Underground rail networks used to transport mined materials may be poised for future growth, owing to the high cost of trackless machinery and other alternative transport methods.

Railway and civil engineering contractor Loning Hill Properties contract manager Attie Claassen tells Mining Weekly that efforts were made in the past to establish trackless mining in many mines across South Africa. However, the expense of trackless machinery has proven to be a significant problem, especially when taking into account “a proven railbound network”.

Claassen believes that an increasing number of mines will revert to quality installed railway lines in the next few years. He explains that the biggest problem with older generation underground railbound lines is that experts were not consulted in the installation of these railbound lines, which reduced the life span of the rail system considerably.

Claassen adds that a correctly installed rail system has been proven to far outweigh its initial capital investment, and is, therefore, “the way to go”.

Projects in Progress

Loning Hill Properties has several projects under way to upgrade, monitor, refurbish or replace rail lines at various mines across South Africa.

The company started upgrading a five-kilometre stretch of rail line in September last year at gold mining major Gold Fields’ Beatrix North shaft, in the Free State. The project involves upgrading tracks from levels 22 to 26 in the mine, which includes excavating and replacing all perway material and installing a dedicated drainage system, complete with a precast concrete kerbstone and retaining wall that is pinned into the footwall with a Y16 ripple bar.

The rail sleepers are 10 t concrete Mineclip sleepers, manufactured by multidisciplinary construction and engineering group Aveng Grinaker-LTA.

The kerbstones are manufactured at a surface plant at the Beatrix shaft, with rail upgrading being done in accordance with SANS 10339 class A specifications, says Claassen.

A project is under way at the Beatrix South shaft for the full upgrade of rail lines on levels 22 and 23 of the mine, which spans 1.8 km.

The project is similar to the Beatrix North Shaft project, but with a few key differences, such as the replacement of all the existing 30 kg/m rails. Further, no precast kerbstone can be used, owing to space restrictions, necessitating the on-site manufacture of a slimmer wooden retaining wall and installing it in a thick bed of concrete.

Loning Hill Properties was awarded a three-year contract in September last year for the continuous maintenance of rail networks in diversified mining major Anglo American’s New Denmark colliery, in Mpumalanga.

This project will focus on the rail networks from the colliery’s Okhozini shaft to the Central shaft. These lines carry heavy equipment for use in the longwall mining of the coal seam. “The importance of maintaining a good running top is paramount, as derailments of such massive equipment is costly, but preventable,” states Claassen.

He adds that Loning Hill Properties will use a programme to continuously assess and rectify any identified defects to keep the whole system operational.

Frequent Monitoring

Claassen tells Mining Weekly that, according to best practice, it is preferable to check the condition of a railway network on a monthly basis, at least.

“Based on the results of these assessments, appropriate planning can be done for planned maintenance, where needed,” he explains, adding that if regular maintenance procedures are performed on a working rail network, the life span of that network will be increased considerably.

“This is the Achilles heel of most underground railway systems, as the maintenance of the system is normally abandoned up to a point and only the proverbial hot spots are rehabilitated,” says Claassen.

Moreover, he states that wear-and-tear on well-maintained railway networks will be minimal, owing to the smooth and proper workings of such a rail system.

“A quality installation might easily last from 10 to 15 years, whereas an incorrectly installed network can deteriorate within three to five years,” he adds.

Proper Drainage

Underground railways are not much different from surface railways, says Claassen, adding, however, that the scale of all materials used is larger with surface lines to accommodate bigger loads.

He explains that the main difference between underground and surface railways is the environment – surface rails are naturally well drained and mostly bone dry from exposure to the sun, compared with underground rails that are often installed in a moist or wet environment, with water drainage being the biggest obstacle to the underground network.

“Excessive ingress of water into a railbound haulage wreaks havoc and ultimately destroys the whole system,” says Claassen.

Operations

Loning Hill Properties employs a trained labour force to conduct quarterly or yearly railway asset reports using an electronic laser-enabled track-measuring device, which is able to measure and plot four of the key measurable parameters of a quality rail system.

“This information is collated and compiled in a comprehensive report, which serves as a great management tool that gives mining companies a snapshot of their whole railway infrastructure,” says Claassen.

“Our advantage against our competitors is our proven record, expertise and personal hands-on approach to any challenges that may arise. We are regarded as contractors that create minimal interference with daily tramming activities at a mine, and this makes us a preferred contractor, as the client has limited downtime in their tramming cycle.”

Loning Hill Properties aims to further expand into Africa and aggressively market the company to African clients as a preferred railway contractor.

“We have had a lot of enquiries from outside South Africa’s borders and we feel this is an area where we can expand significantly,” says Claassen, adding that he would like to see more growth of underground railways in the platinum sector.

“We are working towards numerous projects to realise this vision,” he concludes.