This one in particular is interesting, I have noticed it before, I believe the exemptions is for manufacturing business and was not sure if mining could fit in that category. As far as the "larger-scale" requirement, I do not remember seeing anywhere a size / scale requirement, any more info on that or what exactly constitutes large enough to get that exemption?
It looks like the customer needs to go through a long process:
https://electricityplans.com/electricity-sales-tax-exemption/Probably only worth the time/expense for farms larger larger 1 MW. The extra 8% probably comes out to 2-4% less profit.