EXHIBIT 4 SECTION 16 AGREEMENT January 2, 2004 The Limited Partners of FRC-WPP NRP Investment L.P. and the Members of FRC-WPP GP LLC This letter sets forth certain understandings between and among the undersigned (for itself and in its capacity as...Section 16 Agreement • January 2nd, 2004 • First Reserve Gp Ix Inc • Bituminous coal & lignite mining
