The employee was standing on left side of #32 Miner. The miner was off. EE was taking the control box off when a piece of draw slate (1.5""x1'x1') fell out of the top and struck the back side of EE's right hand causing a 2.5"" cut. The following were not a factor: rules, regs, mining equipment, protective devices on equipment or clothing, skills, proficiency, training or attitude.