Advanced Gas And Methane Drainage   Monitoring Systems For Uk Coal

Thoresby Colliery has been equipped with the latest Trolex Sentro 8 gas and environmental monitoring system and also a Trolex Sentrum methane drainage monitoring system.

An intensive two-year development programme by Trolex (UK) on Sentro 8 resulted in a new concept in environmental and gas detection. An integrated multi-purpose sensing station ready to be configured to meet gas detection and condition monitoring requirements without the need for complex investment in system design or the need for specialist back-up. The system features intelligent inter-changeable sensing modules served by universal data communications architecture, making it straight forward to network sensor stations to a master computer and expand the system if required at a later date.

Sentro 8 is so named as it can accommodate up to 8 pre-calibrated sensing modules. These sensing modules are literally intelligent ‘plug-and-play’ elements, each with its own processor for intelligent data storage and signal conditioning circuits. Indeed, they have a massive capacity to store up to 4,000 points of data. They are designed to continuously display the data they retrieve, store the full service history such as data logging, calibration, failure modes and alarm settings, and they run self-diagnostic checks. They are also designed to be simply replaced with pre-calibrated modules whenever required, making maintenance, service and calibration straight forward.

At the Thoresby Colliery, the environmental or eModules used are for detecting CH4, O2 and CO in two ranges from 0 - 50ppm and 0 – 500ppm. The colliery is also using remote or rModules with an output of 0.4 to 2V for remote sensors.

Also installed at Thoresby Colliery is the Trolex Sentrum system, another product which was in development for two years before being launched last year. Unlike other systems before it, the Trolex Sentrum system keeps continuous high accuracy monitoring of methane. It uses complex algorithms to correct the effects of non-methane hydrocarbons cross-sensitivity, together with mass flow calculations. It uses infra-red detection coupled with a unique method to measure the methane content from the sample on a continuous basis. The way this works is that an initial gas analysis is used to ‘train’ the system and subsequent analysis can be used to fine-tune the system. Contributions to the overall signal from the detector caused by methane and other hydrocarbon gases are evaluated and the methane content is derived from the overall signal and the individual contributions from the different gases.