new dual-energy transmission (Duet) system for direct through-belt ash-in-coal determinations has been installed by AngloCoal at its New Vaal colliery.
The low-cost, low-maintenance system was installed within days of its release at a recent Southern African trade showgold mine investment project in zimbabwe
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Manufactured by Scantech in Australia, it is being marketed regionally by Chromatech Instruments in Johannesburg.
The distinctive C-framed through-belt analyser is being used to continuously monitor final product, being conveyed to the stockyard feeding to Eskom’s Lethabo power station.
The Scantech Coalscan 2100 has been installed at New Vaal for trials.
Acceptance depends on the analyser demonstrating that it offers economic benefit.
The system measures the percentage of ash in coal using dual-energy gamma-ray transmission.
By making many measurements a second, it integrates the data acquired into a user-configurable system output used for real-time quality-control.
The system caters for plant inputs and outputs.
There are four plant inputs for connection to a belt-weigher and other plant signals, and two analogue outputs from the Coalscan for instantaneous ash tonnage weighted average ash.
The system is equipped with a serial interface for data output in Modbus protocol for connection to a laptop computer or a plant control system.
It is suitable for high-speed applications, including sorting, run-of-mine monitoring, product monitoring and stockpile building.
Static calibration of the analyser takes place off-belt without conveyor operations being disrupted.
Users can easily and safely fine-tune the system off-line via a swing-off C-frame.
Safety and user-friendly features include a fireproof drop-tested lock-off protective shutter for the unit’s source.
Designed to meet international regulations, these features ensure that the source is secure for service work.
Speaking after the release of the 2100 at a recent industry process equipment expo in Gauteng, Scantech senior physicist Ken Smith and Chromatech product manager Bryan Buttemer explained that the variation in the mineralogy of the New Vaal colliery coal presented a challenge for Duet analyser technology.
The challenge comes from the variation of iron and calcium in the coal.
The coal is blended before the feed reaches the Coalscan 2100.
The conveyor running through the analyser delivers 2 300t/h – 4 000t/h at its peak.
By measuring the ash on-line, the colliery is able to deliver a more consistent product because the analysis permits New Vaal to make on-line changes in the washing process.
Developed to help the user achieve the optimum, the unit allows for a deeper bed depth to be tackled than previously possible.