IM 2020 March 20 | Page 18

BATTERY AND ELECTRIC VEHICLES GHH’s new tethered battery-electric loader, the LF-19EB, is predominantly for soft-rock applications and specifically designed for loading into a feeder breaker benefit of zero emissions and can operate in sections with limited to no ventilation, but unfortunately there is a significant loss in productivity, having to tow the machine with diesel-driven tow trucks between production ends, or get a generator set up to be able to drive it to the other stope.” This effectively means that although the vehicle may have high availability and productivity while working, it suffers overall low utilisation. The new GHH machine is equipped with a battery for tramming up to 2.5 km (depending on the ground condition), without the use of any utilities such as generators, and with greater independency than traditional tethered electric loaders, the company said. “This effectively improves the utilisation of the vehicle per shift, therefore improving productivity considerably.” The machine comes with a 19 t payload capacity, a tractive effort force of 380 kN, an average of 250 kVA under permanent load and 315 kVA peak, and has a maximum cable length of 250 m. The loader can cope with the very high temperatures and undulating footwall conditions often found in underground soft-rock salt mines, according to GHH; it is able to operate at a maximum of 28% grade, 15% slope and at 52°C. On top of this, the rear of the machine is ergonomically designed with low and flat top covers to allow for maximum visibility for the operator as well as good manoeuvrability in tight spaces. The new battery-electric tethered loader comes with a significantly lower operating cost than both a diesel LHD and a traditional tethered electric LHD, GHH said. “Not only does the regenerative braking reduce both brake and tyre wear, thus reducing the predictive operating costs, but there is also no diesel engine, therefore no refuelling and a lot less maintenance due to having electrical components,” the company said. “The LF-19EB requires far less ventilation and also generates far less heat compared with a diesel LHD, resulting in a less negative impact on the operator.” Thanks to a direct driven gear box, axles and an 16 International Mining | MARCH 2020 intelligent motor management, the ride is extremely smooth, according to GHH, something that will be welcomed by any operator. “This loader is a perfect intermediate between tethered electric and a pure battery solution,” the company continued. “It is more flexible than a tethered loader and less risky than a pure battery loader, as long as the battery technology does not meet the requirements of an eight-hour shift. It is the perfect solution, especially for existing mines, when it comes to the power supply system because the battery is not only designed for moving the loader without cable, but also to buffer peaks in power consumption and recuperation.” Just as MacLean’s Marshall indicated, the need to charge battery-electric machines varies depending on the application. Companies such as Artisan are sticking to a battery change-out policy to improve the productivity of its battery-powered loaders and trucks – a solution set to become even more efficient with an automated change-out process in development – while others use either an on- board or off-board charging solution. Adria Power Systems, which has been building electrical infrastructure for mining for almost 25 years, specialises in the latter. Over this period, the Quebec-based company has built up a reputation for rugged and robust electrical chargers suited to underground mine conditions. IM caught up with Mathieu Bouffard, Adria CAN bus-type battery-electric machines working there. While Bouffard was not certain all BEV manufacturers would move to the CCS protocol that the likes of Epiroc and Normet are pushing for, he did say there were plenty of benefits to the design. “Working with the CCS, we have realised it is so well made – it’s so complicated that it cannot be hacked and there is a start-up routine that does all of the safety checks with the cables, so it is really robust and safe. There is no room for human mistakes within this.” In addition to working on a “bi-directional version” of this new charger – which could be available later this year – Adria’s Bouffard said the company was also developing a high-powered 4 MW charger for surface vehicles. This work is being conducted over a three-year period so may find its way into the development plans for the new crop of all-electric open-pit mines like Nouveau Monde Graphite’s Matawinie project, in Quebec. Judging by the data coming through from the Miller Relay electric utility vehicle, the unit has been working well at Young-Davidson. Paul Summers, Lead Developer, Electric Drive Systems, at Miller, said that, for utility and support applications at least, Miller is finding battery- powered electric vehicles are completely viable even in hard-rock mines with steep ramps (see graphs). Randy McCooeye, Safety and Risk Assessment Project Manager, to discuss the latest developments in the company’s offering. The company has recently been working with Miller Technology on a CCS charging protocol for Miller’s Relay electric utility vehicle at the Alamos Gold-owned Young-Davidson mine, in Ontario. The new generation charger from Adria allows for Level 3 DC fast charging via this protocol with type 2 plug as recommended by the GMG BEV guideline. Bouffard explained: “We’ve built another charging prototype before, but this is the first one with a CCS protocol. “We have just finished building the second one (CCS-type charger), which is going to be more powerful using two DC/AC outputs, which will be working in interleave mode. That upgrade is so we can filter and regulate the charge at any voltage/current with the same efficiency.” The company’s goal is to, within a month or so, swap the charger currently underground at Young- Davidson with this upgraded charger, then take the older charger to Kirkland Lake Gold’s Macassa gold mine, also in Ontario, to integrate into the During two days of utilisation from a beat mechanic (one of the higher daily mileage duty cycles for light vehicles) at Young-Davidson, Miller Technology’s Relay electric vehicle was able to complete work without opportunity charging and, at the end of the shift, there was still more than 30%charge remaining, Paul Summers says To charge, or change out?