@TAKEOFFGood to hear that companies (if not governments) are aware of the necessity to reduce carbon emissions for commercial reasons and hopefully environmental reasons too.
In my opinion, it is vital that all miners and manufacturers implement carbon reduction measures to ensure they will not be penalised by tariffs imposed by importing countries, on products that are not produced with regard to carbon emissions.
For the standard electrical vehicle (car), I believe that Lithium batteries will be the preferred option, as they are generally not required to operate 24 hours a day, and the charge time can be accommodated by most users, and can potentially be charged from a user's home. The refuelling from home option for a pure EV is in contrast to hydrogen fuel cell powered electric cars which would need to locate a hydrogen 'service station' to refuel.
For 'heavy haul' mine equipment however, I believe that electric trucks powered by hydrogen fuel cells, where the hydrogen is produced by renewable energy, might be a option. Because the hydrogen fuel cell electric haul truck is operating in a relatively small geographical area, the refuelling point is always nearby. The time required to refuel a hydrogen fuel cell is short in comparison to battery charging. To charge a battery at the rate suggested in the article posted by @TakeOff, would require the batteries be able to receive such a high rate of charge as well as the charge point being capable of delivering the required energy. Both of these issues will be a big challenge to resolve.
The conversion of 'H2O to hydrogen and hydrogen back to electricity' is much less efficient (about 60% loss) than charging a Lithium battery (about 20% loss), but if that conversion process is powered by renewable energy, despite the inefficiency, the convenience of short refuel time might make this a feasible option. The storage of hydrogen as ammonia increases it's density (more energy per volume) and allows it to be available for safer, transport and rapid refuelling.
Also, remember that even vehicles with hydrogen fuel cells still have a small lithium battery to provide the immediate power required by the electric motor. I don't think this is a battle of hydrogen versus lithium. They both have a part to play in the appropriate situation and in combination.
These sites ( and many others) have information on the conversion of electricity to hydrogen to ammonia etc...https://www.sciencemag.org/news/2018/07/ammonia-renewable-fuel-made-sun-air-and-water-could-power-globe-without-carbonhttps://www.sciencedaily.com/releases/2020/11/201118141718.htmhttps://www.forbes.com/sites/peterdetwiler/2020/12/16/maybe-the-hydrogen-economy-will-become-the-ammonia-economy/?sh=6e3cd97e4936https://www.forbes.com/sites/jamesmorris/2020/07/04/why-hydrogen-will-never-be-the-future-of-electric-cars/?sh=7e80a38512fa
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