Thompson Creek Metals Company (NYSE: TC) is an interesting, soon-to-be diversified play on molybdenum, although it does come with some risks.

The miner currently operates two molybdenum mines: its namesake Thompson Creek in Idaho and the Endako mine in British Columbia, Canada. Between the two, the company produces about 28 million pounds of the grey metal each year.

In addition to its mines, Thompson Creek also owns a metal roasting facility that is used to refine the raw molybdenum into a pure oxide. That makes the company among only three suppliers of pure molybdenum products in North and South America.

Thompson Creek was a high-flyer prior to the recession, fetching better than $25 per share back in 2007. Post-recession, the company has been plagued by low molybdenum prices. The company has also run into trouble, thanks to its efforts to diversify its operations.

The company has been working to develop a new copper and gold mine at Mt. Milligan in British Columbia. With proven and probable reserves of 2.1 billion pounds of copper and 6 million ounces of gold, the mine would essentially be a piggy bank for Thompson Creek over the next 22 years, with 40 percent of the mine’s gold already sold to Royal Gold (NSDQ: RGLD).

But the Mt. Milligan project has been dealt numerous overruns over the past few years, as costs have shot up from an estimated $815 million at the start of the project to the ultimate total of about $1.5 billion.

The mine is finally on track to open sometime in the third quarter, with commercial production beginning in the fourth. All necessary contracts have been placed and financing secured.

Thompson Creek has also run into problems at its Endako mine over the past year. A harsh winter slowed down operations and recovery rates have fallen, all of which served to drive up cash costs. Given the weak molybdenum prices of late, those problems helped to push Thompson Creek to a loss in 2012.

But there are positives.

Not only does Thompson Creek still have more than 515 million pounds of molybdenum reserves, it will soon be adding copper and gold to its mix as well. And its copper and gold production costs will be surprisingly low at an estimated $280 while generating $575 in revenue, assuming copper is priced at $1.60 per pound and gold at $690 per ounce.

While molybdenum may be what we’re most interested in, copper and gold will provide a nice boost for the shares once production begins. Mt. Milligan should be in the black almost from day one, thanks to the low cash costs.

Thompson Creek is a more speculative play at this point, but the global economy won’t remain this weak forever and demand for stainless steel and other products that rely on molybdenum are bound to recover, particularly as China has severely curtails its exports. At the same time, there is a clear short-term upside catalyst as Mt. Milligan begins operation.

Thompson Creek’s shares are trading at just 0.3 times book value, a price that doesn’t account for the value of the company’s underlying assets, making the stock’s valuation very attractive.

Although Thompson Creek Metals Company still faces some challenges, it’s a buy under 4.