THE CERTIFICATED AIRLINE TRANSPORT PILOT WAS LANDING AT A PRIVATE AIRSTRIP WITH 4 PASSENGERS ON A FLIGHT CONDUCTED UNDER 14 CFR PART 135. THE AIRSTRIP IS 3,000 FEET LONG AND 20 FEET WIDE. DURING THE LANDING ROLL THE LEFT MAIN GEAR STRUCK A DIRT BERM THAT WAS DEPOSITED ON THE RUNWAY BY RECENT DUST STORMS. THE AIRPLANE DEPARTED THE HARD SURFACE OF THE RUNWAY. THE LEFT GEAR STRUCK SOFT TERRAIN AND WAS SHEARED OFF FROM THE AIRFRAME. THE AIRPLANE WAS SUBSTANTIALLY DAMAGED. NO INJURIES TO THE PILOT OR PASSENGERS. THE LANDING GEAR WIDTH OF THE AIRPLANE IS 18 FEET.