By midafternoon, shares had gained 19.2% to 58.4 cents.
Trading volume of 17.8 million was more than double its three-month daily average.
"We are pleased with the overall increase in contained palladium ounces in our reserves and resources and the improved economics of our updated life of mine plan for LDI," said president and CEO Phil du Toit in a statement.
"Our operations are performing well year to date and the fundamentals for the palladium market remain favorable. As we continue through 2014 we will focus on continued operational improvements, lowering unit costs and further diamond drilling to potentially convert our large mineral resource to reserves," he continued.
The Toronto-based miner said total reserves and resources increased 24% above the January 2013 technical report to 5.2 million ounces of contained Pd. Total reserves increased by 140,000 of contained Pd to 1.3 million ounces. This is an increase of 12% compared to the previous technical report.
The company also said it plans to continue investing in surface and underground exploration and conversion drilling. Its 2014 campaign is scheduled to begin at the end of March.
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TheStreet Ratings team rates NORTH AMERICAN PALLADIUM as a Sell with a ratings score of D. The team has this to say about their recommendation: