The historic Aphae mine is located in the south-western part of South Korea, on the south eastern side of Aphae Island in the Jeolla-nam Province (Figure 1). The mine sits on a small scrub covered hill approximately 80m in diameter with a flooded 15m diameter historic open cut (see photo inset, Figure 2).
The Aphae epithermal gold-silver prospect has many similarities to the currently operating Eunsan-Moisan gold-silver mine to the south (Figure 1) with both having:
- a large weakly auriferous hydrothermal clay mining operation immediately to the east of an erosion-resistant hill; and
- been formed at the intersection of a set of conjugate structures providing mineralisation pathways and enrichment zones.
Historically, the Aphae gold deposit was discovered and mined during the late 1930’s and early 1940’s. The mine produced over 115 kg of gold over the 1940 to 1942 period from the shallow open cut (sometimes referred to in the industry as a “glory hole”) and an alluvial deposit adjacent to the pit was also exploited but historical production figures are unavailable. The open cut occupies the small Aphae hill and sits approximately 1.5 km north west from the Koryong clay mine which is still in operation.
A more modern operation was established in the late 1960’s with the development and commissioning of a small milling plant on the site. A small underground decline was developed with two small sublevels to 25 m below the surface. No production figures are available, and the timing of the mines closure is not clear in official Korean Mine reports but likely in the early 1970’s due to the low gold price.
The alluvial deposit was assessed by the Korean Government in the 1980’s who drilled much of the reclaimed area with 170 auger holes to an average depth of 14 m and identified a 0.3 m thick layer covering 12.6 hectares averaging 0.14 gm/cubic meters defining a small gold resource. The key outcome of this information is that it is unlikely that Aphae hill is the only source of the gold and that for such a relatively large alluvial gold field, a larger hidden gold-silver mineralisation body is likely to be in the area.
KORES did undertake two diamond drillholes in 1980 with one hole (DDH 80-1) 200 m deep. The peak intercept from this drilling was 0.5 m @ 7 g/t gold and 104 g/t silver from 170.8 m. The second hole DDH 80-2, intersected vein and breccia mineralisation but reported no significant intersections. The deposit has not been closed off in any direction or at depth. The results of this historical drilling are shown in the Table 2 at the end of this report extracted from the KORES drilling report.
Indochina Goldfields Ltd (Ivanhoe Mines) reviewed Aphae in 1995 with 6 rock chips sampled from the mine mullock heap with all samples returning >1.5 g/t gold and peak assays of 7.72 g/t Au and 55 g/t silver.
Figure 1: Location of Southern Gold’s current portfolio in South Korea. Project Generation activities, focusing in southern Korea, including the Jeolla District (left) and the Gyeongsang District (right) highlighted in green boxes.
Figure 2: Aphae, South Korea. Project detail illustrating open undefined mineralised system.
Table 1: Significant Assays (>1g/t Au or >70g/t Ag) from rock samples at Aphae, Muan 109 tenement.
- Table 2: Historical KORES government drilling from Aphae, 1980.
All interval widths are downhole widths, unless otherwise stated.
A full review of historical data will be completed including assessing the value of reprocessing the KORES government geophysical data and the two historic drillholes in the area.
Diamond drilling can then be planned utilising all available data to test the strike and down dip extent of the main Aphae mineralisation, which to date has had very limited exploration for a historically producing gold mine.
The Aphae target is easily accessible by road and a program will be planned to initially conduct detailed project-scale geo-structural mapping, collect additional rock chip sampling of the broader license area, and complete a small two-diamond hole programme to test under the existing open cut and the strike and down dip extent of the main Aphae mineralisation. This initial programme will be completed over the coming months.
The Aphae target is highly prospective as it sits within Cretaceous volcanic rocks of the Okcheon Fold Belt, which is the same host rocks as the nearby Eunsan-Moisan producing gold-silver mines to the south, and the Weolyu system to the north-east.
The mine area is inferred to consist of the eroded and exposed upper level breccia pipe and root vein system. The presence of intense acid leaching evident in granitic breccia clasts, coupled with kaolinite-dickite-alunite-anhedral pyrite alteration is indicative of high-sulfidation style epithermal mineralisation.
The south eastern coastline of Aphae Island is reclaimed coastland converted to agricultural use and much of the geology is unclear as no historical regional mapping exists. A coastal barrier wall marks the outer margin of the reclaimed area south of Aphae Hill.
Photo 1: Sample KRS203022 Hydrothermal breccia comprised of silica-sericite-clay altered rhyolite and granite, flooded by fine-grained anhedral pyrite & basemetal sulfides. 3.65 g/t Au, 23 g/t Ag, 9 ppm Cu, 1051 ppm Pb, 139 ppm Zn, 60 ppm As & 7 ppm Sb. Aphae Hill mullock heap.
Photo 2: Sample KRS203020 Grab sample of limonite-jarosite oxidised, silicified & sulfidic hydrothermal breccia mullock.: 6.08 g/t Au, 34 g/t Ag, 18 ppm Cu, 0.55% lead, 103 ppm Zn, 65 ppm As & 8 ppm Sb. Aphae Hill mullock heap.
The KORES report in 1970 described Aphae as a granite-hosted, milled and kaolinized hydrothermal breccia- and vein-hosted gold-silver and sulfide mineralised system the extent of which outcropped over one hundred lateral metres between workings and the sea over a width of 30 m and striking 010° NE with a steep dip of 80° to the southeast. Historic peak assays obtained consisted of 8.9 g/t gold and 155 g/t silver.
Southern Gold geologists are of the view that all historical work to date indicates only a small proportion of the mineralised system may have been assessed and that there is much more to be revealed on prospect scale.