Thank you for taking the time to reply. I was just concerned because we did not use masks, had no ventilation and it has 60% plaster of Paris. Have you had such exposures?It is very unlikely that you'll develop silicosis within 3 days, if that was the case there would be no one here to answer your question.
I've been a plasterer for 38 years and been exposed to all sorts of dust and I don't have any lung conditions. So 3 days of exposure is unlikely to be harmful.
So you're clever enough to type a question, but not clever enough to wear a dust mask? I suppose this proves the theory of apes typing out the complete works of Shakespeare given time.