Image Source: Teck Resources 

What: Teck Resources Limited's (TECK 2.03%) stock moved higher by more than 31% last month. Add that to earlier gains and the miner's year-to-date rally tops out at around 90% or so. After a long spell of bad news, there are some positives finally showing up on the horizon.

So what: Teck Resources' big products are metallurgical coal, copper, and zinc. These have been tough commodities markets for a while, and that's driven the miner's shares sharply lower since the start of 2011 -- to the tune of around 88%, including the recent rally. But the miner posted a small profit in the final stanza of 2015, providing proof that all of the cost cutting and streamlining that Teck had done to deal with the commodity downturn is actually working.

However, there's another small piece to this equation, a 20% interest in an oil sands venture that's still under construction. This is part of Teck's move to diversify its assets, but couldn't have come at a worse time since the price of oil started to plummet in mid 2014. Teck was on the hook for billions of dollars for the development and the ongoing commodity downturn was making it harder and harder to come up with the cash. And for a project that was looking less and less viable in the face of falling oil prices.

So the first big news on this side of the equation was an upturn in oil prices this year. That suggests that the oil sands investment might actually work out over the long term, after all. But another important development was the news that Teck should be able to cover the remaining costs it faces for the oil project. It started the year with $1.8 billion in cash and $3 billion available under a line of credit that doesn't come due until 2020. As of February, when the company released fourth quarter results, it had around $1.2 billion in spending left on the oil sands project.

Cue investors breathing a sigh of relief since it looks like Teck will be able to survive the commodity downturn and invest in the future. With commodity prices firming again so far this year, notably for copper and zinc, investors have clearly taken a more positive view of the company and its bet on oil.

Now what: The recent rally in Teck's stock should make shareholders happy. But the shares remain down and out if you look back to 2011. There are plenty of risks here, to be sure, but for more aggressive investors who think that there are solid silver linings finally showing up on Teck's clouds, there's probably still time to jump aboard. Just don't expect the ride to be smooth, since volatile commodity prices are going to be the biggest determinant of Teck's near-term success.