Mining Case Studies

An order for a Spillminator with Vesconite bushings at the pivot points was dispatched by Lani Service Centre to a South African gold-mining company in September 2017.

A Spillminator is a piece of equipment that lies within a standard bulkhead installation and attaches to the hanging wall overpass chute opening to control the flow of ore onto hoppers or conveyors in underground mines.

It comprises two doors, including primary and a secondary back-up door, which are pneumatically driven and manually operated.

The primary door allows the required ore to pass through the chute, while the secondary door ensures that the chute remains closed in the case of a mud rush. In the case of a door jam, the secondary door serves as a backup to avoid any ore or mud passing through and compromising worker safety.

Lani Service Centre workshop manager Jonathan van Biljon informs that Vesconite bushings are installed at the pivot points around which the two doors, which lie at either side of the chute, rotate.

The bushings are desired because they are self lubricating, can withstand the high pressures involved in the application, and are able to cope with a dirty wet mining environment, he says.

Van Biljon informs that the company, which repairs and manufactures many engineered products out of steel, produced eight doors (or four set ups) last year and has produced two doors (or one set up) this year, following a successful tender.

He notes that many mines use Spillminators of different sizes.

This specialised application is being introduced widely since it ensures the efficient flow of ore, without spillage. It also ensures that staff and machinery are protected from mud rushes that have historically claimed lives as well as resulted in equipment damage in South Africa’s mining sector.

A South Africa mining company using peripheral grinders to sharpen steel bits on rock drills contacted us for a replacement solution to high-wear bronze bushings on its grinding machines. This application receives no lubrication and operates under a great deal of dirt and grit, which accelerated wear rates on the bronze bushings. Vesconite bushing were machined and fitted to this application, and have performed superbly for the past two years.

A earth-boring company was looking for a durable material to create stabilisers for its borer machines. The machine bores between levels in mines and is capable of boring chutes up to 120m. The drill steel is subject to high levels of grit and rock. The Vesconite stabilisers help align the drill steel, thereby avoiding whip in the drill. Despite the dirty conditions, the new stabilisers required no lubrication between recommended overhaul schedules, and general maintenance and downtime were substantially reduced.

Flask doors are opening mechanisms allowing ore to pass through and into a skip situated below. Knuckle pin bushes, used on the door’s opening mechanism, are traditionally made from bronze. In this particular instance, the original bushes were subject to heavy wear and eventual seizure due to dirt and lack of lubrication – accessing these bushes is difficult. Vesconite bushes were retrofitted to the mechanism. External lubrication was no longer required and Vesconite’s remarkable ability to function well in dirt and grit meant that maintenance and replacement schedules were greatly reduced.

South Africa – A mining company sought a harder-wearing alternative to white metal liners on filter rakearms. These rakearms are used to stir the gold bearing solution at the bottom of the filter and as such are subjected to harsh and dirty conditions. The Vesconite bushings were machined and fitted, with excellent results. Unlike the original white metal bushings, the Vesconite replacements are easy to remove and refit, and offer both far longer life and considerable cost savings.