Open Cast Coal Mine


The mining industry of Southern Africa is of global importance. About half of the world’s vanadium, platinum, and diamonds originate from the region, along with roughly 36% of gold and 20% of cobalt. - SADC

The mining industry of Southern Africa is of global importance. About half of the world’s vanadium, platinum, and diamonds originate from the region, along with roughly 36% of gold and 20% of cobalt.

Electrotron CC was established in 1993 and operates out of Middelburg South Africa. They design and manufacture conveyor, protection, safety, communication, instrumentation, and management systems. They have a vast array of clients, however, the bulk of their clientele is centered on the mining industry in Southern Africa.

The Issue:

One of Electrotron’s clients operates a large open cast coal mine. Within this mine there are 25 overland conveyors – some as long as six kilometers. There is a control room that monitors and controls all of these conveyors, however, they lacked the ability to report on maintenance carried out. There is an arrangement of maintenance that must be completed. All conveyors and protection systems must be tested, by law, monthly. On a single conveyor belt there is a trip switch on either side every hundred meters. In many cases there are in excess of one hundred safety devices that need to be checked to ensure proper functionality.

Initially the client wanted to incorporate the maintenance reporting within their existing automation systems. However, it became clear that the cost to do so made this option difficult to justify. To further complicate matters, there was a mixture of Wonderware and Androit systems that control the coal plant. Electrotron suggested a more cost effective solution with Infinite Automation Systems (IAS).

Control Operations Setup and Solution:

Every conveyor belt in the coal mine had its own control room, or MCC. In each of these MCC’s there is a large VSD and associated panels containing the control and network equipment. As you can image, the coal plant is spread over a large geographical area. All the MCC’s are interconnected via a single mode fiber. The Electrotron equipment panel, also housed in each MCC, has a small 32bit microcontroller with ModBus RTU. All of the Electrotron safety equipment for each conveyor belt connects to the micro controller over a two-wire bus. A Moxa MB3170 is used as a gateway to provide ModBus TCP. The IAS server is housed in the main control room at the coal plant one KM away.

Installation of Mango:

For this project Mango (IAS software) was installed on a Mini ITX board with an embedded Intel Celeron CPU. Eight gigabyte ram and a 128 gigabyte SSD was used. The OS was Ubuntu Linux 64bit with MySQL as the data backend. This allowed the footprint to be small with no screen required for the server. A large 50 inch screen with the NUC Intel box running Linux Kiosk mode was installed in the control room.

Technical Solution with Mango:

In Mango each conveyor ModBus TCP gateway was added as a ModBus IP data source. The polling was set at two seconds for each device. On each data source, six ModBus registers were added as data points to read key information from each microcontroller like: the status of the conveyor belt, which device was tripped, and was it a left or right trip? As some of the ModBus registers on the microcontroller was bit information, meta data points were created using JavaScript to provide statistical information like conveyor availability. Alarms within Mango were setup to alert by email whenever a data source exception was raised after a settimeout. Additionally, event detectors were created to set virtual data points to indicate communication failure on the DGlux HMI. All the created data points were setup in the point hierarchy to ensure a clear data structure within DGlux.

Advantages of Using Mango:

Using Mango allowed the control center to see every device that was being tested. In addition the client can create reports using the data within any chosen time frame. This helped the client to not only operate within the confines of the law, but also from a commercial perspective in that the maintenance supplier was monitored. Duncan Stead of Electrotron saw first hand that the implementation of Mango was simple and easy, especially given the timeframe and scope of the project. Hardware and software choices were easy to make because IAS is compatible with numerous platforms.