Alcoa Corp. (AA) released its second-quarter results after Thursday's closing bell, and the numbers were a bit of a mixed bag. The aluminum giant missed analysts' earnings estimates, even as revenue came in ahead of expectations.

Alcoa reported quarterly earnings of $2.12 per share, which fell short of the Street estimate of $2.25 by 5.78%, according to market data. On the top line, revenue hit $3.97 billion, beating the analyst consensus of $3.94 billion.

Here's a closer look at the operational details:

• Production: Alumina production dipped 6% sequentially to 2.2 million metric tons. In the Aluminum segment, production rose 5% to 636,000 metric tons.
• Shipments: Third-party alumina shipments were flat at 1.6 million metric tons. Aluminum shipments jumped 18% sequentially.
• Revenue: Total third-party revenue increased 24% sequentially to $4 billion. Alumina segment revenue slipped 3%, while Aluminum segment revenue surged 31%.

CEO William F. Oplinger highlighted the company's strategic progress: "During the second quarter, in addition to delivering strong financial results that captured favorable aluminum prices, our team executed on strategic initiatives, most notably the announced agreement with South32."

Investors weren't thrilled with the earnings miss. Alcoa shares were down 2.88% to $45.45 in Thursday's extended trading session.