it also could be the anticipation of this

Nov. 20 Comex December gold options expire
Nov. 20 Comex December silver options expire

Nov. 24 Comex December miNY gold futures last trading day
Nov. 24 Comex December miNY silver futures last trading day

Nov. 28 Comex December gold futures first notice day
**1st day to take delivery**
Nov. 28 Comex December silver futures first notice day
**1st day to take delivery**

Dec. 29 Comex December gold futures last trading day
**Last day to take delivery**
Dec. 29 Comex December silver futures last trading day
**Last day to take delivery**

If December Gold or December Silver will fail to deliver it should happen between Nov 28 and Dec 29

Like john embry and others have said if everyone tries to take delivery we may see a default like the nickel market on the london exchange in 2006.