NEW YORK -- Freeport-McMoRan (FCX) - Get Report bounced from long-term lows at the end of last week, and bullish option traders are moving in.

OptionMonster's Heat Seeker system detected heavy buying in the May 21 calls for 28 cents to 31 cents in the first minutes of Friday's session. Some 11,500 contracts had traded at the time of the initial alert on our InsideOptions Pro subscription service, and volume approached 15,000 by the end of the day. 

Long calls lock in the price where investors can purchase a stock, which lets them position for a rally with limited risk. Their cheap cost can also result in significant leverage on a percentage basis. 

Freeport shares rose as much as 9%, doubling the value of those May 21 calls to 57 cents by the afternoon. The stock eased back into the close but still ended the day up 6.66% to $18.41. 

The copper and gold company has been sitting near its lowest levels in almost six years after months of strength in the U.S. dollar hurt sentiment toward metals and commodities. But the entire group has been trying to bottom out more recently as investors adjust to the possibility of an interest-rate hike by the Federal Reserve. Option traders have turned quick profits in steel makers recently as well. 

Freeport also saw a bullish spread in the afternoon as an investor bought 15,000 May 23 calls for 21 cents and sold an equal number of May 25s for 6 cents. The transaction cost 15 cents and will earn more than 1,200% if the stock closes at $25 or higher on expiration. 

Overall option volume in the name was five times greater than average in the session, with calls accounting for a bullish 71% of the total.

-- Written by David Russell of OptionMonster

Russell has no positions in FCX.