Introduction
Underground coal mining has advanced substantially in the past eight decades since the first continuous mining machines appeared. The advent of the digital age brought with it the ability to use software and remote radios to control machinery. This was a substantial step up from pulling levers on the machine. When I started at Joy Mining Machinery in 2005, longwall shearers were still being sold with monochrome screens and cartridges to hold software. These technologies were comfortably out of date relative to the latest advances back then but were accepted as the latest technology in industry for those machines. Users were more concerned with the mechanics of the machine and how it performed than the user interfaces. Many of the automation technologies installed were simply switched to manual mode as operators preferred to control the machinery manually. Shearers had two operators, conveyor chain tensioning was fixed frame, and some run of face roof support automation was happening from infra-red triggering (due to unreliable serial power line shearer comms) but often users would just press buttons or pull handles to operate the supports individually based on human judgement. Over time this changed as the push to remove people from the hazardous conditions on the face forced a reliance on automated sequences and remote operations. Mine managements worked with the OEMs to get their automation working and then decreed they shall not operate without it. Each success was hard fought, often with many setbacks, frustrations and heated meetings preceding it. The process was imperfect but in the end a successful implementation was a triumph for all concerned and became the new standard in industry. Show success at one site and everyone else would follow suit. Fast forward to now and longwalls are highly automated equipment with fewer operators required on the face, yet they still require substantial manual activity. Room and pillar operations have not had the focus and investment of longwalls in automation and are still very manually operated. As I learned more about the industry it became apparent the reasons why automation advances so slowly. Let's explore the key reasons.
Complexity of mining activities
Mining activities are exceptionally complex, burrowing through coal seams filled with hazards. Mining requires management of a multitude of natural factors (including gas and dust levels, subterranean water, strata pressures, and environmental impacts) and human related risks (such as explosion prevention, ventilation, machinery and environmental safety). Each of these complexities adds additional requirements for automated or manual monitoring and controls.
Often complexity is introduced as a result of the equipment being used in the mining process. For example, a longwall operates on the simple principle of cutting a coal block with a shearer, conveying the material out on a series of conveyors, and propping the strata with powered roof supports whilst the mining activity retreats. The strata then collapses behind in a controlled manner. The complex machines that do this have thousands of individual moving parts, most with no electronic condition monitoring. Breakages in many of these, e.g. shear pins, hydraulic hoses, dog bones, flight bars, chains, etc, could lead to catastrophic consequences for the mining operation so they are monitored by humans walking up and down the face, watching and listening for abnormal sights and sounds.
Underground Challenges
Once the mining activity begins the machinery must deal with the environmental conditions around it. Dust and water generated by the machinery operation becomes a health hazard and significant challenge for automation systems to deal with. They can obscure or distort sensor readings, destroy electronic components, and vary the performance of the equipment making repeatable process difficult. An example may be dust suppression sprays that make the ground soft enough for the equipment to sink. This impacts the positions of the machine and without a method of measuring these changes would affect the way the machine must operate in the future. The absence of natural light poses some difficulties for some technologies, although artificial lighting is now prevalent in mining operations. And critically the lack of direct line of site to satellites orbiting the planet means GPS navigation is impossible underground. This means many of the technologies used to position robotics and machinery on the surface with high degrees of accuracy cannot be used in underground mining.
Availability of technology
Whilst technology has advanced substantially in the past 50 years, its implementation in underground coal mining hasn't kept pace. Electronics are required to be explosion protected in an underground mine through a number of techniques noted within the IEC 60079 series of standards. Apart from some simple devices, off the shelf electronic technologies are not compliant or certified to these standards and cannot be used. Often the simplest way to install an off the shelf device in an underground mine is to include it within a flameproof (Ex.d) enclosure. However, this adds cost, size and maintenance requirements to the machine it is fitted and is not always practical, depending on what the technology is. For instance, adding a drone inside an enclosure clearly wouldn't work. Another complication is that certification requirements are different from state to state in Australia and country to country. You cannot take a MSHA approved device in the USA and just install it in an Australian mine. Nor can you take an IECEx approved device with a certificate generated in Europe and install it in Queensland. Whilst the technical design may comply in each location, it must be certified appropriately for each legislative region. This is a costly exercise. And devices that are made in the millions for general consumption are not going to be re-designed for a few coal mines around the globe. Thus many technologies are simply unavailable to be used in underground coal mines.
Availability of investment
In today's environmentally and politically sensitive landscape, investment for coal mining is getting harder to find. New mining approvals are rare and equipment supply from China has disrupted the OEM space globally. Opportunities to sell premium products at premium prices are few and investments to develop new technologies that will result in minimal, if any, additional sales of core product make no commercial sense. Most new developments typically occur as a result of equipment sales contracts that are usually watered down to reduce OEM delivery risk. This is not ideal as the pressures of delivering to a contract aren't compatible with R&D activities that require flexibility to follow where the water flows, technically, financially, and on a time basis.
What's more, the existing technology base is getting harder and more expensive to maintain. As the software has become more complex, OEMs are needing more resources to ensure the 'patchwork quilt' stays together. It used to be acceptable to write code on the fly underground as bugs were being found and fixed. Doing so now introduces the potential to break already working code for not just one mine but every mine globally using the same core software. Requests for new functionality are coming in at a rate that OEMs struggle to manage and the revenues just don't warrant additional headcount. This isn't Microsoft where the core products are software and millions of users are influencing the outcome; software often is seen as a freebie that comes with the machine and machine sales don't substantially fluctuate with new feature releases. Whilst mines may lose millions of dollars in lost productivity without new automation features, that motivation doesn't always flow onto the OEMs if they can't perceive a return on investment. A more collaborative approach is needed where risk and cost is shared.
Supportability
Once new automation features are implemented, they usually require substantial support to embed them and quickly deal with issues that may arise. Many new technologies fail, even if they are terrific products, simply because they aren't well supported. Many times I've seen products that are installed and commissioned,, only to be put in manual mode and forgotten a few weeks later. They may be buggy and not work, not have sufficient training behind them, or not be customised enough to suit the particular site. Once a feature or technology is turned off it can be extremely difficult to win over the workforce for another try. It's important to have an on-site presence, constant communication, and fast responses to issues. And with workforce transience these efforts might need to be sustained on a regular basis.
Workforce implementation
A rigorous change management process that addresses physical and cultural change and manages risk is critical for implementing any new technology. Any downtime in a mine costs them big money and safety must be priority number one. Many suppliers seem to do poorly at this as they understand their products well but not their target users. Implementing new technologies takes time and must be supplied with an 'off' switch until it is mature so the mine can carry on when unexpected issues arise.
Summary
Mining automation in underground coal has progressed and continues to progress slowly due to all the factors noted but some of these are able to be improved upon. Future machinery designs need to be more automation friendly. R&D needs to be focused on the right areas of need and with the proper business principles behind them. A collaborative and open approach that aligns both the end user and the supplier from a business perspective can drive innovation and investment. And putting the right support around new technology and implementing proper change management at site will help to ensure great products become industry standards of operation.
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