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Mon, May 25, 2015

Summary of Economic Geology of Provinces: Mpumalanga Province

The map below is a low resolution image for a much larger map (scale 1:750 000), of which an extract is shown below in more detail, and is accompanied by a description of the general economic geology of the province. An example of such detail is shown below. This map can be purchased from the Council for Geoscience. Please contact Mashudu Matshivha to place an order.

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Mpumalanga Province: Nelspruit: detailed

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A summarised mineral profile of the Mpumalanga Province
By JHW Ward, Council for Geoscience

INTRODUCTION

 

According to Minerals Bureau statistics, mineral production sales for Mpumalanga Province during 1994 totalled R 9 280 million (R 19 295 million in 2000) of which precious metals accounted for R 1 305 million, base metals amounted to R 143 million, and coal accounted for R 7 644 million. Sales of industrial minerals and miscellaneous production amounted to R 189 million.

 

PRECIOUS METALS

 

Extensions to the Witwatersrand basin underlie the southwest portion of Mpumalanga. These include the dormant South Rand goldfield and the producing Evander goldfield. From 1958 to date, the latter has yielded over 1000 t of gold from four mines - Bracken, Leslie, Kinross and Winkelhaak. The increased tempo of exploration for gold in South Africa during the 1980s will have included a re-assessment of the South Rand and Evander goldfields, but no significant discovery leading to the potential development of new gold mining projects in these goldfields has been announced by the mining houses involved. Mineral rights in the area with any potential for gold of economic interest will be securely held by the mining companies which have vested interests in these goldfields.

 

The search for small additional reserves of gold in Mpumalanga Province will include a re-examination of deposits in the Transvaal Drakensberg and Barberton goldfields. In the former case, Transvaal Gold Mining Estates (Randgold) holds the mineral rights for the majority of the significant former gold producers in the goldfield, and have recently sold 51% of the holdings to an Australian mining house, Beachcove. In the case of the Barberton goldfield, the mineral rights to significant former, present or potential gold producers are mainly held by South African mining houses. In addition to the mineral rights being tightly controlled, the oxidised or non-refractory gold ore has long since been exploited. What may remain in some former gold workings is refractory ore that, following some form of tribute agreement with the mineral rights holder, could be mined, milled and concentrated for sale, at a modest profit, to a beneficiation plant capable of extracting gold from refractory concentrates.

 

Intensive exploration of the Critical zone of the Bushveld Complex is underway on the eastern limbs of the Complex lying within Mpumalanga. Within the next few years significant Platinum Group Metals (PGM) mines will be operating within the province, exploiting the UG2 in most cases. There is significant potential for further exploration, particularly in the area south of Groblersdal. Platinum group metals have been produced as a by-product from the Nkomati nickel mine since 1997.

 

BASE METALS

 

Mpumalanga Province includes important ferrochrome, ferromanganese, ferrosilicon, and ferrovanadium production facilities. Some of the feedstock for these metallurgical plants is mined from silica, chromite and vanadiferous magnetite deposits in the Steelpoort area. The scope for down-scaling these operations to the level of small mining is minimal, and SMME development might be better focused on the provision of services to the ferroalloy producers in the area. The commissioning of the comparatively low-grade Nkomati PGE-nickel mine west of Barberton has been a boost to base metal production in the province.

 

A small deposit of argentiferous zinc at Bien Venue in the Barberton greenstone belt could be amenable to exploitation on a scale similar to that of the Maranda zinc mine in the Murchison schist belt. In the past, very small operations were established on minor antimony, cobalt, copper, iron, manganese and tin occurrences in the province.

 

COAL

 

All or part of the Witbank, Highveld, Eastern Transvaal, South Rand and KaNgwane coalfields are included in Mpumalanga Province. A number of significant coal seams possessing diverse characteristics are present and have a variety of potential markets in the power generation, export, domestic, metallurgical, liquefaction and chemical sectors. This is the most important coal-producing area in South Africa and supports some 65 collieries working several seams in the Ecca coal measures. The Witbank coalfield contains a large and very important resource of high yield export quality steam coal, especially in the No. 4 seam.

 

In the adjacent Highveld coalfield the equivalent or No. 2 seam contains low-grade bituminous coal which is better suited to synfuel and power production. As a rule, close to the surface the coal seams are highly weathered to dross and are not amenable to coal recovery from small-scale surface pig-rooting. In some cases, accidents of topography may permit the recovery of limited quantities of coal from low-cost adit mining, but generally the scope for small-scale operations is restricted to the value that may be recovered from the hand sorting of waste tips at operating collieries.

 

About eight farms in the Ermelo district are underlain by substantial resources of peat, which could have potential value for the horticultural industry.

 

INDUSTRIAL MINERALS

 

The following industrial minerals are being, or, in recent years, have been produced from mining operations in Mpumalanga: andalusite, chrysotile asbestos, clay, kieselguhr, limestone, magnesite, talc, shale, silica, sand, stone aggregate, dimension stone and ornamental stone. Commercial and industrial demand for these commodities stems from a variety of applications in the following general categories: abrasives, ceramics, chemicals, construction, fertilizers, glass, insulation, paint paper, plastics, refractories and synthetic fibres. In the industrial minerals field, and in addition to the normal provision of sand and aggregate to the construction industry, the province is particularly known for the production of chrysotile asbestos, magnesite, verdite and the popular dimension stone known as black granite.

 

At the smallest scale of production there may always be scope for potential entrepreneurs in the industrial minerals field to form alliances with existing producers and to supply raw material from nearby small surface pitting operations, provided that the mineral rights can be accessed. By the sporadic nature of such potential operations, maintenance of safety standards and proper rehabilitation of the workings would be problematic.