X0202 4 2006-08-30 0 0001166036 MARKWEST ENERGY PARTNERS L P MWE 0001270065 SEMPLE FRANK M C/O MARKWEST ENGERGY PARTNERS, L.P. 1515 ARAPAHOE ST, TOWER 2, STE 700 DENVER CO 80202 1 1 0 0 President, CEO Common Units 2006-08-30 4 M 0 1875 48.40 A 20543 D Phantom Units 2006-08-30 4 M 0 1875 0 D Common Units 1875 0 D 1 for 1 Under the phantom unit grant agreement, the settlement of the phantom units occurs automatically as the phantom units vest, which results in a deemed automatic expiration of the vested portion of the phantom units upon settlement. The phantom units vest generally over of period four years, with 25% vesting at the end of the second and third years after the date of grant, and 50% vesting at the end of the fourth year after the date of grant. The vesting may be accelerated in certain instances if the issuer achieves certain unitholder distribution targets. /s/ Sean M. McKendry POA for Frank M. Semple 2006-08-31