Speaking to the Mountain

I've received several emails over the years asking me about Mark 11:23 in which Jesus appears to say that we can speak to a mountain and command it to be cast into the sea and as long as we do not doubt in our hearts, that it will do just that. Is this biblical evidence for the Word-Faith/N.A.R. doctrine known as Positive Confession? Do we as believers have the authority to command inanimate objects to do our bidding?