Tarshan Ring Excavations (TRE) was a mining company that operated on and around the planet Tarshan. Some time prior to 27 BBY, TRE approached the cloners of Kamino to produce cloned Humans as miners. The clones the Kaminoans produced were deliberately genetically-engineered to be sterile, though it was found that the clone prototypes displayed much higher rates of mental instability, poor group cohesion, and an inability to adapt and think creatively.

The Kaminoans attempted to redress the problem with synthetic hormones, rewiring cortical pleasure centers and dietary additives, but all cases improvement was minimal. The TRE experiment led Hali Ke, senior research geneticist of Kamino, to recommend that leaving Human clones with the ability to reproduce was the only way to guarantee an effective product. The lessons of the TRE experiment were applied in the Kaminoans' project to create the clone troopers of the Grand Army of the Republic.