Guidelines for Battery Electric Vehicles in the Underground - Mine Design April 30 th, 2017 Presented By: Alain Richard Cheryl Allen Electrical Engineer Principal Engineer Ventilation BESTECH Vale Ontario Operations
Introduction Alain Richard 6 years with BESTECH Power System Studies Feasibility Study Ventilation Control System Studies Electrical Design on the Onaping Depth project Cheryl Allen 30+ years in mining 16 years with Vale Mining Engineer Ventilation Design Research Studies BEV for Sudbury mine projects
Agenda Introduction and Intent Mine Layout and Infrastructure Personnel Movement Other Electric Equipment Charging Infrastructure Ventilation and Cooling
Introduction and Intent First assumption: BEV mines will be different than diesel mines Second assumption: Greenfield and brownfield mines have different opportunities to incorporate BEVs Intent: This is not a mine design 101 but rather points to ponder when designing a BEV mine
Mine Layout and Infrastructure Anticipated challenges to address: Range limitation on a single charge Emerging technology (depending on the vehicle size) Different design questions/requirements Changing perspective of mine owners, operators and designers Shift in maintenance resources
Ore/Waste Handing System (OWHS) OWHS large energy consumer Multiple design trade-offs required Need to ensure BEVs do not have a negative impact on the OWHS Impact of downhill haulage Impact of uphill haulage
Regenerative Braking the good Diesel vehicles convert all kinetic energy into heat With BEV it is possible to convert some of the kinetic energy back into electric energy while generating some heat Potential advantage: Longer BEV range Smaller Batteries Higher efficiency Reduced heat production
Regenerative Braking the bad Dis-advantage: Need proper planning and/or vehicle design to prevent overcharging Might need braking resistor and/or regular brake system Mine design may reduce full potential from regenerative braking Ex. Brownfield mine Experience is required to fully understand the potential
Vehicle Parking Typically not a constraint in the design for a diesel fleet With BEV, parking will be based on the charging strategy and needs to be carefully laid out Change in workforce culture
Vehicle Parking A mine monitoring system would ideally track the location and status of every BEV throughout the day Need to remove the chance of a worker starting a shift with a discharged battery
Personnel Movement Whether the mine is shaft access or portal access, changing to BEV needs to consider not just the movement of ore/waste, but also of people.
Shaft Access Near shaft parking Access vehicles via walking Requires sufficient parking locations and chargers near shaft Mining level parking Such as Jumbo, Bolter Need to transport workers to vehicles
Shaft Access Personnel carriers Access personnel carriers via walking Transport workers to the mining levels or distributed parking locations Combination Find the best balance for the application
Ramp Access Group travelling is strongly encouraged Increase efficiency of travel Long uphill travels -> very demanding on batteries Long downhill travels -> could be problematic with regenerative braking
Personnel Movement Summary
Equipment Groups Charge-while operating equipment group (Tethered) Load Haul Dump (LHD) Machines Alternate haulage methods Auxiliary Vehicles
Tethered Equipment Vehicles that are typically plugged into AC power while performing work Bolters Scalers Jumbos Move with diesel or battery power Charging via AC cables Similar to some residential BEVs Smaller battery
Tethered Equipment Without an on-board charger Ensure charger access Potentially more chargers required Larger battery Key to review the duty cycle of the battery
Other Electric Equipment Load Haul Dump (LHD) Machines Mine-level grades, charging philosophy, fully tethered, hybrid-powered, inductive charging, trolley-assist charging Alternate haulage methods Conveyors, electric-powered trains, trolleys, monorails, RailVeyor TM and continuous haulage systems
Charging Infrastructure Production is dependent on capacity to have fully charged batteries Dependable charging infrastructure that fit for purpose
Design Prerequisites Questions to ponder: Shifts per day? Duration per shift? Equipment expectation? Equipment capacity? Number of chargers? Types of chargers? Opportunity charging? Charging philosophy Special needs? Ex. grader
Design Prerequisites
Charging Methods Simplified view of charging methods: If battery running time > shift length -> shift-change charging If battery running time ~ shift length -> shift-change charging + opportunity charging If battery running time < shift length -> battery swapping or in-shift charging In reality, other factors will come into play and affect the charging method
Charger Diversity Spectrum of possible scenarios Dedicated charger per equipment Limited to a few types of chargers One size fits all To balance a successful implementation and prevent limiting innovation, a few types of chargers will likely be required for each mine
