Why GMSG and CMIC’s latest guideline is a key tool for the resources industry
As mine operators are forced to move deeper underground to collect precious ores and minerals, and regulations around diesel particulates and carbon monoxide emissions tighten, the operating costs on properly cooling and ventilating mines safely for personnel will only increase. Innovation in batteries and battery electric vehicles (BEVs) have advanced to the point where commercial trucks, cars, trains and buses are more efficient than the internal combustion engines used in diesel-based vehicles. BEVs present a unique opportunity for mining companies to move away from the traditional diesel-based equipment that create the need for extensive ventilation and cooling infrastructure, but only if the cost of implementation does not exceed that of standard operations.
GMSG Recommended Practices for Battery Electric Vehicles in an Underground Environment was developed by Global Mining Standards and Guidelines Group (GMSG) and the Canada Mining Innovation Council (CMIC) as a result of direct stakeholder requests. When mining companies sought to make the transition from diesel to electric, it was quickly discovered that the industry was lacking the tools to properly implement BEVs in an efficient and cost-effective way. David Sanguinetti, President of Sanguinetti Engineering, and guideline project manager, has said that the guideline is a great example of innovation through collaboration.
The guideline has a number of functions: it leverages existing standards and research on BEVs from within the mining industry as well as outside industries, including automotive, electrical and automation. Since it is structured as a specification, it can be used by mining companies in tender documents to original equipment manufacturers (OEMs), and, in turn, can be used as a blueprint for OEMs in their research and development. While these existing standards are presented through the lens of recommended practices for underground mining environments, the intent is not to impede innovation but to give an overview of the options currently available. In this way, the guideline also serves as a discussion document on the unique challenges that BEVs present for the mining industry.
Explaining the value
While innovation around BEVs continues to develop, no documentation on how to effectively implement their introduction into a mine setting existed before this guideline was published. The guideline offers a comprehensive overview of the advantages and disadvantages of BEVs, with a scope that provides guidance for mining companies seeking the specifications for purchasing equipment, and OEMs with the information to begin standardising BEV equipment for interoperability.
There are several advantages for mining companies to use BEVs over traditional diesel-based equipment. The World Health Organization has classified diesel emissions, such as carbon monoxide and dioxide, nitrogen and sulfur oxides, hydrocarbons, and particulates, as a ‘Group 1: carcinogenic to humans’. As a result, there is a steep operating cost to protect workers from potentially harmful emissions, including ventilation and cooling infrastructure. Those costs are reduced with the use of BEVs.
However, BEVs present a new set of challenges, with a more complex charging system and new safety concerns, as opposed to the simple refueling process with diesel-based equipment. The intent of this guideline is to help mining companies and OEMs to avoid potential added costs by providing guidance on considerations for charging philosophies, mine design and BEV design.
The guideline was launched in June 2016, with several workshops held in Canada, the US, Australia and South Africa. While a guideline of this magnitude would generally take more than a year to develop, the level of support from stakeholders to get a guideline out quickly led to a large amount of resources being pooled in a short amount of time. More than 100 technical experts from mining companies, OEMs, original technology manufacturers (OTMs), research organisations, government organisations and consultants volunteered to write or review various sections of the guideline. As a result, the guideline was published in April 2017, just ten months after the project was launched.
The recommended BEV practices are described in the context of six core topics: Charging Philosophy, Mine Design, BEV Design, Energy Storage Systems, Charging Systems and Performance Standards. The guideline gives explicit details on the safety values and procedures for each, making safety one of the most crucial considerations for users of the guideline, including mine operators, OEMs, or any other industry stakeholders.
The charging philosophy is considered the ‘foundation of electric mine design.’ It is the very first key consideration the guideline offers, and is described as the charging system that an electric-based mine is designed around. To begin, the guideline presents the four existing approaches to BEV charging: on-board charging from alternating current (AC) supply, off-board charging of on-board batteries (transformers and rectification equipment located in a fixed enclosure removed from the BEV), off-board charging of off-board batteries (swapping) and a hybrid charging method (a combination of off-board and on-board charging methods). From there, the guideline outlines the key advantages and disadvantages for each of these approaches, depending on the requirements of a given mine. Specific recommendations include consideration for standardising the type of charger used and designated parking arrangements for charging stations.
This leads into the next crucial factor—the mine design. It is in this section that the guideline outlines some of the unique challenges in implementing BEVs in underground mines, such as the length of time a battery can hold a charge during a shift, and the more complex requirements of recharging a BEV in comparison to the simple act of refueling.
An example of a key consideration for mine design is the haul route. Smart mine design would account for the BEV range of movement and ability to hold a charge. For example, regenerative braking is an effective method of allowing more energy to be stored, allowing vehicles to run longer. If a truck is primarily hauling material downhill, rather than uphill, it consumes far less energy and will have the capability to run for several shifts.
While the former sections are primarily geared toward mine owners and operators, the latter sections on BEV design and energy storing systems offer OEMs the most benefit. Recommended practices for BEV design are provided for the following considerations: Operator Interface, Braking System, Electrical Systems, Shock and Vibration, Fire Suppression, Accessibility and Service, Emergency Stop, Master Disconnect, and Insulation/Ground Fault Monitoring. Each subsection provides detailed information on the standards currently available for each design component, with a concluding overview of safety recommendations. Similarly, the section on charger design outlines the safety recommendations of developing a charger, with consideration of the charger output cable, operation and controls, and communication and monitoring.
The Energy Storage Systems section outlines the safe use and storage of batteries. Lithium-ion batteries (LIB) are currently the most commonly used for BEVs, due to their high energy density in comparison to other types, such as lead-acid batteries. Hazards such as overheating or overcharging can pose a serious risk to operators and technicians, so this section covers the functional and safety requirements of batteries, including thermal management and testing, cycle performance, fire suppression, end-of-life procedures and hazard identification and effects.
The guideline concludes with an overview of performance standards, describing the type of data and information required to assess the capabilities of battery-powered equipment for underground mines.
The guideline has already been met with resoundingly positive feedback from the industry. It debuted in Montreal, Canada at the 2017 CIM Convention to a sold-out workshop, with a wide cross-section of the industry in attendance.
One key message was from the OEMs in attendance, who expressed the value of the guideline, despite the extra work it will create. Sanguinetti noted that now OEMs have something they can work with, with mining companies, to say, ‘here is the information we need to properly specify a battery electric vehicle for you, for us to supply what you want.’ He said that the best feedback he received was when an engineer at Atlas Copco, who is responsible for electric vehicles, said that the guideline is now required reading for all Atlas Copco engineers.
Thanks to the rapid and constantly evolving nature of technological innovation in the mining and automobile industry, standards around BEVs are in a constant state of flux, with the possibility of new ones already being developed since the guideline’s publication. The project group is actively accepting new recommendations, edits and suggestions from guideline readers for a second edition of the guideline, which is expected to be published in 2018.
Alain Richard, electrical engineer at Bestech and guideline author, has said that once the guideline is implemented in operations, it will be interesting to see if what the guideline authors imagined is true and include those outcomes in subsequent revisions, to assist the industry in making the shift as a whole.
It is only through a continued collaboration that the guideline will be able to evolve and successfully meet the needs of the mining industry. Any industry members interested in the project are invited to contact the project leaders to learn how they can contribute. Contact GMSG’s Working Group Coordinator, Jennifer Curran, at jcurran@ globalminingstandards.org.
The full guideline is available to read on the GMSG website in its online library at www.globalminingstandards.org.
Image copyright Atlas Copco.