Hecla Mining Co made an all-cash hostile bid to buy U.S. Silver Corp for C$110.7 million, a month after the Canadian company agreed to be bought by RX Gold & Silver Inc.

The offer price of C$1.80 per share represents a 22 percent premium on U.S. Silver's shares closing price on Wednesday.

"Hecla believes the intended offer will constitute a superior proposal...and represents a premium of 28 percent to the imputed offer price of C$1.41 under the RX Proposal," the company said in a statement late on Wednesday.