Opportunity Charging Scenario 1: Opportunity: 2 30 min. lunch break + 6 10 min. bio break = 2 h/day Typical shift-change: 2 2h = 4 h/day Conclusion: A dedicated opportunity charger would have half the utilization than a shift-change charger
Opportunity Charging Scenario 2, staggered lunch breaks, dual purpose chargers Opportunity: 4 30 min. lunch break + 6 10 min. bio break + 4h = 7 h/day Typical shift-change: 2 2h = 4 h/day Conclusion: A shared charger could have nearly double the utilization than strictly a shift-change charger
Opportunity Charging Scenario 1, 50kW charger & 100kW battery 30 min. lunch = 25kW or 25% of charge Shift-change: 2h = 100kW or 100% of charge Conclusion: Interesting option to top-up the battery
Opportunity Charging Scenario 2, 100kW charger & 100kW battery 30 min. lunch = 50kW or 50% of charge Shift-change: 2h = 100kW or 100% of charge Conclusion: Interesting option to reduce battery size Can reduce range anxiety
Charging Stations Located near equipment; as recommended by the OEMs For Mine Engineers, chargers can be viewed as variable frequency drives Need to control: Dust Humidity Heat Vibration Percussion blast Water
Swap-out Stations Goal of a swap-out station is to provide a full charge in a short amount of time -> similar to diesel re-fueling Proper planning of vehicle traffic is key to prevent congestion
Swap-out Station Design Size of facility Crane system to remove and install batteries Must be compatible with all BEV types that use the system Sufficient chargers in proximity Sufficient spare batteries Potential rockmass quality issues due to size of excavation
Power Distribution Considerations Incoming voltage is typically 480-1,000V, 3 phase Typically have an isolating transformer Harmonic producing device Need to consider upstream transformer sizing: Large enough to address the harmonics Prevent oversize due to the low utilization rate of chargers, especially if using shift-change charging
Ventilation and Cooling Iterative approach between mine and ventilation engineers Criteria to base the Ventilation design for BEVs Temperature, dust, air velocity, clear blast gases Mine life, production profile, OWHS Some differences: No need to dilute diesel particulate Heat sources
Air Volume
Regulations Air quality is typically regulated by various agencies: Federal and local regulations Internal mining company standards The mine air volumes will be influenced by the regulatory requirements
Equipment Fleet Need to know: Quantity of each type of equipment Power rating for each type of equipment Anticipated utilization Need to work with manufacturers to determine the heat generation
Heat Load Need to consider all heat sources: All electrical equipment, including: Mine power centres, transformers, motors, VFD, chargers Mobile equipment Including batteries Auto compression Wall rock Any other sources
Heat Load Chargers Typical heat losses from charging equipment are 5-10%, but should be obtained from vendors Depending on placement of chargers, hot spots might be created in the mine 1x50kW charger, rated 5% losses, operating will generate 2.5kW of heat, which can easily be dealt with 4x400kW chargers, rated 10% losses, will generate 160kW of heat, which may be challenging to dissipate
Dust Control Reduced air volumes may not be sufficient to remove dust contaminants, depending on velocities Needs to be reviewed and may limit air volume reductions Drift sizes, air volume and localized air recirculation may need to be reconsidered
Dust Control
Blast Gas Clearing Time required depends on the air speed With a reduced airflow requirement, the time required may become longer than desired Important to review the clearing times during the design stage Considerations for capacity to increase airflow duing blast clearing VFD, louvers, automated ventilation control system
Air Monitoring Determine the real-time monitoring requirements Place instruments accordingly Consider maintenance and access to the equipment Typical sensors include: Carbon monoxide, sulfur dioxide, nitrogen oxides, dry-bulb temperature, humidity, air volume Dust is not commonly measured in real-time
Controlled Recirculation Typically limited due to the safety and health implications in diesel mines BEV presents an opportunity to use controlled full or partial recirculation If recirculation is part of the design, sufficient fixed monitoring is required to ensure regulatory compliance of air quality
Ventilation Design Process
Safety High level risk assessment is recommended to understand the total mine design risk with BEV More detailed assessments for critical risks identified Include items such as: Safety training Noise Power and voltage Air quality Heat Fire Geotechnical
Mine Design Conclusion Designing a BEV mine offer multiple opportunities Need to understand the topics to be explored and reviewed prior to implementation Both greenfield and brownfield mines BEV mine designers need to ask themselves new questions during the design process of a battery mine
Questions? Thank you / Merci Alain Richard Cheryl Allen alain_richard@bestech.com cheryl.allen@vale.com 705-675-7720 ext. 283 705-682-6857