BATTERY POWER UNDERGROUND
John Chadwick looks at new battery powered trackless machines going into the production environment and trials of others
Cutting the cord
Battery Electric Vehicles( BEVs) are exciting the world at the moment and that includes those in the underground mining environment. They are also exciting the exploration sector as companies look to develop new lithium mining operations and those for other high-tech minerals required by EVs. And of course the copper market has benefitted greatly with sustained high prices over recent months.
Canadian mines and OEMs are at the forefront of much of the work in battery use underground. RDH Mining Equipment, as a pioneer in battery electric mining equipment technology, is now working with strategic partners in Latin America to assist mines there in transitioning to battery power. Having been in use underground since 2011, RDH’ s battery electric powertrain technology has been extensively tested in the field. As a company focused on innovation, RDH continues to expand its battery electric line and offers all of its available equipment models with a battery electric powertrain option. RDH claims to be“ the OEM that first successfully brought battery power to hard rock mining.”
In Chile, RDH has partnered with Royal America, an industry expert in industrial electric / battery solutions. After 30 years in operation, Royal America has become the largest supplier of electric machinery in Chile, and, says RDH, stands out for its quality service and experience.
Sierra Metals, committed to being a leading corporate citizen in Peru, has taken the first step in transitioning to battery equipment with an RDH battery powered LHD at its Yauricocha mine. As the first mining company in Latin America to make the transition to batterypowered mining equipment, Sierra Metals, with
a focus on continuous improvement, could not ignore the health, environmental, operational and cost benefits of battery technology over its diesel and electric cable counterparts. After looking at the various battery electric equipment options available on the market, Sierra Metals decided to partner with RDH. Many mines are hesitant to take the leap to battery electric equipment, but Sierra Metals, like many other operators, felt reassured knowing RDH has over seven years of underground experience with battery electric powertrain technology and has been in the underground mining equipment industry for over 30 years.
More truck experience
MacLean Engineering is another company that has done a lot of work on underground battery haulage and has now completed some 200 km of ramp run trials on its battery electric BT3 Boom Truck, the purpose of which was to address the question of range anxiety on high-tramming units in underground mines,“ one that we hear routinely from mining companies and engineering consulting firms around the globe. These ramp trials are allowing us to validate performance modelling assumptions with actual performance data from the real world and real conditions of an underground mine,” MacLean reports.
“ An EV material haulage unit like a boom truck needs to be able to carry as much as 16,000 kg of cargo up 15 % and higher grades across rough road beds, so the question of how long / how far it will last underground is always going to be one of the first asked by potential customers evaluating the total cost of ownership for EV fleets.
“ We’ ve learned two key things from our ramp run trials to date: 1) you need to engineer the
Pictured here working underground, the Muckmaster 3TEB, RDH’ s 1.15 m 3( 1.5 yd 3) capacity LHD, designed for narrow vein mining and ideal for operations trying to minimise ventilation costs. RDH now offers battery electric powertrains on its complete line of equipment
mining cycle, not just the battery cycle; and, 2) the user experience of battery electric vehicle technology remains as important as the technology itself – UX meets BEV.
“ Connecting the battery cycle with the mining cycle rests on planning for opportunity charging – taking advantage of the duty cycle flexibility that onboard charging provides to plug into the mine’ s existing electrical grid during loading or unloading or at lunch break.
“ With this type of planned, quick top-up( for example 20 minutes of recharging on every second run during the duty cycle), you can maintain enough state of charge to achieve continuous EV mobile fleet operation across a full shift.
“ The grade of the ramp, the weight of the load, and the condition of the roadbed all impact the opportunity charging requirements of a BEV material haulage duty cycle, but not to the extent that opportunity charging, well thought out, can’ t respond to. And in this case, range anxiety essentially disappears.”
The same issue of user experience holds true for harnessing the full potential of regenerative braking on battery electric underground mining vehicles.“ What we have learned from our trials is that the feel of brake holdback going downramp is new for operators, so the full potential of down-ramp re-generative braking, especially with a full load( up to 35 % of the up-ramp energy use restored), isn’ t always maximised.
18 International Mining | FEBRUARY 2018