i'm going underground

I've arrived in Potosi (officially the highest city in the world, fact fans) really just trying to kill a few days before meeting Ursula near the argentinian border. I was suprised the town, although cold and breathless was pretty and my hostel was full of friendly people (luckily i got the very last bed and great views over the city).
Potosi is famous for its large silver mine and it is even possible to visit the mines and so in a very gringo-like manner i booked a tour and off i went, well after being dressed in suitably ridiculous clothing that is. The first stop on our tour was the miners market where we were able to buy various gifts for the miners, soft drinks, coca leaves, chocolate and most excitingly for us- dynamite. Then on to the processing rooms where the minerals are recovered. This basically was huge rooms filled with horrid smelling chemicals none of which were covered or kept away from human hands- our guide found it amusing to smear silver dust on our faces, we did too until he told us the other ingredient in the mixture was lead!
And now to the actual mine, upon reaching the entrance i did feel slight trepidation at descending deep into the mountain. The disclaimer i'd signed stating that in the event of a mine cave'in and my death the mine would not be responsible swam vividly before my eyes. I took a deep breath of the clean mountain air pulled up my face mask and followed the others of my group inside. It wasn't long before we reached a shrine to the devil (affectionately called uncle george) who the miners believe to be the god of the underground (and therefore their god whilst at work), we left some coca leaves and asked for safe passage through the mine.
The mine was hot and dark, the air very dusty and the miners we saw seemed to work tirelessly in these horrible conditions. As we descended into deeper levels the passages we crawled through became narrower but the loads the miners had to transport got bigger. Although it wasn't frightening it certainly wasn't pleasant and thinking that the miners do this all their lives was pretty awful, we finally reached a rock face that miners were working on; three of them chiseled the face whilst two of them sat in a preceeding chamber chewing coca leaves (they eat nothing in the mines for the entire 10 or more hour shifts). I had a go at chiseling a hole for the dynamite and was utterly terrible- we then watched the foreman show us how to do it and he asked us to help by singing a song. Our version of 'Help' by the Beatles (terribly sung) did go down very well, they shock our hands and thanked us for the coca leaves and soft drinks we left.
Everytime we passed a group and gave them either coca leaves or a soft drink they removed there filthy gloves to shake our hands, smiled and proudly explained their particular role in the mine, they then got straight back to work- lifting, pushing, hammering. And i was left feeling slightly uncomfortable at the fact that their incredibly hard work was fast becoming a tourist attraction. Despite the gifts and no matter how sensitive/responsible a tour you take didn't they feel even just a bit of hostility towards us coming down and taking photos?