Zinkgruvan Mining AB is an underground mine in south-central Sweden owned and operated by the Lundin Mining Corporation, a Canadian base metals mining company. It comprises of an underground mine, a processing plant and associated infrastructure. The mine produces zinc, lead and copper concentrates.

The mine is accessed principally via three shafts. The primary P2 shaft provides hoisting and man access to the 800m and 850m levels with the shaft bottom at 900m. A ramp system is used to access mine levels below the shaft with the deepest level now approximately 1,400m below the surface. A ramp connecting the underground workings with the surface provides direct vehicle access to the mine.

The main impetus behind the installation of a private LTE system is to create a platform for further digitalization, support autonomous vehicles and enhance automatization - all key drivers to make the mine more efficient, safer and less costly to operate.

LTE will provide the platform for improved tagging and a new means of voice communication. The existing DMR radio system covers all areas of the mine, while the LTE system only provides coverage in one third of the underground tunnels, typically those areas with active production.

The majority of the mine staff work in areas with LTE coverage, and were not keen on carrying two communications devices. The major requirement, therefore, was to integrate the existing DMR Tier 3 trunked radio system with an LTE-based PoC (Push-to-Talk over Cellular) system. This ensures all staff can communicate with each other at all times across the entire underground mine and surface areas.

Another key requirement was that all users have access to the same functions and features whether using a DMR radio or an LTE-based device.

For easy operation, LTE users were included in the radio’s address book and the radio numbers were included in the dial list in the LTE device.

There are no noticeable delays in communications between radios and LTE devices even though the PTToX installation is located “off-site”. A slight difference in voice characteristics was all that the users mentioned.

The call diversion feature is proving very handy, as calls to a radio user are forwarded to the LTE device when the radio is turned off. Calls to the LTE device are forwarded to the radio when the LTE-device is out of cellular coverage range.

The Tait EnableFleet application makes configuration changes and firmware upgrades as easy to carry out for PTToX as for DMR radios. Changes are transferred instantly via over-the-air programming from a remote centralised location.

The Tait PTToX solution enables Zinkgruvan Mining to continue to reap the benefits of its existing DMR Tier 3 system, while enabling DMR and LTE devices to intercommunicate with each other. This will enhance operational efficiency and safety, while providing a strong platform to support the introduction of further broadband-based applications such as increased automation, autonomous vehicles, sensor-based safety alerts and the like.