The increase in depreciation and amortization expenses was primarily due to the Badlands acquisition, CBF Train 4, Phase I of the international export expansion project, other system expansions and other assets placed in service during the last twelve months.
General and administrative expenses increased, reflecting increased support for our expanding business operations.
Other operating expense in 2013 includes the Versado joint venture cost of repairs less amounts covered by insurance ($3.7 million) related to a fire at the Saunders plant. Other operating expense in 2012 reflects losses due to Hurricane Isaac, which include the write-off upon closure of the Yscloskey joint interest processing plant and costs associated with the clean-up and repairs necessitated at our other Coastal Straddle plants.
The increase in interest expense primarily reflects higher borrowing levels to fund our business expansion ($9.4 million), offset by lower effective interest rates ($1.9 million) and higher interest capitalized on major capital projects ($4.0 million).
The increase in equity earning relates to our investment in Gulf Coast Fractionators ("GCF"), which turned a profit in 2013 compared to a loss in 2012 due to a planned shutdown of operations associated with its capacity expansion during 2012.
In July 2013, we paid $76.8 million plus accrued interest, which included a premium of $4.1 million, per the terms of the note agreement to redeem the outstanding balance of the 11¼% Senior Notes due 2017 (the "11¼% Notes"). The redemption resulted in a $7.4 million loss on debt redemption in the third quarter 2013, including the write-off of $1.0 million of unamortized debt issue costs.
The increase in other income was attributable to the elimination of the contingent consideration associated with the Badlands acquisition. The elimination of the contingent liability reflects management's updated assessment, with only nine months remaining in the contingency period, that we will not meet the stipulated volumetric thresholds.