I'm not sure what might be considered "normal" buyiing activity on the Perth Mint Bullion site but I placed two online orders this week 1st Feb 2:58pm AWST - Order Number 324076x (last digit not displayed) 3rd Feb 8:34am AWST - Order Number 324448x (last digit not displayed)
So I guess this means that in the space of roughly 8.5 trading hours, the mint has received more than 3700 orders which is an order rate of a little over 460 orders per hour.
Obviously not all silver and quantities are unknown, but to me it seems to be quite a high amount of activity. It will be interesting to see whether this continues or possibly slows down. I guess that means I'll need to place another order later this month to assess !!
