DIAMONDS – OENA
LOCATION
The Oena Project (the “Property”) consists of one New Order Mining Lease located in the Northern Cape Province, Republic of South Africa. Oena is 8,800 hectares in size and covers a 4.8 kilometre (“km”) wide strip along a 15 km length of the lower Orange River.
OWNERSHIP
Southstone Minerals Ltd owns 43% of African Star Minerals (Pty) Limited (“ASM”) which owns 100% of the Property.
Southstone Minerals Ltd subsidiary, ASM received confirmation from the Department of Mineral Resources that the mining right for the Property was renewed for a further period of nine (9) years to 15 March 2027. The renewal was granted in terms of the applicable sections of the Mineral and Petroleum Resources Development Act (Act 28, 2002).
GEOLOGY AND DEPOSIT TYPE
Oena, a producing alluvial diamond property, is located within a well established alluvial diamond mining province 50 km upstream of Namdeb’s Auchas and Daberas alluvial diamond mines, located on the Namibian or north bank of the Orange River, and 15 km and 60 km upstream of Trans Hex’s Reuning and Baken alluvial diamond mines, respectively, located on the South African or south bank of the Orange River.
Two separate and distinctly different aged diamondiferous bearing paleochannel gravels are present on the Property and have been named as follows:
- Proto‐terraces (dated as Miocene and 17 – 19 mybp in age) are higher‐level and are located greater than 40 metres (“m”) above the current Orange River level.
- Meso‐terraces (dated as Pliocece and Pleistocene and are 2 – 5 mybp in age) which are lower‐level and are located between 10 m to 12 m above the current Orange River level.There are five meso‐terraces on the Property including the Oena, Sandberg, Blokwerf, Fishriver and Kabies Sections. Most of the historical exploration has been concentrated on the Oena and Sandberg Sections and none has been completed at the Fishriver and Kabies Sections.
HISTORICAL MINING ACTIVITIES
The Property has seen various forms of exploration and mining activities that started in 1992 with work by independent mining companies who mined the proto‐terraces at the Oena Section until 1995, producing some 30,000 carats with an average stone size of 2 carats. The largest stone recovered was 79 carats.
Between 1995 and 2000 various contractors were employed to test mine the Property. Small pits, trenches and bulk sample pits were excavated and treated through a conventional pan plant. The results of this test mining are not known.
Between 2000 and January 2006 systematic drilling was focused on the meso‐terraces and a bulk-sampling program.
Between February 2006 and August 2007 trial mining was performed with results documented in daily mining and plant treatment reports. These results were used to measure average diamond sizes and expected grades in basal and suspended gravels over the Oena meso‐terraces. These verifiable results have been used to estimate average grades for the gravel remaining at Oena. The systematic drilling results have been used in sections and volumes of gravel, both suspended and basal have been estimated using a polygonal block method.
SOUTHSTONE MINERALS LTD RESOURCE REPORT
A National Instrument (“NI”) 43-101 report, dated and effective 31 October 2014, by Peter W.A. Walker B.Sc. (Hons.) MBA Pr.Sci.Nat. F.S.E.G. of VP3 GeoServices (Pty) Ltd has been prepared for Oena. The report records a historically estimated Inferred Resource within the six remaining blocks in the Oena Section.
Table 1: Oena Inferred Resource
| Volume cubic meters (m3) |
Grad | |
| Oena Section blocks | 1,075,000 ( ~2,795,000 tonnes) |
0.295 carats/100m3 (~0,12 cpht) |
In addition to this historical Inferred Resource, systematic Reverse Circulation drilling of the Sandberg terrace was completed and has shown an estimated 4.5 to 5.75 million cubic metres (~14 million tons) of basal and suspended gravel is present and was shown by two bulk samples to be diamondiferous, however, these sample volumes are too small to estimate diamond grades at a sufficiently predictable level of accuracy; please note that although the Sandberg gravels are expected to yield similar grades to the Oena section gravels, further bulk sampling may not result in the target being defined as a Mineral Resource. The potential quantity and grade are conceptual in nature. There has been insufficient exploration to define a mineral resource.
It is uncertain if further exploration will result in the target being delineated as a mineral resource. The Blokwerf, Visrivier and Kabies terraces require systematic drilling to estimate the total volume of gravels on the Property although historical small-scale sampling has shown them to be diamondiferous; again, further bulk sampling may not result in these targets being defined as Mineral Resources.
OPERATIONS
SOUTHSTONE MINERALS LTD – AFRICAN STAR MINERALS
Oena consists of an 8,800-hectare mining right located along the Orange River (Figure 1). Oena is owned by African Star Minerals (ASM) of which 43% is owned by Southstone.