I visited Pulacayo as part of my Bolivian trip (Sucre-Potosi-Uyuni-La Paz) to tick off the WHS (and TWHS) in that area. Pulacayo isn't on many itineraries but it's just 20 kilometers from Uyuni. Most tours go to the train graveyard of Uyuni but I think Pulacayo is much better.

The entrance fee is small and I do recommend taking a guide there (just a small fee) or if you're with a driver like me who speaks spanish and is local take him. I was able to get into the Aniceto Arce house as there was a historian doing research / cataloguing all the papers. Bedrooms, livingroom etc etc are all in good order with furniture still. Also it was interesting to see (in my case from 1944) a book with the results of the mine.

There was a lot of reconstruction going on at the site. They are preserving it well and i think it deserves to become a full WHS soon. Yes there are other sites maybe in other countries, but as this is important for Bolivia I think they deserve this nomination.

I recommend everyone to go; plan half a day either from Uyuni or if you drive from Potosi to Uyuni (which was what I did).