There are a couple of possible explanations.

1. KRY had dropped by a greater percentage than GRZ so it is just playing catchup.

2. The price of copper has dropped over the past week. the value of GRZ's projected annual production from Brisas at present prices is split about 2/3 gold and 1/3 copper. @ $880 gold the Brisas mine would have an annual gross in gold of just over $400 million plus $228 million in copper revenues with copper at $3.80. Total $628 million gross annually of which 36% would be copper. A 20 cent drop in the price of copper drops $12 million off the bottom line for GRZ but it has no effect on KRY.