Whenever a company's management team speaks during a conference call, they tend to paint the company's future prospects in a bright light. This past quarter, U.S. Silica Holdings' (NYSE: SLCA) management went much further than that. Its CEO made an audacious promise to investors that, if it were to come true, would mean that this frack sand supplier's stock is embarrassingly cheap. Let's take a look at what U.S.