The Company reported second quarter 2012 revenues of $104.6 million, an increase of $30.5 million, or 41% from the $74.1 million reported for the same period in 2011. Overall sales volume increased to nearly 1.8 million tons, or over 8% above the prior year sales volume of 1.6 million tons.
The Oil and Gas Proppants segment was the primary driver of year-over-year revenue growth. Second quarter Oil and Gas revenues were $54.5 million – up 111 percent compared to second quarter of 2011. The Company sold 685,000 tons of sand into the Oil and Gas markets for hydraulic fracturing, which produced $33.3 million in contribution margin for the second quarter, compared to 535,000 tons and a contribution margin of $16.7 million in the second quarter of 2011.
Second quarter Industrial and Specialty Products segment revenues were $50.1 million, a year-over-year increase of approximately 4%. The ISP segment sold 1,098,000 tons and delivered $14.0 million in contribution margin, compared to 1,106,000 million tons and a contribution margin of $14.8 million in the second quarter of 2011.
The ISP business segment represents the heritage of U.S. Silica and provides the Company a balanced portfolio of markets and customers. The ISP segment has more than 1,400 customers, produces over 200 products to such diverse end-markets as glass containers, flat glass, paint, chemicals and electronics.SG&A expense was $9.7 million for the second quarter of 2012 compared to $6.0 million for the second quarter of 2011. The increase was driven by additional staffing to support our growth and the administrative requirements of a public company. Adjusted EBITDA for the second quarter of 2012 was $37.1 million, an increase of 40% compared to $26.4 million for the second quarter of 2011. Capital Update As of June 30, 2012, we had $102.6 million of cash and cash equivalents and $24.0 million available under our credit facilities. Our total outstanding debt was $260.6 million. Capital spending for the first half of 2012 was $39 million.