X0101 EFFECT 33 LIVE 2009-04-29 15:00:00

S-3

0001166036 MARKWEST ENERGY PARTNERS L P 333-157883 0001315263 MarkWest Energy Finance CORP 333-157883-27 0001292406 MarkWest Energy Operating CO LLC 333-157883-26 0001292407 Basin Pipeline LLC 333-157883-25 0001292408 West Shore Processing CO LLC 333-157883-24 0001292409 MarkWest Energy Appalachia LLC 333-157883-23 0001435921 Mason Pipeline LTD Liability CO 333-157883-22 0001292411 MarkWest Michigan Pipeline CO LLC 333-157883-21 0001292413 MarkWest Oklahoma Gas CO LLC 333-157883-20 0001292419 MarkWest New Mexico LLC 333-157883-19 0001292415 MarkWest Pinnacle LLC 333-157883-18 0001292416 MarkWest PNG Utility LLC 333-157883-17 0001292417 MarkWest Texas PNG Utility LLC 333-157883-16 0001292418 MarkWest Blackhawk LLC 333-157883-15 0001292414 MarkWest Power Tex LLC 333-157883-14 0001315242 MarkWest Pipeline CO LLC 333-157883-13 0001315262 MarkWest Energy East Texas Gas CO LLC 333-157883-12 0001349175 MarkWest Javelina CO LLC 333-157883-11 0001349174 Markwest Javelina Pipeline CO LLC 333-157883-10 0001435926 Matrex, L.L.C. 333-157883-09 0001435924 MarkWest Liberty Gas Gathering, L.L.C. 333-157883-08 0001435923 MarkWest Gas Services, L.L.C. 333-157883-07 0001436012 MarkWest Pioneer, L.L.C. 333-157883-06 0001412304 MarkWest Energy GP, L.L.C. 333-157883-05 0001019756 MARKWEST HYDROCARBON INC 333-157883-04 0001435922 MarkWest Marketing, L.L.C. 333-157883-03 0001457473 MarkWest Gas Marketing, L.L.C. 333-157883-02 0001457474 MarkWest McAlester, L.L.C. 333-157883-01