miners have no control over the fees! it is the network that determines how much the highest fee for highest priority is. right now there are 53K unconfirmed transactions in the mempool which means the fees will keep on rising as people pay higher and higher to get a high priority so that their transaction be mined in the next block found.
of course they wouldn't pay higher than certain amounts like 10000 satoshi/bye for example! so there will be a cap to it too.
you can also say it is the users who control the fee. but it certainly has nothing to do with miners.