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Extra capacity to Richards Bay at lower cost

01 Apr 1997

INTRO: Spoornet's coal exports are set to grow - if costs are cut to beat competition. While extra substations are going in, the target of 65 million tonnes a year will mainly be achieved through more efficient operations

BYLINE: Philip van Heerden

Senior Manager (Planning)

Spoornet

BYLINE: Dave Budler

Senior Manager (Strategic Planning)

Excoal, Spoornet

SOUTH AFRICA'S premier coal export line serving the purpose built deep water port at Richards Bay was inaugurated on April 1 1976. At the time construction of the line was authorised in 1971, it formed part of a plan to ship 109 million tonnes of coal from the Witbank mines over a 12 year period.

Design capacity at opening was 21million tonnes a year. Diesel operation had been envisaged for the first few years, but electrification was brought forward as a result of the 1973 oil crisis and completed soon after the line opened. Over the intervening period, successive stages of upgrading have taken place to increase capacity, and 58·3 million tonnes was hauled in 1995. In 1996 the tonnage of coal moved fell slightly to 58·1million. The current target for 1997 is 62 million tonnes.

Heavy haul on narrow gauge

The Richards Bay line forms part of Spoornet's 1065mm gauge national network, but qualifies as a heavy haul line in its own right. It is the increased worldwide demand for steam coal that has driven up throughput, requiring continual increases in capacity.

The challenge facing Spoornet's planners is to anticipate how the demand for capacity is going to change in future, so that management can implement timely adjustments while taking into account the long life of capital assets.

In a highly competitive market for coal, high tonnages will only be sustained if transport costs are reduced, so any further increase in capacity has to minimise investment in new infrastructure and rolling stock. The answer lies in tightening up operations.

Richards Bay Coal Terminal (RBCT) is the company which owns and operates the coal terminal at the port; its shareholders are the coal mining groups. RBCT co-ordinates the tonnage exported through the terminal from the various mines in the group in accordance with the particular RBCT shareholder's entitlement.

The mines load the trains, generally by means of rapid loaders, although low volume mines use front-end loaders and similar equipment. RBCT is responsible for unloading the trains at the port using rotary dumpers, with the wagons still coupled.

The present understanding is that Spoornet should be capable of handling a maximum of 65million tonnes a year, but the actual annual capacity which RBCT requires is negotiated a year in advance. This arrangement, though necessary for practical reasons, causes some difficulties for both parties.

The RBCT shareholders need to conclude their contracts in advance and to anticipate market opportunities. Ideally, they want to ship coal to the port at short notice according to demand. On the other hand, Spoornet requires a regular flow of traffic for maximum utilisation of its capital-intensive assets. To acquire additional rolling stock or change the railway infrastructure requires long lead times.

RBCT shareholders suffer financially if they do not fulfil their contractual supply obligations, or lose opportunities because they cannot respond quickly to new market demands. Spoornet faces additional costs if it over-capitalises, and cannot generate adequate returns over the long investment life of its assets, typically 30 years.

Because of the long lead time to increase railway capacity (both in terms of infrastructure and rolling stock), Spoornet's planners must look beyond the current understanding with the mine owners, and need a long-term perspective. This means understanding the long-term world demand for coal, and its price; the extent of economically mineable South African reserves; and the role of rail transport in the supply chain.

Present capacity

The coal line runs from Blackhill (the furthest mine) to the coal terminal in Richards Bay, a distance of 580 km. The sections from Vryheid to Richards Bay (212 km) and Ermelo to Broodsnyersplaas (93 km) were newly constructed in 1971-76, with heavy upgrading to ease gradients and curvature between Ermelo and Vryheid.

Because there was already 3 kV DC electrification in the area, the Blackhill - Ermelo section is at this voltage. From Ermelo to Richards Bay 25 kV 50Hz AC is used. This was the first application of 25 kV AC electrification in South Africa, although the new Sishen to Saldahna Bay iron ore line was being electrified at 50 kV at about the same time.

Initially, coal was transported in wagons with a payload of 58 tonnes and an axleload of 20 tonnes. As the line was upgraded, wagons with an axleload of 26 tonnes and a payload of 84 tonnes were introduced to reduce unit costs.

Over the DC section between Blackhill and Ermelo, trains are run in lengths of 100 wagons, but over the AC section from Ermelo to Richards Bay they are combined into 200 wagon lengths.

Between Ermelo and Richards Bay, the minimum headway is 30min which equates to a theoretical maximum of 48 trains per day in each direction. Presently, some 11 to 12 loaded coal trains of 200 wagons are run daily, together with a further 12 trains of general traffic - half the theoretical maximum. Allowing for paths lost due to track maintenance, malfunctions and operating delays, sufficient reserve capacity remains to meet anticipated increases in coal export tonnage.

Between Blackhill and Ermelo a similar situation exists in that there is no immediate requirement for an increase in line capacity.

Extra power

Four new AC substations are being installed which will increase overhead line capacity on the Ermelo - Richards Bay section to about 72million tonnes a year during the course of 1997. The sites for the substations, with a combined rating of 80 MW, were selected after careful analysis in order to limit investment to essential requirements only.

Because of the large incremental increases which new substations provide, the target of 65million tonnes a year required in terms of Spoornet's obligation was unavoidably exceeded. Additional DC substations were installed on the Blackhill - Ermelo section during 1996, giving a capacity slightly in excess of 65million tonnes a year.

Locos and wagons

The locomotive fleet comprises AC units from Class 11E (3900 kW), Class 7E-1 (3000 kW) and Class 7E-3 (3000 kW). Class 10E-1 locos of 3090 kW are used on the DC section. The capacity of the combined fleet meets the 65million tonnes a year requirement.

CCL and CCR wagons are used for coal exports; CCR denotes a braking system upgrade. The earlier CCL-1 and CCL-3 types were designed for 20 tonne axleloads and are known collectively as 'smalls'; they are now used at mines with axleload limitations, and can be redeployed for domestic coal traffic as the Richards Bay fleet is augmented with newer rolling stock.

Later designs (CCL/CCR-5 to CCL/CCR-9) with an increased payload and a 26 tonne axleload are known collectively as 'jumbos'. New coal wagons are exclusively of this type to reduce unit transportation costs. The capacity of the current export fleet is 61 to 62million tonnes a year, which can accommodate peaks in the presently-agreed export tempo. Further capacity increases can be provided either by building more wagons, or decreasing the current average turnaround time of the fleet.

Predicting future capacity

Investments in railway infrastructure and rolling stock need to be governed by two primary considerations: