Over the three year period ended December 2011, our refining business unit has continued to process regionally sourced low sulphur crudes through the CDU at a rate sufficient to meet domestic PNG demand for middle distillate products (diesel & jet fuel) supplied from the refinery, with occasional exports of ships bunkers. The Naphtha and LSWR that is consequentially produced has been exported into the regional market via spot and term contracts, although small amounts of LSWR are sold domestically in PNG.
For operational reasons, the CRU has remained out of service since March 2010. Prior to this shutdown, it had operated generally on a batch processing basis to meet domestic PNG demand for gasoline. It is anticipated that the CRU will be re-commissioned and returned to service during 2012, upon the successful conclusion of major maintenance and catalyst regeneration.
If, for operational reasons, we are unable to satisfy demand from refinery production we import finished products. Due to the continued shutdown of the CRU, the majority of gasoline we have sold during the period has been imported. During the fourth quarter of 2010, we undertook major turnaround maintenance on the CDU. Other than imports resulting from this scheduled event, our imports of middle distillates have been minimal and have not significantly affected our crude throughput.
We continue to source our crude through a supply agreement with BP. Under this Agreement, we negotiate directly with crude producers and sellers for the purchase of crude. However, the purchases are completed under our arrangements with BP and the subsequent shipments employ BP’s shipping infrastructure. There has been a natural decline in production of some of our preferred crude feedstock over the past three years and diversification of our crude feedstocks has been an important part of our crude acquisition strategy. We have introduced four new feedstocks to the refinery over the past three years, including our first West African crude. During 2011, we also concluded certain term purchase agreements for some of our preferred crudes for the 2012 year.
Whilst regional hydro skimming margins have suffered, particularly in 2011, our Import Parity Price (“IPP”) for products sold domestically affords us some protection from the low industry margins. Conversely, the IPP serves to restrict increases to our margin when margins are otherwise subject to upwards pressure. The IPP price formula has remained unchanged throughout the three year period, however, the changes agreed in late 2007 and early 2008 still remain to be formalized in our Project Agreement.
In 2010, our sales of middle distillates increased by 7% over 2009, then again in 2011 by a further 8% over 2010 volumes. These increases are primarily due to increased demand driven by resources projects in PNG. These increases have occurred in an environment where there has been continued importation of refined products by certain industry participants which we believe is contrary to our agreement with the State.
During 2011, there were seven export cargoes of Naphtha averaging approximately 28,506 metric tons each for a total of approximately 200,000 tonnes or 1.8 million bbls. The production of Naphtha at the refinery is variable and depends on the composition of the crude feedstock used, the relative economics for gasoline and Naphtha, and our ability (hampered during 2011 by our inability to operate the CRU) to convert Naphtha to gasoline. Also during 2011, there were seven export cargoes of LSWR totaling approximately 720,571 bbls under a combination of both spot and term arrangements that will continue into 2012.
During November 2009, we made an export sale of diesel and gasoline to the Pacific Island of Nauru. We made 3 additional export sales of diesel and gasoline to Nauru in 2010 and no export sales of diesel or gasoline in 2011. During 2011, our total throughput per day (excluding shut down days) was 24,856 bblspd versus 24,682 bblspd in 2010 and 21,155 bblspd in 2009. The total number of barrels processed into product at our refinery for 2011 was 6.73 million compared with 6.71 million for 2010, and 5.72 million in 2009. During 2011, our refinery was shut down for a total of 82 days, versus 81 days in 2010 and 80 days in 2009.
During 2011, management received results of an independent assessment of the potential asset retirement obligations of the refinery at the time of decommissioning and a provision for $4,100,735 has been recognized for this. The provision as at December 31, 2011 was $4,562,269. This decommissioning provision represents the net present value of the estimated costs of future dismantlement, site restoration and abandonment of properties based upon current regulations and economic circumstances as at December 31, 2011.