Company estimated Exploration Targets of between 30,000oz to 100,000oz contained gold for the Premium Lode and 270,000oz to 800,000oz contained gold for the Butcherbird Shear.
An initial diamond drill program of 12 holes totalling 4,897 drill metres on the Premium Lode and Butcherbird Shear Exploration Targets commenced in late June 2018 and was completed on 22 August 2018. The aim of the program was to assess the validity of the Exploration Targets by drilling a broad spread of holes to test and support the predicted thickness and grade of the models in those areas.
Figure 1: Long section looking west showing historical and new drill hole pierce points testing the Butcherbird Shear and Premium Lode.
Figure 2: Cross section 6983780N looking north showing historical and new drilling intercepts on the Butcherbird Shear and Premium Lode
Zones of quartz flooding with minor sulphide mineralisation were intersected at the anticipated target depth in most holes. True widths of the quartz flood zones intersected in the current program are estimated to be up to 5 metres. Figure 3 shows the mineralised quartz flooding intersected in hole SBDD073.
In addition to the intercepts interpreted to be on the Butcherbird Shear, several other unexpected quartz-sulphide structures were intersected. At this stage the Company is unable to correlate these structures with the known lodes and is therefore uncertain of their economic significance.
Gold assay results for the first four holes (SBDD071, 072, 073 and 074) have been received. Better assay results include:
- 4.0m @ 2.6g/t Au from 297.0m in SBDD071
- 5.0m @ 10.6g/t Au from 257.0m in SBDD073
Logging and sampling of the remaining holes are in progress, with assay results expected in September 2018. Once all results are available the Company will provide a further update, including a discussion of any material changes to potential scale or quality of the Exploration Targets resulting from the exploration activities.
Figure 3: Photograph of mineralisation in hole SBDD073 with individual 1 metre gold assays shown in red.
Toedter West Air-core Drilling
Air-core drilling of the Toedter West and Wahoo East prospect areas was completed in late July 2018 and assay results have now been received.
Toedter West is a series of small coincident magnetic and electromagnetic geophysical targets over a strike length of 6km. These targets were interpreted by the Company to be possible sulphide-bearing banded iron formations (BIFs) prospective for gold mineralisation. A single reverse circulation (RC) hole (GWRC482) drilled at Toedter West by the Company in 2017 intersected 1m @ 20.6g/t Au from 133m. At the eastern end of the target is the Toedter prospect, which has an existing Mineral Resource of 34,200oz.
A total of 87 holes for 2,775 drill metres was completed at Toedter West in the current program. Four-metre composite samples were submitted for analysis by fire assay using 30g charge. Best assay results from the Toedter West program include:
- 3.0m @ 0.71g/t Au from 76m in GPAC1353.
Drill hole traverse locations are shown in Figure 4.
Whilst the initial results have not met the Company’s expectations, it should be noted that only a limited extent of the 6km strike length of the target have been tested. A further refinement of the targeting criteria is now recommended.
Figure 4: Plan of Toedter West Prospect showing air-core drilling traverses on coloured EM conductivity and greyscale magnetics
Wahoo East Air-core Drilling
The Wahoo East prospect is interpreted from magnetics as an untested shear zone that has been intruded by a late granitic body. A total of 74 drill holes for 3,711 drill metres tested this target. Four-metre composite samples were submitted for analysis by fire assay using 30g charge. No significant results were returned from Wahoo East, and no further work is planned at this time.
Drill hole traverse locations are shown in Figure 5.
Figure 5: Plan of Wahoo East Prospect showing AC drilling traverses on coloured TMI magnetics
Altair Copper Prospect
The Altair Copper Prospect is interpreted to be Volcanic-Hosted Massive Sulphide (VHMS) style copper mineralisation associated with black shales and intermediate volcanics (Figure 6). Drilling in the 1990’s by previous explorers intersected broad zones of copper mineralisation, including the following assay results:
- 44m @ 1.2% Cu from 56m (ALAC005);
- 24m @ 1.0% Cu from 64m (ALRC007);
- 20m @ 1.1% Cu from 52m (ALRC002); and
- 20m @ 0.9% Cu from 64m (ALRC006).
Figure 6: Altair Copper Prospect drill-hole location plan showing significant copper intercepts in historical drilling, plus location of Horizon drill-hole ALDD002
A single deep diamond hole commenced on 14 August 2018 and was completed on 19 August 2018 at a final depth of 370.1m. The hole intersected an upper sequence of disseminated and semi-massive pyrite-rich black shales to a depth of 239m, followed by intermediate volcanics with extensive thin semi-massive to massive pyritic bands to the end-of-hole. Assays are expected in September 2018.