White Paper Prepared by Titan ICT, April 2019  |  Download PDF Version

Wireless Data Communications: What Solution is Right for my Surface Mine Site? 

1. Introduction

Today’s modern mine increasingly relies on the use of technology to deliver the safety and productivity expected. The use cases span multiple aspects of operations from safety systems such as slope stability radar, to information systems like fleet management systems and IoT to remote operations and autonomous vehicles (haul and drill). Enabling all of these applications is the communications technology that underlies them and, in particular, mobile communications. 

By their very nature, the mining equipment that requires broadband communications is mostly mobile. Consequently, the obvious solution to providing access is wireless technology. The solutions can take a number of forms and the right one is heavily dependent on the requirements of the business and its specific use cases.  

In this paper, we explore the most prevalent solutions being deployed in the mining industry today.

2. LTE

Readers would be familiar with mobile telephone networks provided by telecommunications carriers. The very same technology is becoming ever more popular with surface miners as a solution to its broadband wireless requirements. LTE(4G) cellular networks can provide high bandwidth data and voice mobility services over lower frequency bands resulting in better coverage, less infrastructure and granular control of quality of service (QoS). Because an LTE network provides a high capacity, QoS enabled and highly available network, it opens up a suite of new capabilities and possibilities to cost effectively enable automation and remote operation technologies for surface mines.

Whilst the technology used to deliver enterprise LTE (eLTE) is the same as that used by mobile telephone carriers, the applications, requirements and design of the networks are vastly different. Generally, carrier mobile networks are ill-suited to provide the communications services required for surface mining use cases. This is due to carrier networks being designed for a high density of devices (mobile phones) per cell that, statistically, do not communicate very often and require most of their bandwidth in the downlink and much less in the uplink. Traffic is mostly internet browsing or similar and service interruptions are an annoyance with minor, if any, repercussions.

Mining use cases are the polar opposite; relatively low density of devices per cell, transmitting often and regularly, uplink traffic equal to or perhaps slightly exceeding downlink traffic and the impact of service interruptions resulting in operational shutdowns costing millions of dollars. 

Infrastructure-wise, eLTE networks consist of an “evolved packet core” (EPC), eNodeBs (macro and micro cells), user equipment (UE) and backhaul transmission (typically PtP/PtMP microwave or optic fibre). Macro cells often have transmit power of up to 60W per sector and are mounted on towers or semi-mobile skids. Micro cells are typically mounted on trailers to provide infill coverage. 

These are relatively easy to move to accommodate the changing mine topology or for special purpose short term applications. The LTE network can be used to provide its own backhaul however, usually, microwave radio or optic fibre is used in order to preserve the precious licensed spectrum for device access bandwidth.

Advantages of enterprise LTE:

  • Low latency to support critical system, voice, video and autonomy;
  • Licensed frequencies used (can use unlicensed bands – LTE-U), effectively eliminating the risk of network interference and intrusion;
  • Permitted to use much higher power transmitters free of the restrictions of the unlicensed bands resulting in better coverage and less mobile infrastructure (trailers);
  • Greater spectral efficiency resulting in higher data rates per MHz of RF bandwidth;
  • Designed for seamless mobility – little to no service interruption during hand off between cells;
  • High reliability and availability to support critical systems; and
  • The ability to converge voice and data communications while maintaining traffic separation, QoS and critical voice requirements (MCPTT).

eLTE is more complex to design and deploy compared to WiFi solutions. Additionally, individual hardware and software components are more expensive. Generally, this is offset by needing less equipment to achieve the required coverage and performance due to the higher power and greater spectral efficiency of the equipment.

An often overlooked facet of eLTE is the versatility of some of the antennae available. Remote electronic tilt control is available giving operators the ability to adjust coverage or power density on a per sector basis to meet changing or short-term coverage or bandwidth requirements. This is achieved by tilting antennae down to provide better coverage under the tower or up to extend coverage further away. 

3. Wi-Fi Mesh

A wireless mesh network (WMN) is technology based on the 802.11 family of standards. They are created through the interconnection of wireless access points (WAPs) installed in fixed locations or on mobile platforms (typically trailers). Each network user (AP) is also a provider, forwarding data to the next node. The networking infrastructure is decentralised and simplified because each node need only transmit as far as the next node.

To form a mesh, WAPs have the option of using one of their onboard radios (2.4GHz or 5GHz) to provide the connection to the mesh network and the other for access. Alternatively, a separate, dedicated P2P or P2MP microwave system can be employed to provide backhaul.

In the latter case, care should be taken when using unlicensed systems to ensure the backhaul and access networks don’t interfere with each other. This can usually be achieved with the use of well designed channel plans or directional antennae for backhaul systems.

