NRI steel tycoon Lakshmi N Mittal may partner Hindustan Petroleum Corporation (HPCL) in the under-construction $3 billion refinery at Bhatinda in Punjab."Mittal Investments and HPCL are close to signing a joint venture agreement for building the 9 million tonne a year Bhatinda refinery," an industry source said.As per the broad understanding reached between the two firms during preliminary talks, HPCL and Mittal Investments may hold 49% stake each in the Guru Gobind Singh Refinery, the company implementing the project. The remaining 2% would be offered to financial institutions.In the likelihood of state-run exploration firm Oil India (OIL) joining the project, the shareholding may be 26:26:26. The balance would be offered in an initial public offering (IPO) closer to commissioning of the refinery in 2010-11.Mittal is the latest in a series of joint venture partners HPCL has been in talks for the Bhatinda refinery. BP of UK walked out of the project in March this year. Earlier, Saudi Aramco of Saudi Arabia had exited the project in 1998.Mittal Investments is wholly-owned by the Mittal family and is registered in Luxembourg. It hold 38% in Mittal Steel Company, the Netherlands-based flagship company of the LN Mittal Group.Officials of both Mittal Investments and HPCL could not be immediately reached for comments.The source said the Mittals may extend the partnership with HPCL to also include participation in the expansion of 7.5 million tonne a year Vizag refinery and joint pursuit of oil assets abroad.