In 2003 Meridian installed a bin weight monitoring system at Mining Area C (MAC). The bin straddles the rail track and is used to load wagons. In 2010 some of the electronic hardware was upgraded to modernise the system. The original 2003 load cells on the columns have never been replaced and they continue to operate well today.
In early 2014 MAC approached Meridian for information on Meridian’s train weighbridges and Meridian’s train loading mass control system (TLMCS). MAC was seeking improved efficiency with wagon loading. The TLMCS can be retrofitted to existing bins and in this case the bin weighing system was included in the new works as one of the important components.
The basic concept of the Meridian TLMCS system is described as follows.
A train enters the loading facility crossing the Meridian tare weighbridge first. Here the train consist is automatically determined and an initial starting weight for each wagon recorded. A Radio Frequency Identification System (RFID) system is also used at the tare weighbridge to record the wagon identification number.
As each wagon approaches the loading chute, the Meridian speed and position system provides responsive real time updates of the wagon’s speed and position to the master controller. This information is used to determine an accurate opening position for the loading chute.
Once the loading chute is opened, real time data from the Meridian bin weight indication system and the conveyor feed weightometer allows the TLMCS system to calculate in real time the mass of material falling into the wagon.
The master controller is therefore able to issue a close-gate signal to target the required gross wagon load. The wagon then proceeds to be weighed by the outbound gross weighbridge where the system checks for target load and load eccentricity. Minor feedback can then be made by the system or the operator to improve loading performance.
Meridian recommended a ME-TrackWeigh 1D for the tare weighbridge and a ME-TrackWeigh 2D for the gross weighbridge. Both weighbridges have bolt-on load cells. The gross weighbridge has two weighing points and is more accurate than the tare for bogie and axle weighing applications. It also has a greater level of redundancy as it is able to revert back to a highly respectable. Trackweigh 1D system should an incident occur that results in damage to a weighbridge bay.
The system was completed in March 2015 with the assistance of Honeywell to modify the interface between Meridian and BHP systems. Wagons are now loaded under mass control at a significantly reduced variance around the target load. This has ultimately allowed the site to increase wagon loads since installation of the Meridian TLMCS.
The site has since been further upgraded to utilise Meridian’s new ME-Trackweigh-2DFR system which utilises 2 off ME-Trackweigh-2D systems providing an additional level of redundancy and accuracy.
