Moving on to the business segment details. Slide 4 highlights results for In Process Separation segment, which delivered sales of $90 million on the fourth quarter, a 10% increase versus the fourth quarter 2010. Selling volumes increased by 3% as a result of continued strong production rates in our primary copper and aluminum-based metal markets. Additionally, the Commercial and Technology teams continue to do a great job commercializing new technologies which have led to both volume growth and improved product mix.
We have also been successful in our penetration of new geographies and in the quarter, secured new business in Latin America and Russia. Selling prices in the quarter were increased by 7% and more than covered cost escalation.
The segment delivered $20.4 million of operating earnings in the quarter, a remarkable 53% increase versus operating earnings of $13.3 million in the prior-year quarter and a record earnings quarter for this segment.
Slide 5 shows a summary of results in Engineered Materials segment, with sales up $239 million, a 16% increase versus the prior-year quarter. Selling volumes were up 11%, driven primarily by increased sales to the large commercial transport sector. New programs driving the growth include the Boeing 787, 747-8 and Airbus 380. The ramp-up in build rates for our legacy aerospace programs such as the Boeing 777, 737 and the Airbus 320 further supported the volume growth. In addition, civil and military rotorcraft programs are maintaining steady growth due to the general recovery in these markets.Selling prices increased sales by 3% as we continue to make progress offsetting the higher cost of raw materials that began to impact this segment in 2011. Operating earnings of $41.6 million were up significantly over the fourth quarter 2010 as a result of the higher volumes and increased selling prices with some of the pricing being retroactive to previous quarters. Read the rest of this transcript for free on seekingalpha.com