On Wednesday, May 17, 2017 at 10:54:45 PM UTC+1, Andy Burns wrote:
Dave C wrote:

I would like to resurface that counter, and I am looking for
recommendations.

You might need to be careful with a scraper, the grain direction can
swap with each stave of the butcher block, so what works nicely in one
area can be a bit rough in neighbouring areas.

I've just sanded and varnished some oak butcher-block, but as a desk not
in a kitchen, used polyvine wax finish satin varnish, pleased with the
result, when it says apply sparingly it really means it, I then
literally gave it a single wipe with 0000 wire wool before a second
coat, even more sparingly.

dries in an hour or two, you are supposed to keep water splashes off it
for a few days after drying, which might be tricky in a kitchen.

I think it unlikley it is genuine butcher block. The 'butcher block' work tops I have seen are more what I would call strip laminations. (i.e.) the grain runs parallel with the surface instead of showing end grain surfaces. It amazes me how people can get away with incorrect terminology like this. Bit like all those supposed mahoganies out there.
Totally unsuited for the application hence the o.p's problem with stains and re-finishing. Formica is a much superior surface for a kitchen worktop. Thats genuine formica not melamine surfaced board, i.m.h.o. Wifey got marble last time. More overkill. As for cast concrete work tops, in the name of god, utter madness.

As for re-finishing. I would take a good random orbit sander to it. Start with 120g if that doesn't do it drop to 80g then work your way up through the grits. Personally I would stop at 320g but keep going if you want a super high finish.

Finish with a two pack epoxy if you have spray equipment and the patience to mask off the surrounding area,

Failing tha a good polyurethane woul be the next choice avoid water based finished like the plague.