TRUCK DRIVER TOLD ROCKBREAKER OPERATOR THAT HE HAD AN OIL LEAK. THE OPERATOR PULLED OVER AND SWUNG MACHINE AROUND. IT WASN'T FULLY LEVEL. HE CALLED FOR A MECHANIC. MECHANIC & OPERATOR ADDED OI L TOT HE MACHINE. OPERATOR WAS ASKED TO START MACHINE. GOING DOWN TO START MACHINE, HE TRIPPED OVER THE OIL CAN LEFT ON THE CATWALK, FALLING ONTO THE TRACKS HURTING HIS RIGHT SIDE BACK AREA.