> If you just mean that it's impractical to build the electrical grid out to a remote mining site
Yes, that was the general issue. We do a lot of mining in remote sites that don't have hydro power or any realistic way to get it there. You could use biofuels, but it's hard to imagine bootstrapping a technical society to the point that that becomes feasible without prior use of fossil fuels.
http://www.hitachiconstruction.com/about/media-press-release...
http://www.oemoffhighway.com/article/11224086/electrificatio...
If you just mean that it's impractical to build the electrical grid out to a remote mining site, that's true. In the present day remote mining sites typically use diesel fueled generators, now being supplemented with photovoltaic arrays in sunny regions. If you imagine a world with approximately-1940-level technology (so PV is not yet an option) and no fossil fuel, then you'd need to use something like biodiesel or ethanol instead of fossil-derived diesel.