Stavoren-Mute Fides, Marble Hall, Ephraim Mogale Local Municipality, Sekhukhune District Municipality, Limpopo, South Africai

Regional Level Types
Stavoren-Mute Fides	Mining Field
Marble Hall	Town
Ephraim Mogale Local Municipality	Municipality
Sekhukhune District Municipality	Municipality
Limpopo	Province
South Africa	Country

STAVOREN - MUTUE FIDES

The farm of Stavoren 676 KS is located within the administrative boundary of the recently redefined Limpopo Province about 170 km from Pretoria, South Africa. The Stavoren - Mutue Fides tinfield is in a broad area approximately 30 km north of Marble Hall and geologically falls within the Stavoren fragment of the Stavoren Granophyre sheet of the Bushveld Complex. The fragment consists of three lithostratigraphic units, i.e. Rooiberg Group felsite, Makeckaan Quartzite Formation and the Stavoren Granophyre.

Cassiterite deposits are relatively widespread in the felsic rocks of the Bushveld Complex, particularly associated with the Lebowa Granite Suite and the Rashoop Granophyre Suite. Three main types of tin deposits occur; mineralization in the Transvaal Supergroup sedimentary strata, such as the Rooiberg tin fields, deposits in the granite per se, e.g., at Zaaiplaats, and those in granophyre at Stavoren. The Mutue Fides – Stavoren tinfield is located in the south-eastern Waterberg, 80-85 km south-southeast of Makopane on the farms Mutue Fides 648 KS and Stavoren 676 KS respectively and form part of the Olifants tinfield. The micromineral specimens featured were all collected in the southerly located Stavoren deposits.

Specific Sites

The cassiterite deposits are hosted by pipe-like bodies or pockets of pegmatite with intersecting veins and fractures along which mineralization took place. About 60 ore occurrences at Stavoren - Mutue Fides tinfields are reviewed in extensive detail by Wagner (1921) from which 37 mineral species have been identified. The primary ore mineralogy of cassiterite, scheelite molybdenite, chalcopyrite, pyrite, arsenopyrite, galena, sphalerite, bismuthinite and galenobismuthinite is associated with gangue minerals quartz, sericite, feldspar, chlorite, fluorite, calcite, apatite and tourmaline. Secondary minerals of copper, tungsten, bismuth and lead had been also reported.

The so-called A Group deposits were discovered in 1912 in granophyres but were soon abandoned as were the Camp Line Workings. From an economic standpoint the B Line Workings were the most important. Wagner (1921) describes more than fifty deposits that were at one stage or another worked for tin and tungsten. These were grouped together into the following locations;

A Group
B Line
“C” Line
“D” Pipe
Camp Line
Auret’s Baby – Hillside Quarry group
Morning Sun Area
The 71 Yards Fissure

Of these, the B Line workings were economically the most important. Steyn (1962 p. 11) subsequently further divided the deposits naming each mineralized pipe. The pipes are characteristically steeply dipping towards the north. The largest deposit is 10 m diameter on surface and was exposed down to 100 m below surface. It is important to note that the pipes and /or fissures are not mineralized throughout but have discrete ore bodies that occur as irregularly shaped pods within the host rock of altered granophyres. The B Line working consisted of multiple, scattered dumps interspersed between long abandoned and derelict buildings. There is a decline adit extending eastwards into the sloping granophyre hillside. The highest concentration of dumps is in the B Line workings vicinity and it is expected that these would yield large amounts of micromineral specimens yet these are neither plentiful nor common here. The most productive site for microminerals of all the Stavoren deposits today is the Hillside Quarry which is reached by driving north / northwest along a track for approximately a kilometre from the B Line deposits. One of the larger and deeper excavations is at Hillside quarry, with spoil piles encircling the surrounding bush and spilling down the slope.

Examination of dump material shows pegmatitic debris with quartz crystals up to 15 cm often cemented by coarse grained, red orthoclase feldspar. The rubble also consists of blocks of massive fluorite ore and associated host granophyres. Some of this material appears to have been produced from the gossan as goethite stains the rocks and, in general, there are many small cavities and vugs lined by the esoteric array of micromount minerals. Even today, almost 100 years after mining commenced at Stavoren, the dumps still yield interesting and rare micromineral specimens.

A comparison of the dump material from the B Line workings, Hillside Quarry and the more northerly located Spruit and Western Quarry workings reveal an apparent subtle difference in the host rock geology. Spruit dumps are more orthoclase-rich and there appears to be more vein quartz associated with this site relative to others.

The microminerals featured here come from nine sub-localities within the Stavoren collecting site, mostly the old diggings, mine trenches and old dump sites. Many interesting specimens were also collected from the general Stavoren area that includes the grounds between the specific sites. Some collecting localities were discovered by members of SAMS and are named by the micromounters i.e. Mimetite site and Reservoir site. A long list of minerals from Stavoren already exists and to this list we add some of the rarest copper, iron and bismuth arsenates, carbonates and other species described in the following pages. Ninety three minerals were identified in this study with thirty five new contributions to the site list of which, to our knowledge, seventeen are first reported occurrences for Stavoren, the Bushveld Complex and South Africa in general.
(Extract from Atansova, Cairncross and Windisch, 2016).

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