Some of the benefits associated with a WiFi mesh network include:

  • Rapid, automatic formation of wireless networks;
  • Self-forming, self-healing and self-balancing; and
  • Lower infrastructure and operational costs per unit of equipment.

However, there can be drawbacks when using WiFi mesh including: 

  • Compared to LTE, WiFi mesh WAPs:
    • Provide smaller coverage area due to transmit power restrictions;
    • Require more equipment to achieve the equivalent coverage and bandwidth; and
    • Lack over the air QoS. 
  • The bandwidth to a WAP in the mesh is effectively halved with each hop from the root WAP;

  • Unlicensed frequencies mean susceptibility to interference;

  • Not designed for seamless mobility – handoff between WAPs can cause interruptions to service; and

  • No capacity for critical voice communications.

4. Proprietary Technologies

LTE and WiFi are standards-based wireless technologies that, in theory, allow a mixture of vendor equipment. There are also proprietary wireless technologies that may provide some advantages.

The use of MPLS technology and seamless mobility (with make before break handover) may deliver performance superior to WiFi without achieving the equivalent of LTE, but at a WiFi price point. 

Vendor lock-in is one of the disadvantages of this approach, however, some of the additional advantages may be:

  • Akin to WiFi mesh, there is no requirement for licenses;
  • A distributed control plane;
  • Higher spectral efficiency than WiFi due to proprietary media access control scheme or higher modulation schemes; and
  • Better use of MIMO to increase throughput.

5. Common Considerations

When contemplating a broadband wireless solution for surface mining, there are some common components between all the solutions.

Experience shows that at least 50% of project capital costs are associated with the balance of plant – independent power systems, trailers, towers, skids, huts, cabinets, IP network equipment etc. The quantities of plant are highly dependent on the network design which flows from the system requirements.

An example being the number of trailers required to provide the required bandwidth and coverage – typically (dependent on mine topology and terrain), LTE will require far fewer trailers than WiFi mesh for infill coverage. This aspect alone saves on balance of plant resulting in similar total cost. 

Operational considerations can also contribute to total cost of ownership. Less trailers in a network will require fewer equipment movements when blasting which can result in material cost savings – this is a benefit of LTE. However, WiFi equipment is usually more familiar to, and better understood by enterprise network engineers meaning less training than the specialised LTE equipment and architecture.

6. Conclusion

In summing up, surface miners have a range of technology solutions at their disposal for providing mobile broadband. These solutions are now mainstream having been deployed and tested in numerous use cases.

As with all engineering solutions, the design is highly dependent on the requirements flowing from the use cases and the budget of the organisation.

Time spent gathering and carefully considering requirements will increase the likelihood of the correct technical solution being chosen for the mine’s operations.

Whether that be a mixture of a stand-alone voice mobile radio system with WiFi or a converged LTE network supporting critical voice and data, the solution must cater for the operational needs of the organisation.

About Titan ICT

Titan ICT is an Australian-owned company specialising in strategic ICT advice, systems integration and technical support services to deliver high quality integrated technology and business solutions. With a proud record of delivery since 2003, we have a national footprint with offices located Perth, Brisbane, Melbourne and Sydney. From the outset the decision was made to focus purely on ICT disciplines providing trusted advice and engineered solutions that tackle technology transformation and maximise the potential of any

project, big or small. As a result, we are at the forefront of new technologies by constantly turning to innovation and ingenuity for the development of tailored, leading-edge solutions that support the operational and strategic objectives of the companies we work with. By working with us, you too can enjoy the success

that results from the bringing together of worldclass skills, best in breed products and practical know-how in planning, managing and delivering complex scopes of work.

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Disclaimer

The author only represents himself as competent professional in the planning, design and implementation of Telecommunications and Information Technology systems, networks and practice. Any statement provided which may be of a legal nature is only offered as an opinion based on the author’s understanding of the law and how it may apply. The author has made every effort to identify all relevant and available source data in the preparation of this document. All surveys, forecasts, projections and recommendations are made in good faith on the basis of information available at the time. The author, its agents, licensee and/or other representatives disclaims any liability for loss of damage caused by errors or omissions, whether such errors or omissions resulted from negligence, accident or other causes. Neither the author, its agents, licensee nor representatives will be liable for any loss or other consequences (whether or not due to the negligence of the author or their agents) arising out of the use of information in this report. No responsibility is taken for the accuracy of this information in relation to pricing or functionality of products and services described in this report. Readers should confirm with the appropriate service provider as to the validity of the information and any variations which may have taken place since publishing.