We reached there at 3pm and was informed that there was an English guided tour just started. The admission was B$40 each but those taking photograph and video have to pay extra.
The door was locked everywhere after we visited and a security guard followed. I guess the exhibits worth so much, in monetary and historic value that only guided tour is allowed.
It contains ancient coins, wooden minting machines that was kept in the best condition around South America, precious stones and coin making equipments, showing the dark history of how indigenous and the black slaves had work here all day, dying of mercury poison.
The English guide explained in fine details, but didn't have much information about how many people worked here or how many hours they worked. The casa was probably locked up when it's was in production, without much written record apart from the standard of the silver coins, which was most important at the time.
The next day, before we left, we went to the plaza for a walk and found that there was a line of student parade in full fancy local costume. They were probably celebrating a Don Bosco festival
Then we took a micro and left for the terminal.