Zinke told the Associated Press that "boundary adjustments" could be made to some of the monuments, while activities like hunting, fishing, or grazing could be opened up on others. But Zinke declined to comment on whether or not extractive industries such as oil and gas, logging, and mining companies would gain access to any of the monuments.
In April, President Donald Trump signed an executive order allowing for monuments designated by past presidents over the last two decades to be reviewed and rescinded. Trump called President Barack Obama's use of the Antiquities Act to create monuments an "egregious abuse of federal power" that stymied economic growth. No president has ever rescinded a national monument designation before, but some have adjusted the size of monuments in the past.
There's been no word from the White House yet on whether or not Trump will accept Zinke's recommendations.