Gasguard consists of intrinsically safe real-time gas sensors, LED display and a programmable controller. The sensors are capable of continually monitoring toxic and flammable gases including carbon monoxide, hydrogen sulphide and oxygen, as well as methane.

The fixed installation sensors work as standard systems or in conjunction with Simtars Safegas monitoring systems for a wide array of applications, including monitoring gas on the longwall face, in development workings, and on mobile equipment such as continuous miners and bolting rigs. Using similar technology, Ampcontrol expects to release a diesel machine sensor by July to shut down vehicles in hazardous situations.

The IS Controller was designed to operate with a range of gas sensors supplied by Ampcontrol and other manufacturers, and allows information from the sensors to be fed onto any communication backbone. The sensors feature an LCD display, provide a 4/20mA signal and will operate from an IS Power Supply up to and including 16.3V.

The controller is supplied with four selectable 4/20mA input channels as well as three 4/20mA repeater outputs to operate remote displays or to allow monitoring by a PLC/SCADA system. This feature allows a single 4/20mA repeater output to be assigned to one or more channels to provide information of high and low gas readings. A modbus interface allows interfacing to data highways.

Customer configuration enables a mine to program the IS controller to site-specific parameters. Gas types can be set and setpoint levels adjusted.

In a complete mine-wide monitoring installation, the sensor data would be collected on Ampcontrol’s iMAC long distance signal line system. An integral component of the Gasguard system (though not requisite), it provides unprecedented supervisory control and is used in several other applications, such as Ampcontrol’s VoiceCom system on longwall face communications and conveyor signal line systems.

These technologies make it possible to monitor the underground atmosphere in real-time from the surface, using intrinsically safe communication systems.

One iMAC controller can address up to 85 Analogue Input Modules (AIM) providing advantages including a reduction in cables (as iMAC uses only two wires for a data network of up to 10km); reduced installation cost; and better preventative maintenance.

Ampcontrol Electronics operations manager Rod Henderson believes industry uptake of Gasguard has been high due to the equipment demonstrating long-term reliability in the field.

“In our design approach we looked at what was out there, we listened to the industry and took on board what they wanted,” he said.

As an example, Gasguard sensors are housed in a cast stainless steel enclosure that has been shown to be exceptionally robust. The design protects the sensor head from moisture, meaning it can be hosed down and continue to operate, unlike some other products.

Henderson said Gasguard was rapidly earning a reputation and becoming synonymous with gas monitoring in underground coal mining.