I'm not familiar with him in the games. If a pokemon used fly or dig would Machamp still be able to hit them?
Yes. The attacks can still be blocked with Protect or a Substitute. It doesn't bypass immunities so a Ghost Pokemon would not be hit by a Normal or Fighting type attack.
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Pokemon VGC2011 US Nationals - 54th place
Pokemon VGC2012 NW Regional - 16th place