Shares of silver mining companies Thursday extended the previous day's gains, many rising by more than the increasing value of silver itself.

The gray metal, which gained 1.71 percent on Wednesday, was up 3.06 percent to $31.28 in midday trading on the Comex, with spot silver climbing to $31.15.

Many silver mining companies rose more than the metal they produce: Endeavour Silver Corp. jumped 6.36 percent, Great Panther Silver Ltd. added 6.09 percent, Fortuna Silver Mines Inc. was up 5.41 percent and First Majestic Silver Corp. increased 4.09 percent.

Shares of silver exchange-traded funds also climbed: iShares Silver Trust rose 1.96 percent, Sprott Physical Silver Trust climbed 5.69 percent and Global X Silver Miners was up 3.53 percent.