Took the following information from the Nevada Gaming news. Perhaps it will cover Silver Strikes also.

The Nevada Gaming Control board has imposed a change which will effect all future Commerative,or limited edition chips. Every chip now issued must have a minimum mintage of 500. Although the control board did not return our calls for specific reasons,it is widely believed several collectors/investors have worked with certain Casinos to produce a very low Mintage issues. In doing so the investor (s) reportedly controlled the distribution & perceived value of certain chips.