BHP BillitonBHP Billiton ( BHP) is having a good run since June -- shares of the $121 billion mining stock have rallied more than 22% since the start of the summer. But a rally isn't worth talking about; more important than BHP's rally alone, the rally has been orderly. That's what makes this a tradable name right now. Since June, BHP's rally has been setting up within a channel, bouncing between trendline support to the downside and trendline resistance to the upside. Those two lines give traders a high probability range for this stock's trading, and a handful of optimal entry points for buyers. The best place to be a buyer is after a bounce off of trendline support -- that's because it's the place where risk (the distance from BHP's current price to the spot where the pattern breaks) is minimized. With shares near resistance now, that means that buyers will have to be a little more patient with this name right now. But that patience should pay off... Waiting for the bounce to happen is pretty critical. That's because trendlines do eventually break, and when they do, you don't want to be left holding the bag. Waiting for BHP to show that it can still catch a bid at support dramatically increases the chances of a successful trade here.