Check this page: http://www.nasdaq.com/quotes/institutional-portfolio/sprott-inc-848276/decreased?sortname=changepct&sorttype=0
Sprott has decreased pretty much all of its positions in silver miners (SSRI and Silvercrest are the only one exceptions).
Seems to me that they needed cash either because they got redumption calls or becaause they need this cash to concentrate their efforts on the real war front : physical silver.