Other Significant Mines
Northern Tenements – Pilgrim’s Rest Gold Field
Figure1: Northern Tenements
Vaalhoek Mine (Open cut)
Vaalhoek resource (0.62Mt @ 17.5g/t Au for 335koz, 82% Inferred), 20km north of the TGME Plant (Figure 1), represents mostly flat-lying reefs, are amenable to open-cut mining and is an example of the type of high-grade targets the Company is seeking to bring into production. This represents the highest grade open-pit resource in the portfolio, and thus is a priority for the Company to bring into reserves as soon as practical.
Beta Mine (Underground adit development)
Beta Mine was one of the first producing mines in the Pilgrim’s Rest area working almost uninterrupted until 1972. The fortunes of the mine varied between exceedingly rich, with grades of well over 31g/t near the outcrop, to a narrow pinching reef at deeper levels.
The Beta Reef is developed about 20 meters above the Beehive Chert and is well represented in the Pilgrim’s Rest area. It has been mined at Theta Hill and Browns Hill (DG4) but was very extensively mined at the Beta Mine, immediately west of the TGME Plant. It was last mined in 1971.
Recorded mining production at Beta was 818,000 tons of ore milled averaging 21g/t for 552,285 gold ounces.
The Beta Reef is conformable to the bedding, dipping at 5 to 7 degrees to the west and strike in a north/south direction. The underground average reef width was 24cm, comprising quartz and sulphides with imbricate staking of the reef giving rise to the thicker richer zones. The reef is locally high in copper and sulphur. At depth, the Beta Reef splits into three bands with the middle Beta Reef remaining the economic horizon. Stoping has taken place on a limited scale on the lower Beta Reef as evidenced on historical stoping plans from the mine.
Currently registered JORC Resource at Beta is 1.09Moz averaging 5.9g/t (46% Indicated, 54% Inferred).
Figure2: JORC Resource at Beta underground as at April 2018
Southern Tenements – Sabie Gold Fields
Figure3: Southern Tenements
Rietfontein Mine (Shallow underground adit development)
Figure4: Aerial view of Southern tenements, Rietfontein Mine looking North
The first underground project which may be developed is Rietfontein (Figure 2), subject to confirmation of reserves. The project is fully permitted so the main risks to the development timeline will be the completion of drilling and engineering work.
Currently Rietfontein has registered JORC Resource of 2.88Mt @ 8.42g/t Au for 780Koz (31% Indicated, 69% Inferred). (Figures 5,6)
Figure 5: JORC Resource at Rietfontein as at April 2018
Figure6: Resource/grade distribution at Rietfontein (cross section)
The mining permit issued in 2006 allows for the mining of Rietfontein and specifically by a mining right (MR358) registered with the Department of Mineral Resources. The mining permit is valid until 2028 with options to extend. This right allows for the construction of the surface infrastructure, rehabilitation of the adits, access to the underground workings, disposal of waste rock on the surface, and mining of ore.
The project also has a water user licence, which is valid for the duration of the project. The mining right includes phase two developments in the southern area of Rietfontein, where additional mining infrastructure is planned on surface.
Dewatering is under way at Rietfontein to enable construction of underground access adjacent to the old workings. Over 305ML has been removed during 2017/18 with very minimal usage of water pumps due to the high-low topography advantage, with the level dropping over 30m across the 3km of workings. This will facilitate underground drilling to upgrade the resources, ultimately towards reserve status.
Glynn’s Lydenburg shallow underground mine
The Glynn’s Lydenburg Mine operated over 55 years to 1958 and produced some 38 t of gold from 4.5 km strike and 500 m downdip underground workings on the Glynn’s Reef. Oxidisation mineralisation was encountered near surface, becoming refractory with depth. (Ward and Wilson, 1998) Glynn’s was the largest historical gold Mine in the region.
The current inferred resource at Glynn’s Lydenburg mine sits at 1.6 Moz Au @ 15.87 g/t with a stope grade of 5.19 g/t Au. (See JORC Tables)
The Glynns Mine is located near the town of Sabie in northeast South Africa. The area is well served by roads and infrastructure.
The mine sits in the stratigraphic succession of the Transvaal Supergroup, a regional sedimentary basin. The Transvaal group consists of, shales, sandstones, conglomerates and the carbonate units of the Malmani Subgroup, which regional is main gold host rock.
Epigenetic gold mineralisation in the Sabie-Pilgrims Rest Goldfield occurs as concordant and discordant (subvertical or cross) veins (or reefs) in a variety of host rocks within the Transvaal Basin. The Glynn’s Lydenburg mineralisation is flat reef system which been linked to emplacement of the Bushveld Complex.
Mineralisation at Glynn’s is stratabound occurs principally in concordant quartz-carbonate veins or reefs in flat, bedding parallel shears located mainly on shale partings within the Malmani Dolomites. These bodies are stratiform, and are generally stratabound. The reefs at Glynn Project Areas dip shallowly westwards at between 3° to 12°.
Figure7: Glynn’s 1.6Moz resource/grades
Figure8: Glynn’s historic underground workings near Sabie town
Figure9: Glynn’s historic underground workings and the Rietfontein UG mine orebody (3D).
Underground Mine JORC Resources Table
JORC Resources for Theta’s shallow underground mines including Frankfort, CDM, Vaalhoek (U/G), Glynn’s Lydenburg, Olifantsgeraamte, Ponieskrantz, Nestor, etc.
Figure10: JORC Resource table of the Company’s Underground Operations as at 1 May 2019