how do I get rid of hmining.mobi?

Try disconnecting your computer from the internet and quit your web browser. Reopen your browse, clear all web site data and cookies, then reconnect the computer to the internet.

If that doesn't help, contact > https://www.malwarebytes.com/support/ and see what they recommend.

Note that not all browser hijacks are actually due to adware or malware. They can be network-related, or they could simply be changes to your browser settings, or something else along those lines. So, if Malwarebytes Anti-Malware for Mac doesn't solve the problem, be sure to click the Next Steps button (directly below the Scan button).

I would use Malwarebytes, the Mac version was originally developed by a concerned long time ASC member.