MARDIN, Turkey — A 1st Infantry Division-led logistics task force has pushed deep into eastern Turkey to establish a new forward operating base just 100 miles from the Iraqi border.On the outskirts of the ancient mountaintop city of Mardin, the new outpost is near a small civilian airport and sits just off the main road leading to Turkey’s frontier with Iraq.The compound once served as a grain refinery and warehouse complex, according to local residents.Rain-soaked soldiers worked into the pre-dawn hours Friday, unloading dozens of Humvees, trucks, fuel haulers and other hardware after a grueling 15-hour convoy from southern Turkey’s...