Frequency link between two mine sites

Macarthur Coal wanted to install a new repeater, MV122 100 Mbps plus 4 x E1 licensed frequency link from Moorvale Mine site to Coppabella Mine, both open-cut workings.

Macarthur is one of Australia's major independent producers of coal for the production of steel. It is a key supplier of low-volatile PCI coal to the steel mills of Asia, Europe and Brazil and the process of expansion to service these markets has lead to the need to expand its communications services.

A new mine site, Moorvale, was established about 15 km south-west of the existing Coppabella Mine, about 140 km south-west of Mackay.

The company's plan was to expand the existing services at Coppabella to Moorvale that would enable all data and telephone calls to be routed through Coppabella and eliminate the need for a separate system at Moorvale.

Macarthur Coal had two options available to achieve its infrastructure goals. The first was to install a fibre-optic cable at a cost of about $350,000 and the second was to install a high-speed wireless system at considerably less cost.

However, the down side of the system is that it would require a clear line of sight between the two locations and this was not the case. So the mine called on Wave1 to provide technical advice, and its proposal to overcome this obstacle was for an intermediate site where a repeater that could 'see' both sites could be installed to provide the necessary clear line of sight between both mines.

This option meant that two back-to-back microwave radio systems were required which would double the supply, installation and licence fee costs but which would still be far cheaper than installing fibre-optic cable.

The wireless option has given Macarthur Coal greater flexibility, including the ability to relocate the system in years to come if requirements change and to expand the communications network for future projects in the area.

Wave1 installed large towers, which gave Macarthur Coal the option to add other systems as required.

In examining which was the best choice for its needs, Macarthur Coal considered the reliability of fibre-optic cable and had concerns including:

• Back-hoe attenuation. A fibre run in this location would cross a number of property boundaries and the potential for damage to the cable would be high.
• Obtaining the required approvals to dig and install a fibre-optic cable over this distance would be an issue and could potentially be a long, drawn-out process.

The system had to accommodate Macarthur Coal's voice and data services from Coppabella to Moorvale and had to support VoIP, E1 interfaces and fast ethernet.

The system also had to accommodate two separate subcontractors' needs with both voice and data links from Coppabella to Moorvale in the form of a separate 'on ramp 10 service' via its own E1 channel.

The Wave1 system gave Macarthur Coal 100 Mbps fast ethernet and 4 X E1 services. Separate data services were achieved using VLANs. Both the subcontractors installed their own PABX and could be billed individually by their carrier.