Pruitt's 26 June 2018 memo proposing to rein in the EPA, removing their unilateral preemptive power to "short circuit" established permitting processes thus blocking new mining ventures. The EPA did this to the Pebble project, but have now been backed off and Pebble is free to proceed through normal permitting channels. 

https://www.epa.gov/sites/production/files/2018-06/documents/memo_cwa_section_404c_regs_06-26-2018.pdf