Minerals of South Africa

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This cover is postmarked on 08-06-1984 in Hotazel. It forms part of the Minerals of South Africa series, with the 11c, 20c, 25c and 30c stamps illustrating manganese, chromium, vanadium and titanium. Hotazel lies close to the Postmasburg and Kuruman manganese fields, which the info card notes hold roughly 81 percent of the world's proven metallurgical manganese reserves.

Description of the Cachet

A stylised map of South Africa fills most of the cover in a warm rust brown gradient. Four small gold circles mark mineral sites across the country, each labelled with a chemical symbol: Mn, Cr, V and Ti. A compass rose and the reference "4.8" sit near the bottom right. The postmark shows a simplified globe outline of South Africa above the town name Hotazel, tying the cover directly to the Northern Cape manganese fields described on the info card.

Information Card

STRATEGIESE MINERALE Suid-Afrika is een van die wêreld se belangrikste produsente van strategiese delfstowwe. 11c-seël Mangaan Mangaan is essensieel vir die vervaardiging van alle soorte staal — daar is eenvoudig geen plaasvervanger nie. Die hoofgebruik daarvan is om die smelte staal te suiwer terwyl dit eienskappe soos sterkte, taaiheid en hardheid daaraan verleen. Sowat 6,5 kg mangaan word gebruik vir elke ton staal wat vervaardig word. Suid-Afrika is 'n voorsiener van 'n indrukwekkende reeks mangaanertse waarvan een, psilomelaan, op die seël afgebeeld word. Byna al die land se metallurgiese mangaanertse kom uit die distrikte Postmasburg en Kuruman in die Noord-Kaap, waar reserwes van sowat 12 140 miljoen ton, of 81 % van die wêreld totaal, bewys is. 'n Gedeelte van die produksie word plaaslik verwerk vir ferromangaan gebruik. Suid-Afrika is die wêreld se grootste produsent van elektrolitiese mangaan en 'n belangrike produsent van hoëgraadse mangaandioksied, wat vir die vervaardiging van droë batterye nodig is. 20c-seël Chroom Chromiet, algemeen bekend as chroomerts, is die enigste noemenswaardige bron van chroom, 'n metaal wat geen plaasvervanger in die vervaardiging van vlekvrye staal het nie. Chroom is miskien beter bekend as die blink metaalbedekking op motorbuffers, deurhandvatsels, ens. Meer as 80 % van die wêreld se chromietreserwes word in die Bosveldkompleks van die Transvaal gevind waar dit tot op 'n diepte van slegs 300 m ontgin word. 'n Gedeelte van die Suid-Afrikaanse produksie word onverwerk uitgevoer terwyl die grootste gedeelte van die balans deur die plaaslike ferrochroombedryf gebruik word. Suid-Afrika se chromiet is ook besonder geskik vir dié kommoditeit se ander twee hoofgebruike, nl. die vervaardiging van vuurvaste stene en van natriumdichromaat, 'n nywerheidschemikalie. 25c-seël Vanadium Suid-Afrika is die wêreld se grootste produsent van vanadium en voorsien ongeveer 35 % van die wêreldmark. Die land se reserwes, geraam op 5,4 miljoen ton, is die grootste bekend en verteenwoordig 29 % van die wêreld totaal. Vanadium kom voor in die titaanhoudende magnetiet (op die seël afgebeeld) van die Transvaalse Bosveldkompleks. Vanadiumpentoksied word herwin deur die roostering en uitloging van die magnetietertsof deur die smelting om 'n slak te produseer wat die pentoksied bevat. Vanadium word hoofsaaklik as 'n legeerelement in die vervaardiging van spesiale hoëtreksterkte staal gebruik. Dit word ook as 'n katalisator in die chemiese bedryf en as 'n bestanddeel van verwe, medisyne, kleurstowwe, magnete en sweisstawe gebruik. 30c-seël Titaan Meer as 90 % van die titaan wat in die wêreld geproduseer word, word as titaanoksiede in die pigmentbedryf gebruik. Die res word as metaal in die vervaardiging van vliegtuie (meestal militêr) en duikbote gebruik. Met die inbedryfstelling van 'n aanleg in 1978 om titaanminerale uit kussandduine noord van Richardsbaai te herwin, het Suid-Afrika die wêreld se derde grootste produsent van hierdie kommoditeit geword. Die Richardsbaai-onderneming produseer rutiel (TiO₂) — uitgebeeld op die seël — wat as sodanig uitgevoer word, en titaanslak en yster deur die mineraal ilmeniet (FeTiO₃) te smelt. STRATEGIC MINERALS South Africa is one of the world's most important producers of strategic minerals. 11c stamp Manganese Manganese is essential for the production of all steels — there are simply no substitutes. Its principal use is to purify molten steel whilst imparting qualities of strength, toughness and hardness to it. About 6,5 kg of manganese ore is used for each ton of steel produced. South Africa is a supplier of an impressive range of manganese ores, one of which, psilomelane, is depicted on this stamp. Nearly all of the country's metallurgical manganese ores come from the Postmasburg and Kuruman districts in the Northern Cape, where reserves of some 12 140 million tons, or 81 % of the world total, have been proved. Part of the production is used locally for manufacturing ferromanganese. South Africa is the world's largest producer of electrolytic manganese and an important producer of high-grade manganese dioxide which is necessary for the manufacture of dry-cell batteries. 20c stamp Chromium Chromite, commonly referred to as chrome ore, is the only significant source of chromium, a metal that has no substitute in the production of stainless steel. Chromium is perhaps better known as the shiny metallic coating on car bumpers, door handles, etc. More than 80 % of the world's reserves of chromite is found in the Bushveld complex of the Transvaal, where about 2 400 million tons are estimated to be available to a depth of only 300 m. Part of the South African production is exported unprocessed while the greater part of the balance is used by the local ferrochromium industry. South Africa's chromite is also well suited to this commodity's other two major applications, viz. the manufacture of refractory bricks and of sodium dichromate, an industrial chemical. 25c stamp Vanadium South Africa is the world's largest producer of vanadium and supplies about 35 % of the world market. The country's reserves, estimated at 5,4 million tons, are the largest known and represent 29 % of the world total. Vanadium is found in the titaniferous magnetite (depicted on the stamp) of the Bushveld complex in the Transvaal. Vanadium pentoxide is recovered either by roasting and leaching the magnetite ore, or by melting it to produce a slag containing the pentoxide. Vanadium is used mainly as an alloying element in making special high-strength steels. It is also used as a catalyst in the chemical industry and as a constituent of paints, medicines, dyes, magnets and welding rods. 30c stamp Titanium More than 90 % of the titanium produced in the world is used as titanium oxides in the pigment industry. The rest is used as metal in the production of aircraft (mostly military) and submarines. With the establishment in 1978 of a plant to recover titanium minerals from coastal sand dunes north of Richards Bay, South Africa has become the world's third largest producer of this commodity. The Richards Bay undertaking produces rutile (TiO₂) — depicted on the stamp — which is exported as such, and titanium slag and iron by melting the ilmenite (FeTiO₃).

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