The Georgia Sierra Club is putting pressure on the Chemours Co. to publicly disavow any future involvement with a proposal to mine titanium next to the Okefenokee National Wildlife Refuge in South Georgia. A different company, the Alabama-based Twin Pines Minerals LLC, has proposed the mining operation and is awaiting a permitting decision from the Georgia Department of Natural Resources. But the Georgia Sierra Club fears that the larger and better established Chemours Co. could buy the Twin Pines project or the titanium it produces. "The ultimate aim is to save the Okefenokee National W...