Underground » Communications
Some recommendations concerned with managing risks in the mine emergency response followed from an accident at an underground bord and pillar coal mine at Moura in 1994. For example, the emergency management team need to know where people are trapped in a mine. If the mine power system fails, the location monitoring system should remain active for a period and the system should be able to survive failures in districts. The Location And Monitoring for Personal Safety (LAMPS) system was conceived to address these requirements.
The first phase LAMPS project, ACARP C7037, developed and demonstrated novel location monitoring technology. This second phase project, ACARP C9016, is concerned with commercialising the location monitoring technology developed in ACARP C7037, for application within underground coal mines. The project involved collaborating with a commercial partner, developing a mine-ready system including intrinsically safe hardware, and providing mine demonstrations.
A request for expressions of interest was advertised in the national press, which culminated in the selection of MineCom Australia Pty Ltd (who supply mine communication and tagging systems) as the project commercial partner. Collaboration with MineCom guided the follow-on project developments.
The following subsystems have been developed:
- an intrinsically safe bi-directional (type I) tag that is powered by an external battery such as cap-lamp batteries;
- an intrinsically safe transmit-only (type II) tag that possesses an internal battery;
- a (type 0) reader for installation within a non-explosive risk zone (NERZ);
- an intrinsically safe (type I) reader for installation within an explosive risk zone (ERZ);
- a media converter for communications between readers and computers, and
- tracking software.
The readers have three pairs of optical fibre transmitters and receivers for interconnection with other readers or computers. The length of fibre optic cable between readers can be at least 4 km, which is consistent with the gate roads of longwall mines. Groups of interconnected readers can be supported by battery-backed uninterruptible power supplies, which provides some robustness to failures.
When tags are carried in vehicles, the tag detection rate decreases for increasing vehicle speeds and increasing numbers of tags. In the case of some above-ground trials, where there are no intervening obstructions between an overhead reader and a vehicle, it was observed that up to 20 tags can be reliably detected when the vehicle speed is not greater than 40 km/hr.
LAMPS appears to be the first location monitoring system in which both tags and readers have been certified to the current international IEC standards for use in hazardous regions within underground coal mines. Patenting action was carried out in Australia (Patent No. 753168 granted on 9 Apr. 1998) , the USA (Patent No. 6339709 granted on 15 Jan., 2002), Australia (Patent No. 753168 granted on 9 Apr. 1998) and Canada (Patent No. 2,289,752 granted on 3 Aug., 2004).
In 2004, the LAMPS type II tags are priced by MineCom at less than $100 each. Since the tags are predicted to last for over two years, the annual cost of increased personnel safety is less than $50 per person.
The primary application of LAMPS is to assist with personnel safety management. This information can be used to ensure that there is adequate provisioning of safety equipment underground. The system can provide last time and identified location of personnel.
Some mines have up to 30 km of underground roadways. Consequently, considerable time is often spent searching for underground equipment. Since the LAMPS type II tags are standalone, they can be attached to any assets that are mobile.